The utilization of dietary local feed resources for moo lath pig in laos

ABSTRACT The research was objected to investigate the effect of ensiled taro foliage combined with banana pseudo stem as basal diets, using by-product of rice distillers or brewers’ grai

HUE UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY

HUE UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY

DOCTOR OF PHILOSOPHY IN AGRICULTURE

SUPERVISORS: 1 ASSOC.PROF.DR NGUYEN QUANG LINH

2 ASSOC.PROF DR DU THANH HANG

HUE, 2019

DECLARATION

I declared that this thesis is my original research works It is a scientific research which overall data presented in this thesis are contributed truly and righteously The research works was done under the guidance of Professors in Hue University and collaborative professional researchers All acceptation is evidently indicated to the best of immense knowledge that they have been published in Journal of Livestock Research for Rural Development (LRRD)

Hue, April 2019

Bounlerth SIVILAI

ACKNOWLEDGEMENT

This thesis describes research on the improving and utilization of forage- based diets for Moo Lath pigs in Laos, I wish to thank Mekong Basin Animal Research Network (Sida/MEKARN II) project and University of Agriculture and Forestry, Hue University for financial support of experiments and the course works in Vietnam

This thesis based on the efforts of many people In the first place, I would like to thank all those persons who contributed to obtaining the data and the texts of the various chapters Without their help this thesis would never been written Especially, I would like

to express my sincere thanks to Professor Nguyen Quang Linh, Professor Thomas Reg Preston, who always open the gates to scientific research I am also grateful for their supervision and guidance of my research I would like to express my heartfelt thanks to Professor Du Thanh Hang, who supervised the data analysis It would be nice to thank for all of lecturers and researchers in Hue with hospitality while my staying in Hue city I am grateful to Dr Lampheuy Kaensombath and professor R.A Leng for their contributions and helping

My sincere thanks also goes to Dr Kieu Borin, regional coordinator of the Sida/MEKARN II project for any support and make the PhD program possible and Dr Chive Phiny for the budgets for travelling and allowances Dr Vanthong Phengvichit and

Dr Daovy Kongmanila the country coordinators for providing the immense suggestion

on study condition and financial report as well as accountants in National Agriculture and Forestry Research Institute (NAFRI) for arrangement research funds conveniently Also thank my colleagues, friends and teachers in Department of Livestock and Fishery, Faculty of Agriculture (FAG), National University of Laos for their kindly supports My lovely students and their friends whom helped in field works with forage collecting, experiments and sample preparing analysis

Last but not least, I would like to thank my family for all their kind regards, encouragement and love Most of appreciation to my wife Linh Thamavong for her patience, effort working hard and taking care for our family during my studying Special thank to my mother for her support, loving and devotion to my three children during studying time Great thanks to my sister Boakeo Phaisilai and her husband, my younger sister Boasone Sivilai and my uncles’ family for their help in looking my mother,

ABSTRACT

The research was objected to investigate the effect of ensiled taro foliage combined with banana pseudo stem as basal diets, using by-product of rice distillers or brewers’ grains, and biochar as feed additive supplemented in the diet of native Moo Lath Lao pig Four experiments were conducted to comprising on the thesis

The first experiment (Chapter 2): Four pigs were used in the experiment with 30

kg  2.63 kg LW An experiment was arranged in a 4*4 Latin Square Design with diet levels of ensiled banana pseudo stem of 0, 5, 10 and 15% replacing ensiled taro foliage and soybean meal Apparent digestibility of DM and CP, daily N retention and biological value (BV), all declined linearly as ensiled banana-pseudo stem replaced ensiled taro foliage It is appeared that the BV of the protein in the ensiled taro foliage was superior to combination of ensiled banana pseudo stem and soybean meal

In the second experiment (Chapter 3): A small amount of either rice distillers’ product (RDB) and brewers’ grain (BG) were added in the ensiled forage-based diet Six female native Moo Lath pigs (29.3  2.3 kg LW), fed a basal diet of ensiled banana pseudo-stem, ensiled Taro foliage and broken rice were allocated to a 3*3 double Latin Square Design Three treatments were BG 4%, RDB 4% or no supplement (CTL) Both supplements improved feed intake, digestibility and N retention, with indications of greater responses in N retention and in the biological value of the protein for the rice distillers’ by-product It is suggested that the beneficial effect of both supplements may have been due to the presence of β-glucan, a component of the cell wall of both cereal grains and yeasts, that is shown to have immunological, health-benefiting effects in animal

by-In the third experiment (Chapter 4): The supplements would bring similar benefits during the stage of pregnancy and lactation in Moo Lath gilts Twelve native Moo Lath pig gilts (80.8 ± 3.9 kg LW) were used in the experiment Three dietary treatments in a completely randomized design with 4 replications were: CTL: No supplement; RDB 4%

or BG 4% in diet DM basis The pig gilts gained more body weight during gestation, and were heavier at the end of lactation, when their diet was supplemented with 4% BG or

4% RDB The litter sizes from dams supplemented with 4% RDB were heavier at birth,

and at weaning, and grew faster than litters from un-supplemented gilts Supplementation

of BG4% or RDB 4% appeared to have no effect on piglet mortality at birth or during lactation, nor on live weights of piglets at birth or weaning, and did not affect overall feed

DM intake However, DM feed conversion was improved by 60% when the Moo Lath gilts were supplemented with 4% RDB

In the fourth experiment (Chapter 5): The study was to evaluate the effect of biochar compare with rice distillers’ by-product fed a forage diet on growing pigs Twenty native Moo Lath pigs (15.8 ± 1.3 kg LW) were housed in individual concrete pens There were four dietary treatments arranged as a completely randomized design The treatments (% in diet DM) were: no additive (CTL), 4% rice distillers’ by-product (RDB), 1% biochar (BIO) and the combination of RDB and BIO (RDB+BIO) The

growth rate tended to be better (p=0.089) and feed conversion was improved (p=0.048) for both additives, fed separately or together, when compared with the control

diet There were no benefits from combining both additives compared with feeding each one separately

Keywords: Local forage, prebiotic, additive feed, indigenous pig, biological

value, growing, pregnancy-lactation, piglets

DEDICATION

To my family with my respectful gratitude: Parents, my wife (with daughter and son),

older and younger sisters ແດ່ຄອບຄົວທີ່ແສນເຄົາລົບຮັກຂອງຂ້ອຍ: ພໍ່ແມ່, ພັນລະຍາ

(ພ້ອມດ້ວຍລູກສາວ ແລະ ລູກຊາຍ),

ເອື້ອຍ ແລະ ນ້ອງສາວ

TABLE OF CONTENTS

DECLARATION I ACKNOWLEDGEMENT II ABSTRACT III DEDICATION V TABLE OF CONTENTS VI LIST OF TABLES IX LIST OF FIGURES XI LIST OF ABBRIVIATIONS AND SYMBOLS XIV

INTRODUCTION 1

1 BACKGROUND OF THE STUDY 1

2 AIMS AND OBJECTIVES OF THE STUDY 4

2.1 Aims of the thesis 4

2.2 Objectives of the thesis 4

3 HYPOTHESES OF THE RESEARCH 4

4 INNOVATION CONTRIBUTED OF THE DISSERTATION 5

REFERENCE 6

CHAPTER 1: LITERATURE REVIEW 10

1.1 PIG PRODUCTION IN SMALLHOLDER OF LAOS 10

1.1.1 The role of pig production 10

1.1.2 Pig population and consumption 10

1.2 CURRENTLY TYPICAL PIG FARMING IN LAOS 11

1.2.1 Smallholder pig farming 12

1.2.2 Semi-intensive pig production 15

1.2.3 Commercial scale pig production 16

1.3 Feeds and feeding practical management in smallholder pig farms 17

1.3.1 Feeds derived from agricultural by-products 17

1.3.2 Green plant materials as feeds for pigs 18

1.3.3 Feeds derived from leftover materials 18

1.4 CONSTRAINTS AND OPPORTUNITY IN SMALLHOLDER FARMS 18

1.4.1 Main problem in smallholder pig production 18

1.4.2 Opportunity improvement of pig productivity 19

1.5 ALTERNATIVE USE OF LOCAL FEED RESOURCES FOR PIGS 20

1.5.1 Taro foliage (Colocasia esculenta) 20

1.5.2 Banana pseudo stem (Musa spp) by-product 22

1.6 UTILIZATION OF FORAGE-BASED DIET FOR PIGS 23

1.6.1 Taro as protein sources for pigs 23

1.6.2 Effect of taro foliage on apparent digestibility and N retention in pigs 23

1.6.3 Effect of taro foliage on growth performance of pigs 24

1.6.4 Effect of taro foliage replacing by banana pseudo stem in pig diets 25

1.7 GRAIN FERMENTED BYPRODUCTS AS SUPPLEMENT FEED FOR PIGS 27 1.7.1 Rice distillers ( Khi-Lao) by-products 27

1.7.2 Brewery grain ( Khibeer )by-product 29

1.8 UTILIZATION OF GRAIN FERMENTATION BYPRODUCTS 32

1.8.1 Use of rice distillers’ by-product or brewers’ grains as protein sources 32

1.8.2 Effect of rice distillers’ by-product or brewers’ grains as supplement feeds 33

1.8.3 The use of biochar as a feed additive in animals 33

1.9 NUTRIENT REQUIREMENT OF PIGS 34

1.9.1 Dietary protein requirement 34

1.9.2 Dietary energy requirement 35

REFERENCES 36

CHAPTER 2: EFFECT OF REPLACING ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) WITH ENSILED BANANA PSEUDO STEM (MUSA SPP) AND SOYBEAN MEAL ON INTAKE, DIGESTIBILITY AND NITROGEN RETENTION IN MOO LATH PIGS 49

CHAPTER 3: A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT OR OF BREWERS’ GRAINS ON DIGESTIBILITY AND NITROGEN RETENTION IN NATIVE MOO LATH PIGS FED ENSILED BANANA PSEUDO-STEM (MUSA SPP) AND ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) 58

CHAPTER 4: EFFECT OF A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT, OR OF BREWERS' GRAINS ON GROWTH RATE AND FEED CONVERSION DURING PREGNANCY AND LACTATION OF NATIVE MOO LATH GILTS AND THEIR PROGENY 70

CHAPTER 5: EFFECT OF RICE DISTILLERS’ BYPRODUCT AND BIOCHAR AS ADDITIVES WITH A FORAGE-BASED DIET FOR GROWING AND FEED

CONVERSION OF NATIVE MOO LATH PIGS 83

GENERAL DISCUSSION AND CONCLUSION 95

1 GENERAL DISCUSSION 95

2 CONCLUSIONS 97

3 IMPLICATIONS FUTURE RESEARCH 98

3.1 Implications 98

3.2 Future research 98

REFERENCES 99

LIST OF PUBLISHED SCIENTIFIC PAPERS 102

LIST OF TABLES

CHAPTER 1: LITERATURE REVIEW 10

Table 1.1 Number of livestock products and meat consumption in 2017 11

Table 1.2 Classification of phenotype characteristics and reproductive performance of native pigs distributed in smallholder farm conditions in Lao PDR 13

Table 1.3 Composition of taro plant in different parts of studying (% DM basis) 21

Table 1.4 Composition (g/kg CP) of EAA in the leaves of taro compared to soybean meal 21

Table 1.5 Oxalate contents in taro (total, soluble and insoluble oxalate) 21

Table 1.6 Nutrients content of banana stalk in fresh matter 22

Table 1.7 Chemical composition of the ingredients, the fermented mixture and the residue 27

Table 1.8 Chemical composition and gross energy of rice distillers’ by-product (% in DM basis) 28

Table 1.9 Crude protein (% in DM) and amino acid composition (g/16 g N) of rice distillers’ by-products 28

Table 1.10 Amino acid components in rice distillers’ by-product and ideal protein (g/16 g N) 29

Table 1.11 nutritional table of fresh brewers’ grains 31

CHAPTER 2: EFFECT OF REPLACING ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) WITH ENSILED BANANA PSEUDO STEM (MUSA SPP) AND SOYBEAN MEAL ON INTAKE, DIGESTIBILITY AND NITROGEN RETENTION IN MOO LATH PIGS 49

Table 2.1 Chemical composition of the ingredients in the diets 52

Table 2.2 Experimental diets and chemical composition 52

Table 2.3 Mean values for feed intake and apparent digestibility of diets 53

Table 2.4 Effect of ensiled banana pseudo-stem and taro foliage on N balance and retention in Moo Lath pigs 55

CHAPTER 3: A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT OR OF BREWERS’ GRAINS ON DIGESTIBILITY AND NITROGEN RETENTION IN NATIVE MOO LATH PIGS FED ENSILED BANANA PSEUDO-STEM (MUSA SPP) AND ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) 58

Table 3.1 Proximate composition of diet ingredients 62

Table 3.3 Mean values for DM intake and % CP of the diet consumed by Moo Lath pigs without (CTL) or with supplements of BG or RDB 63Table 3.4 Mean values for apparent digestibility by Moo Lath pigs fed diets without (CTL) or with supplements of BG or RDB 64Table 3.5 Mean values for N balance by Moo Lath pigs fed diets with or without (CTL) supplements of BG or RDB 65CHAPTER 4: EFFECT OF A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT, OR OF BREWERS' GRAINS ON GROWTH RATE AND FEED CONVERSION DURING PREGNANCY AND LACTATION OF NATIVE MOO LATH GILTS AND THEIR PROGENY 70

Table 4.1 Composition of experimental diets (% DM basis) 71Table 4.2 Proximate analysis of diet ingredients 74Table 4.3 Mean values for live weight (kg) of Moo Lath gilts at conception, before and after parturition and weaning 74Table 4.4 Mean values for changes in weight of Moo Lath gilts supplemented during pregnancy with 4% of rice distillers’ by-product or 4% brewers’ grains 75Table 4.5 Mean values for weight of litters from Moo Lath gilts supplemented during pregnancy with 4% of rice distillers’ by-product or 4% brewers’ grains 76Table 4.6 Numbers of piglets born and surviving to weaning supplemented with 4% of rice distillers’ by-product or 4% brewers’ grains 77Table 4.7 Mean weights (g) of piglets at birth and 28 day weaning supplementation of the diet with brewers’ grains, rice distillers’ by-product 77Table 4.8 DM feed intake from conception to weaning of Moo Lath gilts supplemented with 4% brewers’ gains or 4% rice distillers’ by-product 78Table 4.9 Effect of supplementing with 4% brewers’ gains or 4% rice distillers’ by-product on DM feed conversion (kg/kg) 78CHAPTER 5: EFFECT OF RICE DISTILLERS’ BYPRODUCT AND BIOCHAR AS ADDITIVES WITH A FORAGE-BASED DIET FOR GROWING AND FEED CONVERSION OF NATIVE MOO LATH PIGS 83

Table 5.1 Proximate composition of diet ingredients 87Table 5.2 Composition of experimental diets 87Table 5.3 Mean values for change live weight, feed intake and conversion for Moo Lath pigs fed rice distillers’ by-product, biochar or both 88

LIST OF FIGURES

CHAPTER 1: LITERATURE REVIEW 10

Figure 1.1 Number of pigs in Laos from 2013-2017 11

Figure 1.2 Lao name - Moo Chid (Moo Markadon or Moo Boua) 14

Figure 1.3 Lao name - Moo Lath 14

Figure 1.4 Lao name - Moo Nonghad or Moo Hmong 14

Figure 1.5 Lao name - Moo Deng or Moo Berk 14

Figure 1.6 Traditional rice distillers’ by-product production in Laos 29

CHAPTER 2: EFFECT OF REPLACING ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) WITH ENSILED BANANA PSEUDO STEM (MUSA SPP) AND SOYBEAN MEAL ON INTAKE, DIGESTIBILITY AND NITROGEN RETENTION IN MOO LATH PIGS 49

Figure 2.1 Effect of increasing level of ensiled banana pseudo stem replacing taro foliage on apparent DM digestibility in Moo Lath pigs 54

Figure 2.2 Effect of ensiled banana pseudo stem 54

and taro foliage on CP digestibility in Moo 54

Lath 54

Figure 2.3 Effect of ensiled banana pseudo stem and taro foliage on CF digestibility in Moo Lath pigs 54

Figure 2.4 Effect of ensiled banana pseudo stem replacing ensiled taro foliage on N retention in Moo Lath pigs 55

Figure 2.5 Effect of ensiled banana pseudo-stem replacing taro foliage on N retained as % of N digested in Moo Lath pigs 55

CHAPTER 3: A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT OR OF BREWERS’ GRAINS ON DIGESTIBILITY AND NITROGEN RETENTION IN NATIVE MOO LATH PIGS FED ENSILED BANANA PSEUDO-STEM (MUSA SPP) AND ENSILED TARO FOLIAGE (COLOCASIA ESCULENTA) 58

Figure 3.1 Metabolism cage for faces and urine collection 60

Figure 3.2 Chopped banana pseudo-stem 61

Figure 3.3 Rice distillers' by-product 61

Figure 3.4 Brewers' grains 61

Figure 3.5 Effect of rice distillers’ by-product and brewers’ grain on DM intake

by Moo Lath pigs 64

Figure 3.6 Effect of rice distillers’ by-product and brewers’ grain on apparent

digestibility of DM by Moo Lath pigs 64

Figure 3.7 Effect of rice distillers’ by-product and brewers’ grains on apparent

digestibility of crude protein by Moo Lath pigs 64

Figure 3.8 Effect of rice distillers’ by-product and brewers’ grains on apparent

digestibility of crude fiber by Moo Lath pigs 64CHAPTER 4: EFFECT OF A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT, OR OF BREWERS' GRAINS ON GROWTH RATE AND FEED CONVERSION DURING PREGNANCY AND LACTATION OF NATIVE MOO LATH GILTS AND THEIR PROGENY 70

Figure 4.1 Rice distillers’ by-product 73 Figure 4.2 Gilts and piglets during lactation 73

Figure 4.3 Effect on live weights of Moo Lath gilts at conception, parturition and weaning of supplementation with 4 % RDB or 4% BG 75Figure 4.4 Mean values for changes in weight of Moo Lath gilts during pregnancy 75Figure 4.5 Loss of weight of Moo Lath gilts during lactation 75Figure 4.6 Effect of supplementation with 4% brewers’ gains or 4% rice distillers’ by-product on litter weight at birth 76Figure 4.7 Effect of supplementation with 4% brewers’ gains or 4% rice distillers’ by-product on litter weight at weaning 76

Figure 4.8 Effect of supplementing with 4% brewers’ gains or 4% rice distillers’

by-product on weight gain of their litters from birth to weaning 76Figure 4.9 Effect on litter weight of piglets weaned of supplementing with 4% brewers’ gains or 4% rice distillers’ by-product 78Figure 4.10 Effect on DM feed conversion of the piglets weaned supplementing with 4% brewers’ gains or 4% rice distillers’ by-product 78CHAPTER 5: EFFECT OF RICE DISTILLERS’ BYPRODUCT AND BIOCHAR AS ADDITIVES WITH A FORAGE-BASED DIET FOR GROWING AND FEED CONVERSION OF NATIVE MOO LATH PIGS 83

Figure 5.1 The biochar was the residue from rice husks used as fuel in a gasifier stove 85Figure 5.2 Effect of additives (DM basis) of rice distiller’s by-products (4%) and biochar (1%) on DM intake of Moo Lath pigs 88Figure 5.3 Effect of additives (DM basis) of rice distiller’s by-product (4%) and biochar (1%) on live weight gain of Moo Lath pigs 89Figure 5.4 Effect of additives (DM basis) of rice distiller’s by-product (4%) and biochar (1%) on DM feed conversion of Moo Lath pigs 89

LIST OF ABBRIVIATIONS AND SYMBOLS

AA Amino acid

ADF Acid detergent fiber

ADG Average daily gain

LPHC Lao Population and Housing Census

LSB Lao Statistic Bureau

MAF Ministry of Agriculture and Forestry

ME Metabolizable energy

N Nitrogen

NDF Neutral detergent fiber

NRC National Research Council

INTRODUCTION

1 BACKGROUND OF THE STUDY

Livestock production plays a significant role as source of food and of cash income for smallholder farmers in rural areas in Laos There were 3.7 million pigs in Laos (DLF, 2017) Most of the pig mainly production in Laos is produced under traditional conditions with approximately 75% in rural smallholder pig farms (Souriyasack, 2011) The typical smallholder pig farm relies on a scavenging system for forages and left-over food with little or no supplementation Supplementary energy-rich feeds are rice bran, broken rice, maize and cassava root, but usually the price makes them out of reach of poor farmers The only sources of protein that farmers can afford are green plant material and naturalvegetables These feed resources are not available in all seasons and are imbalanced nutritionally, with lack of protein being the major issue The classical sources of protein used in pig production such as fish meal and soybean meal are almost exclusively imported and out of reach of smallholder farmers The results are low productivity (Stür

et al., 2010) with growth rates often less than 100 g/day (Phengsavanh et al., 2010) This means a production cycle of 1.5 to 2 years to reach market weight of 60 to 70 kg(Phengsavanh and Stür, 2006) The reproductive performance of sows is marked by

depressed litter size, a high mortality of piglet and outbreaks of disease

The only options so far available to most smallholder farmers are to make better use of the locally available feed resources and/or to introduce protein-rich plants that are

easy to grow such as the perennial leguminous forage Stylosantheses guiensis

(Phengsavanh and Stür, 2006) For these reasons the two feed resources chosen for this

research were banana pseudo stem (Musa spp) as source of energy and the Taro plant (Colocasia esculenta) as the source of protein

Banana pseudo stems (BPS) from the banana tree are distributed in Laos, as bananas are widely grown for production of fruit for family consumption and sale The total harvest area of banana trees in Laos was estimated to be 28,600 ha, with yields of 42 tonnes of fruit/ha (MAF, 2017) The stem of the banana trees is referred to as a “pseudo stem” as it appears to be held erected by water, not by lignified fiber as in most trees After the fruit is harvested this pseudo-stem is either left to rot on the ground or is

occasionally harvested, chopped into small pieces and fed to pigs, ducks and chickens (Tien et al., 2013)

Banana pseudo stem has 8.5% lignin in DM, more than twice that in rice straw (4.5%) However, a more detailed analysis using Light Microscopy, Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) revealed major differences in anatomical characteristics, with the fiber in banana pseudo stem presenting

a tubular structure which would facilitate the movement of water within the stem (Li et al., 2010) It is not known if such a structure is what facilitates the process of chopping the stem with a knife as is done traditionally, usually by women But it would explain the high content of water in the stem of about 94%, the major nutritional constraint to banana pseudo stem would appear to be the low level of protein about 3-4% in DM (Floulkes et al.,1978) However, an unusual finding was reported presence of 3% of soluble sugars in the liquid fraction which means that almost half of the reported 6% of DM in the banana pseudo stem is present as soluble sugars (Dao Thi My Tien et al., 2010) These have not been identified but the fact that the pseudo stem ensiles readily the pH falling from 4.5 to

3 within 5 days, confirms that they are readily fermentable (Dao Thi My Tien et al., 2010)

Taro foliage (Colocasia esculenta) as the source of protein, as taro was found in

natural habitats where water is stored, near river banks, streams and ponds in Laos It was reported that the planted area was 11,335 ha with average root yield of 10.7 tonnes/ha (MAF, 2017) In the study reported by Kaensombath and Frankow-Lindberg (2012) the forage biomass yield at root harvest was 1,483 kg/ha of DM, provide 260 g/kg of protein; the tuber DM yield was 2,732 kg/ha

Taro leaves are rich in protein (about 20% in DM) with a balance of essential amino acid close to that in an “ideal” protein (Rodríguez et al., 2006) The petioles are rich in sugars which facilitate ensiling the combined leaves and petioles to give a feed with 14-15% CP in the DM (Malavanh et al., 2008; Giang et al., 2010; Hai et al., 2013) Many experiments have demonstrated that ensiled taro foliage can be fed as a source of protein for pigs (Toan and Preston, 2010; Chittavong et al., 2012; Kaensombath and Lindberg, 2012; Hang et al., 2015) The limitation to the use of taro foliage in diets for pigs is the presence of oxalates which form crystalline insoluble salts that cause irritation

in the mouth of pigs when the foliage is consumed fresh However, this problem can be resolved by ensiling the taro before feeding (Hang et al., 2011)

Probiotics and prebiotics, as legislation to forbid use of antibiotics as growth promoters is increasingly being enforced so as to prevent development of resistant strains

of organisms that are pathogenic to humans The two approaches to safeguarding animal health and/or improving productivity are to replace antibiotics with either beneficial microorganisms (probiotics) such as Lactobacilli and yeasts that enhance the normal microbial flora in the animals’ digestive system or with additives (prebiotics) that provide habitat for microbial communities in the form of support structures for biofilms, or specific nutrients that support the proliferation of beneficial micro-organisms In the

former category Saccharomyces cerevisiae and Lactobacillus spp have been effective

organisms in binding a wide range of mycotoxins (Gallo et al., 2015) In the latter category are compounds such as β-glucan that are present in the walls of cereals such as barley and rice, and of yeasts These appear to be released in natural processes such as occur in the alcoholic fermentation of barley and rice and subsequent distillation to give beer and rice wine

The byproducts from these processes such as brewers’ spent grains’ and rice

distiller soluble (“Hem” in Vietnam, “Khi Lao” in Laos and “Bar Rao” in Cambodia) fed

at low levels in the diet (4 to 5% as DM) were shown to protect cattle (Phanthavong et al., 2016; Sengsouly and Preston 2016; Binh et al., 2017) and goats (Binh et al., 2018) from HCN toxicity caused by cyanogenic glucosides present in foliage of “bitter” varieties of cassava

Biochar, the by-product from the carbonization of fibrous residues at high temperatures of 500-1000 °C was originally identified as an ameliorating agent in soils and as a vehicle for sequestering atmospheric carbon (Lehmann, 2007) with associated beneficial effects on crop and plant growth (Lehman and Joseph, 2015; Preston, 2015) In pigs and chickens, it has been shown to be effective as an agent to facilitate the degradation of phytotoxins and mycotoxins (Gallo et al., 2015; Prasai et al 2017), as well

as providing habitat that enhances activities of microbial communities (Leng, 2017)

2 AIMS AND OBJECTIVES OF THE STUDY

2.1 Aims of the thesis

The aims of present research was to investigate the utilization of local feed resources

as forage-based diets and supplementation of grains’ fermentation by-products as additive feed to develop feed and feeding practical management with improving growth performance for native Moo Lath pigs in rural smallholder farms of Laos

2.2 Objectives of the thesis

The objectives of the research was to determine a local available forage of banana pseudo stem and taro foliage as basal diet and grain by-products as supplement feeds on growth performance and reproduction of native Moo Lath pig in smallholder of Laos The specific objectives in each chapter was stated as bellows:

1) Paper 1 (Chapter 2): To determine the effect of replacing ensiled taro foliage with ensiled banana pseudo stem in different proportion on feed intake, nutrient digestibility and nitrogen retention for native Moo Lath pigs in Laos

2) Paper 2 (Chapter 3): To investigate the effect of a low concentration of rice distillers’ by-product or brewers’ grains on digestibility and nitrogen retention in native Moo Lath pigs fed ensiled taro foliage and ensiled banana pseudo-stem as forage-based diets

3) Paper 3 (Chapter 4): To continuously test with a low concentration of rice distillers’ by-product or brewers’ grains when they were similar affected on growth rate and feed conversion during pregnancy and lactation of native Moo Lath gilts and their progeny fed ensiled taro foliage and ensiled banana pseudo-stem as forage-based diets

4) Paper 4 (Chapter 5): To evaluate the effect of rice distillers’ by-product and biochar as additives to a forage-based diet on growing and feed conversion of native Moo Lath pigs in Laos

3 HYPOTHESES OF THE RESEARCH

The researches were hypothesis that ensiled taro foliage combined with banana pseudo stem could be used as forage-based diet and rice distillers’ by-product or brewers’ grains in term of the biochar could be potential source of local prebiotic/probiotic to be improve the growth performance and better support for reproductive performance during

1) Paper 1 (Chapter 2): Ensiled taro foliage as protein sources combined with ensiled banana pseudo stem will be contributed suitable inclusive in the diet supporting for digestibility and biological value and could be included as foliage based-diet improving growth performance for native Moo Lath pigs

2) Paper 2 (Chapter 3): Small amounts (4% of diet DM) of either brewers' grains or rice distillers' by-product (Khilao) supplemented in foliage based diets would support increased growth rate in local Moo Lath pigs

3) Paper 3 (Chapter 4): Small amounts (4% of diet DM) of either brewers' grains or rice distillers' by-product supplements would bring similar benefits during the pregnancy-lactation and progeny of native Moo Lath pig gilts

4) Paper 4 (Chapter 5): Supplementation of biochar in a forage-based diet would be affected on growth performance and feed conversion of native Moo Lath pigs and

to compare it with rice distillers’ by-product already shown to be effective as a prebiotic in diets of Moo Lath pigs

4 INNOVATION CONTRIBUTED OF THE DISSERTATION

The innovation of this dissertation is the use of low concentrations (4% of diet DM) of agro-industrial by-products such as brewers’ grains, rice distillers’ residues and addition of biochar (1% of diet DM) as additives feed that appear to act as “prebiotics”, enhancing the growth and feed conversion of indigenous Moo Lath pigs fed on local feed

resource of ensiled foliage of Taro (Colocasia esculenta) and banana pseudo-stem (Musa

spp) Rice distillers’ residue (Khilao) is a by-product of artisanal rice wine production

widely available in rural areas of countries in SE Asia Biochar is the residue after carbonization of rice husks in gasifier stoves used in rural households to produce gas for cooking The carbon in biochar is in close association with phenolic compounds making

it resistant to microbial oxidation, thus when recycled to soil in animal excreta, it will act

as a mechanism for sequestering atmospheric carbon

REFERENCE

Binh, P.L.T., Preston, T.R., Duong, K.N and Leng, R.A., 2017 A low concentration (4%

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CHAPTER 1 LITERATURE REVIEW 1.1 PIG PRODUCTION IN SMALLHOLDER OF LAOS

1.1.1 The role of pig production

The Lao PDR is tropical country and located in Southeast Asia The territory is situated in the Indochina peninsula, land covered 236,800 square kilometres, with human population about 6.7 million peoples, and a density of 27 persons per square kilometres for whole country(LPHC, 2015) Laos had a total gross domestic production (GDP) of 2,408 US$ per capita with GDP growth rate 7.02% (LSB, 2016) Around 67.1% of population are living in rural area and 72% are engaged in agriculture farming system

) LPHC, 2015), with contributed 17.23% of GDP, and from livestock are accounted 2.17%

(LSB, 2016(.

Livestock are the most important components in the Lao PDR with sales of livestock accounting for more than 50% of cash income in many upland and highland area (Knips, 2004) Pig production is a common activity to support livelihood in smallholders, most farm household in the region holding at least a few pigs However, smallholder farms are practice accounted for 86.5% of total pig production in 2017 (MAF, 2017) Around 64% of pig rising is for home consumption especially in cultural events, accumulation capital and less generated cash income (Stür et al., 2002)

1.1.2 Pig population and consumption

There are total number of pigs of 3.7 million heads in whole country, with local pigs are accounted of 3.2 million pigs (DLF, 2017) and approximately of 25% is derived from commercial farms, with remaining of 75% is arisen in smallholder farmers (Souriyasack, 2011) However, pig products are imported from outside of the country around 30% by 2017, particularly from Thailand (DLF, 2017) Pig production being trend

to increase surrounding the year from 2013-2016, but declined in 2017 (figure 1.1)

Figure 1.1 Number of pigs in Laos from 2013-2017; Sources: MAF (2010-2017)

Pig meats are most popular consumed by Lao people, as providing beneficial economy for farmers particularly for pig farming sector and smallholder rural pig production Pigs are numerous supplying demand of meat product for consumers around 58% which compared to other livestock species (MAF, 2017) Meat required to consume for Lao people is 57 kg/capita, with pork are 14.6 kg in 2017 and need to be consume around of 65 kg/capita (pork is around 16.8 kg/capita) by 2020 (MAF, 2017)

Table 1.1 Number of livestock products and meat consumption in 2017

No Livestock slaughter house No of animal

1.2 CURRENTLY TYPICAL PIG FARMING IN LAOS

Pig rearing system in Laos can be clarified into three main categories such as smallholder pig production (small scale), semi-intensive (medium scale) and commercial scale (large scale) farming, which similarly in southeast Asian country (Huynh et al., 2014)

1.2.1 Smallholder pig farming

In Laos PDR, smallholder pig farms are importance for livelihood activity of rural people, supplying meat as food security for household which provided protein meat for consumers and generate cash income for pig keepers (Blacksell et al., 2006; Phengsavanh, 2006; Stür et al., 2002) In the production stage, housing and nutrition management are poor condition that factor affect to growth rate, as low at 100 g/day in smallholder condition (Phengsavanh et al., 2010) In the studying by use stylo leave fed

to native pigs increased a growth rate upto 154-230 g/day (Keoboualapheth et al., 2003) Similar observed a growth rate of 155-193 g/day when fed cassava leaf silage supplemented in diets (Xaypha et al., 2007) However, supplement of soybean meal and ensiled taro in diet has better growth rate 340 to 400 g/day (Chittavong, 2012), as similarly that pig fed a more balanced diet they can growth up reach to 500 g/day (Keonouchanh et al., 2008) The productivities of gilts/sows are low with piglet mortality

is reported in high up to 30-50% (Phengsavanh and Stür, 2006; Phengsavanh et al.,2010; Phengvilaysouk et al., 2017). The nutritional deficiencies may arise despite feeding with local feeds are imbalanced (Chittavong et al., 2012), no any health care caused of disease infection (Kagira et al., 2010)

The feed resources are agricultural by-products such as rice bran, corn, cassava, rice distillers’ waste, edible grass and household scraps (Vongthilath and Blacksell, 1999), banana stem, taro and yams (Stür et al., 2002; Phengsavanh et al., 2010) Together with distiller’s waste and household scraps are provided for pigs in villages level (Osbjer, 2006) In this system, pig farmers are poor addition feeds feeding to pigs, with no protected from disease (no any vaccination, deworming and treated), with poor nutrients

in diet composition which factor affected on the growth performance and health Therefore, to overcome local pig productivities the approach to development of feeding system and possibility use the local available feed resources (Kumaresan et al., 2007)

The Moo Lath pigs are more commonly kept by smallholder pig farmers, it is characterized by a low body weight, a low growth rate and high capacity for fat deposit (Phengsavanh et al., 2011) There are four different native breeds distributed in different region of Laos that smallholder scale pig household holding in the area such as Moo chid, Moo Lath, Moo Hmong and Moo Deng, which preliminarily described the phenotype characteristic condition and reproductive performance properties (Keonouchanh et al.,

Table 1.2 Classification of phenotype characteristics and reproductive performance of native pigs distributed in smallholder farm conditions in Lao PDR

Phenotypes characteristic#

Size, ear type and face term

Small body size, small ear, short and directed

Small, short and directed ear, Straight face,

Larger ears and directed forward, Short and bent face

Large hanging ears, bent face

Coat colour

Black coat, while spot at legs or head

black coat, leg and front of face are white

Mostly black coa

Brown colour,

Distribution mostly Scattered in all

region of Laos

North and Lowland1

Northern area2 Southern

area3

Sources: Keonouchanh et al (2008), # data adapted from Oosterwijk et al (2003)

1 Moo Lath distributed mostly in northern province (Phongsaly, Louangprabang, Oudomxay, Xaysomboun and Vietiane province), some lowland provinces (Borikhamsay, Saravane and Savannakhet provinces); 2

Moo Hmong mostly kept in some province: Xienkhouang (Nonghad district); 3 Moo Deng arisen only in southern of Laos particularly in Champasack (Mounlapamok and Khongdistricts), well-adopted and crossbreed

Figure 1.2 Lao name - Moo Chid

(Moo Markadon or Moo Boua)

Figure 1.3 Lao name - Moo Lath

Figure 1.4 Lao name - Moo

Nonghad or Moo Hmong

Figure 1.5 Lao name - Moo Deng or Moo Berk

Sources: Keonouchanh et al (2008); Sivilai et al (2018)

In Cambodia, small scale pig farms raised 2 to 4 pigs that fattened during 8 to 12 months to reach marketable weight, fed a low quality of feed and low output, with un-control disease has been reported similarly (Borin, 2006) In the Philipines, small scale pig raising are higher than in Cambodia and Laos, as less than 10 heads to the slaughter house (Villar et al., 2002) In Vietnam, small-scale pig production accounts for 80% of the total production, farmers keep 1 to 2 sows and less than 10 fatteners, and produce piglets, finished fatteners or both production (Lemke, 2008) However, small scale farm is definite in Laos and Cambodia have less than 5 pigs in the household and higher number

of pigs raised in Philippines and Vietnam has less than 20 heads (Jones, 2002; La et al., 2002) In the reviews by Steinfeld (1998) revealed that nearly 70% of all pigs in the Laos, Vietnam, Cambodia and Philippines are raised in small-scale farms at household units In Laos, small scale pig production are sub-definite in three different category systems such

as free-scavenging, semi-scavenging and year-round confinement system (Phengsavanh

et al., 2011)

1.2.1.1 The free-scavenging pig

Pigs were allowed to scavenge freely for feed all the year round and small number

of pigs was raised 2 to 4 sows plus piglets In most villages, pigs were kept in simple

shelters, but in some villages, pigs simply stayed under dwellings, under rice storage

sheds or under trees Around 39% of households raised pigs in free scavenging systems

1.2.1.2 The semi-scavenging

Pig commonly kept in smallholder situation near population area, which farmers

raised pigs likely to perform a small family business system Farmers used native pigs combine with improved breeds 3 to 4 heads per households generally in the village with penned and are given improved feeds and accounts for 3% of all Lao pig production in this system (Vongthilath and Blacksell, 1999)

1.2.1.3 The year-round confinement

Pig is performed in accessible areas that close to the district center This system likely to produced semi-intensive pig production, because of farmers used largely numbers of exotic pig in a farm scale and fed concentrate feed that mixed with local basal diets The confinement systems are also provided regular vaccination and de-worming, with production is both piglets and growers but accounts for 1% in all Lao pig production (Vongthilath and Blacksell, 1999)

Smallholder pig production in Lao PDR is traditional practice by using native pig breeds, as a low input and also low output for farm households and associated generally the responsibility by women in all regions of Laos (ADB, 2001) The advantage of native pig breeds are known to have better adaptive capacities to local climatic conditions such

as high temperatures and high humidity (UNDP, 2012) It is perceived to subsist well that rely on scavenging for nutrition, hardy, resistant to disease and achieve early sexual maturity (Phengsavanh & Stür, 2006) However, the potential growth rate of native pigs

is markedly higher than reported by researchers, is a native pig (Moo Lath) could grow up

to 500 to 560 g/day based on the nutrient quality in pig diet (Keonouchanh et al., 2011; Phengsavanh & Stür, 2006) This indicates that low growth rates among native breeds are probably due to feed restriction rather than genetic potential

1.2.2 Semi-intensive pig production

Semi-intensive pig farming is definite as small family business farming system by raise pig including indigenous pig and cross breed pig This pig production primarily

based on market price for feed and products that can be also definite relatively high level

of inputs is required, housing material, feeds, veterinary products and labour Pig production is often the sole as a major source of income and farmers require management skills as well as financial capacities. Vongthilath and Blacksell (1999) perceived that generally, pig farmers are raised minimum of 3 to 6 heads including indigenous and improved breeds In this system, pig farming quite invested and economic benefits, due to farmers may involve the purchase of weaner pigs for fattening to sale, the farmers using commercial feed that relatively high cost (Stür et al., 2002) The pig keeping usually improved breeds such as Large White or Landrace and crossbreeds, with fed branches, leaves, crop residues, agricultural by-products or prepared feed because raise pigs for subsistence and commercial reasons, health management by vaccination and treatment

(Wilson, 2007) In around the city of Cambodia, a medium pig farm keeps 10-50 pigs and they can be a mix of production categories such as sows, piglets, and fatteners which comprising of feeds are homemade or commercial feed and operated to own rice mill and brewers rice wine (Borin, 2006)

However, Huynh et al (2014) reported that semi-intensive (medium scale pig production) in Laos, Cambodia, Philippines and Vietnam are produced 15% of total pig production and normally they kept pigs between 10 to 500 heads for fatteners and 5 to

100 heads for sows depending on the countries Small feed-mixing facility, house a husk milling are contributed in some region Pigs are kept in pens, with given commercial feed and vaccinations and biosecurity measures are applied with extreme caution (Villar et al., 2002; Steinfeld et al., 2006)

1.2.3 Commercial scale pig production

The commercial pig farms in Laos are the most distributed in the cities area which significantly located in central and southern parts of Laos as urbanization with high population demanding for pork Those pig farms are arisen as enterprise sectors under domestic investors and the typical commercial pig farms that belong to the CP Lao Company and Betago private sectors, in term of small medium producers Mostly pigs used are exotic breeds such as crossed bred of Large White, Landrace, Duroc Jersey and some of hybrids (Wilson, 2007) This farm are very well equipped, good management, and have a high productivity, with feeding is based on concentrate and bagged commercial feeds and some commercial pig farms are used local feedstuffs as diet in their

own formulation particularly for finishing pigs There are 572 commercial pig farms in whole country of Laos with total of 284,454 pigs There are raised 1,400 boars and 23,200 sows and produced piglets of 415,500-420,000 heads/year, which established lowland of Laos (MAF, 2017) In Cambodia, the exotic breeds are mostly used as Yorkshire and Landrace that kept in this system and supply almost of grandparent stock, breeding sows, and piglets (Borin, 2006) In the Philippines, large-scale farms hold 14.7% of the total breeding stock (Costales et al., 2006) In other hand, the commercial pig farms in Vietnam is privately owned and enterprise sectors, as involved in breeding herds, fattening, feed supply, slaughter, and processing (Jones, 2002; Drucker et al., 2006) Feeding based on concentrate and bagged commercial feeds, some are used local basal diet in their own formulation (La et al., 2002)

1.3 Feeds and feeding practical management in smallholder pig farms

1.3.1 Feeds derived from agricultural by-products

There are derived mainly from rice by-product (Oryza sativa) such as rice bran,

broken rice, polished rice and also maize and cassava root are a source of energy diet for pigs In most regions of Laos, smallholder pig farms are commonly used about 61-74% of rice bran in their pig keeping (Phengvilaysouk et al., 2017) Rice bran and broken rice trend to be available in almost of the year except for a short period of seasonal the new rice is harvested (Phengsavanh & Stür, 2006) The maize is one of the most important crops, which subjected to both in human consumption and also feeding for animals such

as pig and poultry feed (Phengsavanh et al., 2010) Less frequently used around 8 % of maize, depending on availability (Phengvilaysouk et al., 2017), Maize contains around 40-60 g/kg crude fat, 90-140 g crude protein, 0.2 g calcium and 2-3 g/Kg phosphorus However, some essential amino acids (EAA) such as lysine, threonine, isoleucine and tryptophan are limited (McDonald et al., 2011; Blair, 2007)

Cassava is traditional plant usually used for human consumption and as animal feed The leaves of cassava are also used for pig as protein sources and root is importance source of carbohydrate In the villages level was frequently used around 17% of cassava root, depending on seasonally availability (Phengvilaysouk et al., 2017) The root of cassava is very good source of energy, as content metabolizable energy (ME) of 3378 Kcal/kg, fiber 4.18% and crude protein 2.88% (NRC, 2012)

1.3.2 Green plant materials as feeds for pigs

The green plants including forage plants are alternative feed resources for sustainable pig production in tropical area These plants are counted for taro foliage,

banana pseudo stem, coco yams, thick head, paper mulberry and green amaranth, and

vegetarians such as pumpkin tops and sweet potato leaves are used for pigs (Phengsavanh

et al., 2010) The green feeds or vegetable matter in term of cropping and forest matter are traditionally collected from forest, river stream and fallow fields and several other herbs depending on local availability (Thorne, 2005; Phengsavanh & Stür, 2006). These green plants are a high fibre content and a relatively high content of crude protein (Leterme et al., 2005) Farmer used those of feedstuffs dependent on the traditional way such as cooking mostly by household, but not in commercial pig production or by the animal feed industry

1.3.3 Feeds derived from leftover materials

The using of rice distillers’ waste and household scraps are traditional knowledge

to use as feed for pigs Oosterwijk et al (2003) mentioned that combining distillers’ residues with energy-rich feeds such as rice bran (2 kg), broken rice (1 kg) and distillers’ residues (5-10 litters) are implemented by smallholder pig farms

In the feeding practical management, smallholder pig productions are encountered

to access in feed resources results in feed shortage, insufficient both in quantity and quality of feed that is factor affect to the productivity and growing )Thorne, 2005; Phengsavanh & Stür, 2008(. Smallholder pig raising are low input due to limited feed adequately, with pigs are un-penned that difficult for disease control, scavenging for food and very traditional management.

1.4 CONSTRAINTS AND OPPORTUNITY IN SMALLHOLDER FARMS

1.4.1 Main problem in smallholder pig production

 Poor nutrition is major constraints for pig production in smallholder condition and

it contributes to poor resistance, which in turn exacerbates the problems of infectious disease (Stür et al., 2002) Low quality of feed and lack of the availability resources are resulted in a low growth rates, low productivities of sows, and high mortality of piglets

 Poor practical management related on traditional methods, with poor feeding and

weaning has been identified as a major contributing factor to low growth (20 to 50 g/day) and high piglet mortality (30 to 50%) on smallholder pig farm (Phengsavanh & Stür, 2006)

 Poor market access in rural smallholder pig farms and limited access to high quality veterinary attention and effective vaccination services throughout the year Overall poor nutrition, poor practical management including breeding and carcass traits and disease are the major concern in smallholder pig production in Laos

1.4.2 Opportunity improvement of pig productivity

Increasing productivity of rural pig rearing system is required in further implementation, which satisfied both for producers and consumers There is also demand for good cuts of pork and good quality of meat to access to the market and specific consumers The improving approach is mainly focus on the several issues as follows:

1.4.2.1 Improving feeds, resources and rearing

They are many types of feed resources could be introduced to smallholder pig farmers to improve productivities Having an accessible feed sources enable farmers to house their pig, and also allows better management of feeding, breeding, farrowing and weaning of piglets in term of prevention of disease These improvements of productivities can be resulted increase in the output of household pig production.

1.4.2.2 Reduced piglet mortality

The penning of pigs will reduce the incidence of disease, and disease spread within a village, thus directly contributing to reduced mortality Farmers who raise pigs commercially may be willing to invest in vaccinations and treatment the parasites This could significantly increase the number of pigs and farmers would have products for sale

as satisfy for trader requirement as well as for consumers and also beneficially for pig producers

1.4.2.3 Improve feeding practical management

Traditional pig production however, with poor feed and high mortality has such a low output that it is very difficult for farmers to respond to the increased demand The strategy developed local pig feeds by using available feed resources Providing feeds to the pig in different stage of age such as diet for piglets, grower pigs, finisher pigs and farrowing stage This is willing to deal grower and finisher pigs as required by consumers

in north of Laos, while in central and south of Laos, people would be bought piglet and growers

1.4.2.4 Access to the marketable and consumers

The most pig production is derived from smallholders in rural villages and nearby the city but not invested like commercial farm Pig farms could be supplied regular, consistent of quality and price during the year The requirement of pig consumer is quite difference as depending on the traditional condition and depending on the area

1.5 ALTERNATIVE USE OF LOCAL FEED RESOURCES FOR PIGS

1.5.1 Taro foliage (Colocasia esculenta)

1.5.1.1 Resources and biomass yield

Taro is very easy to grow, naturally or by planting with very high biomass yield and re-growth capacity In Laos, there are area of taro and root planted totally 189,201 ha, with yield 14.78 ton/ha in 2016 (LSB, 2016), but slightly reduced in 2017 It is 11,335 ha

of planting area, with yield 10.71 ton/ha (MAF, 2017) Whilst, study that total leaf DM biomass yield was 1,483 kg/ha when harvested at 4 weeks, providing CP 260g/kg DM, Ash 145 g/kg, 206 g/kg DM, with average tuber DM yield was 2,732 kg/ha

(Kaensombath and Frankow-Lindberg, 2012) In Vietnam, biomass yield of taro was

estimated from 220 to 244 t/ha/year, providing 12 tons of DM and 2.4 to 2.5 of CP t/ha/year (Hang et al., 2015) Similar, results found that taro biomass yield ranged from

250 to 370 t/ha/year (Toan and Preston, 2010) Taro foliage can be harvested at 30 days interval throughout the year with biomass yield 250 t/ha/year of fresh matter (Ngo Huu Toan and Preston, 2007; Hang and Kien, 2012) In wet condition, taro can be harvested after 10 to 12 months, in dry land 12 to 15 months For the root/corm yield ranges from 5

to 6 t/ha, but a good crop on fertile soil is around 12 t/ha (Safo Kantaka, 2004)

1.5.1.2 Nutritional contents

A nutritional content in taro has been recognized differently dependent on the part

of the taro, species and method processing Taro foliage is a good source of protein as rich in the essential amino acids (Rodríguez et al., 2006) The leaves of taro are also rich

in vitamins and minerals such as thiamine, riboflavin, iron, phosphorus and zinc, and a very good source of vitamin B6, vitamin C, niacin, potassium, copper and manganese (Onwueme, 1999)

Table 1.3 Composition of taro plant in different parts of studying (% DM basis)

Du Thanh Hang and Preston., 2010

16.0 22.5 - 11.7 18.3 Chittavong et al., 2008

Ensiled taro leaves

18.3 25.9 - 8.3 - Pheng Buntha et al., 2008 20.2 19 - 11.6 13.2 Chittavong et al., 2008

Sources: Rodríguez et al (2006)

1.5.1.3 Oxalates contents

Oxalate is anti-nutritional factors in taro plant that occur in two form such as soluble oxalate and insoluble oxalate Soluble oxalate is usually form with monovalent ion such as sodium (Na+), potassium (K+) and ammonium (NH4+) Insoluble oxalate is forms with divalent ion with Ca2+, Fe2+, and Mg2+, which oxalate can bind with these minerals to form insoluble “calcium oxalate”, as it is precipitated in the kidney “kidney stone” and lead to kidney failure Oxalates can form non-absorbable insoluble salts with

Ca2+, Fe2+, and Mg2+, rendering these minerals unavailable (Savage et al., 2009)

Table 1.5 Oxalate contents in taro (total, soluble and insoluble oxalate)

Total Soluble Insoluble Sources Oxalate concentrate in leave or petiole of taro, mg/100g

Taro leave, mg/100g DM 2404-4416 83-1475 961-6259

Hang et al., 2011 Taro petiole, mg/100g DM 2021- 6342 142-2794 811-3613

Savage, 2006

Oxalate levels in 3 species of taro (Colocacia esculenta, Alocacia odera, Xanthosoma nigra)

Preston, 2010

1.5.2 Banana pseudo stem (Musa spp) by-product

1.5.2.1 Biomass yield and resources

Banana is a traditional plant cultivated widely for fruits and its production yields

is large quantities of forage biomass In Laos, banana tree has been grown extending to all parts of province and widely distributed in the forest as wild banana, particularly in mountain area There are totally planted area of 28,600 ha, with production capacity is 946.820 tons, with yielded of 41.89 t/ha in fresh matter (MAF, 2017) In the research, it has been estimated that there is a residual biomass yield of 13 to 20 tons DM/ha/year (Ffoulkes and Preston, 1978)

et al., 1978) Fibre content is high 50 to 70% DM for NDF and about 30-40% DM for ADF The energy digestibility for growing pigs is 44.7% and digestible energy is 7.4 MJ/Kg DM (Nguyen Nhut Xuan Dung et al., 2002)

Table 1.6 Nutrients content of banana stalk in fresh matter

Dry matter % as fed 5.1 9.8 7.2

Sources: Nguyen Nhut Xuan Dung et al (2002)

1.6 UTILIZATION OF FORAGE-BASED DIET FOR PIGS

1.6.1 Taro as protein sources for pigs

Taro (Colocasia esculenta) is traditionally forage that cultivated by farmers, it

also arises naturally in Laos, as well as in Vietnam and Cambodia Taro is a great potential animal feed in the tropics and subtropics, as a staple food for pigs and human It

is contained a high potential source of protein in pig diets (Toan and Preston, 2010; Hang

et al., 2015) The farmers used taro leave and corm for feeding to pigs through cooking them with rice bran, maize, broken rice and cassava roots Several species of taro plant can be ensiled easily without any addition substance (Rodríguez and Preston, 2009) Taro

is sources of amino acid closed to ideal protein with similar contents compare to soybean

meal (Rodríguez et al., 2006) Authors concluded that ensiled taro leaves are a protein source of high biological value for growing pigs (Hang et al., 2016) and it can be

contained up to 80% in pig diet (Rodríguez and Preston, 2009) Taro leaves are rich in protein around 21% to 26% of DM, while the petioles are rich in soluble carbohydrates (Hang and Preston, 2009)

1.6.2 Effect of taro foliage on apparent digestibility and N retention in pigs

The preliminary study by Rodríguez et al (2009) implied that the protein in fresh leave of new cocoyam has a high biological value at least equal to soybean meal, however, lower CP digestibility (61%) versus soybean meal (81%) in pig The concentrate of oxalate as anti-nutrition factor in fresh leaves of taro comprising high value has been reported about 1,560 mg/100 g DM (Savage and Dubois, 2006), the

are recommended for human or animal consumption (Hang et al., 2017) It may reasonable impressed palatability and negative effect on the feed intake and digestibility However, different processing technique of taro foliage could be reduced oxalate concentrate (Pheng Bountha et al., 2008; Hang and Preston, 2009) In this condition, ensiling of taro foliage could be alternative feasible applied for smallholder pig farmer practice Hang et al (2016) found that after ensiling the taro leave for 21 days, the concentrate of oxalated was reduced by 30% on leave alone and by 50% when petioles or molasses were added In other hand, ensiled taro leaves with molasses (Tiep et al., 2006)

or by combining them with the petioles (Hang and Preston, 2009) resulted in a considerable reduction in total oxalates The study on the ensiled new cocoyam offering

to the growing pig was increased in CP digestibility and N retention (Rodríguez et al., 2009) While, ensiled taro leaves or foliage (leave and stem) have been indicated to decline apparent digestibility of DM from 900 to 809 g/kg and crude protein from 816 to

595 g/kg, as foliage replaced soybean meal (Chittavong et al., 2008) Together, ensiled taro leaves replaced fish meal, maize and rice bran were reduced N retention from 19 to

17 g/day, but the biological value of the protein was the same on both diets at 86 and 87% (P>0.05) (Hang et al., 2016) Similarly, the feeding pig with taro silage has higher value for DM and OM digestibility (87.7 and 93.4%), but CP digestibility and N balance were worse (Pheng Buntha et al., 2008) In other study, the taro foliage could be combined with other forage protein substitutes improved feed quality, a comprising of ensiled taro foliage and ensiled mulberry leave fed a basal diet of rice bran for growing pig were higher CP digestibility in taro foliage with mulberry leave (71.1 %) as well as increased

in N intake and retention (Chhay Ty et al., 2010)

1.6.3 Effect of taro foliage on growth performance of pigs

Use of leave from topical tree and shrubs as protein source in pig diets is prospected to demonstrate the conventional protein requirement for pigs (NRC, 1998) The protein in the diet had the required balance of essential and non-essential amino acids, subsequently referred to as the ideal protein (Wang and Fuller, 1989) Tao foliage (leave and stem) in the form of ensiling has been used successfully in pig diets to replace

at least half the protein usually supplied as soybean and fish meal protein (Preston, 2006) The leave of taro indicated to contain an amino acid balance which responded to the study by Rodríguez et al (2006) presented that the balance of the first-limiting essential