comparing different methods to determine digestibility of snakehead (channa striata) juvenile

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES COMPARING DIFFERENT METHODS TO DETERMINE DIGESTIBILITY OF SNAKEHEAD Channa Striata JUVENILE BY NGUYEN THI THU NGAN A thesis su

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES

COMPARING DIFFERENT METHODS TO DETERMINE

DIGESTIBILITY OF SNAKEHEAD (Channa Striata) JUVENILE

BY

NGUYEN THI THU NGAN

A thesis submitted in partial fulfillment of the requirements for the degree of

Bachelor of S cience in Aquaculture

Can Tho, January 16, 2013

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CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES

COMPARING DIFFERENT METHODS TO DETERMINE DIGESTIBILITY

OF SNAKEHEAD (Channa Striata) JUVENILE

BY NGUYEN THI THU NGAN

A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor

of Science inAquaculture

Supervisor Ass Prof Dr TRAN THI THANH HIEN

Can Tho, January 16, 2013

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Acknowledgements

I wish to express my deep appreciation and sincere gratitude to my advisor Ass.Prof Dr Tran Thi Thanh Hien for her constant guidance and also good advises in during the time

I did these experiments and wrote thesis

The second thing I want to send nice messages to Mss Ngo Minh Dung and Mss Tran

Le Cam Tu who transfer to me all of cultural professional knowledge when I cultured snakehead in wet lab 3 or analyzed in the nutritional laboratory

Thanks to students of advanced aquaculture course 34, Aquaculture A1 course 35, and Fisheries management course 35 who was enthusiastic to help me finish this thesis Finally, thanks my family and also relatives make all of good things from finance to spirit help me strong during time I did it

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Abstract

In this study, a series of experiment was done to compare different fecal-collection methods and digestibility of some ingredients of snakehead A reference diet was fed 2 hours interval on 24 hours to find down what time was appropriate for collecting feces

in the next experiment and defined dry matter and protein digestibility of snakehead by settling technique No significant effect between groups of digestibility through 24 hours and time space from eight and ten hours was appropriate for applying three different methods (settling, dissection, and stripping) Stripping was ineffective in this case Dissection method was also assessed Dry matter and protein digestibility of this method were lower than those on settling method Therefore, settling was chosen as an appropriate method to determine dry matter and protein digestibility of test ingredient mixing with a control diet following 30:70 on ratio Ingredients included fishmeal, soybean meal, meat bone meal and blood meal The results showed that the diet which was made from fish meal was the best protein digestibility percentage (93.63±0.62), and the lowest one was meat bone meal (88.93 ± 0.58%) Soybean meal and blood meal were similar, 91.27 ± 0.58%, and 91.23±0.93%, respectively In digestibility of ingredients, fish meal was also the best one with 85.75± 1.90% on value, following by soybean meal (69.73 ± 2.3%), and lowest one being meat bone meal (52.28 ± 1.73%) In conclusion, some ingredients with animal protein sources were digested better than plant origin, except meat bone meal

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Table of Contents

CHAPTER I INTRODUCTION 1

1.1 Background 1

1.2 Research objectives 1

1.3 Research contents 1

CHAPTER II LITERTURE REVIEW 2

2.1 Characteristics of snakehead 2

2.1.1 Classification 2

2.1.2 Biology characteristics 3

2.1.3 Nutrition characteristics 3

2.2 Study on on fecal collection and digestibility of some ingredients for fish 3

CHAPTER III RESEARCH METHODOLOGY 7

3.1 Experimental site and period 7

3.2 Experimental fish 7

3.3 Experimental facilities 7

3.3.1 Facilities 7

3.3.2 Experimental feed 7

3.4 Digestible series of experiments 8

3.4.1 Experiment 1: Detection appropriate time for collecting feces 8

3.4.2 Experiment 2: Determination of appropriate fecal collection method for digestibility of snakehead 8

3.4.2 Experiment 3: Determination of digestibility of feed ingredients for snakehead 12

3.5 Sampling and data analysis methods 14

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CHAPTER IV RESULTS AND DISCUSSION 16

4.1 Environmental conditions 16

4.2 Comparison of fecal quantities and ADC settlement periods 17

4.3 Comparing three fecal- collection methods 18

4.4 Diets digestibility 19

4.5 Ingredients digestibility 19

CHAPTER V CONCLUSION AND RECOMMENDATION 22

5.1 Conclusion 22

5.2 Recommendation 22

Reference list 22

Appendix 25

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List of tables

Table 3.1: Chemical composition of experimental ingredients 8

Table 3.2: Table for predicted fecal-collection time 11

Table 3.3 Pellet – feed from mixing reference diet and ingredients 13

Table 4.1: Environmental condition of experiment 16

Table 4.2: The ADCs for three methods 18

Table 4.3: Diet digestibility of reference and treatment 19

Table 4.4: Digestibility of some ingredients 20

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List of figures

Figure 3.1: Settling system 9

Figure 3.2 Stripping method 10

Figure 3.3 The structure of an intestine 10

Figure 3.4 Pellet feed after mixing 12

Figure 4.1: Dry weight and ADCs of snakehead on two hours interval 17

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CHAPTER I INTRODUCTION 1.1 Background

In recent year, aquaculture is becoming majority in the Mekong Delta where national economy can be improved and developed through domestic consumption and export to many countries in the world The area for culturing aquaculture estimates 737,600 ha with production 1,869,484 tones, which accounted for over 73% the production of the country (General Statistic Office, 2010) The main cultured species are Tra catfish,

shrimp, snakehead, and red tilapia Snakehead (Channa striata) is one of the new species

which are cultured recently, but it is becoming potential aquaculture, which is production get 40,000 tons in 2011 and some households can get 14tons per year The average feed cost which typically comprises over 80% of the total variable production cost in the country (Tran Thi Thanh Hien and Nguyen Anh Tuan 2009) However, scientifically, there has not been any study on digestibility of this kind of species Practically, research

on the digestibility is also essential to cost effective conduction of aquacultural diets and

it contributed to establish feed formula for aquatic animals (Glencross et al 2007)

However, researches showed that the digestibility of feed ingredients was influenced by fecal- collection methods (Weatherup and Mc Cracken 1998; Vandenberg and de la Noue

2001; Glencross et al 2005) Therefore, the study aimed to detect the appropriate fecal

collection methods and determine the protein digestibility of different feed ingredients on

snakehead (Channa striata) juvenile

1.2 Research objectives

Detecting the appropriate fecal collection to determine the digestibility of some ingredients of snakehead juvenile in order to determine the protein digestibility of this species

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CHAPTER II LITERTURE REVIEW 2.1 Characteristics of snakehead

2.1.1 Classification

Channidea is the family of snakehead, including 2 genuses: one genus is Channa, lived in

Asia and other is Parachana, lived mostly in Africa There are 30 species of snakehead

today in the world, 5 species distributed in Vietnam and some Asia countries According

to Rainboth (1996), snakehead belongs to:

Order: Perciformers

Family: Channaidae (Ophiocephalidae)

Genus: Channa (Ophiocephalus)

Species: Channa striata

Some sneakhead species lived in Mekong Delta:

- Snakehead murrel (Channa striata)

- Dwarf snakehead (Channa gachua)

- Giant sneakhead (Channa micropeltes)

- Splendid snakehead (Channa lucius )

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2.1.2 Biology characteristics

According to Duong Nhut Long (2003), snakehead is abundant in rice fields, rivers, canal and lagoon It can adapt with the environment which is low oxygen, high turbidity and high temperature (over 300C) in freshwater and brackish water (8-12‰)

Snakehead is likely to live in where there have much ceratophyllum demersum, aquatic plants, and a mass of duck weed There are good places for snakehead to hide for prey These elongated and predatory fish are distinguished by a long dorsal fin, large mouth and shiny teeth The fish have short gullet, thick wall, and wrinkle inside gullet The big stomach is likely Y shape Observing digestive duct, it contains 63.01% of fish, 35.94%

of prawn, 1.03% of frog, and 0.02% of insects and organic matter

2.1.3 Nutrition characteristics

According to Duong Nhut Long (2003), snakehead use yolk for nutrition source during first 3 days after hatching and yeast, egg custard and power feed were the next chosen feed for dry duration After 5-7 days, snakehead can choose Moina, Daphnia, tubifex, or chironomid The juvenile eats likely with superworm and muckworm When becoming adult fish, they are good prey, mainly diets are shrimp, fish on small size in nature or pellet feed in commercial pond

2.2 Study on fecal collection and digestibility of some ingredients for fish

A research on effects of protein and energy ratio on fingerling snakehead (Channa

striata) conducted by K Samantary and S.S Mohanty (1997) Fingerlings on 12 ± 2g

was used with labolatory – made brown fish meal being a major source of protein in all the test diet which was fed 3% on body weight per day There are four protein levels and three energy levels at each protein level were used The result showed that 40% crude protein diets with 90.9 mg protein per kcal of digestible energy were the best result for highest growth and 45% crude protein diets with 93.8 mg per kcal on P/E ratio were lower result

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Indirect technique through inert marker is used popularly in aquaculture and terrestrial animal According to Tran Thi Thanh Hien (2004), the characteristic of marker is: (1) the speed of movement like as nutrient, (2) indigestibility and solubility in water, (3) no affecting digestibility and absorption of nutrients Because the inert markers do not affect digestibility and absorption of nutrients, the rate of marker in feed and feces is the digestibility of feed Some markers are used for research, namely, Cr2O3, HROM, HRA,

Cs137, Cr51 One of them, Cr2O3 is used mostly popular with the rate between feed and marker 0.5 – 1%

The research of Sales and Britz (2001) compared the use of 3 markers including: Chromic oxide, acid-insoluble ash (AIA) and crude fiber in South Africa abalone

(Haliotis midae L.) feed Results showed that AIA was the only marker that yielded

consistence realistic apparent digestibility coefficients (ADCs), the amount of Cr2O3 and crude fiber in feces was equal or lower than in feed, causing negative result Therefore,

Cr2O3 was used popularly marker in the research about digestibility of aquatic animal but not in mollusk as abalone

Beside, fecal-collection was divided into 2 groups: (1) direct technique: using gentle pressure contact to abdomen of fish to expel feces ( Nose, 1960), using tool to suck feces out of intestine or cutting final part of intestine to take feces (Windell, 1978) These above methods had disadvantages including: the feces had mixed with unabsorbed feed, digestible enzyme, urine, and death sock fish (2) fecal-collection in culture system to determine the digestibility of feed was more accuracy and reduced cons from direct technique, researchers applied fecal collection by culturing fish in

water Two mail methods are settling and continuous methods (Guillaume et al 1999)

Stripping method was applied popularly in many kinds of fish: white salmon fish

(Oncohynchus tshawytscha) grouper, Morone saxatilis x Monrone chrysops (Sullivan and Reigh 1995) and Sciaenops ocellatus L., (Gaylor and Gatlin 1996) The advantage of this method was that it could be repetition in experiment However, Hajen et al (1993)

showed that this repletion could make fish shock and reduce apparent digestibility

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coefficient (ADC) Beside, expelling feed suddenly in anaesthetized situation, it could encourage fish spawn unexpected (cited by Weatherup and Mc Cracken, 1998)

The research of Amirkolaie et al (2005) compared between 2 indirect techniques was

that fecal collection way of Choubert and settling method on tilapia The system of Choubert with mesh size was 1 mm and continuously collected, discharge water from the tank would lead to metal layer to separate feces and water The feces were hold on metal tray The settling tank is commercial tans Aqua Optima with 170ml of volume and 44cm

of height with diameter 24.5 cm There was the tube, connecting with fecal containers, which kept cool by ice for prevent of bacterial infection in collecting time As a result, water in the tanks had just moved a little which gave correct result and collected feces was higher than continuous method

Hien et al (2009) research on Tra catfish, determine the digestibility of some ingredients

was significant for research nutrition of fish The results of research could help to find down the material, which fish could digest well to improve the efficient of culturing of fish Therefore, there were many kinds of research about digestibility, especially, the digestibility of material in different fish

According to Tran Thi Thanh Hien (2004), the amount of fiber in feed could highly affect

to the digestibility of feed of aquatic animal Fiber could increase the speed of feed through digestive system so it could increase amount of intake feed and made slow

growth of aquatic animal It is relevant with a research of Umesh et al (1994) about digestibility of protein and dry matter from Spirulina platensis algae by common carp (Cyprinus carpio) The experiment was conducted with one control and nine treatments with adding Spirulina platensis algae with increase amount from 10-90% in formulated

feed The diets with adding algae were increase in protein and reduction on fiber value A result was that the dry matter digestibility was lower in control than in treatment They checked the result among group of treatments that the digestibility increased when the amount of algae in treatments went up It meant that digestibility was inversely proportional with the amount of fiber in feed The protein digestibility also increased in

The research of ingredient digestibility showed that the amount of ingredients mixed with feed was usually 30% of control and 70% of treatments However, some results convinced that the quantity of mixed material did not affect ingredient digestibility Kim

et al (2006) studied about the digestibility of haddock (Melanogrammus auglefinus L.),

when changing the amount of tested material to herring fish meal in experimental diet with quantity was about 10%, 20%, 30%, 40% and 50% A result showed that protein and energy digestibility among treatments was highly significant difference with 10-15% amount of herring meal Protein and energy digestibility with the average amount of herring fishmeal among treatments were 94.0% and 95.5%

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CHAPTER III RESEARCH METHODOLOGY 3.1 Experimental site and period

The study was conducted from June/1/2012 to December/15/2012 The experimental diets formulated in the laboratory in Department of nutrition and products processing, college of Aquaculture and Fisheries, Can Tho University

3.2 Experimental fish

All of snakeheads (Channa striata) used in three experiment was 120g/individual in size

The snakehead fishes were bought from farmers in Can Tho city

The experimental fish, which was healthy, without graze fin, no infection with disease Those fish fed different diets and tamed with the experimental condition

3.3 Experimental facilities

3.3.1 Facilities

Experiment conducted with six settling tanks (170L) These tanks designed as rounded tanks with conical bottom, which had a valve in each to avoid the feces following the flow going out and connected with composite fecal settling bottle to collect the feces for experiment In addition, these tanks used flowing out water system to be clean water and slightly aeration to ensure snakehead having good condition to live

3.3.2 Experimental feed

The formulated feed (45% crude protein) used in this experiment which was sinking in the tanks; it is based on a protein and energy ratio of snakehead of Mohanty and Samantaray (1997) The main ingredients contained fishmeal, soya meal, wheat flour, vitamin, mineral, oil, adhesive substance The feed should be stored in refrigerator

(%)

Protein (%)

Lipid (%)

Mineral (%)

Fiber (%)

c Experimental design

Fish fed seven day prior to make acclimation with cultural condition All feces were collected on eighth day, feces analyzed, dry matter and protein digestibility for control diet( 45% crude protein) was calculated and compared with feces collected every 2 hours after feeding (2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 hours)

During acclimation period, fish fed once a day at 8a.m by hand The quantity of feed depended on demand of fish After feeding 1 hour, tanks were cleaned by taking uneaten feed out

3.4.2 Experiment 2: Determination of appropriate fecal collection method for digestibility of snakehead

a Experimental fish and feed

The fish which was used in experiment 2 was also used in experiment 1

Experimental fish: reference diet mixed with chromic oxide 1% in weight

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b Experimental design

The experiment was conducted randomly three treatments for three fecal collection methods: stripping, dissection, and settlement (three replications per treatment) Six conical tanks used for this experiment which three used for settlement and three for striping method

- Treatment 1: settling method, the snakehead stocked 45 individuals in three composite settling tanks (170L), appropriately 88inds/m3

- Treatment 2: striping method, the snakehead stocked 45 individuals in three composite tanks (170 L), appropriately 88ind/m3

- Treatment 3: dissection method, killing all of fish of treatment 1 and treatment 2

Figure 3.1: Settling system