determination of the most suitable live feed for stripped catfish (pangasianodon hypophthalmus) fries during the first 20 days posthatching

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIESDETERMINATION OF THE MOST SUITABLE LIVE FEED FOR STRIPPED CATFISH PANGASIANODON HYPOPHTHALMUS FRIES DURING THE FIRST 20 DAYS POST-

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES

DETERMINATION OF THE MOST SUITABLE LIVE FEED FOR STRIPPED CATFISH (PANGASIANODON HYPOPHTHALMUS) FRIES DURING THE

FIRST 20 DAYS POST-HATCHING

By HUYNH LE NGOC THU TRAM

A thesis submitted in partial fulfillment of the requirements for

the degree of Bachelor of Aquaculture

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES

DETERMINATION OF THE MOST SUITABLE LIVE FEED FOR STRIPPED CATFISH (PANGASIANODON HYPOPHTHALMUS) FRIES DURING THE

FIRST 20 DAYS POST-HATCHING

By HUYNH LE NGOC THU TRAM

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

Bachelor of science in Aquaculture

Supervisor Prof Dr.VU NGOC UT

Dr TRAN SUONG NGOC

I would like to thank the Directory of Can Tho University, the Management Board of the Department of Applied Hydrobiology - College of Aquaculture and Fisheries - Can Tho University for enabling me to study, laboratory assistance, technical support and research topics to complete the program

I wish to express my deep appreciation and sincere gratitude to my advisor Prof Dr.Vu Ngoc Ut and Tran Suong Ngoc (Department of Applied Hydrobiology, College of Aquaculture and Fisheries, Can Tho University) for advantage of the guidance, encouragement and valuable advice during the execution of graduation

I would like to thank to Ms Hien (rotifer room) was my guide in the rotifer culture to complete the experiment

Huynh Le Ngoc Thu Tram

This research was implemented in the fish hatchery of the College of Aquaculture and Fisheries, Can Tho University from June 2012 to December 2012 Two indoor experiments were conducted for duration of 20 days Tra catfish fries were nursed in 18 L plastic tanks at a density of 10 ind./L The first experiment was

designed to determine the most suitable feeding density of Rotifers (Brachionus

angularis) The experiment was randomly set up with 4 treatments, 3 replications

each Tra catfish fries were fed with different densities (3, 5, 8 and 11 ind./mL) ofrotifers only at the first 3 days then Moina was applied toward the end of experiment during 20 days In the second experiment, Tra catfish fries were fed with freshwater rotifers at different times after hatching (24h, 32h, 42h and 48h) corresponding to 4treatments with 3 replicates each At the end of experiments, all fries were weighed individually to calculate growth and survival rate The result showed that in the first experiment, the most suitable density of rotifers was 8 ind./mL that can improve the survival rate of fish up to 40.19% with the highest growth rate and were statisticallydifferent from other treatments (p <0.05) In the second experiment, the most appropriate start feeding to provide feed for the fries to avoid cannibalism and improve the survival rate of pre-fingerlings was 24h after hatching

List of contents

Contents

Acknowledgements i

Abstract ii

List of contents iii

List of tables iv

List of figures v

1 Chapter I Introduction 1

1.1 Background of the study 1

1.2 Objectives 1

1.3 Contents: 1

2 Chapter II Literature Review 2

2.1 Biological characteristics of Stripped catfish 2

2.1.1 Classification 2

2.1.2 Distribution 2

2.1.3 Morphological and physiological characteristics 2

2.1.4 Nutritional characteristics: 2

2.1.5 Status of Stripped catfish hatcheries in Vietnam 3

2.1.6 Status Stripped catfish culture of Vietnam and the world 3

2.2 Live food production and application in aquaculture 5

2.2.1 Rotifers 5

2.2.2 Water flea (Moina) 6

2.2.3 Application of live food production in aquaculture 6

3 Chapter III Materials and methods 7

3.1 Location and time 7

3.2 Materials 7

3.3 Experimental design 7

3.4 Data collection 9

4 Chapter IV Results and discussions 10

5 Chapter V Conclusions and recommendations 19

List of tables

Tables

Table 2.1 The chemical composition of Plankton (%) 5

Table 4.1 Water quality parameters during the experiment 1 11

Table 4.2 Mouth gape size of fish in 20 days during the experiment 1 12

Table 4.3 Result the length of the fish after 20 days during the experiment 1 13

Table 4.4 Result the weight of the fish after 20 days during the experiment 1 14

Table 4.5 Water quality parameters during the experiment 2 15

Table 4.6 Mouth gape size of fish in 20 days during the experiment 2 16

Table 4.7 Result the length of the fish after 20 days during the experiment 2 17

Table 4.8 Result the weight of the fish after 20 days during the experiment 2 18

List of Figures

Figures

Figure 3.1 Dimensions of the buccal apparatus of Cetropomus undecimalis 10Figure 4.1 Growth in length of fish in the first experiment 13Figure 4.2 Growth in weight of fish in the first experiment 14Figure 4.3 Survival rate of fish in all treatments after 20 days in the first experiment15Figure 4.4: Growth in length of fish in the second experiment 17Figure 4.5 Growth of fish in weight in the second experiment 18Figure 4.6 Survival rate of fish in all treatments after 20 days in the second experiment 19

CHAPTER I INTRODUCTION 1.1 Background of the study:

Stripped catfish (Pangasianodon hypophthalmus), also known as “Tra catfish”

or sutchi catfish, in the Mekong Delta of Vietnam, is considered as important potential aquaculture because of its easy rearing, fast growing and high economic value Stripped catfish culture has been developed in recent years with reported export value nearly 980 thousand US$ in 2007 (VASEP 2008) Researchers predict that friesdemand increases day by day resulting in increasing catfish hatchery In 1981, the Research Institute for Aquaculture No.2 and Can tho University began breeding trials with wild catfish In the 1980s, nursery survival rates of stripped catfish were very low (<5%) In Vietnam, early researchers supposed that newly hatched stripped catfish were initially too small to rear in earthen ponds High mortality rates caused by

cannibalism and bacterial infection (Aeromonas hydrophila) are – problems rearing

hatchlings at high densities Among phases of fish development, early larval stages are generally considered as critical stage During early stages of the fish larvae, natural

food such as rotifers, water fleas (Moina and Daphnia) and other tiny organisms are

very important as initial feed for larvae Using live feed for the larvae are most essential because the fish larvae are too small mouth size and have no complete developed digestive tract, especially their digestive enzymes to feed on pellets during first few days of their life Use of live feed significantly improved fry survival rates to 60-70% The report determined that live feed size should be suitable for each different stage of catfish (Hung 2000) The success in the nursery production of fish fingerling

is largely dependent on the availability of suitable live food for feeding fish larvae, fry, and fingerling

1.2 Objectives:

To investigate the application of live feed during the first 20 days of rearing periods to improve survival rate and production of the stripped catfish fries from hatching to pre-juveniles stages

1.3 Contents:

- Determination of the most suitable density of rotifers fed to Tra catfish fries

- Determination of the most suitable start feeding rotifers to fish fries after hatching

CHAPTER II LITERATURE REVIEW

2.1 Biological characteristics of Stripped catfish:

to Pangasius, especially the most two popular species are stripped catfish

(Pangasianodon hypophthalmus) and basa catfish (Pangasius bocorti).

2.1.3 Morphological and physiological characteristics:

Stripped catfish have a terminal mouth, long body, gray back, silver tummy, wide mouth, relatively large eyes, presented adipose fin, dorsal fin far forward with one or two spines and, 8–9 pelvic fin rays separate, anal fin with 26 – 46 rays, vertebrae 39 - 52 Stripped catfish can live well in high organic matter environment, freshwater or brackish water, low dissolve oxygen level, high density Besides, they have air-breathing organs and are obligate air breathers (Thanh and Kiem, 2009)

2.1.4 Nutritional characteristics:

Stripped catfish are cannibalism because they feed each other when they end yolk and they continue to eat each other if they do not feed fully and timely To avoid cannibalism in the incubation tanks, they should be quickly transferred to the pond or feed on time During nursery period, they eat phytoplankton and small sized artificial feed (Nhi, 2005)

In the absence of preferred food, fish may use compulsory food such as detritus and roots of aquatic plants, vegetables and food of animal origin such as shrimp, crabs, insects, snails and fish In culture ponds, they have ability to adapt many different types of food such as homemade food, industrial food, rice-bran, vegetable (Nhi,2005)

2.1.5 Status of Stripped catfish hatcheries in Vietnam:

The first artificial reproduction of stripped catfish was achieved in Thailand in

1959 and has since expanded throughout Southeast Asia (Boonbrahm, 1959; cited by Cacot 1999) Since then, it has been done in Indonesia in 1981(Hardjamulia, 1981; cited by Cacot 1999) and Malaysia in 1983 (Thalathiah, 1983; cited by Cacot 1999)

In Vietnam, stripped catfish culture was traditionally established in the region from 1960s that seed sources used from the wild Since 1978, various institutions have undertaken research on artificial reproduction of stripped catfish These include the Fisheries Faculty, University of Agriculture No 4, Thu Duc, Ho Chi Minh City, in cooperation with Long Dinh Agriculture Vocational School, Tien Giang province The first fries were produced in 1979 The Research Institute for Aquaculture No.2 (RIA 2) and Can Tho University, both began induced spawning trials with wild catfish in 1981

(Trong, 2002) In the 1980s, nursery survival rates of P hypophthalmus were very low (<5%) due to cannibalism and bacterial infection (Aeromonas hydrophila) Particular

farming of stripped catfish has become highly developed since the closing of the lifecycle in 1996 and the development of a commercial hatchery sector from 1998 onwards Now, fry survival rates are 60-70 percent and nursery survival rates were significantly improved by using feed and releasing hatchlings into earthen ponds just prior to yolk sac absorption within 20-24 hours Thus, natural feeds are immediately available when yolk sac absorption is complete In addition, fries have enough space to avoid cannibalism (Hung, 2000) Since then, the seed production of striped catfish has been increased rapidly

In the Mekong Delta, there were 93 hatcheries of stripped catfish and average total area were about 8,303 m2 at the end of 2007 and the beginning 2008, mostly located in Dong Thap and An Giang provinces In addition, the average capacity of hatcheries was 818.3 million hatchling per year (Sinh, 2007)

2.1.6 Status of stripped catfish culture in the world and Vietnam:

According to FAO in 2007, average annual rate of aquaculture from 1998 to

2007 was 7.7% including more than 50% freshwater fishes Asia accounts for 88.5% yields of the world China was the largest country which contributes about 62.4% yields and 45.5% value in 2007 (FAO, 2007) In Cambodia, stripped catfish was 98%

in catfish species and more than 50% total yields in the country In Thailand, there was more than 50% stripped catfish farm in 8 provinces Malaysia, Indonesia have been effective in stripped catfish culture from the 1970s to the 1980s (Institute of Economic and fisheries planning Ho Chi Minh City, 2006)

In Vietnam, in the periods of 1998 to 2007, the total area under culture increased six times, about 6,000 ha (Dung, 2008) Farm price of catfish fluctuated in the range of 15,000 – 18,000 VND (~ 0.78-1.00 USD) per kg while the price of exported catfish fillets was around 2.3 USD/kg during 1997-2009 Annual commercial production of stripped catfish increased 45 times over this period, from 22,500 tonnes

to more than 1,000,000 tonnes The volume of exported Tra fillets sharp jumped more than 55 times over this period from 7,000 tonnes to 386,870 tones, and export values increased 50 times, from 19.7 million US$ to 979,036 million US$ Total production

of Tra in 2008 was estimated about 1.2 million tonnes, and the total production of exported fillets was 650,000 tonnes, with a total export value of approximately 1.45 billion US$ Striped catfish contributed 32% of total fisheries export value (Dung, 2008) Now Stripped catfish is exported to over 80 countries in the world including several in Europe (especially Poland and Spain), Asian countries, Mexico, Australia, the United States of America, and the Middle East New markets such as Russia are emerging (FAO, 2012)

2.2 Live food production and application in aquaculture:

2.2.1 Rotifers:

Japanese researchers realized that rotifers could be considered as a suitable live food for the early larval stages of marine fish Using rotifers in the commercial

hatchery operations of the red sea bream (Pagrus major) is successful and encouraged

investigations in the development of mass culture techniques of rotifers Twenty-five years after the first use of rotifers fed larviculture, some culture techniques for rotifers intensive production is applied worldwide The availability of large quantities of live food source has contributed to the successful hatchery production of more than 60

marine finfish species and 18 species of crustaceans Rotifers (Brachionus plicalitis)

are suitable food for Penaeidae and marine fishes Beside, Rotifers also fed for fry of marine fish in many countries such as: Japan, Taiwan, and Thailand… Rotifers are a manifold organism, tolerance to a wide range of environmental conditions, high reproduction rate (0.7-1.4 offspring.female-1.day-1) Moreover, their small size (around 0.1–0.5 mm long) and slow swimming velocity make them a suitable prey for fish larvae that have just resorbed their yolk sac However, the greatest potential for

densities, the animals reproduce rapidly thus contribute to the gradual increase of large quantities of live food in a very short time Last, the filter-feeding nature of the rotifers facilitates the inclusion into their body tissues of specific nutrients essential for the larval predators (i.e through bioencapsulation) (Hien, 2009)

Table 2.1 The chemical composition of zooplankton (%)

2.2.2 Water flea (Moina):

Water flea (Moina) also belongs to the Cladocera They thrive in ponds and reservoirs but primarily inhabit temporary ponds or ditches The period to reach reproductive maturity takes four to five days at 26°C At maturity, clear sexual dimorphic characteristics can be observed in the size of the animals and the antennules morphology Males (0.6-0.9 mm) are smaller than females (1.0-1.5 mm) and have long graspers, which are used for holding the female during copulation Sexually mature females carry only two eggs enclosed in an ephippium that is part of the dorsal exoskeleton They are smaller size than Daphnia, with higher protein content, and of comparable economic value Produced biomass is successfully used in the larviculture

of rainbow trout, salmon, striped bass and by tropical fish hobbyists who also use it in

a frozen form to feed over sixty fresh and salt-water fish varieties The partial

replacement of Artemia by Moina micrura was also reported to have a positive effect during the larviculture of the freshwater prawn (Macrobrachium rosenbergii) (Alam,

1992)

2.2.3 Application of live food production in aquaculture:

According to Watanabe et al (1983), rotifers can been riched using 7 ml and 15

ml of cod liver oil per 40l and 100l respectively, for 12 h every night with oxygen levels kept at 4 - 7 mgl-1 all through the period On the other hand, Lubzens et al (1989) maintained that in order to ensure adequate amounts of essential lipids, rotifers either must be enriched with appropriate algae or emulsified fresh oil Furthermore, Cruz et al (1999) reported best larval growth and survival by enriching rotifers with powersh-fish oil, containing a high level of Highly Unsaturated Fatty Acid (HUFA) 22; 6n-3 in the red porgy (Pagrus pagrus) larvae According to Aragao et al.540 Afr J Biotechnol (2004), feeding rotifers in enriched algae will increase the free Amino Acid (FAA) content of the rotifers They enriched the rotifers for 24 hrs in a microalga medium Enrichment of rotifer with HUFA before using them as live food appears to increase growth and survival of a variety of fish larvae (Lubzens et al., 2001)

According to Ludwig (1994), the optimum feeding rates for most fish larvae on rotifers have been determined that 20ml-1 of rotifers added to the tank culture of the sunshine bass, Moina spp was ideal for growth and survival of the larvae He obtained 48% survival rate by 27 days Estimates suggest that one red seabream larva requires 12,000-15,000 rotifers over 25 days until it reaches 10 mm in length (Kafuku and Ikenoue, 1983) Studied were the fuctional responses from hatching to 6 weeks of age

of whitefish (Chirostoma riojai) larvae that was offered selected Rotifers (Brachionus rotundiformis and B rubens) and Cladocerans (Moina macrocopa and Ceriodaphnia dubia) The experiments were conducted with different between initial and final zooplankton density represented prey comsumption such as: density of Rotifers (0.5, 1,

2, 4, 8 and 16 individual ml-1) and density of Cladocerans (0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 4.8 and 6.4 individual ml-1) Results showed that C riojai larvae consumed more zooplankton with increase prey availability; above a certain prey density (8 - 16 individual ml-1 in Rotifers and 3.2 – 6.4 individual ml-1 in Cladocerans) consumption rate tended to stabilize in most trials (S Nandini, 2004)

The experiments were conducted at duration of 30 days with density of 2.5 fry/L Trieu (2008) evaluated the the effects of different live feed diets on acceptability, growth and survival rate of the fries Whisker sheatfish fries were fed

with 4 types of feed including oligochaetes (Tubifex), waterflea (Moina), Artermia

nauplii and a combination of Moina and Tubifex The results showed that the most preferable live feeds for Whisker sheatfish fries were Tubifex or the combination of Moina and Tubifex After 30 days of culture, growth and survival rates of fish in

- Microscope, thermometer, chemical test kits for pH, NO2-, TAN

- Sources of Tra catfish fries: 20 hours after hatching fries were obtained from local hatcheries in Thot Not and Phung Hiep

- Freshwater rotifers (Brachionus angularis) were provided from the live food

production Laboratory, Department of Applied Hydrobiology, College Of Aquaculture and Fisheries

- Water flea (Moina sp.) was purchased from an ornamental fish store Before feeding,

Moina were washed with clean water and filtered through the mesh of 500 μm and washed with formalin solution of 50 mg /L

3.3 Experimental design:

The two experiments were designed with 4 treatments and 3 replications each The experiments were conducted for duration of 20 days Tra catfish fries were stocked in a 20 L bucket system with a volume of 18L at a density of 10 ind./L

3.3.1 Experiment 1: Determination of the most suitable density of rotifers fed to fish

fries

In this experiment fish were fed with different densities of rotifers in the first 3 days and then Moina was applied toward the end of experiment Four treatments were set up as following:

Treatment I: 3 rotifers/ml + successive 17 days with 5 moina/mL

Treatment II: 5 rotifers/ml + successive 17 days with 5 moina/mL (control)

Treatment III: 8 rotifers/ml + successive 17 days with 5 moina/mL

Treatment IV: 11 rotifers/ml+ successive 17 days with 5 moina/mL