THA/75/012/WP 11 FEEDS FOR CATFISH (Clarias batrachus Linn.) FRY CONTENTS

by

Samran Dhamrongrat and Prasit Kasesunchi

Translated from Thai to English under the Programme for the Development of Pond Management Techniques and Disease Control (DoF - UNDP/FAO THA/75/012) Thailand

National Inland Fisheries Institute
Bangkok, Thailand
1981

PREFACE

The “Programme for the Development of Pond Management Techniques and Disease Control (THA/75/012)” was implemented in Thailand during 1979–82 as a joint project by the Department of Fisheries (DoF) and UNDP/FAO. The purpose of the project was to improve DoF support services for Clarias farming through strengthening:

1. the skills of Fisheries staff in aquaculture disciplines such as disease diagnosis and treatment, pond management and extension,

2. the research on solutions for problematical aspects of Clraias culture,

3. the system of relaying problems from the farms to DoF and of transferring improved technologies, and

4. the equipment and facility base of DoF for working on aquaculture problems.

Although the UNDP/FAO participation was structured terminate in August 1981, DoF committed continuation of the project to at least August 1982.

This report is one of several Working Papers prepared on various aspects of the project. A list of titles of reports completed in the series is annexed.

Inquiries concerning the subject matter of any particular report should be directed to the author,

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.

This electronic document has been scanned using optical character recognition (OCR) software. FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

CONTENTS

ABSTRACT

1. INTRODUCTION

2. METHODS

3. RESULTS

4. DISCUSSION

5. REFERENCES

APPENDIX

FEEDS FOR CATFISH (Clarias batrachus Linn.) FRY¹

Samran Dhamrongrat² and Prasit Kasesunchi³

ABSTRACT

Bioled rice bran, Moina sp., boiled tilapia flesh, fresh chub mackerel viscera and fresh pig blood were tested as feeds for raising fry of pla duk dan (Clarias batrachus). The fry, averaging 0.233 to 0.316 g, were reared in pottery water jars containing 5 l of water that was exchanged every two days. The feeds were applied at the rate of 5% of the body weight of the fry/day.

At the end of the 65 day trials the best growth gains, ranging from 0.51 to 0.82 grams/fish, were attained with the Moina, tilapia and mackerel feeds. Average weight gains with the rice bran and pig blood feeds were 0.35 and 0.38 grams/fish, respectively. Survival was relatively high in all cases, ranging from 71 to 92%. The highest net production in each trial was with mackerel feed, being the equivalent of 10.6 kg/m³ in trial No.1 and 6.5 kg/m³ in trial No.2; the corresponding values for tilapia feed were 8.1 and 6.0 kg/m³ while net production on Moina feed in trial No.1 only was 9.9 kg/m³.

Reasons to account for differences in growth and production results for the same treatment, between trials, were not evident.

¹ This working paper is a translated version of a report which appears in the Thai Fisheries Gazette, 18:219–313 (1965) under the transliterated title “Food experiments on juvenile catfish (Clarias batrachus Linn.)”. A first draft in English was prepared by Vijai Srisuwantach, fisheries biologist, National Inland Fisheries Institute, Bangkhen, Bangkok. The version presented here was developed by Dr. Alex Fedoruk, Senior Fisheries Biologist with DOF-UNDP/FAO Project THA/75/012 in Thailand, from the draft and discussion with Vijai Srisuwantach. Transferring information by this means is subject to the limitations inherent in relaying from one language to another. Shortfalls in the information presented may thus be a reflection of communication rather than of source.

² Formerly, Head of Bangkhen Fisheries Station, Bangkok, Thailand. Presently, Director, Conservation and Extension Division, Department of Fisheries, Bangkok, Thailand.

³ Formerly, fisheries biologist, Bangkhen Fisheries Station, Bangkok, Thailand.

1. INTRODUCTION

Fry for pla duk (= Clarias) farming in Thailand are initially obtained by capturing them in swamps, rice fields and flooded low lands. They then must be reared under special conditions until they reach a size suitable for stocking in ponds. A particular concern in this rearing phase centers on providing the fry with diets that will promote suitable growth and that can be obtained from readily available feeds.

Observations on wild fish by Vanichkorn (1957) indicated that Clarias fry feed on Moina sp., along with other materials of animal origin. Sidthimunka and Aguru (1959) reported that Clarias is omnivorous. Bannasopist (1959) reared pla duk fry in concrete tanks and found that the fish grew better when fed on minced tilapia flesh rather than on boiled egg yolk or rice bran. Lersprasert (1960) reared Clarias fry in small cages feeding them fresh chub mackerel viscera and Moina; they increased in size from 1.5 to 2.0 cm to 3.5 to 5.5 cm in 14 days. Both Nitjin (1956) and Vorawan (1957) conducted proximate analyses of some of these feeds reporting the results as follows:

The study herein was undertaken as a means to determine suitable feeds for Clarias fry as might be revealed in controlled feeding trials comparing five likely kinds of feed - boiled rice bran, Moina sp., boiled tilapia flesh, fresh chub mackerel viscera and fresh pig blood.

2. METHODS

The studies were conducted at the Bangkhen Fisheries Station. Cylindrical, unglazed pottery water jars were used as rearing vessels. They measured 19 cm in diameter and 34.5 cm in height and were provided with 20 cm of water giving a rearing volume of 5 1 which was exchanged every 2 days. The water, consistently with a pH of 7, was obtained from a well. Ipomea aquatica leaves were place in each jar to provide a hiding substrate for the fry.

Feeds were tested in two sets of trials, No.1 and No.2. The first ran for 65 days in the period September 12, 1961 to November 15, 1961. Each of 16 jars was stocked with 25 g of C. batrachus fry (averaging 0.28 g in weight and 3.6 cm in total length). Four feeds, boiled rice bran, Moina, boiled tilapia flesh and fresh chub mackerel viscera in each of four jars. The second set of trials, also over 65 days, took place from March 2, 1962 to May 5, 1962. This time three feeds, boiled tilapia flesh, fresh chub mackerel viscera and fresh pig blood were compared in 4 replications of each in 12 jars initially stocked with 20 g of C. batrachus (averaging 0.26 g and 3.0 cm) per jar.

The amount of feed given was 5% of the body weight of the fish per day. Actual numbers and size of fish present was determined on days 10, 25, 45, and 65 when feeding quantities were correspondingly adjusted. All fish were counted at these times while lengths and weights were measured on samples of 25 fry which were then returned to their respective jars.

3. RESULTS

The differences in results amongst replications of a treatment were invariably small. Consequently, all values for a treatment were determined by combining the results of replications and averaging them. Data tables are presented in the Appendix to this report.

Growth curves of the fry fed on the various feeds are illustrated in Figure 1 whereas Table1 summarizes the overall result of the trials in the presentation of growth and production parameters by treatment. This information indicates that the fry grew best when fed on tilapia mackerel and Moina feeds. In trial No.1 the average net gain attained by individual surviving fry over the 65 day rearing time was 0.823, 0.713 and 0.617 grams. Fry fed on rice bran only achieved a weight gain of 0.357 grams. The growth of fry in trial No.2 was less than in trial No.1 for equivalent treatments; the best weight gains, however, were attained with the tilapia (0.520 g) and mackerel (0.513 g) feeds as opposed to pig blood where the increment was 0.388 grams.

Survival rates were relatively high in all cases ranging from 71 to 92% (Table 1).

Of the 7 treatments productivity was highest with Moina feeds where on day 65 the mass of fish per jar was 72.7 grams (Table A-5) which equates to 14.5 kg/m³. The next highest was attained with mackerel feed being 65.5 grams (14.2 kg/m³) in trial No.1 and 50 grams (9.9 kg/m³) in trial No.2. The lowest values were with rice bran (42.5 g = 8.5 kg/m³) and pig blood (43.5 g = 8.6 kg/m³).

4. DISCUSSION

Boiled tilapia flesh, Moina and fresh chub mackerel viscera appear to be suitable feeds for nursing C. batrachus fry. Comparatively better growth was attained with the use of these feeds than with boiled rice bran and fresh pig blood that were also tested in the experiments.

Figure 1. Growth curves of C. batrachus fry fed on various test feeds in two trials, 1961 and 1962, Thailand.

Table 1. Growth and production parameters of C. batrachus fry reared over 65 days in trials comparing various feeds, Thailand 1961 and 1962.

The particularly high survival rates of the fry in the trials may indicate that the rearing methods were quite satisfactory. Changing water every two days could have been a singularly important factor.

Reasons to account for the differences in growth of fry fed on tilapia and mackerel between trials No.1 and No.2 are not clear. They may relate to feed quantities which were not generally determined with a precision that would preclude a large variation, or to environmental factors such as differences in temperatures through each trial. Alternately the growth differences may merely be expressions in a normal range of results that could be expected from the experimental practices employed.

5. REFERENCES

Bannasopist, T., 1959.
Experiments on catfish (Clarias batrachus) culture. B.Sc. Thesis, Univ. Kasetsart, Bangkok, Thailand: 42 p (in Thai).

Lersprasert, N., 1960.
Clarias culture in floating basket. Thai Fisheries Gazette 13: 303–306 (in Thai).

Nitjin, P., 1956.
Analysis on food nutrition of some freshwater fishes. B.Sc. Thesis, Univ. Kasetsart, Bangkok, Thailand: 40 p (in Thai).

Sidthimunka, A. and P. Aguru, 1959.
Report on the yield of Clarias breeding by natural method. Thai Fisheries Gazette. 12: 253–259. (in Thai).

Vanichkorn, P., 1957.
How to culture the Clarias. Thai Fisheries Gazette. 10:39–49. (in Thai).

Vorawan, C., 1957.
Animal food ingredients. In “A handbook on the principles of animal feeding”, Kasetsart University, Bangkok, Thailand. (in Thai).

APPENDIX

Data Tables

Table A-1. Growth of C. batrachus fry in trial No.1, September 12 to November 15, 1961. (replications averaged).

Table A-2. Growth of C. batrachus fry in trial No. 2, March 2 to May 5, 1962. (replications averaged).

Table A-3. Total number of fish and survival rate through trial No.1, September 12 to November 15, 1961 by treatment (replications combined) where “No.” = number of fish and “S.R.” = survival rate(%).

Table A-4. Total number of fish and survival rate through trial No.2, March 2 to May 5, 1962, by treatment (replications combined) where “No.” = number of fish and “S.R.” = survival rate (%).

Table A-5. Biomass of C. batrachus fry through trial No.1, September 12 to November 15, 1961, in gram total weight of fish in a single rearing jar (replications averaged).

Table A-6. Biomass of C. batrachus fry through trial, No. 2, March 2 to May 5, 1962, in grams total weight of fish in a single rearing jar (replications averaged).

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