THA/75/012/WP 12 ASSESSMENT OF A VITAMIN AND MINERAL PREMIX IN AN ARTIFICIAL FEED FOR PLA DUK OUI (Clarias macrocephalus) FRY CONTENTS

by

Krittiya Taechajanta and Prasert Sitasit

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 AND DISCUSSION

Tables:

1. Composition of test diets for feeding C. macrocephalus fry

2. Composition of mineral premix used in preparing fish feeds (NIFI formulation 102)

3. Composition of vitamin premix, NIFI formulation 101, used in preparing fish feed

4. Total daily ration fed to each lot of fish in the trials

5. Growth and production parameters of C. macrocephalus fry reared over 32 days in a trial comparing two artificial diets

ASSESSMENT OF A VITAMIN AND MINERAL PREMIX IN AN ARTIFICIAL FEED FOR PLA DUK OUI (Clarias macrocephalus) FRY¹

Krittiya Taechajanta² and Prasert Sitasit³

ABSTRACT

Clarias macrocephalus fry were reared on two artificial feeds, one with a vitamin and mineral premix and the other without. The fry, 15 day old fish averaging 0.2 grams each, were stocked at the density of 1,000/m² in fibre glass tanks and were fed at the presumed rate of 5% of their body weight/day.

At termination of the trials (33 days) survival in lots fed on food with the premix was 79% and the average size of the fish was 0.65 g. Survival in the opposing treatment was 35.18% and the average size of the fish was 0.48 g.

Cost estimates indicated that the diet with the premix could be prepared for about 10฿ (US$0.50)/kg and that 1฿ (US$0.05) worth of feed would be required to feed 100 fry for 30 days.

¹ Completed as a component study under the DOF-UNDP/FAO “Programme for the Development of Pond Management Techniques and Disease Control (THA/ 75/012)”. Initially reported in Thai as a contribution of the Fish Nutrition and Disease Division to the 1980 Annual Report of the National Inland Fisheries Institute, Bangkok, under the transliterated title “A Study on Rearing Clarias macrocephalus Fry with Artificial Feed”. The version presented here was developed by Dr. Alex Fedoruk, Senior Fisheries Biologist with DOF-UNDP/FAO Project THA/75/012 in Thailand, from a draft in English prepared by, and discussion with, Prasert Sitasit. 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 Fisheries biologist, National Inland Fisheries Institute, Bangkok.

³ Chief, Fish Nutrition Unit, National Inland Fisheries Institute, Bangkok.

1. INTRODUCTION

Common feeds for rearing Clarias macrocephalus fry in Thailand are boiled egg yolk, Moina sp., and ground trash fish. Problems, however, occur with these feeds. Water quality becomes degraded, sometimes severely, when boiled egg yolk and trash fish are used. Furthermore, trash fish is suspected of being an inappropriate food because of its likely content of antithiamine compounds which prevent normal digestion. Although fry grow satisfactorily when fed on Moina sp., availability of the feed is limited and the price is excessive.

Advances in fish nutrition technology generally indicate that water degradation problems can be prevented by using artificial feeds. Preparing them at an acceptible cost for use in Thailand, however, remains to be determined particularly if ingredients have to be imported.

A variety of relatively low cost, locally available materials are suitable for constituting basic diets for C. macrocephalus fry. The need to include vitamin and mineral premixes, usually provided as a commercially prepared package, in these diets is, however, untested.

The study herein was undertaken to assess the inclusion of a vitamin and mineral premix in a basic artificial diet constituted with locally available ingredients as a food for C. macrocephalus fry.

2. METHODS

The study was conducted at the National Inland Fisheries Institute, Bangkok, during the period August and September 1979.

Two diets, constituted as shown in Table 1, were prepared. Proximate analysis, about the same for each diet, was:

Table 1. Composition of test diets for C. macrocephalus fry.

The mineral and vitamin premix was prepared by first constituting the mineral component (Table 2) and the vitamin component (Table 3). These were blended individually then combined in a proportion by weight 11:2 for the mineral and vitamin components, respectively. The resulting mixture was stored at room temperature in sealed plastic bags.

Table 2. Composition of mineral premix used in preparing fish feeds (NIFI formulation 102).

Table 3. Composition of vitamin premix, NIFI formulation 101, used in preparing fish feed (amounts shown are those used to make a 2 kg batch).

The ingredients were combined by blending them in a horizontal mixer for 20 to 25 minutes. The resulting powder was placed in plastic bags, sealed, and stored at room temperature. Feed was delivered to the fish as “dough” made by mixing water (30% by weight) with the powder.

The test diets were fed to C. macrocephalus fry held in four fibre glass tanks with a surface area of 1.472 m² each and containing 25 cm of water. All fry were obtained from a supply developed at the National Inland Fisheries Institute in induced spawning experiments. At the start of the feeding trials they were 15 days old and averaged 1.8 cm in length and 0.182 g in weight. The fry were first treated in a formalin bath (20 ppm) for 24 hours then stocked in the rearing tanks at the density of 1,000/m² or 4,000/m³.

During the trial period of 33 days about 4/5 of the water in each tank was exchanged every 3 days.

Two lots of fish were fed with “diet No.1” and two with “Diet No. 2”. The fish were fed twice a day. The total amount of feed given per day was predetermined as shown in Table 4 on the basis of expected growth and this amount was delivered regardless of apparent mortalities.

Table 4. Total daily ration fed to each lot of fish in the trials.

3. RESULTS AND DISCUSSION

Differences in results between replications were very small so values reported in this report are the average of replications. Table 5 summarizes the performance of the fish in response to each treatment.

The results are conclusive in showing that a vitamin and mineral premix is definitely required as an ingredient in basic artificial feeds constituted from local materials. Weight gains (0.468g/fish) and survival rate (76%) was about double in the treatment with the vitamin and mineral premix as opposed to the treatments without the premix where gains were 0.298g/fish and survival was 35%.

Estimates on costs indicate the practical feasibility of using artificial diets for rearing Clarias fry. Production costs to prepare the diet with the premix was about 10 Baht (US$0.50) per kg. The amount of this food delivered per 100 fish was valued at 1 Baht (US$0.05). The materials cost of the premix ingredient accounted for about 14% of the above. In comparison, the material cost of a nutritionally equivalent amount of trash fish to 1 kg of artificial food is about 9 Baht (US$0.45), however, such food likely lacks the full compliment of vitamins and minerals.

Table 5. Growth and production parameters of C. macrocephalus fry reared over 32 days in a trial comparing two artificial diets.

The Programme for the Development of Pond Management
Techniques and Disease Control
(DoF-UNDP/FAO THA/75/012)

Reports