The National Inland Fisheries Institute has the potential to contribute towards more precise knowledge on the nutritional requirements of species indigenous to Thailand. This knowledge is much needed for development of the country's aquaculture industry in general, and for more effective exploitation of its abundant feed resources in particular.
The Institute's physical facilities, after the recommended improvements, will be adequate to support a research programme in fish nutrition that emphasizes the more practical aspects of aquaculture. This includes development of practical diets, based on locally available ingredients that are efficient as well as economical to use, and investigations into nutritional disease problems that appear to be associated with traditional feeding practices, both as a service to the industry and as a means for understanding the nutritional requirements of the cultured species.
Feed mill
Modifications to the material flow system of the mill should be carried out according to plans described earlier in the report. To permit efficient operation of the mill, a larger steam boiler and a hammer mill of 20 to 30 HP should also be provided. Two alternative plans were proposed for the modifications, one by the author and the other by a prospective donor. The one proposed by the author has been based on extensive experience in mill operation and design. The mill, modified according to these plans, will eventually require the services of a skilled operator. However, in the long term, the mill can be more efficiently operated with considerable savings in labour and equipment maintenance expenses. The Institute should pursue this matter with the prospective donor for acceptance of the better alternative.
Nutrition laboratory
Although the analytical capability of the nutrition laboratory is at present limited to proximate analysis of feeds and vitamin assay, requirements for research in diet development is not expected to expected to exceed the present routine. Nevertheless, some upgrading of equipment will be necessary, especially with regard to the replacement of old equipment by new ones having higher sample throughput.
Practical diet development
Development of practical diets should be given priority over basic studies on nutrient requirements of the species. Skills should be acquired by the nutrition staff to set up mattrices and constraints for computerized least-cost formulation of test diets based on a full range of ingredients available in the country. The arrival of the HP-3000 mini-computer system purchased for the lead centre will make this possible.
Binary diets
As pointed out earlier, the Thai catfish farmers' feeding practices continue to be very much influenced by tradition. The tradition of using trash fish and rice bran probably developed during the period when the list of readily available feed ingredients was still quite limited because of lack of demand by a yet undeveloped feed industry. The quantity of trash fish reduced to fish meal annually 15 years ago, for example, was very small and trash fish was then quite cheap and plentiful. Rice bran, on the other hand, has always been readily available, as it still is today, in those parts of the country where fish farming activity is concentrated. The result was the development of moist, binary-type feed that was easy to prepare and inexpensive to use.
The success of a commercial replacement for traditional farm-prepared feeds will be determined not only by the new product's ability to support rapid growth with high percentage fish survival at market time, but also by its cost-effectiveness. Manufacturing and marketing costs of compound feeds have risen dramatically over the past decade as a result of a tenfold increase in energy cost. Production cost of dry pelleted feeds is particularly high. Apart from cost factors, the farmers' prejudice against new diets (in this case, of feeding dry pelleted feed opposed to their traditional moist feed) has to be overcome. In the author's opinion, based on personal experience with catfish farmers in Thailand in the past, such prejudices are deep rooted.
In order to reduce the cost of manufactured feed usage and to make as little change in feeding methods as possible, another binary type feed should be developed, in which one of the binary components is a mixture of ingredients that is readily available in the vicinity of the farm (e.g., rice barn) and the other component, a feed concentrate which, when mixed with the other component of the binary, will provide a well balanced diet for full feeding of fish. Instructions will have to be provided on the proportions the binary components should be mixed for a specific feeding purpose. The mixture can then be made into a moist pelleted feed, which the fish farmer is most accustomed to use on the farm site. Significant savings arise from lower transportation expenses. Other savings will be from cheaper processing costs at the farm, the amount depending upon processing methods used and energy source available.
Test diets specified in Tables 3, 4 and 5 may be fashioned as binary diets, with rice barn in each diet constituting the component supplied at the farm and a mixture of all the other ingredients, the other component, supplied by the feed manufacturer.
