Use of wild fish and other aquatic organisms as feed in aquaculture in the Asia-Pacific 77
and Babylon snail (Babylonia areolata), providing all the nutritional requirements of
the cultured stock. These cultured species are all relatively high-valued and are cultured
primarily for export and the local, up-market, restaurant trade. The culture practices
used for these commodities would normally fall within the realm of intensive culture,
and it is thus an exception to the rule that these stocks obtain their nutrition from a
single ingredient.
The other main category of feeds used in aquaculture is formulated feeds.
Formulated feeds can be divided into two basic types, viz. “farm-made” or “home-
made” feeds and commercial feeds. For the former, the formulations are based on
locally available ingredients and, in general, are not strictly in accordance with the
nutrient requirements of the cultured stock(s). These feeds, as the name implies, are
made on farm (in accordance to the specifications provided by the farmers) or by small
enterprises that are locally based and cater to a restricted farming community(ies). These
feeds are made in small quantities, at most a week’s supply at a time, based on needs
and demand. Bearing in mind that the great bulk of Asian aquaculture, in particular
inland finfish culture, is semi-intensive, these feed types are an important entity in the
chain of events, and will undoubtedly impact on the long-term sustainability of Asian
aquaculture.
BOX 2
Catfish farming in Thailand
Hybrid catfish (Clarias macrocephalus x C. gariepinnus), the most important freshwater fish cultured
in Thailand, accounted for a production of 189 940 and 130 784 tonnes in 2004 and 2005, respectively.
However, over the last few years the farmgate price of catfish has declined, which is also reflected in
the decreased total production. In an effort to be more cost effective, catfish farmers have adopted
new strategies, the foremost of which is a change of ingredients used in farm-made feed, whereby
they have shifted from the use of trash fish to wastes from the poultry processing industry. The farm-
made feeds use 8 parts of poultry waste (skeletal frames with bits of flesh), 1.5 parts of lard from the
cattle slaughter industry and 0.5 parts of salt. The feeds are readily accepted by the stock, and the
farmers believe that the production returns have not changed. The cost of feed has been reduced by
approximately 30 percent. Of course the nutritional basis behind this change remains unexplained,
a situation comparable with that previously described by Wood et al. (1992) for shrimp farming
in Andhra Pradesh, India, where the traditional farm-made feeds performed far better than feeds
formulated on the strict nutritional requirements of the cultured stock. This change among catfish
farmers in Thailand has resulted in a significant reduction in the dependence of freshwater finfish
culture on trash fish, with apparently no change in consumer acceptability of the product.Photos: Feed preparation, feeding of cultured fish and voraciously feeding catfish