Use of Cottonseed Meal in Aquatic Animal Diets: A Review

Abstract

Cottonseed meal is a plant protein source that is abundant in most parts of the world, relatively high in protein, and generally less expensive per unit of protein than soybean meal. It is highly palatable and readily digested by most aquatic animals, though generally not as digestible as soybean meal. Its use in aquaculture feeds may be limited because of the potential toxic effects of free gossypol and its relatively low available lysine and methionine content. However, depending on economics, the protein quality of cottonseed meal can be improved by supplementing it with lysine or both lysine and methionine. Also, the concentrations of free gossypol in diets containing significant levels of cottonseed meal are typically below the levels that are detrimental to many aquatic animals. However, even as a partial replacement of soybean meal, cottonseed meal has generally been used at relatively low levels in aquatic animal diets, partially because the safe levels of cottonseed meal appear to differ for various fish and crustaceans. Although some cultured aquatic species can tolerate relatively high dietary levels of cottonseed meal, its use will probably continue to be limited to about 10–15% of their diets. Although this is largely related to the higher nutritive value of soybean meal, it is, to a lesser degree, because of the variation of free gossypol levels in various sources of the meal and the potential toxic effects of gossypol on certain aquatic animals. However, when market conditions are favorable, the use of cottonseed meal will increase because some aquatic animals are largely unaffected by free gossypol, and for them cottonseed meal can lower rearing costs.