The presence of endogenous anti-nutritional factors within plant feedstuffs is believed to be the largest single factor limiting their use within compounded animal and fish feeds at high dietary levels. Figure 1 summarizes the major groups of anti-nutritional factors present in plant foodstuffs with more specific examples given in Table 3. Although these factors vary in their individual toxicity to fish, a large proportion of them can be destroyed or inactivated by heat treatment processes (Tacon and Jackson, 1985).
Unfortunately toxicological studies have not been performed on the majority of these anti-nutritional factors; on a general basis however their presence in untreated foodstuffs normally results in anorexia, reduced growth and poor food conversion efficiency when used at high dietary concentrations (for review see NRC, 1983).
