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Like other crustaceans, narrow-clawed crayfish (Astacus leptodacylus Eschscholtz, 1823) can change its diet to the available food during varied life cycles. Diet alteration can affect different biological indices of this species, therefore this study aims at studying changes in growth indices, hemolymph biochemical parameters and biochemical quality of its carcasses, which might occur during diet change of crayfish. The purpose of this experiment was to evaluate the effects of partial replacement of fish meal with soybean meal on growth performance, carcass quality and hemolymph biochemical parameters of narrow-clawed crayfish. 90 healthy adult narrow-clawed crayfish (W=35.50±4.05 g; TL=16.96±1.92 cm) were randomly distributed into 9 fiberglass tanks (200 L) and were fed for 45 days with three varied diets including: commercial shrimp diet, fishmeal-based diet (A) and soybean meal-based diet (B). The results show that changing the diet from animal protein to plant protein caused a significant decrease in the cholesterol and triglyceride levels in hemolymph, as well as carcass fat of the crayfish nourished with B diet when compared with the crayfish fed with A diet. No significant changes of hemolymph levels of glucose, AST and ALT were found between different treatments during this experimental period. In conclusion, it was found that though growth performance reduced, the increased rate of soybean meal in diet from 0.0% to 76% had no adverse effects on biochemical parameters.

The effects of four protein sources (soybean meal, sunflower meal, pea and fish meal as the main protein source) were investigated on fattening performance, carcass and meat quality traits and body composition of pigs. Eight animals per treatment received the diets from 30 to 105 kg live weight at a level of 3.0 times maintenance requirement of energy. Diets were formulated on the basis of ileal digestible protein and amino acid content of feedstuffs. Protein sources resulted similar fattening performance from 30-105 kg body weight. From 30 to 60 kg soybean treatment had lowest performance. The protein source treatments did not alter the body composition, lean meat percentage, liver weight and meat quality (intramuscular fat content, pH 45 min and 24 hours after slaughter, drip loss, meat lightness and hue measured 24 hours and 4 days after slaughter). It can be concluded that protein sources can be replaced without affecting overall fattening performance, carcass and meat quality and body composition if diet formulation is based on the ileal digestible amino acid contents of feedstuffs. However the lower performance of the soybean treatment in the first phase may indicate that ileal digestible Lys content of heat treated protein sources may not characterise the feedstuffs well enough. It may be that young pigs are more sensitive to unavailable lysine by the way.