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Abstract
The experiment was conducted to compare the effect of partial substitution of fish meal (F) by two different protein sources, soybean protein concentrate (S) and poultry meal (P) in diets for juvenile groupers (E. coioides). The fish were fed test diets formulated from practical ingredients to contain 44% crude protein and 375〜385 Kcal/100g diet. Whole experiment were carried out in a circular system and duration ten weeks .
In the experiment 1, there are twelve test diets containing different levels of S and P as a replacement of white fish meal at four substitution levels: 25, 50, 75 and 100% of the fish meal protein(provide 36.5% dietary protein). Growth study indicated that the best percentage weight gain of groupers fed Diet 10(2F/1P/1S) was 302.40% and Diet 6 (3F/1S), Diet 2 (3F/1P) were 264.40%, 235.50%, which similar to that 297.33% of groupers fed all fish meal diet (4F). The weight gain of juvenile groupers decreased as the amount of P increased up to 50%, the relationship was described by the equation Y=19.11X+107.90 where Y is weight gain, X is fish meal protein levels which replaced by P. The percentage of fish meal protein replaced by S, that yielded maximum growth was 30.52%, based on a broken-line madel estimation of weight gain, these data suggest that P or S replaced fish meal protein 25% or both of them mixing together replacing fish meal 50% in test diets still keep similar growth for grouper.
In experiment 2, there were five test diets, 4F was described with 36.5% fish meal protein(4S), NAA was 4S diet without lysine/methionine and CAA, FAA, GAA, were 4S supplement with different type of lysine/methionine, crystalline, fat-coating and gelatin-coating. Supplement lysine/methionine in whole S diet (4S), has improve the growth, but different type of lysine/methionine (crystalline, fat-coating and gelatin-coating) used in the diets was not stastistically significant (p>0.05).
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