GROWTH AND SURVIVAL UNDER MONOSEX CULTIVATION OF JUVENILE REDCLAW CRAYFISH Cherax quadricarinatus IN RESPONSE TO SIX DIETS WITH DIFFERENT PROTEINS AND LIPID CONTENT

CORTÉS-JACINTO E, CESEÑA CA, GARCIA-GUERRERO M & LÓPEZ GRECO LS

Congreso; WAS 2011-NATAL-BRASIL; 2011

WORDL AQUACULTURE SOCIETY

The biology of the freshwater crayfish Cherax quadricarinatus is well known, with many studies about nutrition, mainly with protein requirements. This 70-day study evaluated the effect of six experimental diets (two levels of proteins and three levels of lipids) on growth and survival of males and females weighing about 10 g. The six diets were: 1 (18% protein, 4% lipids), 2 (18% protein, 8% lipids), 3 (18% protein, 12% lipids), 4 (24% protein, 4% lipids), 5 (24% protein, 8% lipids) and 6 (24% protein, 12% lipids). The parameters analyzed were: the SGR (Specific Growth Rate), SR (Survival Rate), PER (Protein Efficiency Ratio), FCR (Food Conversion Rate), and AMF (Apparent Molting Frequency). A proximate chemical analysis was made and a fatty acid and amino acids profile was assayed in test subjects and diets. In females, better growth was obtained with diet 6; in males, diets 4 and 5 gave better performance. Lower survival with 18% protein content occurred in males, but not in females (p < 0.05). Growth parameters were different among sexes (Table 1). SGR was higher at 24% protein, independent of the lipid level (p < 0.05) for females, but not for males. In males, SGR was higher at 24% protein at 4 and 8% lipids (p < 0.05). In females, FCR was higher at 24% protein/12% lipids, while there was no effect of the assayed diets on the FCR in males. PER did not depend on diet in females (p > 0.05), but lower protein levels increased PER in males (p < 0.05). AMF was lower in both genders at 24% protein and 12% lipids. The main results would indicate that the most suitable protein-lipid level for this species is 24% protein and 8% lipids; however, the differences between genders show that diet can be adjusted for each to optimize yields during the growing phase. The proximal analysis showed no differences between genders in the assayed diets and this seems to satisfy the requirements for cultivation of this species.