The effects of dietary astaxanthin on some stress factors, survival rate and growth performance of white shrimp (Litopenaeus vannamei) juveniles at different stocking densities

Current research carried out to identify the effects of dietary astaxanthin on some stress factors, survival rate and growth performance of White Shrimp (Litopenaeus vannamei) juveniles reared on different stocking densities. Experimental design was planned for different stock densities (200, 400 and 800 indv./m3) and individuals were feed with extrude shrimp feed with different rates of astaxanthin supplement (0, 40, 80 and 150 mg/kg). Experiments were conducted for 56 days. Evaluation of our results indicated that the highest survival rate (%81,67±9,28) was achieved for the less dens experiment group with no astaxanthin supplement (group A1B1) while highest mean weight (1,81±0,21 g) was achieved for most dense experiment group feed with feed with 80 mg/kg astaxanthin supplement (A3B3). Recorded highest final stocking density rate (463,30±32,83 indv./m3) was also achieved for experiment group A3B3. It was observed that, for densely populated experiment groups (A3), stress associated with the stock density repressed by the non-enzymatic antioxidant defence system. Also the diets with 40 and 80 mg/kg astaxanthin found to have a regulating effect on antioxidant defence system. Our study has highlighted that the survival rate of shrimps was effected both by stocking density and astaxanthin rates in diet (p<0.05). Stocking density found to have a significant effect on all observed growth rates of juvenile (p<0.05) while the effect of astaxanthin didn't affect the growth rates significantly (p>0.05).