Oxidative damage in tissues of juvenile crayfish (Cherax quadricarinatus von Martens, 1868) fed with different levels of proteins and lipid

This experiment investigated the effect of dietary protein and lipid levels on superoxide radical production and lipid peroxidation in juvenile redclaw crayfish, Cherax quadricarinatus. Nine practical diets were formulated to contain a combination of three crude protein (CP) (26, 31, and 36%) and three crude lipid (CL) (4, 8, and 12%) levels. Four replicate groups of 15 crayfish (0.71 +/- 0.13 g) per diet treatment were stocked in 40 L tanks, at 28 degrees C for 60 days. The control group was fed with a commercial shrimp diet. After the feeding period, superoxide radical (021 production and lipid peroxidation, measured as thiobarbituric acid reactive substances (TBARS) of muscle, digestive gland and gill were analyzed. In the group fed the control diet, O-2(-) production and TBARS levels were significantly higher in the digestive gland than in muscles or gills. There was no effect of dietary protein or lipid level on O-2(-) production in the digestive gland, muscle, and gill. However, dietary protein level significantly affected TBARS levels in crayfish gills (p < 0.05). The results suggest tissue-specific effects of dietary protein and lipid levels on indicators of oxidative stress in redclaw. Results indicate that a diet containing 31% CP and 8% CL provided adequate amounts of protein and lipid to satisfy nutritional requirements for optimal growth, while preventing diet-induced oxidative stress and protecting the integrity of the immune function.