Influence of different dietary Astaxanthin levels on hemolymph biochemical parameters, total carotenoid content and intestinal microbial flora of the oriental river prawn, Macrobrachium nipponense

In the present experiment, two hundred and twenty-five oriental river prawns (Macrobrachium nipponense) with mean weight of 1.40±0.05 gram were fed by five formulated diets containing different astaxanthin levels, zero (control), 50, 100, 150 and 200 milligrams per kilogram in glass aquarium tank for eight weeks. At the end of the culture period, after collecting hemolymph and also the tissues of intestinal tract, muscle and exoskeleton were sampled, hemolymph biochemical parameters, total carotenoid content and intestinal microbial flora in prawns were studied. Hemolymph biochemical parameters such as urea, urea nitrogen, glucose, creatinine and triglycerides were decreased with increasing of astaxanthin levels, while HDL and LDL increased significantly (p<0.05). However, uric acid, calcium, phosphorus and cholesterol were not affected by astaxanthin treatments (p>0.05). Treatments containing 150 and 200 mg/kg astaxanthin showed the lowest total bacterial count. Intestinal lactic acid bacteria also increased in the treatment of 150 mg/kg astaxanthin (p<0.05). Total carotenoid content of prawns was elevated by increasing dietary astaxanthin levels (p<0.05). Generally, the results of present study showed that increasing dietary astaxanthin levels improves hemolymph biochemical parameters, total carotenoid content and intestinal microbial flora of the oriental river prawn and adding 150 milligrams astaxanthin per kilogram of this pigment to the diet was suggested to improve the parameters that mentioned of this prawn.