Fungus, Aspergillus niger, fermented groundnut oil cake as a fishmeal alternative in the diet of Penaeus vannamei

Commercial de-fatted groundnut oil cake (GNC) fermented with the fungus Aspergillus niger was evaluated as a fishmeal alternative in the diet of Penaeus vannamei. A 45-day growth trail was performed using nine iso-nitrogenous and iso-lipidic diets. Untreated/fermented GNC was included at the rate of 0 (control), 25, 50, 75 and 100g/kg by replacing fishmeal (w/w). Each diet was randomly assigned to triplicate group of 20 shrimps (initial weight of 3.09 +/- 0.03g). Results revealed that shrimp fed with diets having untreated GNC up to 50g/kg has no significant difference in growth, whereas the inclusion level was enhanced to 100g/kg with fermented GNC with no deleterious effect. The negative linear trend was found for SGR with increasing the inclusion of both untreated and fermented GNC. The feed and protein efficiency measures, viz. feed conversion ratio, protein efficiency ratio and apparent protein utilization, were better in shrimps fed with diets having fermented GNC than those fed the respective level of untreated GNC. The broken-line analysis indicated that the inclusion of 72.5g/kg fermented GNC showed the best FCR. No significant difference was observed in survival (86.67%-96.67%) between the dietary treatments. There was a significant difference in ether extract of shrimp between the treatments, whereas other parameters were not affected. Haemolymph indices showed a significant difference in total protein, glucose, cholesterol and triglycerides between control and test diets. The results conclude fermented GNC, which can be better than untreated one in the diet of shrimp.