Silk cotton cake as an alternate protein source in the diet of tiger shrimp, Penaeus monodon Fabricius 1798, and its effects on growth, nitrogen utilisation and metabolism

Abstract

Silk cotton cake (SCC) was incorporated in the practical diets of tiger shrimp, Penaeus monodon at 5 different levels (0, 2.5, 5.0, 7.5 and 10.0%) by replacing fish meal. Growth cum digestibility study was conducted for 45 d in 500 l experimental tanks using shrimps weighing 2.09 ± 0.06 g with three replications for each treatment. There was significant (p<0.05) reduction in specific growth rate (SGR) and daily growth coefficient (DGC) in shrimps fed diets having more than 2.5% SCC compared to other treatments. Apparent crude protein, lysine and methionine digestibilities decreased (p<0.05) in shrimp fed with more than 2.5% SCC incorporation. The free amino acid profiles of shrimp muscle at 4 h post-feeding indicated significantly (p<0.05) lower levels for lysine and methionine in shrimp fed with higher levels of SCC. Post-prandial ammonia nitrogen excretion (PPANE) on hourly basis revealed that incorporation of SCC has greatly influenced the N excretion. SCC incorporation has not affected the haemolymph protein concentration up to 7.5% and the haemocyanin content up to 5% inclusion. The experimental results indicate that SCC can be incorporated up to 2.5% in the diet of black tiger shrimp P. monodon