A comparative study on optimising the inclusion level of three different oilseed meals, cakes as a fishmeal substitute in the diet of Penaeus monodon Fabricius, 1798

Abstract

A 60-day indoor feeding trial was conducted in tanks to optimise the inclusion level of three oilseed meals/cakes, such as groundnut oil cake (GNC), rapeseed meal (RSM) and sesame oil cake (SOC), in the diet of Penaeus monodon Fabricius, 1798. Each test ingredient was included separately at the rate of 0 (control), 2.5, 5, 7.5 and 10% by substituting fishmeal (w/w). The shrimps were hand-fed the respective pellet feed thrice a day in a static condition at the rate of 8% of the total biomass and was adjusted based on the intake. Results revealed that RSM-fed groups showed a lower daily growth coefficient (DGC) (1.27% day-1) than the other two groups (1.29-1.30% day-1). The DGC decreased from 1.40 to 1.09% day-1 with increase in inclusion levels from 0 to 10%. Broken line regression indicated that the optimal inclusion level of GNC, SOC and RSM was 5.4, 2.9 and 2.4%, respectively. Digestibility of dry matter, crude protein, as well as of the amino acids, Arg and Met increased by 1.92, 0.72, 4.02 and 4.74%, respectively, at 2.5% inclusion, and the increase was extended up to 5% for His, Leu and Lys. The dietary change did not affect survival and carcass composition, while free amino acids in shrimp tail muscle varied among the treatments. Results concluded that all three oilseed meals/cakes are potentially viable and could substitute dietary fishmeal partially in P. monodon. In contrast, they were ranked as GNC > SOC > RSM according to the broken line model.