Karanj protein isolate prepared from karanj seed cake: Effect on growth, body composition and physio-metabolic responses in Labeo rohita fingerlings.

Abstract

A protein isolate was prepared from karanj seed (KPI) with 921.2 g protein/kg seed, which contained a negligible amount of anti-nutritional factors and a balanced amino acid composition, especially rich in methionine. For 60-day feeding trial, five isoni-trogenous (300 g/kg CP) and isocaloric (15 MJ DE/kg) diets were formulated by re-placing soybean protein isolate (SPI) on protein equivalent basis, KPI-0 (control, 0 g/kg KPI); KPI-25 (replacing 250 g/kg SPI protein with KPI); KPI-50 (replacing 500 g/kg SPI protein with KPI); KPI-75 (replacing 750 g/kg SPI protein with KPI) and KPI-100 (replacing 1,000 g/kg SPI protein with KPI) for the feeding of L. rohita. The weight gain percentage, specific growth rate, feed conversion ratio and protein efficiency ratio were not significantly (p > .05) varied among the KPI fed and control groups. A significantly higher hepatosomatic index was recorded in the control and KPI-25 groups compared with other groups. The whole-body compositions, except ether ex-tract, did not differ significantly (p > .05) among the groups. Digestive (amylase, pro-tease, lipase and alkaline phosphatase) and metabolic enzyme activities (hexokinase, transaminases and lactate dehydrogenase) and glycogen stores were not significantly affected, whereas intestinal alkaline phosphatase differed significantly (p < .05). The RNA–DNA ratio was significantly (p < .05) higher in the KPI-75 group. Thus, the study revealed that KPI can completely replace SPI protein at 191 g/kg inclusion level in the diets of L. rohita fingerlings.