Effects of replacing fish meal with plant proteins at different dietary protein levels on growth and feed intake regulation of juvenile channel catfish Ictalurus punctatus

Abstract

This study aimed to evaluate the effects of partial and total replacement fish meal with plant proteins at different dietary protein levels on growth and feed intake regulation of juvenile channel catfish Ictalurus punctatus. 1800 fish were distributed into 36 cement pools at a density of 50 fish in four replicates and were fed with nine practical diets with three fishmeal (FM) level (0, 30 and 60 g/kg) and protein (P) levels (300, 330, 360 g/kg), and they were designated as F0P300, F30P300, F60P300, F0P330, F30P330, F60P330, F0P360, F30P360, F60P360 at 30, 60 and 90 days according to a 2-way design. From the result, specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), Somatostatins (SST) and cholecystokinin (CCK) were not affected by either FM or protein levels, in 30 and 60 days. Feed intake (FI), insulin-like growth factor (IGF-1), growth hormones (GH) and Neuropeptide (NPY) were significantly affected only by dietary protein levels in fish fed 300 and 330 g/kg at 30 days. At 60 days, GH, IGF-1, SST, CCK significantly upregulated in fish fed 330 and 360 g/kg protein in term of dietary protein level, while no difference was observed in FM levels. Furthermore, NPY upregulated in fish fed 330 g/kg protein and 60 g/kg FM level. At 90 days, GH increased in fish fed 60 g/kg FM level, but no difference was observed in protein level. SGR and FI were significantly increased in fish fed 330 g/kg. FCR, PER, SST, IGF-1, CCK and NPY were affected by both FM and protein levels. In conclusion, the study indicated that the optimum protein level for channel catfish is 330 g/kg with 60 g/kg FM, and there was no growth retardation by increasing dietary protein level to 360 g/kg with or without fishmeal.