Dietary amino acid requirements of fingerling hybrid catfish (Clarias macrocephalus x C. gariepinus) as estimated by the ideal protein approach

Nguyen Duy Quynh Tram¹, Le Duc Ngoan¹, Jan Erik Lindberg²

¹Hue University of Agriculture and Forestry,

²Swedish University of Agricultural Sciences

Abstract

The requirement of essential amino acids (EAA) in hybrid catfish (Clarias macrocephalus x C. gariepinus) was estimated from the determined optimal dietary lysine requirement and the ideal EAA profile in catfish whole-body protein. Groups of 30 fish (4.0 ± 0.7 g) were stocked in triplicate in 130 L glass tanks and were fed semi-purified iso-nitrogenous diets (300 g kg^-1 crude protein (CP) and 18.3 MJ kg^-1 gross energy) with increasing levels of lysine (40, 45, 50, 55, 60 and 65 g kg^-1 CP). Weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and feed efficiency ratio (FER) were determined. Final weight, WG, SGR, PER and FER increased (P<0.05) with increasing dietary lysine level. There was no dietary effect on final carcass composition (P>0.05). Subjecting the data of WG, SGR to second-order polynomial analysis, the requirement of dietary lysine was estimated and was found to be in the range of 58.1 to 58.2 g kg^-1 of CP. Using whole-body protein EAA pattern, the dietary requirements of EAA were estimated and compared with the literature data.

Keywords: lysine, amino acids, requirements, hybrid catfish (Clarias macrocephalus x C. gariepinus), ideal protein