The Potential Use of Salted Marine By-Catches and Fish Viscera Meal Mixture as A Replacement for Conventional Fishmeal in the Diet of Indonesian River Catfish (Hemibagrus nemurus)

Abstract

Abstract The research was conducted to investigate the substitution effect of dietary salted marine by-catches and fish viscera meal mixtures for conventional fishmeal on physicochemical and sensory quality of Indonesian river catfish. Four experimental diets containing 34% crude protein and 3.20 kcal g−1 digestible energy were formulated. A control diet (FM) contains 54% fishmeal and no salted marine bycatch - fish viscera mixture (SMBFVM). In the other diets, the fishmeal was reduced and proportionally replaced with SMBFVM, 50% (SMBFVM-50), 75% (SMBFVM-75) and 100% (SMBFVM-100). A commercial diet (CD) containing 32 % crude protein and 2,94 kcal g−1 digestible energy was used as the reference. Feeding trial was performed with 1500 fish (4.79±0.38 g in weight) which was distributed in 2x2x1.5 m triplicate net cages, and the fish was fed the experimental diets at satiation twice daily at 07:00 AM and 05:00 PM for 8 weeks. There was no substitution effect of fishmeal by SMBFVM on the survival rate of the fish (P>0.05). Substitution of fishmeal by SMBFVM in the diet up to 75% (SMBFVM-75) increased weight gain, specific growth rate, food efficiency ratio, protein efficiency ratio and protein retention (p<0,05) better than control diet; and complete substitution of fishmeal with SMBFVM (SMBFVM-100) gave similar growth performance to control diet (P>0.05). Total replacement of fishmeal with SMBFVM in the diets also gave comparable body fish proximate and amino acid profile to control diet. Compared to CD, fish fed SMBFVM diets had similar growth performance, body proximate, and amino acid profile. The SMBFVM, therefore, could completely replace conventional fishmeal in the diet for Indonesian river catfish without negative effects on fish growth, body proximate, and amino acid profile.