Growth and carcass quality of on-growing river catfish Hemibagrus nemurus fed with dietary salted by-catch and fish viscera meal mixtures as fishmeal substitute

Abstract

Dietary salted by-catches and fish viscera meal mixtures could totally replace fishmeal without negative effect on growth performance of small size (4–25 g) river catfish Hemibagrus nemurus, however, their effects on carcass quality and growth of on-growing river catfish remained uninvestigated. The present study therefore was conducted to assess the effects of dietary fishmeal (FM) replacement with salted by-catches and fish viscera meal mixtures (SBVM) on growth, feed utilization, and carcass quality of on-growing (120–300 g) river catfish. Four isoproteic and isocaloric (34% crude protein and 17 Kj g−1 gross energy) diets were prepared, where dietary FM was replaced with SBVM at levels of 0% as control diet (SBVM0), 50% (SBVM50), 75% (SBVM75), and 100% (SBVM100). A commercial pelleted diet (CD) was used as a reference. A total of 750 on-growing river catfish, 118.95 ± 2.19 g in weight was randomly distributed into 5 triplicate net cages (2 m × 2 m × 1.20 m) at a density of 50 fish per cage. The fish was fed at apparent satiation twice a day for a period of 90 days. Substitution of dietary FM with SBVM up to 75% did not affect survival rate, specific growth rate, weight gain, feed and protein efficiency, lipid retention, protein retention, amino acid profile, body proximate composition, edible flesh, carcass waste, dress-out percentage, flesh liquid holding capacity (P > 0.05). The sensory quality of the fish was comparable with the control and reference diets (P > 0.05). Complete substitution of dietary FM by SBVM negatively impacted specific growth rate, weight gain, feed intake, protein retention, body protein and lipid, lipid retention, flesh liquid holding capacity, and fillet appearance and texture (P < 0.05). Therefore, the SBVM can replace FM in the diet of river catfish up to 75%.