The use of linseed oil cake in the diets of rohu, Labeo rohita (Hamilton), after solid-state fermentation with a fish gut bacterium, Bacillus pumilus (KF640221): an appraisal on growth, digestibility, body composition, and hematobiochemical profile

Abstract

Introduction: Linseed or flaxseed (Linum usitassimum L.) contains a prospective source of protein and energy to be utilized in animal feed. This study aimed at re-cycling and value-addition of Linseed Oil Cake (LOC) for formulation of non-conventional carp diets. Methods: The LOC was bio-processed through solid state fermentation (SSF) with a fish gut bacterium, Bacillus pumilus (KF640221). Nine experimental sets of diets were formulated using raw (R1-R4) and SSF-processed (F1-F4) LOC at 10%, 20%, 30% and 40% levels substituting fishmeal as well as other ingredients in a reference diet, and rohu, Labeo rohita fingerlings (2.08±0.03 g) were fed for 70 days feeding trial. Growth, carcass composition, activities of digestive enzymes, digestibility and haemato-biochemical parameters were studied following standard methodologies. Results: SSF significantly (P< 0.05) improved crude protein along with amino acids, whereas crude fibre and antinutritional factors were reduced considerably. Experimental diets were isocaloric (4.8 kcal) and isonitrogenous (36%). Diets with bio-processed LOC had significantly better performance than the raw LOC. Fish fed diet F3 with 30% fermented LOC resulted in the highest weight gain (6.25 ± 0.09 g), specific growth rate (% day -1) and carcass protein deposition (16.77±0.34%). Activities of the digestive enzymes (amylase, lipase and protease) were also significantly (P[removed]