Physiological condition, digestive enzyme, blood haemato-biochemistry, antioxidant, immune and stress response of juvenile red sea bream (Pagrus major) fed diets containing spent oleaginous yeast

Abstract

A 50 days feeding trail was conducted to evaluate the efficiency of spent oleaginous yeast Lipomyces starkeyi by-product from wheat straw as a probiotic supplement on juvenile red sea bream (Pagrus major). Elements that were investigated includes physiological condition, digestive enzyme, haemato-biochemistry, antioxidant, immune and stress. 300 juvenile P. major (9.13±0.05 g) were randomly distributed into 200 L polyethylene tank (20 fish per tank) in triplicate of 5 treatments; CD1 control (0 g/kg supplement), D2 (1%, 10 g/kg supplement), D3 (1.5%, 15 g/kg supplement), D4 (2%, 20 g/kg supplement), D5 (2.5%, 25 g/kg supplement). The fish were fed twice daily and sampling for weight and length were conducted at 35 and 50 days of the feeding trial. Whole body samples, digestive organs and blood collection was done at the end of the feeding trial. The results of the combine parameters assessed by multivariate analysis revealed that fish group fed on D5 has significantly better performance followed by D4, D2 and D3 compared to the fish group fed the control diet D1 (ANOSIM, P<0.009, r≥0.5). Total cholesterol (T-Cho), derivative of reactive oxygen metabolite (d-ROM), total protein (T-Pro), protease digestive enzyme (D-protease) and alanine aminotransferase (ALT) explained 77.95% dissimilarities between fish group, suggesting the functional properties of the spent oleaginous yeast in modulating and improving these parameters. The fish fed yeast supplement diets showed considerable increase in whole body crude lipid, saturated fatty acid (SFA) and monounsaturated fatty (MUFA) acid with increasing yeast supplement while polyunsaturated (PUFA) reflected the inverse of this relationship. No significant alteration was detected on condition factor (K), relative condition factor (Kn) and, length and weight relationship coefficeint (b) between fish fed all test diets. Survival was not significantly different between treatments. Growth responses, digestive enzyme activity, blood health, antioxidant activity and immune responses were significantly improved in fish fed yeast supplemented diets compared to fish group fed the control diet. The stress tolerance ability was significantly higher in fish group fed yeast supplement diets compared to fish group fed the control diet. These results suggest that, spent oleaginous yeast Lipomyces starkeyi is a potential probiotic supplement for red sea bream with an optimum supplementation at 2.5% of dietary proportion. Data availability statement: The data supporting the findings of this study are available from the corresponding author and may be provided upon reasonable request.

Keywords

• Red sea bream (Pagrus major)
• Growth responses
• Oxidative condition
• Blood status
• Immune responses