Efficacy of spirulina (Arthrospira platensis) meal with fish protein hydrolysate as sustainable fish meal alternative in striped murrel (Channa striata) diets

Abstract

A 60-day feeding trial was carried out to assess the effects of substituting fish meal with graded levels of algae meal (AM) (Arthrospira platensis) alone or supplemented with fish protein hydrolysate (FPH) on growth performance and nutrient utilization of striped murrel (Channa striata). Five isonitrogenous (44% crude protein), isolipidic (11% crude lipid), and isoenergetic (18 MJ/kg gross energy) diets viz. Control (consists of 35% fish meal), 25% algae meal (25AM), 50% algae meal (50AM), 25% algae meal and 1% FPH (25AM + FPH), and 50% algae meal and 1% FPH (50AM + FPH). A total of four hundred and fifty (450) juveniles of Channa striata (average weight: 9.85 ± 0.30 g) were randomly stocked in 15 experimental cages (1 m × 1 m × 1.5 m) at a stocking density of 30 fish/cage in triplicates. The juvenile striped murrel were fed three times a day until apparent satiation (08:00, 13:00, and 18:00 h). Among all the dietary groups, fish fed the 25AM + FPH diet showed significantly higher (p < 0.05) growth performance and nutrient utilization than fish fed the other diets. The inclusion of AM alone or in combination with FPH diets did not affect the whole-body proximate composition and hemato-biochemical profile of striped murrel (p > 0.05). Significantly (p < 0.05) higher digestive enzyme and antioxidant enzyme activities, intestinal villi length and width, and IGF-1 gene expression were found in fish fed the 25AM + FPH diet which was not different from the control diet. In conclusion, algae meal supplemented with FPH (25AM + FPH) can replace dietary fish meal up to 25% without affecting growth, nutrient utilization, whole-body composition, digestive enzyme activities, intestinal villi length and width, hemato-biochemical responses, and IGF-1 expression in striped murrel. However, replacing more than 25% of fish meal with AM alone or combination of AM and FPH adversely affected the growth performance and nutrient utilization in striped murrel (C. striata). Therefore, this research suggests the potential of combining AM and FPH as a sustainable alternative to fishmeal. This combination with an inclusion level of 25% proved beneficial for C. striata, demonstrating its viability for future feed formulations.