Synergistic utilization of shrimp shell waste-derived natural astaxanthin with its commercial variant boosts physio metabolic responses and enhances colouration in discus (Symphysodon aequifasciatus)

Abstract This study investigated the effect of dietary supplemented synthetic, and shrimp shell meal (SSM) derived natural astaxanthin combination on growth, digestive and metabolic enzyme activities, antioxidative status, physio-metabolic responses, and skin colouration of high valued discus (Symphysodon aequifasciatus) advanced juveniles reared in captive condition. Four isonitrogenous (50% crude protein), isolipidic (9% ether extract), and isocaloric (around 400 kcal digestible energy/100 g) experimental diets viz. Control (only synthetic astaxanthin, without SSM), T1 (15% SSM + synthetic astaxanthin), T2 (20% SSM + synthetic astaxanthin), T3 (25% SSM + synthetic astaxanthin) were prepared and fed to satiation level twice daily for 90 days. Results indicated significantly (P