Dietary pineapple peel ethanolic extract alleviates crowding stress in Labeo rohita fingerlings with enhancement of growth performance and IGF-1 expression, physio-biochemical profile, antioxidant status and immunological responses

Crowding stress in intensified aquaculture system reduces growth of fish. However, dietary pineapple peel ethanolic extract derived bioactive compounds are expected to minimize stress with augmented fish production. Therefore, a 60-day study with dietary pineapple peel ethanolic extract (PPEE) at 0, 0.5 and 1 % levels evaluated growth performance and physio-immunological responses of Labeo rohita fingerlings reared under different stocking densities (10, 15 and 20 fish/75 L). Fish fingerlings (405 numbers) of 4.15 ± 0.006 g were distributed among nine groups in triplicate following 3 (PPEE level) × 3 (stocking density) factorial design. Three isonitrogenous (30 % crude protein), isolipidic (6 %) and isocaloric (370 kcal DE/100 g) diets were prepared and fed respective groups on satiation basis twice daily. High stocking density significantly (p < 0.05) reduced final body weight, weight gain percentage, specific growth rate, hepatic IGF-1 expression, whole-body crude protein, lipid and total carbohydrate, intestinal protease and lipase activities, serum proteins and total immunoglobulin and respiratory burst activity (NBT) and increased feed conversion ratio and hepatic superoxide dismutase and catalase activities of fish. However, irrespective of stocking density, 1 % dietary PPEE could enhance the growth performances and physio-immunological responses of fish. In conclusion, feeding of PPEE at 1 % level can sustain intensified aquaculture production.