Dietary carotenoid supplementation improves fillet appearance, antioxidant status and immune responses in striped catfish (Pangasianodon hypophthalmus) nevertheless the growth performance

Abstract

A feeding trial of 45 days was conducted for delineating the effect of carotenoids on the fillet appearance, antioxidant status and nonspecific immune responses of Pangasianodon hypophthalmus fingerlings. Two hundred and fifty-two fingerlings were randomly distributed into seven different experimental groups in triplicates. Seven isonitrogenous and isolipidic diets were prepared with two levels (150 and 300 mgkg-1) of astaxanthin (T2 & T3), beta-carotene (T4 & T5), canthaxanthin (T6 & T7) and a control diet (T1) without any carotenoids. The experimental fish were fed daily at the rate of 3% body weight in two instalments. At the end of the experiment, the fish were sampled to evaluate the colour and texture parameters, of fillets along with antioxidant and nonspecific immune status of fish. The fillet colour exhibited significantly higher (P<0.05) intensity of redness in the groups fed astaxanthin and a higher yellowish colouration in the beta-carotene fed groups. Significant (P<0.05) reduction in the activities of antioxidant enzymes and a significantly (P<0.05) higher PUFA/SFA ratio was also observed in astaxanthin fed groups. The total erythrocyte count, haemoglobin, respiratory burst, lysozyme activities were also enhanced in both astaxanthin fed groups (T2 & T3). The effect of carotenoids in modulating the texture of pangasiusfillets was diminutive and further, there was little influence of carotenoids on growth. Thus, from this study, it can be concl