Use of Natural Carotenoid Sources for an Indian Major Carp, Labeo rohita (Hamilton, 1822)

Abstract

A 90-day feeding trial was conducted to determine how natural carotenoid sources influence the growth performance, carcass composition, carotenoid deposition, flesh color, and palatability of an Indian major carp, Labeo rohita. Four diets were formulated: a carotenoid-free control feed (CF) and three carotenoid-supplemented feeds containing 5% tomato (TEF), 5% carrot (CEF), and a combination of 2.5% tomato plus 2.5% carrot (TCEF). Fish were randomly distributed into four treatments with triplicate groups and fed to apparent satiation twice daily. Standard procedures and formulas were used to measure growth parameters, including mean weight gain (MWG), specific growth rate (SGR), feed conversion ratio (FCR), and survival, along with proximate compositions, carotenoid content, coloration and palatability attributes (flavor, taste, and texture) of fish flesh. Fish fed the CEF diet exhibited significantly (p<0.05) higher MWG, PWG, and SGR, and a lower FCR compared with other treatment groups. No significant differences (p>0.05) were found in proximate composition among the treatments. Carotenoid accumulation was greatest in CEF, followed by TCEF and TEF. Color measurements showed that fish receiving carotenoid-enriched diets, particularly CEF and TCEF, had significantly elevated lightness (L*), redness (a*), yellowness (b*), and chroma (C*) values (p<0.05). Palatability evaluation further confirmed a stronger preference for the fish fed with CEF, while the control fish scored the lowest. Overall, the results indicate that dietary inclusion of 5% carrot is highly effective in enhancing growth, pigmentation, and palatability in L. rohita.