Effect of Dietary Supplementation of Annatto (Bixa orellana) Seed Meal on Growth, Survival, Whole-Body Composition and Total Carotenoid Content of Rosy Barb, Puntius conchonius

Abstract

A 65-day feeding trial was performed on rosy barb, Puntius conchonius to evaluate the effects of diets supplemented with 0%(control), 0.5%(B1), 1%(B2), 1.5%(B3), 2%(B4) and 2.5%(B5) annatto seed meal and with 0.01% lucantin pink(positive control) on growth, survival, proximate body composition and total carotenoid content in fish skin and muscle tissue. For the study, 21 aquaria were used, each with 30 juveniles of uniform weight (1.51±0.01gm). At the end of feeding experiment, significantly highest final body weight (2.66±0.01gm) weight gain(1.04±0.01gm), final length (5.16±0.01cm), specific growth rate (SGR) (0.88±0.01%) and condition factor (CF)(1.871±0.003) was found in the fishes those were fed with experimental diet B3, followed by B2 set, B1 set and the lowest values were noted in B5 set. Feed conversion ratio (FCR) of the control fishes was 0.108±0.001 whereas the best FCR was observed in fishes of B3 set (0.079±0.001) and the poorest in B5 diet set (0.193±0.001). Total carotenoid content in fish skin and muscle was highest in B3 set (9.63±0.13), followed by B2 set (7.03±0.10), B1 set (6.21±0.14) and the lowest value was found in B5 set (2.11±0.28). No significant effect of dietary treatments was noticed in whole-body composition of experimental fishes. As survival was 100% in B1, B2 and B3 sets, so annatto seed meal could be supplemented safely up to 1.5% in the diet of rosy barb to ensure enhanced skin pigmentation, growth, feed utilization and survival. Thus, annatto seed meal could be successfully added as an alternative, cost-effective, easily accessible natural carotenoid source in rosy barb diet to enhance skin coloration.