Utilization of Sweet Potato as Pigment Source in Siamese Fighting Fish (Betta splendens) Feed

Abstract

This study investigated the effect of different sweet potato varieties as dietary pigment sources on the coloration of Siamese Fighting Fish (Betta splendens). The experiment was conducted as a completely randomized design (CRD) with four treatments and three replicates. The experimental feed consisted of; control feed, 5 % orange sweet potato (OrSP), 5 % yellow sweet potato (YeSP) and 5 % purple sweet potato (PuSP). The experimental feeds were formulated with 31.18-32.01 % crude protein, 6.73 - 7.04 % crude fat and total carotenoids in control, OrSP, YeSP and PuSP were 15.63, 42.61, 38.79 and 32.32 mg/kg, respectively. Two-month male fishes were obtained from a reliable commercial farm and acclimated to the rearing environment. After the 8 weeks rearing period, the results showed that the final average weight, final average length, average daily gain, weight gain, specific growth rate and feed conversion ratio (FCR) were not significantly different between treatment groups (p > 0.05). However, dietary supplementation with sweet potato affected the color expression and carotenoid accumulation by Betta splendens. The lightness(L*) of fish fed with the control feed showed the highest value (p ≤ 0.05). The redness (a*) of fish fed with 5 % OrSP and 5 % YeSP was higher than in the other treatments (p ≤ 0.05) and the yellowness (b*) of fish fed with 5 % OrSP showed higher values than in the other groups (p ≤ 0.05). The results of carotenoid accumulation in each organ increased in all treatment groups. After 8 weeks, the fish fed with 5% OrSP showed the highest carotenoid accumulation in skin and scale, dorsal fin, anal fin and caudal fin as compared to the other groups (p ≤ 0.05).