Dietary chromium polynicotinate improves growth performance and feed utilization of juvenile golden pompano (Trachinotus ovatus) with starch as the carbohydrate

Abstract

This study was conducted to determine if the level of dietary chromium polynicotinate (Cr-Nic) affects growth and feed utilization of juvenile golden pompano (Trachinotus ovatus). Fish were fed one of six diets each containing 42% crude protein (CP) and supplemented with 0 (42% CP-basal-0), 5, 10, 20, 40 or 80 mg of Cr-Nic kg−1. A diet containing 48% CP and without Cr-Nic supplementation (48% CP-basal-0) was also formulated. Wheat starch was used as the carbohydrate source for each diet. The treatment diets were fed to triplicate groups of pompano fish with initial body weights of 10.8 ± 0.18 g for 8 weeks. Fish fed diets supplemented with 10 mg kg−1 Cr-Nic had the highest weight gain percentage (WG%), which was significantly higher than that of fish fed the 42% CP-basal-0 diet. The feed efficiency (FE) of fish fed the 48% CP-basal-0 diet was higher than that of fish fed the 42% CP-basal-0 diet. However, there was no significant difference in FE among fish fed the 48% CP-basal-0 diet and 42% CP-diets that had been supplemented with Cr-Nic. Protein efficiency ratio (PER) was highest for fish fed diets supplemented with 10 and 20 mg kg−1 Cr-Nic, followed by those containing 5, 40, 80 mg kg−1 Cr-Nic and the 48% CP-basal-0 diet. It was lowest for fish fed the 42% CP-basal-0 diet. Analysis of WG by second-order regression indicated that the optimal dietary level of Cr-Nic for T. ovatus is 16.0 mg kg−1. Thus, based on the results of this study, the minimum Cr-Nic requirement was established for golden pompano at 16 mg kg−1 and suggested to be supplemented in diets for this species.