GROWTH, NUTRIENT UTILIZATION AND BODY COMPOSITION OF JUVENILE BAGRID CATFISH, CHRYSICHTHYS NIGRODIGITATUS (ACTINOPTERYGII: SILURIFORMES: CLAROTEIDAE), FED DIFFERENT DIETARY CRUDE PROTEIN LEVELS

The African bagrid catfish, Chrysichthys nigrodigitatus (Lacepede, 1803), is an omnivorous species cultured in both fresh and brackish waters because of its good growth rate, excellent taste, and high market demand. There has been little nutritional work on this economically important species. This study was designed to determine the effects of varying dietary crude protein levels on growth, nutrient utilization and body composition of juvenile C. nigrodigitatus.Materials and Methods. One hundred and twenty fish with an initial mean weight of 21.33 ± 0.48 g were divided randomly among 12 tanks for triplicate groups that were fed diets containing 20%, 25%, 30%, and 35% crude protein (CP). Feed consumption and fish weight were measured biweekly for eight weeks, after which proximate composition of the fish was determined.Results. Fish fed the 35% CP diet had the best growth performance and nutrient utilization (P < 0.05), with a mean weight gain of 88.3% ± 0.2%, feed conversion ratio (FCR) of 2.60 ± 0.12, and protein efficiency ratio (PER) of 1.10 ± 0.05. The least weight gain (32.1% ± 0.9%) and poorest FCR and PER (5.70 ± 0.06 and 0.87 ± 0.01, respectively) were observed in fish fed the 20% CP diet. Body protein content was not affected by diet, but body lipid increased significantly (P < 0.05) with increasing dietary protein levels. Conclusion. C. nigrodigitatus juveniles will grow best when fed diets containing at least 35% CP.