Dietary Protein Requirement of Juvenile Dotted Gizzard Shad <i>Konosirus punctatus</i> Based on the Variation of Fish Meal

Abstract

An 8-week feeding trial was conducted to investigate the effects of dietary protein levels on growth performance, feed utilization, and energy retention of juvenile dotted gizzard shad Konosirus punctatus based on the variation of fish meal. Fish meal was used as the sole protein source; five semi-purified diets were formulated with varying crude protein (CP) levels of 22.52%, 28.69%, 34.85%, 38.84%, 45.78% (CP1-CP5 diets). A total of 300 uniform juveniles with initial body weight 3.61 ± 0.20 g fish−1 were randomly divided into five groups with three replicates in each group. The results showed that different CP levels did not significantly affect the survival of juvenile K. punctatus (p > 0.05). The values of weight gain (WG) and specific growth ratio (SGR) showed a general enhancing trend and then weakened with increasing dietary CP levels (p > 0.05). Feed utilization also improved with increasing dietary CP levels (p > 0.05), and the optimal feed conversion ratio (FCR) value was found in fish fed the diet with CP3 (p > 0.05). The rise of dietary CP from 22.52% to 45.78% enhanced the daily feed intake (DFI) and protein efficiency ratio (PER) values of K. punctatus (p p p > 0.05). The activity of lipase in CP3 and CP4 diets was significantly higher than that of the CP1 diet (p p K. punctatus is about 31.75–33.82% based on the variation of fish meal.

Keywords

• <i>Konosirus punctatus</i>
• growth
• feed utilization
• body composition
• energy retention
• dietary protein levels