Effects Of Supplemental Protein On Growth And Digestive Enzyme Activities Of Jade Perch

A quantitative dietary requirement of protein has been determined for Jade Perch, Scortum bacoo, Using a kind 'of exclusive source of white fishmeal. The effects of dietary protein levels had been studied on body composition, muscle composition, protein storage in liver and digestive enzyme activities.This experiment includes feeding trial and slaughter trial. Feeding trial of 8 weeks was conducted under the condition of controlling water temperature in the greenhouse, used 105 healthy Jade Perch (mean weight 104.13+0.46g). Fifteen experimental net cases were divided into five experimental treatments with triplicate groups. Every case stocked seven Jade Perch by fed purified diets containing graded levels of protein (23.64%, 28.45%, 33.50%, 37.04%, 41.62%). During feeding trial, changing water was designed periodically and .experimental fishes were fed twice per day. Jade Perch was weighted every two weeks, to calculate gain, feed intake and feed conversion ratio (FCR). When the feeding trial was terminated and nine fishes (three replicates of 3 fishes each) from each treatment were selected based on similar live weight and slaughtered to determine carcass characteristics. At the same time, samples required were collected.The results of feeding trial showed that total weight gain, daily weight gain andpercent body weight gain were significantly (p<0.01) excellent with increasing dietary protein level up to 33.50% than dietary protein level up to 23.64%, and significantly (p<0.05) excellent than dietary protein level up to 28.45%. At the same time, feed conversion ration (FCR) and feed gain ration were improved with in creasing dietary protein level .The dietary level required for Jade Perch of optimal growth was found to be 33.94%, based on the broken-line model analysis of percent body weight increase. Protein efficiency ratio (PER) and net protein utilization decreased with increasing dietary protein level and had no obvious effects among groups (p>0.05).The results of slaughter trial showed that the dietary protein 33.50% group exhibited very significantly different effect (p<0.01) than the dietary protein 23.64% group and significantly different effect (p<0.05) than the dietary protein 28.45% group on the view of Jade Perch's body protein content. Body fat content decreased with the increase of dietary protein level. The dietary protein 41.62% group exhibited significantly (p<0.05) effect on body fat content than the dietary protein 23.64% group. At the same time, the dietary protein 41.62% group exhibited significantly (p<0.05) effect on body ash content than the dietary 23.64%, 28.45% and 33.50% groups, respectively. Assaying on muscle composition and liver gained similar results to body composition.The results of selected viscera indicated that protease activities of stomach and intestines in 41.62% group were higher 67.40% (p<0.01), 62.93% (p<0.01), 56.75% (p<0.05) than 23.64%, 28.45% and 33.50% groups, respectively. But lipase activities and amylase activities of stomach and intestines had no significantly effects among groups with the increase of dietary protein levels.The results obtained from the research implicated that CP requirement for maximum growth of Jade Perch is 33.94%. To meet the need of body CP, muscle CP and liver CP storage, the supplemental CP lowest level should be 33.50% as shown in the experiment. As a result, this article suggested that the optimal dietary CP level for Jade Perch (mean body weight lOOg to 200g) should be 33.94%.