Study On Feeding Strategies And Gonadal Development Rule Of Russian Sturgeon

Feeding strategy is the most important factor affecting the growth of fish. This paper studies the effects of feeding rate and frequency of 2-3 age juvenile Russian sturgeon(Acipenser gueldenstaedtii) growth, in order to find the optimum feeding strategies to improve the economic and ecological benefits.1. Effect of feeding rate on growth, body composition and haematological norm of Russian sturgeon reared in net pensThis study describes the effects of feeding level on growth, body composition and main blood index in two year Russian sturgeon reared in net pens. Feeding rates were 0.7%(F1)、0.8%(F2)、0.9%(F3)、1.0%(F4)and 1.1%(F5)body weight day-1(BW/day), respectively. Analysis of variance showed that weight gain rate(WGR) and specific growth rate(SGR) were significantly(P < 0.05) higher at F5 than F1 body weight day-1. There was no change in survival rate(SR) and condition factor(CF) during the experiment(P > 0.05). Gonadosomatic index(GSI) were significantly(P < 0.05) higher at F5 and F3 BW/day than F1 BW/day. Splenosomatie index(SSI) was not significantly different between any treatments(P > 0.05). Moisture in Russian sturgeon muscle was significantly(P < 0.05) higher at F1 BW/day than F5 BW/day. Crude ash at F5 and F3 BW/day was significantly(P < 0.05) lower at F2 and F1 BW/day, and significantly higher at F4 BW/day. Crude protein and Crude lipid was not significantly(P > 0.05) different at all feeding rate, respectively. There was no change in red blood cell(RBC) amount, white blood cell(WBC) amount, total cholesterol(TC) during the experiment(P > 0.05). Triglyceride(TG) was significantly(P < 0.05) higher at F4 and F3 BW/day than F1 BW/day. It suggests that F1 BW/day is not the optimum feeding rate for two year Russian sturgeon reared in net pens.2. The analysis of gastric evacuation characteristics and associated mathematical models in juvenile Russian sturgeonTo examine the change traits of chyme mass and fit to the gastric evacuation data in juvenile Russian sturgeon, one hundred and twenty experimental fish(10.47 ± 2.03) g were removed from the various intervals(0, 2, 4, 6, 8, 10, 12, 14, 16, 20, 24, 28h) after satiation feeding at 23℃. The wet mass of the chyme were determined and the applicability of three mathematical models was compared by the good of fitness fitted to gastric evacuation data in juvenile Russian sturgeon. The results of present study showed that, the wet mass of remaining food in stomach as well as percentage of food residual decreased profoundly as postprandial time increased. Though three mathematical models all fitted well the gastric evacuation data, there still were several significant differences among these regression results. As mentioned above, it suggested that the best mathematical model fitted to gastric evacuation data in juvenile Russian sturgeon was the square-root model and its regression equations for wet mass of the chyme mass were y 0.5= 1.912-0.066t( R2= 0.988, P < 0.001). The gastric evacuation rate of juvenile Russian sturgeon was among the range of 0.066g/h, and the 80% of gastric evacuation time was among the range of 15 h, in other words, after feeding about 15 h resume the appetite.3. Effects of feeding frequency on growth and body composition of juvenile Russian sturgeon reared in net pensAn experiment was conducted to determine the effects of optimal feeding frequency on growth performance, feed conversion efficiency and body composition in juvenile Russian sturgeon. Four feeding frequencies of one(F1), two(F2), three(F3) and four(F4) times a day were evaluated as treatments in triplicate for a period of 35 days. At the end of the experiment, weight gain rate(WGR), specific growth rates(SGR) and efficiency of feed conversion(EFC) were highest in F2 and lowest in F1. Feed conversion efficiency ranged between 35.76±1.07 and 45.44±0.45. There were no significant differences in either moisture or lipid content of the muscle. Protein content increased with increasing feeding frequency. It is concluded that the Russian sturgeon juveniles can achieve maximum growth performance and better nutrient utilization when they are fed a given ration two times a day.4. The comparison of gonadal development rule between Russian sturgeon and other there sturgeonsTo investigate the development of the rule of the Russian sturgeon gonad under culture conditions, and to identify the key technical and economic indicators of the minimum age of sexual maturity and sexual maturity cycle, improve the predictive ability of caviar production. In Hangzhou Qiandaohu Xunlong Sci-tech Co., Ltd. 2007-2012 sexually mature sturgeon processing ratio and mortality were studied based on the biological characteristics of sturgeon species, breeding population size and breeding age and individual composition of the underlying data prediction model caviar production, scientific forecasting trends caviar production. For the future development of the analysis, prediction and control provides important references.