Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fe...Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30,each lasted for about 25 minutes,for a total feeding time of 73.2±22.65 minutes per day. At these salinities,there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment,which is significantly higher than those at other salinities. All juveniles survived at salinity 20,and the survivorship was not significantly different from that at 30,but was signif icantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/g BW,average body weight gain of 0.796±0.128 g,gain rate of 87%–96%,and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities( P> 0.05). Highest activities of digestive enzymes(Amylase,Protease,Lipase) and lowest activities of protective enzymes(SOD,PO,CAT) were also obtained on crab juveniles reared at salinity of 20.展开更多
The aim of the present study was to develop a formulated feed for improving skin pigmentation and growth performance of koi carp juveniles. Two experiments were conducted for determination of an optimal dietary astaxa...The aim of the present study was to develop a formulated feed for improving skin pigmentation and growth performance of koi carp juveniles. Two experiments were conducted for determination of an optimal dietary astaxanthin and FM （fish meal） ration for koi carp juveniles. In the first experiment, three isonitrogenous and isoenergetic dietary treatments were designed with three different levels of astaxanthin consisted of 60, 80 and 100 mg/kg and a commercial feed served as a control. For the second experiment, four isonitrogenous and isoenergetic dietary treatments were formulated with graded inclusions of dietary FM replaced from 0% to 60% at 20% increments by SM （soybean meal）, PBM （poultry by-product meal）, and a CD （control diet）. Obtained results demonstrated that skin pigmentation of koi carp juveniles fed the diet containing 80 mg/kg astaxanthin, 36.02% protein, 7.78% lipid, 4.20 Kcal/g GE （gross energy） were more better than those at the diet with lower estaxanthin content and commercial diet. Moreover, the highest growth and feed utilization of fish were observed at this diet with WG （weight gain）, SGR （specific growth rate） and FCR （feed conversion ratio） were 121.80%, 0.95 （%/day） and 1.6, respectively.展开更多
基金Supported by the Science and Technology Innovation Team of Marine Crab Industry in Ningbo City(No.2011B81003)the National Natural Science Foundation of China(No.41276123)+2 种基金the National Spark Plan Program of China(No.2012GA701048)the Key Project of Ministry of Education,Science and Technology(No.212070)the K C Wong Magana Fund in Ningbo University
文摘Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30,each lasted for about 25 minutes,for a total feeding time of 73.2±22.65 minutes per day. At these salinities,there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment,which is significantly higher than those at other salinities. All juveniles survived at salinity 20,and the survivorship was not significantly different from that at 30,but was signif icantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/g BW,average body weight gain of 0.796±0.128 g,gain rate of 87%–96%,and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities( P> 0.05). Highest activities of digestive enzymes(Amylase,Protease,Lipase) and lowest activities of protective enzymes(SOD,PO,CAT) were also obtained on crab juveniles reared at salinity of 20.
文摘The aim of the present study was to develop a formulated feed for improving skin pigmentation and growth performance of koi carp juveniles. Two experiments were conducted for determination of an optimal dietary astaxanthin and FM （fish meal） ration for koi carp juveniles. In the first experiment, three isonitrogenous and isoenergetic dietary treatments were designed with three different levels of astaxanthin consisted of 60, 80 and 100 mg/kg and a commercial feed served as a control. For the second experiment, four isonitrogenous and isoenergetic dietary treatments were formulated with graded inclusions of dietary FM replaced from 0% to 60% at 20% increments by SM （soybean meal）, PBM （poultry by-product meal）, and a CD （control diet）. Obtained results demonstrated that skin pigmentation of koi carp juveniles fed the diet containing 80 mg/kg astaxanthin, 36.02% protein, 7.78% lipid, 4.20 Kcal/g GE （gross energy） were more better than those at the diet with lower estaxanthin content and commercial diet. Moreover, the highest growth and feed utilization of fish were observed at this diet with WG （weight gain）, SGR （specific growth rate） and FCR （feed conversion ratio） were 121.80%, 0.95 （%/day） and 1.6, respectively.
