Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body...Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body weight per day for 4 weeks, and then to satiation for the remainder of the experiment. During the first 4-week period, there was a curvilinear relationship between growth rate and ration size. Fish fed 0.5% and 1.5% rations displayed compensatory growth response of 2 weeks duration during realimentation. The weight-adjusted growth rate of fish fed at 3% ration was not significantly different from that of the controls by the end of the experiment, when none of the treatment groups had caught up in body weight with the controls. Hyperphagia was observed for the first 2 weeks of realimenatation in fish previously fed at 3% ration, but persisted for the whole realimentation period in groups previously fed at 0.5% and 1.5% rations. None of the feed restricted groups showed improved digestibility, feed efficiency, or protein and energy retention efficiency.展开更多
Feed restriction is a common practice to reduce post weaning digestive disorders in rabbits and to get carcasses with less fat. Hydric restriction is commonly used to induce feed restriction in growing rabbits. Two hy...Feed restriction is a common practice to reduce post weaning digestive disorders in rabbits and to get carcasses with less fat. Hydric restriction is commonly used to induce feed restriction in growing rabbits. Two hydric restriction times （2 h and 4 h per day, continuously） were used in our trial carried in good sanitary conditions. Thirty six rabbits were divided at weaning （28 days） into three groups： R2 with restricted access to drinking water from 35 days to 80 days age of 2 h per day （from 8 a.m. to 10 a.m.）, R4： access to drinking water 4 h per day （from 8 a.m. to 12 a.m.） and T （control group） with unlimited access to drinking water. Six animals from each group were slaughtered at 80 days of age. Carcass measurements and meat quality were studied. Histological study for kidneys was carried out. Relative weight of gastrointestinal tract increases with the degree of restriction： 16.5, 18.4 and 18.9 for T, R4 and R2, respectively （P 〈 0.05）. Perirenal fat was lower in restricted groups but differences were not statically significant. Scapular fat decreases of 2/3 or 1/3 respectively with limiting access to drinking water of 2 h or 4 h per day. Compared to control group （T）, meat of restricted groups contains more water： 70.3%, 70% and 69.3% respectively for R4, R2 and T （P 〈 0.01）. The same tendency was observed for proteins： 19.2%, 19.3% and 17.7% for groups R2, R4 and T. Fat decreases in meat of restricted animals： 8.4%, 8.2% and 8.1% respectively for T, R4 and R2 （P 〈 0.05）. Water restriction induced decrease of carcass and meat adiposity. There were no differences between pH post mortem and pH ultimate （after 24 h） between the three groups. Hydric restriction does not effect on kidney histology.展开更多
基金Supported by the State Key Laboratory of Freshwater Ecology and Biotechnology of China and Shanghai Fisheries University (Grant No. 200015).
文摘Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body weight per day for 4 weeks, and then to satiation for the remainder of the experiment. During the first 4-week period, there was a curvilinear relationship between growth rate and ration size. Fish fed 0.5% and 1.5% rations displayed compensatory growth response of 2 weeks duration during realimentation. The weight-adjusted growth rate of fish fed at 3% ration was not significantly different from that of the controls by the end of the experiment, when none of the treatment groups had caught up in body weight with the controls. Hyperphagia was observed for the first 2 weeks of realimenatation in fish previously fed at 3% ration, but persisted for the whole realimentation period in groups previously fed at 0.5% and 1.5% rations. None of the feed restricted groups showed improved digestibility, feed efficiency, or protein and energy retention efficiency.
文摘Feed restriction is a common practice to reduce post weaning digestive disorders in rabbits and to get carcasses with less fat. Hydric restriction is commonly used to induce feed restriction in growing rabbits. Two hydric restriction times （2 h and 4 h per day, continuously） were used in our trial carried in good sanitary conditions. Thirty six rabbits were divided at weaning （28 days） into three groups： R2 with restricted access to drinking water from 35 days to 80 days age of 2 h per day （from 8 a.m. to 10 a.m.）, R4： access to drinking water 4 h per day （from 8 a.m. to 12 a.m.） and T （control group） with unlimited access to drinking water. Six animals from each group were slaughtered at 80 days of age. Carcass measurements and meat quality were studied. Histological study for kidneys was carried out. Relative weight of gastrointestinal tract increases with the degree of restriction： 16.5, 18.4 and 18.9 for T, R4 and R2, respectively （P 〈 0.05）. Perirenal fat was lower in restricted groups but differences were not statically significant. Scapular fat decreases of 2/3 or 1/3 respectively with limiting access to drinking water of 2 h or 4 h per day. Compared to control group （T）, meat of restricted groups contains more water： 70.3%, 70% and 69.3% respectively for R4, R2 and T （P 〈 0.01）. The same tendency was observed for proteins： 19.2%, 19.3% and 17.7% for groups R2, R4 and T. Fat decreases in meat of restricted animals： 8.4%, 8.2% and 8.1% respectively for T, R4 and R2 （P 〈 0.05）. Water restriction induced decrease of carcass and meat adiposity. There were no differences between pH post mortem and pH ultimate （after 24 h） between the three groups. Hydric restriction does not effect on kidney histology.
