Effects Of Dietary Energy To Protein Rations On Growth And Digestive Enzymes Activities Of Procambarus Clarkii

The juvenile procambarus clarkii with initial mean body weight of 2.39±0.37g were randomly divided into 9 groups and fed diets containing 26%,29%and 32%crude protein with dietary energy to protein ratios of 36,40 and 44kJ/g at each protein level in the experiment,which lasted 49 days including the provisional feeding test 7 days and the formal one 42 days to study the effects of dietary energy to protein ratios on growth,digestive enzymes activities,meat composition,and diet digestibility of Procambarus clarkii,the aim is to provide the theoretical basis for the feed formulation of Procambarus clarkii.1.Effects of dietary energy to protein ratios on growth of Procambarus clarkiiThe results showed that the energy to protein ratios in the diet had significant effects on the growth and feed utilization of Procambarus clarkii.The weight gain multiples,SGR,and PER were increased and the FCR was decreased with the increase of protein content at levels of 26%-29%in diet.But the same growth indexes had converse changes with the increase of energy to protein ratios at levels of 36-44kJ/g in the diet.The seventh group had the best growth performance in the experiment.2.Effects of dietary energy to protein ratios on digestive enzymes activities of Procambarus clarkiiThe effects of different energy to protein ratios in the diet on the activities of digestive enzymes of procambarus clarkii were compared and analyzed.The results showed that the activities of protease in hepatopancreas and stomach became higher significantly with the increased of dietary protein,under the same protein level,the protease avtivities had no regularly changes but the lipase activities in hepatopancreas and stomach became higher with the increase of energy to protein ratios in the diet.Different protein content and energy to protein ratios in the diet had no significant effects on the amylase activities in hepatopancreas,and amylase activities in stomach and intestine didn' t change regularly,either.3.Efects of dietary energy to protein ratios on meat composition of Procambarus cIarkiiThe results showed that the diet had no significant effects on water and protein content in the meat,but protein content was increaed and water content was decreased only a little with the increase of protein content in the diet.Protein levels and energy to protein ratios in the diet had the same effects on fat and ash content in the meat,fat and ash content in the meat was increased with increase of energy to protein ratios and protein content in the diet respectively.4.The comparision of digestibility of different energy to protein ratios dietsThe comparision of digestibility of different energy to protein ratios diets illustrated that protein content in the diet had no significant effects on the protein and fat digestibility but had significant effects on the total digestibility.The fat and total digestibility was increased while the protein digestibility was decreased with the increase of energy to protein ratios in the diet.the results showed that the optimum protein content was28.62～32.24%and energy to protein ratios was34.67～40.42KJ/g in the diet for Proeambarus clarkii...