| This topic has focused on two aspects. One is the the evaluation of the feed nutrition,and the other one is study on the mechanism of the difference of the endogenous energy between Hy-Line Brown and Nongda 3 laying hens.As for the first aspect of the study, the changes of the new-harvest corn and wheat after ripening and the effects of the different stages of the grains after-repining on the metabolizable energy of the poultry were explored with the facts that the using of the fresh grains can reduce the production performance of the poultry.Firstly, 4 new-harvest wheat samples after air drying were selected to study the effects of different storage stage with 20 d, 40 d, 60 d and 90 d after harvesting on the metabolizable energy of adult Hy-Line Brown with the force feed experimental method. The results showed that the NSP reduced insignificantly with time going and there was no significant influence between the storage stages and the metabolizable energy of adult Hy-Line Brown roosters.Secondly, 6 corn samples and 2 wheat samples with the moisture of more than 20% after harvesting were selected. We studied the changes of the corn and wheat samples during different after-ripening stages and the effects on the ME of the broilers of 10 d and 20 d with the experimental methods of simulation the ripening of the grains in the lab.The results showed that the amylase activity of corn grain and NSP content of wheat were significantly reduced while the concentration of soluble protein of corn grain was significantly increased,and the resistant starch content of corn and wheat was decreased significantly, as for the result,the corn significantly increased the AME of broiler at 10 days of age. Thus this proved that with the new post-harvest grain ripening stage going, the physical and chemical properties were changed and the grain nutrition resistance reduced so it became more conducive for digestion and utilization of nutrients in cereals.As for the second aspect of the research, firstly the effects of the corn samples with different V-W on the metabolizable energy of adult Hy-Line Brown and Nongda 3 roosters were explored. Then as for the phenomenon that Nongda 3 adult roosters had significantly higher endogenous energy than the Hy-Line Brown roosters, the mechanism was explored.Firstly, 4 corn samples with different V-W of 719g/L, 724g/L, 731g/L and 747g/L were selected to study the effects of different V-W on the metabolizable energy of adult Hy-LineBrown and Nongda 3 roosters with the force feed experimental method. The results proved that there was no significant difference on the AME and TME of both the adult roosters.But we found that the EE of the Nongda 3 roosters is significantly higher than the EE of the HyLine Brown roosters during the comparison of the EE between the 2 adult roosters.Then as for the phenomenon that Nongda 3 adult roosters had significantly higher endogenous energy than the Hy-Line Brown roosters. We collected the intestinal tracts at 5week?10 week?15 week and 50 week to investigate the intestinal development and enzyme activity. The resulted showed that before 5 week, the proportion of intestinal tracts of Nongda3 roosters was significant higher than Hy-Line Brown. However there had an opposite phenomenon from 10 week. The Nongda 3 roosters had significantly higher duodenum protease activity than the Hy-Line Brown.There was no difference between both the intestine alkaline phosphate in different growth phase acid enzyme staining and it showed that maturity villi epithelial cells did not change significantly, there was no significant difference between length, but Nongda 3 roosters villus height/crypt depth was significantly higher than Hy-Line Brown.In conclusion, the results showed that the renewal of the the intestinal villi epithelial cells of Nongda 3 roosters was more active, the differences of the digestive enzyme activity between the varieties suggested their secretion rate was different, the above two factors resulted in the difference of the EE between Nongda 3 and Hy-Line Brown roosters. |
PDF Full Text Request