The Study Of Appropriate Dietary Metabolizable Energy And Crude Protein For Guangxi Guixiang Chicken

The effect of ratio of dietary energy and protein level o to the produ ction performance, nutrition digestion rate in three different growth period of Guangxi Guixiang chicken was studied to confirm a app ropriate level of energy and protein. The slaughter performance and the growth law were also determined.Experiment design of two factors, metabolizable energy and protein le vel, with three levels for each was conducted for every growth stages. Ea ch of the obtained9furmulas was repeated3times. The dietary metaboliz able energy levels of fledging stage(0-4weeks old) were11.57MJ/kg、12.17MJ/kg and12.77MJ/kg together with the dietary protein levels of17.5%,19%and20.5%; the dietary metabolizable energy levels of growing stage (5～13weeks old) were111.65MJ/kg、12.25MJ/kg and12.85MJ/kg together with the dietary protein levels of15%,16.5%and18%; the diet ary metabolizable energy levels of fattening period (14～17weeks old) were12.36MJ/Kg、12.96MJ/kg and13.56MJ/kg together with protein levels of14.2%,15.7%and17.2%.In the end of the every stage, chose3test chicken of which the we ights are in the neighborhood of the middleweight for the Metabolic test. At the end of the feeding experiment, chose4test chicken of which the weights are in the neighborhood of the middleweight for the slaughter tex t as well as chosing4normally fed chicken for the determination of the slaughter performance. It is on the base of the weights of e very week that the growth law of the Guangxi Guixiang chicken w as studied.Results including:1.The variation tendency of the body weight was best fitting with Bert alanffy curve which could be used to predicted indexes such as body weig ht for instructing in production while Logistic curve was more fitting in pr ediction of the growth inflection point in stages.2. In the fledging stage(0-4weeks old), dietary metabolizable en ergy decreased significantly feed intake and the ratio of feed to gai n, but had no significant influence in daily weight gain and weigh t. Increased significantly the apparent digestibility of gross energy, crude pr otein and ether extract. The crude fiber digestibility at high metabolizable e nergy level was higher than which at a low metabolizable energy level sig nificantly while the apparent digestibility of calcium at a medium metaboliz able energy level was higher than which at a high or a low metabolizable energy level. The increasing of the dietary protein level caused a sig nificant reduce in the apparent digestibility of crude protein and a signi ficant increase in the apparent digestibility of crude fiber but not signific ant in the rest indexes. In conclusion, the optimal dietary energy and protein level was confirmed as high metabolizable enery(12.77MJ/kg) and high protein(20.5%).3.In the growing stage (5-13weeks old), as the increasing of the dietary metabolizable energy level, the daily weight gain and h ad a significant increase and the weight also increased as a result. The feed intake and the feed-weight ratio had a significant decrease. At a high level of metabolizable energy, the apparent digestibility of the nutrition were higher than that at a low level significantly except calcium a nd phosphorus.The dietary protein level had no significant effect on daily weight ga in, weight, feed intake or the feed-weight ratio. Compared with lo w protein content, the apparent digestibility of gross energy and crude pro tein of which had high protein content had a significant decrease while no significant effect was shown in the apparent digestibility of Ether extrac t, crude fiber, calcium and phosphate. In conclusion, the opti mal dietary energy and protein level was confirmed as high metaboli zable enery(12.85MJ/kg) and high protein(18%).4.In the fattening period (14～17weeks old), the highest avera ge weight was the high-energy-high-protein group of1656.57g whil e the lowest average weight was low-energy-low-protein grop of1544.80g with a difference of111.77g (7.24%) between the highest a nd the lowest.The increasing of the dietary metabolizable energy level caused a increase in daily weight gain and a significant increase in the app arent digestibility of gross energy and crude protein but not significant in e ther extract, calcium or phosphate. The feed intake, feed-weight r atio, and the apparent digestibility of crude fiber of the high-energy gro up were significantly lower than the low-energy group while there’s no sig nificant difference in the apparent digestibility of calcium or phosphate.The medium level of protein content has a significant increase in daily weight gain.But there is no significant difference has shown in production performance such as weight, feed intake or feed-weight ratio or in the apparent digestibility of ether extract, crude fiber or phosphate. The medium level of the dietary protein might increase the apparent digesti bility of gross energy but decrease that of protein. The apparent digestibilit y of calcium in the medium protein group was higher than that in the hig h group. In conclusion, the optimal dietary metabolizable energy and p rotein content was13.56MJ/kg,15.7%.5. The dietary metabolizable energy and protein level had no sig nificant effect to the slaughter performance of Guangxi Guixiang ch icken. Compared with hen, the cock has a low slaughter performa nce significantly, and a higher the eviscerated weight with giblet a nd the leg muscle rate.