Study On Protein Metabolism And Requirement Of Jiangquan White Pig

In this experiment,Jiangquan White Pig was selected as the research object.The effects of dietary protein levels on growth performance,apparent digestibility of nutrients and slaughter performance of Jiangquan White Pig were studied through feeding,digestion and metabolism tests and slaughter comparison experiments,and the protein requirement factorial model of Jiangquan White Pig at different stages was established.Study on the Production Performance of Jiangquan White Pig.A single factor experiment design was used.Thirty-two 35-day-old healthy Jiangquan White weaned piglets with similar parity and weight were randomly divided into four treatments,each with eight replicates.The experiment was conducted in groups and stages.The whole experiment was divided into three stages:nursery period（15³0 kg）,growth period（30⁶0 kg）and fattening period（60⁹0 kg）.The protein levels of each stage were set with gradients of 110%,100%,90%and 80%of the recommended amount,and other nutritional levels were consistent.The results showed that the protein level in the diet significantly affected the average daily gain and feed conversion ratio（P<0.05）of growth period（30⁶0 kg）,fattening period（60⁹0 kg）and whole growth stage（15⁹0 kg）.When protein level was 100%of the recommended amount,feed conversion efficiency and average daily gain were significantly increased.Study on nutrient utilization rate of Jiangquan White Pig.Three digestion and metabolism tests were conducted at the middle stage of each stage with the full fecal and urine collection method,and the formal stage was 7days.The test results show that:The apparent digestibility of nutrients in different stages of Jiangquan White Pig was significantly affected by dietary crude protein level（P<0.05）.With the increase of protein level,the apparent digestibility of dry matter,organic matter,crude fat,crude protein and carbohydrate,the biological value of protein（BV）and net protein utilization（NPU）of Jiangquan White Pig increased first and then decreased.When the protein level was 20.88%,17.93%and 17.93%,the nutrient utilization rate of Jiangquan White Pigs in three stages of nursery period（15³0kg）,growth period（30⁶0 kg）and fattening period（60⁹0 kg）was significantly improved,respectively.Study on slaughter performance of Jiangquan White Pig.After the end of the feeding experiment of Jiangquan White Pig,all 32 experimental pigs were slaughtered.The test results show that:Dietary protein level had significant effects on lean meat rate,fat meat rate,bone rate and skin rate of Jiangquan White Pig（P<0.05）.With the increase of protein level,lean meat rate,bone rate and skin rate gradually increased,and fat meat rate gradually decreased（P<0.05）,and the quality of the carcass was better in the treatment group with the protein level of 110%;dietary protein level could significantly affect body composition of Jiangquan White Pig on the basis of fresh samples（P<0.05）.When the protein level was100%of the recommended amount,the body protein deposition efficiency and meat production performance of Jiangquan White Pig were the highest;the deposition rate of protein in different parts of Jiangquan White Pig was significantly affected by different levels of dietary protein（P<0.05）,and the main deposition site is lean meat.Protein deposition rate of lean meat was highest in the treatment group with 100%protein level as the recommended amount.The maintenance protein requirements of Jiangquan White Pig in the three stages of nursery period（15³0 kg）,growth period（30⁶0 kg）and fattening period（60⁹0 kg）were:4.98 W^0.75,4.62 W⁰.75.75 and 4.50 W⁰.75.75 g/（d·head）,respectively;the protein requirement for1 kg weight was divided into 280,310 and 440 g.Protein requirements can be predicted by the following models:15³0 kg:RCP（g/d）=4.98 W^0.75+0.28 DG;RDCP（g/d）=4.02 W^0.75+0.24 DG;RNCP（g/d）=2.95 W^0.75+0.18 DG30⁶0 kg:RCP（g/d）=4.62 W^0.75+0.31 DG;RDCP（g/d）=3.53 W^0.75+0.23 DG;RNCP（g/d）=2.84 W^0.75+0.17 DG60⁹0 kg:RCP（g/d）=4.50 W^0.75+0.44 DG;RDCP（g/d）=3.06 W^0.75+0.30 DG;RNCP（g/d）=2.21 W^0.75+0.23 DGBased on the factorial model of protein demand of Jiangquan White Pig and referring to the production performance data of Jiangquan White commodity pig in recent 5 years,the feeding standard of Jiangquan White Pig was obtained.The suitable protein levels of Jiangquan White Pig at 15³0 kg,30⁶0 kg and 60⁹0 kg feeding stages were 19.4%,17.7%and 17.2%,respectively.