Study On Protein Metabolism And Requirement Of Luhua Chickens In Growing Period

This experiment systematically studied protein requirement of Luhua Chicken duri ng growing period and formulated protein feeding standard under different crude protei n levels.A total of six hundreds healthy one-day-old Luhua Chicken（half female and half male）were selected as experimental animal.The experimental periods were divided int o 0 to 6 weeks,7 to 14 weeks and 15 to 20 weeks three periods.0 to 6 wk:Femal e and male were mixed,six hundreds were randomly divided into five treatments with six replicates of twenty birds each;7 to 14 weeks and 15 to 20 weeks:female and male were separated,each gender three hundreds birds were randomly divided into fi ve treatments with six replicates of ten birds each.Each period owned five different CP levels dietary with same metabolizable energy level,the CP levels were defined as CP 1,CP 2,CP 3,CP 4 and CP 5 respectively.0 to 6 weeks:CP levels were resp ectively 17.5%,18.0%,18.5%,19.0%and 19.5%,ME level was 2900 kcal/kg;7 to 14 weeks:CP levels were respectively 15.0%,15.5%,16.0%,16.5%and 17.0%,ME le vel was 2850 kcal/kg;15 to 20 weeks:CP levels were respectively 13.5%,14.0%,14.5%,15.0%and 15.5%,ME level was 2800 kcal/kg.Metabolism experiment was cond ucted in the middle of 7 to 14 weeks by all faeces collected method to obtain nutrien ts and energy utilization.Slaughter experiments were conducted at 1d,end of 6 weeks,end of 14 weeks and end of 20 weeks,1d,end of 6 weeks and end of 14 weeks we re to obtain body composition,and end of 6 weeks,end of 14 weeks and end of 20weeks were to obtain slaughter performance.The results showed as follows:Production performance:0 to 6 weeks:Average daily feed intake、average dail y gain and final body weight were significantly affected by different CP levels（P<0.05）.7 to 14 weeks:All production performance items were significantly affected by d ifferent gender（P<0.01）,the average daily feed intake and feed to gain were also s ignificantly affected by different CP levels（P<0.05）.15 to 20 weeks:Average dai ly feed intake and final body weight were significantly affected by different gender（P<0.01）,average daily gain and final weight were also significantly affected by differe nt CP levels（P<0.05）,the interaction effect between gender and CP level had a s ignificant influence on feed to gain（P<0.05）.Change rule of production performance:As the week of age increased,feed in take and body weight increased.daily gain during 7 to 14 week was higher than 0 to6 week and 15 to 20 week.Nutrient and energy utilization:The apparent metabolic rate of ether extract and carbohydrate were significantly affected by different gender（P<0.05）,the apparent m etabolic rate of crude protein and carbohydrate and apparent metabolizable energy we re significantly affected by different CP levels（P<0.05）.Body composition:End of 6 weeks:body dry matter content,body crude protein content and body carbohydrate content were significantly affected by different gender（P<0.05）,all body composition items were not significantly affected by different CP levels（P>0.05）.End of 14 weeks:all body composition items were significan tly affected by different gender except for body carbohydrate content（P<0.01）,all body composition items were not significantly affected by different CP levels（P>0.05）.Slaughter performance:slaughter performance at the end of each stage were sig nificantly affected by different gender（P<0.01）,slaughter performance at the end of each stage were not significantly affected by different CP levels（P>0.05）.Protein requirement:The protein requirement factorial models of Luhua Chicken during growing period showed as follows:0～6 wk:Female and male mixed:CPR=1.59 BW^0.75+0.6177 ADGNCPR=1.08 BW^0.75+0.1967 ADG7～14 wk:Female:CPR=1.58 BW^0.75+0.6247 ADGNCPR=1.10 BW^0.75+0.1881 ADGMale:CPR=1.52 BW^0.75+0.4959 ADGNCPR=1.06 BW^0.75+0.1498 ADG15～20 wk:Female:CPR=1.48 BW^0.75+0.8305 ADG NCPR=1.07 BW^0.75+0.2305 ADGMale:CPR=1.52 BW^0.75+0.8495 ADGNCPR=1.08 BW^0.75+0.2486 ADGIn the formula:CPR:Represents the daily crude protein requirement of each chicken,the unit is g/d/bird.NCPR:Represents the daily net protein requirement of each chicken,the unit is g/d/bird.BW^0.75:Indicates the metabolic weight,the unit is kg.ADG:Indicates the daily weight gain,the unit is g.