The Effects Of Dietary Metabolizable Energy And Protein Level On The Growth Performance,nutrients Utilization Rate And Digestive Enzyme Activities Of Frizzle Broilers

To study the effects of different levels of metabolizable energy(ME) and crude protein(CP) on the growth performance, slaughter performance, product quality,nutrients apparent metabolic rate, serum biochemical indexes and enzyme activities of intestinal digesta of 0~10 weeks frizzle broilers. The experiments utilized a 3x3 factorial complete randomized design. 360 healthy 1-day-old frizzle broilers were randomly divided into 9 experimental groups, there were 4 replicates with 10 broilers in each group. The broilers have two feeding stages(0~5 weeks and 6~10 weeks), ME and CP levels were 11.05MJ/kg, 12.10MJ/kg,13.15MJ/kg and 19.00%, 20.50%, 22.00% for 0~5weeks stage, 11.70MJ/kg, 12.75MJ/kg, 13.80MJ/kg and 17.50%, 18.55%, 19.60%for 6~10 weeks stage. The results show:(1) 0-5w, ADG in the same metabolizable energy level group has no significant different(P>0.05), ADG increase accordingly with the increase of energy. 13.15MJ/kg group is significantly higher than that of 11.05MJ/kg(P<0.05). Average daily feed intake(ADFI) differ significantly(P<0.05)and that of group 9 is the highest(ME13.15MJ/kg,CP22.00%). F/G differ significantly among groups( P<0.05) and that of group 5(ME12.10MJ/kg,CP20.50%)is the lowest one. ME and CP have no significantly affect on whole net carcass rate, half net carcass rate and slaughter rate(P>0.05). Level of CP can increase the breast muscle rate and leg muscle rate and the effect can be negative when CP level is too high. The difference of abdomen fat rate was significant(P<0.05)among groups and the lowest is in group 5(ME12.10MJ/kg,CP20.50%). The apparent utilization rate increases with the increase of energy and crude protein increasing. Therehave no significant effects on apparent utilization rate of crude ash, calcium and phosphorus(P>0.05), triglyceride, total protein(P>0.05). ME level has significant effects on total cholesterol and glucose(P<0.05). ME and CP have no significant effects on the activities of amylase and lipase(P>0.05). The trypsin activity is highest in group 5(ME12.10MJ/kg,CP20.50%).(2) 6~10w, ME and CP have significant effects on ADG and ADFI(P<0.05)and that of group 9 is the highest. F/G and abdominal fat rate of group 5 is the lowest.The breast muscle rate and leg muscle rate of group 9(ME13.80MJ/kg,CP19.60%)is the highest. The utilization rate of feed crude protein is higer in high-energy( ME:13.80MJ/kg)group and mid-energy group(ME:12.75 MJ/kg)than that of low-energy group.Utilization rate of crude fat can increase by increasing of ME. ME and CP have no significant effects on triglyceride, total cholesterol content, amylase and lipase activity(P>0.05). High-energy group(ME 13.80MJ/ kg)has the highest glucose level and group1,4,7(low protein groups) have the lowest uric acid and total protein levels.. Trypsin activity of group 5(ME12.75MJ/kg,CP18.55%)is the highest and that of group 2 is the lowest.All above, group 5(mid-energy mid-protein group) feed can increase the ADG,decrease F/G and abdominal fat rate, increase the utilization rate of crude fat and crude protein and trypsin activity. Ahe optimum levels of metabolizable energy and crude protein of fizzle broilers are:0~5w:12.10MJ/kg,20.50%;6~10w:12.75MJ/kg,18.55%.