Study On Suitable Protein Levels Of Frizzle Femalebroilers Based On Environment-friendly

In this experiment,the effects of different dietary protein levels on growth performance,nutrient excretion and intestinal histology of Frizzle female broilers were studied in order to determine the environment-friendly dietary protein requirement of Frizzle female broilers.The experiment was designed by a single factor completely randomized design.200 chickens of the same age,which were similar in hatching,health and weight,were randomly divided into 5 groups,with 4 replications and 10 chickens per replicate.The 5 groups were fed with five protein-level diets(15%,17%,19%,21%,and 23% respectively),ME was 12.40 MJ/kg,and all other nutrient contents were consistent,the experiment lasted for 12 w.The results showed the following:1.Growth performance: With the increase of dietary protein level,weight gain,ADG and ADFI of 1-4 w Frizzle female broilers increased significantly(P<0.05),F/G decreased significantly(P<0.05);at 5-8 w Frizzle female broilers ADG increased significantly(P<0.05),while at 17% CP level dietray F/G was significantly lower than 15% CP level(P<0.05);the best growth performance was 9-12 w at 17% CP level.2.Relative nutrient excretion and correlation and nutrient utilization rate: The discharge of DM,GE,and P of 17% CP dietary level were significantly lower than those of others CP level of 1-4 w Frizzle female broilers(P<0.05),the discharge of CP were significantly lower than those of 21% and 23% CP level.The discharge of nutrients of 15% and 17% CP dietary levels were lower than those of other CP levels of 5-8 w and 1-8 w Frizzle female broilers(P<0.05).With the increase of dietary CP level,the discharge of nutrienst of 9-12 w and 1-12 w both increased and then decreased,and the lowest CP levels were 15% and 17%.The correlation of 17% CP level between the relative ADFI and the discharge of Ash was highly significantly positive(P<0.01);the correlation of 23% CP level between the relative ADFI and the discharge of CP was significantly positive(P<0.05),and that of EE and DM was significantly negative(P<0.05).The utilization of nutrients at 15% and 17% CP level was better during the whole feeding period.3.Intestinal enzyme activity: With the increase in protein level,the protease and the lipase in 21% CP level were the best in 4w Frizzle female broilers;the protease activity of 8w Frizzle female broilers significantly decreased,and the amylase activity in 17% CP level were significantly higher than other CP level(P<0.05),the lipase activity was higher than that of 19% CP level(P<0.05);the lipase activity at 19% and 21% CP level was higher than others CP level(P<0.05).4.Intestinal tissue structure: With the increase of protein level,the intestinal villus height significantly improved(P<0.05).The intestinal development of 21% and 23% CP level of 4 w Frizzle female broilers was the best;The duodenum and ileum villus height of the 21% CP level of 8 w Frizzle female broilers significantly increased(P<0.05),the duodenum V/C was significantly reduced(P<0.05),and jejunum villus height was higher than 17% CP level(P<0.05).The intestinal tract of Frizzle female broilers with 12 w CP level was well developed.Based on growth performance and the CP discharge,under the conditions of this test,the optimal CP level based on environmental protection for frizzle female broilers was 1-4 w: 19%;5-8 w: 17%;9-12 w: 17%.