The Effect Of Dietary Crude Protein And Energy Level On Performance, Nutrient Utilization And Related Genes In Broiler

The experiment was conducted to evaluate the effect of crude protein and energy level of diets on performance, nutrient digestion and related genes in broilers. A total three hundred and twenty 21-day-old broilers were randomly allocated to 4 treatments,each treatment with eight repeats and ten birds per cage,and were fed the four diets with two levels of crude protein(CP)(16% and 18%) and energy(12.34 MJ/kg and13.17 MJ/kg). The diets were fed to birds for 21 days. The results shown:(1) The crude protein and energy level of diets had significant interaction on BWG and F/G(P < 0.05).BWG of 18% CP group was significantly higher than that of16% CP, but reverse case for the F/G(P<0.05). Diet with high energy was significantly higher at BWG than that of low energy diet, and reverse case for the F/G(P< 0.05).(2) The DM, CP and IDE of 16% CP group were higher than that of 18% CP group(p=0.067; p=0.087; p=0.076), and DM utilization of it was significantly higher than that of 18% CP group(P< 0.05), however, the N utilization was reduced by4.93%(P< 0.05). Compared with 16% CP, AME and AMEn of 18% CP group were significantly improved(P<0.05). AME of diet with high energy level was significantly higher than that of diet with low energy(P<0.05).(3) With the increasing of CP and energy level of diets, the expression of nutrient transporters m RNA were reduced at different level. Expression of bo,+AT and CAT2 m RNA in duodenum of 16% CP group were significantly higher than that of 18% CP group(P<0.05). Expression of y+LAT2 and GLUT5 m RNA in ileum and y+LAT2 in jejunum of 16% CP group were significantly higher than that of 18% CP group(P<0.05). Compared with high energy diet, expression of Pe PT1 、 SGLT1 �'� y+LAT2m RNA in ileum and jejunum of low energy diet were significantly increased(P<0.05).In a word, the growth performance and feed conversion rate were improved as the CP, AME level of diet increased from 16%, 12.34 MJ/kg to 18%, 13.17 KJ/kg.The diet with 12.34 MJ/kg AME had higher expression of SGLT1 in jejunum and ileum and GLUT5 in duodenum, and the 18% CP diet had higher expression of PePT1 in jejunum and Bo AT in jejunum and ileum, but the expression of y+LAT2 in jejunum and ileum of 16% CP diet were improved.