Determination Method Of Feed Net Energy And Its Application For Broilers

In the present study,the determination method of net energy（NE）of ingredients,and the effect of process technology on NE values of ingredients for broilers were investigated.The NE values of common ingredients were determined for broilers,and the effect of formulation by using NE on the growth profermance of broilers was investigated.In experiment 1,the NE_m of broilers was determined using regression models by the respiratory calorimetry method（RCM）or the comparative slaughter method（CSM）.A 2×4factorial arrangement of treatments including the evaluation method（RCM or CSM）and feed intake（25,50,75,or 100%of ad libitum recommended）was employed in this experiment.One hundred and ninety-two male Arbor Acre（AA）broilers aged 14 d were assigned into 8 treatments with 4 birds per replicate and 6 replicates in each feed intake treatment.Twenty birds aged 15 d were used as the initial slaughter group.The evaluation method had no effect on heat production of broilers.The NE_m was 448 kJ/kg BW^0.75·d^-1 for broilers age 1 to 3 weeks old.In experiment 2,this experiment was investigated to study the effects of body weight on total heat production（THP）and fasting heat production（FHP）of broilers at 4 to 7 weeks of age by using the respiratory calorimetry method.A total of 48 male AA broilers at 4 to 7 weeks of age were selected.At every week,one group of 12 broilers was randomly sent into 6 same respiratory chambers for energy metabolism test.A fasting of 48 h was suitable for broilers’net energy measurement at 4 to 7 weeks of age.The body weight had a significant effect on THPand FHP for AA broilers at 4 to 7 weeks of age.The NE_m was 465 kJ/kg BW^0.74·d^-1 for broilers age 4 to 7weeks old.In experiment 3,the substitution and direct methods were used to determine the NE value of corn in broilers.Seventy-two male AA broilers aged 15 d were assigned into 3 experimental diets with 4 birds per replicate and 6 replicates.The substitution and direct methods had no effect on NE values of corn.The substitution method was recommended to determine the NE values of ingredients.In experiment 4,the NE values of four corn varieties including two normal corn varieties（Zheng Dan 958 and Xian Yu 335）,waxy corn and sweet corn were determined for broiler breeding cocks using the respiratory calorimetry method.Thirty AA broiler breeding cocks were assigned into 5 experimental diets with 1 birds per replicate and 6 replicates.The NE value of sweet corn diet were higher（P<0.05）than other 3 corn samples.The respective NE values were 11.22,11.31,11.20 and 11.74 MJ/kg for Zheng Dan 958,Xian Yu 335,waxy corn,and sweet corn.In experiment 5,the effect of basal diet type and process technology on NE value of soybean meal for broilers were investigated.One hundred forty-four male AA broilers aged 15 d were assigned into 6 experimental diets with 4 birds per replicate and 6 replicates.The basal diet type and fermentation treatment had no effect on the NE values of soybean meal.In experiment 6,the effect of dehulled process technology on the NE values of soybean meal were determined for broiler breeding cocks using the respiratory calorimetry method.Eighteen AA broiler breeding cocks were assigned into 3 experimental diets with 1 birds per replicate and 6replicates.No differences in AME and NE values were found between regular soybean meal and dehulled soybean meal.In experiment 7,the substitution method was used to determine the NE value of soybean meal,cottonseed meal,rapeseed meal and DDGS in broilers.One hundred twenty male AA broilers aged 15 d were assigned into 1 basal diet and 4 test diets with 4 birds per replicate and 6replicates.The NE values of soybean meal,cottonseed meal,rapeseed meal and DDGS determined by the substitution method were 6.99,4.71,4.79 and 6.28 MJ/kg.In experiment 8,the effect of diets with different NE values on the growth performance of broilers were investigated.Four hundred day-old male broilers were assigned into 5 diets with 10birds per replicate and 8 replicates in each diet.The superiority of net energy may be reflected in accurate evaluation of the energy requirement for broilers,and applying the unconventional ingredients for formulation.