Measurement On Net Energy Value Of Corn And Soybean Meal And Application Of Net Energy System For Laying Hens

This study includes two experiments; the first one was to measurement on net energy value of corn and soybean meal for laying hens. The second experiment was to investigate effects of dietary net energy(NE) and metabolizable energy(ME) levels on performance in laying hens.In Exp.1, The study was conducted to establish a reasonable method for determining NE value of corn and soybean meal by using digestion-metabolism experiment and measurement heat production. Crossover study design was carried out. A total of 96 65-week-old White Leghorn hens were allotted into 2 groups with the principle of equal body weight, and each group was raised in respiration chamber for digestion-metabolism experiment and measurement heat production. Net energy value of corn and soybean meal for laying hens was cultivated by dispersion method. Apparent metabolizable energy(AME) value of corn and soybean in laying hens was 14.70 and 10.61 MJ/kg, respectively. Laying hens heat production (HP) of corn-soybean diet and corn diet was (485.21±33.31) and (483.03±34.06)kJ/(kg·d), respectively. Fasting heat production(FHP)in laying hens with average body weight of 1.44 kg was 390.29 kJ/(kg·d). NE value of corn and soybean for laying hens was 11.97 and 8.15 MJ/kg, respectively. Conversion efficiency of AME to NE of corn and soybean was 81 % and 77 %, respectively.In Exp.2, This experiment was conducted to study the effect of different net energy(NE) and metabolizable energy(ME) levels on performance, to give reference for practice production. Two hundred and seventy 30-week-old laying hens were randomly divided into 5 groups with 6 replicates each and 9 birds in each replicates. 5 groups were fed with 5 diets containing crude protein(CP) 14.77 % and NE(ME)(groupI～Ⅴ)(8.3(10.3),8.4(10.5),8.5(10.6),8.7(10.8),8.8(10.9)MJ/kg, respectively). The experiment lasted 30 d. The results showed Egg weight, egg production and feed to egg ratio were not influenced by Energy levels(P>0.05). GroupI～Ⅴaverage daily feed intake were followed: 109.59 g, 110.10 g, 109.86 g, 104.50 g, 105.74 g , respectively. GroupⅣis significantly different from groupI～III (P<0.05).Compared with groupI～III, groupⅤhad significant difference(P<0.05).There were no significant difference between groupⅣandⅤ(P>0.05), groupI～III had no significant difference(P>0.05). Therefore, net energy system can be used in formulated diets for laying hens to reduce in dietary energy levels, and better improve the economic benefits.