| This experiment was investigated to evaluate available energy of 10 kinds of corn from different sources, then compare the results of different methods. Standardized laboratory analysis methods was used to analyze the physical and chemical indicators of corn samples, include crude protein, crude fat, crude ash, neutral detergent fiber, acid detergent fiber. Then use these available energy and physical and chemical indicators to path analysis and stepwise regression equation was established.Experiment 1 : Available energy of corn for AA broiler determined by Substitution Method and Direct Force-Feeding MethodThis experiment was investigated to evaluate available energy of corn for Arbor Acres(AA) broilers. The experiment includes two determination method: substitution method and direct force-feeding method. Substitution method selects seven hundred and four 28-day-old healthy female and male AA broiler, randomly assigned to 11 groups(each group 8 repeat, each repeat 8 broilers): The control group was fed basal diet, test group was fed 10 different kinds of corn-substitute diet(the substitute proportion was 40%), phase 7d trial. Direct force-feeding method selects sixty healthy adult breeder broilers as test animals, randomly assigned to 5 groups(each group 6 repeat, each repeat 2 broilers): 10 kinds of corn were force feeding the broilers in each groups. Follow the 48 h fasting-force feeding-48 h excretion collection operation process(GB/T26437-2010). The results showed as follows: 1) Available energy measured by direct force-feeding were significantly lower than those of total collect method,indicator method and ileal digesta method(P<0.05); The available energy measured by total collect method, indicator method and ileal digesta method have no significant difference(P>0.05). 2) Indicator method and total collect method, indicator method and ileal digesta method has significant correlation at 0.01 level(Two-tailed), the correlation coefficients were 0.777 and 0.952; total collect method and ileal digesta method has significant correlation at 0.05 level(Two-tailed), the IV correlation coefficients were 0.683. It is concluded that the available energy evaluated by direct force-feeding were significantly lower than substitution method, the available energy evaluated by total collect method, indicator method and ileal digesta method which were based on substitution method had no significant difference. The available energy evaluated by indicator method and ileal digesta method, indicator method and total collect method, total collect method and ileal digesta method has significant correlation(the correlation coefficients were 0.952, 0.777 and 0.683), direct force-feeding method has no significant correlation when compared with other three kinds method.Experiment 2 : The establishment of corn available energy prediction modelAccording to the available energy values of corn from experiment 1, the direct and indirect effects of physical and chemical indexes of corn on available energy were analyzed with SPSS software, and the optimum regression equation were established subsequently. It was concluded that: Indicator method:(1) The direct effect of crude protein(CP) on AME was the largest, path coefficient was-1.386, next was crude ash(CA), which was 0.761, and the smallest was neutral detergent fiber(NDF), path coefficient was-0.174; The indirect effect of crude ash(CA) on AME was the largest, path coefficient was-1.191, next was crude protein(CP), which was 0.672, and the smallest was neutral detergent fiber(NDF), path coefficient was-0.193.(2)The important predictors were CP, and the optimun regression equation was: AME=16.959-0.409CP(R2=0.509, P<0.05). Total collect method:(1) The direct effect of ether extract(EE) on AME was the largest, path coefficient was-0.445, next was crude protein(CP), which was-0.415, and the smallest was acid detergent fiber(ADF), path coefficient was-0.086; The indirect effect of crude ash(CA) on AME was the largest, path coefficient was-0.497, next was neutral detergent fiber(NDF), which was-0.313, and the smallest was gross energy(GE), path coefficient was-0.059.(2)The important predictors were CA, and the optimun regression equation was: AME= 14.958-0.409CA(R2 = 0.408, P<0.05). Ileal digesta method:(1) The direct effect of crude protein(CP) on IDE was the largest, path coefficient was-1.487, next was crude ash(CA), which was 0.975, and the smallest was ether extract(EE), path coefficient was-0.225; The indirect effect of crude ash(CA) on IDE was the largest, path coefficient was-1.466, next was crude protein(CP), which was 0.699, and the smallest was neutral detergent fiber(NDF), path coefficient was 0.015.(2)The important predictors were CP, and the optimun regression equation was: IDE= 17.406-0.458CP(R2 = 0.621, P<0.01). |
PDF Full Text Request