基于密闭式呼吸测热法测定肉鸡饲粮能量流向及可加性研究OA

The objective of this experiment was to investigate the energy flow of diets and its additivity in broilers using closed respiratory calorimetry systems,providing a reference for the accurate evaluation of effective energy in feeds for broilers.A single-factor completely randomized design was used,consisting of four dietary treatments:basal diet,corn diet,soybean meal diet and corn-soybean meal diet.A total of sixty 21-day-old Arbor Acres Plus male broilers,with similar body weight(BW,1 020±15 g)were selected and randomly divided into 20 groups,with 3 broilers per group,and allocated to 20 respiratory chambers.Each dietary treatment was assigned to 5 respiratory chambers.The energy partioning and their additivity in the diets were determined using the indirect calorimetry method.The results showed that:1)The coefficient of variation for O2 consumption,CO2 production and respiratory quotient of broilers measured by the closed respiratory calorimetry system ranged from 1.51％to 3.96％.2)The CO2 production per kg metabolic BW and respiratory quotient in broilers decreased with increasing dietary protein oxidation.The net energy(NE),ratios of NE to gross energy(NE/GE),NE to apparent metabolizable energy(NE/AME)and retained energy to AME(RE/AME)decreased with increasing dietary protein oxidation,but increased with increasing metabolizable protein(MCP)(P＜0.05).The ratios of total heat production to AME(THP/AME)and heat increment to AME(HI/AME)increased with increasing dietary protein oxidation and decreased with increasing MCP(P＜0.05).The R2 for regression of average daily gain on NE or RE intake was higher than that on AME intake.3)In the additivity test of energy flow in corn and soybean meal,the determined values of AME,nitrogen-corrected AME(AMEn),NE and HI were not significantly different from the weighted calculated values,and the differences were all less than 0.19 MJJ·kg-1.There were significant differences between the determined and the weighted calculated values of THP,RE,NE as retained protein(NEp)and NE as retained fat(NEf)(P＜0.05).These results indicate that the closed-circuit respiratory calorimetry method provides good precision in measuring O2 consumption,CO2 production and respiratory quotient in broilers.The data of energy flow is consistent with the basic principles of animal nutrition,and NE or RE is more indicative of the effective energy value of feeds.The AME,NE and HI are additive,while THP,RE,NEp and NEf are not additive.