本研究使用禽用开放回流式呼吸测热装置开展能量代谢试验，在相同饲养环境及饲粮条件下，探究不同品种蛋鸡饲粮净能转化效率的差异。试验共选用产蛋高峰期吉林芦花鸡和海兰褐鸡各60只，采用2×2析因设计，在同一鸡舍内，采用相同的玉米-豆粕型试验饲粮进行饲喂。试验预试期7 d，正试期58 d。正试期的第20天和第40天在2组试验鸡中分别选择9只鸡，称重后随机放入呼吸测热装置的6个代谢室内，每3个代谢室测试1个品种，每个代谢室内3只，连续测定2次。代谢室内测定气体交换和排泄物共9 d，其中适应期3 d、呼吸测热3 d、绝食测热3 d，呼吸测热的同时进行消化代谢试验。结果表明：在体重和采食量差异不显著（P>0.05）的情况下，吉林芦花鸡的产蛋率和平均蛋重显著低于海兰褐鸡（P<0.05）；吉林芦花鸡的表观代谢能、采食产热量和绝食产热量均显著高于海兰褐鸡（P<0.05），这导致了吉林芦花鸡的沉积能、表观代谢能转化为净能的效率（净能/表观代谢能）显著低于海兰褐鸡（P<0.05），净能/表观代谢能值分别为：海兰褐鸡72.21%和71.13%，吉林芦花鸡68.54%和66.31%。结果提示，在同一饲粮营养水平及环境条件下，由于芦花鸡较高的体产热导致了净能转化效率显著低于海兰褐鸡。

In this study, an open-circuit calorimeter for poultry was used to carry out an energy metabolism experiment to investigate the net energy conversion efficiency of different layer breeds under the same feeding environment and the same diets. Every 60 Hy-Line Brown and Jilin-Luhua chickens at laying peak were selected and fed an identical corn-soybean meal diet in the same henhouse with a 2×2 factorial design. Formal experiment period was 58 days after 7-day advanced experiment period. Every 9 birds from each group were selected respectively on the day 20 and day 40 of the formal experiment period, and after being weighed, they were randomly placed into 6 individual respiration chambers with 3 birds per chamber (a kind of bird was tested by three chambers, and continuous measurement for twice) to measure the value via gaseous exchange and total excreta collection for 9 days, including 3 days of dietary adaptation period, 3 days of respiratory calorimetry and 3 days of fasting heat production; meanwhile the digestion metabolism test was simultaneous with the respiratory calorimetry. The results showed that the laying rate and average egg weight of Jilin-Luhua chickens were significantly lower than those of Hy-Line Brown chickens (P<0.05) in the case of body weight and feed intake difference between them was not significant (P>0.05). The apparent metabolizable energy, heat production of feeding and fasting heat production of Jilin-Luhua chickens were significantly higher than those of Hy-Line Brown chickens (P<0.05), which made the retained energy and apparent metabolic energy conversion to net energy efficiency (apparent metabolic energy to net energy ratio) were significantly decreased (P<0.05). Apparent metabolic energy to net energy ratios were as follows:Hy-Line Brown chickens were 72.21% and 71.13%, and Jilin-Luhua chickens were 68.54% and 66.31%, respectively. In conclusion, as more heat production, the net energy conversion efficiency of Jilin Luhua chickens is significantly lower than Hy-Line Brown chickens at the same diets and environmental conditions.