Techna, BP10, F-44220 Couëron, France.
Animal. 2011 Feb;5(2):202-10. doi: 10.1017/S1751731110001709.
Determining energy utilization in growing animals enables to adjust the nutritional constraints to nutrient requirements while maximizing the ratio between lean retention and fat retention to improve feed efficiency. In turkey production, the important sexual dimorphism and differences between strains may contribute to differences in basal energy metabolism and the partitioning of energy retention between protein and lipid. The objective of this study was to determine the dynamics of energy utilization in males and females of a heavy strain of turkeys fed ad libitum from 1 to 23 weeks of age. Heat production (HP) was determined by indirect calorimetry and retained energy (RE) was calculated as the difference between metabolizable energy (ME) intake and HP. The RE as protein was determined by a nitrogen balance, while the remaining RE was assumed to be lipid. A modeling procedure allowed partitioning HP between fasting HP (FHP), activity-related HP and thermic effect of feeding. A multiple regression analysis was used to estimate the maintenance energy expenditure (ME(m)) and the energy efficiencies of protein and lipid retention (k(p) and k(f), respectively). Results were expressed either per day or per kg BW(0.75) per day. In comparison with females, males consumed more feed (440 v. 368 g/day), grew faster (163 v. 147 g/day) and retained more protein (38 v. 28 g/day) during the experimental period. Expressed per kg BW(0.75) per day, ME intake decreased linearly with increasing age and was not affected by gender. Similarly, RE as protein decreased with increasing age and tended to be greater in males than in females, whereas RE as lipid increased with increasing age and was lower in males than in females. In addition, HP decreased with increasing age and was greater in males than in females, because of greater activity-related HP and FHP (47% and 9% greater in males compared with females). The FHP averaged 417 kJ/(kg BW)(0.75) per day during the first 3 weeks of age and decreased to 317 and 277 kJ/(kg BW)(0.75) per day in males and females, respectively, from 20 weeks of age onwards. Similar to FHP, ME(m) was lower in females than in males ((586 to 12 × BW) and (586 to 5 × BW) kJ/(kg BW)(0.75) per day, respectively) and the k(p) and k(f) were estimated at 0.63 and 0.87, respectively. This study shows that the partitioning of RE and HP differs between genders in growing turkeys, which likely results in differences in nutrient requirements.
确定生长动物的能量利用情况，可在最大限度提高瘦肉和脂肪保留率与饲料效率之比的同时，调整营养限制以满足营养需求。在火鸡生产中，重要的性别二态性和品种间差异可能导致基础能量代谢和能量保留在蛋白质和脂质之间分配的差异。本研究旨在确定从 1 至 23 周龄自由采食的重型火鸡雄性和雌性的能量利用动态。通过间接测热法确定产热量（HP），并将可代谢能（ME）摄入量与 HP 之间的差值作为保留能（RE）。通过氮平衡确定蛋白质的保留能（RE 作为蛋白质），其余的保留能（RE 作为脂质）则假定为脂质。建模程序允许将 HP 在空腹 HP（FHP）、与活动相关的 HP 和饲料热效应之间进行分配。使用多元回归分析估计维持能量支出（ME(m)）和蛋白质与脂质保留效率（k(p)和 k(f)）。结果按每日或每千克 BW(0.75)·日表示。与雌性相比，雄性在试验期间的采食量更多（440 比 368 g/天）、生长速度更快（163 比 147 g/天）、蛋白质保留量更多（38 比 28 g/天）。按每千克 BW(0.75)·日表示，ME 摄入量随日龄的增加呈线性下降，不受性别影响。同样，RE 作为蛋白质随日龄的增加而减少，且雄性的 RE 作为蛋白质大于雌性，而 RE 作为脂质随日龄的增加而增加，且雄性的 RE 作为脂质小于雌性。此外，HP 随日龄的增加而减少，雄性大于雌性，这是因为与活动相关的 HP 和 FHP 更大（雄性比雌性分别高 47%和 9%）。在 3 周龄之前，FHP 平均为 417 kJ/（kg BW）(0.75)·日，从 20 周龄开始，雄性和雌性的 FHP 分别下降至 317 和 277 kJ/（kg BW）(0.75)·日。与 FHP 类似，雌性的 ME(m)小于雄性（分别为 586 至 12×BW 和 586 至 5×BW kJ/（kg BW）(0.75)·日），k(p)和 k(f)分别估计为 0.63 和 0.87。本研究表明，生长火鸡的能量保留和 HP 在性别间存在差异，这可能导致营养需求的差异。
