Kyriazakis I, Emmans G C
Genetics and Behavioural Sciences Department, SAC, Edinburgh.
Br J Nutr. 1995 Aug;74(2):183-95. doi: 10.1079/bjn19950122.
An experiment was designed to test the prediction that two genetically-very-different kinds of pigs would retain the same amounts of protein in their bodies when given the same allowances of the same feed for the same period of time, when these allowances were limiting for both. An allowance of 33.957 kg of a feed with 12.76 MJ metabolizable energy (ME) and 189 g crude protein (N x 6.25)/kg feed was given to Large White x Landrace (LW x) and Chinese Meishan (CM) female pigs over three different periods of time: (1) ad lib. (AL) with the time taken by individual pigs to consume the allowance being a variable, (2) over a period of 7 weeks (H) and (3) over a period of 9 weeks (L). In addition, in a fourth treatment, pigs of both breeds received the same allowance but supplemented with starch also over a period of 7 weeks (HS). The performance of the pigs on treatment AL was affected by pig breed, with CM pigs gaining protein at a slower, and lipid at a faster, rate than LW x pigs. On treatments L, H and HS the average amounts of protein retained were 2.693 and 2.655 kg for the LW x (n 15) and CM (n 15) pigs respectively (SED 0.106 kg). There was a statistical indication that the LW x pigs may have been more efficient on L, and less efficient on HS, than the CM pigs but we have been unable to propose any biological reason for such an effect, if it was in fact a real one. Thus, the efficiency with which ideal protein was utilized was close to being constant, and apparently at its maximum, for the two breeds. However, although CM pigs had the same protein gain, and the same live weights, on the same feed allowances as the LW x pigs, they gained significantly more lipid. This was attributed in part to their digesting their feed better and in part to their having a lower energy requirement for maintenance through a lower level of physical activity. Given that these two very different kinds of pigs use limiting protein with the same efficiency, it is suggested that it is safe to make the assumption in models of pig growth that the material efficiency of using limiting protein is constant across genotypes of pig.
当给两种基因差异很大的猪提供相同量的同一种饲料，且供应时间相同，同时这些供应量对两种猪都处于限制水平时，它们体内保留的蛋白质量相同。给大白猪×长白猪（LW×）和中国梅山猪（CM）的母猪提供33.957千克含有12.76兆焦代谢能（ME）和189克粗蛋白（N×6.25）/千克饲料的饲料，时间分为三个不同阶段：（1）自由采食（AL），每头猪消耗该供应量饲料的时间为变量；（2）为期7周（H）；（3）为期9周（L）。此外，在第四种处理方式中，两个品种的猪都接受相同的供应量，但在7周内还添加了淀粉（HS）。接受AL处理的猪的生长性能受品种影响，CM猪积累蛋白质的速度比LW×猪慢，积累脂肪的速度比LW×猪快。在L、H和HS处理方式下，LW×猪（n = 15）和CM猪（n = 15）保留的平均蛋白质量分别为2.693千克和2.655千克（标准误0.106千克）。有统计迹象表明，LW×猪在L处理方式下可能比CM猪更高效，在HS处理方式下效率更低，但如果这确实是真实的差异，我们无法提出任何生物学原因来解释这种效应。因此，对于这两个品种来说，理想蛋白质的利用效率接近恒定，且显然处于最高水平。然而，尽管CM猪在相同的饲料供应量下与LW×猪有相同的蛋白质增加量和相同的体重，但它们积累的脂肪显著更多。这部分归因于它们对饲料的消化更好，部分归因于它们通过较低水平的体力活动维持所需的能量更低。鉴于这两种差异很大的猪利用限制性蛋白质的效率相同，建议在猪生长模型中可以安全地假设，使用限制性蛋白质的物质效率在不同基因型的猪中是恒定的。
