Kyriazakis I, Dotas D, Emmans G C
Genetics and Behavioural Sciences Department, SAC Edinburgh.
Br J Nutr. 1994 Jun;71(6):849-59. doi: 10.1079/bjn19940191.
The objective of the present experiment was to test whether the relationship between feed composition and the efficiency of protein utilization in pigs was different between two very different breeds. Forty-eight entire male pigs, half Large White x Landrace (LW x) and half Chinese Meishan (CM), were assigned at 13 kg live weight either to an initial slaughter group or to one of six feeding treatments for 6 weeks. The two feeds used were starch, with 12.52 MJ metabolizable energy (ME) and 0 kg digestible crude protein (DCP)/kg, and a high-protein feed, with 11.95 MJ ME and 0.362 kg DCP/kg. In the first week the LW x pigs were given 400 g high-protein feed/d with 0, 100, 200 or 300 g starch/d, or 200 g high-protein feed/d with 400 or 500 g starch/d. The six diets had ME:DCP ratios of between 33 and 119 MJ/kg. The diet compositions were held constant within each of the six treatments but the allowances were increased weekly on time-based linear scales to be 2.25 as great in week six as in week one. The allowances for the CM pigs were 0.75 of those for the LW x. The calculated efficiency of protein utilization, ep, was found to be directly proportional, up to a maximum value, to the ME:DCP ratio of the diet for both breeds, as found previously for LW x male and female pigs. The overall constant of proportionality was ep = 0.0108 (SE 0.00024) ME:DCP, the value of which did not differ significantly between the two breeds. The maximum observed ep values were 0.710 (SE 0.014) and 0.824 (SE 0.016) for the LW x and CM pigs respectively. It is likely that the lower maximum value for the LW x pigs was an experimental artefact due to increased feed spillage by these pigs on the two highest starch allowances used. In previous experiments the maximum value of ep was found to be 0.813 for LW x pigs, a value similar to that found here for the CM pigs. The results are consistent with the view that the two very different pig breeds have the same net efficiency in using protein and use the same rules for partitioning a scarce resource such as energy.
本实验的目的是检验在两个差异极大的猪品种中，饲料组成与猪蛋白质利用效率之间的关系是否不同。48头雄性仔猪，一半是大白猪×长白猪（LW×），一半是中国梅山猪（CM），在体重13千克时，被分配到一个初始屠宰组或六个饲养处理组之一，为期6周。使用的两种饲料分别是：淀粉，代谢能（ME）为12.52兆焦/千克，可消化粗蛋白（DCP）为0千克/千克；高蛋白饲料，ME为11.95兆焦/千克，DCP为0.362千克/千克。在第一周，LW×猪每天分别给予400克高蛋白饲料加0、100、200或300克淀粉，或200克高蛋白饲料加400或500克淀粉。这六种日粮的ME:DCP比值在33至119兆焦/千克之间。六种处理中每种处理的日粮组成保持不变，但供应量按基于时间的线性比例每周增加，到第六周时是第一周的2.25倍。CM猪的供应量是LW×猪的0.75倍。结果发现，对于两个品种而言，计算得出的蛋白质利用效率（ep）与日粮的ME:DCP比值成正比，直至达到最大值，这与之前对LW×公猪和母猪的研究结果一致。总体比例常数为ep = 0.0108（标准误0.00024）ME:DCP，两个品种之间该值无显著差异。LW×猪和CM猪观察到的最大ep值分别为0.710（标准误0.014）和0.824（标准误0.016）。LW×猪较低的最大值可能是实验假象，因为在使用的两种最高淀粉供应量下，这些猪的饲料浪费增加。在之前的实验中，LW×猪的ep最大值为0.813，与这里CM猪的值相似。这些结果与以下观点一致：这两个差异极大的猪品种在蛋白质利用方面具有相同的净效率，并且在分配能量等稀缺资源时遵循相同的规则。
