White H M, Richert B T, Schinckel A P, Burgess J R, Donkin S S, Latour M A
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
J Anim Sci. 2008 Aug;86(8):1789-98. doi: 10.2527/jas.2007-0801. Epub 2008 Mar 14.
Managing stressors is essential for optimizing pig growth performance. To determine the effects of temperature and space allocation on growth performance and carcass characteristics, pigs were housed within their thermoneutral zone, at 23.9 degrees C, or above their thermoneutral zone, at 32.2 degrees C, and were provided either 0.66 or 0.93 m(2)/pig for the final 35 d of the grow-finish period. Individual BW were recorded on d 1, 10, 20, and 30. At slaughter, carcass measurements and samples of backfat and belly fat were collected. Final BW was decreased (P < or = 0.05) from 113 to 103 kg for pigs housed at 32.2 degrees C. The ADG was reduced (P < 0.05) for pigs housed at 32.2 degrees C (0.89 vs. 0.54 kg/d), as was G:F (0.28 vs. 0.24). Housing at 0.66 m(2)/pig resulted in pigs that were lighter (P < or = 0.05), at 106 compared with 110 kg, as a result of decreased (P < or = 0.05) ADG (0.78 to 0.65 kg/d) and decreased (P < or = 0.05) G:F (0.275 to 0.255) compared with pigs housed at 0.93 m(2)/pig. Pigs housed at a greater spatial allocation had elevated (P < or = 0.05) ADFI. The interaction of housing at 32.2 degrees C and decreasing spatial allocation increased (P < or = 0.05) the adipose iodine value from 66.8 to 70.4, decreased (P < or = 0.05) the saturated:unsaturated fatty acids ratio from 0.59 to 0.56, and increased (P < or = 0.05) the n-6:n-3 from 23.56 to 25.27. Decreased spatial allocation resulted in decreased (P < or = 0.05) belly weights. Although increased temperature did not affect belly weight, the 32.2 degrees C pigs had decreased (P < or = 0.05) raw and cooked slice weights, increased (P < or = 0.05) percentage lean of bacon, increased (P < or = 0.05) lean:fat ratio of bacon slices, increased (P < or = 0.05) raw slice scores, and increased (P < or = 0.05) quantity of collagen in belly fat. Some of these changes may have resulted from changes in lipid metabolism. Increasing spatial allocation in the 32.2 degrees C pigs decreased fatty acid synthase (P = 0.03) and stearoyl-CoA desaturase- 1 (P = 0.08) mRNA expression in adipose tissue. The results from this study demonstrated decreased growth, carcass lipid quality, and bacon quality in pigs housed at temperatures above the thermoneutral zone; however, increasing the spatial allocation for housing may be a means to ameliorate the negative effects of temperature stress.
管理应激源对于优化猪的生长性能至关重要。为了确定温度和空间分配对生长性能和胴体特性的影响，将猪饲养在其热中性区（23.9摄氏度）或高于其热中性区（32.2摄氏度），并在生长育肥期的最后35天为每头猪提供0.66平方米或0.93平方米的空间。在第1、10、20和30天记录个体体重。屠宰时，收集胴体测量数据以及背膘和腹脂样本。饲养在32.2摄氏度的猪的末体重从113千克降至103千克（P≤0.05）。饲养在32.2摄氏度的猪的平均日增重降低（P<0.05）（0.89千克/天对0.54千克/天），料重比也降低（0.28对0.24）。每头猪饲养空间为0.66平方米时，猪的体重较轻（P≤0.05），为106千克，而每头猪饲养空间为0.93平方米时猪的体重为110千克，这是由于与每头猪饲养空间为0.93平方米的猪相比，平均日增重降低（P≤0.05）（从0.78千克/天降至0.65千克/天）以及料重比降低（P≤0.05）（从0.275降至0.255）。饲养空间分配较大的猪的平均日采食量升高（P≤0.05）。饲养在32.2摄氏度且空间分配减少的相互作用使脂肪碘值从66.8增加到70.4（P≤0.05），饱和脂肪酸与不饱和脂肪酸的比例从0.59降低到0.56（P≤0.05），n-6:n-3从23.56增加到25.27（P≤0.05）。空间分配减少导致腹脂重量降低（P≤0.05）。虽然温度升高不影响腹脂重量，但饲养在32.2摄氏度的猪的生肉片和熟肉片重量降低（P≤0.05），培根的瘦肉百分比增加（P≤0.05），培根片的瘦肉与脂肪比例增加（P≤0.05），生肉片评分增加（P≤0.05），腹脂中的胶原蛋白含量增加（P≤0.05）。其中一些变化可能是由脂质代谢变化引起的。在32.2摄氏度的猪中增加空间分配会降低脂肪组织中脂肪酸合酶（P = 0.03）和硬脂酰辅酶A去饱和酶-1（P = 0.08）的mRNA表达。本研究结果表明，饲养在高于热中性区温度的猪的生长、胴体脂质质量和培根质量下降；然而，增加饲养空间分配可能是减轻温度应激负面影响的一种方法。
