日粮有机锌减轻热应激对猪肠道完整性和机体代谢的影响

畜牧编辑

　　2015. J. Anim. Sci. 93(10):4702-4713
　　日粮有机锌减轻热应激对猪肠道完整性和机体代谢的影响

　　S. C. Pearce, M.-V. Sanz Fernandez, J. Torrison, M. E. Wilson, L. H. Baumgard和N. K. Gabler

　　日粮锌（无机锌、有机锌或氨基酸锌）对正常肠道屏障功能和上皮细胞的再生是非常重要的。热应激会损伤肠道完整性和动物能量摄入，因此可能有必要采取营养调节措施来改善健康、生长性能和动物福利。本试验的目的在于评估2种不同锌以及降低能量摄入对12h热应激生长猪肠道完整性的影响。试验选用36头生长猪，对照组（CON）日粮中添加120ppm锌（硫酸锌），试验组（ZnAA）日粮中添加60mg/kg无机锌（硫酸锌）和60mg/kg氨基酸锌。17天后，对照组猪只分为三组，处理分别为：1）适宜温度，自由采食（适温组，TN-CON）；2）高温（37℃），自由采食（热应激组，HS-CON）；3）适宜温度，采食量同高温组（对照饲喂组，PFTN）。氨基酸锌处理组全为高温处理（氨基酸锌组，HS-ZnAA）。环境温度处理12后，屠宰所有猪只，分析血液和组织生物能量标记物（bioenergetics stress markers）和回肠、结肠完整性。与适温对照组相比，高温热应激显著增加了直肠温度和呼吸速率（P＜0.05）。热应激组（HS-CON）和对照饲喂组（PFTN）显著降低了回肠绒毛和隐窝形态。与适温组猪只相比，热应激组（HS-CON）和对照饲喂组（PFTN）猪只回肠完整性（葡聚糖通量和跨上皮电阻）显著降低。但是，氨基酸锌有减轻热应激对回肠完整性损伤的趋势。热应激组（HS-CON）和对照饲喂组（PFTN）提高了回肠粘蛋白2蛋白丰度。热应激（HS-CON）和对照饲喂（PFTN）对结肠黏膜完整性没有显著影响。与热应激组（HS-CON）相比，氨基酸锌组猪只血中内毒素水平有降低的趋势。总之，热应激和低采食量会损伤肠道完整性，而氨基酸锌能调节其部分负面影响。

　　Dietary organic zinc attenuates heat stress–induced changes in pig intestinal integrity and metabolism
　　S. C. Pearce, M.-V. Sanz Fernandez, J. Torrison, M. E. Wilson, L. H. Baumgard and N. K. Gabler

　　Dietary zinc (inorganic and organic or zinc AA complex forms) is essential for normal intestinal barrier function and regeneration of intestinal epithelium. Given that heat stress (HS) exposure can negatively affect intestinal integrity and caloric intake, possible nutritional mitigation strategies are needed to improve health, performance, and well-being. Therefore, our objective was to evaluate 2 dietary zinc sources and reduced caloric intake on intestinal integrity in growing pigs subjected to 12 h of HS. A total of 36 pigs were fed 1 of 2 diets: 1) a control diet (CON; 120 mg/kg of zinc from zinc sulfate) or 2) 60 mg/kg from zinc sulfate and 60 mg/kg from zinc AA complex (ZnAA). After 17 d, the CON pigs were then exposed to thermal neutral (TN) conditions with ad libitum intake (TN-CON), HS (37°C) with ad libitum intake (HS-CON), or pair-fed to HS intake under TN conditions (PFTN); the ZnAA pigs were exposed to only HS (HS-ZnAA). All pigs were sacrificed after 12 h of environmental exposure, and blood and tissue bioenergetics stress markers and ex vivo ileum and colon integrity were assessed. Compared with TN-CON, HS significantly (P < 0.05) increased rectal temperatures and respiration rates. Ileum villus and crypt morphology was reduced by both pair-feeding and HS. Both PFTN and HS-CON pigs also had reduced ileum integrity (dextran flux and transepithelial resistance) compared with the TN-CON pigs. However, ZnAA tended to mitigate the HS-induced changes in ileum integrity. Ileum mucin 2 protein abundance was increased due to HS and pair-feeding. Colonic integrity did not differ due to HS or PFTN treatments. Compared with the HS-CON, HS-ZnAA pigs tended to have reduced blood endotoxin concentrations. In conclusion, HS and reduced feed intake compromised intestinal integrity in pigs, and zinc AA complex source mitigates some of these negative effects。本文由上海亘泰企业供稿，特此感谢！