日糧有機鋅減輕熱應激對豬腸道完整性和機體代謝的影響

畜牧編輯

　　2015. J. Anim. Sci. 93(10):4702-4713
　　日糧有機鋅減輕熱應激對豬腸道完整性和機體代謝的影響

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

　　日糧鋅（無機鋅、有機鋅或氨基酸鋅）對正常腸道屏障功能和上皮細胞的再生是非常重要的。熱應激會損傷腸道完整性和動物能量攝入，因此可能有必要采取營養調節措施來改善健康、生長性能和動物福利。本試驗的目的在于評估2種不同鋅以及降低能量攝入對12h熱應激生長豬腸道完整性的影響。試驗選用36頭生長豬，對照組（CON）日糧中添加120ppm鋅（硫酸鋅），試驗組（ZnAA）日糧中添加60mg/kg無機鋅（硫酸鋅）和60mg/kg氨基酸鋅。17天后，對照組豬只分為三組，處理分別為：1）適宜溫度，自由采食（適溫組，TN-CON）；2）高溫（37℃），自由采食（熱應激組，HS-CON）；3）適宜溫度，采食量同高溫組（對照飼喂組，PFTN）。氨基酸鋅處理組全為高溫處理（氨基酸鋅組，HS-ZnAA）。環境溫度處理12后，屠宰所有豬只，分析血液和組織生物能量標記物（bioenergetics stress markers）和回腸、結腸完整性。與適溫對照組相比，高溫熱應激顯著增加了直腸溫度和呼吸速率（P＜0.05）。熱應激組（HS-CON）和對照飼喂組（PFTN）顯著降低了回腸絨毛和隱窩形態。與適溫組豬只相比，熱應激組（HS-CON）和對照飼喂組（PFTN）豬只回腸完整性（葡聚糖通量和跨上皮電阻）顯著降低。但是，氨基酸鋅有減輕熱應激對回腸完整性損傷的趨勢。熱應激組（HS-CON）和對照飼喂組（PFTN）提高了回腸粘蛋白2蛋白豐度。熱應激（HS-CON）和對照飼喂（PFTN）對結腸黏膜完整性沒有顯著影響。與熱應激組（HS-CON）相比，氨基酸鋅組豬只血中內毒素水平有降低的趨勢。總之，熱應激和低采食量會損傷腸道完整性，而氨基酸鋅能調節其部分負面影響。

　　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。本文由上海亙泰企業供稿，特此感謝！