代乳粉水平对羔羊血液指标和肠道屏障功能的影响

【背景】代乳粉的合理利用对于提高羔羊健康和成活率具有重要意义,但代乳粉饲喂水平对羔羊免疫功能和肠道屏障功能的影响仍不清楚,羔羊免疫功能发育和肠道健康发育所需的最佳代乳粉饲喂水平仍无定论。【目的】从羔羊血液学指标动态变化规律、回肠和结肠组织形态、抗氧化指标、免疫指标以及肠道屏障功能相关基因表达量的角度分析代乳粉饲喂水平对羔羊免疫功能和肠道屏障功能的影响。【方法】选用16只初生重接近的初生湖羊公羔,随机分成两组,分别为对照组（CON,代乳粉每日饲喂量为羔羊体重的2%）和高饲喂水平组（H,代乳粉每日饲喂量为羔羊体重的4%）。所有羔羊从7日龄开始断母乳饲喂代乳粉,49日龄时屠宰。【结果】代乳粉饲喂水平对羔羊白细胞数、淋巴细胞数、中性粒细胞数、红细胞数和血红蛋白浓度影响不显著（P＞0.05）。21—49d羔羊淋巴细胞数、红细胞数、血红蛋白浓度随日龄逐渐增加,49日龄时显著较高（P＜0.05）,而中性粒细胞淋巴细胞比49日龄时显著较低（P＜0.05）。H组羔羊回肠绒毛高度显著高于CON组（P＜0.05）,回肠和结肠隐窝深度显著低于CON组（P＜0.05）。回肠和结肠丙二醛（MDA）含量和免疫球蛋白A（IgA）含量显著低于CON组（P＜0.05）。结肠Claudin4表达量显著低于CON组（P＜0.05）,回肠和结肠肿瘤坏死因子（TNF-α）表达量均显著低于CON组（P＜0.05）。【结论】高代乳粉饲喂水平可以降低肠道组织氧化损伤,促进肠绒毛发育,降低肠道物理屏障损伤进而减少肠道免疫反应。生产中可以通过提高早期羔羊代乳粉饲喂水平促进羔羊肠道健康发育。

Effects of Milk Replacer Feeding Level on Hematology Index and Gut Barrier Function in Lambs

【Background】 The application of milk replacer powder has important significance for improving the health and survival rate of lambs. However, the effects of milk replacer feeding levels on immune function and intestinal barrier function of lambs were still unclear. The optimal level of milk replacer for development of immune function and intestinal health is still inconclusive. 【Objective】 The objective of this experiment was to analyze the effects of the milk replacer feeding level on the immune function and intestinal barrier function of lambs through the dynamic of hematological indicators, the morphology of ileum and colon, antioxidant index, immune index and expression of intestinal barrier function related genes.【Method】16 newborn lambs were randomly divided into two groups: the control group (CON, milk replacer feeding level was 2% of average body weight) and the intensive feeding group (H, milk replacer feeding level was 4% of their average body weight). All lambs were fed milk replacer from the 7th day of age and were slaughtered at 49 days of age. 【Result】The results showed that the milk replacer feeding level had no significant effects on leukocyte count, lymphocyte count, neutrophil count, red blood cell count and hemoglobin concentration (P＞0.05). The number of lymphocytes, red blood cells and hemoglobin in the 21-49d lambs increased gradually with age, significantly higher at 49 days of age (P＜0.05), while neutrophil lymphocytes were significantly lower than at 49 days (P＜0.05). The ileal villus height of the H group was significantly higher than that of the CON group (P＜0.05), the ileum and colon crypt depth was significantly lower than that of the CON group (P＜0.05), the ileal and colonic malondialdehyde (MDA) content and immunoglobulin A (The content of IgA) was significantly lower than that of CON group (P＜0.05). The expression of Claudin4 in colon was significantly lower than that in CON group (P＜0.05), and the expression of tumor necrosis factor (TNF-α) in ileum and colon was significantly lower than that in CON group (P＜0.05). 【Conclusion】The intensive milk replacer feeding could reduce intestinal oxidative damage, promote intestinal villus development, reduce intestinal physical barrier damage and reduce intestinal immune response. In the sheep production, an intensive milk replacer-feeding program benefits to the healthy intestinal development.