Nutritional management of dairy cows to enhance gut functions

奶牛营养管理增强肠道功能

• 批准号: RGPIN-2018-05825
• 负责人: Oba, Masahito
• 金额: $ 2.11万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=661095
• 关键词: Nutritional; management; dairy; cows; enhance

The objective of the proposed research is to evaluate novel nutritional management approaches to enhance gut functions. I have been working to mitigate sub-acute rumen acidosis (SARA) in dairy cows with the support of my NSERC Discovery Grant. The SARA is a metabolic disorder that negatively affects the health and productivity of ruminants. Feeding high grain diets often causes excess fermentation that results in the accumulation of fermentation acids in the rumen (the first stomach of ruminants), leading to systemic inflammation, feed intake reduction, liver abscesses, lameness, and other metabolic disorders. However, it is noteworthy that some animals maintain high feed intake and milk production even with low rumen pH (i.e., SARA). The variable tolerance observed among animals to this condition is not well understood, and the underlying factors warrant investigation. For the current proposal, I hypothesize that glucagon-like peptide 2 (GLP-2), a hormone released from the distal intestine, plays an important role in enhancing gut functions and mitigates the negative consequences of SARA. Because rumen acidosis and excess hind-gut fermentation often increases the entry of lipopolysaccharide, an endotoxin, into blood circulation, enhancing gut barrier function is considered very important to minimize the negative consequences of excess fermentation in the gut. It is well established that GLP-2 plays an important role in gut development and sound gut function, but it is not known how it is involved in minimizing problems related to SARA. The proposed research will investigate the extent of variation in basal plasma concentration of GLP-2 and postprandial changes in GLP-2 in response to dietary treatments and stage of lactation. In addition, relationships between plasma GLP-2 concentrations and nutrient digestibility, gut barrier function, and gene expression in ruminal epithelial cells will be evaluated to understand the importance of GLP-2 in gut functions of dairy cows. Then, using an acidosis challenge model, where 5 kg of ground grain will be dosed into the rumen after a 2-d 50% feed restriction, I will evaluate if continuous administration of a GLP-2 analogue decreases the negative effects of rumen acidosis in dairy cows. Furthermore, I will evaluate several nutritional management approaches to potentially enhance plasma GLP-2 concentration, including, but not limited to, supplements of sugar, processed grains, and butyrate. I hypothesize that enhancing GLP-2 secretion will minimize systemic inflammation indicated by the serum concentration of acute phase proteins. The proposed research is expected to contribute to sustainable dairy production in Canada by minimizing systemic metabolic problems caused by SARA and excess hind-gut fermentation.

拟议研究的目的是评估新的营养管理方法，以增强肠道功能。 我一直在努力减轻亚急性瘤胃酸中毒（SARA）在奶牛与我的NSERC发现补助金的支持。SARA是一种代谢紊乱，对反刍动物的健康和生产力产生负面影响。饲喂高谷物日粮通常会导致过度发酵，导致发酵酸在瘤胃（反刍动物的第一个胃）中积累，导致全身性炎症、采食量减少、肝脏肿胀、跛行和其他代谢紊乱。然而，值得注意的是，一些动物即使在低瘤胃pH（即，SARA）。在动物中观察到的对这种情况的可变耐受性尚未得到很好的理解，其潜在因素值得研究。对于目前的建议，我假设胰高血糖素样肽2（GLP-2），从远端肠道释放的激素，在增强肠道功能和减轻SARA的负面后果中起着重要作用。由于瘤胃酸中毒和过量的后肠发酵通常会增加脂多糖（一种内毒素）进入血液循环，因此增强肠道屏障功能被认为是非常重要的，以最大限度地减少肠道中过量发酵的负面影响。已经确定GLP-2在肠道发育和良好的肠道功能中发挥重要作用，但尚不清楚它如何参与最大限度地减少SARA相关问题。拟议的研究将研究GLP-2的基础血浆浓度的变化程度和GLP-2的餐后变化对饮食治疗和哺乳阶段的反应。此外，将评估血浆GLP-2浓度与营养物消化率、肠道屏障功能和瘤胃上皮细胞中基因表达之间的关系，以了解GLP-2在奶牛肠道功能中的重要性。 然后，使用酸中毒攻击模型，其中在2天50%饲料限制后将5 kg磨碎的谷物给药至瘤胃中，我将评估GLP-2类似物的连续给药是否降低奶牛瘤胃酸中毒的负面影响。此外，我将评估几种可能提高血浆GLP-2浓度的营养管理方法，包括但不限于补充糖、加工谷物和丁酸盐。我推测，增强GLP-2分泌将使急性期蛋白血清浓度所指示的全身炎症最小化。这项拟议的研究预计将有助于可持续的乳制品生产在加拿大最大限度地减少由SARA和过量后肠发酵引起的全身代谢问题。