Morrison S Y, Pastor J J, Quintela J C, Holst J J, Hartmann B, Drackley J K, Ipharraguerre I R
Department of Animal Science, University of Illinois, Urbana 61801.
Lucta S. A., Montornès del Vallès, Spain 08170.
J Dairy Sci. 2017 Mar;100(3):1940-1945. doi: 10.3168/jds.2016-11810. Epub 2016 Dec 29.
Diarrhea episodes in dairy calves involve profound alterations in the mechanism controlling gut barrier function that ultimately compromise intestinal permeability to macromolecules, including pathogenic bacteria. Intestinal dysfunction models suggest that a key element of intestinal adaptation during the neonatal phase is the nutrient-induced secretion of glucagon-like peptide (GLP)-2 and associated effects on mucosal cell proliferation, barrier function, and inflammatory response. Bioactive molecules found in Olea europaea have been shown to induce the release of regulatory peptides from model enteroendocrine cells. The ability to enhance GLP-2 secretion via the feeding of putative GLP-2 secretagogues is untested in newborn calves. The objectives of this study were to determine whether feeding a bioactive extract from Olea europaea (OBE) mixed in the milk replacer (1) can stimulate GLP-2 secretion beyond the response elicited by enteral nutrients and, thereby, (2) improve intestinal permeability and animal growth as well as (3) reduce the incidence of diarrhea in preweaning dairy calves. Holstein heifer calves (n = 60) were purchased, transported to the research facility, and blocked by body weight and total serum protein and assigned to 1 of 3 treatments. Treatments were control (CON), standard milk replacer (MR) and ad libitum starter; CON plus OBE added into MR at 30 mg/kg of body weight (OBE30); and CON plus OBE added into MR at 60 mg/kg of body weight (OBE60). The concentration of GLP-2 was measured at the end of wk 2. Intestinal permeability was measured at the onset of the study and the end of wk 2 and 6, with lactulose and d-mannitol as markers. Treatments did not affect calf growth and starter intake. Compared with CON, administration of OBE60 increased the nutrient-induced response in GLP-2 by about 1 fold and reduced MR intake during the second week of study. Throughout the study, however, all calves had compromised intestinal permeability and a high incidence of diarrhea. The GLP-2 response elicited by OBE60 did not improve intestinal permeability (lactulose-to-d-mannitol ratio) and incidence of diarrhea over the course of the preweaning period. The response in GLP-2 secretion to the administration of OBE reported herein warrants further research efforts to investigate the possibility of improving intestinal integrity through GLP-2 secretion in newborn calves.
犊牛腹泻发作涉及控制肠道屏障功能机制的深刻改变，最终会损害肠道对包括病原菌在内的大分子的通透性。肠道功能障碍模型表明，新生期肠道适应的一个关键因素是营养物质诱导的胰高血糖素样肽（GLP）-2分泌以及对黏膜细胞增殖、屏障功能和炎症反应的相关影响。已证明油橄榄中发现的生物活性分子可诱导模型肠内分泌细胞释放调节肽。通过喂食假定的GLP-2促分泌剂来增强GLP-2分泌的能力在新生犊牛中尚未得到测试。本研究的目的是确定在代乳粉中添加油橄榄生物活性提取物（OBE）（1）是否能刺激GLP-2分泌，使其超出肠内营养物质引发的反应，从而（2）改善肠道通透性和动物生长，以及（3）降低断奶前犊牛腹泻的发生率。购买了60头荷斯坦小母牛犊牛，运至研究设施，按体重和总血清蛋白进行分组，并分配至3种处理之一。处理方式为对照组（CON），即标准代乳粉（MR）并随意采食开食料；CON组加上以30 mg/kg体重添加到MR中的OBE（OBE30）；以及CON组加上以60 mg/kg体重添加到MR中的OBE（OBE60）。在第2周结束时测量GLP-2浓度。在研究开始时以及第2周和第6周结束时，以乳果糖和D-甘露醇为标志物测量肠道通透性。处理方式未影响犊牛生长和开食料摄入量。与CON组相比，OBE60处理使营养物质诱导的GLP-2反应增加了约1倍，并在研究的第二周减少了MR摄入量。然而，在整个研究过程中，所有犊牛的肠道通透性均受损，腹泻发生率较高。在断奶前阶段，OBE60引发的GLP-2反应并未改善肠道通透性（乳果糖与D-甘露醇比值）和腹泻发生率。本文报道的OBE给药后GLP-2的反应值得进一步研究，以探讨通过新生犊牛GLP-2分泌改善肠道完整性的可能性。
