Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
Trouw Nutrition R&D, PO Box 299, 3800 AG, Amersfoort, the Netherlands.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad050.
The objective of this study was to compare the effects of post-ruminal provision of Ca-butyrate (CaB) when delivered via abomasal dosing, and Ca-gluconate (CaG) when provided ruminally using a rumen protected form or using an unprotected form via abomasal dosing on short-chain fatty acid (SCFA) concentration throughout the GIT, nutrient digestibility, GIT barrier function, ruminal SCFA absorption, ruminal morphometrics, intestinal brush border enzyme activity, and blood parameters for beef heifers. Thirty-two beef heifers fitted with ruminal cannulas were used in a randomized complete block design and assigned to one of four treatments: 1) negative control (ruminal infusion of double-distilled water; CON); 2) abomasal infusion of CaB (AB; 0.0029% of BW); 3) abomasal infusion of CaG (AG; 0.0077% of BW); and 4) ruminal infusion of a hydrogenated fat-embedded CaG (RG; 0.0192% of BW) to provide ruminal protection. Excluding CON, treatments were designed to deliver the same amount of butyrate in the small intestine. Heifers were housed in individual pens and DMI was limited to 95% of voluntary intake to minimize a potential confounding effect of DMI on treatment responses. Total GIT barrier function was assessed on day 17 and SCFA disappearance was evaluated on day 21 using the temporarily isolated and washed reticulo-rumen technique. On day 28, heifers were slaughtered, and ruminal and colonic digesta were collected to assess SCFA concentration. Additionally, ruminal, jejunal, and colonic tissues were collected to assess SCFA fluxes and regional barrier function ex vivo using the Ussing chamber technique. For colonic digesta, both AB and CaG treatments reduced the proportion of acetate (P < 0.05) and increased the proportion on propionate (P < 0.05) compared to CON. Relative to CON, AB but not CaG treatments increased in vivo ruminal disappearance of total SCFA (P = 0.01), acetate (P = 0.03), propionate (P = 0.01), and butyrate (P > 0.01). Treatments did not affect (P ≥ 0.10) acetate and butyrate fluxes in the ruminal and colonic tissues when measured ex vivo; however, when compared with CON, AB tended to decrease (P = 0.09) mannitol flux across ruminal tissue. In addition, mannitol flux was affected (P < 0.01) by region, with greater mannitol flux across the jejunum than rumen and colon. We conclude that while both abomasal infusion of CaB and CaG affect the molar proportion of acetate and propionate in the colon, only abomasal CaB stimulated ruminal SCFA absorption for growing beef heifers.
本研究的目的是比较瘤胃后提供钙丁酸盐（CaB）和钙葡萄糖酸盐（CaG）对短链脂肪酸（SCFA）浓度、养分消化率、胃肠道屏障功能、瘤胃 SCFA 吸收、瘤胃形态计量学、肠刷状缘酶活性和血液参数的影响。32 头安装有瘤胃套管的肉牛采用随机完全分组设计，并分为以下四组之一：1）阴性对照（瘤胃输注双蒸馏水；CON）；2） 瘤胃输注 CaB（AB；BW 的 0.0029%）；3） 瘤胃输注 CaG（AG；BW 的 0.0077%）；4） 瘤胃输注氢化脂肪包埋 CaG（RG；BW 的 0.0192%），以提供瘤胃保护。除 CON 外，所有处理均旨在使小肠中吸收相同量的丁酸。牛被安置在单独的围栏中，DMI 限制在自愿摄入量的 95%以内，以尽量减少 DMI 对处理反应的潜在混杂影响。第 17 天采用暂时分离和冲洗皱胃技术评估总胃肠道屏障功能，第 21 天评估 SCFA 消失情况。第 28 天，对牛进行屠宰，并收集瘤胃和结肠内容物以评估 SCFA 浓度。此外，使用 Ussing 室技术收集瘤胃、空肠和结肠组织，以评估 SCFA 通量和局部屏障功能。对于结肠内容物，AB 和 CaG 处理均降低了乙酸（P < 0.05）的比例，增加了丙酸（P < 0.05）的比例。与 CON 相比，AB 处理增加了体内瘤胃总 SCFA（P = 0.01）、乙酸（P = 0.03）、丙酸（P = 0.01）和丁酸（P > 0.01）的消失。当 ex vivo 测量时，处理并没有影响（P ≥ 0.10）在瘤胃和结肠组织中乙酸和丁酸的通量；然而，与 CON 相比，AB 处理 tended 降低了（P = 0.09）甘露醇通过瘤胃组织的通量。此外，甘露醇通量受区域影响（P < 0.01），空肠的甘露醇通量大于瘤胃和结肠。我们得出结论，尽管瘤胃内输注 CaB 和 CaG 都会影响结肠中乙酸和丙酸的摩尔比例，但只有瘤胃内输注 CaB 刺激了生长肉牛的瘤胃 SCFA 吸收。
