Effects of glucose and volatile fatty acids on blood ghrelin concentrations in calves before and after weaning
Effects of glucose and volatile fatty acids on blood ghrelin concentrations in calves before and after weaning
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DOI：
10.2527/jas.2012-5344
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发表时间：
2012-12-01
影响因子：
3.3
通讯作者：
Taniguchi, K.
中科院分区：
文献类型：
--
作者：
Fukumori, R.;Mita, T.;Taniguchi, K.
研究了断奶前后犊牛饲喂和静脉注射葡萄糖和 VFA 对血液生长素释放肽浓度的影响。八头荷斯坦小牛饲喂全脂牛奶，允许自由采食固体饲料，并在 7 周时断奶。测量在第 2、4、6、9、11 和 13 周进行，此时从 4 头犊牛早上喂食前 10 分钟到喂食后 120 分钟，每隔 10 分钟间隔一次，通过导管采集颈静脉血样本（实验 1）。另外 4 头同龄小牛使用导管静脉注射葡萄糖（1.0 mmol.kg BW-1）和 VFA 溶液（2.4 mmol.kg BW-1，醋酸盐：丙酸盐：丁酸盐，比例为 6:3:1），并根据注射时间暂时采集颈静脉血样（实验 2）。在Exp。 1、各年龄段饲喂后血ghrelin浓度均下降(P<0.05)。然而，与断奶前相比，断奶后期间餐前生长素释放肽浓度较低（P = 0.025），且餐后生长素释放肽抑制程度往往更大（P = 0.084）。断奶前喂养后血糖浓度升高（P < 0.05），而断奶后血液醋酸盐浓度升高（P < 0.05）。在Exp。如图 2 所示，在整个期间，注射 VFA 引起的血液 ghrelin 浓度下降幅度大于注射葡萄糖（P < 0.05）。这些结果表明，断奶会降低血液生长素释放肽的基础浓度，因为来自瘤胃发酵的循环VFA可能比葡萄糖更强烈地降低血液生长素释放肽浓度。
The effects of feeding and intravenous injections of glucose and VFA on blood ghrelin concentrations were investigated in calves before and after weaning. Eight Holstein bull calves were fed whole milk, allowed free access to solid feeds, and weaned at 7 wk. Measurements were carried out at 2, 4, 6, 9, 11, and 13 wk, at which time jugular blood samples were taken from 4 calves through a catheter from 10 min before to 120 min after their morning feed at 10 min intervals (Exp. 1). An additional 4 calves of the same age were intravenously injected with glucose (1.0 mmol.kg BW-1) and a solution of VFA (2.4 mmol.kg BW-1, acetate: propionate: butyrate in a 6: 3: 1 ratio) using a catheter, and jugular blood samples were taken temporally relative to the injection time (Exp. 2). In Exp. 1, blood ghrelin concentrations decreased (P < 0.05) after feeding at all ages. However, preprandial ghrelin concentrations were less (P = 0.025) and the degree of postprandial depression of ghrelin tended to be greater during the postweaning period (P = 0.084) than during the preweaning period. Blood glucose concentrations increased after feeding during the preweaning period (P < 0.05), whereas blood acetate concentrations increased during the postweaning period (P < 0.05). In Exp. 2, injection of VFA induced a greater decrease in blood ghrelin concentrations than glucose injection throughout the entire period (P < 0.05). These results indicate that weaning reduces the basal concentration of blood ghrelin because the circulating VFA derived from ruminal fermentation may more strongly depress blood ghrelin concentrations than glucose.