Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA.
Poult Sci. 2011 Oct;90(10):2295-300. doi: 10.3382/ps.2010-01173.
The peptide transporter 1 (PepT1) transports di- and tripeptides from the lumen of the small intestine into the enterocyte. Expression of this transporter is affected by numerous factors, including feed restriction. During a fasting state, PepT1 is thought to be regulated by peroxisome proliferator-activated receptor α (PPARα). The objective of this study was to evaluate the effects of a feed restriction-refeeding regimen on expression of chicken PepT1 and PPARα. Ten-day-old broiler chicks were placed on a 24-h feed restriction with 6 birds sampled before and after the restriction. Following feed restriction, the remaining birds were divided into 3 groups: continuously fasted, refed-food withdrawn, and refed ad libitum. The duodenum, jejunum, and ileum were sampled 1, 2, 3, 5, and 7 h post feed restriction. Expression of PepT1 and PPARα increased almost 2-fold post feed restriction (P < 0.002). A significant group × time interaction was observed for PPARα, with the continuously fasted group showing a peak at 29 h postrestriction (P = 0.002). A group × segment interaction was found for both PepT1 (P = 0.002) and PPARα (P = 0.01); within the continuously fasted group, PepT1 expression was greatest in the jejunum (P < 0.001) and ileum (P = 0.01) when compared with the duodenum. No difference was observed between the jejunum and ileum. The PPARα expression was greatest in the jejunum (P = 0.03) when compared with the duodenum, with no difference between the jejunum and ileum or between the duodenum and ileum. The increase in PepT1 expression during a time of reduced feed intake suggests the importance of having transporters ready to scavenge any available luminal nutrients. The concurrent increase in PPARα suggests a possible regulatory role for this receptor in the regulation of PepT1 during feed restriction.
肽转运蛋白 1(PepT1)将二肽和三肽从小肠腔转运到肠细胞内。这种转运蛋白的表达受许多因素的影响,包括饲料限制。在禁食状态下,PepT1 被认为受过氧化物酶体增殖物激活受体 α(PPARα)调节。本研究的目的是评估饲料限制-再喂养方案对鸡 PepT1 和 PPARα表达的影响。将 10 日龄肉鸡置于 24 小时的饲料限制中,在限制前后采集 6 只鸡的样本。在饲料限制后,剩余的鸡分为 3 组:持续禁食、撤食再喂养和自由采食再喂养。在饲料限制后 1、2、3、5 和 7 小时,采集十二指肠、空肠和回肠样本。饲料限制后 PepT1 和 PPARα 的表达增加了近 2 倍(P < 0.002)。PPARα 观察到显著的组×时间相互作用,持续禁食组在限制后 29 小时达到峰值(P = 0.002)。PepT1(P = 0.002)和 PPARα(P = 0.01)都观察到组×节段的相互作用;在持续禁食组中,与十二指肠相比,空肠(P < 0.001)和回肠(P = 0.01)中 PepT1 的表达最高。空肠和回肠之间没有差异。与十二指肠相比,空肠中 PPARα 的表达最高(P = 0.03),空肠和回肠之间以及十二指肠和回肠之间没有差异。在饲料摄入减少期间,PepT1 表达的增加表明转运蛋白在摄取任何可用的腔内容物营养素方面具有重要作用。PPARα 的同时增加表明该受体在饲料限制期间对 PepT1 的调节中可能具有调节作用。