title: The prolonged effect of glucagon-like peptide 2 pretreatment on growth performance and intestinal development of weaned piglets.
abstract: BACKGROUND
  Glucagon-like peptide 2 (GLP-2) is a potent epithelium-specific intestinal growth factor. The aim of this study was to demonstrate the prolonged effect of GLP-2 on the growth performance of weaned piglets. Forty piglets weaned at the age of 28 d with an average BW of 6.8 ± 0.4 kg were assigned to four treatments: (i) non-challenged control; (ii) LPS-challenged control; (iii) LPS + low GLP-2; and (iv) LPS + high GLP-2. Piglets in groups (i), (ii), and (iv) were s.c. injected with PBS supplemented with human [Gly2]GLP-21-34 at doses of 0, 2 and 10 nmol/kg BW per day for seven consecutive days. BW, gain:feed ratio (G:F), and plasma GLP-2 levels were determined on d 0, 7, and 14 after weaning. Piglets were challenged with i.p. administration of Escherichia coli lipopolysaccharide (LPS) at a dose of 100 μg/kg on d 14 to induce intestinal damage. Twenty-four hours later, intestinal tract samples were collected to assess intestinal morphology and quantify enzyme activity.
  
  
  RESULTS
  Plasma GLP-2 levels decreased after weaning, but in the high GLP-2 group, plasma GLP-2 was maintained on d 7 and even increased to a level higher than the preweaning level on d 14 (P < 0.05). High GLP-2 treatment significantly increased the duodenal, jejunal and ileal weight, as well as the gross weight of the small intestine (SI), and the SI weight index (P < 0.05). LPS caused villous atrophy and disrupted intestinal morphology in the duodenum, jejunum and ileum. GLP-2 also significantly increased the villus height and the villus height/crypt depth ratio (VCR) of the duodenum, jejunum, and ileum (P < 0.05). Histological examination revealed that in GLP-2-treated groups, the integrity of the villus was maintained, and the villus was protected against LPS-induced damage. GLP-2 significantly increased the activity of alkaline phosphatase (AKP), γ-glutamyltranspeptidase (γ-GT), and pancreatic lipase in the duodenum and jejunum (P < 0.05). GLP-2 treatment also significantly increased the average daily gain (ADG) and G:F of piglets at 0 to 7, 7 to 14, as well as 0 to14 d (P < 0.05), resulting in a significant increase of final BW in high GLP-2 pigs (P = 0.016).
  
  
  CONCLUSIONS
  Exogenous GLP-2 improved the growth of weaned piglets and protected them against LPS-induced intestinal damage. These effects may be due to the ability of GLP-2 to promote the secretion of endogenous GLP-2 to stimulate the small intestinal development.
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Qiu Hong
authors.initials: QH
authors.lastname: Deng
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Gang
authors.initials: G
authors.lastname: Jia
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhao
authors.affiliation: College of Animal Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Zheng Li
authors.initials: ZL
authors.lastname: Chen
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Xiao Ling
authors.initials: XL
authors.lastname: Chen
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Guang Mang
authors.initials: GM
authors.lastname: Liu
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130 China.
authors.forename: Kang Ning
authors.initials: KN
authors.lastname: Wang
keywords: Escherichia coli lipopolysaccharide; Glucagon-like peptide-2; Growth performance; Intestinal enzymes; Small intestinal morphology; Weaned piglets