Dietary Supplementation of β-Carotene on Growth Performance, Jejunal Permeability and Tight Junction Proteins in Weaned piglets

Abstract

Background: Weaning causes stress syndrome in the newborns, while it can lead to many intestinal diseases. The aim of this study was to determine the dietary supplementation of β-carotene on growth performance, jejunal permeability and tight junction proteins in weaned piglets, and explore the underlying mechanisms by which β-carotene regulates tight junction proteins. The positive control group was fed sow's milk throughout the trial. The negative control group was weaned at d 21 without any supplementation. Two experimental groups of piglets were weaned at d 21 and fed 40 mg/kg or 80 mg/kg β-carotene-supplemented diets from d 14 to d 24, respectively. Blood and the jejunum were collected at d 24. Results: The results showed that β-carotene at 80 mg/kg increased initial and final body weight and average daily feed intake, improved the villus height at d 24 (p<0.05) but reduced crypt depth in weaned piglets at d 24 (p<0.05). Additionally, β-carotene protected intestinal morphology. Supplemental 80 mg/kg β-carotene reduced the concentrations of D-lactic acid and diamine oxidase in serum (p<0.05) but enhanced the mRNA expression of claudin-3, occludin (p<0.05), and zonula occludens protein-1(p>0.05) and the protein levels of claudin-3 (p<0.01), occludin (p<0.05), and zonula occludens protein-1 (p>0.05) in the jejunum at d 24. Using intestinal epithelial cells and a Rac1 inhibitor in vitro, we demonstrated that the β-carotene-induced higher tight junction proteins might depend on the Rac1 pathway. Conclusions: β-carotene improved growth performance and attenuated jejunal permeability and tight junction proteins in weaned piglets, suggesting that β-carotene at 80 mg/kg may be an effective way for keeping healthier intestine of weaning piglets due to weaning.