Dietary Tryptophan Enhanced the Expression of Tight Junction Protein ZO-1 in Intestine.

Dietary amino acids provide various beneficial effects for our health. The aim of the present study was to assess the effects of tryptophan (Trp) supplementation on barrier function. Ninety-six healthy finishing pigs (initial body weight 51.49 ± 1.12 kg) were randomly allocated into 2 treatment groups, control group, and 0.2% Trp group. The control group was fed the basal diet, and 0.2% Trp group was fed basal diet plus 0.2% Trp. The trial period is 60 d. Compared with control group, the mRNA abundance of claudin-3 and zonula occluden-1 (ZO-1) in the jejunum in 0.2% Trp group (P < 0.05) was increased. According to immunohistochemistry and immunoblotting test, the expression of ZO-1 in jejunum in 0.2% Trp group was also significantly increased compared with the control group (P < 0.05). These results revealed that Trp enhanced the expression of tight junction protein ZO-1 in the intestine of pig model. Trp may be potential and beneficial dietary functional factor for regulating the intestinal development and inhibiting intestinal aging.