Partial Na+ dependence of DL-2-hydroxy-4-(methylthio)butanoic acid uptake in the chicken small intestine.

Methionine hydroxy analogue DL-2-hydroxy-(4-methylthio)butanoic acid (HMTBA) is commonly used as a supplemental source of Met in commercial animal diets. To better understand the uptake of this analogue by the chicken intestine, the aim of the present study was to assess the contribution of Na+ gradient on HMTBA accumulation in everted sacs of the chicken small intestine (duodenum, jejunum, and ileum). In the presence of an H+ gradient, uptake was lower in the absence of Na+ along the chicken small intestine, although no significant differences were detected in the duodenum. In contrast, in the absence of an H+ gradient, no significant differences were detected between the 2 Na+ conditions. In conclusion, the observed relationship between Na+ and H+ dependence indicates the participation of the apical Na+/H+ exchanger in HMTBA uptake in the chicken small intestine.