Improvement of growth performance and parameters of intestinal function in liquid fed early weanling pigs1

Liquid feeding, a widely used technique, has been applied as a feeding technique commonly in global swine production. The objective of this study was to evaluate the effects of liquid feeding on growth performance, nutrient digestibility, and intestinal barrier functions during the early weaning period in pigs. Three hundred and sixty 24-d-old weanling pigs (Duroc × Landrace × Yorkshire) with BW of 6.98 ± 0.15 kg were randomly assigned to a control diet (dry fed basal diet, CON) or as meal mixed with water in the ratio 1:4 (liquid fed basal diet, LF) with 6 replicates per treatment and 30 weanling pigs per replicate. The study lasted 7 d. On days 4 to 7, fresh fecal samples were collected to evaluate apparent total tract digestibility (ATTD) of nutrients. After 7 d, 2 weanling pigs per pen were euthanized and physiological samples were obtained. Results showed that LF increased (P < 0.05) ADG (281 g vs. 183 g), ADFI (374 g vs. 245 g), and final BW (8.95 kg vs. 8.26 kg) compared with CON. Compared with CON, LF significantly decreased (P < 0.05) serum cortisol and d-lactate concentrations as well as the activity of diamine oxidase, enhanced (P < 0.05) the ATTD of ether extract and ash, increased (P < 0.05) the activities of amylase, lipase, and lactase in the jejunal mucosa. Furthermore, LF had higher (P < 0.05) villus height and villi height:crypt depth and increased (P < 0.05) mRNA expressions of insulin-like growth factors-1 receptor (IGF-1R), claudin-2 (CLDN-2), zonula occludens-1 (ZO-1), and zonula occludens-2 (ZO-2) in the jejunum. Moreover, LF had lower (P < 0.05) abundances of total bacteria and Escherichia coli and higher (P < 0.05) concentrations of acetic acid and butyric acid in cecal digesta. Altogether, the results indicated that liquid feeding not only promoted growth performance but also improved intestinal health by enhancing gut barrier functions in weanling pigs.