category: feed additives
authors: a. mereu, j. j. pastor, d. chin, g. rimbach, i. r. ipharraguerre
book/journal:journal of animal science volume 94, supplement 2, 141.
in mice, weaning stress increases intestinal permeability partly through a mechanism that involves tnf-α, intestinally-produced glucocorticoids, and myosin like chain kinase (mlck). recent evidence suggests that this interplay takes place predominantly in the colonic mucosa and has long-lasting effects on intestinal development and function. interestingly, the impact of weaning-induced intestinal dysfunction is inversely correlated to age at weaning. however, little is known about the impact that pre-weaning growth has on post-weaning gut permeability and animal performance. the aim of this experiment was to investigate the effect of pre-weaning growth on intestinal permeability and underlying regulatory pathways. to this end, 18 piglets ((lw x ld) x pietrain) were weighed and identified at birth. at weaning (21 d of age) piglets were divided into two groups (n = 9): fast growers (fg) or slow growers (sg) according to their growth rate from birth to weaning. thereafter, piglets were housed individually and fed ad libitum non-medicated pre-starter (21 - 35 d) and starter (35 - 56 d) feeds. individual bw and feed intake were registered weekly. on day 56, plasma for cortisol determination and recovery of permeability markers (co-edta and mannitol) was obtained 1 h after marker intragastric infusion. immediately after, ascendant colon samples were harvested for measurement of cortisol, tnf-α and mlck mrna in colonic mucosa. performance data were analyzed with a mixed-effect model with repeated measures in which pig was treated as random and treatment, week and its interaction were considered fixed effects. pigs in the sg group had a lower pre-weaning growth rate (181 vs. 208 ± 13.1 g/d; p < 0.04) and bw at d 21 (6.0 vs. 6.3 ± 0.005 kg; p < 0.05) than fg counterparts. at d 56, plasma cortisol was not different between groups. however, the ratio co/mannitol in plasma was higher in sg than fg (28.7 vs. 11.9 ± 13.0; p < 0.001). in addition, sg pigs had a higher concentration of cortisol (20.0 vs. 2.5 ± 2.7 ng/mg of protein; p < 0.001) and tnf-a (0.15 vs. 0.09 ± 0.01 ng/mg of protein; p < 0.001) in the colonic mucosa. interestingly, abundance of mlck mrna in colon mucosa was 35% lower (p < 0.05) in fg compared with sg. in conclusion, pre-weaning growth rate has a long-lasting impact on gut permeability and the mechanism underlying this phenomenon appears to be regulated locally at the colon epithelium