category: feed additives
authors: mereu, a., pastor, j.j., chin, d., tedo, g., rimbach, g. and ipharraguerre, i.r.
book/journal:16th international conference on production diseases in farm animals, wageningen, 20th to 23rd of june, 2016
weaning-induced stress is associated with intestinal dysfunction and impaired piglet growth. in addition, body weight at weaning has life-long effects on pig performance. therefore, the aim of this work was to elucidate if variation in pre-weaning growth correlate with differences in intestinal sensitivity to stress long after weaning. . 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. on day 56 ascendant colon samples were harvested to measure the protein concentration of cortisol, tnf-α, crh and the mrna abundance of glucocorticoid receptor (gr), 11β-hydroxylase (cyp11b1), and 11β-hydroxysteroid dehydrogenase type 1 (hsd11b1) 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. colonic measurements were analyzed using a student’s t tests. pigs in the sg group had a lower pre-weaning growth rate (181 vs. 208 g/d; p < 0.04) and bw at d 21 (6.0 vs. 6.3 kg; p < 0.05) than fg counterparts. at d 56, no differences were observed in colonic cyp11b1, crh, and gr between groups. compared to sg, however, fg pigs had lower levels of colonic cortisol (20 vs. 2.5; p < 0.001) and tnf-α (0.15 vs 0.09; p < 0.01). in addition, the expression of hsd11b1 gene, which encodes for the enzyme that reduces cortisone to the active hormone cortisol, awas was downregulated (1 vs 0.68; p < 0.004) in the fg group. in conclusion, higher pre-weaning growth rate is associated with decreased intestinal sensitivity to stress , which partly may explain the long-lasting effects in animal performance.