Importance of sanitary environment for growth performance and plasma nutrient homeostasis during the post-weaning period in piglets.

Deterioration of sanitary conditions in piggeries is known to limit growth performance through inducing a moderate immune response. This article reports the results of an experiment performed to reproduce the consequences of bad sanitary conditions on growth performance and nutrient plasma concentrations of piglets after weaning. We propose to use these experimental conditions as a model for studying the interactions between nutrition and pig health. In this experiment, 20 pairs of littermate piglets were selected and weaned at 28 days of age on the basis of their body weight. Within each pair, piglets were pair-fed and each one was affected to one of the two experimental groups. The first group was housed in a clean environment and was fed an antibiotic supplemented standard diet. The second group was kept in unsanitary rooms, mixed with non-experimental piglets and was fed the same standard diet but without antibiotic supplementation. Compared to pigs kept in the clean environment, piglets kept in the unsanitary environment had significantly lower rate of weight gain and feed efficiency from weaning to 20 d post weaning then from 36 - 45 d post weaning. They also displayed higher plasma concentrations of haptoglobin, copper, vitamin B12 and lysine but lower concentrations of glutathione, pyridoxal-5-phosphate, folic acid, threonine and tryptophan. Our results showed that a reduction of growth performance and a modification of nutrient utilization can be induced by decreasing the sanitary quality of environment where pigs are kept after weaning and after transition to another building. This response could be explained by a moderated activation of body defences.