Influence of non-confinement rearing under high infectious pressure from Mycoplasma hyopneumoniae: Pig performance, acute phase proteins and cortisol assessment

Abstract

The objective of this study was to evaluate serum concentrations of acute phase proteins (APP), haptoglobin (HPT), alpha 1-acid glycoproteins (AGP) and cortisol in indoor or outdoor raised pigs over time and under high pressure of Mycoplasma hyopneumoniae, and to determine whether changes in APPs were associated with pig performance. Two groups of 10 pigs each were raised indoors from weaning to slaughter (group 1), and two groups of 10 pigs each of same age and health status were raised outdoors (group 2). Serum samples were taken from each pig at weaning (at day 21 of lactation), at day 60, 90, 120 and 150 days of age. Production data (average daily gain, ADG, feed conversion ratio, FC), seropositivity to M. hyopneumoniae, HPT, AGP and cortisol were evaluated. In indoor raised pigs HPT persistently increased, in outdoor raised ones a sharp increase occurred after a cold weather period. AGP was negatively correlated with body weight, indicating that an activation of cellular immune response negatively effects growth rate of the growing finishing pigs.