Evaluation of stress and performance of pigs during the nursery phase, using environmental enrichment techniques

ABSTRACT Environmental enrichment is an important tool within production systems to promote welfare and animal health. The aim of this study was to evaluate the effect of enrichment objects on stress of piglets in nursery phase. 32 piglets housed in experimental farm were distributed in 4 groups (n= 8): rope, chain, pet bottle and negative control. Blood samples were collected at the beginning and end of the experiment to count circulating leukocytes and determine non-enzymatic antioxidants, nitric oxide, malondialdehyde, and saliva to evaluate cortisol. At the same time, an etogram and evaluation of mean daily gain and feed conversion were applied. The evaluated parameters on first day of the experiment did not vary between groups (P> 0.05). On the last day, neutrophil and neutrophil /lymphocyte ratios were higher in chain group piglets, as were salivary cortisol values (P< 0.05). Uric acid was higher in chain group and MDA in bottle group (P< 0.05). Environmental enrichment stimulated positive behaviors in piglets, where the rope stood out as the most attractive. On the other hand, chain had a negative effect on animal physiology, generating stress, as well as the bottle that induced lipid peroxidation and a lower weight gain in piglets.