Elaboration of an experimental model of the oxidative stress in weaned piglets

Visuels de Eric Royer et al., 67th Annual Meeting of the European Federation of Animal Science (EAAP), 29 août-02 septembre 2016, Belfast, Irlande, Royaume-Uni

An experimental model was established as tool for the study of the oxidative stress in weaning pigs. In two experiments, 360 weaned piglets were randomly allocated to eight groups in 2×2×2 factorial designs. In Exp.1, the factors were the sex, a vaccination at weaning against porcine circovirus type 2 (PCV2) or not, and phase 1 diets with NRC (2012) levels for vitamin E and selenium (SA) or extra supplementation in vitamin E, selenium yeast and superoxide dismutase-rich melon supplement (HA). In Exp.2, a double vaccination against PCV2 and porcine influenza, heat stress at d 9-10, 23 24 and 37-38 (36.5 °C over 6 h period) or controls, and SA or HA diets were applied. Blood samples were taken from 6 piglets per treatment at d 13, 28 and 40 in Exp.1 and d 13 and 40 in Exp.2. Serum haptoglobin, glutathione peroxidase activity (GPx), blood lipid peroxides and protein carbonyls were determined. Half-hemolysis time (HT50) of whole blood (WB) and red blood cells (RBC) exposed to a controlled free radical attack were determined. The HA supplementation increased HT50 of WB and RBC (P<0.02) in Exp.2, as well as HT50 of WB at d13 (interaction, P=0.04) and RBC of non-vaccinated pigs (interaction, P=0.05) in Exp.1. In Exp.2, GPx increased (P=0.01), whereas lipid peroxides (P=0.01) and protein carbonyls (P=0.05) decreased as a result of HA diet. Vaccinations increased haptoglobin in Exp.1 and 2, as well as lipid peroxides in Exp.2 (P=0.05). Moreover, the double vaccination decreased GPx activity for HA fed pigs at d 40 (interaction, P=0.05) in Exp.2, and protein carbonyls in Exp.1 and 2 (P<0.06).

Vaccination × heat stress × time interactions (P<0.05) were observed on HT50 values in Exp.2. At d 40, heat stress decreased WB (P=0.01) and RBC HT50 (P<0.01) for the vaccinated piglets, whereas such effects were not observed for the non-vaccinated piglets. In conclusion, a model based on heat stress and vaccination may be efficient to assess strategies limiting oxidative stress.