Effect of short-term water restriction on oxidative and inflammatory status of sheep (Ovis aries) reared in Southern Italy

Water restriction (WR) may impair productive and reproductive performances in livestock. Our major aim was to assess physiological changes associated with a short-term WR in sheep reared in Southern Italy, in order to develop novel methods for evaluating/monitoring the biological implications of such environmental stress. Control animals received water ad libitum (24 h/day) throughout the experimental period. Treated animals were exposed to progressive water restriction (WR) (days 0-4: 12-6 h/day; days 4-8: 3 h/day), followed by a re-adaptation phase (days 9-10). Plasma concentrations of nitro-tyrosine (N-Tyr) and carbonyl (PC) derivatives were measured as markers of protein oxidation. Lipid hydroperoxides (LPOs) were titrated as index of lipid oxidation. Haptoglobin (Hpt) and cortisol were titrated as markers of systemic inflammation and endocrine stress, respectively. Polypeptide profiling of serum samples was performed by MALDI-TOF-MS analysis. Plasma N-Tyr concentration was higher in WR group at day 8 and 10, and significantly increased from day 4-8. Both PC and LPOs levels were higher in WR animals at each time point, and increased until day 8. The concentration of the inflammatory marker Hpt was higher in WR at day 4 and 8, and progressively increased until day 8. MALDI-TOF-MS ascertained decreased levels of apolipoprotein A-II (ApoA-II) and increased levels of platelet factor 4 (PF4) in WR animals at day 8. Taking into consideration the limitations due to the involvement of these redox status and inflammatory biomarkers in other stressing events, these results suggest that N-Tyr concentration might contribute to assess whether a condition of severe WR is occurring, while PC and LPOs may be used for identifying WR animals, and for evaluating the extent of deprivation. The concentration of Hpt, PF4 and ApoA-II might be used in combination for identifying dehydrated animals, and for monitoring the restoring of homeostasis.