Estrés oxidativo y actividad antioxidante en leche de vacas con mastitis subclínica

Abstract

Mastitis is a expensive disease for dairy farming, the highest incidence occurs in the peripartum. The objective of this study was to determine the oxidative stress (OE) and antioxidant activity (AA) in the milk of cows with mastitis. Crossbred cows Holstein x Carora (n=30) were evaluated in the first 150 days of lactation, belonging to a commercial exploitation of Lara (Venezuela), divided into two groups of 15 animals each: control and one with subclinical mastitis (SM). Two milk samples were collected and stored in cryovials in liquid nitrogen. As OE indicators conjugated dienes (CD) were quantified using the Wallin and malondialdehyde (MDA) method by TBARS. The AA was evaluated by enzyme glutathione peroxidase (GSHPx) and glutathione (GSH) using a commercial kit. Data were analyzed by the "t" test. CD increased in the group with SM (1.41±0.12 nmol/mg protein) compared to the control group (0.59±0.08; p < 0.001), as well as MDA (0.38±0.02 nmol/mg protein) compared to control (0.29±0.02, p < 0.001) value. GSH-Px activity was elevated in the group with SM (40.75±5.09 mmol/min/ mL) compared with the control group (27.65±2.18, p < 0.05). GSH concentration was increased in the group with SM (273.71±37.51 μmol/L) compared to the control group (150.00±21.17; p < 0.05). It is concluded that subclinical mastitis in milk induces a state of OE, accompanied with an increase in antioxidant activity. These results support antioxidant supplementation during the peripartum period bovine.