Cocoa husks fed to lactating dairy ewes affect milk fatty acid profile and oxidative status of blood and milk

Abstract

The objective of this study was to evaluate the effect of cocoa husks (CH) containing theobromine on milk fatty acids (FA) and on milk and blood oxidative status in dairy ewes. The experiment was carried out with 24 dairy ewes and it lasted 8 weeks with 3 weeks of adaptation period and 5 weeks of experimental period. Animals were divided in three homogeneous groups and all ewes were fed with the same basal diet, composed of a total mix ration (TMR). The first group (CON) was fed with the TMR and a supplementation of 100 g/d per head of soybean hulls, while the second (CH50) and the third groups (CH100) were fed with the TMR and a supplementation of 50 and 100 g/d per head of CH, respectively. Blood samples were analyzed for the activities of superoxide dismutase (SOD), glutathione transferase (GSTS), glutathione reductase (GR) and glutathione peroxidase (GPx), while milk samples were analyzed for SOD, GR and lactoperoxidase (LPO). Total antioxidant capacity and oxidative stress biomarkers in blood and milk samples were determined. Orthogonal polynomial contrasts (linear and quadratic) were used to investigate the effect of the diet on the variables. The C16:0 and MCFA (medium-chain fatty acids) decreased, whereas C18:0 and LCFA (long-chain fatty acids) increased quadratically with the dose of CH. The supplementation of CH decreased linearly the OBCFA (branched-chain fatty acid). Regarding antioxidant results, mean protein carbonyls (PC) decreased linearly and SOD activity tended to increase linearly in blood with increasing CH dose. Meanwhile, antioxidant analysis of milk samples showed that CH supplementation increased quadratically the LPO and tended to decrease quadratically the malondialdehyde level (MDA). In conclusion, the addition of CH as supplement to the diet of ewes could modify the milk FA profile and could improve antioxidant capacity of blood and milk.