Alleviation of oxidative stress by using olive pomace in crossbred (brown swiss X baladi)‎ calves under hot environmental conditions

الملخص EN

Ten female crossbred (Brown Swiss X Baladi ) calves, 8 – 10 months old with average live body weight of 112 kg at the beginning of experimental period were used to investigate the effect of olive pomace (OP) supplementation which contains phenolic compounds on oxidant and antioxidant agents and some blood constituents, and its relation with growth performance in heat stressed calves.

The animals were maintained under hot summer environmental conditions, where, ambient temperature and relative humidity averaged 37.48°C ± 0.32 and 64.58 % ± 0.77, (equivalent to THI 91) during day, and 28.38 °C ± 0.22 and 78.23 % ± 0.69, (equivalent to THI 80) during night, respectively.

The animals were divided into two equal groups (5 calves each).

The first group )control( received 0 % OP of the concentrate mixture, while, the second group )treated) received 15 % OP of the concentrate mixture, for two months.

Body weight of calves was recorded twice at the beginning and at the end of experimental period, and daily gain was calculated for each animal.

Blood samples were taken from each animal at the end of experimental period to determine antioxidant and oxidant indices, some blood constituents and T3 concentration.

Our results showed that supplementation of OP significantly increased antioxidant status including catalase enzyme activity, total antioxidant capacity, uric acid as a non-enzymatic antioxidant and copper as a specific antioxidant protecting macromolecules.

Moreover, OP significantly reduced serum malondialdehyde as a lipid peroxidation marker, iron concentration which act as a pro-oxidant, lipids profile including total cholesterol, low density lipoprotein (LDL – cholesterol), very low density lipoprotein (VLDL – cholesterol), triglycerides and phospholipids.

Also, OP caused a significant decrease in serum creatinine and urea-N concentrations as well as AST activity.

However, OP significantly elevated T3 level, and improved feed efficiency and daily gain.

It can be concluded that supplementation of OP at the level of 15 % of concentrate mixture under Egyptian hot summer environmental conditions reduced the negative effect of oxidative stress as shown by significantly improving antioxidant status, most blood constituents and T3 level as well as growth performance in growing crossbred calves.