Selko® AOmix supports the antioxidant status of broilers under challenging conditions

Conclusion

To optimise oxidative status in broilers under challenging environmental circumstances, high levels of antioxidants are required to counteract the negative effects of reactive oxygen species. The addition of either 15 mg/kg vitamin E or 15 mg/kg Selko AOmix to broiler diets containing 10 mg/kg vitamin E diminished an increase in plasma malondialdehyde (MDA) levels (a marker for oxidative status) that may occur in animals in conditions where heat challenge is expected. In breast muscle, both Selko AOmix and vitamin E supplementation prevented an increase in MDA levels in these situations. Therefore, Selko AOmix is a suitable alternative for vitamin E for supporting the antioxidant status in broilers and influencing meat quality.

Vitamin E is a regular feed component of poultry diets. Vitamin E neutralises reactive oxygen species (ROS)which could otherwise damage DNA, proteins and membranes. However, the efficacy of vitamin E decreases quickly when dosed well above the National Research Council (NRC) recommended levels, and a multi-pronged approach using polyphenols can be more effective. The efficacy of vitamin E and Selko® AOmix was compared in challenged broilers. When feeding a diet with only 10 mg/kg vitamin E, malondialdehyde (MDA), a marker for oxidative status, increased in blood plasma and in breast muscle tissue after the broilers were housed in heat challenged conditions. The increase of MDA levels was diminished in blood plasma and prevented in breast muscle by adding vitamin E and by adding Selko AOmix up to a total antioxidant level of 25 mg/kg. No difference in MDA levels could be determined between the use of vitamin E and that of Selko AOmix. These data show that increasing the level of antioxidants to concentrations higher than 10mg/kg has a protective effect on oxidative balance and that vitamin E can be partly replaced by Selko AOmix for this purpose.

Oxidative challenge forms a threat for the poultry industry

Environmental challenged conditions can influence oxidative status in broilers on a cellular level. Cells use oxygen to generate metabolic production of reactive oxygen species (ROS). During times of environmental challenged conditions (e.g., heat exposure, disease, or poor-quality diets), ROS levels can increase dramatically, which damages cell structures. A healthy oxidative balance is one of the key factors for supporting good production, growth, hatchability and general welfare/ health/ survivability. Above all it supports meat and egg quality.

Optimal antioxidant status helps to limit the damaging effects of ROS

Oxidative status is in fact an imbalance between the manifestation of reactive oxygen species and the ability of the body to detoxify the ROS. Antioxidants are used to counteract the effect of ROS. In poultry feed, vitamin E is used as an antioxidant. However, vitamin E has poor bioavailability and its efficacy diminishes quickly above NRC requirements. Hence, it may partly be replaced by other antioxidative substances. Selko AOmix has been developed to partly replace vitamin E in poultry diets.

Trials results show: NRC-recommended levels of vitamin E in poultry diets are insufficient to prevent oxidative damage under challenging conditions

In a study, broilers fed a diet containing 10 mg/kg vitamin E were exposed to an environmental challenge for 5 hours at a temperature of 35˚C and lipid peroxidation by ROS, and as such is assayed in vivo as a bio-marker of oxidative status. MDA levels significantly increased in blood plasma and breast muscle of the environmentally challenged broilers fed a diet containing 10 mg/kg vitamin E, which indicates that NRC recommended levels of vitamin E in poultry diets are insufficient to prevent oxidative damage during a challenge.

Selko AOmix supports an optimal antioxidant status in poultry

Supplementation above the NRC recommendation to 25 mg/ kg with either vitamin E or with Selko AOmix had no effect on MDA in non-challenged birds (data not shown). However, in challenged conditions, it diminished the increase in plasma MDA levels. Selko AOmix and vitamin E yielded the same result (Figure 1).

Figure 1. Effect of vitamin E and Selko® AOmix on oxidative stress levels in broilers under challenged conditions. MDA levels measured in plasma.

Selko AOmix positively influences meat quality even in challenge conditions

Supplementation to 25 mg/kg prevented an increase in MDA levels in breast muscle in challenged broilers. Selko AOmix and vitamin E yielded the same result (Figure 2).

Figure 2. Effect of vitamin E and Selko® AOmix on oxidative challenge levels in broilers under challenged conditions. MDA levels measured in meat.