A large number of articles highlight the importance of antioxidants in animal feed. Its use is justified in order to avoid the appearance of “oxidative stress”, which can cause losses in the productive performance, as well as losses in both nutritional and organoleptic quality of the products derived from them.
What is oxidative stress?
Oxidative stress is the imbalance between the endogenous generation of free radicals and the antioxidant defense system of the organism (Halliwell and Gutteridge, 1999).
There are a number of endogenous antioxidants, produced by the body itself, to fight against these free radicals, but at a certain time it is necessary to add exogenous antioxidants in order to maintain the physiological balance between an excessive production of free radicals and an adequate amount of antioxidants in the body.
Therefore, to diminish these negative effects on the organism and the meat, several studies have confirmed the efficacy of antioxidants both “in vivo” and post-mortem.
In this article we will evaluate the consequences of the use of antioxidants, both during the animal’s life and after its slaughter, as well as in the products obtained.
It is important to understand when an extra addition of exogenous antioxidants is necessary in the diet, making it crucial to identify the factors that cause an imbalance in the organism of birds, among which we can highlight:
- Incorrect temperatures on the farm, in addition to high levels of ammonia and carbon dioxide due to poor ventilation.
- Situations that cause stress to the animal
- Toxics or heavy metals, some medications, even excesses of Vitamin A
- Feeding with oxidized fats.
Effects of Antioxidants in Vivo:
During the life of the animal, there are several factors that could affect its final production, such as pathological, nutritional, physiological or environmental causes that cause oxidative stress and reduce the performance of animals.
It is considered that the components of the feeding will have a modulating effect in the maintenance of this balance. As indicated by a large number of studies (Fellenberg and Speisky, 2006, Salami et al., 2015), which highlight the importance of the use of antioxidants in broilers and poultry, as well as in breeding animals.
Antioxidants and Fertility:
Sperm have a high amount of polyunsaturated fatty acids, which will be very susceptible to oxidative stress, so an antioxidant protection will be essential for motility and fertility.
Therefore, diets rich in antioxidants would help increase the level of antioxidants and thus improve motility and fertility.
The tissues of the embryo have a large amount of polyunsaturated fatty acids, hence their ability to oxidize and their need for antioxidant protection. Many of them are released by the mother, during egg laying, and thanks to the food provided, the amount of antioxidants such as Vitamin E or Selenium may be higher. Others will be synthesized by the embryo’s own tissues.
The amount of lipids and the concentration of antioxidants will determine the vulnerability of the embryo to free radicals.
Diets with supplemented by antioxidants would help to increase the concentrations in the chicken and decrease its susceptibility to lipid peroxidation
Effects of Postmortem Antioxidants:
In addition to these “in vivo” effects, antioxidants can also have postmortem effects, in the meat obtained from the animal as well as in the egg. These points are developed below:
Effects on Meat
Among the improvements in the quality of the meat due to an increase in in vivo antioxidant supplementation we could highlight:
– Improvements in color and oxidative stability of lipids.
– Reduction of odor and rancid taste, both raw and cooked.
– Increase of the CRA (Water retention capacity) “prevention of fluid losses”
Effects on the Egg
At present, the diet provided to birds is rich in n-3 fatty acids, since they are considered to be of great importance for growth, development, as well as being beneficial for human health.
By increasing these fatty acids in the diet, the amount of fatty acids in the egg also increases, which will cause it to deteriorate faster. In order to reduce this deterioration, it was observed that antioxidants, especially Vitamin E, prevented the degradation of fatty acid even after several days of storage.
We can conclude that lipid oxidation in poultry production will later affect the quality and deterioration of products destined for human consumption. In order to reduce these losses in the product, a series of antioxidants suitable for each stage must be used, taking into account the different factors that catalyze the start of the same.