Fending against pathogens, the role of a strong immune system for laying hens and egg consumers

Biosecurity is a major consideration for egg farmers across the world, and can be regarded as the ecosystem of measures capable of preventing the spread of harmful organisms to animals to reduce the risk of transmission of infectious diseases. Strong biosecurity requires all preventative measures to work collaboratively, from vaccines to physical barriers, hygiene practices, personal protective equipment (PPE) and bio-monitoring. It is essential that all elements are working in sync, with no weak links, to maximize production and minimize casualties.

An important link to biosecurity and the spread of virus, which can sometimes be forgotten, is the performance of the immune system. It is the first barrier of defense against pathogens, both bacterial and viral origin. A good layer immune system will ensure the animal has a strong response to vaccines and will help to reduce the severity of infections. In a recent paper (1) the importance of nutritional status on the process of protecting against viral infections was highlighted.

Vitamins A, B6, B12, C, D, E and folate; trace elements like zinc, iron, selenium, magnesium and copper and Omega 3 fatty acids, are all important in supporting an optimal functioning of the hen’s immune system. For instance, vitamin A is known to increase protection against Newcastle disease by increasing the body titer. While vitamin D is known to protect hens from immunological stress (2), it also reduces the susceptibility of egg yolk oxidation, thus improving the storage time of eggs. In addition, vitamin E has a modulatory effect on the immune system via the activation of macrophages and production of antibodies, necessary for the prevention and resistance against various diseases (3). As a bonus to strengthening the immune system, providing optimal nutrition also enables the hen to be less prone to bone deformities (osteoporosis) and helps to enhance the egg shell quality.

Providing optimum nutrition to laying hens is essential not only in boosting and maintaining the immunity of the layer, but also in protecting nutritional value of the eggs for consumers. Eggs are considered to be one of “nature’s first foods” with evidence mounting about the benefits of eggs for child nutrition and potential benefits for women during pregnancy and birth outcomes (4). The unique egg matrix of macronutrients, micronutrients, and immune factors, means eggs contain the majority of the essential nutrients required by the body, promoting growth, and potentially also helping child development (4). As is explained by Lutter et al., in their paper on the ‘potential of a simple egg to improve maternal and child nutrition’.

It is also possible to bolster the already impressive nutritional value of the egg, by enhancing with DHA, Omega 3, Vitamin E, D and folate. In addition, eggs may also provide the human body with nutrients and other immune factors in compounds that are more readily absorbed and metabolized, in comparison to single nutrient supplements (4). These are all important elements in the process of boosting the immune system of the consumer, but also the laying hen.