Antioxidant requirements for aged hens
As a hen ages, her egg production naturally diminishes on average. Egg production will often still vary by season, with the older hen being more prolific in the spring and summer and less so in the autumn and winter as daylength shortens. Egg size will also tend to increase with age, if all other factors remain equal. It is also more common for egg shell issues to become more prevalent as the hen ages. Deterioration in egg shell quality such as increased microcracks or thin shells, can result in an increased risk of egg breakage (in the oviduct and in the nest) and of bacterial contamination entering the egg. If the egg breaks in the oviduct, this can result in delayed egg laying or create a blockage, which can potentially predispose to salpingitis and even egg bind, both of which can be life threatening to the hen
These changes are associated with reduced hormonal and liver function in aged hens, in addition to reduced synthesis of Vitamin D metabolites, age related changes in the oviduct and poor digestive function. The latter can result from repeated challenges to the intestinal stability from altered feed quality, toxins and other stresses. Some of these stresses can impact on the antioxidant ability of the hen. This ability is an important factor for hen health and egg quality. Maintaining the antioxidant status of the hen can help stabilise the gut, maintain an effective immune system and thus reduce the impacts of aging.
The egg yolk and whites are predominantly comprised of lipoproteins and proteins. The liver is the main site of fat metabolism in the hen. Fatty liver syndrome, which is characterised by increased lipid accumulation in the liver tissues is associated with decreased egg production and occurs more commonly in aged hens.
Geriatric hens can benefit from good management of bodyweight, proactive control of parasitic diseases, the use of products to support liver function and that confer antioxidant protection in addition to ensuring satisfactory levels of vitamin D metabolites.
The liver is a vital organ that is involved in a wide range of functions including the metabolism of fat, carbohydrate, protein, vitamins and minerals, removal of waste products and detoxification. The liver is the main storage site of fat-soluble vitamins (A, D, K and E) as well as vitamin B12, glycogen, some minerals (Fe and Cu) and is also involved in the activation of vitamin D. The liver is the main site of phagocytosis by Kupffer cells, which destroy aged blood cells and pathogens that may enter via the hepatic portal blood.
