In egg production longer laying cycles can help to cut costs, so they are a promising solution in a tough economic climate. Plus, they can reduce the environmental impact of egg production. Therefore, there is an increasing focus on improving laying persistence and egg quality at the end of the laying cycle. However, due to increasingly intensive metabolism for egg formation, laying hens are more susceptible to diseases, which requires a shift in breeding and nutrition towards greater resilience of birds to improve laying persistence for longer laying cycles.
There is a fast decline in egg production after the hens reach 480 d of age leading to reduced commercial value of laying hens. Understanding the mechanisms of the deterioration of the laying performance can help to slow down the process. The ovary and the liver are key organs involved in egg production of the laying hen, which is why knowing how to support them effectively by nutritional means can make a difference to laying persistence.
Oxidative stress in aging organs
Ovarian aging is one of the highest risk factors that lead to the decline of ovarian functions and hence a reduction in egg production. Studies have shown that oxidative stress plays a driving role in ovarian aging. The antioxidant status of the ovary decreases with age (Figure 2) as a result of a reduction in antioxidant enzymes and antioxidants in the hen’s own defense mechanisms. Oxidative stress is initiated by the gradual accumulation of reactive oxygen species (ROS) in the ovary and a reduction of the antioxidative capacity during the aging process. This will be exacerbated through stressors, such as heat, mycotoxins, endotoxins and others, which increase the production of ROS in the hen on a cellular level. A growing body of evidence suggests that oxidative stress is involved in most of commercially relevant stresses in poultry production. Oxidative stress is defined as an imbalance between production of ROS and their elimination by protective mechanisms. This imbalance leads to damage of important biomolecules and cells, with potential impact on the whole organism. It can also lead to inflammatory responses which can affect energy efficiency of the laying hen.
Age-related changes in the antioxidative capacity of the hen’s liver, is an important factor that influences liver function. Studies have demonstrated that the total antioxidant capacity of the liver declines as the hen ages (Figure 2) and this has also been linked to a decrease in egg production and in the ability of yolk precursor formation.
Feeding for resilience in egg production
To extend the laying cycle of commercial flocks, long-term maintenance of organs involved in producing eggs is required. Feeding for antioxidative capacity in laying hens has been shown to retard the antioxidant decline of aging ovaries and can thus help to maintain functioning ovaries for longer. It is also known to maintain a healthy liver for longer. However, feeding to improve the adaptive capacity of birds to stressors helps to minimize stress reactions, such as oxidative stress, as well as inflammatory responses and reduced feed intake, which can further increase resilience in birds and reduce the potential for stressors to diminish the chances for producers to successfully extend the laying period. Animal resilience has been defined as “the capacity of the animal to be minimally affected by challenges or to rapidly return to the state pertained before exposure to a challenge.
The gut agility concept in Anco FIT Poultry was specifically developed to increase the capacity of the bird to adapt to challenges more efficiently and to reduces stress reactions that would otherwise reduce the hens performance and potential to sustain longer laying cycles. A trial carried out in a commercial laying hen flock in Brazil, demonstrates how Anco FIT Poultry improves the resilience of birds to stressors compared to birds on a control diet (Figure 3). The impact of stressors was smaller on egg production and birds recovered quicker from stressors leading to greater laying persistency and more eggs produced per hen over the trial period.
Published in International Poultry Production by Gwendolyn Jones