From curvy hens to the laying curve. The influence of dietary strategies on body composition and laying persistency in hens

With a growing world population, eggs are an important and affordable nutrient source to nourish the world. The lifetime egg production capacity of laying hens has increased tremendously, with production targets currently extending to 600 eggs at 120 weeks of age. To sustain this laying persistency, nutrition is crucial to support the hen and provide the right nutrients for egg formation. This thesis aimed to understand how dietary energy and amino acids intake, from rearing to laying, influence body composition and metabolic processes, to support long-term egg production. Results showed that higher-density diets during rearing increased body weight and improved laying persistency. Moreover, during the laying phase, reducing dietary energy, thereby increasing nutrient intake, enhanced laying persistency. Lastly, a higher contribution of lipids relative to starch improved liver health. Key physiological drivers for laying persistency were identified, including body composition, liver function, and specific hormonal processes.