The Role of Zinc in Poultry Breeder and Hen Nutrition: an Update

Zinc (Zn) is an essential trace mineral in breeder hen diets and functions in diverse physiological processes, including reproduction, immunity, antioxidant ability, and epigenetic processes. In this paper, five main aspects of Zn nutrition in poultry breeder birds and hens, including semen quality, molting, egg production and egg quality, hatchability and embryonic development, and offspring performance, are reviewed. Zn deficiency in poultry breeder birds led to lower semen quality (reducing around 10% sperm motility) and egg production (lowering 3-10 g/day/bird egg mass) as well as poor offspring development and growth performance (increasing 9-10% weak chick ratio and 10% mortality of progeny). Adequate maternal or higher Zn supplementation was adopted not only to induce molting with a greater postmolt performance (rising 4-7% laying rate) but also to enhance progeny immune response and antioxidant ability via epigenetic mechanisms. Therefore, it is necessary to reevaluate the optimal Zn requirement for egg production as well as the embryonic development and offspring chick performance of breeder hens. In the last 10 years, greater attention has been focused on the effectiveness of organic Zn for improving the reproductive performance of breeders and progeny viability and immune status. In fact, organic Zn sources are not always beneficial to the above aspects. So far, it has been very important to know the exact mechanisms of greater bioavailability and the epigenetic role of organic Zn sources in the augmentation of immune status and antioxidant abilities in poultry breeder birds and offspring. Therefore, a comprehensive analysis of these key points will not only aid in maintaining the beneficial effects of Zn nutrition for breeders and their progeny under stable conditions but will also support birds under stressful conditions such as disease as well as provide a better understanding of the integrated nutrition of breeder-offspring.

Metal limitation and toxicity at the interface between host and pathogen

Metals are required cofactors for numerous fundamental processes that are essential to both pathogen and host. They are coordinated in enzymes responsible for DNA replication and transcription, relief from oxidative stress, and cellular respiration. However, excess transition metals can be toxic due to their ability to cause spontaneous, redox cycling and disrupt normal metabolic processes. Vertebrates have evolved intricate mechanisms to limit the availability of some crucial metals while concurrently flooding sites of infection with antimicrobial concentrations of other metals. To compete for limited metal within the host while simultaneously preventing metal toxicity, pathogens have developed a series of metal regulatory, acquisition, and efflux systems. This review will cover the mechanisms by which pathogenic bacteria recognize and respond to host-induced metal scarcity and toxicity.

Immune system and cardiac functions of progeny chicks from dams fed diets differing in zinc and manganese level and source

This research was conducted to evaluate immunity (experiments 1 to 3), cardiac function, and ascities resistance (experiment 4) of progeny chicks from broiler breeders fed diets differing in trace metal level and source. Broiler breeders received a control diet (75 mg of Zn and 83 mg of Mn added/kg of diet), the control diet supplemented with inorganic Zn (75 mg/kg of diet) and Mn (80 mg/kg of diet), the control diet supplemented with organic Zn (75 mg/kg of diet) and inorganic Mn (80 mg/kg of diet), or the control diet supplemented with organic Zn (75 mg/kg of diet) and Mn (80 mg/kg of diet) in experiments 1, 2, and 3. In experiment 4, the control diet and diet supplemented with organic sources of Zn and Mn were fed to broiler breeders. Immune organ weights, circulating granulocytes vs. agranulocytes, CD4 and CD8 positive T cells, cutaneous basophil hypersensitivity, and antibody titers to SRBC and breeder vaccinations were measured in progeny. Some supplemental mineral treatments increased (P < or = 0.05) cutaneous basophil hypersensitivity and relative bursa weight. All supplemental mineral treatments increased (P < or = 0.05) relative thymus weight. In experiment 4, electrocardiograph, pulse oximetry, heart rate, hematocrits, ventricle weights, and ascites incidence were measured in progeny reared in a cold-stress environment. The supplemental organic minerals increased (P < or = 0.05) left ventricle plus septum and total ventricular weights. Although progeny ascites incidence did not differ between breeder mineral treatments, breeders fed supplemental Zn and Mn sired progeny with improved cardiac functional capacity and some improvements in immunity.