S.Y. Park

Review on the role of dietary zinc in poultry nutrition, immunity, and reproduction

Zinc is an important nutrient in animal metabolism. In poultry, zinc serves not only as a nutrient but can also be used as a dietary supplement to manipulate the reproductive system of the bird. This article summarizes the general biochemistry, physiology, and nutritional aspects of zinc metabolism to provide a brief overview on what is known regarding zinc. The potential role of zinc in poultry immune response, Salmonella infection, and molting are emphasized.

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

The United States (U.S.) poultry industry continues to implement induced moulting to extend egg production in commercial laying flocks. Achieving an optimal moult requires dietary manipulation to cause a complete regression of the reproductive organs and cessation of egg production. This is followed by rejuvenation and initiation of an additional egg laying cycle. Currently feed withdrawal is the primary means to initiate moult and is regarded as an optimal approach for achieving post-moult performance. However, removal of feed can lead to potential physiological stress in laying hens as well as an increased susceptibility to Salmonella enteritidis colonization and invasion. To retain the ecological benefits of induced moult will require development, testing and implementation of alternative dietary approaches that minimizes these problems and increase the egg production and egg quality benefits associated with the additional egg laying cycles. Strategies for accomplishing this are discussed.

Environmental Dissemination of Foodborne Salmonella in Preharvest Poultry Production: Reservoirs, Critical Factors, and Research Strategies

The impact of potential pathogenic foodborne Salmonella spp. in poultry production environments is of paramount importance, considering its implications for human health. Most of what is known about this organism under these environmental conditions is based on indirect evidence. The overall focus of this review is on the biology of potentially pathogenic foodborne Salmonella spp. in poultry environments. This is not just because of the implications regarding pathogenic Salmonella spp. for poultry production and food safety but because Salmonella spp. behavior may serve as a model for understanding general bacterial pathogen persistence in animal agricultural environments. This will help meet a long-term need to develop a comprehensive ecological picture of the contamination potential, growth, survival, and genetic stability of pathogens in poultry and other animal production environments. This will in turn lead to a better understanding of the environmental and health impacts of foodborne Salmonella spp. dissemination in animal production environments.

Using a feed-grade zinc propionate to achieve molt induction in laying hens and retain postmolt egg production and quality.

A commercial-feed-grade form of zinc propionate was examined as a potential feed amendment at a concentration of 1% zinc to induce molt in 90-wk-old hens. Dietary treatments consisted, of 4 treatment groups of 28 birds each randomly assigned to either (1) molted conventionally by feed withdrawal, (2) 1% zinc as Zn acetate, (3) 1% zinc as Zn propionate, or (4) nonmolted control for 9 d. Ovary weights of hens fed Zn acetate or Zn propionate were not significantly different from each other, but hens fed Zn acetate or Zn propionate were significantly (p<0.05) lighter than the ovary weight of nonmolted control hens. Zinc concentrations in the kidney and liver were significantly (p<0.05) increased in both Zn acetate- and Zn propionate-molted hens when compared to either nonmolted control-fed hens or feed-withdrawal molted hens. Over the entire 3-mo postmolt period, there were no significant differences in interior or exterior egg qualities among the four treatments Egg production of hens fed Zn acetate was significantly lower than feed-withdrawal hens, Zn propionate-fed hens, or nonmolted control hens (p<0.05). The data of the current study demonstrated that feeding a feed grade of Zn propionate (1% Zn)-supplemented diet can induce molt and retain postmolt egg quality and production comparable to hens molted by feed withdrawal.

The combination of zinc compounds and acidic pH limits aerobic growth of a Salmonella typhimurium poultry marker strain in rich and minimal media.

Abstract The objective of the present study was to examine the combined effects of zinc compounds with different acidic pH levels on the aerobic growth of a S. typhimurium poultry isolate in either rich or minimal media. When overall main effects of pH levels of medium or concentrations of Zn compounds were compared, growth rates of the S. typhimurium poultry isolate were significantly ( p < 0.05) decreased by stepwise increase of pH levels of medium (pH 4, 5, 6, and 7) or concentrations (0.67, 3.35, and 6.03%) of Zn compounds (Zn acetate and Zn sulfate). In general growth rates of S. typhimurium poultry isolate appeared to be more reduced by Zn acetate than by Zn sulfate and more reduced in minimal media compared to rich media.