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

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.

Supplementation of poultry feeds with dietary zinc and other minerals and compounds to mitigate nitrogen emissions--a review

One of the environmental challenges that the poultry industry has been faced with is ammonia emission from manure. One way to reduce nitrogen excretion and emissions is supplementing dietary trace minerals to inhibit the activity of microbial uricase, a key enzyme converting nitrogen compounds in the manure into ammonia. Several dietary minerals are commercially available as economic alternatives for reducing ammonia emissions in poultry. In this review, we discuss different mineral elements including zinc as feed amendment minerals that could be used to reduce ammonia emission. Issues discussed include potential for inhibiting microbial uricase, dietary supplementation levels, growth performance, toxicity, their influence on manure nitrogen emission, and potential mineral accumulation in soil. In addition, we discuss other minerals and compounds that have the potential to reduce ammonia volatilization by inhibiting microbial uricase and growth of uric acid-utilizing microorganisms.

The influence of a fructooligosaccharide prebiotic combined with alfalfa molt diets on the gastrointestinal tract fermentation, Salmonella enteritidis infection, and intestinal shedding in laying hens

Molting is a natural process, which birds undergo to rejuvenate their reproductive organs. The US poultry egg production industry has used feed withdrawal to effectively induce molt; however, susceptibility of Salmonella Enteritidis has encouraged the development of alternative methods. Previous research conducted in our laboratory showed that alfalfa is effective at molt induction and provides equivalent postmolt production numbers and quality when compared with feed withdrawal. In the attempt to further increase the efficacy of alfalfa molt diet and decrease the chicken susceptibility to Salmonella Enteritidis during molt, fructooligosaccharide (FOS) was added to a combination of 90% alfalfa and 10% layer ration in 2 levels (0.750 and 0.375%). Ovary and liver colonization by Salmonella Enteritidis in 3 and 2 of the 4 trials, respectively, were reduced (P <or= 0.05) in hens fed FOS-containing diets compared with hens subjected to feed withdrawal. Significant decreases in ce-cal Salmonella Enteritidis counts were also observed in 2 of the 4 trials. In 3 of the 4 trials, the same diets did not affect (P > 0.05) the production of cecal total volatile fatty acids when compared with hens undergoing feed withdrawal. However, in all 3 alfalfa molt diets, the concentrations of lactic acid were greater (P <or= 0.05) than hens with feed withdrawal, but no differences (P > 0.05) were observed among hens fed alfalfa combined with FOS and hens fed alfalfa/layer ration without FOS. Overall, given the similarities between hens fed 0.750% FOS (H) and 0.375% FOS (L), molt diets combined with the lower level of FOS should be sufficient.

Immunological cell and serum metabolite response of 60-week-old commercial laying hens to an alfalfa meal molt diet

The practice of induced molting involves the restriction of light, feed removal and optionally water for 5-14 days. However, there is growing concern regarding feed removal and animal welfare issues. With this in mind, alternative diets have been developed to produce similar molting effects as that of feed deprivation. Alfalfa, which largely consists of insoluble fiber, can be used as a molting diet. In this study, heterophil and lymphocyte counts, serum chemistry, and organ weight parameters were evaluated in hens that were deprived of feed or fed alfalfa during a nine day induced molt. Full-fed hens were used as the control. Blood serum parameters assessed included calcium, magnesium, glucose, total protein, ketone bodies, uric acid, and cholesterol. White blood cells were counted and categorized by cell type. On the ninth day of the trial, the hens were euthanized and the liver, spleen, heart, intestine, pancreas, ovary, oviduct, and kidney were collected and weighed. On day 8 birds molted with alfalfa or by feed deprivation had significantly higher (P<0.05) levels of ketone bodies and cholesterol and lower levels of calcium, and magnesium compared to the full-fed hens while birds molted by feed deprivation exhibited significantly lower levels of uric acid. Birds molted by both methods exhibited significant reductions in ovary, oviduct, liver and pancreas weights and increased spleen weights when compared to the non-molted hens. On days 0, 2, and 6 there were no significant differences (P>0.05) in either heterophil or lymphocyte percentages. However, heterophil percentages were higher in feed withdrawal birds than full-fed birds on day 4 but lymphocyte percentages were higher in full-fed birds compared to feed withdrawal birds. On day 8 of the induced molt lymphocyte percentages were higher from full-fed birds when compared to feed withdrawal birds but no significant differences were detectable for heterophil percentages. Based on reproductive organ weight loss and changes in serum and immunological responses of birds during molt, it appears that alfalfa meal can be an effective molt induction alternative.