Zinc in Poultry Feed Trace

¶ … Zinc in Poultry Feed

Trace minerals, such as zinc, are critical nutrients in the diet of poultry needed for growth of poultry as well as for development of bone, feathering, enzyme structure, function, and appetite. (LSU Agricenter Report, 2007) the LSU Agricenter reports research conducted in order to make examination of the impacts of removal of zinc from the diet of poultry. Study findings state that the removal of zinc from the diets of chickens negatively affected growth performance and bone strength of the chickens. In the case where the chickens receive zinc in their diet and then zinc is later removed these negative results were not noted which indicates that zinc is needed in the earlier developmental stages of young chicks but not necessarily required in the ongoing diet of older chickens.

SYMPTOMS of ZINC DEFICIENCY

The work of Wang, Fosmire, Gay and Leach (2002) states symptoms of zinc deficiency in chickens to include: "...significantly inhibited chondrocyte proliferation, promoted cell differentiation and induced cell apoptosis in the growth plate. These effects were manifested primarily in areas remote from the blood supply." (p. 211) the work of Kienholz, Turk, Sunde and Hoekstra stats that exclusion of zinc from the diet of hens resulted in a failure for the hens to gain weight normally and hatchlings were weak, unable to stand, eat or drink. Further, the hatched chicks had respiratory problems.

The work of Kidd, Qureshi, Ferket, and Thomas entitled: "Turkey Hen Zinc Source Affects Progeny Immunity and Disease Resistance" published in the Applied Poultry Science Journal in 2000 state that "Progeny immunocompetence and disease resistance from turkey hens receiving dietary supplemental zinc was investigated. Twelve hens received a diet that contained 82 mg/kg Zn. Diets were supplemented with 40 mg/kg Zn sulfate (ZnSO4) or 40 mg/kg Zn methionine (ZnM) and analyzed to ctain 122 and 118 mg/kg total Zn, respectively (six replications per treatment)." Hens that received the supplemental ZnM had heavier bodyweight in their chicks however no differences were noted in the liver, heart, spleen and bone weights. (Kidd, Qureshi, Ferket, and Thomas, 2000; p. 418) Hens and chicks that received supplemental ZnM were noted to have "significantly higher nonspecific cellular immunity..." (Kidd, Qureshi, Ferket, and Thomas, 2000; p.421).

II. ZINC REQUIREMENTS DURING LIFE of CHICKEN

The work of Kidd, Qureshi, Ferket and Thomas (2000) state that zinc requirements for white egg-laying hens at 0 to six weeks is 40.0 mg; at 6 to 12 weeks is 35.0 mg; 12 to 18 weeks is 35.0 mg; 18 weeks to first laying of eggs is 35.0 mg. The nutritional requirement of zinc for brown egg-laying hens from 0 to six weeks is 38.0 mg; from 6 to 12 weeks the nutritional requirement of zinc is 33.0 mg; from 12 to 18 weeks the nutritional requirement of zinc is 33.0 mg and from 18 weeks to the first laying of eggs the nutritional requirement of zinc is 33.0 mg. It is related that the amount of zinc required per hen daily for white-egg breeders is 29 kg of zinc per 100 grams of feed. (p. 423)

III. STUDIES of ZINC in CHICKEN DIET

The work of Hudson, et. Al. (2003) entitled: "Effect of Broiler Breeder Age and Zinc Source in Boiler Breeder Hen Diets on Progeny Characteristics at Hatching" published in the Applied Poultry Research Journal states that: "Chick quality can impact the incidence of morbidity and mortality of broilers during the first week of production." (2003) the experiment reported made an evaluation of the effects of "broiler breeder age, dietary zinc source, and their interaction on physiological characteristics of chicks at hatching." (Hudson, et al., 2003; p. 1) the hens in this study were given one of three diets from the time of hatch until they were 65 weeks old. All diets are stated to have consisted of: "160ppm supplemental zinc from inorganic AnSO4, Availa®Zn zinc-amino acid complex (ZnAA) or a mixture of ZnAA and ZnSO4." (Hudson, et al. 2003) Measurements of incubation time, relative organ weights and carbohydrate status were made in chicks from hens at 29, 41, 53, and 65 weeks of age." (Hudson, et al., 2003; p.1)

Hudson et al. (2003) states additionally that: "Variation of hatching time was not influenced by hen age, but mean incubation time decreased from 29 to 53 wk of age and subsequently increased from 53 to 65 wk. Seasonal temperature changes may have caused confounding effects on incubation time. Chick heart glycogen declined as hens aged, and liver lactate was lowest in progeny from 65 wk-old hens. Relative yolk sac weight and relative heart weight were lowest in progeny from 29 wk-old hens. These data indicate that underdevelopment of supply organs may limit the performance of chicks from young hens. Supplemental zinc source in breeder hen diets did not influence chick physiology at hatching." (p.1)