|Buhr, Richard - Jeff|
Submitted to: Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2003
Publication Date: 1/1/2004
Citation: Hudson, B.P., Farichild, B.D., Wilson, J.L., Dozier, W.A., Buhr, R.J. 2004. Effect of broiler breeder age and zinc source in broiler breeder hen diets on progeny characteristics at hatching. Applied Poultry Research. 3(1):55-64. Interpretive Summary: Chick quality at hatch can impact the livability of broiler chicks during the first weeks of life. Assessments of chick quality at hatch are made primarily by subjective observations with few actual measured values. Obtaining a better understanding of how broiler breeder hen age and zinc intake may influence physiology of their chicks may also enable certain actions to be taken to improve chick quality. This experiment evaluated the effects of broiler breeder age (29, 41, 53 and 65 weeks) and dietary zinc source on physiological characteristics of chicks at hatching. Breeder hens were provided one of three diets, containing 160 ppm supplemental zinc from inorganic, or an zinc-amino acid complex, or a mixture of the two. Relative organ weights and carbohydrate status (glycogen conversion to glucose and to lactate) were measured in chicks euthanized on the day of hatch. Chick heart glycogen and liver lactate declined as hens aged to 65 weeks of age indicating rapid lactate recycling to glucose. Relative chick, yolk sac, and heart weight were lowest in chicks from 29 week-old hens. These data indicate that underdevelopment of heart and yolk sac may explain the limited performance of chicks from younger hens. Supplemental zinc source in breeder hen diets did not measurably influence the chick parameters evaluated.
Technical Abstract: Chick quality can impact the incidence of morbidity and mortality of broilers during the first wk of production. Assessments of chick quality are made primarily by subjective observations with few quantitative measurements. Given a better understanding of how broiler breeder hen age and nutrient intake may influence physiology of their progeny, certain actions can be taken to improve chick quality. This experiment evaluated the effects of broiler breeder age, dietary zinc source, and their interaction on physiological characteristics of chicks at hatching. Caged broiler breeder hens were provided one of three diets from hatch through 65 wk of age. All experimental diets consisted of 160 ppm supplemental zinc from inorganic ZnSO4, Availa®Zn zinc-amino acid complex (ZnAA) or a mixture of ZnAA and ZnSO4 (ZnAA + ZnSO4, 80 ppm zinc from each). Incubation time, relative organ weights and carbohydrate status were measured in chicks from hens at 29, 41, 53 and 65 wk of age. 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.