Alternative sources of fat and zinc in broiler breeder diets and their influences on performance
Hudson, Benton Patrick
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Experiments were conducted to evaluate the influences of dietary fat and zinc sources on broiler breeder or progeny performance. The first experiment indicated that providing Menhaden oil rather than poultry fat in broiler breeder male diets maintained higher fertility of eggs laid during the second week following single inseminations at different ages. However, sperm quality measurements did not reveal differences between semen from the two male groups. A series of experiments were conducted to determine the effects of zinc source on performance and immune status of broiler breeder hens and their progeny. From 0 through 65 weeks of age, broiler breeder hens were given diets supplemented with 160 ppm zinc from ZnSO4, Availa®Zn zinc-amino acid complex, or a mixture of ZnSO4 and Availa®Zn. Eggshell quality was enhanced when a mixture of the two zinc sources was provided. As a result, fewer cracked eggs were produced and hatching egg production and estimated chick production were increased. There was a direct relationship between Availa®Zn intake and humoral and cellular immune responses. Two different experiments were conducted with progeny from these hens. On both occasions, chicks were provided 140 ppm supplemental zinc as ZnSO4 or a mixture of ZnSO4 (100 ppm) and Availa®Zn (40 ppm). In experiment 1, the chicks were subjected to either low or normal brooding temperatures. Humoral immune status of broilers was increased when hens were provided diets with ZnSO4, but dietary zinc source did not influence broiler performance. Mortality, feed intake and body weight were increased when broilers were subjected to cold temperatures. In experiment 2, body weight gain and feed conversion were enhanced when broilers were provided a mixture of ZnSO4 and Availa®Zn. These data suggest that ZnSO4 and Availa®Zn may have synergistic effects, improving bird performance. Finally, influences of hen age and zinc source in hen diets on physiological development of chicks were evaluated. Results indicated that yolk sacs and hearts were less developed in progeny from young hens and may limit broiler performance.