The aim of this study was to evaluate the effects of in-ovo vaccination on different incubation days of broiler embryos derived from young and old breeders on incubation indexes, vaccine response, and broiler performance. A number of 20,160 fertile eggs was distributed according to a completely randomized design in a 4 x 2 factorial arrangement (inovo vaccination on 16, 17, 18, or 19 days of incubation, and breeders of 31 or 52 weeks of age), totaling eight treatments with 15 replicates of 168 eggs each. Vaccination procedures and vaccines (strains and doses) were those routinely applied in commercial hatcheries. After hatch, 960 male chicks were housed and distributed according to the same experimental design previously applied in the hatchery. There were hatching losses (p<0.05) when eggs were vaccinated before 18 days of incubation. Greater Marek's disease antibody titers were obtained when the in-ovo vaccination was performed on day 19 of incubation, regardless breeder age. Embryonic age at vaccination did not compromise broiler performance in the field, and the flexibility of embryonic age for in-ovo vaccination can reduces incubation costs.
The purpose of this trial was to supplement commercial broiler diets with optimum vitamin programs and higher availability of mineral sources, and to evaluate the effect on performance, yield and meat quality of broilers. The study used 1800 male broiler chicks randomly distributed in a 2 x 2 factorial design (vitamin programs -optimum and commercial vs. mineral sources -inorganic (sulfates) and carbo-aminophospho-chelate (CAPC)). Supplementation associating optimum vitamin levels and mineral source CAPC resulted in better feed conversion and higher carcass weight at 42 days of age (p<0.05). Supplementation of diets with optimum vitamin levels resulted in higher absolute and relative breast weight, lower abdominal fat deposition, and reduction (p<0.05) of broiler breast water loss by dripping. Supplementation with CAPC minerals resulted in higher breast weight, lower abdominal fat deposition, less elastic muscle tissue, that is, a higher level of tenderness resulting in less resistance of muscle fibers and skin with higher tear strength than the skin of birds fed inorganic sources. Associating optimum vitamin programs and CAPC mineral source resulted in lower (p<0.05) lipid peroxidation levels in thighs and drumsticks after 10 and 40 days freezing. No difference (p>0.05) was found in the association of vitamin programs and mineral sources on the occurrence of white striping and dorsal myopathy. Supplementing the diets with optimized vitamin programs associated with a more bioavailable mineral source resulted in a positive contribution to the meat quality of broilers.
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