Níveis de fitase e redução de cálcio em dietas de frangos
Nenhuma Miniatura disponível
Data
2019-12-06
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
Two experiments were conducted at the Poultry Department of the Federal University of Goias to
evaluate the inclusion of different phytase doses and reduction of calcium levels in diets of broiler
chickens from 1 to 42 days old. In the first experiment the experimental design was completely
randomized with six treatments, eight replications and 18 birds in each plot. In the second
experiment the experimental design was completely randomized with six treatments, six
replications and 10 birds in each plot. The treatments consisted of three levels of Ca (100%, 82%
and 64%) and two phytase inclusions 750FTU / kg and 1500FTU / kg of feed. The 1.011% level
was considered as 100% of the calcium recommendations for the pre-initial phase, 0.907% for the
initial, 0.822% for growth and 0.661 for the final phase. For the phosphorus (P) requirement in the
diet, the requirement of each phase was reduced by 0.150% for the treatments. Phytase overdose
improved feed intake weight gain (P <0.05). In the first experiment, at 21 days of age, 36%
calcium reduction and phytase supplementation of 1500FTU provided higher final weight, weight
gain and feed intake (P <0.05). At 42 days, 1500FTU phytase supplementation improved final
weight, weight gain and feed conversion. Reducing calcium inclusion improved feed conversion (P
<0.05). Phytase supplementation of 1500FTU and calcium reduction by 18% showed higher
carcass yield (P <0.05). In the first experiment, phytase overdose (1500FTU / kg of feed) increased
the length, diameter, weight and bone strength of 21-day-old chicken (P <0.05). Regarding bone
quality of broilers at 42 days of age, there was only effect of phytase factor for bone length and
diameter (P <0.05). When birds were supplemented with 1500FTU phytase / kg feed, there was no
effect of calcium levels on bone breaking strength (P <0.05). In the first experiment, reducing
calcium inclusion in diets reduced cooking fluid loss and increased shear force of chicken breast
meat (P <0.05). The inclusion of 1500FTU of phytase provided less liquid loss by thawing (P
<0.05). The reduction in calcium inclusion associated with phytase supplementation decreased
shear strength (P <0.05). In the second experiment, there was no effect of calcium levels and
phytase enzyme supplementation on the incidence of woody breast at 42 days of age (P> 0.05).
Regarding the histopathological evaluations, in the second experiment, the treatments were not
effective in the action on meat quality (P> 0.05). Up to 36% reduction in calcium supplementation
with inclusion of 1500 FTU / kg phytase can be used without adverse effects on performance, bone
quality and meat quality of 42-day-old broilers.
Descrição
Palavras-chave
Citação
COSTA, M. A. Níveis de fitase e redução de cálcio em dietas de frangos. 2019. 88 f. Tese (Doutorado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2019.