Data/hora: 13/06/2024 04:31:00

Provedor de dados: 	96	
País: 	Brazil	
Título: 	Calcium levels and calcium: available phosphorus ratios in diets for white egg layers from 42 to 58 weeks of age	
Autores: 	Pastore,Silvana Marques; Gomes,Paulo Cezar; Rostagno,Horacio Santiago; Albino,Luiz Fernando Teixeira; Calderano,Arele Arlindo; Vellasco,Cássia Rampini; Viana,Gabriel da Silva; Almeida,Rodrigo Lopes de.	
Data: 	2012-12-01	
Ano: 	2012	
Palavras-chave: 	Birds; Mineral; Performance; Requirement.	
Resumo: 	The experiment was conducted to determine the nutritional requirement of calcium and the best calcium:available phosphorus ratio for commercial layers at the post-laying peak. A total of 324 Hy-Line W-36 laying hens were utilized in the period from 42 to 58 weeks of age, distributed in a completely randomized design in a 3 × 3 factorial arrangement, composed of three levels of calcium (39, 42 and 45 g/kg) and three calcium:phosphorus ratios (12.12:1; 10.53:1; and 9.30:1), totaling nine treatments with six replications and six birds per experimental unit. There was no significant effect from the calcium levels × calcium:phosphorus ratio interaction for any of the variables studied. The calcium levels and the calcium:phosphorus ratios did not affect the variables performance or egg and bone quality. At the evaluation of the calcium:phosphorus balance, as the levels of calcium of the diet were raised, the intake of calcium and phosphorus and the contents of mineral matter and calcium in the excreta increased linearly, and the retention of calcium by birds decreased linearly. With the reduction of the calcium:phosphorus ratios of the diet, intake, retention and excretion of phosphorus by layers increased. Diets containing calcium at 39 g/kg and a calcium:phosphorus ratio of 12.12:1, corresponding to an increase in calcium of 3.51 g/bird/day and available phosphorus of 289 mg/bird/day, meet the requirements of calcium and available phosphorus of white egg layers in the period from 42 to 58 weeks of age.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982012001200007	
Editor: 	Sociedade Brasileira de Zootecnia	
Relação: 	10.1590/S1516-35982012001200007	
Formato: 	text/html	
Fonte: 	Revista Brasileira de Zootecnia  v.41 n.12 2012	
Fonte: 	info:eu-repo/semantics/openAccess