Data/hora: 11/06/2024 12:20:39

Provedor de dados: 	89	
País: 	Brazil	
Título: 	Effects of different levels of dietary crude protein and threonine on performance, humoral immune responses and intestinal morphology of broiler chicks	
Autores: 	Abbasi,MA; Mahdavi,AH; Samie,AH; Jahanian,R.	
Data: 	2014-03-01	
Ano: 	2014	
Palavras-chave: 	Body weight gain; Broilers; Immunocompetence; Jejunal histological morphology; Protein and threonine.	
Resumo: 	The present study aimed at investigating the effects of different dietary crude protein (CP) and threonine (Thr) levels on the performance, immune responses and jejunal morphology of broiler chicks. A total of 432 broiler chicks were randomly assigned to a 3×3 factorial arrangement of treatments including three different CP dietary levels (90, 95, and 100% of Ross 308 recommendations) and Thr (100, 110, and 120% of Ross specifications) dietary levels. Performance parameters were recorded for the starter (1-12 days), grower (13-24 days) and finisher (25-42 days) periods. Birds were subjected to different antigen inoculations to evaluate antibody responses. At day 42 of age, two randomly-selected birds per replicate were slaughtered to measure carcass traits. Although Thr dietary supplementation had no marked effect on Newcastle antibody titers, particularly the supplementation of Thr up to 110% of Ross specifications improved (p&lt;0.05) antibody titers against sheep red blood cells during both primary and secondary responses. Reduction of dietary CP level resulted in significant decrease in villus height (p&lt;0.05) and crypt depth (p&lt;0.01) in jejunal epithelial cells, but the supplementation of low-CP diets with Thr up to 110 and 120% of the recommended values allowed overcoming these changes. Except for the starter period, reducing dietary CP level to 90% of Ross recommendations had no harmful effects on performance parameters; however, the best values were obtained with diets containing 110% Thr. The present results indicate that it is possible to reduce dietary CP level up to 10% after the starter period without any detrimental impact on growth performance, and dietary Thr supplementation up to 110% of Ross values may compensate for low CP-induced growth delay in broiler chicks.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2014000100005	
Editor: 	Fundação APINCO de Ciência e Tecnologia Avícolas	
Relação: 	10.1590/S1516-635X2014000100005	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Poultry Science  v.16 n.1 2014	
Fonte: 	info:eu-repo/semantics/openAccess