Effect of Threonine Supplementation on Growth Performance, Metabolizable Energy, Morphological Changes and Immune Response in Broiler Chickens Challenged with Coccidia

Abstract

This study was performed to investigate the effects of dietary threonine (Thr). level on performance, metabolizable energy, intestinal morphology, and immune system in coccidian–infected broiler chickens. The diets contained: 88%, 100% (Non challenged (NC) and challenged control (PC)), 112%, 124%, and 136% of Thr requirement according to Cobb 500 recommendation and fed during grower (pre challenged) and finisher (post challenged) periods. On d 23 (end of grower period), each bird received 0.5 mL of distilled water or received around 24000 sporulated oocysts. On d 23 and 31, one bird per replicate was slaughtered to measure the performance criteria. Mean dietary apparent metabolizable energy corrected for nitrogen (AMEn) and digestible energy were greater in NC birds than the challenged birds fed on 88% or 100% Thr diets. Feed intake and blood parameters were not significantly influenced by increasing levels of Thr in the diet. Compared with unchallenged birds with coccidia (NC), the growth performance, morphological parameters (not crypt depth), and immune responses decreased (P response and normal growth maintenance of the birds contaminated with coccidia.

Keywords

• coccidia
• threonine
• broiler chicken
• intestinal morphology