Sayed, A.N.  <br/><br/>
Effect of dietary supplemental levels of vitamin a on the performance and immune response of heat-stressed broilers  [electronic resource]. 
 تأثير إضافة مستويت فيتامين أ على الأداء والاستجابة المناعية فى بدارى التسمين المجهدة حراريا. 

 - p.285-300 
<br/><br/>Includes references. 
<br/><br/> The experiment was conducted to evaluate the effect of vitamin A (Retinyl acetate, RA) supplementation of a broiler diet on the perfonnance and immune function of heat-stressed chicks. One hundred, one- day old of Arbor Acre chicks were randomly distributed into 4 equal groups (25 chicks/group). The first group was fed on the basal diet supplemented with 0.52 mg RAlkg diet to cover vitamin A recommendation ofNRC (1994), and considered as a control group. The NRC recommendation of vitamin A was folded ten times (5.2 mg RAlkg), twenty times (10.4 mg RAlkg) and thirty times (15.6 mg RAlkg) in the diets of the second, third and fourth groups, respectively. The growth perfonnance, feed intake and feed conversion were assessed. The second group fed on 5.2mg RA-supplemented diet achieved a body weight 1.18 times that of the control group at the end of the experiment, while the chicks of groups 3 & 4 supplemented with 10.4 and 15.6 mg RA scored lowest gain. 
<br/><br/><br/>Summary in Arabic. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Poultry--Feeding and feeds.<br/>Chickens--Physiology.<br/>Dietary supplements.<br/>Vitamin A in animal nutrition.<br/>Chickens--Immune response.<br/>Heat Stress Disorders.