Effect of Dietary Threonine and Age after Hatching on Interleukin- 8 Gene Expression in Intestinal Tissue of Broiler Chicken

The aim of present research study was to study influence of different levels of threonine amino acid (equal to requirements of NRC (1994)، average of NRC (1994) requirements and ROSS (2007)، requirements ROSS (2007) and more than requirements of ROSS (2007)) and age after hatching on interleukin-8 (IL8) gene expression in intestinal tissue in broiler chickens. Threonine requirements in accordance with the recommendations ROSS (2007) are 14% higher than NRC (1994). In the first experiment، effect of threonine on IL8 gene expression in the jejunum in Ross male broilers and also in the second experiment، effect of age on IL8 gene expression was studied after hatching. In the first experiment، different levels of threonine were: 1) 0. 8%، 2) 0. 87، 3) 0. 94 % and 4) 1. 01%. At 14 d، one bird from each replicate was killed and the jejunum tissue samples were obtained. In the second experiment، from first experiment 1 treatment that level of threonine amino acid diet was 0. 8%، at 1، 3، 6 and 9 d، a bird killed and jejunum tissue samples were obtained in accordance with first experiment. Trizol kit was used for RNA extraction. Then remove genomic remnants and cDNA was synthesized. Realtime PCR reactions using primers and SYBR Green kit was performed. Experiments results showed that IL8 mRNA expression in jejunum tissue increased during the first 14 days of live chickens with increase threonine amino acid level until 0. 94 percentage diet (P<0. 0001) and also with age increase (P<0. 01).