Effect of different levels of oak acorn on pancreatic chymotrypsin gene expression in broilers chicken

In this study, the effect of dietary corn replacement with oak acorn on the expression of pancreatic chymotrypsin gene in broilers was investigated. The use of oak acorn in poultry feed can reduce feed intake, nutrient digestion and poultry performance by binding to dietary proteins and digestive enzymes. Therefore, the aim of this study was to evaluate the expression of pancreatic chymotrypsin gene in broilers fed with different levels of oak acorn. For this purpose, broilers were fed with three treatments (control, 15% and 20% oak flour) from 1 to 42 days of age. At 21 and 42 days of age, pancreatic tissue was isolated and weighed from 36 chickens (6 from each treatment at each age) after slaughter and then total RNA was extracted. To evaluate gene expression, chymotrypsin gene expression was compared with beta-actin gene as reference gene. To analysis of gene expression data, REST V2.0.13 software and SAS 9.1 software were used. At 21 days of age, no significant difference was observed in relative weight of pancreas between different treatments (p> 0.05), while at 42 days of age, relative weight of pancreas in 20% oak acorn treatment was significantly higher in compared to 15% oak acorn and control treatments (p <0.05). At 21 days of age, expression of chymotrypsin gene in broiler pancreas was not significantly different between treatments containing oak acorn compared to control, while on day 42, expression of chymotrypsin gene was significantly higher in treatments containing 15% and 20% oak acorn in relation to the control group (P <0.05). In general, increasing the level of oak acorn in the broilers diet due to the increase of phenolic compounds (tannins) and their binding to dietary proteins and digestive enzymes can reduce the digestion and absorption of proteins and amino acids and increased expression of protein digestive enzymes in the gastrointestinal tract.