Effects of Oak Acorn on Performance and Gene Expression of Hypothalamus Tissue in Broiler Chickens

Oak fruit is high in energy and, therefore, can be used as a substitute for corn in poultry diets. However, one limitation of oak fruit is its high level of antinutritional compounds (tannins). This study investigated the effects of corn replacement with oak acorns on performance traits and the mRNA levels of hypothalamic genes in broiler chickens. For this purpose, a total of 264 one-day-old broiler chickens were randomly assigned to three experimental treatments (0, 15, and 20 % oak acorn). Body weight gain, feed intake, and feed conversion were calculated on a pen basis at 21 and 42 days of age. The results showed that body weight gain and feed conversion were significantly affected by treatments at both 21 and 42 days of age; however, no significant difference was observed in feed intake among the treatments. At the age of 21 days, a significant difference in weight gain was observed among the three treatments, whereas this difference was not significant for the treatments with oak acorn on day 42. However, the lowest weight gain was observed in the 20% oak acorn diet at both ages. Feed conversion was significantly higher in 20% of the oak acorn treatment relative to the control group on day 42, while feed conversion was not affected by treatments at the age of 21 days. In addition, the mRNA levels of NPY, AgRP, and Ghrelin were significantly downregulated in the hypothalamus tissue of broilers fed diets containing oak acorn. At the age of 21 days, the expression levels of NPY showed a significant decrease in the hypothalamus tissue of broilers fed with 15% and 20% oak corn diets, while this decrease was significant for the AgRp and Ghrelin genes on day 42. In conclusion, these results suggest that replacing 15% and 20% of corn with oak acorn can negatively affect the performance and hypothalamic gene expression of broiler chickens.