Effects of diets with different levels of fennel (Foeniculum vulgare) seed powder on DLK1 gene expression in brain, adipose tissue, femur muscle and rumen of Kermani lambs.

• First investigation of the effect of fennel on DLK1 gene expression in Kermani lambs. • The fennel increases DLK1 gene expression in the femur muscle and in the rumen muscle. • Maximum gene expression rate was related to 2 % fennel in comparison to 0% in all studied tissues. • Fennel can be used for increasing DLK1 gene expression in some tissues. DLK1 (protein delta homolog 1) plays an important role in production of adipocytes, muscle development, wound healing, pancreas, liver and lung cells development and also in the development of meat quality, digestion and growth performance. Therefore, the goal of this research was to investigate the effects of different levels of fennel seed power in the diet on growth performance and on DLK1 gene expression in brain, adipose, femur (leg) muscle and rumen muscle tissues of Kermani lambs. Dietary treatments including different levels of fennel seed powder (0, 1 and 2 % of diet DM) were fed to 3 groups of lambs (each group contained 10 animals) for three months. Some physiological parameters relating to muscle and adipose development were measured. Tissues including brain, adipose tissue, femur (leg) muscle and rumen muscle were collected for expression analysis of the DLK1 gene. In this study, increasing the level of fennel seed powder in diets of lambs, increased the amount of DLK1 gene expression in the femur muscle and rumen tissues. Feeding 2 % fennel in comparison to the control diet (0 %) resulted in a significant difference in the amount of DLK1 gene expression in the femur (leg) muscle and in the rumen muscle (P < 0.05). Maximum gene expression rate was observed in all studied tissues of lambs fed diets with 2 % fennel in comparison to 0%. On the other hand, final weight, live daily gain, dry matter intake, warm carcass weight, weight of back muscle (loin), weight of femur (leg) muscle, weight of lean meat and eye muscle area were higher for animals fed with 2 % fennel than those fed control diet, but weight of liver was lower in animals fed with 2 % fennel than those fed control diet. In regards to the results of this investigation, it can be concluded that fennel can be used for increasing DLK1 gene expression in some tissues, like muscle, and consequently for increasing animal growth and muscle mass, which is important in the sheep industry. [ABSTRACT FROM AUTHOR]