Effect of Milk Thistle (Silybum marianum) Seed on Performance, Nutrient Digestibility and Small Intestine Morphology of Broiler Chickens

The present study investigated the effect of different levels of milk thistle (Silybum marianum) seed on performance, nutrient digestibility and small intestine morphology of broiler chickens. For this purpose, 256 broiler chicks (Ross 308) were randomly assigned to four treatments with four replications and 16 chicks in each replication, by employing a completely randomized design. Treatments were included: 1) control, 2) basal diet + 0.2 % milk thistle seed, 3) basal diet + 0.4 % milk thistle seed and 4) basal diet + 0.6 % milk thistle seed. The results showed that the use of different levels of milk thistle increased feed intake compared with the control, but weight gain decreased with increasing levels of milk thistle (P 0.05). The feed conversion ratio increased by adding milk thistle to the diet (P 0.05). The addition of different levels of milk thistle in the diet reduced the digestibility of dry matter and organic matter compared with the control but did not have a significant effect on the digestibility of ether extract and ash. The concentration of serum LDL-c, VLDL-c and triglyceride was decreased by 0.6% milk thistle (P 0.05). The jejunal villus height and villus height to crypt depth significantly decreased using 0.2% milk thistle seed in the diet of broilers (P 0.05). The villus height to crypt depth in the ileum increased by milk thistle seed (P 0.05). In general, the milk thistle had no positive effect on growth performance, digestibility of dry matter and organic matter, and intestinal morphology. Therefore, according to the results of this study, it is not recommended to use milk thistle seed in broiler chickens diet.