Effect of milk thistle (Silybum marianum L.) oil on pro-inflammatory cytokines, acute phase proteins, rumen metagenomic profile, rumen fluid variables and performance in calves

The aim of this study was to determine the effect of milk thistle ( Silybum marianum L., SM) oil supplementation on proinflammatory cytokines, acute phase proteins, rumen metagenomic profile, rumen fluid variables and performance during the milk feeding period of Holstein calves. In the present study, 24 calves that consumed quality and sufficient amount of colostrum (≥50 mg/ml IgG) after birth were divided into three groups, with 8 animals in each group (4 males + 4 females). Individually fed calves were given added SM oil as 0 µL/day/calf (Control group, SM0), 100 µL/day/calf (SM100) and 200 µL/day/calf (SM200). The ration containing concentrated feed mix (90%) + wheat straw (10%) was offered to the calves. SM oil did not change the ammonia nitrogen and pH values of the rumen fluid of calf ( P >0.05). The molarities of PA, IBA, IVA and BSCFA in the rumen fluid increased linearly with SM oil dose ( P