Burdur Mehmet Akif Ersoy University, Faculty of Veterinary Medicine, Department of Physiology, Burdur, Turkey
*Ahu Demirtaş: firstname.lastname@example.org
Capsaicin that is a major pungent component of red pepper is widely used as food additive and considered to be an antimicrobial factor. In this study, it was aimed to determine the effects of capsaicin on the growth of pure cultures of Gram-positive and Gram-negative rumen bacteria to evaluate potential of capsaicin as an alternative to ionophore antibiotics in modification of ruminal fermentation. The antibacterial activity assays of capsaicin were carried out using broth microdilution method under strictly anaerobic conditions inside an anaerobic chamber. Capsaicin was used in a dose range of 0.5-256 µg/mL. Capsaicin exhibited potential antibacterial activity on Ruminococcus flavefaciens and Methanobacterium formicicum (p<0.05), although it did not inhibit these bacteria completely. On the other hand, capsaicin showed growth stimulatory effect on Ruminococcus albus at 0.5-128 µg/mL doses (p<0.05), while potential antibacterial activity was observed at 256 µg/mL (p<0.05). Growth of other Gram-positive rumen bacteria, Butyrivibrio fibrisolvens and Eubacterium ruminantium were stimulated by capsaicin at 0.5-64 µg/mL and 8-128 µg/ mL doses, respectively (p<0.05), however stimulatory effects disappeared at higher concentrations. Capsaicin had stimulatory effects on Streptococcus bovis from Gram-positive bacteria at all used doses (p<0.05). Capsaicin also showed stimulatory effects on the growth of Gram-negative rumen bacteria, Megasphaera elsdenii and Fibrobacter succinogenes, at 0.5-128 µg/mL and 1-256 µg/mL concentrations, respectively (p<0.05). Stimulatory effects of capsaicin on some hydrogen, formate and lactate producer Gram-positive rumen bacteria suggested that the mechanism of action of capsaicin in the rumen may be different from ionophore antibiotics.
Keywords: Antibacterial, capsaicin, rumen bacteria