The Expression of Selected Cytokine Genes in the Livers of Young Castrated Bucks after Supplementation with a Mixture of Dry Curcuma longa and Rosmarinus officinalis Extracts

SIMPLE SUMMARY: Turmeric (Curcuma longa) and rosemary (Rosmarinus officinalis) are broadly used in many cuisines as spices/herbs and, containing active components, they contribute to reducing inflammation. As goats can serve as the animal model of some human conditions, our findings can broaden our knowledge of human metabolism and the impact of supplements on human health. The study aims to determine the effect of supplementation with a mixture of dried turmeric and rosemary extracts on the cytokine gene expressions in the livers of twenty eight-month-old castrated goat bucks. Their mean live weight at the beginning of experiment was approx. 30 kg. In the treated group a dose of 1.6 g/day/buck was administered orally for 124 days. After slaughter, liver fragments were collected. Total RNA was then isolated and RT-qPCR was performed. Treatment resulted in reduced IL-12 expression and higher IL-18 expression which may indicate a hypersensitivity reaction caused by an excessive supplement dose. Increase in the IFN-γ expression was also noted which may indicate that the supplement has pro-inflammatory effect. The observation that a small dose of mixture can induce an allergic reaction in young bucks suggests that high levels of curcumin and/or turmeric extract may exert some impact on the immunological system function of humans. ABSTRACT: The study aims to determine the effect of supplementation with a mixture of Curcuma longa and Rosmarinus officinalis extracts (896:19 ratio) on the expression of 15 cytokine genes in the livers of 20 castrated goat bucks. Two equal groups were created: treated and control groups. The treated group was provided a mixture (1.6 g/day/buck) for 124 days. Liver tissue samples were collected after slaughter. The gene expression was analyzed using RT-qPCR with two reference genes. Variance analysis was conducted using a model with the group fixed effect. IL-2 and IL-8 expression was below the detection level. No differences were found for IL-1α, IL-1β, IL-4, IL-6, IL-10, IL-16, IFN-α, IFN-β, TNF-α, and CCL4 expressions, suggesting that supplementation does not activate cytokine production in the healthy hepatocytes. The treated group demonstrated lower IL-12 expression (p < 0.05) and a tendency for higher IL-18 and INF-γ (0.05 < p < 0.10) expressions, which may indicate a hypersensitivity resulting from excessive supplement dose. The increased IFN-γ expression could be caused by the increased IL-18 expression. If a small dose of extract can induce an allergic reaction in young goat bucks, it is also possible that humans may be susceptible to an overdose of curcumin and/or turmeric extracts.