Novel environment: modulation of innate immune responses of bulls

Introduction: The common molecular basis of the responses to infectious and non-infectious stressors is mainly represented by the accumulation of products related to tissue damage (DAMPs), such as salts, ATP, ROMs, uric acid, mitochondrial DNA. This can be also induced by the metabolic and psychotic stressors, underlying innate immune responses to a novel environment. Material and Methods: 26 Friesian young bulls were investigated after truck transportation from 10 different dairy farms to a breeding center. Bulls were clinically inspected, and selected parameters of innate immunity (serum bactericidal activity, hemolytic complement, serum albumin, α, β, and γ-globulins, interleukin-6, TNF-α) were investigated at days -4/0/4/15/30 with respect to shipment in different seasons. Results: Significant differences of IL-6 and TNF-α mean protein levels were shown at destination in December (94 pg/ml) and June (788 pg/ml), respectively. Moreover, the serum levels of these cytokines increased between days 0 and 15 after the arrival, the modulation of IL-6 being in agreement with established models of physical and/or psychological stress. Concerning the modulation of albumin, alpha and beta-globulins, the highest levels were detected in April, whereas a significant decrease was observed between day 15 and 30 after arrival; on the contrary, γ-globulin levels significantly increased after day 15. Conclusion: The results of this study highlight the occurrence of innate immune responses of young bulls to the combined effects of climate (season) and novel farming conditions.