Impact of Heat Stress, such as high temperature and humidity, on the immune system is reported in animals. The pivotal role of cytokines in modulating the immune response is well established. The aim of this study was to evaluate the serum levels of 4 major cytokines (IL-4, IFN-, TNF-, IL-6) in 21 Holstein stabled calves (age, 2-16 months) prior to and 4 days after exposure to a heat stress condition. Furthermore, clinicopathological variables potentially influenced by the latter condition, such as white blood cells count (WBC), plasma muscular enzymes (AST, LDH, CK), serum glucose and β-hydroxybutyrate, were evaluated as well. A condition of heat stress was defined by a mean daily value of Temperature-Humidity Index (THI) higher than 74 for 3 consecutive days. Serum cytokines concentrations were determined using a multiplex sandwich enzyme-linked immunosorbent assay (ELISA) based on chemioluminescent detection of the analytes (SearchLight Multiplex Immunoassay Kits, Aushon Biosystem). Following one week of normal climatic parameters (mean daily THI  68), a Heat Stress condition (mean daily THI = 76) was detected for 4 days in our population. In response to Heat Wave, serum concentrations of IL-4 significantly increased (P<0,01), whilst IFN- decreased (P<0,05). On the other hand, a significant change of serum concentrations of pro-inflammatory cytokines such as TNF- and IL-6 was not found. These modifications in cytokines profiles were accompanied by a significant increase of WBC and a significant decrease of plasma muscular enzymes (P<0.01 and P<0,05, respectively). Significant changes in serum glucose and β-hydroxybutyrate concentrations was not found. Our results suggest that a Heat Wave of at least 3-4 days of length is effective to impact on the immune system function of intensively farmed calves, shifting the immune response from a Th1-type (IFN- driven) to Th2-type (IL-4 driven). These immunological variations could reflect a depression of the cell-mediated immunity in spite of the increase of circulating leukocytes in the blood stream. WBC and plasma muscular enzymes modifications in our population are in agreement with data previously reported in the literature. Further studies to better define the role of cytokines in response to Heat Stress in a wider population of animals are warranted.
M. Giunti, F. Dondi, L. Scagliarini, M. Pietra, A. Scagliarini, A. Peli (2010). IMPACT OF HEAT STRESS ON IMMUNITY AND CLINICOPATHOLOGICAL VARIABLES IN CALVES: PRELIMINARY RESULTS.
IMPACT OF HEAT STRESS ON IMMUNITY AND CLINICOPATHOLOGICAL VARIABLES IN CALVES: PRELIMINARY RESULTS
GIUNTI, MASSIMO;DONDI, FRANCESCO;SCAGLIARINI, LORENZO;PIETRA, MARCO;SCAGLIARINI, ALESSANDRA;PELI, ANGELO
2010
Abstract
Impact of Heat Stress, such as high temperature and humidity, on the immune system is reported in animals. The pivotal role of cytokines in modulating the immune response is well established. The aim of this study was to evaluate the serum levels of 4 major cytokines (IL-4, IFN-, TNF-, IL-6) in 21 Holstein stabled calves (age, 2-16 months) prior to and 4 days after exposure to a heat stress condition. Furthermore, clinicopathological variables potentially influenced by the latter condition, such as white blood cells count (WBC), plasma muscular enzymes (AST, LDH, CK), serum glucose and β-hydroxybutyrate, were evaluated as well. A condition of heat stress was defined by a mean daily value of Temperature-Humidity Index (THI) higher than 74 for 3 consecutive days. Serum cytokines concentrations were determined using a multiplex sandwich enzyme-linked immunosorbent assay (ELISA) based on chemioluminescent detection of the analytes (SearchLight Multiplex Immunoassay Kits, Aushon Biosystem). Following one week of normal climatic parameters (mean daily THI 68), a Heat Stress condition (mean daily THI = 76) was detected for 4 days in our population. In response to Heat Wave, serum concentrations of IL-4 significantly increased (P<0,01), whilst IFN- decreased (P<0,05). On the other hand, a significant change of serum concentrations of pro-inflammatory cytokines such as TNF- and IL-6 was not found. These modifications in cytokines profiles were accompanied by a significant increase of WBC and a significant decrease of plasma muscular enzymes (P<0.01 and P<0,05, respectively). Significant changes in serum glucose and β-hydroxybutyrate concentrations was not found. Our results suggest that a Heat Wave of at least 3-4 days of length is effective to impact on the immune system function of intensively farmed calves, shifting the immune response from a Th1-type (IFN- driven) to Th2-type (IL-4 driven). These immunological variations could reflect a depression of the cell-mediated immunity in spite of the increase of circulating leukocytes in the blood stream. WBC and plasma muscular enzymes modifications in our population are in agreement with data previously reported in the literature. Further studies to better define the role of cytokines in response to Heat Stress in a wider population of animals are warranted.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
