ABSTRACT
BACKGROUND: Infectious diseases in dairy cows often follow a time of nutritional or physiological stress and the subsequent altered immune system function. This study aimed to determine if the immunomodulatory effects of a feed additive previously observed in experimental animals and housed cattle fed total mixed rations could be reproduced in pasture-fed dairy cattle under Australian conditions. METHODS: The study included 34 pasture-fed dairy cattle given the treatment (n = 17) or placebo (bentonite, n = 17) for an acclimation period of 15 days followed by 60 days of supplementation. Blood tests were taken pre-trial and then 30, 60 and 90 days after acclimation. Blood samples were extracted and preserved in Trizol and analysed for immune markers. RESULTS: Pasture-fed dairy cows in the treatment group had significantly higher levels of the immune markers interleukin-8R and L-selectin in comparison with placebo-fed cows at 60 days after the start of supplementation. CONCLUSION: The immunomodulatory effects of the additive observed in the current study and the associated enhanced neutrophil function demonstrated by other studies suggest a role in decreasing the rates of mastitis and other infectious diseases of dairy cattle, particularly during times of nutritional or physiological stress.
Subject(s)
Cattle Diseases/prevention & control , Cattle/immunology , Dairying/methods , Interleukin-8/blood , L-Selectin/blood , Aluminum Silicates/administration & dosage , Animal Feed , Animal Nutritional Physiological Phenomena , Animals , Bentonite/administration & dosage , Cattle/blood , Dietary Supplements , Immunomodulation , RNA , Real-Time Polymerase Chain Reaction , Silicon Dioxide/administration & dosageABSTRACT
The plant alkaloid tetrandrine was shown to have significant inhibitory effects on receptor-ligand-mediated histamine release from rat mast cells at concentrations similar to or lower than that observed with theophylline and sodium cromoglycate. Inhibition of histamine release did not occur when non-specific stimulants such as aspirin, A23187 or adenosine triphosphate were used. Inhibition of ovalbumin-IgE and concanavalin A-mediated histamine release was reversible by washing the cells, showing that tetrandrine does not bind tightly to the cell membrane or cytoplasmic components. These results, taken together with previous reports of its anti-phagocytic, anti-oxidant and immunosuppressive properties, suggest that tetrandrine may be a broad spectrum non-steroidal drug of potential value in the treatment of allergic diseases.
