Effect of an immunomodulatory feed additive on markers of immunity in pasture‐fed dairy cows

Abstract

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.

Yeast-containing feed additive alters gene expression profiles associated with innate immunity in whole blood of a rodent model

“…We previously reported that one of the most widely used immunomodulatory feed supplements, YCA, decreased mammary infections in dairy cows and improved milk production, 4 and improved innate and adaptive immune responses function in immune-challenged ruminant livestock. [1][2][3][4][5][6] This study closes an important gap in our knowledge, as it helps to explain the improved innate and adaptive immune responses reported in ruminant livestock fed YCA. At the same time, we want to caution the reader, as gene expression may or may not translate into changes on the protein level and/or functional changes like our previously observed TCA-induced changes in L-selectin gene and protein expression across various ruminant species.…”

“…We documented in several studies that feeding a yeast-containing additive (YCA; OmniGen-AF; Prince Agri Products, Inc., Quincy, IL, USA) at the recommended inclusion rate (0.25-0.50 wt% of diet) promotes immune function and maintains health and production in immune-or stress-challenged ruminant species and rodent models. [1][2][3][4][5][6] For example, Holstein heifers supplemented for 30 d with YCA had significantly increased surface-bound and internalized Escherichia coli in neutrophils. 5 Feeding YCA to the same animals tended to increase binding and uptake of Staphylococcus aureus by neutrophils.…”

“…1 Dairy cows supplemented for 5 wk with YCA had increased milk production, decreased incidence of mastitis and decreased somatic cell counts in milk, 4 and dairy cows supplemented for 60 d with YCA had increased gene expression of the neutrophil-activating chemokine receptor IL-8 R and the lymphocyte adhesion molecule L-selectin in whole blood. 6 After we had observed that feeding YCA increased responses to several bacterial pathogens across various species, we believed that the effect of feeding YCA on the immune system is more general than can be explained solely by the response of L-selectin and IL-8 R to YCA. Therefore, we hypothesized that YCA at 0.5% of diet increased expression of genes involved in several pathways involved in innate and cell-mediated adaptive immune responses in whole blood during a 28-d supplementation period and that higher inclusion rates (1% of diet) than currently recommended are not required in healthy, unchallenged animals.…”

In this issue – December 2014

“…A placebo‐controlled study conducted in a small pasture‐based commercial dairy herd investigated the effects of a feed supplement containing hydrated aluminium silicate, silicon dioxide and yeast extract on the expression of the immune markers that are active against bacterial infections 3. Supplements were mixed with liquid molasses and water and then added to the grain.…”

“…A placebo-controlled study conducted in a small pasture-based commercial dairy herd investigated the effects of a feed supplement containing hydrated aluminium silicate, silicon dioxide and yeast extract on the expression of the immune markers that are active against bacterial infections. 3 Supplements were mixed with liquid molasses and water and then added to the grain. Concentrations of mRNA for L-selectin and interleukin-8R were significantly higher in the treatment group than in controls at day 60, the final day of supplementation; however, they decreased slightly after that.…”