June 22, 2020

Vilofoss' X-Zelit improves dairy cow's immune systems

Vilofoss' X-Zelit feed for dairy cows improves the immune function as observed in a decreased expression of neutrophil inflammatory mediators, the company said recently, referring to a new study.

In the New Zealand-based study, X-Zelit was used to demonstrate the expression of neutrofile genes in hypocalcemic and normocalcemic dairy cows. An effect of the X-Zelit on the immune function was expected as X-Zelit increases the calcium level in periparturient cows.

Calcium is an important messenger during immune cell activation and depends on intracellular stores. Hypocalcemia has also been shown to have a detrimental effect on neutrophil respiratory burst.

The study was performed on cows grazing fresh pasture that was supplemented with 500g of X-Zelit/cow mixed into the maize silage for at least 2 weeks pre-partum. Control cows were offered same diet but without X-Zelit supplemented in the feed ration.

Plasma calcium levels were significantly improved during day 0, 1 and 4 after calving compared to the control level, demonstrating the calcium stabilising effect of X-Zelit product.

A total of 21 genes were tested in this trial, with two of them significantly lower for the X-Zelit group and the rest of the six lower than the control group. The few genes affected suggest that X-Zelit did not affect several pathways involved in neutrophil functions.

The gene expression of calcium depends on immune mediators S100A8, S100A11 and S100A13; it was lower for the X-Zelit supplemented cows. The up-regulation of these genes has been associated with severe negative energy balance and expression is associated with intrauterine infections. The up-regulation of these genes indicates the presence of bacteria and consequent inflammation in certain circumstances.

Expression of CXCR1 was lower for the X-Zelit group. In cattle, CXCR1 has been associated with impaired neutrophil expression and increased susceptibility to mastitis.

CXCR4 is a key regulator of neutrophil releasee from bone marrow under standard and stress conditions. It has also been associated with neutrophil ageing. The lower expression of CXCR4 in the X-Zelit-treated animals indicates that the neutrophils are younger and these animals may have less periparturient inflammation compared with control animals. The further indication of a reduced inflammation is down-regulation of the genes that encodes pre-inflammatory cytokine interferon gamma (IFNG).

It was concluded that X-Zelit down-regulates the immune regulators over the transition period, thus suggesting a dampening of inflammation in X-Zelit-treated cows, which may be indirect results of alterations to mineral availability.

- Vilofoss