Essential Oils to Improve Animals’ Immunity?

Few substances can be found in nature as polyvalent as essential oils. Many studies have demonstrated their effects on performance parameters and gut health, improving villus height and modulating the intestine’s microbiota amongst other actions. But could it have any effect on the immunity of the animals?

On 2004 Walter et al designed a test where 49 growth-retarded growing-finishing pigs of the same age were assigned to two groups, a control with a regular finishing diet and an experimental group with the same diet and oregano oil. They observed that the proportion of lymphocytes in peripheral blood was significantly higher in the pigs supplemented with oregano than in the control animals.

Later on, on 2011, Ariza-Nieto evaluated the effects of supplementing sow diets with oregano essential oil (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. They could not observe significant results on growth potential and immune responses in suckling piglets. However, milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01).

Another example is the trial that Yan and Kim carried out on 2012. A total of 96 pigs (BW=26.56±0.42 kg) were assigned to 1 of 3 treatments: control (basal diet; CON); basal diet + eugenol; basal diet + cinnamaldehyde. Dietary CT and ET led to a higher (p<0.05) lymphocyte concentration compared with CON. The inclusion of CT and ET decreased (p<0.05) the fecal E. coli concentration.

In conclusion, although these trials could not show clear evidence as to whether essential oils can significantly improve the animals’ immunity, they seem to suggest that essential oils have the power to modify some of its aspects. Therefore, there should be further investigation to learn what are these mechanisms that affect the animals’ immunity and how to use the essential oils to obtain the maximum benefit for producers