Many natural growth promoters such as prebiotics, probiotics and medicinal plant extracts, have been investigated in poultry for their potential to improve health and production animal. Plant additives are considered to be technically, biologically and economically viable alternatives to feed antibiotics as they present fewer safety concerns related to inclusion levels and residuals in the end product. Research has shown that medicinal powders supplemented in swine and poultry diets are effective in increasing BW, intestinal health, nutrient digestibility, antioxidative potential and immunity with decreasing the incidences of diarrhea.

Anacardium occidentale L. (A. occidentale), which originated in Brazil but is now spread around the world, is reported to have many medicinal properties, including hypoglycemic and antihypertensive effects in rats, molluscicide against snails (Biomphalaria glabrata), bactericidal, anthelmintic and antiinflammatory activities. Specifically, powdered leaves of A. occidentale have an acceptable content of minerals (mainly electrolytes), saponifiable materials, monounsaturated fatty acids, phytosterols, soluble proteins and tannins, and has been shown to an effective therapy for incidences of diarrhea in poultry, pigs, guinea pigs, sheep, rabbits, cattle and humans.

Recently, a study conducted by the doctors Yordan Martínez Aguilar from Study Center of Animal Production, University of Granma, Cuba and Gang Liu from Institute of Subtropical Agriculture, Chinese Academy of Sciences（ISA) and other collaborators have confirmed the biological effective of the medicine plants, specifically the A. occidentale powder as new natural growth promoter on diets pullet.

Usually the medicinal effects of plants are for its content in secondary metabolites; however, its effect depends of the concentration of these compounds and its supplementation in the diets. The results shown that low concentrations of this powder (0.5 %) improved the body weight up to 56 days of old. However, higher levels of supplementation (1.0 and 1.5 %) provoked the decreased of BW. Moreover, the supplementation of this medicinal powder increased the immune organs relative weight, as well as, the relative weight of the digestive organs and accessories showed variations to 35 and 56 days of old.

According to Dr. Martínez and Dr. Liu, the supplementation of A. occidentale powder can reduce the pathogenic bacteria and modulate a better immune response in pullet, for the biological activity of the secondary metabolites, specially the tannins, coumarins and reducing sugars contents in the leaves of this plant.

In summary, this study is an example to demonstrate the importance the use of medicinal plants on diet animals, specially the Anacardium occcidentale powder on diets pullet, considering that this category poultry has a high proliferation of pathogenic bacteria by vertical transmission (progenitors). This is the first report of the utilization of this medicinal plant with this purpose, also recommended the use of low concentrations of this medicinal product.

The main findings of this research have been published on Journal of Food, Agriculture and Environment Vol.11 (3&4) (http://world-food.net/products/scientific-journal-jfae/).