The capability of the fungus Mucor circinelloides to maintain parasiticidal activity after the industrial feed pelleting enhances the possibilities of biological control of livestock parasites

Abstract

The ability of the spores of the ovicide fungus Mucor circinelloides to resist the industrial manufacturing of pelleted feed and retain their biological and parasitological activities has been tested. Firstly, survival of M. circinelloides spores at elevated temperatures was in vitro assayed. In a second assay, the spores of M. circinelloides were added in the mixing phase of the industrial pelleting of livestock (calves and horses) feed. The biological development (mycelium growth rates and sporogenesis) and the ovicidal activity on eggs of the parasites Fasciola hepatica and Parascaris equorum eggs were measured in plates. In the in vitro assay, a similar level of biological development in all the conditions except by heating the spores at 72 °C for 10 min were observed. Viability of F. hepatica eggs reduced to 55–60%, and 56–70% that of P. equorum eggs. After the addition of the spores to the meal previous to the pelletization phase, percentages of reduction of 54–58% viability F. hepatica eggs and 61–67% P. equorum eggs were recorded. It is concluded that the spores of M. circinelloides maintain their antagonistic effect against eggs of the parasites F. hepatica and P. equorum in industrially manufactured pellets, providing thus a very helpful tool to prevent infection by trematodes or ascarids among pasturing livestock.