*Article* **Screening of Dietary Ingredients against the Honey Bee Parasite** *Nosema ceranae*

**Chiara Braglia 1, Daniele Alberoni 1,\*, Martin Pablo Porrini 2,3, Paula Melisa Garrido 2,3, Loredana Baffoni <sup>1</sup> and Diana Di Gioia <sup>1</sup>**


**Abstract:** *Nosema ceranae* is a major pathogen in the beekeeping sector, responsible for nosemosis. This disease is hard to manage since its symptomatology is masked until a strong collapse of the colony population occurs. Conversely, no medicaments are available in the market to counteract nosemosis, and only a few feed additives, with claimed antifungal action, are available. New solutions are strongly required, especially based on natural methods alternative to veterinary drugs that might develop resistance or strongly pollute honey bees and the environment. This study aims at investigating the nosemosis antiparasitic potential of some plant extracts, microbial fermentation products, organic acids, food chain waste products, bacteriocins, and fungi. Honey bees were singularly infected with 5 <sup>×</sup> <sup>10</sup><sup>4</sup> freshly prepared *N. ceranae* spores, reared in cages and fed ad libitum with sugar syrup solution containing the active ingredient. *N. ceranae* in the gut of honey bees was estimated using qPCR. The results showed that some of the ingredients administered, such as acetic acid at high concentration, p-coumaric acid, and *Saccharomyces* sp. strain KIA1, were effective in the control of nosemosis. On the other hand, wine acetic acid strongly increased the *N. ceranae* amount. This study investigates the possibility of using compounds such as organic acids or biological agents including those at the base of the circular economy, i.e., wine waste production, in order to improve honeybee health.

**Keywords:** nosemosis; *Vairimorpha ceranae*; nisin; *Saccharomyces* sp.; acetic acid; para-coumaric acid; gut microbiota
