Control of the microsporidian parasite Nosema ceranae in honey bees (Apis mellifera) using nutraceutical and immuno-stimulatory compounds

Abstract

Nosema ceranae is a microsporidian parasite that causes nosemosis in the honey bee (Apis mellifera). As alternatives to the antibiotic fumagillin, ten nutraceuticals (oregano oil, thymol, carvacrol, trans-cinnmaldehyde, tetrahydrocurcumin, sulforaphane, naringenin, embelin, allyl sulfide, hydroxytyrosol) and two immuno-stimulatory compounds (chitosan, poly I:C) were examined for controlling N. ceranae infections. Caged bees were inoculated with N. ceranae spores, and treatments were administered in sugar syrup. Only two compounds did not significantly reduce N. ceranae spore counts compared to the infected positive control, but the most effective were sulforaphane from cruciferous vegetables, carvacrol from oregano oil, and naringenin from citrus fruit. When tested at several concentrations, the highest sulforaphane concentration reduced spore counts by 100%, but also caused 100% bee mortality. For carvacrol, the maximum reduction in spore counts was 57% with an intermediate concentration and the maximum bee mortality was 23% with the highest concentration. For naringenin, the maximum reduction in spore counts was 64% with the highest concentration, and the maximum bee mortality was only 15% with an intermediate concentration. In the longevity experiment, naringenin-fed bees lived as long as Nosema-free control bees, both of which lived significantly longer than infected positive control bees. While its antimicrobial properties may be promising, reducing sulforaphane toxicity to bees is necessary before it can be considered as a candidate for controlling N. ceranae. Although further work on formulation is needed with naringenin, its effect on extending longevity in infected bees may give it an additional value as a potential additive for bee feed in honey bee colonies.

Effect of Immune Inducers on Nosema ceranae Multiplication and Their Impact on Honey Bee (Apis mellifera L.) Survivorship and Behaviors

“…Furthermore, Mayack et al [41] suggested that N. ceranae causes significant regulatory changes in the highly conserved octopamine hormone stress pathway, affecting the bee's life span and possibly their age polyethism. This study showed that both chitosan and peptidoglycan reduced N. ceranae spore counts by more than 60%, which confirms a previous report on chitosan's partial suppression of N. ceranae infections in honey bees [42]. However, although both PAMPs similarly reduced N. ceranae spore counts, chitosan was more effective in increasing survivorship of N. ceranae infected bees.…”

Extracts from Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. Roots: A New Hope Against Honeybee Death Caused by Nosemosis

“…0.124 µg of eleutheroside B, 0.055 µg of eleutheroside E and 0.001 µg of naringenin. Nevertheless, the main therapeutic and prophylaxis effect against Nosema infection is probably connected only with eleutherosides as in other studies, naringenin from citrus fruit had a moderate effect on reducing Nosema spore loads and its main advantage was the extension of honeybees’ lifetime [ 50 ].…”

Nosema ceranae in Apis mellifera: a 12 years postdetection perspective

“…Since the first report of N. ceranae infection in A. mellifera, there has been some controversy about the consequences of such infection. However, in recent years most studies have confirmed that N. ceranae has a pathogenic effect in this host, expressed at least in a shortening of the workers' lifespan in controlled (cage) experiment (e.g., Mayack and Naug, 2009;Alaux et al, 2010;Martín-Hern andez et al, 2011;Dussaubat et al, 2012;Goblirsch et al, 2013;Schwarz and Evans, 2013;Aufauvre et al, 2014;Basualdo et al, 2014;Roberts and Hughes, 2014;2015;Williams et al, 2014;Doublet et al, 2015aHuang et al, 2015; only few papers failing to report this effect (Milbrath et al, 2013;Retschnig et al, 2014;Garrido et al, 2016).…”

“…Similarly, a mixture of different species belonging to Lactobacillus , Bifidobacteria , Pediococci and Lactococci genera showed no advantageous effect on the infection (Endler, ). Another study including nutraceutical, prebiotic and probiotics showed acacia gum as the most effective prebiotic, although with a high mortality as side effect, and the probiotic Protexin Concentrate© single‐strain (ProtexinC1) as able to reduce the spores, increasing the bee survival (Borges, ).…”