Effect of propolis on Nosema ceranae infection under laboratory conditions.

PORRINI M. P.; DAMIANI NATALIA; MENDOZA YAMANDÚ; PAULA M. GARRIDO; NEGRI PEDRO; INVERNIZZI CIRO; EGUARAS MARTÍN J

KIEV

Congreso; 43º International Apicultural congress Apimondia; 2013

Apimondia

Propolis have shown an interestingpharmacological activity against several bee diseases but its activity against Nosema ceranae have not been previously evaluated.The effects of propolis administration pre and post infection with N. ceranae spores were studied in two bioassays(A and B, respectively). Combs obtained from healthy colonies were incubateduntil imagoes emergence. In assay ?A?, three propolis soft extracts fromdifferent geographical locations of Pampean region from Argentina were administered ad libitumin candy (5% w/v) during 10 days. Three replicates of 20 bees were employed foreach extract and control treatments. Eleven days post emergence, mass inoculationwas performed with 3ml of sugar solution containing 6,3x106 spores/mlor control solution. Ten bees per replicate were removed 10 days post infection(p.i.), and its midguts dissected to measure intensity of spores. In assay ?B?,one of the propolis extract selected from trial ?A?, was administered in candy(5% w/v) after individual inoculation with 7.0x104 spores. Individualswere removed at 7 and 14 days p.i. Feed intake and mortality of bees were dailymeasured during both assays. Spores intensity values showed no differencesbetween propolis and control treatments (Assay A: Kruskal-Wallis test, P<0.05; Assay B: T- test, P=0.6 on day 7 p.i. and P=0.099 on day 14 p.i.). Thepropolis treatments were consumed avidly, with daily average of 0.05g/bee. Survivalcurves showed no differences between treatments in both assays (Gehan-Breslow test,Assay A: P= 0.63; Assay B: P= 0.54). Results have demonstrated the absence ofantiparasitic activity of propolis against N.ceranae (including protective or post infection administration). Also, thelevel of activity did not depend on location origin of the propolis. However,the avidity of consume and the absence of lethal effects makes feasible the useof propolis in long term systemic administration assays.