Addition of prebiotic (acidifying) products to the supplementary feeds provided to honeybee colonies has a positive effect on colony health through favouring the development of a beneficial intestinal microflora. It also increases queen fecundity and oviposition leading to fast colony recruitment. We report the economic benefits of using acidifying substances (cider vinegar and lactic acid) in spring feeding supplements given to colonies. Trialling was conducted at Jebel, Romania between April 15 and May 4 2011 using 30 colonies which each received 1.4 l per week of supplemental feed sugar syrup with these substances added. Acacia honey production was assessed by weight at the end of May. Production was found to be significantly higher in the treatment group compared with the control (p<0.05) resulting, for the treatment group, in a predicted economic premium ranging between 9.38 and 22.06%
