Influence of the summer feeding by carbohydrates on catalase activity in honey bees
Authors: Karavan Volodymyr , Kachmaryk Diana , Cherevatov Volodymyr , Panchuk Irina , Yazlovytska Liudmyla 
Published: July 2021

The nutritional composition of rations determines the strength of honey bee families. Feeding with various carbohydrate solutions is widely used in beekeeping. The form of carbohydrate intake in insects can adversely affect their health, leading to redox imbalances. Catalase activity (CAT) is a marker of oxidative stress. It was investigated the catalase activity in foraging bees Apis mellifera during their summer feeding with carbohydrates in the field after grass flowering. The research was perfomed on a private apiary in Chernivtsi region with the local bees (hybrids of Carpathian, Ukrainian steppe and Caucasian breeds). 32 bee colonies, eight experimental groups, were fed various carbohydrates for four days. These are 30 % and 60 % sugar solution, a mixture of honey and 60 % sugar solution (2: 3), without feeding, 30 % glucose and fructose solutions, a mixture of 15 % glucose and fructose solutions (1: 1), a mixture of 30 % fructose solutions glucose (1: 1). Then all bees were fed with 30 % sugar solution. CAT activity was determined in the head, thorax and abdomen of bees by Aebi method with modifications. The highest CAT activity was detected when using 30 % sugar solution for insect feeding. While doubling the sugar concentration and adding honey to the sugar syrup reduced the activity of this enzyme in all bee tagmas. Feeding the colonies with 30 % solutions of glucose or fructose also decreased CAT activity. The cessation of additional feeding decreased the CAT activity in abdomen tissues. It should be noted that the 60 % concentration of sugar, which results equimolar amount of monosaccharides by hydrolysis, differently affects the CAT activity in the tissues of the head and thorax. Decrease of CAT activity is observed on a diet with disaccharide, and this activity does not change on a diet with an equimolar mixture of monosaccharides. At the same time, two fold reducing the sugars concentration (30 % sugar compared to 15 % glucose + 15 % fructose) has the opposite effect – a decrease of enzyme activity in head tissues on an equimolar mixture of monosaccharides and no changes in thorax tissues. Conclusions. It was shown that feeding bee colonies in the period of cessation of the main honey plants flowering with 30 % sugar solution increased the CAT activity in foraging bees. Feeding with 30 % solutions of monosaccharides (glucose, fructose) and 60 % solution of sugar led to decrease of enzyme activity in all studied tagmata (head, thorax, abdomen) of bees. The tagmaspecific responce to various types of a carbohydrate diet in bees was found: in the abdominal tissues of all experimental groups there was a decrease of catalase activity compared to feeding with 30 % sugar solution (preparatory stage), while in the tissues of the thorax and head CAT activity depended on the type of carbohydrate diet. It was demonstrated that the form of carbohydrate intake (disaccharide or equimolar mixture of monosaccharides) affects the CAT activity in the tissues of the head and thorax of insects.