The effects of zinc-methionine and Sel-Plex on the hypopharyngeal gland size, royal jelly yield and composition and the relative expression of hsp90 and trx gene in honey bees under heat stress

The aim of this study was to evaluate the effect of organic zinc and selenium on the antioxidant indices, acini size, royal jelly production, and relative expression of hsp90 and trx genes in honey bees under heat stress. Twenty five colonies were exposed to heat stress (42 °C for at least 4 h per day) and randomly divided into five treatments. Treatments were C), the control group receiving syrup without additives and other groups receiving syrup containing 2500 µg/L of zinc (T1), 5000 µg/L of zinc (T2), 500 µg/L selenium (T3), and 1000 µg/L selenium (T4). Organic zinc increased (P < 0.05), but selenium supplementation decreased (P < 0.05) the activities of thioredoxin peroxidase and catalase. Organic zinc and selenium supplements decreased (P < 0.05), the relative gene expression of hsp90 but increased (P < 0.05) gene expression of trx as compared to control. The lowest acini size was observed in C and the greatest acini size was observed in T2 (P < 0.05). Acini size increased (P < 0.05) as dose of organic zinc increased but not for selenium doses. It was concluded that supplementation of zinc at dose of 5000 µg/L and selenium at a dose of 500 µg /L has beneficial effects on producing royal jelly colonies.