Effects of the enterobacteria Bombella intestini on the nutritional metabolism of Apis mellifera
Author of the article:? ZHANG Wei, WANG Hong-Fang, XU Bao-Hua
Author's Workplace：College of Animal Science and Technology, Shandong Agricultural University, Tai’an 271018, China
Key Words：Apis mellifera; intestinal bacteria Bombella intestini; aseptic worker bees; nutrient metabolism
Abstract：
[Objectives] To investigate the effects of the enterobacterium Bombella intestini on the nutritional metabolism of Apis mellifera. [Methods] A total of 300 aseptic new bees were cultured using the aseptic worker bee model and randomly divided into 2 groups with 3 replicates per group and 50 new bees per replicate. The control group (CK) was fed 40% sterile sucrose solution, and the experimental group (BI) was fed 40% sucrose solution containing 106cfu/ml of B. intestini. Both groups were also fed sterile pollen and sterile deionized water. The bees were fed every day and their body weight, and the amount of sugar and pollen consumed, were recorded. On day 9, individual bees were sampled to determine their body composition, hemolymph biochemical indexes and the expression of genes related to nutrient metabolism. [Results] The results showed that the average daily sugar intake of the BI group was significantly higher than that of the CK group (P < 0.05), however, there was no significant difference in the body weight of the two groups (P > 0.05). The dry matter and lipid content of the BI group were significantly lower than those of the CK group (P < 0.05). However, the ash content of the BI group was significantly higher than that of the CK group (P< 0.05). The crude protein content of the BI group was slightly higher than that in CK group, whereas its carbohydrate content was slightly lower; both these differences were not statistically significant. The amounts of total protein (TP), triglyceride (TG), cholesterol (TCHO) and high-density lipoprotein (HDL) in hemolymph, were significantly lower in the BI group than in the CK group (P < 0.05). CytB, CytC, Vg, ILP and LnR were significantly up-regulated in the BI group. Since CytB and CytC are mitochondrial proteins involved in mitochondrial biological oxidation, their up-regulation suggests enhanced catabolism. [Conclusion] In conclusion, B. intestini can improve bees' appetite, stimulate feeding, increase body nutrient reserves and promote the catabolism of nutrients.