Nutritional efficacy of different diets supplemented with microalga Arthrospira platensis (spirulina) in honey bees (Apis mellifera)

In honey bees, food, gut microorganisms, and their nestmates may contribute to the health status of newly emerged worker bees. However, relatively little data are available regarding the extent to which supplemental protein feeding impacts bee colony health and mortality. The present research compared the efficacy of different diets supplements, i.e., bee pollen, ajeena (commercially available pollen substitute), and date paste either alone or admixed with varying percentages of microalga Arthrospira platensis (spirulina) for caged honey bees (Apis mellifera jemenitica). In addition, to investigate diet preference and mortality percentage in honey bees, the physicochemical analysis of these diets were also performed. Our results indicated that the honey bees consumed bee pollen (11.51 ± 2.22 mg/bee) and ajeena diet (10.68 ± 1.29 mg/bee) significantly higher than other diets.In contrast, the maximum consumption was 4.68 ± 2.82 mg/bee for date paste admixed with 2.5% spirulina than date paste diet only (2.41 ± 0.91 mg/bee). In addition, the mortality percentage was significantly lower when bees fed pollen (56.67% ± 3.88%) and ajeena diet (39.33% ± 2.08%) in comparison to combination with spirulina supplement. Overall, the mean maximum diet consumption for ajeena was 15.72 ± 3.65 mg/bee followed by bee pollen diet (11.97 ± 2.41 mg/bee) and date paste (2.08 ± 0.94 mg/bee), respectively, resulting mean percentage of mortality of 13.37% ± 3.77%. Physicochemical analysis revealed that glucose and fructose were higher in the date paste diet. In contrast, total sugar content, sucrose, and protein content were higher in the ajeena diet. Future research is needed to determine the impact of diet supplementation with spirulina on colony health and bee physiology.