Nutritional and prebiotic efficacy of the microalga Arthrospira platensis (spirulina) in honey bees

Vincent A Ricigliano,Michael Simone-Finstrom

doi:10.1007/s13592-020-00770-5

Vincent A Ricigliano, Michael Simone-Finstrom

Open Access

https://doi.org/10.1007/s13592-020-00770-5

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Abstract

We evaluated the microalga Arthrospira platensis (commonly called spirulina), as a pollen substitute for honey bees. Nutritional analyses indicated that spirulina is rich in essential amino acids and a wide variety of functional lipids (i.e., phospholipids, polyunsaturated fatty acids, and sterols) common in pollen. Feeding bioassays were used to compare dry and fresh laboratory-grown spirulina with bee-collected pollen and a commercial pollen substitute using sucrose syrup as a control. Diets were fed ad libitum as a paste to newly emerged bees in cages (10–13 cage replicates) and bees were sampled at days 5 and 10 for physiological and molecular measurements. Spirulina diets produced biomarker profiles (thorax weight, head protein content, and beneficial gut bacteria abundance) that were indicative of elevated nutritional states, meeting or exceeding the other diets in some metrics despite reduced consumption. Furthermore, spirulina diets led to significantly increased fat body lipid content and mRNA levels of the central storage lipoprotein vitellogenin. We conclude that spirulina has significant potential as a pollen substitute or prebiotic diet additive to improve honey bee health.

Highlights

To compensate for periods of forage scarcity or to bolster colony size prior to pollination services, beekeepers routinely feed pollen substitute (PS) diets to honey bees (Nabors 2000; Mattila and Otis 2006)
Our results indicate that spirulina has significant potential as a feed additive or pollen replacement based on its nutritional content and effects on nurse-aged worker bee physiology
While this assessment is based on experiments with laboratory-reared bees and as such provides a snapshot into effects on workers, the findings warrant further study on the impact of spirulinabased diets at the colony level

Summary

Introduction

To compensate for periods of forage scarcity or to bolster colony size prior to pollination services, beekeepers routinely feed pollen substitute (PS) diets to honey bees (Nabors 2000; Mattila and Otis 2006). PSs are generally considered a safe way to deliver protein to colonies since feeding bee-collected pollen is cost-prohibitive and difficult to standardize, can transmit disease, and can be contaminated by pesticides (Brodschneider and Crailsheim 2010). Vg expression levels are correlated with diet and landscape quality, making it a useful biomarker of individual (Alaux et al 2011; Frias et al 2015) and colony-level (Ricigliano et al 2018; Ricigliano et al 2019) nutritional status

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