Nutritional and prebiotic efficacy of the microalga Arthrospira platensis (spirulina) in honey bees Vincent A. Ricigliano, Michael Simone-Finstrom

To cite this version:

Vincent A. Ricigliano, Michael Simone-Finstrom. Nutritional and prebiotic efficacy of the microalga Arthrospira platensis (spirulina) in honey bees. Apidologie, 2020, 51 (5), pp.898-910. ￿10.1007/s13592- 020-00770-5￿. ￿hal-03221803￿

HAL Id: hal-03221803 https://hal.archives-ouvertes.fr/hal-03221803 Submitted on 10 May 2021

HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Apidologie (2020) 51:898–910 Original article * The Author(s), 2020 DOI: 10.1007/s13592-020-00770-5

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

Vincent A. RICIGLIANO, Michael SIMONE-FINSTROM

USDA ARS, Honey Bee Breeding, Genetics and Physiology Research, Baton Rouge, LA 70820, USA

Received 16 August 2019 – Revised 17 January 2020 – Accepted 7 April 2020

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.

Apis mellifera / nutrition / microbiota / microalgae / pollen substitute

1. INTRODUCTION or lentils. Early attempts at formulating PS diets failed to match the nutritional efficacy of pollen To compensate for periods of forage scarcity or and had low palatability (Standifer et al. 1973). to bolster colony size prior to pollination services, Soy products are common ingredients in PSs de- beekeepers routinely feed pollen substitute (PS) spite reports of potential anti-nutritional factors diets to honey bees (Nabors 2000; Mattila and such as toxic sugars (Barker 1977) and protease Otis 2006). PSs are generally considered a safe inhibitors (Liener 1994;Sagilietal.2005). Some way to deliver protein to colonies since feeding more recently developed commercial PSs appear bee-collected pollen is cost-prohibitive and diffi- to match the nutritional value of pollen cult to standardize, can transmit disease, and can (DeGrandi-Hoffman et al. 2010;DeJongetal. be contaminated by pesticides (Brodschneider and 2009); however, these diets have not been robust- Crailsheim 2010). These artificial diets consist of ly tested and their proprietary formulas confound a base protein derived from soy, yeast, egg, wheat, efforts to investigate the effects of individual com- ponents. Feeding PSs has become a common management practice as landscape compositions Electronic supplementary material The online version of this article (https://doi.org/10.1007/s13592-020-00770-5) shift to agriculturally intensive monocultures that contains supplementary material, which is available to may not meet the nutritional requirements of bees authorized users. (Naug 2009). PSs are increasingly used by US Corresponding author: V. Ricigliano, beekeepers in the fall and winter months leading [email protected] up to pollination of early crops such as almonds. Manuscript editor: David Tarpy Therefore, improving the effectiveness and Nutritional value of spirulina in honey bees 899 sustainability of PS diets can be considered im- palatability, and functional properties of pollen portant to modern beekeeping. in a sustainable formulation. Microalgae, which While the nutritional value of pollen is largely are mostly photosynthetic, unicellular, or simple attributed to its protein content and amino acid multicellular organisms, have recently gained composition (Crailsheim 1990; Brodschneider traction as a feed source for aquaculture and ter- and Crailsheim 2010), there has been compara- restrial livestock (Roy and Pal 2014;Odjadjare tively less focus on lipids as they relate to supple- et al. 2017; Lamminen et al. 2019), mental nutrition for bees. Pollen contains a wide including honey bees (Jehlík et al. 2019; variety of lipids and is particularly rich in Ricigliano 2020). Extensive nutritional and toxi- membrane-constituting phospholipids, fatty acids, cological evaluations have demonstrated the suit- and sterols (reviewed in Ischebeck 2016). Pollen ability of microalgal biomass as a feed additive or consumption leads to global changes in honey bee substitute for conventional protein sources tissue phospholipid composition. This pollen- (García et al. 2017; Caporgno and Mathys influenced phospholipid spectra and the preva- 2018). The rapid growth rates and biomass pro- lence of esterified polyunsaturated fatty acid duction of microalgae can enable them to outyield (PUFA) residues are strongly linked to abdominal conventional protein feed resources on an area vitellogenin (vg ) expression (Wegener et al. basis using non-arable land, mitigating some en- 2018). Vg is the major lipoprotein produced by vironmental burdens of intensive agriculture abdominal fat body cells and is central to brood (Forján et al. 2014; Tallentire et al. 2018). The production, life span regulation, oxidative stress blue-green microalga Arthrospira platensis is response, and overwintering (Amdam et al. 2003; grown on an industrial scale as a nutrition supple- Amdam et al. 2005). Vg expression levels are also ment for humans and livestock (Soni et al. 2017). correlated with diet and landscape quality, making This microalga, commonly called spirulina, is it a useful biomarker of individual (Alaux et al. considered a complete nutrition source and is rich 2011; Frias et al. 2015) and colony-level in essential amino acids, functional lipids, com- (Ricigliano et al. 2018; Ricigliano et al. 2019) plex , , and minerals nutritional status. (Ciferri 1983). While the nutritional efficacy of Pollen and nectar modulate bacterial commu- spirulina has been well documented in other ani- nities (microbiota) in the honey bee gut that influ- mals, their efficacy as a nutrition source for honey ence metabolism, immunity, and overall fitness bees is largely unkown. The objective of this (Engel et al. 2016; Kwong et al. 2017; Bonilla- study was to assess the potential of spirulina as a Rosso and Engel 2018). additives are nutrition supplement for honey bees during pe- used in some PS diets; however, there is little riods of pollen scarcity. evidence to support their effectiveness or estab- lishment when delivered as diet supplements 2. MATERIALS AND METHODS (Stephan et al. 2019). An alternative approach takes into consideration the pre biotic (Samal and 2.1. Honey bees (Apis mellifera L. )and Behura 2015) efficacy of a diet to stimulate experimental design growth and metabolism of endogenous microbio- ta that promote bee health (e.g., , Experiments were conducted in April–May ,andSnodgrasella ). Since bee- 2019 at the USDA ARS honey bee lab in Baton associated bacterial symbionts co-evolved with a Rouge, LA, USA. Newly emerged workers (< natural pollen diet (Kešnerová et al. 2017), micro- 24 h old) were obtained by incubating sealed biota abundance could be an informative metric to brood combs sourced from multiple healthy colo- evaluate extra-nutritive effects of artificial diets on nies at 35 °C and 50% RH. Bees were collected bee physiology (Ricigliano et al. 2017; Zheng into a single container, mixed thoroughly, then et al. 2018;Lietal.2019). randomly assigned to diet treatment cages. Pre- Development of PSs for honey bees should aim liminary trials were conducted to optimize deliv- to recapitulate the phytochemical profile, ery and consumption of spirulina diets (Online 900 V. A. Ricigliano, M. Simone-Finstrom resource 1, Figure S1). Using the optimized con- recalculated for the total diet consumed over ditions, two feeding tests were conducted using 24 h per bee. Drip feeders of 50% (w/v) sucrose cage as the unit of replication (50 bees/cage) to solution were provided to all cages. compare the effects of different diets. Test 1 eval- uated sucrose only, pollen, a commercial PS, and 2.3. Nutritional analysis dry spirulina, while the objective of test 2 was to assess the nutritional value of fresh, laboratory- 2.3.1. Amino acid content grown spirulina in parallel with the treatment groups from test 1. In test 1, 51 cages in total were Free amino acids in samples of pollen, PS, dry established for the 4 diet treatments (12–13 cages spirulina, and fresh spirulina were quantified by per treatment). In test 2, 52 cages in total were New England Peptide (Boston, MA, USA). Brief- established for the 5 diet treatments (10–12 cages ly, samples were subjected to vapor-phase acid per treatment). Physiological and molecular mea- hydrolysis, derivatization, and high-performance sures were made using pools of 10 bees collected liquid chromatographic (HPLC) determination of separately from each cage at day 5 and day 10. 15 amino acids based on chromatographic peak Dead bees were counted and removed from the identification and peak area quantification. This cages daily. hydrolysis method destroys cysteine, methionine, and tryptophan residues and, therefore, these com- 2.2. Diet preparation and consumption pounds are not included in the analysis.

Bees were fed ad libitum diets of pollen, com- 2.3.2. Lipidomic analysis mercial PS that lacks pollen, or spirulina (com- mercially sourced dry or fresh laboratory-grown). Lipid analysis of dry spirulina was performed Diets were mixed into a paste with 50% sucrose by Avanti Polar Lipids (Alabaster, AL, USA). (w/v) syrup containing 5% glycerol (v/v; to im- Modified Bligh and Dyer extractions (Bligh and prove pliability) and loaded into small troughs Dyer 1959) were performed with EquiSPLASH™ then stored at − 20 °C before use. Control cages Lipidomix™, and Lipidyzer™ standards (Avanti received sucrose syrup only. For the polyfloral Polar Lipids), and different chain lengths of pollen diet, mixed corbicular pollen pellets were phosphatidylglycerol, phosphatidylserine, and collected using entrance-mounted pollen traps in a phosphatidylinositol (Avanti Polar Lipids) were USDA ARS apiary in Baton Rouge and immedi- added as internal standards (IS). Total lipids were ately frozen upon until ready for use (Mogren dried then resolvated in 1 mL of 1:1 methylene et al. 2018). For the PS diet, a commercial plant- chloride:methanol. Samples were injected in trip- based protein supplement was used. The dry spi- licate without dilution for LC-MS analysis. The rulina diet consisted of commercially sourced dry methodology used was hydrophophilic interaction spirulinapowder.Thefreshspirulinadietusedin liquid chromatography (HILIC), which separates test 2 consisted of fresh harvested A. platensis lipids into classes and subclasses that span a nar- UTEX LB 2340 biomass that was grown in our row retention time window (Hines et al. 2017). A laboratory under standard conditions in Zarrouk standard of 18:1 cholesterol ester was used as an medium (Vonshak et al. 1983), rinsed in dH2O IS for stigmasterols and brassicasterols. Data are over a 30 μm filter, pressed to removed excess presented as ng/mg of sample. Values were calcu- water, and mixed with syrup as above. The lated using a point calibration determined by mul- amount of diet consumed by each cage was re- tiplying area ratio averages for the analyte to IS corded then the diet was refreshed with 3 small and multiplying by the concentration of IS. troughs (~ 700 mg) of diet paste daily. The weight loss by diet samples maintained in a cage without 2.4. Nutritional assimilation measures bees was measured to determine the daily evapo- ration rate for each diet. Diet consumption in each Bees were dissected into head, thorax (includ- cage was adjusted for daily moisture loss and ing legs and wings) and abdomen, and parts were Nutritional value of spirulina in honey bees 901 pooled into groups of 10. Average thorax weight 3. RESULTS per cage (test 2) was determined by drying to a constant weight (60 °C for ~ 48 h) and recording 3.1. Nutritional analyses to the nearest 0.1 mg. Average head protein con- tent per cage (test 2) was determined using spec- We measured the abundance of 15 amino acids trophotometric protein quantification (Sagili et al. (AAs), including 8 essential AAs. The content of 2005). Average fat body mass per cage (test 1) each essential AA detected in spirulina met or was determined using abdomens with guts re- exceeded that of pollen with the exception of moved and the ether extraction method described histidine and lysine (Figure 1), which were twice in (Wilson-Rich et al. 2008). as high in pollen. Pollen substitute (PS) had the lowest essential AA content with the exception of 2.5. Vitellogenin (vg ) expression and gut histidine, which was the same as spirulina. The bacteria abundance AA profiles of dry and fresh spirulina were highly similar. For gene expression and bacterial abundance Lipidomic analysis of spirulina identified and measures (test 1), pools of 10 abdomens per cage quantified 13 subclasses of phospholipids (309 with whole guts intact were homogenized in 2 mL species), 3 subclasses of neutral lipids (447 spe- lysis buffer (1.2 M guanidine thiocyanate, 0.6 M cies), and two subclasses of sterols (37 species). ammonium thiocyanate). Samples were centri- The lipid categories were obtained by summing fuged and total RNA was extracted from 300 μL the levels of individual molecular species within of supernatant using a GeneJet RNA Purification each type (Table I). The levels of each species are Kit (Thermo Fisher Scientific). cDNA was syn- listed in detail in (Online resource 2). thesized from 1 μg of DNaseI-treated RNA using Phosphatidylglycerol, sphingomyelin, and a RevertAid First Strand cDNA Synthesis Kit lysophosphatidylglycerol were the major phos- (Thermo Fisher Scientific). Quantitative PCR pholipid subclasses, accounting for 62.4% of the (qPCR), carried out in triplicate with previously total lipids. The sterol content (sigmasterol + published primer pairs and cycling conditions, brasssicasterol) was 9.4%. The fatty acids 16:0, was used to determine the relative expression 18:2, 18:1, 18:0, 18:3, 20:0, 20:1, 20:3, 20:5, levels of honey bee genes (vg , vg-like-A , vg- 22:2, 24:0, and 22:6 were predominant in the total like-B ) (Salmela et al. 2016) and species-specific esterified fatty acids (Online resource 2). bacterial 16S rRNA genes (Lactobacillus Firm 5 , Bifidobacterium , Snodgrassella )(Kešnerová 3.2. Diet consumption et al. 2017) across treatments using honey bee actin for normalization (Alaux et al. 2011). Food consumption (corrected for evaporative loss) in test 1 was influenced by diet (F 2, 72 = 2.6. Statistical analyses 241.9, P < 0.001) and age (F 1, 72 =236.8,P < 0.001), but not their interaction (P =0.69).Cu- The effects of diet treatments and bee age on mulative consumption was highest for the pollen food consumption, thorax weight, fat body mass, diet (65.37 mg/bee) and lowest for the dry spiru- head protein, and vg expression were evaluated lina diet (40.04 mg/bee) (Figure 2a). Test 2 con- using two-way ANOVA. Kaplan-Meier survival sumption was influenced by diet (F 3, 76 =36.92, estimates were used to determine the effect of diet P < 0.001), age (F 1, 76 = 210. 20, P <0.001),and on life span. The effects of diet treatments on gut their interaction (F 3, 76 =9.88, P < 0.001). Cu- bacteria abundance were evaluated using one-way mulative consumption was highest for the pollen ANOVA. Variables with deviations from normal- diet (39.03 mg/bee) and lowest for the dry spiru- ity were re-evaluated after log transformation. The lina diet (28.41 mg/bee) (Figure 2b). Mortality Tukey HSD post hoc test was used to compare was less than 3% overall for test 1 and less than different treatment groups. Analyses were con- 5% overall in test 2, so mortality was negligible ducted in JMP v11 and Prism v7. for all treatments in the course of the study. 902 V. A. Ricigliano, M. Simone-Finstrom

Figure 1. Amino acid content of different protein sources: bee-collected pollen, pollen substitute (PS), dry spirulina, and fresh spirulina. Essential amino acids are emphasized.

However, for the sucrose group, mortality was Soluble head protein content was influenced by higher than the rest of the treatments in test 2 diet (F 4, 94 = 111.2, P < 0.001) and age (F 1, 94 = and no differences were noted in Trial 1 (Online 21.14, P < 0.001) but not their interaction (P = resource 1, Figure S2). These results were consis- 0.356). Protein levels were highest in bees fed PS tent with preliminary tests to assess spirulina tox- and lowest in bees fed only sucrose. There were icity to bees, which revealed no significant differ- no differences in head protein content among ence in mortality compared with sucrose-fed con- pollen and spirulina diets (Figure 3b). trol (Online resource 1, Figure S3). Fat body mass was influenced by diet (F 3, 90 = 57.0, P < 0.001), age (F 1, 90 = 41.98, P <0.001), and their interaction (F 3, 90 =9.03, P <0.001). 3.3. Nutrient assimilation measures Fat body mass at day 10 was highest in bees fed pollen and dry spirulina (Figure 4). Thorax weight was influenced by diet (F 4, 94 =31.51, P < 0.001) and age (F 1, 94 =341.5, P < 0.001), but not their interaction (P =0.200). 3.4. Vitellogenin (vg ) and vg-like expression Thorax weight was highest in bees fed dry spiru- lina (Figure 3a). Similarly, preliminary feeding Vitellogenin (vg ) expression was influenced tests with a broader range of consumption values by diet (F 3, 92 =321.6,P < 0.001) and age (F 1, revealed a strong positive correlation between 92 = 10.88, P = 0.001) but not their interaction spirulina diet consumption and dried thorax (P =0.950). Vg expression was highest in bees 2 weight (F 1, 58 = 69.7, P < 0.001; r = 0.546) fed PS and lowest in bees fed sucrose only. There (see Online resource 1 Figure S1c). was no difference between bees fed pollen or Nutritional value of spirulina in honey bees 903

Table I. Lipidomic analysis of spirulina. See Online resource 2 for fatty acid compositions of the molecular species in each lipid subclass

Concentration (ng/mg) Percent composition

Phospholipids Phosphatidylglycerol 946.16 43.03 Lysophosphatidylglycerol 222.83 10.14 Sphingomyelin 203.59 9.26 133.95 6.09 Phosphatidylethanolamine 119.32 5.43 Phosphatidylinisitol 37.66 1.71 Lysophosphatidylcholine 12.51 0.57 Phsophatidylserine 4.91 0.22 Lysophosphatidylinisitol 2.01 0.09 Lysophosphatidylethanolamine 1.81 0.08 Ceramide 0.79 0.04 Dihydroceramide 0.62 0.03 Hexosylceramide 0.53 0.02 Neutral lipids Triacylglycerol 152.30 6.93 Diacylglycerol 124.95 5.68 Cholesterol ester 27.92 1.27 Sterols Stigmasterol 138.39 6.29 Brasssicasterol 68.39 3.11 spirulina (Figure 5a). Vg-like-A expression was 25.48, P < 0.001; Figure 6b). Snodgrasella abun- influenced by diet (F 3, 92 = 166.0, P <0.001), dance was highest in bees fed spirulina and lowest age (F 1, 92 =66.36,P < 0.001), and their inter- in bees fed pollen substitute (F 3, 46 =5.09,P < action (F 3, 92 =3.96,P =0.010). Vg-like-A ex- 0.001; Figure 6c). pression was highest in bees fed PS at day 10 and lowest in bees fed sucrose only (Figure 5b). Vg- 4. DISCUSSION like-B expression was influenced by diet (F 3, 92 =32.98,P <0.001),age(F 1, 92 =39.49,P < This study assessed the nutritional value and 0.001), and their interaction (F 3, 92 = 11.74, P < functional properties of spirulina in honey bees. 0.001). Vg-like-B expression was highest in bees We chose to evaluate spirulina due to its well- fed spirulina at day 10 (Figure 5c). documented nutritional and non-toxic effects in a variety of animals including humans (Soni et al. 3.5. Gut bacteria abundance 2017). The choice of microalgae species likely impacts animal health based on its chemical com- Lactobacillus Firm 5 abundance was highest position, including amino acid content, lipid con- in bees fed spirulina and lowest in bees fed pollen tent, and cell wall structure (Caporgno and substitute or sucrose (F 3, 46 = 31.89, P < 0.001; Mathys 2018). Our results indicate that spirulina Figure 6a). Bifidobacterium abundance was has significant potential as a feed additive or pol- highest in bees fed pollen and spirulina and lowest len replacement based on its nutritional content in bees fed pollen substitute and sucrose (F 3, 46 = and effects on nurse-aged worker bee physiology. 904 V. A. Ricigliano, M. Simone-Finstrom

Figure 2. Diet consumption (milligrams per bee) by caged honey bees after 5 and 10 days. a Test 1, n =12–13 cages. b Test 2, n =10–12 cages. Each point represents an independent cage. Black horizontal lines indicate the mean. Different letters indicate Tukey HSD P <0.05.

While this assessment is based on experiments contained a proprietary blend of plant-based pro- with laboratory-reared bees and as such provides teins, which may have conferred increased bio- a snapshot into effects on workers, the findings availability relative to the polyfloral pollen diet warrant further study on the impact of spirulina- tested. The AA content of commercially sourced based diets at the colony level. and lab-grown spirulina were highly similar, indi- Since honey bees cannot synthesize arginine, cating that biomass grown under different condi- histidine, lysine, tryptophan, phenylalanine, me- tions can reproducibly support the AA require- thionine, threonine, leucine, isoleucine, and va- ments of honey bees. This was confirmed by line, it is critical that these AAs are present in elevated thorax weights and head protein the diet (De Groot 1953). AAs are obtained from levels in spirulina-fed bees relative to sucrose pollen and supplemented by feeding PS diets. The control. Head protein levels are considered a essential AAs detected in spirulina met or biomarker of nutritional status as pollen con- exceeded the other diets tested, with the exception sumption by workers leads to increased protein of histidine and lysine, which were twice as high synthesis in head hypopharengeal glands that in pollen. PS had the lowest essential AA content feed the colony via proteinaceous secretions but produced higher head protein levels than pol- (Crailsheim 1990; DeGrandi-Hoffman et al. len or spirulina diets. The discrepancy between 2010). Taken together, the results suggest that PS- and spirulina-fed bees could be attributed to spirulina could be incorporated as a sole pro- higher consumption of PS. However, consump- tein source in future PS diets to support brood tion of the pollen diet was higher than PS. The PS production in colonies. Nutritional value of spirulina in honey bees 905

Figure 3. Protein assimilation in bees fed different diets after 5 and 10 days (n =10–12 cages). a Thorax weight as a proxy for flight muscle development. b Soluble head protein as a proxy for hypopharyngeal gland development. Each point represents an independent cage. Black horizontal lines indicate the mean. Different letters indicate Tukey HSD P <0.05.

Phospholipids are the major lipid components membrane lipids and lipoproteins. FAs are classified detected in honey bee tissues and pollen. Dietary based on their degree of saturation (double versus phospholipids contain esterified fatty acid (FA) res- single bonds), which influence the biochemical idues, which are hydrolyzed during digestion then functions of lipids they comprise. Linoleic acid reincorporated into cellular macromolecules such as (LA, 18:2) and alpha-linoleic acid (ALA, 18:3) are

Figure 4. Fat body mass of bees fed different diets at 5 and 10 days (n =12–13 cages). Each point represents an independent cage. Black horizontal lines indicate the mean. Different letters indicate Tukey HSD P <0.05. 906 V. A. Ricigliano, M. Simone-Finstrom

Figure 5. Relative mRNA expression levels of vitellogenin (vg )andvg-like gene homologs in bees fed different diets at day 5 and day 10 (n =12–13 cages). Each point represents an independent cage. Black horizontal lines indicate the mean. Different letters indicate Tukey HSD P <0.05. two major polyunsaturated fatty acids (PUFAs) that pollen consumption, supporting its use as a biomark- are considered essential for higher animals (Hulbert er of diet quality and nutritional status (Alaux et al. et al. 1999), including bees (Avni et al. 2014;Arien 2011; López-Uribe et al. 2020). Our results show et al. 2015). Spirulina has a broad diversity of phos- that fat body mass and Vg mRNA levels in pholipid molecular species incorporating LA, ALA, spirulina-fed bees matched that of pollen-fed bees. and longer chain PUFAs such as eicosapentaenoic Pollen and spirulina diets led to higher fat body acid (EPA, 20:5) and docosahexaenoic acid (DHA, masses than PS, which produced the highest Vg 22:6) (Online resource 2). Pollen consumption leads mRNA levels. The PS diet also led to higher expres- to global reconstruction of honey bee tissue phos- sion levels of vg-like-A , which likely plays similar pholipid molecular species, and the abundance of roles to vg (Salmela et al. 2016). However, vg and esterified PUFAs is positively correlated with fat vg-like-A proteins contain a large lipid-binding do- body expression of vg (Wegener et al. 2018). Vg main (Salmela et al. 2016) and it remains to be is a highly abundant lipoprotein produced in fat determined if dietary lipid composition impacts their body cells with central storage and regulatory func- function. Intriguingly, mRNA levels of vg-like-B tions (Amdam et al. 2003; Amdam et al. 2005). Vg were highest in 10-day-old spirulina-fed bees. Func- itself is regulated at the mRNA and protein level by tional understanding of this vg homolog is limited Nutritional value of spirulina in honey bees 907

Figure 6. Relative core gut bacteria abundance in bees fed different diets at day 10 (n =12–13 cages). Each point represents an independent cage. Black horizontal lines indicate the mean. Different letters indicate Tukey HSD P < 0.05. but it has been associated with the life span– Gut bacteria fermentation products act as signaling regulating properties of vg (Salmela et al. 2016) molecules, influencing central physiological pro- Bacterial abundance of core was cesses in honey bees (Zheng et al. 2017). Spirulina significantly increased by a spirulina diet, which biomass stimulates the growth of Lactobacillus matched or exceeded the prebiotic effects of pollen and other (Parada et al. 1998), and PS, respectively. These results are consistent which can competitively exclude pathogenic bac- with the prebiotic potential of microalgae as a teria via pH reduction (Douglas 2015). These re- nutrition supplement in other systems (de Jesus sults suggest that incorporating spirulina into PS Raposo et al. 2016). Lactobacillus spp and diets as a prebiotic additive could promote bee Bifidobacterium spp are ubiquitous fermentative health by stimulating the abundance and metabo- constituents of animal microbiota, including bees. lism of beneficial gut bacteria. The bee-specific gut symbiont Snodgrassella alvi Overall, the major findings that spirulina diets is non-fermentative but participates in syntropic resulted in nutritional physiology measures that were (-sharing) interactions with fermentative nearly equal to a pollen-based diet show promise for community members (Kešnerová et al. 2017). the development of this microalga, and potentially 908 V. A. Ricigliano, M. Simone-Finstrom other microalgal species, as a nutrition supplement Apis mellifera / nutrition / microbiote / microalgue / for honey bees. Spirulina consumption was less than substitut de pollen that of pollen or PS but resulted in bees with equiv- Ernährungsphysiologische und präbiotische Effekte alent fat body mass and increased thorax weight, der Mikroalge Arthrospira platensis (spirulina) bei respectively. This indicates that the nutritional value Honigbienen of spirulina is certainly at least sufficient for honey bees and its incorporation into future PS diets may Apis mellifera / Ernährung/ Mikrobiota/ Mikroalge/ be a sustainable solution to improve various aspects Pollenersatz of honey bee health. ACKNOWLEDGMENTS

We thank the members of the USDA ARS Honey REFERENCES Bee Breeding, Genetics, and Physiology lab for their technical support and stimulating discussions. We fur- ther thank the reviewers for helpful comments and Alaux, C., Dantec, C., Parrinello, H., Le Conte, Y. (2011) suggestions that improved the manuscript. Mention of Nutrigenomics in honey bees: digital gene expression trade names or commercial products in this publication analysis of pollen’s nutritive effects on healthy and is solely for the purpose of providing specific informa- varroa-parasitized bees. BMC Genomics 12 ,496 tion and does not imply recommendation or endorse- Amdam, G.V., Norberg, K., Hagen, A., Omholt, S.W. ment by the US Department of Agriculture. USDA is an (2003) Social exploitation of vitellogenin, Proc Natl Acad Sci 100 ,1799–1802. equal opportunity provider and employer. Amdam, G.V., Norberg, K., Omholt, S.W., Kryger, P., Lourenço, A.P., Bitondi, M.M.G., Simões, Z.L.P. AUTHORS’ CONTRIBUTIONS (2005) Higher vitellogenin concentrations in honey bee workers may be an adaptation to life in temperate climates. Insect Soc 52 ,316–319 VAR conceived this research and designed the Arien, Y., Dag, A., Zarchin, S., Masci, T., Shafir, S. (2015) experiments. VAR and MSF performed the exper- Omega-3 deficiency impairs honey bee learning. Proc iments and analyzed the data. VAR and MSF Natl Acad Sci 112 , 15761–15766. wrote the paper. Both authors read and approved Avni, D., Hendriksma, H.P., Dag, A., Uni, Z., Shafir, S. the final manuscript. (2014) Nutritional aspects of honey bee-collected pol- len and constraints on colony development in the east- ern Mediterranean. J Insect Physiol 69 ,65–73. OPEN ACCESS Barker, R.J. (1977) Some carbohydrates found in pollen and pollen substitutes are toxic to honey bees. J Nutr This article is licensed under a Creative Commons 107, 1859–1862. Attribution 4.0 International License, which permits Bligh, E.G., Dyer, W.J. (1959) A rapid method of total lipid use, sharing, adaptation, distribution and reproduction extraction and purification. Can J Biochem Physiol 37 , in any medium or format, as long as you give appropri- 911–917. ate credit to the original author(s) and the source, pro- Bonilla-Rosso, G., Engel, P., (2018) Functional roles and vide a link to the Creative Commons licence, and indi- metabolic niches in the honey bee gut microbiota. Curr cate if changes were made. The images or other third Opin Microbiol 43, 69–76. party material in this article are included in the article's Brodschneider, R., Crailsheim, K. (2010) Nutrition and Creative Commons licence, unless indicated otherwise health in honey bees. Apidologie. 41 ,278–294. in a credit line to the material. If material is not included Caporgno, M.P., Mathys, A. (2018) Trends in microalgae in the article's Creative Commons licence and your incorporation into innovative food products with po- intended use is not permitted by statutory regulation or tential health benefits. Front Nutr. DOI: https://doi. org/10.3389/fnut.2018.00058 exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view Ciferri, O., (1983) Spirulina, the edible . Microbiol Rev 47 ,551–578. a copy of this licence, visit http://creativecommons. org/licenses/by/4.0/. Crailsheim K (1990) The protein balance of the honey bee worker. Apidologie 21 ,417–429. De Groot, A.P. (1953) Protein and amino acid requirements Efficacité nutritionnelle et prébiotique de la microalgue of the honeybee (Apis mellifica L.). Physiol Comp Arthrospira platensis (spiruline) chez l’abeille Oecol 3 ,1–83 Nutritional value of spirulina in honey bees 909 de Jesus Raposo, M., de Morais, A., de Morais, R. (2016) Li, J., Heerman, M.C., Evans, J.D., Rose, R., Li, W., et al. Emergent sources of prebiotics: seaweeds and (2019) Pollen reverses decreased lifespan, altered nu- microalgae. Mar Drugs https://doi.org/10.3390 tritional metabolism and suppressed immunity in hon- /md14020027. ey bees (Apis mellifera ) treated with . J Exp De Jong D., da Silva E.J., Kevan P.G., Atkinson J.L. (2009) Biol: https://doi.org/10.1242/jeb.202077 . Pollen substitutes increase honey bee haemolymph Liener, I.E. (1994) Implications of antinutritional compo- protein levels as much as or more than does pollen, J nents in soybean foods. Crit Rev Food Sci Nutr 34, Apic Res 48 ,34–37. 31–67. DeGrandi-Hoffman, G., Chen, Y., Huang, E., Huang, M.H. López-Uribe, M.M., Ricigliano, V.A, Simone-Finstrom, M. (2010) The effect of diet on protein concentration, (2020) Defining pollinator health: A holistic approach hypopharyngeal gland development and virus load in based on ecological, genetic, and physiological factors. worker honey bees (Apis mellifera L.). J Insect Physiol Ann Rev Anim Biosci 8 ,269–294. – 56 , 1184 1191 Mattila, H.R., Otis, G.W. (2006) Influence of pollen diet in Douglas, A.E. (2015) Multiorganismal insects: diversity spring on development of honey bee (Hymenoptera: and function of resident . Annu Rev Apidae) colonies. J Econ Entomol 99 ,604–613. – Entomol 60 ,17 34. Mogren, C. L., Margotta, J., Danka, R. G., Healy, K. Engel, P., Kwong, W.K., McFrederick, Q., Anderson, K.E., (2018). Supplemental carbohydrates influence abiotic Barribeau, S.M., et al. (2016) The bee : stress resistance in honey bees. J Apic Res 57 ,682– impact on bee health and model for evolution and 689. ecology of host-microbe interactions. mBio DOI: Nabors, R. (2000) The effects of spring feeding pollen https://doi.org/10.128/mBio.02164-15 substitute to colonies of Apis mellifera . Am Bee J Forján, E., Navarro, F., Cuaresma, M., Vaquero, I., Ruíz- 140 ,322–323. Domínguez, M.C., et al. (2014) Microalgae: fast- Naug, D. (2009) Nutritional stress due to habitat loss may growth sustainable green factories. Crit Rev Environ – explain recent honeybee colony collapses. Biol Sci Tech 45 ,1705 1755. Conserv 142 ,2369–2372. Frias, B.E.D, Barbosa, C.D., Lourenço, A.P. (2015) Pollen Odjadjare, E.C., Mutanda, T., Olaniran, A.O. (2017) Poten- nutrition in honey bees (Apis mellifera ): impact on – tial biotechnological application of microalgae: a crit- adult health. Apidologie 47 ,15 25. ical review. Crit Rev Biotechnol 37 ,37–52. García, J.L., de Vicente, M., Galán, B. (2017) Microalgae, Parada, J.L., Zulpa de Caire, G., Zaccaro de Mulé, M.C., old sustainable food and fashion nutraceuticals. – Storni de Cano, M.M. (1998) Lactic acid bacteria Microb Biotechnol 10 , 1017 1024. growth promoters from Spirulina platensis . Int J Food Hines, K.M., Herron, J., Xu, L. (2017) Assessment of Microbiol 45 ,225–228. altered lipid homeostasis by HILIC-ion mobility-mass – Ricigliano, VA. (2020) Microalgae as a promising and spectrometry-based lipidomics. J Lipid Res 58 ,809 sustainable nutrition source for managed honey 819. bees. Arch Insect Biochem Physiol 104 , e21658. Hulbert, A.J., Turner, N., Storlien, L.H., Else, P.L. (1999) Ricigliano, V.A., Fitz, W., Copeland, D.C., Mott, B.M., Dietary fats and membrane function: implications for Maes, P., et al. (2017) The impact of pollen consump- metabolism and disease. Biol Rev Camb Philos Soc – tion on honey bee (Apis mellifera ) digestive physiolo- 80 ,155 169. gy and metabolism. Arch Insect Biochem Ischebeck, T. (2016) Lipids in pollen - They are different. Physiol 96 , e21406–14. – Biochim Biophys Acta 1861 ,1315 1328. doi: Ricigliano, V.A., Mott, B.M., Floyd, A.S., Copeland, D.C., https://doi.org/10.1016/j.bbalip.2016.03.023. Carroll, M.J., et al. (2018) Honey bees overwintering Jehlík, T., Kodrík, D., Krištůfek, V., Koubová, J., Sábová, in a southern climate: longitudinal effects of nutrition M., et al. (2019). Effects of Chlorella sp. on biological and queen age on colony-level molecular physiology characteristics of the honey bee Apis mellifera . and performance. Sci Rep doi: https://doi.org/10.1038 Apidologie 50 , 564-577. /s41598-018-28732-z. Kešnerová, L., Mars, R.A.T., Ellegaard, K.M., Troilo, M., Ricigliano, V.A., Mott, B.M., Maes, P.W., Floyd, A.S., Fitz, Sauer, U., Engel, P. (2017) Disentangling metabolic W., et al (2019) Honey bee colony performance and functions of bacteria in the honey bee gut. PLoS Biol health are enhanced by apiary proximity to US Con- https://doi.org/10.1371/journal.pbio.2003467. servation Reserve Program (CRP) lands. Sci Rep doi: Kwong, W.K., Mancenido, A.L., Moran, N. A. (2017) https://doi.org/10.1038/s41598-019-41281-3. stimulation by the native gut microbi- Roy, S.S., Pal, R. (2014) Microalgae in aquaculture: a ota of honey bees. R Soc Open Sci https://doi. review with special references to nutritional value org/10.1098/rsos.170003. and fish dietetics. Proc Zool Soc 68 ,1–8. Lamminen, M., Halmemies-Beauchet-Filleau, A., Sagili, R.R., Pankiw, T., Zhu-Salzman, K. (2005) Effects of Kokkonen, T., Jaakkola, S., Vanhatalo, A. (2019) Dif- soybean trypsin inhibitor on hypopharyngeal gland ferent microalgae species as a substitutive protein feed protein content, total midgut protease activity and sur- for soya bean meal in grass silage based dairy cow vival of the honey bee (Apis mellifera L.). J Insect diets. Anim Feed Sci Tech 247 ,112–126. Physiol 51 ,953–957. 910 V. A. Ricigliano, M. Simone-Finstrom

Salmela, H., Stark, T., Stucki, D., Fuchs, S. (2016) Ancient Vonshak, A., Boussiba, S., Abeliovich, A., Richmond, A. duplications have led to functional divergence of (1983) Production of spirulina biomass: maintenance vitellogenin-like genes potentially involved in inflam- of monoalgal culture outdoors. Biotechnol Bioeng 25 , mation and oxidative stress in honey bees. Genome 341–349. Biol Evol 8 , 495-506. Wegener, J., Jakop, U., Schiller, J., Müller, K. (2018) The Samal, L., Behura, N.C. (2015) Prebiotics: an emerging membrane phospholipid composition of honeybee nutritional approach for improving gut health of live- (Apis mellifera ) workers reflects their nutrition, fertil- stock and poultry. Asian J Anim VetAdv 10 ,724–739. ity, and vitellogenin stores. Insect Soc 65 ,381–391. Soni, R.A., Sudhakar, K., Rana, R.S. (2017) Spirulina – Wilson-Rich, N., Dres, S.T., Starks, P.T. (2008) The ontog- from growth to nutritional product: a review. Trends in eny of immunity: development of innate immune Food Sci Technol 69 ,157–171. strength in the honey bee (Apis mellifera ). J Insect – Standifer, L.N., Haydak, M.H., Mills, J.P., Levin, M.D. Physiol 54 ,1392 1399. (1973) Influence of pollen in artificial diets on food Zheng, H., Powell, J.E., Steele, M.I., Dietrich, C., Moran, consumption and brood production in honey bee col- N.A. (2017) Honeybee gut microbiota promotes host onies. Am Bee J 113 ,94–95. weight gain via bacterial metabolism and hormonal – Stephan, J.G., Lamei, S., Pettis, J.S., Riesbeck, K., de signaling. Proc Natl Acad Sci 114 ,4775 4780. Miranda, J.R., Forsgren, E. (2019) Honeybee-specific Zheng, H., Steele, M.I., Leonard, S.P., Motta, E.V.S., lactic acid bacterium supplements have no rffect on Moran, N.A. (2018) Honey bees as models for gut American foulbrood-infected honeybee colonies. Appl microbiota research. Lab Anim 47 ,317–325. Environ Microbiol 85 ,283–14. Tallentire, C.W., Mackenzie, S.G., Kyriazakis, I. (2018) Publisher’s note Springer Nature remains neutral Can novel ingredients replace soybeans and reduce with regard to jurisdictional claims in published maps the environmental burdens of European livestock sys- tems in the future? J Cleaner Prod 187 ,338–347. and institutional affiliations.