OVERVIEW
THE HISTORICAL PRACTICE OF LIPID / FATTY ACID SUPPLEMENTATION IN THE PREPARATION OF POLLEN SUPPLEMENTS
FINDING A PATH TO SUPPLEMENTAL OPTIMIZATION
Historical Methodology
As a common practice, beekeepers and manufacturers have provided the lipid fraction of pollen supplements with the addition of Canola oil and/or Corn Oil (High omega 6 oils) and more recently, Borage Oil (24-methylene cholesterol source – High Omega 6/9 oil).
Our Questions:
· Does this practice provide the fatty acid profiles required for optimum honeybee reproduction and metabolic health?
· How does this practice align with the fatty acid profiles found in floral pollen?
· Are there detrimental effects to the colony when the fatty acid profiles of pollen are not respected?
· Are we missing a practical opportunity to promote better / optimum colony health by continuing this common practice?
· How biologically significant is it that we are not providing supplemental phospholipids?
Pollen Grain Fatty Acids
In our review of the botany literature regarding the fatty acid composition of floral pollen, seventy-three (73) fatty acids were identified. 5 fatty acids, namely, alpha-linolenic (Omega-3), Linoleic, Palmitic, Oleic, and Stearic respectively, were common to all samples.
Pollen grain typical fatty acid distribution
Pollen grain phospholipids
Pollen grains contain 1.5 -3 % phospholipids.
phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidyl ethanolamine (PE), phosphatidylcholine (PC), and lysophosphatidylcholine (LPC).
Phospholipid bilayers are understood to be critical components of cell membranes, and this pollen fraction is not currently being addressed in artificial feed formulations. With a phospholipid content of 60-70%, lecithin would be a viable option both commercially, and compositionally if supplemental phospholipids were to be pursued by beekeepers and manufacturers.
Details and balance
In line with our overarching methodological approach to honeybee nutrition, once our identification work was ‘complete’, we then cross-referenced the open-access entomology literature to determine what, if any, research had been conducted on this subject matter pertaining to honey bee nutrition. While not an exhaustive list, the references section of this writing provides an overview of the available literature on this topic.
This research thread indeed seems to be pointing to the biological significance of aligning the compositional fatty acid and phospholipid profiles of pollen supplements with that of floral pollen. The proportional distribution of alpha-linolenic, Linoleic, Palmitic, Oleic, and Stearic acids is certainly not difficult to mimic (spreadsheet & calculator required) with commercially available plant oils.
Oxidative degradation of polyunsaturated fatty acids (PUFA’s)
What is Lipid oxidation?
Lipid peroxidation is an oxidative chain reaction in which one lipid molecule after another becomes oxidized to the maximum possible extent or to form a lipid peroxide (i.e., a lipid molecule containing one or more O–O bonds). At high temperatures, lipid peroxides decompose to produce a range of unpleasant-tasting and foul-smelling products such as epoxides, ketones, acids, and aldehydes. Most biological membranes are extended bilayers of amphiphilic lipids with hydrophobic moieties directed to the center and hydrophilic head groups at the two surfaces. Biological cell membranes are packed with polyunsaturated fatty acids (PUFAs), such as arachidonic and docosahexaenoic acid, in either the isolated form or the incorporated form in triacyl glycerides and phospholipids. PUFAs are particularly susceptible to peroxidation.
Source: Zhengwei Cai, in Encyclopedia of Toxicology (Second Edition), 2005
To incorporate commercially available/viable sources of alpha-linolenic acid as the dominant polyunsaturated fatty acid (PUFA) in pollen supplement manufacturing practices – the issue of oxidative degradation would need to be addressed.
Note: The issue of oxidative degradation should ideally be addressed for the use of any/all polyunsaturated fatty acids (omega 3 or 6 dominant sources) in pollen supplements as the unsaturated structure of these lipid compounds makes them susceptible to oxidative degradation which results in a loss of bioactivity and the development of volatile degradation compounds. Antioxidants can limit the oxidative degradation of unsaturated compounds when included in feed formulations.
Fortunately, food science and manufacturing companies from other sectors have investigated solutions to this challenge, and economically viable options have been developed.
In biological systems, there is a balance and interplay between reductive and oxidative status behind many biological processes, and this biochemistry is fairly well-understood mechanistically.
Where there is a challenge of oxidation, antioxidants (electron donors) are most often the solution…
Supplemental reading and references:
· Omega-6:3 Ratio More Than Absolute Lipid Level in Diet Affects Associative Learning in Honey Bees https://pubmed.ncbi.nlm.nih.gov/29971031/
· Unbalanced fatty acid diets impair discrimination ability of honey bee workers to damaged and healthy brood odors https://pubmed.ncbi.nlm.nih.gov/35332922/
· NUTRITIONAL EFFECT OF ALPHA-LINOLENIC ACID ON HONEY BEE COLONY DEVELOPMENT (APIS MELLIFERA L.) https://sciendo.com/article/10.1515/jas-2015-0023
· Effect of alpha-linolenic acid on some productive and reproductive traits of the Iranian bee (Apis mellifara meda) https://discovery.researcher.life/article/effect-of-alpha-linolenic-acid-on-some-productive-and-reproductive-traits-of-the-iranian-bee-apis-mellifara-meda/296c3416db213f80ad8cc581c9cd9e9e
· Fatty acid homeostasis in honey bees (Apis mellifera) fed commercial diet supplements https://link.springer.com/article/10.1007/s13592-021-00896-0
· Omega-3 deficiency impairs honey bee learning https://www.pnas.org/doi/10.1073/pnas.1517375112
· Effect of diet lipids and omega-6:3 ratio on honey bee brood development, adult survival and body composition https://www.sciencedirect.com/science/article/abs/pii/S0022191020300172
· Antimicrobial activity of fatty acids against Bacillus larvae, the causative agent of American foulbrood disease https://www.apidologie.org/articles/apido/abs/1993/02/Apidologie_0044-8435_1993_24_2_ART0002/Apidologie_0044-8435_1993_24_2_ART0002.html
· Amino acid and lipid spectra of larvae of honey bee (Apis cerana Fabr) feeding on mustard pollen https://hal.science/hal-00891320/document
· Membrane phospholipids present in honey bee brain and association with self-grooming behavior following exposure to sublethal doses of clothianidin. https://www.researchgate.net/figure/Membrane-phospholipids-present-in-honey-bee-brain-and-association-with-self-grooming_fig4_353893449
· The membrane phospholipid composition of honeybee (Apis mellifera) workers reflects their nutrition, fertility, and vitellogenin stores https://link.springer.com/article/10.1007/s00040-018-0623-x
· Amino acid and lipid spectra of larvae of honey bee (Apis cerana Fabr) feeding on mustard pollen https://www.apidologie.org/articles/apido/abs/1996/01/Apidologie_0044-8435_1996_27_1_ART0003/Apidologie_0044-8435_1996_27_1_ART0003.html
· Mobilization of Lipids Underpins Honey Bee and Colony Health During Limited Supplementary Feeding https://assets.researchsquare.com/files/rs-1248474/v1/297ba02c-2d45-4024-9443-036024f49868.pdf?c=1690295253
· FATTY ACID COMPOSITION OF PHOSPHOLIPIDS AND SORPTION CAPACITY OF HEAD TISSUES AND PRODUCTIVE SIGNS OF BEES FED WITH FLAXSEED OIL http://baltijapublishing.lv/omp/index.php/bp/catalog/download/117/3122/6652-1?inline=1
· Honey bee caste lipidomics in relation to life-history stage and the long life of the queen https://journals.biologists.com/jeb/article/222/24/jeb207043/223520/Honey-bee-caste-lipidomics-in-relation-to-life
· Added vegetable and fish oils to low-fat pollen diets: effect on honey bee (Apis mellifera L.) consumption https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-6055.2010.00752.x
· EFFECT OF ADDING SOME VEGETABLE OILS TO POLLEN SUBSTITUTES ON PALATABILITY AND PREFERENCE OF HONEY BEE, APIS MELLIFERA L. COLONIES. https://jppp.journals.ekb.eg/article_87920_8b683297b8db8e70c5723733898ae241.pdf