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What Does it Mean to Feed Algae to Horses? The story I did not want to tell.

Updated: Dec 6, 2023

I wanted this to be a happy story; a simple comparison of options, a confident purchase, and a problem solved. Unfortunately, that's not what happened. It ended up being the same old frustrating story; a spiral into an unknown kingdom, unanswered emails, shocking calculations, unfulfilled promises, and an unopened product returned. You might think that I'm being overly dramatic, but there is a personal twist. My young horse was diagnosed with chronic inflammatory airway disease, and I've tried EVERYTHING. I started with all the management strategies, the nebulizing, the steaming, the anti-inflammatories and steroids. But I had NOT tried the supplements. Of course, doing what I do, I was cautiously optimistic. We all WANT to believe that there is a magic pill we can purchase for an affordable price and our horse's chronic problems will be solved. I can hear it in the silent pauses during my consultations with owners who are exhausted from the financial and emotional burden of sourcing their horse's lack of thrift. I hear it in my own disappointment.

An AI generated image of "Horse" + "algae".

I wanted algae to be the answer very badly. I was so confident that I purchased a supplement even before completing my research. It was such an elegant idea to feed algae to horses as an environmentally savvy, safe, convenient, and seemingly rich omega-3 source! I was convinced that it would solve all of my problems and my client's horses chronic inflammatory problems alongside our global overfishing problem. I thought that I had found the fountain of equine immune health! Algae would be easy to feed (convenient), affordable, and palatable. And then, day by day, article by article, calculation by calculation, and taste test by taste test my enthusiasm crumbled to dust.

However, I don't want to leave you in total despair! There is hope that all the promise of algae will eventually materialize in the equine nutrition realm. Several large manufacturing companies have recognized it's potential and are committing research and infrastructure dollars to its technological advancement (Byrne, 2018). The aquaculture industry is leading the charge seeing as omega-3s are vitally important to the health of farmed fish. There are a handful of well known equine supplement companies creating products that lead with algae. You'll learn more about those companies and their products in the comparisons below.



It started with a cough and a recommendation which led to this simple question. What does it mean to feed algae to horses? In order to start addressing that question, I looked at the ingredients list of dozens and dozens of horse supplements. Here is the list of algae ingredients fed to horses that I found. *A comparison chart of these products is further down this article.

  1. Algal DHA: this is an oil extracted from the fermented Schizochytrium sp. algae

  2. Spirulina: a dried blue-green algae, species is most often referred to as Arthrospira platensis or spirulina platensis

  3. Lithothamnion red algae: source of calcium and magnesium for gastric buffering and not for omega-3s

What is similar about these algae ingredients is that they come from the same Kingdom of species known as Protista. They are all aquatic, photosynthetic, and their cell walls contain cellulose (Lakna, 2019). However, they diverge quickly from there. Algae differ wildly in their appearance, environment (i.e. salt water vs fresh water), number of cells, and the types of pigments that they produce which determines their color category (i.e. red, brown, blue-green algae, ect). Honestly, there are few similarities to hang your hat on.

The major difference between these algae ingredients, for our purposes, is their omega-3 types and concentrations. For example, the algal oils can be a mix of GLA, EPA and DHA or a complete isolation of the DHA only. Companies such as DSM, ADM and Alltech can produce very high concentrations of DHA from the oil of the microalgae, Schizochytrium (Science Direct, 2023). This is a very different algae compared to spirulina (Arthrospira platensis) a type of cyanobacteria. The spirulina is mostly a source of gamma-linolenic acid, a shorter fatty acid chain compared to DHA and EPA (Collaa et. al., 2004). If you dive into the topic of GLA versus EPA/DHA, you'll get lots of stories of the horse's inability to fully convert linolenic acid to DHA, but I'm not convinced that horses must consume DHA to reap the anti-inflammatory benefits, because horses evolved to eat grass and grass does not contain DHA. Grass contains linolenic acid (mostly the gamma kind; GLA), about 15.6 g/kg (Whetsell et. al., 2002), and horses convert it to DHA themselves just like us. The pure DHA products are so much more expensive that without research proof I can't get to "benefits outweigh costs". We know that horses benefit from these plant based, linolenic rich, omega-3 sources and those options are a lot cheaper.

Images of spirulina as final product whole, under a microscope, and full bacteria organism.



The primary nutrition goal that we are trying to address is inflammation and that inflammation can be anywhere. It can be in the lungs of my young horse, it can be in the musculoskeletal system of a performance horse, it can be in the digestive system of a chronic colicer or ulcer survivor. The next theoretical step is to assume that more omega-3 fatty acids in the horse's diet will prevent more inflammation. The best source of omega-3s for horses is green grass. According to my calculations, a 1,000 lbhorse grazing on good quality pasture may consume roughly 156 grams of linolenic acid (C18:3; omega-3 fatty acid) in 10 kg of dry matter grass (about 22 lbs; Whetsell et. al., 2002). Sadly, more and more equines have less and less access to daily green grass, so it becomes paramount to replace the omega-3s in the supplemental diet. If you don't have a great grasp of omega-3's in horse diets, you might first read my article "The Perfect Oil for Horses; Fat Chance" and then come back to this article. The idea of feeding algae to horses as a replacement source of essential omega-3 fatty acids isn't new, but it hasn't blossomed into a full-scale fad either. What is limiting its popularity? Is it cost? Taste? Regulation? Availability? That's what I set out to learn.

Here's why I got excited about algae as an omega-3 option. First, almost all of my clients are addressing inflammation is one way or another (ulcers, colic, myopathy, laminitis, ect.) so, it's important that I understand all of their anti-inflammatory options. The second reason I got excited is because the most common and realistic supplements of omega-3s are oils, and oils are messy. If you know me at all, you know that I like my horse diets simple and easy. Many owners have a hard time with oils, especially in boarding facilities where everything has to be mixed in baggies. I assumed that algae sources of omega-3s would mostly be powders or pellets and therefore easier to feed. This assumption turned out to be true.

My third assumption, or my desperate hope, was that algae would be a highly concentrated source of omega-3. This turned out to be complicated. Are we talking about the full algae organism or its isolated fat? Are we talking about all of it's omega-3's or just DHA? It appears that researchers and manufacturers are focusing on algae's ability to provide DHA as an environmentally friendlier fish oil replacement. They can farm algae to literally be little DHA machines! For example, the EquiForce Algae-To-Omega product guarantees 17% DHA by weight from isolating the algal oil- at a 56 gram serving of the supplement, that's 9.5 grams DHA. In comparison, the Kentucky Equine Research E03 fish oil will offer 6.75 g of combined DHA/EPA in 30 mL. Apparently, spirulina often has no detectable DHA (Collaa et al., 2004) which complicates the matter more when trying to compare algae products to grass. Not one of the supplements containing spirulina would guarantee any omega-3 amount- not even SmartPak Spirulina Pellets or the human Organic Spirulina Powder supplement by NutriCost. That's not a good sign for spirulina! So, ultimately, the question these options even begin to replace the 156 g of linolenic acid (another type of omega-3) provided by 10 kg of grass? After all of this research, I'm still not sure.

With no omega-3 guarantee in any of the spirulina products, I got worried. Was feeding 30 grams of spirulina better or worse than grinding up 30 grams of green grass and feeding it to a 1,200 lb animal? According to Collaa et al. (2004), up to 20.6% of the total fatty acids in Spirulina (Spirulina platensis) is gamma-linolenic acid (C18:3). That was supported by another article (Diraman et. al., 2009), but the range is wide, from 4.07-22.51% of the total fatty acids. If 4-8% of spirulina is fat, than that's 0.48 grams of linolenic acid in 30 grams of spirulina at best (AlFadhly et. al., 2022; Wikipedia Contributors, 2023). I'm using 30 grams in this calculation, because the range of spirulina equine supplement feeding rates were between 20-40 grams per day. In comparison, my calculations suggest that green grass is equivalent at 0.47 grams linolenic acid per 30 grams. Ugh...feeding spirulina is like feeding a handful of grass to your horse. Oh my!!!

My spirulina experiment failure! No wonder it's used as a coloring agent.

Fourth assumption: I assumed that algae would be palatable. Maybe I assumed this because algae is more grass-like, but this also was not true. Turns out, this is why companies have to mix so many other ingredients with the algae is to make horses eat it. I tried to circumnavigate the equine supplement companies thinking I was being really smart and savvy to buy a cheaper source of spirulina from the human marketplace, but nope. The horses hated it and it made a huge mess. *See images above.



If you're still with me, you're probably clinging to hope that algae could be the answer to your horse's inflammation, because the idea of using fish oil is unpalatable. So let's complete our comparisons.

All of the algal DHA products were over $3 per day to feed with the cheapest one, Platinum Performance Skin & Allergy, costing $1,161 per year and only offering half of a gram of DHA. Is half a gram meaningful to a 1,000 lb animal who produces it in their own bodies? I don't think I could recommend this in good conscience! EquiForce's Algae-to-Omega claims 19 grams of DHA per recommended 2 scoop serving, nearly 20x the amount from Platinum Performance Skin & Allergy, but it cost $5.67 per day to feed. This is likely a more effective dose, but very few are willing to pay for it long term?

The Arenus Aleira, strongly recommended by my vet, was perhaps the greatest disappointment, because I was all in until.... This product guarantees 1.5 g of DHA in one 30 gram scoop in addition to 5 g MSM, mushrooms, and vitamin C, but you'll pay $3.67 per day for that gram and a half. They were professional enough to respond to my email questions (big bonus points), but the research synopsis that they sent me was a bit embarrassing! The study committed several of the Almighty research sins; they measured two factors at once (dust free pelleting and the inclusion of Aleira), they used owner provided data as a metric, and the horse's environments were not homogenized (Nogradi et. al., 2015). Seriously...??? I mean I get that horse research is expensive, but did they really need to mix TWO FACTORS at once? I tell this to anyone related to science and they laugh. These horses were switched onto a 100% pelleted diet and fed a couple ounces of Arenus Aleira. Which factor do you think had the greatest effect on these horses' health? I'm sure that most horse owners would prefer to add grams of anything instead of feeding a complete pelleted diet, but I can't recommend this product and feel good about myself.

The EquiForce Algae-To-Omega appears to be several times more DHA dense than its competition. I would love to recommend it except for two concerns; 1) cost per day and 2) marketing claims. The website references two studies on the Algae-To-Omega page. The first, by Kansas State University, sounds very interesting, but I can't find the study anywhere in a published journal. I found a reference to it in an AAEP Proceedings document titled "Review of Alternative Therapies for EIPH" by Erickson et. al. (2007), but when you find it in the references it says "unpublished data"! Then, to make things even worse, a study by Portier et. al. (2006) is referenced, but from what I read of the study they DID NOT find significant changes in fluidity of the red blood cell membranes. They state this several times in the complete article! I hope I can be proven wrong here. They did find a change in the amount of long chain fatty acids in the membrane, but this did not transfer to greater membrane fluidity after exercise or better performance.

Finally, in the comparison chart above, you'll notice 5 products with spirulina in the active ingredients list. Products guaranteed anywhere from 3 to 20 grams of spirulina per scoop, but none of them guarantee any omega-3 levels. What stood out to me immediately was how 4/5 of them also contained MSM. MSM is a very inexpensive anti-inflammatory, so if we feed these products, how do we know that it's not the cheap MSM solving our horse's problems instead of the spirulina? Maybe I just start with MSM for my horse's chronic inflammation. As stated previously, the spirulina may have equivalent omega-3 type and density to green grass, so that would mean that feeding a few grams a day is an exercise in eating money.



The story of algae is all too familiar to me. I can't tell you how many hours I've spent over the years digging into supplement comparisons just to come up empty handed; supplement companies not returning my emails, dozens of unproductive hours spent searching for documentation to support their claims, the calculations leaving me in disbelief. It's very frustrating. I do this for a LIVING, and I can't tell you if x product will solve your y problem.

You're probably wondering what I did to help my young horse. Well, I have a tub of MSM and a bottle of fish oil on the way for a total of daily cost of <$2.00. I'll wait for the algae prices to go down. Yes, I want to help the fishes from being overfished too, but I don't want to spend $3-5 per day for a tiny maybe. And that right there is the best summary of my weeks long research- a microscopic maybe.


AlFadhly, NKZ, Alhelfi N, Altemimi AB, Verma DK, Cacciola F, Narayanankutty A. Trends and Technological Advancements in the Possible Food Applications of Spirulina and Their Health Benefits: A Review. Molecules. 2022 Aug 30;27(17):5584. doi: 10.3390/molecules27175584. PMID: 36080350; PMCID: PMC9458102. Retrieved on November 30, 2023 from,linoleic%20acid%2C%20and%20palmitic%20acid.

Byrne, Jane. Alltech has not exited algae. August 29, 2018. Retrieved November 29, 2023 from

Collaa, L.M., T.E. Bertolina, and J.A.V Costab. 2004. Fatty Acids Profile of Spirulina platensis Grown Under Different Temperatures and Nitrogen Concentrations. Naturforsch. 59;55-59.

Diraman, H., E. Koru, Edis, and H. Dibeklioglu. 2009. Fatty Acid Profile of Spirulina platensis Used as a Food Supplement. Israeli Journal of Aquaculture- Bamidgeh, 61(2), 134-142. Retrieved November 30, 2023 from

Erickson, H.H., T.S. Epp, and D. C. Poole. Review of Alternative Therapies for EIPH. AAEP Proceedings. 2007; 53:68-71.

Lakna. What is the Difference Between Red Brown and Green Algae

Nogradi N, Couetil LL, Messick J, Stochelski MA, Burgess JR. Omega-3 fatty acid supplementation provides an additional benefit to a low-dust diet in the management of horses with chronic lower airway inflammatory disease. J Vet Intern Med. 2015; 29(1): 299-306.

Portier, K., de Moffarts, B., Fellman, N., Kirschvink, N., Motta, C., Letellier, C., ... & Coudert, J. (2006). The effects of dietary N‐3 and antioxidant supplementation on erythrocyte membrane fatty acid composition and fluidity in exercising horses. Equine Veterinary Journal, 38(S36), 279-284.

Science Direct. Schizochytrium. Accessed November 21, 2023 from,its%20total%20fatty%20acid%20production.

Wikipedia contributors. (2023, November 11). Spirulina (dietary supplement). In Wikipedia, The Free Encyclopedia. Retrieved 16:11, November 27, 2023, from

Whetsell, M.; Rayburn, E.; Swartz, D.; Fultz, S. 2002. Variation of Fatty Acids in Cool-Season Grasses. Agronomy.12;1380. https:// Retrieved November 27, 2023 from


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