Feeding Saccharomyces cerevisiae; the current study situation

Introduction

This page details a recent publication written by Dr Christina Fritz of SanoAnimal.

Dr Fritz is a german biologist with a PhD in Animal Physiology/Neurobiology, and has been treating horses since 2006 focusing on metabolic therapy using holistic feeding methods.

Disclaimer: Dr Fritz's article below is entirely written by her, with permissions for us to reproduce it here.

I have not contributed in any way, nor have I expressed any opinions, to this page. EquiNatural Ltd will not accept any liability for the content of this page; we are simply sharing the content for information to those who may be interested, and the sources listed at the bottom of Dr Fritz's article can all be readily found on the world wide web. (Source data indicated throughout by the numbers in blocks [].

Please note that this page is not intended to replace veterinary or professional advice, and I would encourage anyone reading it to form their own opinions and make their own equine healthcare decisions based upon their own research.

Carol Moreton, EquiNatural Ltd

NB - Please note that the following is a literal german:english translation via Google Translate.

Feeding Saccharomyces cerevisiae - what is the current study situation?

It has long since arrived in the horse world: the intestine is the mirror of health. More and more horses are affected by so-called lifestyle diseases and suffer from colic, laminitis, EMS, insulin resistance etc. Fortunately, there are more and more publications that deal with the topic of intestinal health and the horse's microbiome.

Feeding has a significant impact on the horse's microbiome

The horse's microbiome is highly complex and reacts to a wide variety of influences, from the fiber composition of the feed to social interactions within the group [27] [28]. It has long been known that starch-rich feeding shifts the intestinal bacteria in the direction of starch-utilizing, lactic acid-producing bacteria [1] [2] [3] [4] and displaces the fiber-digesting bacteria [2] [3] [4] [5] [6], which the horse urgently needs to generate energy from hay. In the colon of horses that have never received Saccharomyces cerevisiae, Saccharomyces cerevisiae cannot be detected either - which implies that this is also not necessary for digestion in a healthy horse's intestine [7].

Saccharomyces cerevisiae survives gastric passage in horses

Probiotic feed, which includes Saccharomyces cerevisiae, must be able to arrive healthy in the large intestine and to settle there, which has a lasting effect beyond the dose [7]. As early as 2002, Medina et al. and later Jouany et al. that Saccharomyces cerevisae is able to arrive alive in the caecum and colon, i.e. the large intestine of the horse [13] [14] [15]. Contrary to popular belief, Saccharomyces cerevisisae is not completely killed in the horse's stomach.

According to the Animal Feed Act, live yeasts may be used as feed for horses

Two different Saccharomyces cerevisiae products are usually used for supplementation in horses: one is live yeast and one is a fermentation product. Both contain live yeast cultures, whereby the fermentation product contains significantly fewer live yeast cells (on average 4.67 x 103 colony forming units) than live yeast (on average 1.21 x 109 colony forming units) [10]. It is particularly worrying that there are no studies on the recommended feeding amounts for live yeast in horses [10].

Saccharomyces cerevisiae is a fattening accelerator in livestock feeding

The study situation on Saccharomyces cerevisiae is overall very inconsistent. There are significantly more studies on the application in farm animals than in horses. In farm animals, Saccharomyces cerevisiae is used in particular to accelerate weight gain in fattening [23]. This effect is particularly clear in comparison with control groups when the animals are kept under stress and severe disease pressure [30]. The mechanism why saccharomyces cerevisiae leads to a more significant weight gain in stressed animals than in non-stressed animals is not yet known. In pigs it has been shown that feeding Saccharomyces cerevisiae leads to faster weight gain, but at the same time significantly decreases the diversity of the microbiome in the intestine [29]. Even in rabbits, whose digestive system is most similar to that of the horse of all farm animals, the addition of Saccharomyces cerevisiae with otherwise the same feeding results in a significantly higher weight gain and an increase in blood parameters that indicate chronic inflammation [24]. In our horse stables, obesity has become a widespread problem that certainly has many causes. Against this background, however, it is questionable to what extent it makes sense to feed horses that speed up fattening.

Feeding starch has a greater effect on fiber digestibility than saccharomyces cerevisiae

While some publications report an improvement in the digestibility of fibers in horses, other studies show the opposite picture. Most studies that postulate increased fiber digestibility also increase starch feeding to an extent that is not used in normal horse feeding [7]. However, the changes observed in the horses fed with high levels of carbohydrates and fed with Saccharomyces cerevisiae did not differ from the control group without Saccharomyces cerevisiae and starch feeding, so that the observed changes merely returned to normal values [16]. In rabbits, too, the combination of high-starch feed with Saccharomyces cerevisiae leads to significant changes compared to the control group [24], while with a purely fiber-based feeding no significant improvements in digestibility could be demonstrated by feeding Saccharomyces cerevisiae [25]. Studies have shown that the use of probiotics in foals led to more frequent veterinary visits, as the intestinal flora of the foals was probably overgrown by the probiotics [7].

The horse's microbiome is still a big mystery

In order to be able to assess the actual effects of Saccharomyces cerevisiae on the horse's microbiome, the entire microbiome including fungi, protozoa and viruses would first have to be examined [11], not just the most common bacterial strains. In addition, most of the horses that are used in studies of the microbiome are owned by the research facility and may already have several (feeding) studies of various kinds behind them. Here, however, the research is still at the very beginning [26], so that it is impossible to foresee at all what long-term consequences an influencing of the microbiome through the feeding of Saccharomyces cerevisiae will have in horses.

Saccharomyces cerevisiae converts sugar into alcohol

Yeast has the ability to convert glucose into alcohol and CO2. The more sugar there is, the more alcohol and CO2 is produced. For this activity, it primarily needs zinc as a substrate [22], which is then removed from the food pulp.

The so-called auto-brewery syndrome has been known in humans for a long time. It can be triggered by various yeasts of the Candida and Saccharomyces family and causes the metabolism of carbohydrates to alcohol in the affected patients through their colonization in the digestive tract. These patients have increased blood alcohol levels through carbohydrate intake alone, without having directly consumed alcohol. If these patients also have diabetes mellitus, obesity or liver disease, the blood alcohol levels rise even more [17] [21]. Stress and long breaks between meals can also lead to a significant increase in blood alcohol levels in affected people [33]. Possible causes that can contribute to the development of this syndrome include frequent or long-term administration of antibiotics, a diet rich in carbohydrates, diabetes mellitus and a possibly genetic reduction in liver enzyme activity [18], [19], [20]. Chronic intestinal mucosal inflammation, such as those associated with Crohn's disease, can be related to Autobrewery Syndrome [31], but it also occurs in patients without accompanying or previous illnesses [32]. Autobrewery Syndrome leads to a deficiency of B vitamins, zinc and magnesium in humans [34]. While Saccharomyces cerevisiae is advertised as a source of B vitamins, when it settles in the gut it can do just the opposite. To date, there have been no studies of the Autobrewery Syndrome in horses or other animal species. In human medicine it is assumed that significantly more people suffer from autobrewry syndrome than are diagnosed, since these diseases are often not known to general practitioners [33].

The administration of probiotics is extremely controversial in human medica

The administration of probiotics to support the intestinal flora after administration of antibiotics is also controversial in human medicine. In a study it was even shown that the administration of probiotics delayed rather than helped the restoration of a healthy intestinal flora. In patients with acute pancreatitis, the mortality rate increased from 6% to 16% with probiotics. Prophylactic use is also rejected due to the insufficient number of studies [12].

As in human medicine, there are few approaches with a direct therapeutic indication that consider the use of probiotics in horses to be sensible. Even studies on acute enterocolitis or Salmonella excretion in horses come to different results [7], so that there is no clear result here either.

From a scientific point of view, the use of probiotics such as Saccharomyces cerevisiae in horses should be questioned critically

Overall, the results show that the use of probiotics such as Saccharomyces cerevisiae in horses requires further research and that purely preventive administration without therapeutic indication or even without consulting a competent therapist is not recommended. In the studies published so far, no long-term experiments with Saccharomyces cerevisiae feeding were undertaken or epigenetic changes were determined, so that no data at all are available on the effects of long-term administration over months or years. Many additional feeds for horses contain Saccharomyces cerevisiae without the horse owner knowing about it and it is not uncommon for several of these feeds to be given at the same time.

Most of the studies on the feeding of Saccharomyces cerevisae in horses are only about improved fiber digestibility with simultaneous administration of large amounts of starch, but not about improved health or performance of the horse, which would be the far more worthwhile reason for the horse owner to feed Saccharomyces cerevisiae.

Increased fiber digestibility when feeding large amounts of concentrated feed may be an advantage for livestock when it comes to increased yield. Most of our (leisure) horses, however, tend to struggle with obesity and the diseases that result from it, so that this argument is probably invalid in the horse sector. In addition, the fact that Saccharomyces cerevisiae is used as a fattening agent in livestock feed speaks against the administration, if you consider how many horses suffer from obesity even with just hay feeding. The risk that the fed Saccharomyces cerevisiae can settle in the horse's intestine and then lead to a picture comparable to that of the Autobrewery Syndrome in humans, with the associated deficiency symptoms of zinc and B vitamins, should stimulate critical thought.

Because the majority of our (leisure) horses show zinc deficiencies in their blood count, despite being given plenty of commercial mineral feed.

Finally, it should be mentioned that numerous publications have already reported contamination of Saccharomyces cerevisiae with antibiotics, as a result of the manufacturing process, and mycotoxins [8] [9]. These, too, have far-reaching, negative effects on the microbiome of the horse's intestine.

Sources:

[1] Destrez A, Grimm P, Cézilly F, Julliand V. Changes of the hindgut microbiota due to high-starch diet can be associated with behavioral stress response in horses. Physiol Behav 2015; 149: 159–164.

[2] Fombelle A de, Julliand V, Drogoul C, Jacotot E. Feeding and microbial disorders in horses: 1-effects of an abrupt incorporation of two levels of barley in a hay diet on microbial profile and activities. J Equine Vet Sci 2001; 21 (9): 439–445.

[3] Grimm P, Philippeau C, Julliand V. Faecal parameters as biomarkers of the equine hindgut microbial ecosystem under dietary change. Animal 2017; 11 (7): 1136–1145.

[4] Julliand V, Fombelle A de, Drogoul C, Jacotot E. Feeding and microbial disorders in horses: Part 3 – Effects of three hay:grain ratios on microbial profile and activities. J Equine Vet Sci 2001; 21 (11): 543–546.

[5] Julliand V, Grimm P. The impact of diet on the hindgut microbiome. J Equine Vet Sci 2017; 52: 23–28.

[6] Kristoffersen C, Jensen RB, Avershina E, Austbø D, Tauson A-H, Rudi K. Diet-dependent modular dynamic interactions of the equine cecal microbiota. Microbes Environ 2016; 31 (4): 378–386.

[7] Langner K, Vervuert I. Impact of nutrition and probiotics on the equine microbiota: current scientific knowledge and legal regulations. Tierarztl Prax Ausg G Grosstiere Nutztiere. 2019 Feb;47(1):35-48

[8] Gottschalk C, Biermaier B, Gross M, Schwaiger K, Gareis M. Ochratoxin A in saccharomyces cerevisiae used as food supplement. Mycotoxin Res. 2016 Feb;32(1):1-5.

[9] Hoff RB, Molognoni L, Deolindo CTP, de Oliveira T, Mattos JLS, Oliveira LVA, Daguer H. J. Residues of antibiotics in yeasts from ethanol production: a possible contamination route for feedingstuffs. Environ Sci Health B. 2021 Feb 9:1-6.

[10] Garcia-Mazcorro JF, Rodriguez-Herrera MV, Marroquin-Cardona AG, Kawas JR. The health enhancer yeast Saccharomyces cerevisiae in two types of commercial products for animal nutrition. Lett Appl Microbiol. 2019 May;68(5):472-478.

[11] Garber A, Hastie P, Murray JA. Factors Influencing Equine Gut Microbiota: Current Knowledge. J Equine Vet Sci. 2020 May; 88:102943

[12] Gießelmann, Kathrin. Dtsch Arztebl 2019; 116(33-34)

[13] Medina, B., Girard,I.D.,Jacotot,E.,Julliand,V.,2002.Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet.J.Anim.Sci.80, 2600–2609.

[14] Jouany,J.P.,Gobert,J.,Medina,B.,Bertin,G.,Julliand,V.,2008.Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-fiber or high-starch diet.J.Anim.Sci.86,39–347.

[15] Jouany,J.P.,Medina,B.,Bertin,G.,Julliand,V.,2009.Effect of live yeast culture supplementation on hindgut microbial communities and their poly-saccharidase and glycoside hydrolase activities in horses fed a high-fiber or high-starch diet.J.Anim.Sci.87,2844–2852.

[16] Taran FMP, Gobesso AAO, Gonzaga IVF, Françoso R, Centini TN, Moreira CG, Silva LFP. Effects of different amounts of Saccharomyces cerevisiae supplementation on apparent digestibility and faecal parameters in horses fed high-roughage and high-concentrate diets. Livestock Science 2016; 186: 29–33.

[17] Painter K, Cordell BJ, Sticco KL. Auto-brewery Syndrome. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2020.

[18] Logan BK, Jones AW (July 2000). Endogenous ethanol 'auto-brewery syndrome' as a drunk-driving defence challenge. Medicine, Science, and the Law. 40 (3): 206–15.

[19] Cordell BJ, Kanodia A, Miller GK (January 2019). Case-Control Research Study of Auto-Brewery Syndrome. Global Advances in Health and Medicine. 8: 2164956119837566.

[20] Saverimuttu J, Malik F, Arulthasan M, Wickremesinghe P (October 2019). "A Case of Auto-brewery Syndrome Treated with Micafungin". Cureus. 11 (10): e5904

[21] Hafez EM, Hamad MA, Fouad M, Abdel-Lateff A (May 2017). "Auto-brewery syndrome: Ethanol pseudo-toxicity in diabetic and hepatic patients". Human & Experimental Toxicology. 36 (5): 445–450.

[22] Hammes-Schiffer S, Benkovic SJ (2006). Relating protein motion to catalysis. Annual Review of Biochemistry. 75: 519–41.

[23] Okoro VM, Mbajiorgu EF, Mbajiorgu CA (2019). Yeast (Saccharomyces cerevisiae) and its effect on production indices of livestock and poultry – review. Comparative Clinical Pathology. 28: 669-677.

[24] Ezema C, Eze DC (2012). Determination oft he effect of probiotic (Saccharomyces cerevisiae) on growth performance and hematological parameters of rabbits. Comparative Clinical Pathology. 21:73-76.

[25] Chaudhary LC, Singh R, Kamra DN, Pathak NN (1995). Effect of oral administration of yeast (Saccharomyces cerevisiae) on digestibility and growth performance of rabbits fed diets of different fibre content. World rabbit science 3(1): 15-18.

[26] Julliand V, Grimm P (2016). Horse Species Symposium: The microbiome oft he horse hindgut: History and current knowledge. Journal of Animal Science. 94(6): 2262-2274.

[27] Gomez A, Sharma AK, Grev A, Sheaffer C, Martinson K. (2021). The Horse Gut Microbiome Responds in a Highly Individualized Manner to Forage Lignification. Journal of Equine Veterinary Science. 96: 103306.

[28] Stothart MR, Greuel R, Gacriliuc S, Henry A., Wilson AJ, McLoughlin PD, Poissant J (2020). Bacterial dispersal and drift drive microbiome diversity patterns within a population of feral hindgut fermenters. Molecula Ecology. 30(2): 555-571.

[29] Kiros TG, Luise D, Derakhshani H, Petri R, Trevisi P, D’Inca R, Auclair E, van Kessel AG (2019). Effect of live yeast Saccharomyces cerevisae supplementation on the performance and cecum microbial profile of suckling piglets. PLoS ONE. 14(7): e0219557.

[30] Alugongo GM, Xiao J, Wu Z. et al. (2017) Review: Utilization of yeast of Saccharomyces cerevisiae origin in artificially raised calves. J Animal Sci Biotechnol 8(34).

[31] Welch BT, Coelho Prabhu N, Walkoff L, Trenkner SW (2016). Auto-brewery Syndrome in the Setting of Long-standing Crohn's Disease: A Case Report and Review of the Literature. J Crohns Colitis. 10(12):1448-1450.

[32] Cordell BJ, Kanodia A, Miller GK (2019). Case-Control Research Study of Auto-Brewery Syndrome. Glob Adv Health Med. 8:2164956119837566.

[33] Malik F, Wickremesinghe P, Saverimuttu J (2019). Case report and literature review of auto-brewery syndrome: probably an underdiagnosed medical condition. BMJ Open Gastroenterol. 6(1):e000325.

[34] Eaton KK, McLaren JH, Hunnisett A, Harris M (1993). Abnormal gut fermentation: Laboratory studies reveal deficiency of B vitamins, zinc, and magnesium. The Journal of Nutritional Biochemistry. 4(11): 635-638.New paragraph