Keywords: Yeast β-glucans, Animal immunity, β-glucans feeds, antibiotic alternatives, Ruminants
The livestock industry or local dairy farmers are looking for alternatives to the use of antibiotics. They are searching for supplements to enhance growth, performance, and animal health. Generally, livestock producers use antibiotics to minimize the impact of these diseases on animals. However, antibiotic use is a severe public concern as their residual presence in meat and other dairy products. Furthermore, antibiotic resistance is continuously developing in pathogenic bacteria.
Additionally, antibiotics cause environmental pollution, which is harmful to both animals and humans. However, the use of antibiotics for growth promotion is now becoming limited in various countries. Finally, the demand for alternative means of antibiotics is increasing. Multiple compounds are studied and reported to positively affect the immune system and helps in improving animal health. One of these is β-glucans which is used as supplements or animal feed additive and derived from baker yeast strain Saccharomyces cerevisiae.
β-glucans derived from different sources have different structure and function
Beta-glucans are naturally occurring sugar polysaccharides with various molecular structures. β-glucans are present in the cell wall of yeast, fungi, algae, and plants. The function of β-glucans depends upon the sources they derived and the chemical structure of the compound. The β-glucans obtained from various resources possess different chemical structures. Hence, β-glucans obtained from yeast (Saccharomyces cerevisiae) and fungi have β-(1,3) (1,6)- β-glucans and have potentially beneficial effects as supplements (Zhu et al., 2016). While, the β-glucans obtained from plants have different chemical structures β-(1,3) (1,4)- β-glucans and don’t have any potential beneficial effect on animal health and growth (Jacob & Pescatore, 2014).
Benefits of yeast β-glucans for animal health?
Among these, β-glucans obtained from yeast (Saccharomyces cerevisiae) are most effective for animal health and growth. The health benefits of β-glucans derived from Saccharomyces cerevisiae for animal development are well studied and proven. Furthermore, increasing evidence suggests these β-glucans obtained from yeast are equally beneficial for ruminants’ health and growth. The use of β-glucans in animal feed enhances meat production and its flavor. Furthermore, it improves its growth, performance, carcass performance, the composition of growing lambs, and digestibility in animals, resulting in tremendous health benefit effects and enhancing meat productions. The use of β-glucans influence the carcass composition and results in animal’s weight gain (Raa, 2015)
Control animal heat stress
Heat stress significantly affects animal growth, milk quality and production, reproduction, and disease prevalence. The farmer uses different ways like cooling, proper diet planning, and optimum feed management practices to alleviate heat stress. The increasing body of evidence shows that the use of β-glucans in animal feed helps alleviate heat stress in dairy animals (Xiangqian, 2019).
Enhance milk production and milk quality
The use of yeast β-glucans in the feed of dairy animal increase the milk production and quality. The use of yeast (Saccharomyces cerevisiae) β-glucans improves the dry matter intake in animals and enhances cow’s milk production (Wohlt et al., 1998). Similarly, yeast β-glucans also enhances dry matter intake in beef cattle, enhancing the performance of these animals (Finck et al., 2014). The yeast cell wall (β–glucans) increases milk fat up to 30% and milk protein up to 11% contents. Furthermore, it also reduces the total number of bacteria and somatic cells in milk, enhancing the milk quality. Additionally, the use of yeast β-glucans increases lactation in dairy animals up to 14%. Milk quality and production are primary parameters for monitoring farm animals (Ząbek et al., 2013; Zaleska et al., 2015).
Effect on performance and metabolism
The use of yeast β-glucans or yeast-based products modulate the immune system and play a vital role in improving the performance and metabolism of animals. The use of yeast β-glucans in dairy cows produces less volatile fatty acid concentration. Additionally, it also decreased the period of acidosis (Anjum et al., 2018; Thrune et al., 2009). Furthermore, it also affects the pH of ruminants and improves nutrition digestion. The use of yeast β-glucans has beneficial effects for weaning calves’ gastrointestinal tracts. As the gastrointestinal tract of weaning calves is underdeveloped, which results in incomplete digestion of nutrients. The use of yeast β-glucans supplements in the feed optimized the microflora in the gastrointestinal tract of weaning calves. The β-glucans reduce the pathogenic E. coli and increase the commensal bacteria Lactobacillus (J. Ma et al., 2020; Yi et al., 2009)
Yeast β-glucans boost animal immunity
The use of yeast β-glucans boosts the immune system of weaning calves. Immune systems are critical to fighting against diseases as weaning calves are more susceptible. The use of yeast β-glucans helps to induce innate and adaptive immunity. Moreover, they also play a role in activating macrophages, an integral part of the innate immune system. It also activates the macrophages in ruminants and other animals (Wojcik, 2014). The study on Holstein’s calves shows that the use of yeast β-glucans as supplements enhances the adaptive immune system (Ma et al., 2015). The adaptive immune system is just like a trained immunity. In the case of any disease infection or pathogen attack, it activates the immune responses against this disease or pathogen. The yeast β-glucans have some similarities to the compounds or molecules found in pathogens. Thus, giving yeast β-glucans supplements to young calves or animals develops an adaptive or trained immunity (Khalkhane et al., 2013).
Control of mastitis
Mastitis is a famous disease in the udder of milking cows. Mastitis is an infectious disease in dairy cows caused by inflammation of the mammary gland, which results in pain, redness, and swellings. The use of yeast β-glucans decreased the white blood cells, showing the better health and functioning of mammary glands. Furthermore, it induces the secretion and movement of leukocytes and macrophages to the site of inflammation (Waller & Colditz, 1999; Ząbek et al., 2013)
The use of yeast β-glucans not only has an immune-modulatory effect on animals and acts as biological response modifiers. Furthermore, it also enhances growth and production by improving gut health by modifying the gut microbiota composition. Yeast β-glucans based dietary supplementation in animals’ feed improves performance concerning feed intake, efficient digestion of food, and increases milk production and quality. It enhances the growth and performance of animals without any negative effects. Additionally, it helps manage infectious diseases of animals and activates the innate immune responses or develops adaptive immunity. Overall, the use of yeast β-glucans partially replaces the use of antibiotics and treatments. In conclusion, using these supplements enhances animal health and results in an overall increase in profitability.
Anjum, M. I., Javaid, S., Ansar, M. S., & Ghaffar, A. (2018). Effects of yeast (Saccharomyces cerevisiae) supplementation on intake, digestibility, rumen fermentation and milk yield in Nili-Ravi buffaloes. Iranian Journal of Veterinary Research, 19(2), 96–100.
Finck, D. N., Ribeiro, F. R. B., Burdick, N. C., Parr, S. L., Carroll, J. A., Young, T. R., Bernhard, B. C., Corley, J. R., Estefan, A. G., Rathmann, R. J., & Johnson, B. J. (2014). Yeast supplementation alters the performance and health status of receiving cattle. The Professional Animal Scientist, 30(3), 333–341.
Jacob, J. P., & Pescatore, A. J. (2014). Barley β-glucan in poultry diets. Annals of Translational Medicine, 2(2). https://doi.org/10.3978/j.issn.2305-5839.2014.01.02
Khalkhane, A. S., Abbasi, K., Zadeh, F. S., & Arian, A. H. (2013). Effect of dietary beta-glucan supplementation on humoral and cellular immunologic factors in lambs. Global Veterinaria, 11(1), 38–43.
Ma, J., Shah, A. M., Shao, Y., Wang, Z., Zou, H., & Kang, K. (2020). Dietary supplementation of yeast cell wall improves the gastrointestinal development of weaned calves. Animal Nutrition, 6(4), 507–512.
Ma, T., Tu, Y., Zhang, N., Guo, J., Deng, K., Zhou, Y., Yun, Q., & Diao, Q. (2015). Effects of dietary yeast β-glucan on nutrient digestibility and serum profiles in pre-ruminant Holstein calves. Journal of Integrative Agriculture, 14(4), 749–757.
Raa, J. (2015). Immune modulation by non-digestible and non-absorbable beta-1,3/1,6-glucan. Microbial Ecology in Health and Disease, 26.
Thrune, M., Bach, A., Ruiz-Moreno, M., Stern, M. D., & Linn, J. G. (2009). Effects of Saccharomyces cerevisiae on ruminal pH and microbial fermentation in dairy cows. Yeast supplementation on rumen fermentation. Livestock Science, 124(1–3), 261–265.
Waller, K. P., & Colditz, I. G. (1999). Effect of intramammary infusion of beta-1, 3-glucan or interleukin-2 on leukocyte subpopulations in mammary glands of sheep. American Journal of Veterinary Research, 60(6), 703–707.
Wohlt, J. E., Corcione, T. T., & Zajac, P. K. (1998). Effect of yeast on feed intake and performance of cows fed diets based on corn silage during early lactation. Journal of Dairy Science, 81(5), 1345–1352.
Wojcik, R. (2014). The effect of Leiber Beta-S (1,3-1,6-beta-D-glucan) on the phagocytic activity and oxidative metabolism of peripheral blood granulocytes and monocytes in calves. 83, 347–354.
Xiangqian, X. (2019). How to select yeast products under heat stress in dairy cows.
Yi, Z., Qiyu, D., Yan, T., & QiAng, Y. (2009). Effects of yeast β-glucan on gastrointestinal development in early-weaning calves. Chinese Journal of Animal Nutrition, 21(6), 846–852.
Ząbek, K., Milewski, S., Wójcik, R., & Siwicki, A. K. (2013). Effect of β-1,3/1,6-D-glucan in diet on productivity and humoral and cellular defense mechanisms in sheep. Acta Veterinaria Brno, 82(2).
Zaleska, B., Milewski, S., & Ząbek, K. (2015). Impact of Saccharomyces cerevisiae supplementation on reproductive performance, milk yield in ewes and offspring growth. Archives Animal Breeding, 58(1), 79–83.
Zhu, F., Du, B., & Xu, B. (2016). A critical review on production and industrial applications of beta-glucans. Food Hydrocolloids, 52, 275–288.