Blood serum metabolites (Means ± SEM) in dairy heifers fed on control and foreign probiotic yeast.
Abstract
The gut associated microbiota of animal plays crucial rule in the conversion to accessible nutrients for improve animal health and well-beings. Probiotic yeast (PY) is commonly use to manipulate the gut microbial balance by inhibits the disease-causing microbes and increase the number and function of desirable microbes. PY produce many fermentation metabolites, intercellular effectors, minerals and enzymes that make it an idea nutritive feed supplement for ruminants. The mode of action of the PY is depends on the animal biological inheritance, breed, managemental condition and microbial feeding type. Therefore, PY must formulate using same ecological origin, alone with desirable target; as it would be more compatible with gut ecoysytem and would yield maximum outputs as compare to non-target or foreign probiotic (FP). Therefore, for development of the Indigenous Target Probiotic (ITP), the isolation source must be same ecological region with desirable target like improve animal health and productivity. In the situation of the increase food storage around the world, ITP may provide a useful feed supplements to improve the food production in cost effective manner as compare to FP. Probiotic effectiveness is considered to be population/breed/target specific due to difference in the feed intake, change gut microflora, different food habits and different host-microbial interactions. In this chapter, we will highlight the preparation of the ITP yeast and its mode of action on animal gut microbiota.
Keywords
- indigenous target probiotic (ITP)
- Saccharomyces cerevisiae
- mode of action
- gastrointestinal tract
- fiber digestion
1. Introduction
Probiotic are the live microbial feed supplements which provide the beneficial impact on the host by producing the useful metabolites [1]. Many probiotics have been available in the market for improving animal and human health in safe and healthy way. The commercially available probiotic product contains mostly lactic acid bacteria (
In the situation of high animal feed cost, we must identify the cost-effective probiotic by using the concept of ITP to improve poor quality feed into high quality milk and meat. We had already given the concept of indigenous probiotic yeast our previous book chapter [31]. A clear understanding regarding the proposes guidelines to develop the ITP to improve gut microbiota resultantly improve milk and meat production. This book chapter will discuss the identification of the microbial strain from local ecological breed and its mode of action for preparation of target based probiotic products. We will also support our concept of ITP with our lab conducted experiments.
2. Yeast: promising microbe for development of target probiotic for animal use
Yeast is a very useful microorganism with broad range of industrial application, because of their unique genetics and physiology. Yeast cells have many useful metabolites (protein, carbohydrate, vitamins; vitamin B6, thiamin, biotin, riboflavin, nicotinic acid and pantothenic acid and minerals; zinc and magnesium) [10]. The utilization of the naturally prepared yeast would be accelerated in coming years due to the nature-oriented mind set of the consumers. Therefore, research on the isolation of the nutritious rich yeast strains for preparation of probiotic product has rapidly increased [11, 12]. Yeast is an important single cell microorganism, belongs to fungus family and it multiplies by cell division. The genetics and physiology of the yeast are very unique, and, therefore, a broad range of research work in biological sciences is being carried out on this microbe. The yeast cell size is composed of 5 × 10 μm and the size of the baker’s yeast genome is 12.1 Mb containing 16 chromosomes and 5400 coding genes approximately [13]. Members of the order Saccharomycetales are mainly used for the animal probiotics when serves as reliable and economical source of essential amino acids, vitamins, carbohydrates, and minerals from yeast cell. Thiamin, Riboflavin, Niacin and Biotin are present in yeast [14]. The antagonistic ability of the yeast to block bacterial pathogenicity is also makes its very useful [15]. Yeast cell has competition for nutrients, pH changes in the medium, high concentrations of ethanol production, secretion of antibacterial compounds and release of antimicrobial compounds are major antagonistic steps. Yeast cell has many useful fermentation metabolites (protein, vitamins, carbohydrates) which makes it important microbial feed supplement. Yeasts are naturally present (1.3 X 105 yeasts ml-1) inside the rumen fluid [16]. Literature showed that, yeasts (
3. Probiotic yeast for neonatal and growing ruminant diet
The role of the probiotic yeast in dairy animal is well studied [25]. They have been extensively used for improve milk yeast and its composition in cost effective manners. The benefits to cost ratio of probiotic yeast is 4:1 in dairy animals. They have also used as preventer against digestive problems, and rumen acidosis.
The main target of the PY used in new born ruminate diet are; (a) improvement in the rumen maturation; (b) stop the pathogenic bacterial growth; (c) establishment of the normal growing animals like microbial flora [26, 27, 28]. Microbial based feed can improve the rumen development during the growing phase of the dairy animals. The new born gut is sterile and have no germ [29]. After 6 months of age the rumen is colonized with diverse microbial flora. PY provides beneficial metabolites and enzymes like thiamine for fast growth of the fungi. The poor fungal growth of the animal fed on PY might be due to the low production of thiamine [30]. At the same time, the animal plays an important role in the maximum colonization of the beneficial microbial population [31]. If there is any imbalance bacterial species, it would result in digestive problems and leads to the economic loss. The establishment of the useful bacterial strains results in the development of strong and balanced rumen which resultantly strong immunity and health condition [32, 33]. PY provide the improve the rumen maturation and its microbial flora is also in strong balance. PY provide the useful bacterial species for feed digestion, like cellulolytic bacterial species and ciliate protozoa [34]. The balance in rumen microbial flora plays a crucial role in feed utilization and could result in better animal productivity [35]. PY remove oxygen from rumen and provides a more anaerobic environment for its growth of key beneficial microbial groups [36]. The newborn gut can easily be modulating by PY. The new born key beneficial microbial
4. Manipulation of ruminal gut microbiota by target probiotic (Fibrolytic probiotic )
For clear understanding of the ruminal gut microbiota using latest genomic methods to get useful information for preparation of specific probiotics. The ruminants feed consists of concentrate, silage, seasonal fodders etc. There diet mostly contains cellulose, hemicellulose starch and water-soluble carbohydrate. The rumen microbes play an important role in feed digestion. The animal feed is digested inside rumen and then energy is released for animal use. Cow and its microbes are mutually benefiting each other (Figure 2). Rumen is the first and the largest anaerobic chamber of the cow GIT. The temperature inside the rumen chamber is between 38 to 41 oC, with 6-7 pH (depends on feed type). There are three different types of microbes present inside the rumen including, bacteria, fungi and ciliated protozoa [41, 42, 43, 44]. The location and size of the rumen microbes depends on the feed formulation and host genetic. Mostly, bacteria are associated with fibrous feed particles; fungi, protozoa [45, 46]. Some are freely living and some are bound with rumen mucous membrane. 1 ml of the rumen is composed of 109 to 1010 per ml bacteria with 200 different species, 104 to 106 per ml protozoa with 20 different species, and 103 per ml fungi with 20 different species [47]. The rumen bacteria are gram negative 1-2 micrometer in size and cocci, and rod shaped mostly. Rumen bacterial are mostly non-spore producing, facultative anaerobes. 1- 5 % of the bacterial cells in rumen are cellulose digesters [48]. The rumen fungi (gut fungi) also play an important role in fiber digestion by stimulating growth of fibrolytic bacteria [49]. The rumen microbial features are heritable; moreover, animals age, feed and genome plays an important role in the microbial colonization. The composition of the diet describes the type of gut microbial species [50]. Therefore, the rumen microbiota can be manipulated by using the yeast-based probiotic to obtained the useful products. The feed must be targeted for modulating the rumen microbiota (Figure 3).
The modulation of the rumen microbiota is mostly for the enhanced colonization of the fiber digesting microbiota [35, 36]. Literature showed that, animal diet has an important role in the manipulation of the rumen microbiota. Low amount of fibrous feed builds up fast working microbes (fibre-degrading Butyrivibrio fibrisolvens and F. succinogenes) and high amount of fibrous build up slow working fiber degrading microbes
5. Prepration of indigenous probiotic yeast: right choice for maximum outcomes
The gut microbiota can digest the animal feed and produce nutrients for improve host health and well beings. Animal feed and host genetics play important role in shaping and composition of gut microbiota [18]. Same is the case of the rumen microbiota, which is highly variable and is depended on various factors like animal breed, physiology, feed type and geographical location. It has been commonly accepted that commercially available probiotic yeast may not showed equal impact to all animal breeds [65, 66]. The compatibility of PY could be variable among animals. The local prepared yeast probiotic isolated from same ecological niche may have more beneficial impact than any exotic probiotic yeast [3]. The local isolated probiotic yeast may have fast adaptability and colonization in the local rumen ecosystem [24]. The origin of the probiotic strain determines the best prepared probiotic product. The strain selection is the most important step for the development of right probiotic for animal. Being precise during the strain’s selection could yield positive outcomes from the probiotic. The probiotic yeast may use for the rumen microbial manipulation [67]. Different types of PY have been used for improve animal health and production [7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68]. Some PY strains produced beneficial results in animals while others did not. The difference of that variable results of PY may be explained by different host and PY associated factors [69, 70, 71]. These factors are; animal age, breed, sex, feeding dose, PY strains isolation source and some unknown factors [3]. The major factors might be the low compatibility of the exotic probiotic yeast strain with animal having diverse biological inheritance and gut microbial composition. The right probiotic strain should be novel, so we must use latest molecular methods to isolate the target specific/local isolated microbial strains. The local isolated and molecular identified probiotic strains may have more impact on local animals in cost effective manners. The probiotic are species specific by targeting the indigenous strains and local dairy farms can get the cost-effective probiotic product for improve milk production and composition.
The main steps involved in the preparation of the breed specific probiotic yeast are as following [3].
Pre-plan ruminate diet for isolation of probiotic yeast
Identification of yeast strain based on the molecular techniques
Probiotic potential of selected yeast strains
In vitro probiotic potential
Safety assessment/In-vivo animal model
6. Mode of action of the IPY Vs FPY inside the rumen and post-ruminal GIT
The first mode of action of the probiotic yeast is competitive exclusion (CE) [27]. The CE is a probiotic mode of action that involves the colonization of the beneficial microbial strains to GIT tract to reduce the addition of disease-causing microbial flora [18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74]. The ability of probiotic yeast cell to fight with other useless microbial flora can improve growth and function of beneficial microbial flora. The IPY has the indigenous strain, which has the advantage that it drives from animal of interest (Cow). IPY has an environmental modification capability. The concept of co-evolution of host microbial has been seen in case of IPY mode of action. The local strain gains an advantage because of its ability to adjust/modify itself in new environment by producing the antimicrobials e.g (lactic acid) to make its less suitable for its competitors. The FPY has the foreign origin strain, which has the less environmental modification capability less, competition for available nutrients, and mucosal adhesion sites. Second mode of action of the PY is reported as a good pH stabilization. Rumen microbial flora can work under stable pH [75]. Rumen pH is highly affected by animal feed intake and its composition. Ruminants eat different types of feed, like high energy concentrate diet, fodder, and silage. These types of feed have a quick impact on rumen pH. If rumen pH is not stable, the animals may have different types of metabolic diseases [76]. Literature showed that PY has a stabilizing effect on the rumen pH [77, 78]. Some studies reported a rise rumen pH when animal was fed on diet with high energy supplemented with PY. Sometimes, the increased pH might be due to the decreased VFAs inside the rumen [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79]. The lower pH leads to the rumen acidosis, PY can prevent the acidosis condition of the dairy animals [7]. The third proposed mechanism is that yeast cell provides the anaerobic condition inside rumen by removing the oxygen thus facilitated the useful feed digestion microbes [35, 36]. The main microbial flora are bacteria fungi and protozoa. These microbial species have a fiber digestion role by secreting the cellulase and hemicellulase enzymes. Fiber is the main part of the ruminant diet. Therefore, fiber digestion, nature blessed them with unique fibrolytic digestion bacteria (
7. Experimental proofs: who is better; indigenous or foreign microbe as animal probiotic?
7.1 Experiment: impact of probiotic yeast on blood fecal biomarkers in dairy heifers and growing animals
Based upon the above discussion, we have conducted two research experiments on dairy animals by using the IPY concept to improve the gut health. In experiment 1, eight dairy heifers (87 ± 5 kg and 6–7 months) were divided into two equal groups (control n = 4 and probiotic n = 4)[80]. Control group animals fed on NRC recommended diet and probiotic group animals fed control diet FPY (Yea-Sac1026; 5 g/animal). After 120 days results showed that the FPY significantly affected the serum glucose, and urea levels in dairy heifers [24].
That means, we had a proof of positive impact of PFY on animal health. We had isolated the yeast from dairy animals fed on yeast. After careful assessment of the probiotic potential, we conducted another experiment to determine the impact of FPY Vs IPY on the health of lactating dairy cattle. Mix breed (
We highlighted that improved animal health condition might be due to improved digestive enzymes produced from well propagated IPY. The VFAs have a capability to reduce the triglycerol and cholesterol in liver cells and might be change the animal lipid profile. Results of the ruminal gut microflora showed that the average, beneficial
It can be concluded IPY improves the, gut health, and wellbeing of lactating dairy cattle in cost effective manner. IPY strain may adopt well in the cattle gut than FPY [80].
8. Conclusion
Ruminants of developing and developed countries have different types of gut microbiota due to their living standard, feeding type, their managemental style. Although from above discussion we have a clear understanding that the interlink between gut microbiota and fiber digestion plays a key role for obtaining maximum profit from dairy animals. Therefore, the PY must be target specific which give maximum outcomes in cost effective manners. For animals of specific geographical region, a unique and precise YP must be designed by isolating the local yeast strains from that population, only then maximum beneficial outputs can be obtained. The reason beings, compactivity of the local strains with normal microbiota of the rumen ecosystem (Figure 9).
9. Recommendations
The recommendations are outlined as follows;
Pre-plane feed formulation for the manipulation of the rumen microbiota to digest the fibrous feed
Identification of breed specific probiotic strains with same target.
Whole genome sequencing of the probiotic strains as well as animal for maximum outputs
Mode of action of the probiotic should studied well for understanding of the useful and useless probiotic.
References
- 1.
Akin DE, Benner R. Degradation of polysaccharides and lignin by ruminal bacteria and fungi. 1988; Applied and Environmental Microbiology 54 1117-1125 - 2.
Akin DE. Histological and Physical Factors Affecting Digestibility of Forages. 1989; Agronomy Journal 81 17-25 - 3.
Alayande, Kazeem Adekunle, Olayinka Ayobami Aiyegoro, Thizwilondi Michael Nengwekhulu, Lebogang Katata-Seru, and Collins Njie Ateba. "Integrated genome-based probiotic relevance and safety evaluation of Lactobacillus reuteri PNW1." Plos one 15, no. 7 (2020): e0235873 - 4.
Arakaki L, Stahringer R, Garrett J, Dehority B. The effects of feeding monensin and yeast culture, alone or in combination, on the concentration and generic composition of rumen protozoa in steers fed on low-quality pasture supplemented with increasing levels of concentrate. 2000; Animal Feed Science and Technology 84 121-127 - 5.
Beev, G., P. Todorova, and S. Tchobanova. "Yeast cultures in ruminant nutrition." Bulgarian Journal of Agricultural Science 13 (2007): 357-374 - 6.
Bonhomme A. Rumen ciliates: their metabolism and relationships with bacteria and their hosts. 1990; Animal Feed Science and Technology 30 203-266 - 7.
Callaway E, Martin S. Effects of a Saccharomyces cerevisiae culture on ruminal bacteria that utilize lactate and digest cellulose. 1997; Journal of Dairy Science 80 2035-2044 - 8.
Chaucheyras-Durand F, Chevaux E, Martin C, Forano E. Use of Yeast Probiotics in Ruminants: Effects and Mechanisms of Action on Rumen pH, Fibre Degradation, and Microbiota According to the Diet. 2012; Probiotic in Animals. InTech Open Book Publisher - 9.
Chaucheyras-Durand, F., and H. Durand. "Probiotics in animal nutrition and health." Beneficial microbes 1, no. 1 (2010): 3-9 - 10.
Chaucheyras-Durand, F., N. D. Walker, and A. Bach. "Effects of active dry yeasts on the rumen microbial ecosystem: Past, present and future." Animal Feed Science and Technology 145, no. 1-4 (2008): 5-26 - 11.
Chaucheyras-Durand, F., N. D. Walker, and A. Bach. "Effects of active dry yeasts on the rumen microbial ecosystem: Past, present and future." Animal Feed Science and Technology 145, no. 1-4 (2008): 5-26 - 12.
Chaucheyras-Durand, Frédérique, Eric Chevaux, Cécile Martin, and Evelyne Forano. "Use of yeast probiotics in ruminants: Effects and mechanisms of action on rumen pH, fibre degradation, and microbiota according to the diet." Probiotic in animals (2012): 119-152 - 13.
Chenoll, Empar, Inmaculada Moreno, María Sánchez, Iolanda Garcia-Grau, Ángela Silva, Marta González-Monfort, Salvador Genovés et al. "Selection of new probiotics for endometrial health." Frontiers in cellular and infection microbiology 9 (2019): 114 - 14.
Cox, Faith, Peter H. Janssen, Gemma Henderson, Arjan Jonker, Wayne Young, and Siva Ganesh. "Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range." (2015) - 15.
Crossland, Whitney Lynn, Aaron Bradley Norris, Luis Orlindo Tedeschi, and Todd Ryan Callaway. "Effects of active dry yeast on ruminal pH characteristics and energy partitioning of finishing steers under thermoneutral or heat-stressed environment." Journal of animal science 96, no. 7 (2018): 2861-2876 - 16.
Czerucka, D., T. Piche, and P. Rampal. "yeast as probiotics–Saccharomyces boulardii." Alimentary pharmacology & therapeutics 26, no. 6 (2007): 767-778 - 17.
De Mulder, Thijs, Nico Peiren, Leen Vandaele, Tom Ruttink, Sam De Campeneere, Tom Van de Wiele, and Karen Goossens. "Impact of breed on the rumen microbial community composition and methane emission of Holstein Friesian and Belgian Blue heifers." Livestock Science 207 (2018): 38-44 - 18.
Dolezal P, Dolezal J, Szwedziak K, Dvoracek J, Zeman L, Tukiendorf M, Havlicek Z. Use of Yeast Culture in the TMR of Dairy Holstein Cows. 2012; Iranian Journal of Applied Animal Science 2 51-56 - 19.
Elghandour MM, Salem AZ, Castañeda JS, Camacho LM, Kholif AE, Chagoyán JC. Direct-fed microbes: A tool for improving the utilization of low quality roughages in ruminants. 2015; Journal of Integrative Agriculture 14 526-533 - 20.
Elghandour, M. M. Y., Tan, Z. L., Abu Hafsa, S. H., Adegbeye, M. J., Greiner, R., Ugbogu, E. A., … & Salem, A. Z. M. (2020). Saccharomyces cerevisiae as a probiotic feed additive to non and pseudo-ruminant feeding: a review. Journal of applied microbiology, 128(3), 658-674 - 21.
Elghandour, M. M. Y., Z. L. Tan, S. H. Abu Hafsa, M. J. Adegbeye, R. Greiner, E. A. Ugbogu, J. Cedillo Monroy, and A. Z. M. Salem. "Saccharomyces cerevisiae as a probiotic feed additive to non and pseudo-ruminant feeding: a review." Journal of applied microbiology 128, no. 3 (2020): 658-674 - 22.
El-Ghani AA. Influence of diet supplementation with yeast culture ( Saccharomyces cerevisiae ) on performance of Zaraibi goats. 2004; Small ruminant research 52 223-229 - 23.
Elliott, Christopher L., Joan E. Edwards, Toby J. Wilkinson, Gordon G. Allison, Kayleigh McCaffrey, Mark B. Scott, Pauline Rees-Stevens, Alison H. Kingston-Smith, and Sharon A. Huws. "Using ‘Omic approaches to compare temporal bacterial colonization of Lolium perenne, Lotus corniculatus, and Trifolium pratense in the rumen." Frontiers in microbiology 9 (2018): 2184 - 24.
Elliott, Christopher L., Joan E. Edwards, Toby J. Wilkinson, Gordon G. Allison, Kayleigh McCaffrey, Mark B. Scott, Pauline Rees-Stevens, Alison H. Kingston-Smith, and Sharon A. Huws. "Using ‘Omic approaches to compare temporal bacterial colonization of Lolium perenne, Lotus corniculatus, and Trifolium pratense in the rumen." Frontiers in microbiology 9 (2018): 2184 - 25.
Fernández-Pacheco, Pilar, Carolina Cueva, María Arévalo-Villena, M. Victoria Moreno-Arribas, and Ana Briones Pérez. "Saccharomyces cerevisiae and Hanseniaspora osmophila strains as yeast active cultures for potential probiotic applications." Food & function 10, no. 8 (2019): 4924-4931 - 26.
Ferraretto LF, Shaver RD, Bertics SJ. Effect of dietary supplementation with live-cell yeast at two dosages on lactation performance, ruminal fermentation, and total-tract nutrient digestibility in dairy cows. 2012; Journal of Dairy Science 95 4017-4028 - 27.
Fuller R. Probiotics in man and animals. 1989;The Journal of Applied Bacteriology 66 365-378 - 28.
Garcia-Mazcorro, J. F., S. L. Ishaq, M. V. Rodriguez-Herrera, C. A. Garcia-Hernandez, J. R. Kawas, and T. G. Nagaraja. Review"Are there indigenous Saccharomyces in the digestive tract of livestock animal species? Implications for health, nutrition and productivity traits." animal 14, no. 1 (2020): 22-30 - 29.
Ghazanfar S. Study on the effects of dietary supplementation of Saccharomyces cerevisiae on performance of dairy cattle and heifers. 2016; PhD Thesis. Quaid-i-Azam University, Islamabad. Pakistan - 30.
Ghazanfar S. Study on the effects of dietry supplmentation of Saccharomyvces cerevisiae on performance of dairy cattle and heifers. 2016; PhD Thesis. Quaid-i-Azam University, Islamabad. Pakistan - 31.
Ghazanfar, Shakira, Nauman Khalid, Iftikhar Ahmed, and Muhammad Imran. "Probiotic yeast: mode of action and its effects on ruminant nutrition." Yeast—Industrial Applications, IntechOpen (2017): 179-202 - 32.
Ghazanfar, Shakira, Nauman Khalid, Iftikhar Ahmed, and Muhammad Imran. "Probiotic yeast: mode of action and its effects on ruminant nutrition." Yeast—Industrial Applications, IntechOpen (2017): 179-202 - 33.
Giang, Hoang Huong, Tran Quoc Viet, Brian Ogle, and Jan Erik Lindberg. "Effects of supplementation of probiotics on the performance, nutrient digestibility and faecal microflora in growing-finishing pigs." Asian-Australasian Journal of Animal Sciences 24, no. 5 (2011): 655-661 - 34.
Gijzen HJ, Lubberding HJ, Gerhardus MJT, Vogels GD. Contribution of rumen protozoa to fibre degradation and cellulase activity in vitro. 1988; FEMS Microbiology Letters 53 35-43 - 35.
He, Z. X., B. Ferlisi, E. Eckert, H. E. Brown, A. Aguilar, and M. A. Steele. "Supplementing a yeast probiotic to pre-weaning Holstein calves: Feed intake, growth and fecal biomarkers of gut health." Animal Feed Science and Technology 226 (2017): 81-87 - 36.
Henderson, Gemma, Faith Cox, Siva Ganesh, Arjan Jonker, Wayne Young, Leticia Abecia, Erika Angarita et al. "Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range." Scientific reports 5 (2015): 14567 - 37.
Hillal, Hany, Gamal El-Sayaad, and Mohamed Abdella. "Effect of growth promoters (probiotics) supplementation on performance, rumen activity and some blood constituents in growing lambs." Archives Animal Breeding 54, no. 6 (2011): 607-617 - 38.
Hungate, R. E. "The rumen microbial ecosystem." Annual Review of Ecology and Systematics 6, no. 1 (1975): 39-66 - 39.
Jackson, Scott A., Jean L. Schoeni, Christina Vegge, Marco Pane, Buffy Stahl, Michael Bradley, Virginia S. Goldman, Pierre Burguière, John B. Atwater, and Mary Ellen Sanders. "Improving end-user trust in the quality of commercial probiotic products." Frontiers in microbiology 10 (2019): 739 - 40.
Joblin K. Physical disruption of plant fibre by rumen fungi of the Sphaeromonas group. The Roles of Protozoa and Fungi in Ruminant Digestion. 1989; Penambul Armidale NSW 259-260 - 41.
Kamra, Devki Nandan. "Rumen microbial ecosystem." Current science (2005): 124-135 - 42.
Khatri, Indu, Rajul Tomar, K. Ganesan, G. S. Prasad, and Srikrishna Subramanian. "Complete genome sequence and comparative genomics of the probiotic yeast Saccharomyces boulardii." Scientific reports 7, no. 1 (2017): 1-12 - 43.
Konsue, Wilasinee, Tida Dethoup, and Savitree Limtong. "Biological control of fruit rot and anthracnose of postharvest mango by antagonistic yeasts from economic crops leaves." Microorganisms 8, no. 3 (2020): 317 - 44.
Krause, D. O., T. G. Nagaraja, A. D. G. Wright, and T. R. Callaway. "Board-invited review: rumen microbiology: leading the way in microbial ecology." Journal of animal science 91, no. 1 (2013): 331-341 - 45.
Lesmeister, K. E., Arlyn Judson Heinrichs, and M. T. Gabler. "Effects of supplemental yeast (Saccharomyces cerevisiae) culture on rumen development, growth characteristics, and blood parameters in neonatal dairy calves." Journal of dairy science 87, no. 6 (2004): 1832-1839 - 46.
Li, Fuyong, Changxi Li, Yanhong Chen, Junhong Liu, Chunyan Zhang, Barry Irving, Carolyn Fitzsimmons, and Graham Plastow. "Host genetics influence the rumen microbiota and heritable rumen microbial features associate with feed efficiency in cattle." Microbiome 7, no. 1 (2019): 92 - 47.
MA, Song-cheng, Jing CHEN, and Hua-ming MAO. "Rumen Microbial Ecosystem [J]." China Animal Husbandry & Veterinary Medicine 1 (2007) - 48.
Martinez-Fernandez, Gonzalo, Stuart E. Denman, Chunlei Yang, Jane Cheung, Makoto Mitsumori, and Christopher S. McSweeney. "Methane inhibition alters the microbial community, hydrogen flow, and fermentation response in the rumen of cattle." Frontiers in Microbiology 7 (2016): 1122 - 49.
Mestecky J, Russell M. Passive and active protection against disorders of the gut. 1998; Veterinary Quarterly 20 83-87 - 50.
Morgavi, D. P., Evelyne Forano, Cécile Martin, and C. Jamie Newbold. "Microbial ecosystem and methanogenesis in ruminants." Animal: an international journal of animal bioscience 4, no. 7 (2010): 1024 - 51.
Morgavi, Diego, William Kelly, Peter Janssen, and Graeme Attwood. "Rumen microbial (meta) genomics and its application to ruminant production." Animal 7, no. Suppl. 1 (2013): 184-201 - 52.
Musa H, Wu S, Zhu C, Seri H, Zhu G. The potential benefits of probiotics in animal production and health. 2009; Journal of Animal and veterinary Advances 8 313-321 - 53.
Newbold C, Wallace R, Chen X, McIntosh F. Different strains of Saccharomyces cerevisiae differ in their effects on ruminal bacterial numbers in vitro and in sheep. 1995; Journal of Animal Science 73 1811-1818 - 54.
Newbold, C. J. "Probiotics for ruminants." (1996) - 55.
Newbold, C. J., and Eva Ramos-Morales. "Ruminal microbiome and microbial metabolome: effects of diet and ruminant host." animal 14, no. S1 (2020): s78-s86 - 56.
Nielsen, Jens. "Yeast systems biology: model organism and cell factory." Biotechnology journal 14, no. 9 (2019): 1800421 - 57.
Nurmi E, Rantala M (1973) New aspects of Salmonella infection in broiler production. Nature 241 210-211 - 58.
Paul SS, Kamra DN, Sastry VR, Sahu NP, Kumar A. Effect of phenolic monomers on biomass and hydrolytic enzyme activities of an anaerobic fungus isolated from wild nil gai (Baselophus tragocamelus). 2003; Letters in Applied Microbiology 36 377-381 - 59.
Poppy GD, Rabiee AR, Lean IJ, Sanchez WK, Dorton KL. A meta-analysis of the effects of feeding yeast culture produced by anaerobic fermentation of Saccharomyces cerevisiae on milk production of lactating dairy cows. 2012; Journal of Dairy Science 95 6027-6041 - 60.
Poppy GD, Rabiee AR, Lean IJ, Sanchez WK, Dorton KL. A meta-analysis of the effects of feeding yeast culture produced by anaerobic fermentation of Saccharomyces cerevisiae on milk production of lactating dairy cows. 2012; Journal of Dairy Science 95 6027-6041 - 61.
Robinson PH, Erasmus LJ. Effects of analyzable diet components on responses of lactating dairy cows to Saccharomyces cerevisiae based yeast products: A systematic review of the literature. 2009; Animal Feed Science and Technology 149 185-198 - 62.
Robinson PH, Erasmus LJ. Effects of analyzable diet components on responses of lactating dairy cows to Saccharomyces cerevisiae based yeast products: A systematic review of the literature. 2009; Animal Feed Science and Technology 149 185-198 - 63.
Russell, James B., and Robert B. Hespell. "Microbial rumen fermentation." Journal of Dairy Science 64, no. 6 (1981): 1153-1169 - 64.
Santra A, Karim S. Rumen manipulation to improve animal productivity. 2003; Asian Australasian Journal of Animal Sciences 16 748-763 - 65.
Shakira G, Atiya A Ahmed.I. Effects of Dietary Supplementation of Yeast (Saccharomyces cerevisiae) Culture on Growth Performance, Blood Parameters, Nutrient Digestibility and Fecal Flora of Dairy Heifers. 2015; The Journal of Animal and Plant Science 25 53-59 - 66.
Srinivasan, Prashanth, and Christina D. Smolke. "Biosynthesis of medicinal tropane alkaloids in yeast." Nature 585, no. 7826 (2020): 614-619 - 67.
Steele, Michael A., Greg B. Penner, and Frédérique Chaucheyras-Durand. "Development and physiology of the rumen and the lower gut: Targets for improving gut health." Journal of dairy science 99, no. 6 (2016): 4955-4966 - 68.
Swanson, Kelly S., Glenn R. Gibson, Robert Hutkins, Raylene A. Reimer, Gregor Reid, Kristin Verbeke, Karen P. Scott et al. "The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of synbiotics." Nature Reviews Gastroenterology & Hepatology 17, no. 11 (2020): 687-701 - 69.
Tapio, Ilma, Daniel Fischer, Lucia Blasco, Miika Tapio, R. John Wallace, Ali R. Bayat, Laura Ventto et al. "Taxon abundance, diversity, co-occurrence and network analysis of the ruminal microbiota in response to dietary changes in dairy cows." PloS one 12, no. 7 (2017): e0180260 - 70.
Tripathi VK, Sehgal JP, Puniya AK, Singh K. Hydrolytic activities of anaerobic fungi from wild blue bull (Boselaphus tragocamelus). 2007; Anaerobe 13: 36-39 - 71.
Tripathi VK, Sehgal JP, Puniya AK, Singh K. Hydrolytic activities of anaerobic fungi from wild blue bull (Boselaphus tragocamelus). 2007; Anaerobe 13: 36-39 - 72.
Ushida K, Jouany JP. Effect of defaunation on fibre digestion in sheep given two isonitrogenous diets. 1990; Animal Feed Science and Technology 29 153-158 - 73.
Wallace, R. J. "Ruminal microbiology, biotechnology, and ruminant nutrition: progress and problems." Journal of Animal Science 72, no. 11 (1994): 2992-3003 - 74.
Wallace, R. John, and C. James Newbold. "Probiotics for ruminants." In Probiotics, pp. 317-353. Springer, Dordrecht, 1992 - 75.
Wallace, R. John. "Rumen microbiology, biotechnology and ruminant nutrition: the application of research findings to a complex microbial ecosystem." FEMS microbiology letters 100, no. 1-3 (1992): 529-534 - 76.
Wiles, Travis J., Matthew Jemielita, Ryan P. Baker, Brandon H. Schlomann, Savannah L. Logan, Julia Ganz, Ellie Melancon, Judith S. Eisen, Karen Guillemin, and Raghuveer Parthasarathy. "Host gut motility promotes competitive exclusion within a model intestinal microbiota." PLoS biology 14, no. 7 (2016): e1002517 - 77.
Williams AG, Orpin CG. Polysaccharide-degrading enzymes formed by three species of anaerobic rumen fungi grown on a range of carbohydrate substrates.1987; Canadian Journal of Microbiology 33 418-426 - 78.
Williams AG, Orpin CG. Polysaccharide-degrading enzymes formed by three species of anaerobic rumen fungi grown on a range of carbohydrate substrates.1987; Canadian Journal of Microbiology 33 418-426 - 79.
Yang CM, Varga GA. The effects of continuous ruminal dosing with dioctyl sodium sulphosuccinate on ruminal and metabolic characteristics of lactating Holstein cows. 1993; British Journal of Nutrition 69 397-408 - 80.
Youngblut, Nicholas D., Georg H. Reischer, William Walters, Nathalie Schuster, Chris Walzer, Gabrielle Stalder, Ruth E. Ley, and Andreas H. Farnleitner. "Host diet and evolutionary history explain different aspects of gut microbiome diversity among vertebrate clades." Nature communications 10, no. 1 (2019): 1-15