• Journal of Microbiology and Biotechnology
• /
• v.32 no.3
• /
• pp.269-277
• /
• 2022

Human activities account for approximately two-thirds of global methane emissions, wherein the livestock sector is the single massive methane emitter. Methane is a potent greenhouse gas of over 21 times the warming effect of carbon dioxide. In the rumen, methanogens produce methane as a by-product of anaerobic fermentation. Methane released from ruminants is considered as a loss of feed energy that could otherwise be used for productivity. Economic progress and growing population will inflate meat and milk product demands, causing elevated methane emissions from this sector. In this review, diverse approaches from feed manipulation to the supplementation of organic and inorganic feed additives and direct-fed microbial in mitigating enteric methane emissions from ruminant livestock are summarized. These approaches directly or indirectly alter the rumen microbial structure thereby reducing rumen methanogenesis. Though many inorganic feed additives have remarkably reduced methane emissions from ruminants, their usage as feed additives remains unappealing because of health and safety concerns. Hence, feed additives sourced from biological materials such as direct-fed microbials have emerged as a promising technique in mitigating enteric methane emissions.

• Asian-Australasian Journal of Animal Sciences
• /
• v.8 no.6
• /
• pp.533-555
• /
• 1995

Direct-fed microbials (DFM) have been used to enhance milk production in lactating cattle and to increase feed efficiency and body weight gain in growing ruminants. Primary microorganisms that have been used as DFM for ruminants are fungal cultures including Aspergillus oryzae and Saccharomyces cerevisiae and lactic acid bacteria such as Lactobacillus or Streptococcus. Attempts have been made to determine the basic mechanisms describing beneficial effects of DFM supplements. Various modes of action for DFM have been suggested including : stimulation of ruminal microbial growth, stabilization of ruminal pH, changes in ruminal microbial fermentation pattern, increases in digestibility of nutrients ingested, greater nutrient flow to the small intestine, greater nutrient retention and alleviation of stress, however, these responses have not been observed consistently. Variations in microbial supplements, dosage level, production level and age of the animal, diet and environmental condition or various combinations of the above may partially explain the inconsistencies in response. This review summarizes production responses that have been observed under various conditions with supplemental DFM and also corresponding modification of ruminal fermentation and other changes in the gastrointestinal tract of ruminant animals.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.1
• /
• pp.162-165
• /
• 2002

With the objective of identifying the commercial potential of new direct-fed microbials, several temperature-tolerant strains were isolated from cane molasses at $39^{\circ}C$ and tested for their tolerance to pH, bile salts, and a mixture of volatile fatty acids (acetic acid:propionic acid:butyric acid=6.5:2.0:1.5). It was found that the isolated strain DY 252 grew very well up to pH 2.0 and was resistant to relatively high concentrations of bile salts. Among the strains tested, DY 252 was least inhibited by the addition of volatile fatty acids to the growth medium at $39^{\circ}C$. Accordingly, it would appear that strain DY 252, identified as yeast Issatchenkia orientalis, may be a potential candidate for use as a microbial feed additive.

• Journal of Animal Science and Technology
• /
• v.61 no.3
• /
• pp.122-137
• /
• 2019

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.12
• /
• pp.1657-1667
• /
• 2010

Direct-fed microbials (DFM) are dietary supplements that inhibit gastrointestinal infection and provide optimally regulated microbial environments in the digestive tract. As the use of antibiotics in ruminant feeds has been banned, DFM have been emphasized as antimicrobial replacements. Microorganisms that are used in DFM for ruminants may be classified as lactic acid producing bacteria (LAB), lactic acid utilizing bacteria (LUB), or other microorganisms including species of Lactobacillus, Bifidobacterium, Enterococcus, Streptococcus, Bacillus and Propionibacterium, strains of Megasphaera elsdenii and Prevotella bryantii and yeast products containing Saccharomyces and Aspergillus. LAB may have beneficial effects in the intestinal tract and rumen. Both LAB and LUB potentially moderate rumen conditions and improve feed efficiency. Yeast DFM may reduce harmful oxygen, prevent excess lactate production, increase feed digestibility, and improve fermentation in the rumen. DFM may also compete with and inhibit the growth of pathogens, stimulate immune function, and modulate microbial balance in the gastrointestinal tract. LAB may regulate the incidence of diarrhea, and improve weight gain and feed efficiency. LUB improved weight gain in calves. DFM has been reported to improve dry matter intake, milk yield, fat corrected milk yield and milk fat content in mature animals. However, contradictory reports about the effects of DFM, dosages, feeding times and frequencies, strains of DFM, and effects on different animal conditions are available. Cultivation and preparation of ready-to-use strict anaerobes as DFM may be cost-prohibitive, and dosing methods, such as drenching, that are required for anaerobic DFM are unlikely to be acceptable as general on-farm practice. Aero-tolerant rumen microorganisms are limited to only few species, although the potential isolation and utilization of aero-tolerant ruminal strains as DFM has been reported. Spore forming bacteria are characterized by convenience of preparation and effectiveness of DFM delivery to target organs and therefore have been proposed as DFM strains. Recent studies have supported the positive effects of DFM on ruminant performance.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.10
• /
• pp.1411-1416
• /
• 2004

The objective of this work was to isolate a microorganism, able to produce high lactate dehydrogenase (LDH) activity, for use as a microbial feed additive. The LDH is an important enzyme for lactate conversion in the rumen, thereby possibly overcoming lactic acidosis owing to sudden increases of cereal in the diets of ruminants. In the present study, various bacterial strains were screened from a variety of environments. Among the isolated microorganisms, strain FFy 111-1 isolated from a Korean traditional fermented vegetable food called Kimchi showed the highest enzyme activity, along with retaining strong enzyme activity even in rumen fluid in vitro. Based on morphological and biochemical characteristics as well as compositions of cellular fatty acids plus API analyses, this strain was identified as Lactobacillus sp. The optimum temperature and pH for growth were found to be 30$^{\circ}C$ and pH 6.5, respectively. A maximum cell growth of 2.2 at $A_{650}$ together with LDH activity of 2.08 U per mL was achieved after 24 h of incubation. Initial characterization of FFy 111-1 suggested that it could be a potential candidate for use as a direct-fed microbial in the ruminant animals.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.5
• /
• pp.643-649
• /
• 2011

The objective of this study was to determine the effect of feeding direct-fed microbials (DFM) on the growth performance and prophylaxis of calf diarrhea during the pre-weaning period as an alternative to antibiotics. A multi-species DFM was formulated including three lactic acid bacteria (Lactobacillus salivarius Ls29, Pediococcus acidilactia Pa175, and L. plantarum Lp177), three Bacillus strains (B. subtilis T4, B. polymyxa T1 and SM2), one yeast, Saccharomyces boulardii, and a nonpathogenic E. coli Nissle 1917. Lactic acid bacteria and Bacillus strains were selected based on the antibacterial activity against various animal pathogens, especially pathogenic E. coli using agar diffusion methods in vitro. Test and control groups were fed milk replacer and calf starter supplemented with DFM ($10^9$ cfu each of eight species/d/head, n = 29) or with antibiotics (0.1% neomycin sulfate in milk replacer and Colistin 0.08% and Oxyneo 110/110 0.1% in calf starter, n = 15), respectively. Overall fecal score and the incidence rate of diarrhea were reduced in the DFM group compared to the antibiotics one. About 40% of calves in antibiotic group suffered from diarrhea while in DFM group only 14% showed diarrhea. There was no difference in the average daily gain and feed efficiency of two groups. The hematological levels of calves were all within the normal range with no significant difference. In conclusion, the feeding of multispecies DFM during the pre-weaning period could reduce calf diarrhea and there was no difference in the growth performance between the groups, thus showing the potential as an alternative to antibiotics.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.4
• /
• pp.493-499
• /
• 2011

The objective of this study was to find the way to prolong the storage time of sawdust-based oyster mushroom (Pleurotus osteratus) spent substrate (OMSS) by fermenting with potential probiotic microorganisms to recycle the otherwise waste of mushroom farms. To this purpose, lactic acid bacteria (LAB) were screened to select the best lactic acid-producing strains. Three strains of LAB (Lactobacillus plantarum Lp1', Pediococcus acidilacticii Pa193, L. plantarum Lp2M) were selected and in mixture they lowered the pH of the fermented OMSS to 3.81. fOMSS (fermented sawdust-based oyster mushroom spent substrate) could be stored at room temperature for at least 17 days without any deterioration of feed quality based on the pH, smell, and color. In dry matter disappearance rate in situ, commercial TMR (total mixed ration), OMSS and OMMM (oyster mushroom mycelium mass) showed no significant differences between the samples after 6, 12 and 24 h incubation except for 48 h. Two separate field studies were performed to test the effects of fOMSS supplement on the growth performance of postweaning Holstein calves. Field trials included groups of animals feeding calf starter supplemented with: Control (no supplement), AB (colistin 0.08% and oxyneo 110/110 0.1%), fOMSS (10% fOMSS) and fConc (10% fermented concentrate) and DFM (direct-fed microbials, average $10^9$ cfu for each of three LAB/d/head). Growth performance (average daily gain and feed efficiency) of the fOMSS supplement group was higher than that of AB followed by fConc and DFM even though there was no statistically significant difference. The Control group was lower than any other group. Various hematological values including IgG, IgA, RBC (red blood cell), hemoglobin, and hematocrit were measured every 10 days to check any unusual abnormality for all groups in trial I and II, and they were within a normal and safe range. Our results suggest that sawdust-based OMSS could be recycled after fermentation with three probiotic LAB strains as a feed supplement for post-weaning calves, and fOMSS has the beneficial effects of an alternative to antibiotics for a growth enhancer in dairy calves.

• Microbiology and Biotechnology Letters
• /
• v.36 no.2
• /
• pp.87-95
• /
• 2008

Probiotics are live organisms that when administered in adequate amounts confer a health benefit on hosts. The administration of direct-fed microbials (DFM) such as lactobacilli and bacillus, may be a more direct approach to beneficially alter gastrointestinal microflora than altering dietary ingredients or supplementing with growth-promoting levels of antibiotics. It is apparent that microbes have an important influence on immune development and resistance to infection; that microbes are not static colonizers of our bodies, but are dynamic, symbiotic coresidents. And it can improve the surrounding environments; decrease the malodor caused by degrade the excrement. Recently, new paradigm such as environment protection and safe food have been settled. In domestic farm house, there is a great demand for probiotics as a substitute of antibiotics for the improvement of environmental quality and the production of a competitive goods. Probiotics circulated in a country have three categories: an animal medicine permitted by national veterinary research quarantine service (NVRQS), a support feed registered in city or country house, and not-registered goods. However, lots of unqualified goods were produced and circulated. And thus, it is in urgent need of evaluating the present situation and effect of probiotics. This study was conducted to evaluate the system of a probiotics as a livestock-environment improving agents for the alternation of antibiotics and quality control of it.

• Korean Journal of Poultry Science
• /
• v.31 no.2
• /
• pp.85-91
• /
• 2004

This study was conducted to investigate the effects of dietary direct-fed microbials(DFM) on the growth performance and nutrient digestibility in broiler chickens. A total of two hundred eighty eight broiler chickens were randomly allocated into six treaments with four replications and fed for five weeks. Dietary treatments included 1) CON (basal diet), 2) DFM-1(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri), 3) DFM-2(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus plantarum), 4) DFM-3(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum), 5) DFM-4(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum ＆ Yeast), 6) DFM-5(basal diet + 0.2% Enterococcus sp. ＆ Lactobacillus reuteri ＆ Lactobacillus plantarum ＆ Bacillus subtilis). During the period of 1∼3weeks, average daily gain (ADG) and Feed/Gain were not significant different among treatments. In the later(3∼5weeks) and overall period(l∼ 5weeks), ADG and Feed/Gain tended to be improved in DFM treatments compared to the control. However, there were no significant differences among DFM complexes and between control and DFM treatments. The broilers fed DFM-3 diet was showd poor growth performance compared to the broilers fed DFM-l diet and similar to the broilers fed DFM-2 diet but there was no significant differences. The treatments of DFM-4 diet added Yeast and DFM-5 added Bacillus subtilis were improved in ADG and Feed/gain but no significant differences were found and also there was no specific DFM treatments in experiment period. In digestibility, the broiler chicks fed DFM treatments tended to improve N digestibility compared to control treatment. However, they were not significantly different among the treatments. In conclusion, DFM tended to improve growth performance in later stage of broiler.