Rumen Microbial Population Research Articles

Comparative Evaluation of Extruded Complete Feeds based on Finger Millet (Eleusine coracana) Straw, Areca (Areca catechu) Sheath and Maize (Zea mays) Cob in Mandya Lambs

Background: Although crop residues rich in lignocellulose are a potential source of energy, their utilization is limited due to lack of lignolytic activity of the rumen microbial population. Feed processing by heat treatment is known to break the ligno-cellulolse complexes, in which extrusion has been reported as one of the best processing techniques to improve the nutritional value and efficient utilization of complete diets. A comparative evaluation of extruded complete feed based on finger millet straw, a conventional crop residue, along with areca sheath and maize cob has been taken up in this study. Methods: The extruded complete feed was prepared using roughage and concentrate at proportion of 40:60, respectively. Twenty four Mandya lambs of about 3 to 4 months of age with body weight ranging from 7.8 to 12.9 kg were divided into three groups of eight each in a completely randomized design. Feeding trial was carried out for 12 weeks. The animals were randomly assigned to one of the treatment groups viz., T1 (Finger millet straw based extruded complete feed), T2 (Areca sheath based extruded complete feed) and T3 (Maize cob based extruded complete feed). Digestion trial was conducted using 5 animals in each group during the last week of the growth trial. Result: Analysis of chemical composition (%) revealed that, maize cob and areca sheath were comparable with finger millet straw except that the maize cob contained lower total ash (2.52 v/s 8.61) and higher NDF and hemicellulose content (86.66 v/s71.61; 29.79 v/s17.18). Rumen in vitro net gas (ml / 200 mg DM / 24 h) production and energy density (ME MJ / kg DM) was higher in areca sheath and maize cob as compared to finger millet straw. There was significant difference in total DMI (g/d and g/kgW0.75) among the treatment groups (P£0.05). There was also a significant difference in OM, CP, EE and ADF intake (P£0.05). The ADG (g) and FCR (g DMI/ g BW gain) for T1, T2 and T3 groups were statistically non-significant. The mean apparent digestibility (%) of DM, OM, CP, NDF and ADF was significantly different among the treatment groups(P£0.01). The per cent Digestible organic matter in dry matter (DOMDM) (T1:70.89,T2:76.13and T3:63.33) was also significantly different among the treatments (P£0.01). It was concluded that the growth rate of lambs fed finger millet straw, areca sheath and maize cob based extruded complete feeds was comparable and could be utilized to sustain production performance of growing Mandya lambs.

Phytochemicals: potential alternative strategy to fight Salmonella enterica serovar Typhimurium.

The rise of multidrug resistant (MDR) microorganisms is a great hazard worldwide and has made it difficult to treat many infectious diseases adequately. One of the most prevalent causes of outbreaks of foodborne illness worldwide is Salmonella. The ability of this and other harmful bacteria to withstand antibiotics has recently proven crucial to their effective control. Since the beginning of time, herbal medicines and phytochemicals have been employed for their potent antibacterial action and there is a growing trend toward the production of plant based natural products for the prevention and treatment of pathogenic infections. Numerous phytochemicals have been proven effective against the molecular determinants responsible for attaining drug resistance in pathogens like efflux pumps, membrane proteins, bacterial cell communications and biofilms. The medicinal plants having antibacterial activity and antibiotics combination with phytochemicals have shown synergetic activity against Salmonella enterica serovar Typhimurium. The inhibitory effects of tannins on rumen proteolytic bacteria can be exploited in ruminant nutrition. Improved control of the rumen ecology and practical use of this feed additive technology in livestock production will be made possible by a better knowledge of the modulatory effects of phytochemicals on the rumen microbial populations in combination with fermentation. This review focuses on the development of antibacterial resistance in Salmonella, the mechanism of action of phytochemicals and the use of phytochemicals against S. enterica serovar Typhimurium. The advances and potential future applications of phytochemicals in the fight against resistant are also discussed.

Effects on rumen pH and feed intake of a dietary concentrate challenge in cows fed rations containing pH modulators with different neutralizing capacity

Forty-five Holstein lactating cows (41 ± 8.8 kg/d of milk yield, 96 ± 35.6 days in milk, and 607 ± 80.4 kg of body weight) were enrolled in this study to assess the effects of diets supplemented with sodium bicarbonate or a magnesium-based product and their corresponding differences in dietary cation-anion difference (DCAD) on rumen pH, rumen microbial population, and milk performance of dairy cattle exposed to an induced decrease in rumen pH through a dietary challenge. Cows were randomly allocated to 3 total mixed rations (TMR) differing in the type of supplement to modulate rumen pH: (1) control, no supplementation; (2) SB, supplemented with 0.82% of sodium bicarbonate with a neutralizing capacity (NC) of 12 mEq/g; and (3) MG, supplemented with 0.25% of magnesium oxide (pHix-Up, Timab Magnesium) with a NC of 39 mEq/g. Thus, SB and MG rations had, in theory, the same NC. The 3 TMR differed for control, SB, and MG in their DCAD-S (calculated considering Na, K, Cl, and S), which was on average 13.2, 21.2, and 13.7 mEq/100 g, respectively, or DCAD-Mg (calculated accounting for Mg, Ca, and P), which was 31.4, 41.2, and 35.2 mEq/100 g, respectively. The study lasted 63 d, with the first 7 d serving as a baseline, followed by a fortnightly progressive decrease of dietary forage-to-concentrate ratio (FCR) starting at 48:52, then 44:56, then 40:60, and finishing at 36:64. Individual dry matter intake (DMI) was recorded daily. Seven cows per treatment were equipped with electronic rumen boluses to monitor rumen pH. Control and SB cows consumed less dry matter (DM; 23.5 ± 0.31 kg/d) than MG cows (25.1 ± 0.31 kg/d) when fed dietary FCR of 44:56 and 40:60. Energy-corrected milk decreased from 40.8 ± 1.21 to 39.5 ± 1.21 kg/d as dietary FCR decreased, independently of dietary treatments. Rumen pH decreased and the proportion of the day with rumen pH <5.8 increased as dietary FCR decreased, and at low dietary FCR (i.e., 36:64) rumen pH was greater in MG cows than in control and SB cows. Reducing the DCAD-S from 28 to 18 mEq/100 g or the DCAD-Mg from 45 to 39 mEq/kg had no effects on DMI or milk yield. Cows supplemented with ∼62 g/d of magnesium oxide (pHix-Up) maintained a greater rumen pH and consumed more DM than cows supplemented with ∼200 g/d of sodium bicarbonate when fed a diet with low FCR.

Modulation of milking performance, methane emissions, and rumen microbiome on dairy cows by dietary supplementation of a blend of essential oils

Cattle represent a high contribution of the livestock's greenhouse gas emissions, mainly in the form of methane. Essential oils are a group of plant secondary metabolites obtained from volatile fractions of plants that have been shown to exert changes in the rumen fermentation and may alter feed efficiency and to reduce methane production. The objective of this study was to investigate the effect on rumen microbial population, CH4 emissions and milking performance of a mixture of essential oils (Agolin Ruminant, Switzerland) incorporated daily in the ration of dairy cattle. Forty Holstein cows (644 ± 63.5 kg of BW producing 41.2 ± 6.44 kg/d of milk with 190 ± 28.3 DIM) were divided into two treatments (n = 20) for 13 wk and housed in a single pen equipped with electronic feeding gates to control access to feed and monitor individual DM intake (DMI) on a daily basis. Treatments consisted of no supplementation (Control) or supplementation of 1 g/d of a blend of essential oils (BEOs) fed in the TMR. Individual milk production was recorded using electronic milk meters on a daily basis. Methane emissions were recorded using sniffers at the exit of the milking parlour. At day 64 of the study, a sample of rumen fluid was collected from 12 cows per treatment after the morning feeding using a stomach tube. There were no differences in DMI, milk yield, or milk composition between the two treatments. However, cows on BEO exhaled less CH4 (444 ± 12.5 l/d) than cows on Control (479 ± 12.5 l/d), and exhaled less (P < 0.05) CH4/kg of DM consumed (17.6 vs 20.1 ± 0.53 l/kg, respectively) from the first week of study, with no interaction with time, which suggests a fast action of BEO of CH4 emissions. Rumen relative abundance of Entodonium increased, and those of Fusobacteria, Chytridiomycota, Epidinium, and Mogibacterium decreased in BEO compared with Control cows. Supplementing 1 g/d of BEO reduces CH4 emissions on absolute terms (l/d) and diminishes the amount of CH4 produced by unit of DM consumed by cows relatively soon after the first supplementation, and the effect is sustained over time without impacting intake or milking performance.

The inhibition of high ammonia to in vitro rumen fermentation is pH dependent.

Ammonia is an important rumen internal environment indicator. In livestock production, feeding a large amount of non-protein nitrogen to ruminants will create high ammonia stress to the animals, which increases the risk of ammonia toxicity. However, the effects of ammonia toxicity on rumen microbiota and fermentation are still unknown. In this study, an in vitro rumen fermentation technique was used to investigate the effects of different concentrations of ammonia on rumen microbiota and fermentation. To achieve the four final total ammonia nitrogen (TAN) concentrations of 0, 8, 32, and 128 mmol/L, ammonium chloride (NH4Cl) was added at 0, 42.8, 171.2, and 686.8 mg/100 mL, and urea was added at 0, 24, 96, and 384 mg/100 mL. Urea hydrolysis increased, while NH4Cl dissociation slightly reduced the pH. At similar concentrations of TAN, the increased pH of the rumen culture by urea addition resulted in a much higher free ammonia nitrogen (FAN) concentration compared to NH4Cl addition. Pearson correlation analysis revealed a strong negative correlation between FAN and microbial populations (total bacteria, protozoa, fungi, and methanogens) and in vitro rumen fermentation profiles (gas production, dry matter digestibility, total volatile fatty acid, acetate, propionate, etc.), and a much weaker correlation between TAN and the above indicators. Additionally, bacterial community structure changed differently in response to TAN concentrations. High TAN increased Gram-positive Firmicutes and Actinobacteria but reduced Gram-negative Fibrobacteres and Spirochaetes. The current study demonstrated that the inhibition of in vitro rumen fermentation by high ammonia was pH-dependent and was associated with variations of rumen microbial populations and communities.

Effects of inoculating feruloyl esterase-producing Lactiplantibacillus plantarum A1 on ensiling characteristics, in vitro ruminal fermentation and microbiota of alfalfa silage

BackgroundFerulic acid esterase (FAE)-secreting Lactiplantibacillus plantarum A1 (Lp A1) is a promising silage inoculant due to the FAE’s ability to alter the plant cell wall structure during ensiling, an action that is expected to improve forage digestibility. However, little is known regarding the impacts of Lp A1 on rumen microbiota. Our research assessed the influences of Lp A1 in comparison to a widely adopted commercial inoculant Lp MTD/1 on alfalfa’s ensilage, in vitro rumen incubation and microbiota.ResultsSamples of fresh and ensiled alfalfa treated with (either Lp A1 or Lp MTD/1) or without additives (as control; CON) and ensiled for 30, 60 and 90 d were used for fermentation quality, in vitro digestibility and batch culture study. Inoculants treated silage had lower (P < 0.001) pH, acetic acid concentration and dry matter (DM) loss, but higher (P = 0.001) lactic acid concentration than the CON during ensiling. Compared to the CON and Lp MTD/1, silage treated with Lp A1 had lower (P < 0.001) aNDF, ADF, ADL, hemicellulose, and cellulose contents and higher (P < 0.001) free ferulic acid concentration. Compared silage treated with Lp MTD/1, silage treated with Lp A1 had significantly (P < 0.01) improved ruminal gas production and digestibility, which were equivalent to those of fresh alfalfa. Real-time PCR analysis indicated that Lp A1 inoculation improved the relative abundances of rumen’s total bacteria, fungi, Ruminococcus albus and Ruminococcus flavefaciens, while the relative abundance of methanogens was reduced by Lp MTD/1 compared with CON. Principal component analysis of rumen bacterial 16S rRNA gene amplicons showed a clear distinction between CON and inoculated treatments without noticeable distinction between Lp A1 and Lp MTD/1 treatments. Comparison analysis revealed differences in the relative abundance of some bacteria in different taxa between Lp A1 and Lp MTD/1 treatments. Silage treated with Lp A1 exhibited improved rumen fermentation characteristics due to the inoculant effects on the rumen microbial populations and bacterial community.ConclusionsOur findings suggest that silage inoculation of the FAE-producing Lp A1 could be effective in improving silage quality and digestibility, and modulating the rumen fermentation to improve feed utilization.

Variety of rumen microbial populations involved in biohydrogenation related to individual milk fat percentage of dairy cows.

Our objective was to investigate the contribution of the rumen microbiome on the individual milk fat percentage (MFP) of Holstein dairy cows under the same nutritional and management conditions. From 92 early lactation dairy cows, the top 10 with the highest MFP (HF; n = 10) and the last 10 with the lowest MFP (LF; n = 10) were selected for the study. As a result, the milk trans-10, cis-12 C18:2 content was significant lower in the HF group than that in the LF group (P < 0.001). The rumen acetate to propionate ratio was significant higher in the HF group than that in the LF group (P = 0.035). According to the results of 16S rRNA gene sequencing, a minor but significant difference existed between the groups (P = 0.040). Three genera of the family Lachnospiraceae and four genera of the order Bacteroidales were identified to be the biomarkers for the LF group and HF group in the LEfSe analysis, respectively. Three microbial modules enriched by the family Lachnospiraceae were positively related to the milk trans-10, cis-12 C18:2 content (r s > 0.60, P < 0.05). According to the results of shotgun metagenome sequencing, three kinds of linoleic acid (LA) isomerase genes were present in the gene pools of the rumen microbiome. Among them, the relative abundance of Bifidobacterium LA isomerase (BBI) was higher in the HF group than that in the LF group (P = 0.007). Three metagenome-assembled genomes (MAGs) with LA isomerase genes were positively correlated to the milk trans-10, cis-12 C18:2 content (r s > 0.40, P < 0.05). Furthermore, all of these three MAGs were found to be able to produce lactate. Taken together, these results indicate that the increased relative abundance of microbial population with the trans-10 biohydrogenation pathway within the rumen microbiome contributes to the decrease of MFP via the increase of rumen trans-10, cis-12 C18:2 production. This study provides a new perspective for the development of measures for improving the milking performance of dairy cows.

Effect of heat stress on rumen microbial population and milk production in lactating dairy cattle - Review

Effect of heat stress on rumen microbial population and milk production in lactating dairy cattle - Review

Effects of diet and castration on fatty acid composition and volatile compounds in the meat of Korean native black goats.

This study determined the effects of dietary treatments and castration on meat quality, fatty acids (FAs) profiles, and volatile compounds in Korean native black goats (KNBG, Capra hircus coreanae), including the relationship between the population of rumen microbiomes and meat FA profiles. Twenty-four KNBG (48.6±1.4 kg) were randomly allocated to one of four treatments arranged into a 2×2 factorial structure. The factors were dietary forage to concentrate ratio (high forage [HF, 80:20] and low forage [LF, 20:80]), and a castration treatment (castration [CA] vs non-castration [NCA]). Among meat quality traits, the CA group exhibited a higher percentage of crude fat and water holding capacity (p<0.05). The profiles of the saturated fatty acid (SFA) in meat sample derived from CA KNBG showed a significantly lower percentage compared to NCA individuals, due to the lower proportion of C14:0 and C18:0. Feeding a high-forage diet to KNBG increased the formation of C18:1n7, C18:3n3, C20:1n9, C22:4n6 in meat, and polyunsaturated fatty acid (PUFA) profiles (p<0.05). Consequently, the n6:n3 ratio declined (p<0.05). There was an interaction between dietary treatment and castration for formation of C20:5n3 (p<0.05), while C18:1n9, C22:6n3, monounsaturated fatty acid (MUFA) and the MUFA:SFA ratio were influenced by both diet and castration (p<0.05). Nine volatile compounds were identified and were strongly influenced by both dietary treatments, castration (p<0.05), and their interaction. In addition, principal component analysis (PCA) revealed distinctly different odor patterns in the NCA goats fed LF diets. Spearman correlation analysis showed a high correlation between rumen bacteria and meat PUFAs. These results suggest the essential effects of the rumen microbial population for the synthesis of meat FAs and volatile compounds in KNBG meat, where dietary intake and castration also contribute substantially.

Forages and pastures symposium: forage biodegradation: advances in ruminal microbial ecology.

The rumen microbial ecosystem provides ruminants a selective advantage, the ability to utilize forages, allowing them to flourish worldwide in various environments. For many years, our understanding of the ruminal microbial ecosystem was limited to understanding the microbes (usually only laboratory-amenable bacteria) grown in pure culture, meaning that much of our understanding of ruminal function remained a "black box." However, the ruminal degradation of plant cell walls is performed by a consortium of bacteria, archaea, protozoa, and fungi that produces a wide variety of carbohydrate-active enzymes (CAZymes) that are responsible for the catabolism of cellulose, hemicellulose, and pectin. The past 15 years have seen the development and implementation of numerous next-generation sequencing (NGS) approaches (e.g., pyrosequencing, Illumina, and shotgun sequencing), which have contributed significantly to a greater level of insight regarding the microbial ecology of ruminants fed a variety of forages. There has also been an increase in the utilization of liquid chromatography and mass spectrometry that revolutionized transcriptomic approaches, and further improvements in the measurement of fermentation intermediates and end products have advanced with metabolomics. These advanced NGS techniques along with other analytic approaches, such as metaproteomics, have been utilized to elucidate the specific role of microbial CAZymes in forage degradation. Other methods have provided new insights into dynamic changes in the ruminal microbial population fed different diets and how these changes impact the assortment of products presented to the host animal. As more omics-based data has accumulated on forage-fed ruminants, the sequence of events that occur during fiber colonization by the microbial consortium has become more apparent, with fungal populations and fibrolytic bacterial populations working in conjunction, as well as expanding understanding of the individual microbial contributions to degradation of plant cell walls and polysaccharide components. In the future, the ability to predict microbial population and enzymatic activity and end products will be able to support the development of dynamic predictive models of rumen forage degradation and fermentation. Consequently, it is imperative to understand the rumen's microbial population better to improve fiber degradation in ruminants and, thus, stimulate more sustainable production systems.

Impact of Enzymatic Hydrolyzed Protein Feeding on Rumen Microbial Population, Blood Metabolites and Performance Parameters of Lactating Dairy Cows

Impact of Enzymatic Hydrolyzed Protein Feeding on Rumen Microbial Population, Blood Metabolites and Performance Parameters of Lactating Dairy Cows

IMPLEMENTATION OF ESSENTIAL BIOSTIMULATOR TECHNOLOGY IN SUPPLEMENTARY FEED AS A MIXTURE OF REINFORCING FEED ON HAEMATOLOGICAL AND NUTRIENT PROFILES OF BEEF CATTLE SERUM (CASE STUDY OF BEEF CATTLE FATTENING ON PEOPLE'S LIVESTOCK)

The national meat self-sufficiency program in Indonesia aims to increase the cattle population to meet the country's meat consumption. Beer dregs are a potential alternative feed supplement, as they contain high crude protein and soluble carbohydrates that can affect the rumen microbial population. In addition, essential oil biostimulators derived from citronella are added to the feed as a mixture of reinforcing feed to support cattle health and productivity. This study investigates the effect of essential biostimulators in supplementary feed as a mixture of reinforcing feed on the haematological and nutrient profiles of beef cattle serum, using the case study of beef cattle fattening in People's Livestock. Results showed that the addition of citronella essential oil improved nutrient digestibility and rumen health, and the combination of beer dregs and essential biostimulators positively impacted the haematological and nutrient profiles of beef cattle serum.

Management of Enteric Methane Emissions in Ruminants Using Feed Additives: A Review.

In ruminants' metabolism, a surplus of hydrogen is removed from the reduction reaction of NAD+ (nicotinamide adenine dinucleotide) by the formation of methane by methanogenic bacteria and archaea methanogens. The balance of calculations between VFA (volatile fatty acids), CO2, and CH4 indicates that acetate and butyrate play a role in methane production, while the formation of propionate maintains hydrogen and therefore reduces methane production. CH4 formation in ruminant livestock is not desired because it reduces feed efficiency and contributes to global warming. Therefore, numerous strategies have been investigated to mitigate methane production in ruminants. This review focuses on feed additives which have the capability of reducing methane emissions in ruminants. Due to the environmental importance of methane emissions, such studies are needed to make milk and meat production more sustainable. Additionally, the additives which have no adverse effects on rumen microbial population and where the reduction effects are a result of their hydrogen sink property, are the best reduction methods. Methane inhibitors have shown such a property in most cases. More work is needed to bring methane-reducing agents in ruminant diets to full market maturity, so that farmers can reap feed cost savings and simultaneously achieve environmental benefits.

Effect of Heat Stress on Rumen Microbial Diversity and Fermentation Pattern in Buffalo

In this study, changes in rumen microbiome and fermentation were examined during heat stress (HS) in buffaloes. Six buffalo heifers were exposed to thermoneutral ( THI = 72 ) and HS ( THI = 87 – 90 ) conditions for 6 h between 10 AM and 4 PM for 21 days in the climatic chamber. A digestibility trial with four-day collection period was conducted at the end of the study, and rumen liquor was collected on day 21. At the phylum level, an increased ( p &lt; 0.05 ) abundance of Firmicutes and a decreased ( p &lt; 0.05 ) abundance of Proteobacteria and Planctomycetes were observed during HS compared to thermoneutral conditions. The abundance of 6 different genera of phylum Firmicutes, YRC22 (phylum Bacteroidetes), and Stenotrophomonas (phylum Proteobacteria) was increased ( p &lt; 0.05 ), whereas B. firmus, Lysinibacillus, Bacteroides unclassified genus (family Enterobacteriaceae), and Methanobrevibacter decreased ( p &lt; 0.05 ) during HS compared to control. Eight new genera from four different phyla were detected after HS exposure, whereas one genus was not detected in the rumen after HS exposure, which was present during thermoneutral conditions. Dry matter intake, volatile fatty acid concentration, and digestibility did not change ( p &gt; 0.05 ) during HS. It can be concluded that the resilience of the rumen microbial population invokes adaptive responses by changing their abundance to minimize the adverse effects on fermentation and digestibility in buffalo heifers.

PENGARUH PEMBERIAN POLIFENOL DARI TANAMAN HERBAL SEBAGAI NATURAL FEED ADDITIVE TERHADAP PERFORMA ANAK KAMBING DAN DOMBA

The antibiotics as feed additive had been prohibited by the government regulation, because it was feared that it would pose a risk to livestock and residues in the products they produce. The ban is an opportunity for the development of innovations in feeding, such as the use of herbal plants as natural feed additives (NFA). The provision of NFA had been carried out by several researchers to the performance of kids and lambs. Kids and lambs are one of the key stages of successful sheep and goat farming. Kids and lambs that are healthy and have good performance will certainly be good breeds for livestock farming. Utilization of herbs and spices containing polyphenolic compounds has various effects on livestock, especially kids and lambs. The benefits or effects of NFA on kids and lambs are summarized in several studies, namely faster livestock growth, increased feed digestibility, feed efficiency, and economic efficiency. In addition, NFA also affects metabolic function and immunity, and reduces methane gas emissions without disturbing the rumen microbial population. Meat produced from kids and lambs supplemented with NFA also showed increased oxidative stability and increased PUFA and MUFA levels. Keywords: additive, herb, polyphenol, goat, lamb, kids

Use of feed additives to improve feed efficiency and growth of feedlot cattle

The producers must observe feed efficiency (FE) and profitability in feedlot cattle under scenarios of high production costs associated with feeding. The most efficient and persistant way to change FE is using genetic tools. However, genetic selection in cattle is slow compared to the use of feed addititves, which work to stabilize ruminal pH, induce beneficial changes in the rumen microbial population, and increase efficiency in energy and protein metabolism. The literature is extensive about antibiotics, ionophores, and non-ionophores increasing FE. Nowadays, the use of "naturals" products as growth promoters has gained great relevance, and promising results has been reported. ). Therefore, this study aimed to review the use of feed additives in beef cattle feeding.

Implications of phyto-feed additives supplementation in buffalo calves on rumen fermentation pattern and microbial population

Natural phyto-feed additives have been identified as a potential rumen fermentation modifier by in vitro studies and by few short-term in vivo trials. However, information on impact on animal performance by their long-term administration is still inadequate. In light of this, the present study was undertaken to examine the rumen fermentation pattern, rumen microbial enzymes and microbial profiles as influenced by long term supplementation of phyto-feed additives to buffalo calves. A six months feeding trial was conducted on 20 male buffaloes (165±4 kg body weight), divided into four groups and fed on diet supplemented with no additive (T0, control), with feed additive FAI @ 1% of dry matter intake (DMI) (T1), with FAII @ 1 ml/kg DMI (T2) and with FAI and FAII switched alternatively after every 15 days (T3). No significant effect was observed on rumen fermentation pattern as well as carboxymethylcellulase, avicelase, xylanase, acetyl esterase, and protease activities in the rumen of buffalo calves. The population density of methanogens, fungi, Ruminococcus flavefaciens, and R. albus decreased significantly in T3 where FAI and FAII were fed alternately, but Fibrobacter succinogenes decreased significantly in T2 where FAII was fed. When compared to the control, the microscopic count of protozoa decreased in all the three supplemented groups. It can be concluded that rumen fermentation, including rumen metabolites and microbial enzymes, were unaffected; however, phyto-feed additives exhibited changes in rumen microbes.

PSXVI-5 Rumen Parameters and Microbial Population Changes in Fattening Holstein Heifers fed with Nitrate-Contaminated Water

Abstract The aim of this study was to evaluate the effect of drinking water nitrate concentration on rumen parameters and its microbial population that may affect greenhouse gases in fattening cattle. Holstein heifers (n = 24; 161 ± 19.9 kg of initial BW, and 183 ± 25.3 d of age) were housed individually and fed ad libitum. Animals were assigned to 4 treatments according to nitrate concentration in drinking water: 1) Control (n=6), without NO3-; 2) Low (n=6), with 44 mg/L of NO3-; 3) Moderate (n=6), with 110 mg/L of NO3-, and 4) High (n=6), with 220 mg/L of NO3-. After 14 and 168 days the ruminal content was sampled to determine pH, volatile fatty acids (VFA), nitrate and nitrite concentration, and rumen microbiota (except for Moderate). To assess the rumen microbiota, DNA-based qPCR of total bacterial population (16S rRNA), dissimilatory sulfate-reducing prokaryotes (aprA), ammonia-oxidizing bacteria and archaea (amoA-AOB and amoA-AOA), typical complete denitrifiers (nosZ-clade I linked to the transformation of N2O to N2), and anammox bacteria (hzo) was determined. Rumen pH, VFA, nitrate and nitrite were analyzed with a mixed effects model. Rumen microbial populations were statistically treated by analysis of variance applying pairwise comparisons (Fisher's least). Rumen pH, VFA, nitrate and nitrite were not affected by nitrate concentration in drinking water; however, rumen nitrite concentrations were greater (P &amp;lt; 0.01) in d 14 than in d 168 (32.1 vs. 6.3 ± 4.20 mg/L, respectively). Nitrate drinking water concentration did not affect rumen microbial populations, except for complete-denitrifying population (nosZ-clade I) which were slightly greater (P=0.01) in High than in Control in d 168. In conclusion, nitrate-contaminated water did not show a significant impact on rumen parameters and microbial populations but increased the bacterial denitrifying potential after a long term, which could decrease ruminal N2O emissions and nitrite ruminal accumulation in fattening heifers.

201 Forage Biodegradation: Advances in Ruminal Microbial Ecology

Abstract The rumen microbial ecosystem provides ruminant animals a selective advantage, the ability to utilize forages, which allows ruminant animals to flourish around the world in a wide variety of environments. The ability of the microbial population to convert sunlight captured in forages to high quality meat, milk, and fiber has been recognized for many years. However, the rumen microbial population composition and degradative activity has remained a “black box” with only the most active (and most amenable to laboratory growth) cellulolytic and hemicellulolytic organisms being recognized and understood. The limitation of reliance upon growth of forage degrading organisms in a test tube in order to measure the catabolic activity, severely limited the development of knowledge of the microbial ecology of ruminal forage degradation. The past 15 years has seen the development and implementation of numerous Next-Generation Sequencing (NGS) approaches, which have greatly contributed to a better understanding of the microbial ecology of ruminants fed a variety of forages. NGS has provided new insights into changes in the microbial population of ruminants fed different diets, or undergoing dietary changes. The ability to take a “snapshot” of the composition of the ruminal microbial population has furthered our understanding of the impacts of forage maturity, forage type, and phytochemicals on the degradation and fermentation of forages. We now better understand the microbial pathways that are enriched by feeding of forages and are impacted by forage quality or composition, which can further our understanding of metabolomics of the rumen. As NGS data continues to accumulate on ruminants fed forage, our understanding of the ruminal microbial ecosystem will grow both deeper and broader, allowing us to build predictive models of rumen function during forage degradation and fermentation.

Peripheral serotonin: An unraveled metabolite in bovines

Serotonin is an omnipotent molecule in the brain and rest of the body and plays a pivotal role in the gut-brain axis.Serotonin’s role in neurotransmission and its function at molecular levels with different genetic variants has beenwidely covered across the animal kingdom. Although the digestion process in ruminants is pillared on anaerobicmicroflora present in the rumen, the impact of the rumen microbial population on serotonergic activity is seldomexplored. Besides its principal effect on the gastrointestine, it regulates the excretion of bile acids, glucose and lipidhomeostasis, energy balance, immunomodulation, and various other vital processes in the animal system. However,the studies on part of peripheral serotonin are moderate and very few in bovines. The objective of this review is toappreciate research conducted on the basics of serotonin, triallelic polymorphism in SLR6A4 gene polymorphism,receptors and its role in GI, liver, pancreas, adipocytes, and to a little extent in other organs like uterus, mammarygland, etc. in different species and look forward to expanding the information in bovines.