scholarly journals Effects of calcium-magnesium carbonate and calcium-magnesium hydroxide as supplemental sources of magnesium on microbial fermentation in a dual-flow continuous culture

2020 ◽  
Author(s):  
J A Arce-Cordero ◽  
H F Monteiro ◽  
V L N Brandao ◽  
X Dai ◽  
S L Bennett ◽  
...  
Keyword(s):  
Magnesium Hydroxide ◽  
Magnesium Carbonate ◽  
Nutrient Digestibility ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Orthogonal Contrasts ◽  
Ruminal Ph ◽  
Molar Proportion ◽  
Calcium Magnesium ◽  
Ph Curve

Abstract Supplemental sources of Mg can also aid in ruminal pH regulation due to their alkaline properties. Magnesium oxide (MgO) is the most common source of Mg for ruminants and can help controlling ruminal pH; however, alkaline potential of other sources of Mg has not been evaluated. We aimed to evaluate the inclusion of calcium-magnesium carbonate (CaMg(CO3)2) and calcium-magnesium hydroxide (CaMg(OH)4) alone or in combination as supplemental sources of Mg in corn silage-based diets and its impact on ruminal microbial fermentation. We hypothesized that inclusion of CaMg(OH)4 would allow for ruminal fermentation conditions resulting in a greater pH compared to inclusion of CaMg(CO3)2. Four treatments were defined by the supplemental source of Mg in the diet: 1) Control (100% MgO, plus sodium sesquicarbonate as a buffer); 2) CO3 [100% CaMg(CO3)2]; 3) OH [100% CaMg(OH)4]; and 4) CO3/OH [50% Mg from CaMg(CO3)2, 50% Mg from CaMg(OH)4]. Nutrient concentration was held constant across treatments (16% CP, 30% NDF, 1.66 MCal NEl/kg, 0.67% Ca, and 0.21% Mg). Four fermenters were used in a 4x4 Latin Square design with 4 periods of 10 d each. Samples were collected for analyses of nutrient digestibility, soluble Mg, VFA, and NH3, while pH was measured at 0, 1, 2, 4, 6, 8, and 10 h post morning feeding to estimate % time when pH was below 6 (pH-B6) and area under the pH curve for pH below 6.0 (pH-AUC). Bacteria pellets were harvested for 15N analysis and estimates of N metabolism. Treatment effects were analyzed with the mixed procedure of SAS, while effects of using either CaMg(CO3)2 or CaMg(OH)4 as Mg source in comparison to Control treatment were evaluated by orthogonal contrasts. Similar pH-related variables were observed for Control, OH, and CO3/OH treatments, which had smaller pH-AUC and pH-B6 than CO3 (P ≤ 0.01). Butyrate molar proportion was greater in Control and CO3/OH than in CO3 and OH (P = 0.04). Orthogonal contrasts showed lower flow of bacterial N (P = 0.04), lower butyrate molar proportion (P = 0.08) and greater pH-AUC (P = 0.05) for diets with CaMg(CO3)2 in comparison with the Control. Concentration of soluble Mg in ruminal fluid (P = 0.73) and nutrient digestibility (P ≥ 0.52) were similar across treatments. Under the conditions of this experiment, using CaMg(OH)4 alone or combined with CaMg(CO3)2 allowed for a less acidic ruminal fermentation pattern than a diet with only CaMg(CO3)2.

scholarly journals 223 Effects of high protein DDGS in SFC or DRC-based diets on nutrient digestibility and ruminal fermentation characteristics

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 128-128
Author(s):  
Lauren Ovinge ◽  
Mitch Norman ◽  
Kaylee Wheeler ◽  
Galen E Erickson
Keyword(s):  
Latin Square ◽  
Ammonia Concentration ◽  
Nutrient Digestibility ◽  
High Protein ◽  
Starch Digestibility ◽  
Experimental Unit ◽  
Ruminal Fermentation ◽  
Dried Distillers Grains ◽  
Ruminal Ph ◽  
Treatment Design

Abstract The effect of high protein dried distillers grains plus solubles in steam flaked corn (SFC) or dry rolled corn (DRC)-based diets on rumen fermentation and nutrient digestion was evaluated. Six ruminally and duodenally cannulated heifers were utilized in a 6×6 Latin Square experiment using a 2×3 factorial treatment design. One factor was SFC or DRC-based diets, and the other factor was a control with no DGS (CON), regularly produced DDGS (DDGS), or High Protein DDGS (HiPro) included at 30% in the diet (DM basis). Data were analyzed using the MIXED procedure of SAS, with individual steer within period as the experimental unit. There was an interaction of apparent total tract starch digestibility (P 0.01), as including either DDGS or HiPro reduced starch digestibility in DRC-based diets and tended (P = 0.06) to reduce starch digestibility in SFC-based diets. Digestibility of starch was greater (P < 0.01) for SFC versus DRC-based diets across distillers treatments. Dry matter and OM apparent total tract digestibility was lowest (P < 0.01) for HiPro and DDGS was intermediate. There was no difference in molar acetate proportions (P > 0.43) between treatments. Dry rolled corn tended (P = 0.08) to have greater propionate proportion than SFC (44 vs 38%; respectively). Ammonia concentration was greater (P < 0.01) for DRC-based diets, and greatest for CON (P < 0.01) over DDGS and HiPro treatments. Average ruminal pH was unaffected by treatment (P > 0.16). Digestible energy (Mcal/kg) tended (P = 0.08) to be greater for CON over HiPro and DDGS. The use of HiPro did not affect apparent total tract nutrient digestibility as compared to DDGS in SFC or DRC-based diets. The use of either distillers product did result in a reduction in energy intake and digestibility, without affecting ruminal metabolic parameters.

scholarly journals Effects of bacterial cultures, enzymes and yeast-based feed additive combinations on ruminal fermentation in a dual-flow continuous culture system

2021 ◽  
Author(s):  
S L Bennett ◽  
J A Arce-Cordero ◽  
V L N Brandao ◽  
J R Vinyard ◽  
B C Agustinho ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Volatile Fatty Acids ◽  
Bacterial Culture ◽  
Nutrient Digestibility ◽  
Feed Additives ◽  
Feed Additive ◽  
Yeast Culture ◽  
Ruminal Fermentation ◽  
Bacterial Cultures ◽  
Molar Proportion

Abstract Bacterial cultures, enzymes and yeast derived feed additives are often included in commercial dairy rations due to their effects on ruminal fermentation. However, the effects of these additives when fed together are not well understood. The objective of this study was to evaluate the changes in ruminal fermentation when a dairy ration is supplemented with combinations of bacterial probiotics, enzymes and yeast. Our hypotheses were that ruminal fermentation would be altered, indicated through changes in volatile fatty acid profile and nutrient digestibility, with inclusion of: (1) an additive, (2) yeast and (3) increasing additive doses. Treatments were randomly assigned to 8 fermenters in a replicated 4 × 4 Latin square with four 10 d experimental periods, consisting of 7 d for diet adaptation and 3 d for sample collection. Basal diets contained 52:48 forage:concentrate and fermenters were fed 106 g of dry matter per day divided equally between 2 feeding times. Treatments were: control (CTRL, without additives); bacterial culture/enzyme blend (EB, 1.7 mg per day); bacterial culture/enzyme blend with a blend of live yeast and yeast culture (EBY, 49.76 mg per day); and double dose of the EBY treatment (2X, 99.53 mg per day). The bacterial culture/enzyme blend contained five strains of probiotics (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus lichenformis, Bacillus subtillis, and Enterococcus faecium) and three enzymes (amylase, hemicellulase, and xylanase). On d 8-10, samples were collected for pH, redox, volatile fatty acids, lactate, ammonia N and digestibility measurements. Statistical analysis was performed using the GLIMMIX procedure of SAS. Repeated measures were used for pH, redox, VFA, NH3-N and lactate kinetics data. Orthogonal contrasts were used to test the effect of: (1) additives, ADD (CTRL vs EB, EBY and 2X); (2) yeast, YEAST (EB vs EBY and 2X); and (3) dose, DOSE (EBY vs 2X). No effects (p &gt; 0.05) were observed for pH, redox, NH3-N, acetate, isobutyrate, valerate, total VFA, acetate:propionate, nutrient digestibility or N utilization. Within the 24h pool, the molar proportion of butyrate increased (p = 0.03) with the inclusion of additives when compared to the control while the molar proportion of propionate tended to decrease (p = 0.07). In conclusion, inclusion of bacterial cultures, enzymes and yeast to the diet increased butyrate concentration; but did not result in major changes in ruminal fermentation.

scholarly journals 196 Screening several phytogenic compounds for their effect on ruminal fermentation parameters in cattle fed high grain diet

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 156-157
Author(s):  
Sara Ricci ◽  
Renee M Petri ◽  
Ezequias Castillo-Lopez ◽  
Raul Rivera-Chacon ◽  
Nicole Reisinger ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Low Dose ◽  
Rumen Fluid ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Beneficial Effects ◽  
Ruminal Ph ◽  
Ruminal Acidosis ◽  
Garlic Oil ◽  
Fermentation Parameters

Abstract Phytogenic compounds, e.g. secondary plant compounds and essential oils, are often used as supplements in ruminant nutrition to modulate microbial fermentation under ruminal dysbiosis associated with high grain feeding. The aim of this study was to evaluate the short-term effects of phytogenic compounds on volatile fatty acids (VFA) production and composition in cows affected by subacute ruminal acidosis (SARA). Nine substances were tested at low and high dosage (1x and 10x respectively) using nine non-lactating ruminally cannulated Holstein cows, adapted to a 65% concentrate and 35% silage (grass and corn) ration (DM basis). Feeding was restricted for nine hours before providing the substance mixed with five kg of TMR. Each substance and dosage was tested individually on four cows (n = 4/compound/dose) over a period of four hours. Rumen and reticulum fluid were collected before the treatment, and four hours after feeding. VFA were measured with gas chromatography. Ruminal pH was continuously recorded (eCow indwelling pH systems). Data were analyzed with the Proc Mixed procedure of SAS. Seven out of nine compounds showed an effect or a trend on VFA measured, both in rumen and reticulum. Acetic acid in rumen fluid decreased with garlic oil, while low dose mint oil increased its concentration (P = 0.06 and P = 0.01, respectively). Low dose mint oil (P &lt; 0.01) and L-menthol (P = 0.03) both increased the A:P ratio, whereas garlic oil tended towards a decrease in the A:P ratio. Garlic oil and ginger showed negative correlations between total VFA and mean ruminal pH (P = 0.03 and P &lt; 0.01, respectively). Our results suggest that phytogenic compounds can modulate microbial activity within four hours of feeding. The use of phytogenic compounds may have beneficial effects on microbial fermentation under low pH conditions associated with high grain feeding.

scholarly journals Effect of rye grain derived from different cultivars or maize grain use in the diet on ruminal fermentation parameters and nutrient digestibility in sheep

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Patrycja Rajtar ◽  
Paweł Górka ◽  
Bogdan Śliwiński ◽  
Jarosław Wieczorek ◽  
Danuta Boros ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Short Chain Fatty Acids ◽  
Nutrient Digestibility ◽  
Short Chain ◽  
Ruminal Fermentation ◽  
Ruminal Ph ◽  
Nutrient Digestion ◽  
Maize Grain ◽  
Fermentation Parameters ◽  
Hybrid Cultivar

AbstractSix wether sheep with ruminal and duodenal cannulas were used in a replicated 3 × 3 Latin square to determine the effect of rye grain (from an open-pollinated or a hybrid cultivar) and maize grain from hybrid cultivar inclusion in the diet on ruminal fermentation parameters and nutrient digestion in different gastrointestinal tract compartments. The experimental diets consisted of meadow hay (800 g/day) and a concentrate mixture (300 g/day) that contained rye grain from an open-pollinated cultivar (OPRG), rye grain from a hybrid cultivar (HRG), or maize grain from a hybrid cultivar (MG) as a main energy source. Each experimental period lasted 17 days and consisted of 10 days for diet adaptation and 7 days for data and sample collection. Ruminal fermentation (pH, short-chain fatty acids, and ammonia concentration) and nutrient digestion up to the duodenum (in reticulorumen, omasum, and abomasum), in the intestine, as well as in the total digestive tract was investigated. Mean ruminal pH was higher for MG compared to HRG and OPRG (P<0.01) but did not differ between HRG and OPRG (6.45, 6.35, and 6.29 for MG, HRG, and OPRG, respectively). Treatment did not affect short-chain fatty acid concentration in the rumen, except for the molar proportions of valeric acid and of isovaleric acid of the total short-chain fatty acids, which was or tended to be higher (P≤0.06) for MG compared to HRG and OPRG. Less starch was digested in the gastrointestinal tract up to the duodenum and more in the intestine for MG compared to HRG and OPRG (P=0.01); however, total tract nutrient digestibility did not differ between treatments. In conclusion, usage of rye grain in sheep diets resulted in a lower ruminal pH compared to maize grain usage. No differences for ruminal fermentation, nutrient digestion up to the duodenum, in the intestine, as well as in the total digestive tract between rye grain from open-pollinated and hybrid cultivar usage in sheep diets were found.

scholarly journals Apparent total tract digestibility, ruminal fermentation, and blood metabolites in beef steers fed green-chopped cool-season forages

2020 ◽  
Vol 98 (6) ◽  
Author(s):  
Tessa M Schulmeister ◽  
Martin Ruiz-Moreno ◽  
Mariana E Garcia-Ascolani ◽  
Francine M Ciriaco ◽  
Darren D Henry ◽  
...  
Keyword(s):  
Lolium Multiflorum ◽  
Nutrient Digestibility ◽  
Neutral Detergent Fiber ◽  
Blood Metabolites ◽  
Beef Steers ◽  
Annual Ryegrass ◽  
Ruminal Fermentation ◽  
Cool Season ◽  
Plasma Urea ◽  
Ruminal Ph

Abstract An experiment was conducted during the winter of two consecutive years to evaluate the effects of feeding green-chopped cool-season forages on digestibility, ruminal fermentation, and blood parameters in beef steers. Nine ruminally cannulated Angus crossbred steers (year 1: 359 ± 79 kg; year 2: 481 ± 105 kg) received ad libitum green-chopped forages from pastures planted with one of the following mixtures: 1) OAT = Horizon 201 oats (Avena sativa L.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 95 and 17 kg/ha, respectively; 2) RYE = FL401 cereal rye (Secale cereale L.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 78 and 17 kg/ha, respectively; or 3) TRIT = Trical 342 triticale (X Triticosecale spp.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 95 and 17 kg/ha, respectively. Intake was measured using the GrowSafe system and orts were discarded prior to subsequent feeding. After a 14-d adaptation, feed and fecal samples were collected twice daily for 4 d to determine apparent total tract nutrient digestibility using indigestible neutral detergent fiber (NDF) as an internal marker. On day 19, blood and ruminal fluid samples were collected every 3 h during a 24-h period to analyze plasma urea nitrogen (PUN) and glucose, ruminal pH, and concentration of ruminal ammonia nitrogen (NH3-N) and volatile fatty acids (VFA). Data were analyzed as a generalized randomized block design with repeated measures using the PROC MIX of SAS. No effect of treatment (P &gt; 0.05) was observed for intake of dry matter, organic matter (OM), crude protein, NDF, or acid detergent fiber. Apparent total tract digestibility of nutrients was greater (P &lt; 0.05) for OAT and TRIT when compared with RYE, with OM digestibility being 82.7%, 79.6%, and 69.5%, respectively. An effect of time (P &lt; 0.01) was observed for ruminal pH. Plasma concentration of glucose was greater (P &lt; 0.01) in steers consuming OAT, whereas steers fed RYE had greater (P &lt; 0.05) concentrations of ruminal NH3-N and PUN, and the least concentration of total ruminal VFA (P &lt; 0.05), despite having the greatest (P &gt; 0.05) molar proportion of acetate, branched-chain VFA, and acetate:propionate. Increased nutrient digestibility and favorable ruminal fermentation and blood metabolites of OAT and TRIT are potentially conducive to enhanced growth performance when compared with RYE.

Furanocoumarins in tedera do not affect ruminal fermentation in continuous culture

2015 ◽  
Vol 55 (4) ◽  
pp. 544 ◽  
Author(s):  
M. H. Ghaffari ◽  
Z. Durmic ◽  
D. Real ◽  
P. Vercoe ◽  
G. Smith ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Protein Digestibility ◽  
Nutrient Digestibility ◽  
In Vitro Digestibility ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Fermentation Liquid ◽  
Acid Detergent Fibre ◽  
Sampling Times

The objective of this study was to investigate the effects of the forage shrub tedera (Bituminaria bituminosa) on nutrient digestibility, rumen microbial fermentation and furanocoumarins degradation in the rusitec. The variables were measured in fermentation liquid on Days 13 and 17 and were compared with a control (lucerne hay). Overall, tedera had greater (P < 0.05) neutral detergent fibre and acid detergent fibre digestibility than lucerne hay on both days of the experiment, but on Day 17 it had lower (P < 0.01) dry matter and crude protein digestibility than lucerne hay. There were no significant differences in concentration of NH3-N and pH between treatments, but NH3-N concentrations in both treatments were lower (P < 0.05) on Day 17 than on Day 13. The concentration of total volatile fatty acids in vessels were not affected by treatments, but the concentration of acetate was lower and acetate-to-propionate ratio higher (P < 0.05) in tedera than lucerne hay on Day 13 of the experiment. Furanocoumarins were detected in the tedera treatment only. Their concentration in the fermentation liquid increased immediately after the addition of the plant material to the fermenter, reaching highest concentrations after 2 h. These concentrations gradually declined over the next two sampling times, but 6 h after the ‘feeding’, they were still detectable in the fermentation liquid. It was concluded that (i) tedera had in vitro digestibility and fermentability variables comparable to lucerne; (ii) furanocoumarins were degraded in the fermentation fluid, and (iii) furanocoumarins from tedera did not seem to impede microbial fermentation. Tedera may provide an alternative feed source to hay and grain for filling the summer–autumn feed gap without negatively affecting nutrient digestibility and rumen microbial fermentation.

Improving ruminal fermentation and nutrient digestibility in dairy steers by banana flower powder-pellet supplementation

2018 ◽  
Vol 58 (7) ◽  
pp. 1246 ◽  
Author(s):  
Sungchhang Kang ◽  
Metha Wanapat
Keyword(s):  
Feed Intake ◽  
Latin Square ◽  
Bacterial Count ◽  
Nutrient Digestibility ◽  
Control Group ◽  
Ruminal Fermentation ◽  
Ruminal Ph ◽  
Rumen Ecology ◽  
Microorganism Population ◽  
Banana Flower

The present study aimed to investigate the effect of banana flower powder pellet (BAFLOP pellet) on nutrient digestibility, rumen ecology and microorganism population. Four rumen-fistulated dairy steers of 200 ± 20 kg bodyweight were randomly assigned to receive four dietary treatments according to a 4 × 4 Latin square design. The treatments were as follows: control (T1), NaHCO3 supplementation at 20 g/kg of total dry-matter feed intake (DMI; T2), BAFLOP-pellet supplementation at 20 g/kg of DMI (T3) and BAFLOP-pellet supplementation at 40 g/kg of DMI (T4). All cattle were fed roughage–concentrate mix (30 : 70 ratio) at 25 g/kg bodyweight. Standard management protocols were employed during the experimental periods. The results showed that nutrient digestibility was increased in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI (P < 0.05). Although ruminal temperature and blood urea nitrogen were not influenced by dietary supplementation, ruminal pH was increased (P < 0.05) in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI. In addition, NaHCO3 supplementation increased bacterial and protozoal populations, whereas populations of fungal zoospores were similar among treatments. Supplementation with BAFLOP pellets at 40 g/kg DMI increased the bacterial count, whereas protozoal numbers were similar to those in the control group (P < 0.05). On the basis of the present findings, BAFLOP-pellet supplementation improved nutrient digestibility, ruminal pH and microbial population, without having any adverse effects on voluntary feed intake. The present study showed promising results for BAFLOP pellets (40 g/kg DMI) as a rumen dietary buffering agent, suggesting that these pellets could be used a replacement for sodium bicarbonate in ruminants fed high-concentrate diets.

Effects of fibre level and particle size on rumen microbial fermentation and protein metabolism using liquid and solid associated bacteria

2001 ◽  
Vol 2001 ◽  
pp. 149-149
Author(s):  
M. Rodríguez ◽  
S. Calsamiglia ◽  
A. Ferret
Keyword(s):  
Particle Size ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Associated Bacteria ◽  
Dietary Nitrogen ◽  
Ruminal Ph ◽  
Fermentation Profile ◽  
N Metabolism

The effects of fibre level (F) and forage particle size (S) on ruminal fermentation profile is often mediated through changes in feed intake, rates of digestion or passage, ruminal pH and/or bacteria population. Therefore, most in vivo studies have confounded the direct effect of F or S with changes in the rumen environment. In vitro systems allow to control several fermentation conditions independently (pH, flow rates, intake). Total, bacterial and dietary nitrogen (N) flows are generally calculated using liquid associated bacteria (LAB), although solid associated bacteria (SAB) represent about 80% of total bacterial population in the rumen (Olobobokun and Craig, 1988). The objective of this experiment was to study the effects of F and S on microbial fermentation and N metabolism using LAB or SAB values in a dual flow continuos culture system.

Influence of grain and monensin supplementation on ruminal fermentation, intake, digesta kinetics and incidence and severity of frothy bloat in steers grazing winter wheat pastures

1990 ◽  
Vol 68 (4) ◽  
pp. 1139-1150 ◽  
Author(s):  
M. E. Branine ◽  
M. L. Galyean
Keyword(s):  
Winter Wheat ◽  
Beef Steers ◽  
Ruminal Fermentation ◽  
Passage Rate ◽  
Ruminal Ph ◽  
Molar Proportion ◽  
Wheat Pasture ◽  
Forage Intake

Abstract Three 10-d collection periods (April 4 to 14, early April, EApr; April 23 to May 3, late April, LApr; May 10 to 20, 1984, mid-May, MMay) were conducted to evaluate effects of no supplement (C), .5 kg·head−1·d−1 (as-fed basis) supplemental grain (steam-flaked milo, G) or G plus 170 mg monensin·headhead−1·d−1 (M) on forage intake and digestion by 12 ruminally cannulated beef steers (four/treatment; avg initially BW = 393 kg) grazing irrigated winter wheat pasture. Ruminal pH was greater (P < .01) for M than for C or G during EApr but was not altered by treatments in LApr or MMay. Compared with C, ruminal NH3 was decreased (P < .10) by G and M (5 h after supplementation) in EApr, decreased (P < .05) by G (2h) and increased (P < .05) by M (8 h) in LApr and decreased (P < .10) by G (−1h) in MMay. Treatments had little influence on total VFA concentrations or on molar proportions of acetate and propionate. Butyrate molar proportion was decreased (P < .10) by M during EApr and LApr, but not during MMay. Monensin increased (P < .05) fluid passage rate compared with C and G in EApr but not in other periods. Particulate passage measurements did not differ (P > .10) among treatments within periods. Forage DM intake was not influenced (P > .10) by supplementation during any period. Extent of in situ forage DM disappearance was greater (P < .10) for M than for C or G during EApr (12 and 30 h of incubation) but was not different (P > .10) in LApr or MMay. Incidence of frothy bloat was decreased (P < .05) by M during EApr; this reduction may have been related to effects of M on ruminal pH, forage digestion and fluid passage.

Effects of essential oils and their components on in vitro rumen microbial fermentation

2007 ◽  
Vol 87 (3) ◽  
pp. 413-419 ◽  
Author(s):  
C. Benchaar ◽  
A. V. Chaves ◽  
G. R. Fraser ◽  
K. A. Beauchemin ◽  
T. A. McAllister
Keyword(s):  
Essential Oil ◽  
Dairy Cattle ◽  
Essential Oils ◽  
Batch Culture ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Neutral Detergent Fibre ◽  
Molar Proportion ◽  
Leaf Oil

The objective of this study was to investigate the effects of essential oils (EO) and essential oil compounds (EOC) on in vitro rumen microbial fermentation. Treatments were: control (no additive), cinnamon leaf oil (400 mg L-1), clove leaf oil (200 mg L-1), sweet orange oil (200 mg L-1), oregano oil (200 mg L-1), thyme oil (200 mg L-1), carvacrol (400 mg L-1), cinnamaldehyde (400 mg L-1), eugenol (800 mg L-1), and thymol (400 mg L-1). Treatments were evaluated using in vitro 24-h batch culture of rumen fluid with a 51:49 forage:concentrate dairy ration [16.7% crude protein (CP), 34.4% neutral detergent fibre (NDF)]. Incubations were conducted in triplicate with gas production (GP) measured at 0, 2, 6, 8, 12, and 24 h, while pH, ammonia (NH3), volatile fatty acid (VFA), in vitro dry matter (IVDMD) and neutral detergent fibre (IVNDFD) digestibilities were determined after 24 h of incubation. Among the EO and EOC evaluated, only the phenolic compounds, carvacrol, thymol, and eugenol affected ruminal fermentation, relative to the control. Carvacrol (400 mg L-1) and eugenol (800 mg L-1) increased pH and molar proportion of butyrate, and decreased molar proportion of propionate, IVDMD, IVNDFD, and GP. At the concentration of 200 mg L-1, thymol increased final pH, a nd reduced molar proportion of propionate, IVNDFD, and GP. None of the EO or EOC affected NH3 concentration, suggesting that at the doses tested in this study, protein degradation was not affected by EO and EOC. This study showed that among the EO and EOC investigated only phenolics exhibited antimicrobial activity as exemplified by reduced diet fermentability and a shift in VFA profile from less propionate towards more butyrate. These changes in fermentation may not be nutritionally beneficial to dairy cattle. The present study suggests that the types and concentrations of EO and EOC employed to alter ruminal fermentation must be carefully defined before their widespread use in ruminant nutrition can be recommended. Key words: Essential oil, ruminal fermentation, in vitro batch culture, dairy cattle

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