Concentrations Of Individual Volatile Fatty Acids Research Articles

The Effect of Humic Acid Supplementation on Selected Ruminal Fermentation Parameters and Protozoal Generic Distribution in Cows

The objective of this study was to examine the effect of humic acid (HA) supplementation on the rumen fermentation and protozoal community in the rumen. For this purpose, four ruminally cannulated Simmental cows were randomly assigned in a replicated 4 × 4 Latin square design experiment to study the effect of HA dietary supplementation on feed utilization, rumen fermentation, and protozoal community for 84 days. The basal diet (BD) was composed of meadow hay (68.2% of dry matter [DM]), maize silage (17% of DM), and granulated feed mixture (14.9% of DM). There were four treatments, including the BD without additives (control diet, H0), the BD supplemented with 50 g HA/cow/day (H50 treatment), the BD supplemented with 100 g HA/cow/day (H100 treatment), and the BD supplemented with 200 g HA/cow/day (H200 treatment). HA supplementation did not affect the total or individual volatile fatty acid concentrations, the total protozoa, or the ruminal pH. However, HA at the dosage of 50 g/cow/day increased the NH3-N concentration and fecal nitrogen compared to the control (p < 0.001). HA supplementation also significantly impacted the abundance of individual protozoal genera in the rumen. The results of this study suggest that HA has potential in ruminants as a natural feed additive and may play a role in nitrogen metabolism and stabilizing the protozoal community without adverse effects on rumen fermentation.

Acid-base properties of non-protein nitrogen affect nutrients intake, rumen fermentation and antioxidant capacity of fattening Hu sheep.

This study conducted a comparison of the effects of non-protein nitrogen with different acid-base properties on feed intake, rumen fermentation, nutrient digestion and antioxidant capacity in fattening Hu sheep. Sixteen fattening male sheep (31.43 ± 2.41 kg) with permanent rumen cannulas were randomly assigned to two dietary treatments: 1% urea and 1.78% ammonium chloride (NH4Cl, AC). A 42 days experimental period was conducted, with 14 days for adaptation and 28 days for treatment. Daily feed intake was recorded and various samples including feed, feces, rumen fluid, and blood were collected at different time points during the final week. The results indicated that the urea group had significantly higher dry matter intake, average daily gain, and gain efficiency in comparison to the AC group (p < 0.01). There was no difference in rumen pH and concentration of ammonia nitrogen between different groups (p > 0.05), but the rumen pH of urea group was higher than that of the AC group at 1 and 3 h after feeding (p < 0.05). The urea group exhibited higher concentrations of total volatile fatty acids (VFA) and individual VFAs compared to the AC group at all-time points (p < 0.01). Compared to the urea group, the intake of all nutrients decreased in the AC group (p < 0.01), but the digestibility of dry matter and organic matter increased significantly (p < 0.01), and the digestibility of CP had an increasing trend (p = 0.06) in the AC group. Additionally, the urea group had lower levels of serum glucagon-like peptide-1, peptide YY, Cl, total protein and globulin than the AC group (p < 0.05). The overall levels of HCO3-, superoxide dismutase, glutathione peroxidase, catalase, albumin/globulin, blood urea nitrogen and total cholesterol in the urea group increased significantly compared to the AC group (p < 0.05). It was concluded that adding urea to the high-concentrate diet resulted in increased rumen pH and improved rumen fermentation and growth performance in fattening sheep compared to NH4Cl addition. Furthermore, urea addition improved sheep's antioxidant capacity and maintained their acid-base balance more effectively as compared to NH4Cl.

Essential Oil Blends with or without Fumaric Acid Influenced In Vitro Rumen Fermentation, Greenhouse Gas Emission, and Volatile Fatty Acids Production of a Total Mixed Ration

The growing interest in improving rumen fermentation and mitigating methane emissions necessitates the use of essential oil blends (EOB) and fumaric acid (FA). This study evaluated the synergistic effect of four EOB with or without FA supplementation on in vitro dry matter digestibility, greenhouse gas emission, and total volatile fatty acid production using inoculum from three rumen-cannulated Black Angus beef cows. The study was arranged in a 4 × 2 + 1 factorial design to evaluate the effects of the four EOB and two FA levels on a total mixed ration (TMR). The EOB dosage was 100 µL while FA was added at 3% of total mixed ration. The EOB × FA interaction (p &lt; 0.05) influenced the dry matter, neutral detergent fiber, and hemicellulose degradabilities. All the EOB and FA (EFA) treatments decreased (p &lt; 0.001) the dry matter degradability compared to the control (TMR substrate only). The EFA4 treatment reduced the neutral detergent fiber and hemicellulose degradabilities compared to the control. The ruminal pH was influenced (p &lt; 0.001) by both the EOB and FA inclusion, and the EOB × FA interaction was significant. The microbial mass was higher (p &lt; 0.001) in the EFA1, EFA4, and EOB4 compared to the control and the EOB3 treatments. The EFA1 and EOB1 produced less (p &lt; 0.001) gas than the control by 29.1 and 32.1%, respectively. Compared with the control, the EFA1 and EOB1 treatments decreased (p &lt; 0.001) methane gas by 90.8% and 86.4%, respectively, while the carbon dioxide was reduced (p = 0.004) by 65.7 and 57.9%, respectively. The EOB × FA interaction was significant (p &lt; 0.001) for the total and individual volatile fatty acid concentrations. The inclusion of FA increased the propionate concentration by 9.5% and decreased (p = 0.02) the acetate concentration by 4%. In summary, the synergistic effect of the EOB and FA offers an effective way to reduce greenhouse gas emission and enhance total volatile fatty acids.

Capric and lauric acid mixture decreased rumen methane production, while combination with nitrate had no further benefit in methane reduction

Abstract This study aimed to evaluate the methane-reducing potential of individual and combined treatments of low levels of nitrate (NIT) and a mixture of capric/lauric acid (CL) in dairy cows. Both in vitro and in vivo experiments were conducted. In the in vitro experiment, the anti-methanogenic effects of NIT (1.825 mmol/l) and CL (250 mg/l; capric acid, 125 mg/l + lauric acid, 125 mg/l) were evaluated in a 2 × 2 factorial design using consecutive batch incubations with rumen fluid. The NIT and CL reduced (P&lt;0.05) methane production by 9.2% and by 21.3%, respectively. However, combining NIT with CL did not show (P&gt;0.05) any benefit in methane reduction compared to the use of CL alone. In the in vivo experiment, eight multiparous dry Holstein cows were fed two diets in a crossover design for two 21-day periods (14 days of adaptation and 7 days of sampling). The treatments were: 1) silage-based basal diet + 100 g stearic acid per cow/d (CON) and 2) silage-based basal diet + 50 g capric acid + 50 g lauric acid per cow/d (CL). Gas emissions were measured using open-circuit respiration chambers. Methane production (g/d) was reduced (by 11.5%; P = 0.012) when the diet was supplemented with CL. However, supplementation with CL increased ruminal ammonia-N concentration (by 28.5%; P = 0.015) and gas ammonia production (g/d; by 37.2%; P = 0.005). Ruminal pH, protozoa count, and total and individual volatile fatty acid concentrations (VFA ) did not differ (P&gt;0.05) between the treatments. Treatment did not affect the intake and apparent total tract digestibility (P&gt;0.05). In conclusion, our results suggest that low CL levels have anti-methanogenic potential. However, low levels of CL may compromise nitrogen use efficiency.

Characterizing ruminal acidosis risk: A multiherd, multicountry study

A multicenter observational study was conducted on early lactation Holstein cows (n = 261) from 32 herds from 3 regions (Australia, AU; California, CA; and Canada, CAN) to characterize their risk of acidosis into 3 groups (high, medium, or low) using a discriminant analysis model previously developed. Diets ranged from pasture supplemented with concentrates to total mixed ration (nonfiber carbohydrates = 17 to 47 and neutral detergent fiber = 27 to 58% of dry matter). Rumen fluid samples were collected <3 h after feeding and analyzed for pH, and ammonia, d- and l-lactate, and volatile fatty acid (VFA) concentrations. Eigenvectors were produced using cluster and discriminant analysis from a combination of rumen pH, and ammonia, d-lactate, and individual VFA concentrations and were used to calculate the probability of the risk of ruminal acidosis based on proximity to the centroid of 3 clusters. Bacterial 16S ribosomal DNA sequence data were analyzed to characterize bacteria. Individual cow milk volume, fat, protein, and somatic cell count values were obtained from the closest herd test to the rumen sampling date (median = 1 d before rumen sampling). Mixed model analyses were performed on the markers of rumen fermentation, production characteristics, and the probability of acidosis. A total of 26.1% of the cows were classified as high risk for acidosis, 26.8% as medium risk, and 47.1% as low risk. Acidosis risk differed among regions with AU (37.2%) and CA (39.2%) having similar prevalence of high-risk cows and CAN only 5.2%. The high-risk group had rumen phyla, fermentation, and production characteristics consistent with a model of acidosis that reflected a rapid rate of carbohydrate fermentation. Namely, acetate to propionate ratio (1.98 ± 0.11), concentrations of valerate (2.93 ± 0.14 mM), milk fat to protein ratio (1.11 ± 0.047), and a positive association with abundance of phylum Firmicutes. The medium-risk group contains cows that may be inappetant or that had not eaten recently or were in recovery from acidosis. The low-risk group may represent cattle that are well fed with a stable rumen and a slower rumen fermentation of carbohydrates. The high risk for acidosis group had lower diversity of bacteria than the other groups, whereas CAN had a greater diversity than AU and CA. Rumen fermentation profile, abundance of ruminal bacterial phyla, and production characteristics of early lactation dairy cattle from 3 regions were successfully categorized in 3 different acidosis risk states, with characteristics differing between acidosis risk groups. The prevalence of acidosis risk also differed between regions.

Dietary inclusion of anthocyanin-rich black cane silage treated with ferrous sulfate heptahydrate reduces oxidative stress and promotes tender meat production in goats.

Pre-treating anthocyanin-rich black cane with ferrous sulfate heptahydrate (FSH) produces high-quality silage with anthocyanin and nutritional losses. However, it's unclear how to apply this to studies on how FSH-treated silage affects animal performance and meat quality. Therefore, this study aimed to investigate the effects of a standard total mixed ration (TMR) containing anthocyanin-rich black cane silages either with or without dilutions of FSH on animal performance, blood biochemical indices, rumen fermentation, microbial community, and carcass characteristics in meat goats. Forty healthy crossbred Thai-native Anglo-Nubian male goats (14.42 ± 1.4 kg) were used to compare the feasibility of using anthocyanin-rich black cane silage (ABS) as a functional feed resource as opposed to anthocyanin-rich black cane treated with 0.030% commercial FSH silage (ABSF). All goats received a 90-day routine feeding of two isocaloric and isonitrogenous experimental diets: the control group received TMR containing 50% anthocyanin-rich black cane silage (ABS; n = 20), and one group received TMR containing 50% FSH-treating anthocyanin-rich black cane (ABSF; n = 20). As performance indicators, average daily weight gain (ADG) and dry matter intake (DMI) were measured. Samples of meat, blood, and rumen were taken at the end of the experiment. There were no differences in final body weight, ADG, DMI, or ADG/DMI between the two groups. The ABSF group did not differ from the ABS group in terms of rumen pH, but the ABSF had a tendency to lower rumen ammonia N levels, and to higher total volatile fatty acid (VFA) concentrations. Individual VFA concentrations differed, with the ABSF group having more Ruminococcus albus and the ABS group having more methanogenic bacteria. Blood biochemical indices differed, with the ABSF group having lower TBARS concentrations and the ABS group having lower TAC, SOD, CAT, GSH-Px, and GSH-Rx concentrations. In comparison to goat meat from the ABS group, goat meat from the ABSF group contained more intramuscular fat and was more tender. The current results indicate that the feeding of a TMR containing 50% anthocyanin-rich black cane, along with FSH pre-treatment prior to ensiling, reduces oxidative stress and promotes the production of tender meat without affecting animal performance.

Growth Performance, Blood Biochemical Indices, Rumen Bacterial Community, and Carcass Characteristics in Goats Fed Anthocyanin-Rich Black Cane Silage.

The goal of this study was to investigate the effects of a standard total mixed ration (TMR) with containing anthocyanin-rich plants on animal performance, blood biochemical indices, rumen fermentation, microbial composition, and carcass characteristics in meat goats. Thirty-six healthy crossbred Thai-native Anglo-Nubian male goats (14.42 ± 0.6 kg) were used to compare the possibility of using anthocyanin-rich black cane silage (AS) in place of Napier grass silage (NS) as a functional feed resource. All goats received a 90-d routine feeding consisting of two experimental diets that were isocaloric and isonitrogenous: the control group received TMR containing 50% NS (NS; n = 18), and one group received TMR containing 50% AS (AS; n = 18). Average daily weight gain (ADG) and dry matter intake (DMI) were measured as indicators of performance. At the end of the experiment, meat, blood, and rumen samples were collected. There were no differences between the two groups in terms of final body weight, ADG, DMI, or ADG/DMI. There were no differences in rumen pH or total volatile fatty acids (VFAs); however, rumen ammonia N concentrations were lower in the AS group than in the NS group. Individual VFA concentrations varied, with AS group containing more Ruminococcus albus and NS group containing more methanogenic bacteria. Blood biochemical indices varied, with NS group having higher TBARS concentration and AS group having higher concentrations of TAC, SOD, CAT, GSH-Px, and GSH-Rx. Goat meat from the AS group had higher levels of intramuscular fat and was more tender compared to goat meat from the NS group. The feeding of anthocyanin-rich black cane appears to be an attractive alternative for Napier grass in the nutrition of meat goats. The current results indicate that the feeding of a TMR containing 50% anthocyanin-rich black cane alleviates oxidative stress and promotes the production of tender meat.

Effects of age and supplemental xylanase in corn- and wheat-based diets on cecal volatile fatty acid concentrations of broilers

An experiment was conducted to evaluate the effects of age and supplemental xylanase in corn- or wheat-based diets on cecal volatile fatty acid (VFA) concentrations of Ross × Ross 708 male broilers during weekly intervals from 14 to 42d of age. Day-old chicks (1,500) were randomly distributed into 60 floor pens (25 chicks/pen; 0.078 m2/bird) and fed 1 of 4 dietary treatments (TRT) throughout the starter (1 to 14d of age), grower (15 to 28d of age), and finisher (29 to 42d of age) phases with 15 replicates per TRT. Dietary TRT consisted of a 2 × 2 factorial arrangement with 2 diet types (corn- or wheat-based) and 2 xylanase inclusions (0 or 16,000 BXU/kg) as the main factors. At 14, 21, 28, 35, and 42d of age, cecal contents were collected (4 birds/pen) for VFA analysis. Main effects of cereal grain source (P < 0.05) affected propionic, isobutyric, butyric, isovaleric, valeric, and isocaproic acid concentrations at 14, 21, 28, 35, and 42d of age. Broilers fed corn-based diets had higher (P < 0.05) propionic, isobutyric, isovaleric, valeric, and isocaproic concentrations than those fed wheat-based diets from 14 to 42d of age. However, broilers fed wheat-based diets had higher (P < 0.05) butyric acid concentrations at 28, 35, and 42d of age compared with those fed corn-based diets. Individual and total VFA concentrations increased (P < 0.05) linearly from 14 to 42d of age. Age and cereal grain interacted (P < 0.05) to affect propionic, isobutyric, butyric, isovaleric, and valeric acid concentrations. These results indicate that broiler cecal VFA concentrations are influenced by cereal grain source and age. In contrast, supplemental xylanase inconsistently influenced broiler cecal VFA concentrations. Therefore, future research evaluating factors affecting supplemental xylanase and cecal VFA production in broilers is warranted. Additionally, research investigating cereal grain source effects on cecal microflora development and fermentative patterns may be beneficial for optimizing cecal VFA production in broilers.

Effects of cereal grain source and supplemental xylanase concentrations on broiler growth performance and cecal volatile fatty acid concentrations from 1 to 40 d of age

An experiment was conducted to evaluate the effects of feeding diets varying in cereal grain source and supplemental xylanase concentrations on growth performance and cecal volatile fatty acid (VFA) concentrations of Ross × Ross 708 male broilers from 1 to 40d of age. A total of 1,536 day-old chicks were randomly distributed into 64 floor pens (24 chicks/pen; 0.08 m2/bird) and fed 1 of 8 dietary treatments (TRT) with 8 replicates per TRT. Experimental TRT were of either corn- (TRT 1 to 4) or wheat-based (TRT 5 to 8) origins. The 4 dietary TRT for each cereal grain source consisted of a positive control (PC) reference diet and 3 reduced AMEn diets (AMEn reduced 66kcal/kg below PC) with supplemental xylanase at either 0 (negative control), 12,000, or 24,000 BXU/kg. Birds and feed were weighed at 1, 14, 26, and 40d of age to determine BW gain, feed intake, and feed conversion ratio. At 26 and 40d of age, cecal contents were collected and pooled per pen (7 birds/pen; 5 replicate pens/TRT) for VFA concentrations. No TRT differences (P > 0.05) in cumulative growth performance were observed. Likewise, no TRT differences (P > 0.05) in acetic or total VFA concentrations were observed at 26 or 40d of age. However, cereal grain source (P < 0.05) influenced propionic, isobutyric, butyric, and isovaleric concentrations at 26 and 40d of age with birds receiving the corn-based diets having higher (P < 0.05) cecal propionic, isobutyric, and isovaleric concentrations, and lower (P < 0.05) butyric acid concentrations than those fed the wheat-based diets. These results indicate that dietary cereal grain source may influence individual cecal VFA concentrations. However, supplemental xylanase did not affect broiler growth performance or cecal VFA concentrations. Therefore, future research evaluating factors limiting xylanase responses on broiler growth performance and cecal VFA production is warranted.

349 Relationship between ruminal volatile fatty acids and microbial population with carcass and meat quality traits in beef steers.

Volatile fatty acids (VFAs), the end products of rumen fermentation, are the principal energy source for ruminants which potentially affect carcass yield and fat deposition in beef cattle. Rumen microbiota affects lipid metabolism in ruminants which might contribute to the variation in fat deposition. In this study, rumen fluid samples were collected from 204 beef steers raised under feedlot in Roy Berg Kinsella Research Ranch, University of Alberta. Individual VFA concentrations were measured using gas chromatography, and the bacterial and archaeal abundances were estimated by measuring total copy numbers of their respective 16S rRNA genes using qPCR. Animal phenotypic measures including body weight (BW), dry matter intake (DMI), average daily gain (ADG), hot carcass weight (HCW), age at slaughter (age), ribeye area (CREA), adipose fat thickness (AFAT), lean meat yield (LMY) and marbling score (MS) were collected. The relationships among microbiota, VFAs and carcass traits were evaluated using stepwise, backward linear regression with a significant level of 0.05. The HCW was positively correlated with BW and ADG and was negatively correlated with propionate. Negative correlations were identified between age and BW, RFI, acetate, propionate, and butyrate. CREA had positive correlations with BW and DMI, and negative correlations with acetate. AFAT was positively correlated with DMI, BW and propionate while, acetate and butyrate tentatively positively correlated (P < 0.1) with AFAT. The LMY was negatively correlated with BW, DMI, acetate, propionate and butyrate. Marbling score was positively correlated with DMI, acetate, propionate and butyrate. The relationship between rumen microbial abundance and the above carcass and meat quality-related traits were not detected in this study. Our preliminary results reveal that rumen VFAs may contribute to carcass and meat quality traits in beef cattle, suggesting the potential application to improving carcass and meat quality in beef steers through manipulating rumen VFA.

Effect of Individual Components of Lignocellulosic Biomass on Methane Production and Methanogen Community Structure

One of the major factors that influences the economic feasibility of biogas production is the availability of digestible feedstocks. There is little research on the influence of the chemical composition of biomass on biogas synthesis, especially with regard to the content of lignocellulosic materials. Therefore, the aim of this study was to estimate how differences in the content of cellulose and lignin in lignocellulosic biomass influence the concentrations of individual volatile fatty acids (VFAs) and biogas production. Additionally, the structure of the methanogenic community was examined. The removal of fibrous and non-fibrous materials, the concentrations of individual VFAs, methane production and methanogen community structure were examined during digestion of Zea mays L. and Miscanthus sacchariflorus silages. Organics were removed with higher efficiency during the digestion of Z. mays silage than during digestion of M. sacchariflorus. This was due to the higher non-fibrous carbohydrates content in Z. mays than in M. sacchariflorus. In both digesters, propionate predominated throughout experiment. The methanogenic community in the digester fed with Z. mays was more diverse than that in the digester with M. sacchariflorus. Analysis of 16S rRNA sequences showed that six acetoclastic and four hydrogenotrophic methanogens were present in the digester fed with Z. mays L., while five acetoclastic and three hydrogenotrophic methanogens were in the digester fed with M. sacchariflorus. The abundance of Methanosarcina correlated significantly with the concentration of all analyzed VFAs.

Effect of dietary nitrate on enteric methane emissions, production performance and rumen fermentation of dairy cows grazing kikuyu-dominant pasture during summer

Dietary nitrate supplementation is an effective methane (CH4) mitigation strategy in total mixed ration based diets fed to ruminants. To date, limited information is available on the effect of dietary nitrate on CH4 production from grazing dairy cows. Fifty-four multiparous Jersey cows were subjected to a randomised complete block design (blocked according to milk yield, days in milk and parity) to evaluate the effect of three dietary nitrate levels on enteric CH4 emissions and cow production performance. Additionally, six rumen-cannulated cows in a replicated 3 × 3 Latin square design were used in a rumen study. Dietary treatments consisted of concentrate fed at 5.4 kg of DM/cow per day containing one of three levels of dietary nitrate: 0 g (control), 11 g (low nitrate), and 23 g of nitrate/kg of dry matter (DM; high nitrate). Cows grazed late-summer pasture containing approximately 3 g of nitrate/kg of DM. Concentrates were formulated to be isonitrogenous, by substituting urea, and isoenergetic. Cows were gradually adapted to concentrates over a 3-wk period before the onset of a 57-d experimental period. Enteric CH4 emissions and total dry matter intake (DMI) from 11 cows per treatment were measured during one 6-d measurement period using the sulphur hexafluoride tracer gas technique. Individual pasture DMI was determined using TiO2 and indigestible neutral detergent fibre (NDF). Milk yield decreased by approximately 12% when feeding the high nitrate diet compared with the control and low nitrate diets. Although total DMI was unaffected by treatment, concentrate DMI decreased linearly (5.5–3.7 kg/d) while pasture DMI increased linearly (9.1–11.4 kg/d) with increasing dietary nitrate addition. Methane production (313–280 g/d), CH4 yield (21.8–18.7 g/kg of DMI) and CH4 energy per gross energy intake (6.9–5.9%) tended to decrease linearly with increasing dietary nitrate addition. Diurnal ruminal pH of the high nitrate group was greater, for selective periods after concentrate feeding, than the control and low nitrate groups. Spot sample ruminal pH (6.2–6.3) tended to increase while total volatile fatty acid (VFA) concentration (99.9–104 mM/L) increased quadratically with increasing dietary nitrate addition. Individual VFA concentrations were unaffected by treatment. Rate of NDF disappearance (2.4–2.8%/h) after 18 h of ruminal incubation tended to increase quadratically with increasing dietary nitrate addition. Dietary nitrate fed to grazing dairy cows tended to decrease CH4 emissions while improving the fibrolytic environment of the rumen. However, when feeding high levels of dietary nitrate a decrease in milk yield could be expected due to a decrease in concentrate DMI.

Influence of the addition of exogenous xylanase with or without pre-incubation on the in vitro ruminal fermentation of three fibrous feeds

The effects of the exogenous fibrolytic enzyme (ENZ) commercial preparation Dyadic® xylanase PLUS (Dyadic International, Inc., Jupiter, USA), containing endo-1,4-β-d-xylanase, on ruminal fermentation of maize stover, oat straw, and sugarcane bagasse were examined using the in vitro gas production (GP) technique. The ENZ commercial preparation was added at 0 (control), 60 (low), 120 (medium), and 240 (high) µg/g dry matter of substrate, and at two times of application (direct addition just before fermentation or with a 72-h pre-incubation before fermentation). Ruminal GP volumes were recorded at 2, 4, 6, 8, 10, 12, 14, 24, and 48 h of incubation, and substrate degradability and concentration of fermentation end-products (volatile fatty acids, ammonia, methane) in the cultures were determined at 48 h of incubation. Increased (P < 0.05) GP volume was observed in fibrous feeds treated with ENZ compared with untreated substrates. The pre-incubation vs the direct addition of ENZ resulted in greater GP volume (P < 0.05) with the three tested feeds. Enzyme addition decreased (P < 0.05) rumen pH compared to control when maize stover and sugarcane bagasse were incubated. Ammonia-N and total volatile fatty acids (VFA) were not affected (P > 0.05) by ENZ application in maize stover and oat straw. However, total and individual VFA concentrations, and CH4 and CO2 volumes were greater (P < 0.05) when sugarcane bagasse was incubated with 240 µg ENZ/g (P < 0.05). It can be concluded that the application of endo-1,4-β-d-xylanase enhances rumen fermentation of roughages, although the magnitude of the effects depends on the fibrous substrate fermented, the time of application, and the amount of enzyme added.

Effect of trace minerals and starch on digestibility and rumen fermentation in diets for dairy heifers

The objective of this study was to evaluate the effect of different forms of trace minerals (TM) and the use of different starch levels in dairy heifer diets on rumen fermentation and digestibility. Eight rumen cannulated dairy heifers (15.4±0.8mo of age and 438.31±18.08kg of body weight) were subjected to a split-plot, 4×4 Latin square design with 19-d periods: 15d of adaptation and 4d of sampling. The whole-plot factor was type of TM; organic as proteinates (OTM) or inorganic sulfates (ITM), and the subplot was starch level (3.54, 12.95, 22.25, and 31.73%). Total collection of feces and urine was completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled on d 18 to 19 at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and volatile fatty acid (VFA) concentrations. Plasma samples were collected to evaluate TM concentrations and enzymatic activity for ceruloplasmin, glutathione peroxidase, and superoxide dismutase. Starch level affected pH, individual VFA concentrations, and nutrient excretion. Trace mineral intake was lower for OTM compared with ITM. No effect of TM form on dry matter digestibility was detected, but as level of starch increased, diet dry matter digestibility increased. Rumen pH was lower for diets with OTM, which is consistent with higher total VFA production and butyrate proportion observed for heifers fed OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and higher urine excretion, which increased total manure production. Total excretion of TM was not different by treatment. Blood plasma mineral concentration was not different between treatments except for Mn, which was higher for OTM. Enzymatic activity was not affected by treatments. Mineral intake was reduced and blood mineral levels were not different, suggesting enhanced absorption of OTM compared with ITM. In conclusion, based on rumen pH, VFA production, and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed to a greater extent than ITM. Also, TM form affected fecal moisture and urine excretion, suggesting that ITM may stimulate water intake.

Effects of tea seed saponin supplementation on physiological changes associated with blood methane concentration in tropical Brahman cattle

A 59-day experiment compared the effects of increasing tea seed (Camellia sinensis L.) saponin (TSS) supplementation on dry matter intake (DMI), liveweight (LW), rumen fermentation, methanogenesis, blood biochemistry and animal tolerance. Six, 10, 15, 20, 25 and 30 g of powder TSS were dissolved during 5, 7, 4, 3, 3 and 2 days, respectively, and infused into the rumen of four rumen-cannulated Brahman steers (234 ± 13.6 kg LW; least-squares means ± s.e.m.) or mixed in the basal diet [BD: 0.15 Rhodes grass (Chloris gayana) hay plus a high-grain feed (0.85)] of two non-cannulated (253 ± 19.3 kg) steers. Overall, DMI was not affected, by the sequential infusion of TSS (5.3 ± 0.15 kg) or addition to the BD (5.4 ± 0.18 kg), but relative to all diets, 6 g of TSS supplementation reduced DMI (P &lt; 0.05), while the administration above 30 g of the supplement was associated with significantly (P &lt; 0.001) reduced DMI, scours and bloat disorders. Clinical symptoms disappeared 8 days after withdrawal of the supplement. LW increased with time (P &lt; 0.05) and the final LW was similar for cannulated (258 ± 13.6 kg) and non-cannulated (276 ± 19.3 kg) steers. Saponin supplementation reduced total volatile fatty acid (VFA) concentration (P &lt; 0.05), modified pattern of individual molar VFA concentrations and moderately increased ruminal pH (P &lt; 0.05). Cannulated and non-cannulated steers fed the BD had similar daily (g) methane or yield (CH4 g/kg DMI) emissions while in respiratory chambers. However, compared with cannulated (8.0 ± 1.20 ng/mL) animals, the addition of 30 g of TSS in the BD increased (P &lt; 0.01) blood CH4 concentration in non-cannulated (15.6 ± 1.74 ng/mL) animals. Diets supplemented with 30 g of TSS were associated with higher chloride (P &lt; 0.01) and alkaline phosphatase (P &lt; 0.05) blood concentrations, and lower serum concentrations of potassium and urea nitrogen (P &lt; 0.01), iron and total lipase (P &lt; 0.05), than was the BD. It was concluded that higher levels of TSS supplement may evoke physiological changes in the animal. However, the potential CH4 mitigation effect of this form of saponin in tropical cattle needs further investigation, alongside the derived response of the rumen microbial ecology to the tested range of supplementation.

Effects of soybean meal treated with tannins extracted from pistachio hulls on performance, ruminal fermentation, blood metabolites and nutrient digestion of Holstein bulls

This experiment was conducted to study the effects of soybean meal (SBM) treated with various amounts of tannins extracted from pistachio hulls on performance, ruminal fermentation, nutrient digestibility, and blood metabolites in Holstein bulls. Twenty-eight Holstein bull calves (256±63kg body weight) were randomly assigned to one of four dietary treatments for 14 weeks. Each treatment group received one of four SBM treatments included in a total mixed ration (TMR) at a constant rate of 105g/kg DM. Soybean meal was treated with pistachio extract concentrate (PEC), which contained 111.4g/kg total phenol and 71.3g/kg total tannin per dry matter of extract, at four experimental treatment rates of 0 (SBM-0), 5 (SBM-5), 10 (SBM-10), and 15 (SBM-15) kg PEC per 100kg SBM on a dry matter basis. Blood samples were collected monthly and ruminal fluid samples were collected on d 83 and d 85 of treatment. Treatment of SBM with PEC did not affect final body weight or dry matter intake (DMI), but adding PEC linearly increased average daily gain (L, P=0.001) and feed efficiency (L, P=0.001). Inclusion of PEC linearly decreased ruminal ammonia nitrogen (L, P=0.02) and total protozoal population (L, P=0.002), but did not affect concentrations of total volatile fatty acids (VFA), individual VFA or pH in the rumen. Total tract nutrient digestibility and blood metabolites were unaffected by SBM treatment with PEC, except for concentrations of albumin and total protein in plasma, which increased linearly (L, P=0.004 and P=0.001, respectively) with increasing PEC treatment. These results suggest that PEC supplementation decreases ruminal ammonia nitrogen concentration and total protozoa population and improves growth performance of Holstein bulls.

Hydrate sodium calcium aluminosilicate does not reduce rumen lipopolysacharide concentrations in cows

The efficacy of hydrate sodium calcium aluminosilicate (HSCAS) to reduce the concentrations of free lipopolysaccharide (LPS) in rumen fluid of cows was investigated. Six, rumen-fistulated crossbred Holstein, non-pregnant, dry cows were randomly assigned to three experimental rations in a study with a replicated 3×3 Latin square design with 28-d periods. During the first 20 days of each experimental period, cows were offered concentrate (5.4kg dry matter; DM) without HSCAS and rice straw ad libitum. On day 21, cows were fasted for 12h prior to commencement of a 7-d measurement period during which time cows were offered concentrate (10.5kg DM) containing either 0, 5 or 10g/kg of HSCAS and 1.5kg DM rice straw. Rumen fluid was collected on days 1, 3 and 7 during the measurement period for analysis of pH, LPS and volatile fatty acids (VFA). Supplemental HSCAS did not affect the pH or the concentrations of total and individual VFA in the ruminal fluid. Mean postprandial rumen pH was reduced to values below 5.6 at all times. Rumen LPS concentrations significantly increased from day 1 to 7 during each measurement period with values ranging from 4489 to 104,000EU/mL but they were not significantly affected by supplemental HSCAS.

Impact of oxalic acid on rumen function and bacterial community in sheep

Oxalic acid (OA) is a secondary compound occurring in a wide range of plants consumed by ruminants, especially in saline lands or in arid and semi-arid regions. However, its impact on the rumen microbial community and its changes over time, as well as the potential consequences on ruminal function, remain unknown. To examine this impact, five ewes fitted with a ruminal cannula and fed low-quality grass hay were dosed daily with 0.6 mmol of OA/kg body weight through the cannula for 14 days. On days 0 (before the start), 4, 7 and 14 of the administration period, samples of ruminal digesta were collected throughout the day (0, 3, 6 and 9 h after the morning feeding) for analysis of the bacterial community and fermentation parameters (pH, ammonia and volatile fatty acid (VFA) concentrations). In addition, two feedstuffs were incubated in situ using the nylon bag technique to estimate ruminal degradation. Terminal restriction fragment length polymorphism was employed to monitor the dynamics of total bacteria, and quantitative real-time PCR was used to investigate the abundance of the oxalate-degrading Oxalobacter formigenes. Neither pH nor total VFA concentrations were affected. Nevertheless, OA dosing altered molar proportions of most individual VFA and ammonia concentrations (P < 0.001). The dry matter disappearance of alfalfa hay was reduced on days 7 and 14 and that of barley straw only on day 7 (P < 0.01). These slight changes were related to others observed in the relative frequency of a number of terminal restriction fragments. Variations in the ruminal microbiota occurred rapidly with OA administration, which did not modify the bacterial diversity significantly but altered the structure of the community. However, many of these changes were reversed by the end of the experiment, with no significant differences between days 0 and 14 of dosing. These results suggest a rapid adaptation of the rumen bacterial community linked to the estimated increase in the abundance of O. formigenes (from 0.002% to 0.007% of oxc gene in relation to the total bacteria 16S rDNA; P < 0.01), which is assumed to be responsible for oxalate breakdown.

Determination of Volatile Fatty Acids from Raw Natural Rubber Drying Activity by Thermal Desorption-Gas Chromatography

Malodourous emission from raw natural rubber (NR) processing activities has become a public nuisance since residential and public development areas are gradually expanding near raw NR processing factories. The malodourous vapour mainly consists of volatile fatty acids (VFA) released from the breakdown of non-rubber constituents during drying stage of the raw rubber processing. An improved sampling methodology to characterise and monitor VFA from the drying stage was implemented. This study focused on the drying stage as the major source of malodour in the raw rubber processing. The thermal desorption-gas chromatography technique enabled direct sampling of air pollutants with minimal errors. It was found that acetic acid and propionic acids were present with highest concentrations. In general, concentrations of individual VFA varied throughout the drying stage. The raw NR processing factories were able to eliminate more than 71 % of total VFA using the relevant water scrubber treatment systems. The malodour characterization technique used in this study provides new technical information useful to develop more efficient malodour control systems for the raw NR processing industry.

Influence of polyethylene glycol on in vitro gas production profiles and microbial protein synthesis of some shrub species

The aim was to determine effects of addition of polyethylene glycol (PEG) on in vitro gas production and microbial protein synthesis of the shrub species Acacia constricta, Acacia shaffneri, Calliandra eriophylla, Condalia lycioides, Cordia parvifolia, Larrea tridentata and Mimosa biuncifera, which are commonly consumed by grazing small ruminants in semiarid regions of Mexico despite the abundance of tannins in their foliage. Three individual samples (a minimum of 10 plants of each) of each shrub species were collected from different areas and prepared for chemical and secondary metabolite analysis. In vitro evaluations for each sample of each shrub species were completed in three incubation runs in different weeks using calibrated glass syringes in a 7×2 factorial design (i.e., 7 shrub species×2 treatments with or without PEG). In vitro gas production after 24 and 96h, partitioning factor (PF), metabolizable energy (ME) content, efficiency of microbial protein synthesis (EMPS), and volatile fatty acids (VFA) were determined. A shrub species×PEG interaction (P<0.05) only occurred for some VFA, such as C3, C4, C4i and C5i, concentrations. Relative to control, addition of PEG increased (P<0.05) the concentrations of individual VFA in A. shaffneri, C. lycioides and C. parvifolia. Interactions between shrub and PEG occurred (P<0.001) for all gas production parameters (i.e., b, k, IVGP24, IVGP48). The fractional rate of gas production and IVGP24h were highest in A. constricta and lowest (P<0.001) in A. shaffneri. L. tridentata had the highest PF and C. lycioides the lowest. A. constricta had the highest ME content. Purine content and EMPS differed (shrubs×PEG; P<0.001) among shrubs. Microbial protein synthesis was highest in M. biuncifera and lowest in C. eriophylla, while total VFA were highest in C. eriophylla. Incorporation of PEG increased (P<0.001) in vitro fermentation parameters and ME content with L. tridentata and C. lycioides being the highest. PEG also promoted reductions in the EMPS and PF values. In vitro fermentation variables such as fractional rate of gas production, VFA concentrations and EMPS support the potential of A. constricta, C. parvifolia and M. biuncifera as protein and energy sources for small ruminants in semiarid regions of North Mexico. Increments in gas production in these shrub species confirmed the affinity of PEG to bind condensed tannins and reduce EMPS.