The Effect of a Bacillus Probiotic and Essential Oils Compared to an Ionophore on the Rumen Microbiome Composition of Feedlot Cattle

The rising concern of antibiotic growth promoter use in livestock has necessitated the investigation into alternative feed additives. The effect of a probiotic and essential oils to an ionophore on the rumen microbiome composition of Bonsmara bulls raised under feedlot conditions was compared. Forty-eight Bonsmara weaners were allocated to four groups: a group with basal diet (CON) and three groups supplemented with monensin (MON), probiotic (PRO), and essential oils (EO). During the 120 days feeding period, rumen content was collected from four animals per group within each phase via a stomach tube for 16S rRNA and internal transcribed spacer (ITS) sequencing as well as volatile fatty acid analysis. In the starter phase, MON had a significantly lower acetate to propionate ratio and a higher Succinivibrionaceae abundance. The abundance of Lachnospiraceae was significantly higher in EO compared to MON. In the finisher phase, PRO had a significantly higher bacterial diversity. The alpha diversity did not differ between the fungal populations of the groups. The abundance of Proteobacteria was the lowest in PRO compared to the other groups. Limited variation was observed between the rumen microbiome composition of monensin compared to the other treatment groups, indicating that these alternatives can be considered.

Effect of Adding Extra Virgin Olive Oil to Hair Sheep Lambs' Diets on Productive Performance, Ruminal Fermentation Kinetics and Rumen Ciliate Protozoa

This study determined productive performance, ruminal fermentation kinetics and rumen ciliate protozoa in hair sheep lambs fed different levels of olive oil. Twenty-four growing lambs were used, with an initial live weight of 10.5 ± 2.9 kg, and randomly assigned into four treatments (six animals per treatment) containing increasing levels of extra virgin olive oil (0, 2, 4 and 6% of dry matter). Animals were fed for 80 days, and sampling was carried out weekly. Intake of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) differed between treatments (p < 0.05), with a linear and cubic tendency to decrease when oil concentrations were increased. Digestibility coefficients of OM, CP and NDF were not affected; however, the relationship between total intake and nutrient digestibility (DM, OM, NDF, ADF) increased with 2% DM olive oil. Compared with all treatments, the concentration of propionic acid increased by 16% with 4% olive oil. The intake of olive oil did not affect the protozoa population and live weight gain. Overall, the inclusion of olive oil in low concentrations (2% of DM) positively influences feed intake and nutrient digestibility in hair sheep lambs.

A Meta-Analysis of Essential Oils Use for Beef Cattle Feed: Rumen Fermentation, Blood Metabolites, Meat Quality, Performance and, Environmental and Economic Impact

The objective of this study was to see how dietary supplementation with essential oils (EOs) affected rumen fermentation, blood metabolites, growth performance and meat quality of beef cattle through a meta-analysis. In addition, a simulation analysis was conducted to evaluate the effects of EOs on the economic and environmental impact of beef production. Data were extracted from 34 peer-reviewed studies and analyzed using random-effects statistical models to assess the weighted mean difference (WMD) between control and EOs treatments. Dietary supplementation of EOs increased (p < 0.01) dry matter intake (WMD = 0.209 kg/d), final body weight (WMD = 12.843 kg), daily weight gain (WMD = 0.087 kg/d), feed efficiency (WMD = 0.004 kg/kg), hot carcass weight (WMD = 5.45 kg), and Longissimus dorsi muscle area (WMD = 3.48 cm2). Lower (p < 0.05) ruminal concentration of ammonia nitrogen (WMD = −1.18 mg/dL), acetate (WMD = −4.37 mol/100 mol) and total protozoa (WMD = −2.17 × 105/mL), and higher concentration of propionate (WMD = 0.878 mol/100 mol, p < 0.001) were observed in response to EOs supplementation. Serum urea concentration (WMD = −1.35 mg/dL, p = 0.026) and haptoglobin (WMD = −39.67 μg/mL, p = 0.031) were lower in cattle supplemented with EOs. In meat, EOs supplementation reduced (p < 0.001) cooking loss (WMD = −61.765 g/kg), shear force (WMD = −0.211 kgf/cm2), and malondialdehyde content (WMD = −0.040 mg/kg), but did not affect pH, color (L* a* and b*), or chemical composition (p > 0.05). Simulation analysis showed that EOs increased economic income by 1.44% and reduced the environmental footprint by 0.83%. In conclusion, dietary supplementation of EOs improves productive performance and rumen fermentation, while increasing the economic profitability and reducing the environmental impact of beef cattle. In addition, supplementation with EOs improves beef tenderness and oxidative stability.

Influence of diets supplemented with naturally protected or unprotected eucalyptus oil on methane production and lactating buffalo productivity

This study was designed to investigate the influence of naturally protected eucalyptus oil supplementation in a form of leaves (EUL) or mature seed capsules (EUS) compared to crude eucalyptus oil (EUO). The control group (G₁) received a diet containing concentrate feed mixture, fresh berseem, rice straw, and corn silage, whereas the G2, G3, and G4 animals have a diet supplemented with 200 g/head/day of EUL or EUS or 4 mL/head/day EUO, respectively. Supplementation of EUL or EUS increased NH₃-N, short-chain fatty acids, and concentrations of acetic acid in vitro. Bacterial total count, protozoa, and cellulolytic bacteria increased (P < 0.05) with EUL and EUS supplementation. Methane production dropped (P < 0.05) with EUS, EUL, and EUO supplementation. Milk fat decreased (P < 0.05) with EUO supplementation, while an adverse trend was shown for lactose. No differences in feed conversion were found among EUS, EUL, and EUO. Blood total protein, albumin, and urea increased (P < 0.05) with supplementation of EUL or EUS compared to EUO. EUO supplementation yielded increased (P < 0.05) AST, ALT, glucose, and creatinine. Supplementation with EUL, EUS, or EUO decreased (P < 0.05) DM, OM, and CP digestibility, while digestibility of EE with supplementation by EUL, EUS, or EUO was higher (P < 0.05). The digestion coefficient of NDF and ADF decreased (P < 0.05) with supplemental EUL, EUS, or EUO compared to the G1 diet. Feeding EUS increased the values of TDN and DCP compared to EUL, which increased than EUO. Our results confirm that the naturally protected form of leaves or seeds mitigates the undesirable effects of directly supplementing crude eucalyptus oil.

Influence of Phytogenic Feed Additive on Performance of Feedlot Cattle

This study evaluated the influence of a blended phytogenic feed additive on feed intake, feeding behavior, nutrient digestibility, and growth performance during feedlot adaptation, early, and late finishing periods as well as carcass traits. Twenty-six crossbred F1 Angus × Nellore bulls (19 mo ± 4 d) were housed in individually pens and fed a high-forage receiving diet for 7 days. At the end of the receiving period, bulls were weighted [initial shrunk body weight (SBW) 363 ± 20 kg], blocked by SBW and randomly assigned to two treatments; Control: without any additive or PHY: 150 ppm of a phytogenic feed additive fed throughout the adaptation and finishing phases. Bulls were transitioned through four steps over 18 days to a high-grain finishing diet (as % DM, 64% rehydrated corn grain silage, 19% corn gluten feed, 13% sugar cane bagasse and 4% minerals, urea, and vitamins mix). The finishing phase lasted 68 days, with mid-point measurements dividing early and late finishing period. The PHY group DMI was greater during adaptation and late finishing periods (P &lt; 0.05), with a tendency during early finishing period (P = 0.06). Number of daily meals was similar between treatments (P = 0.52), but an increased meal length was noted for PHY group (P &lt; 0.05), which contributed to their greater DMI. Diet digestibility remained similar between groups during the finishing periods (P &gt; 0.1). Ruminitis scores were low and liver abscess similar between treatments. Final SBW tended to be higher (P = 0.09) and hot carcass weight was greater for the PHY group (P &lt; 0.05), with no differences on dressing percentage, ribeye area and marbling score. In conclusion, the PHY treatment had positive effects on intake and carcass weight, without increasing metabolic disorders.

Nutritional Aspects of Ecologically Relevant Phytochemicals in Ruminant Production

This review provides an update of ecologically relevant phytochemicals for ruminant production, focusing on their contribution to advancing nutrition. Phytochemicals embody a broad spectrum of chemical components that influence resource competence and biological advantage in determining plant species' distribution and density in different ecosystems. These natural compounds also often act as plant defensive chemicals against predatorial microbes, insects, and herbivores. They may modulate or exacerbate microbial transactions in the gastrointestinal tract and physiological responses in ruminant microbiomes. To harness their production-enhancing characteristics, phytochemicals have been actively researched as feed additives to manipulate ruminal fermentation and establish other phytochemoprophylactic (prevent animal diseases) and phytochemotherapeutic (treat animal diseases) roles. However, phytochemical-host interactions, the exact mechanism of action, and their effects require more profound elucidation to provide definitive recommendations for ruminant production. The majority of phytochemicals of nutritional and pharmacological interest are typically classified as flavonoids (9%), terpenoids (55%), and alkaloids (36%). Within flavonoids, polyphenolics (e.g., hydrolyzable and condensed tannins) have many benefits to ruminants, including reducing methane (CH4) emission, gastrointestinal nematode parasitism, and ruminal proteolysis. Within terpenoids, saponins and essential oils also mitigate CH4 emission, but triterpenoid saponins have rich biochemical structures with many clinical benefits in humans. The anti-methanogenic property in ruminants is variable because of the simultaneous targeting of several physiological pathways. This may explain saponin-containing forages' relative safety for long-term use and describe associated molecular interactions on all ruminant metabolism phases. Alkaloids are N-containing compounds with vast pharmacological properties currently used to treat humans, but their phytochemical usage as feed additives in ruminants has yet to be exploited as they may act as ghost compounds alongside other phytochemicals of known importance. We discussed strategic recommendations for phytochemicals to support sustainable ruminant production, such as replacements for antibiotics and anthelmintics. Topics that merit further examination are discussed and include the role of fresh forages vis-à-vis processed feeds in confined ruminant operations. Applications and benefits of phytochemicals to humankind are yet to be fully understood or utilized. Scientific explorations have provided promising results, pending thorough vetting before primetime use, such that academic and commercial interests in the technology are fully adopted.

The effect of diets supplemented with Coriandrum sativum seeds on carcass performance, immune system, blood metabolites, rumen parameters and meat quality of lambs

A trial was conducted to investigate the effects of dietary Coriandrum sativum seeds on carcass performance, immune system, blood metabolites, rumen parameters and meat quality of Lambs. 16 Sanjabi lambs of 27 ± 5.1 kg during post-weaning (97 d of age) period were randomly selected. Four diets including 0, 1, 3, and 5% coriander seeds, replaced by Alfa alfa in the diet, were considered. A 30:70 alfalfa hay: concentrate diet for a period of time (97 to 187 d of age) was used. The results showed that feed intake was significantly increased by adding coriander seeds, linearly. There was no significant difference for apparent digestibility of crude protein, crude fat, neutral and acidic detergent fiber, crude ash, rumen fluid pH and ammonia nitrogen at 0, 2 and 4 h after feeding, Meat dry matter, ash, crude protein and fat, and the meat’s fatty acid profile (p > 0.05). Dietary coriander seeds had a significant effect on neutrophils, lymphocytes, monocytes and eosinophil’s (in days 7 and 14 of trial) and blood metabolites at the middle of trial. Obtained results suggested that supplementation of coriander seed may have limited effects on nutrient digestibility, ruminal parameters, meat quality, blood cells and metabolites.

Diet supplementation with thyme oil and its main component thymol failed to favorably alter rumen fermentation, improve nutrient utilization, or enhance milk production in dairy cows

Phenolic compounds and essential oils with high content of phenolic compounds have been reported to exert antimicrobial activities in vitro. The objective of this study was to determine the effects of dairy cow diet supplementation with thyme oil and its main component thymol on intake and total-tract apparent digestibility of nutrients, rumen fermentation characteristics, ruminal protozoa, nitrogen excretion, and milk production. For this aim, we used 8 multiparous, ruminally cannulated Holstein cows in a replicated 4 × 4 Latin square design (28 d periods), balanced for residual effects. Cows were fed 1 of the 4 following experimental treatments: total mixed ration (TMR) with no additive (control); TMR + monensin [24 mg/kg of dry matter (DM)]; TMR + thyme oil (50 mg/kg of DM); and TMR + thymol (50 mg/kg of DM). Compared with the control diet, feeding thyme oil or thymol had no effect on DM intake, nutrient total-tract apparent digestibility, total N excretion, ruminal pH, ammonia concentration, total volatile fatty acid (VFA) concentration, or acetate:propionate ratio. Ruminal protozoa density was not modified by thyme oil, but decreased with thymol supplementation. Supplementation with thyme oil or thymol did not affect milk production, milk composition, or efficiency of milk production. Neither thyme oil nor thymol affected efficiency of dietary N use for milk N secretion (N intake/milk N). Supplementation with monensin tended to decrease DM intake (-1.2 kg/d) and milk fat yield. Total-tract apparent digestibility of nutrients did not differ between cows fed monensin and cows fed the control diet. Total VFA concentration was not changed by monensin supplementation compared with control, but adding monensin shifted the VFA profile toward more propionate and less acetate, resulting in a decrease of acetate:propionate ratio. Protozoa density and ammonia concentration were lower in the ruminal content of cows fed monensin compared with that of cows fed the control diet. Total N excretion was not affected by monensin supplementation. Likewise, efficiency of use of dietary N for milk N secretion was unchanged in cows fed monensin. The results of this study contrasted with the claimed in vitro antimicrobial activity of thyme oil and thymol: we observed no positive effects on rumen metabolism (i.e., N and VFA) or milk performance in dairy cows. Under the conditions of this study, including thyme oil or thymol at 50 mg/kg of DM had no benefits for rumen fermentation, nutrient utilization and milk performance in dairy cows.

Thyme essential oil for sheep: effect on rumen fermentation, nutrient digestibility, nitrogen metabolism, and growth

ABSTRACT Two experiments were conducted to evaluate the effect of thyme (Thymus vulgaris) essential oil (EO) doses on rumen fermentation, nutrient digestibility, and nitrogen metabolism, as well as performance and coccidia oocyst discharge. In experiment I, 20 rumen-cannulated wethers received the experimental diets containing 80% dry matter (DM) of haylage and 20% DM of concentrate. Treatments were 25mg of monensin/kg DM or doses of 1.25, 2.50, or 3.75g of thyme EO/kg DM. In experiment II, 50 ewe lambs received the same diets from experiment I, including a diet without feed additives. Wethers fed with diets containing 1.25g/kg DM of thyme EO had higher molar proportion of propionate (P= 0.03) and butyrate (P< 0.01), and lower (P= 0.04) acetate to propionate ratio than other treatments. Adding thyme EO to diets increased (P= 0.02) nitrogen retention compared to monensin. The performance of ewe lambs was not affected (P≥ 0.05) by treatments. However, lambs fed monensin had a lower (P= 0.04) number of coccidia oocyst discharge than others. Adding 1.25g/kg DM of thyme EO in high-forage diet improved ruminal fermentation. Thyme EO enhanced nitrogen metabolism, however, it did not improve performance.

Effect of cinnamaldehyde on feed intake, rumen fermentation, and nutrient digestibility, in lactating dairy cows1

The objective of this study was to evaluate the effect of cinnamaldehyde, on feed intake, rumen fermentation, nutrient digestibility, milk yield, and components in lactating dairy cows. Six lactating Holstein dairy cows (3 ruminally cannulated and 3 noncannulated) averaging 263 ± 41 d in milk (DIM) and 754 ± 45 kg of BW at the beginning of the study were used. Cows were randomly assigned to 1 of 3 treatments in a replicated 3 × 3 Latin square design with 19 d periods (14 d for diet adaptation and 5 d for sample collection). Treatments were 0, 2, or 4 mg/kg of BW of cinnamaldehyde. Cinnamaldehyde was mixed with 40 g of corn meal and top-dressed onto the total mixed ration (TMR). Diet was fed as a TMR and contained 37% corn silage, 18.5% mixed-mostly grass silage, 24.5% energy supplement, 16.5% protein supplement, and 3.5% vitamin and mineral mix on a DM basis. The dietary nutrient composition averaged 15.1% CP, 37.8% NDF, and 24.7% ADF. Cows were fed and milked twice daily. No differences were observed for DMI (mean = 24.6 kg/d), milk yield (mean = 28.4 kg/d), 3.5% fat-corrected milk (FCM; mean = 30.6 kg/d), and 3.5% energy-corrected milk (ECM; mean = 30.7 kg/d). The dose of cinnamaldehyde did not have any effect on milk components, rumen fermentation, or pH. There were no differences in nutrient digestibility, but there was a trend for a quadratic effect for DM digestibility (P = 0.09): 74.4%, 76.3%, and 73.7% for treatments 0, 2, and 4 mg/kg of BW of cinnamaldehyde, respectively. A linear effect (P = 0.02) and a quadratic effect (P < 0.02) observed for urinary urea N and a quadratic effect (P = 0.03) for allantoin and total purine derivatives with the 2 mg/kg treatment being the lesser value. These data suggest that cinnamaldehyde at these dosages may have an antimicrobial effect in the rumen as suggested by a lesser concentration of urinary total purine derivatives. Overall, supplementing lactating dairy cows with cinnamaldehyde had no effect on feed intake, milk yield, or milk components. However, it appears that cinnamaldehyde has a negative effect on rumen microbial protein synthesis as suggested by the reduced concentration of urinary purine derivatives.

Effect of Encapsulated Nitrate and Microencapsulated Blend of Essential Oils on Growth Performance and Methane Emissions from Beef Steers Fed Backgrounding Diets

A long-term study (112 days) was conducted to examine the effect of feeding encapsulated nitrate (NO₃-), microencapsulated blend of essential oils (EO), and their combination on growth performance, feeding behavior, and enteric methane (CH₄) emissions of beef cattle. A total of 88 crossbred steers were purchased and assigned to one of four treatments: (i) control, backgrounding high-forage diet supplemented with urea (1.17% in dietary DM); (ii) encapsulated NO₃- (EN), control diet supplemented with 2.5% encapsulated NO₃- as a replacement for urea (1.785% NO₃- in the dietary DM); (iii) microencapsulated blend of EO (MBEO), control diet supplemented with 150 mg/kg DM of microencapsulated blend of EO and pepper extract; and (iv) EN + MBEO, control diet supplemented with EN and MBEO. There was no interaction (p ≥ 0.080) between EN and MBEO on average dry matter intake (DMI), average daily gain (ADG), gain to feed ratio (G:F), feeding behavior, and CH₄ emission (using GreenFeed system), implying independent effects of feeding EN and MBEO. Feeding MBEO increased CH₄ production (165.0 versus 183.2 g/day; p = 0.005) and yield (18.9 versus 21.4 g/kg DMI; p = 0.0002) but had no effect (p ≥ 0.479) on average DMI, ADG, G:F, and feeding behavior. However, feeding EN had no effect on ADG and G:F (p ≥ 0.119) but reduced DMI (8.9 versus 8.4 kg/day; p = 0.003) and CH₄ yield (21.5 versus 18.7 g/kg DMI; p < 0.001). Feeding EN slowed (p = 0.001) the feeding rate (g of DM/min) and increased (p = 0.002) meal frequency (events/day). Our results demonstrate that supplementing diets with a blend of EO did not lower CH₄ emissions and there were no advantages of feeding MBEO with EN. Inclusion of EN as a replacement for urea reduced CH₄ emissions but had no positive impact on animal performance.

Influence of yeast culture and feed antibiotics on ruminal fermentation and site and extent of digestion in beef heifers fed high grain rations1

The study objective was to investigate the effects of site of delivering Saccharomyces cerevisiae fermentation product (SCFP) on ruminal pH and fermentation characteristics, and the site and extent of feed digestion in the digestive tract of beef heifers fed high-grain diets. Examining the ruminal and postruminal effects of SCFP is important for understanding the potential use of SCFP as an alternative for current industry-standard antibiotics used in beef cattle rations. Five beef heifers (initial BW = 561 ± 11.7 kg) equipped with ruminal and duodenal cannulas were used in a 5 × 5 Latin square design with 28-d periods, including 21 d for adaption and 7 d for data collection. Five treatments were as follows: 1) control diet that contained 10% barley silage and 90% barley concentrate mix (DM basis); 2) control diet supplemented with antibiotics (ANT; 330-mg monensin/d and 110-mg tylosin/d per head); 3) ruminal (top dress) delivery of SCFP (rSCFP; NaturSafe, Diamond V, 18-g SCFP/d); 4) duodenal delivery of SCFP (dSCFP; 18-g SCFP/d, via duodenal cannula); and 5) a combination of rSCFP and dSCFP (rdSCFP; 18-g rSCFP and 18-g dSCFP). Intake of DM tended (P < 0.10) to be greater by heifers fed rdSCFP than those fed control, ANT and rSCFP diets. Minimum ruminal pH was greater (P < 0.05) with rSCFP than control and rdSCFP treatments. The duration of ruminal pH < 5.6 tended (P < 0.10) to be less with rSCFP than control and ANT. Heifers fed the rSCFP diet had greater (P < 0.03) protozoa counts and proportion of acetate than the other treatments. Nutrient flows to the duodenum did not differ (P > 0.19), whereas the amount of truly fermented OM was greater (P < 0.03) with rdSCFP than the other treatments. Ruminal OM digestibility was highest with rSCFP and rdSCFP, intermediate with dSCFP and ANT, and lowest with control (P < 0.03). Intestinal digestibility was similar among treatments. As a result, total tract digestibility of OM (P < 0.07) and NDF (P < 0.01) was greater with rSCFP and rdSCFP than control and ANT. Fecal IgA concentration was highest with ANT, intermediate with dSCFP and rdSCFP, and lowest with control and rSCFP (P < 0.03). These results demonstrate that feeding SCFP improved stability of ruminal pH and digestibility of OM and NDF. Delivery of SCFP to the duodenum appeared to have little effect on nutrient digestibility but improved intestinal immune response. Feeding SCFP performed better or at least equal to antibiotics currently used in beef cattle rations and could be a natural alternative for beef cattle production.

Effects of phytonutrients alone or in combination with monensin on productivity in lactating dairy cows

This experiment was conducted to investigate the effects of phytonutrients, compared with monensin as a positive control, on productivity, milk fatty acids, fat mobilization, and blood cells in lactating dairy cows. Thirty-six Holstein cows were used in a 9-wk randomized complete block design study. Following a 2-wk covariate period, cows were blocked by days in milk, parity, and milk yield and randomly assigned to 1 of 3 treatments (12 cows/treatment): 450 mg/cow per day of monensin (MO), 250 mg/cow per day of capsicum plus 450 mg/cow per day of MO (MOCAP), and 1,000 mg/cow per day of a mixture of cinnamaldehyde, eugenol, and capsicum (CEC). Dry matter intake and milk yield were not affected by treatment. Supplementation of CEC increased feed efficiency compared with MO, but did not affect feed efficiency on an energy-corrected milk basis. Milk composition (fat, protein, and lactose), milk fatty acid profile, and blood concentrations of nonesterified fatty acids and β-hydroxybutyrate were also not affected by treatment. The expression of hormone-sensitive lipase in adipose tissues tended to increase for MOCAP compared with MO. Counts of total white blood cell, neutrophils, lymphocytes, eosinophils, and basophils were not affected by treatment, although monocytes count tended to be decreased by CEC. Treatments had no effect on red blood cells, hemoglobin, and platelets. Results indicate that dietary supplementation of CEC and capsicum had no production or other effects in dairy cows, compared with MO, except CEC increased feed efficiency and tended to decrease blood monocytes count.

Impact of phytogenic feed additives on growth performance, nutrient digestion and methanogenesis in growing buffaloes

Twenty growing buffalo calves were fed on a basal diet consisting of wheat straw and concentrate mixture in a randomised block design, to study the effect of feeding phytogenic feed additives on growth performance, nutrient utilisation and methanogenesis. The four groups were viz. control (no additive), Mix-1 (ajwain oil and lemon grass oil in 1 : 1 ratio @ 0.05% of dry matter intake), Mix-2 (garlic and soapnut in 2 : 1 ratio @ 2% of DMI) and Mix-3 (garlic, soapnut, harad and ajwain in 2 : 1 : 1 : 1 ratio @ 1% of DMI). The experimental feeding was continued for a period of 8 months. A metabolism trial was conducted after 130 days of feeding. Methane emission from animals was measured by open-circuit indirect respiration calorimeter. The feed conversion efficiency was higher by 9.5% in Mix-1, 7% in Mix-2 and 10.2% in Mix-3 group than in control. The digestibility of nutrients was similar except crude protein, which was improved (P < 0.05) in treatment groups. All buffalo calves were in positive nitrogen balance. Comparative faecal nitrogen decreased and urinary nitrogen increased in all the supplemented groups compared with in the control group. Methane emission (in terms of L/kg dry matter intake and L/kg digestible dry matter intake) was reduced by 13.3% and 17.8% in Mix-1, 10.9% and 13.5% in Mix-2 and 5.1% and 9.8% in Mix-3 groups as compared with control. When expressed in L/kg organic matter intake and L/kg digestible organic matter intake, methane production was reduced by 13.3% and 16.7% in Mix-1, 10.9% and 12.9% in Mix-2 and 5.1% and 8.4% in Mix-3 groups compared with the control group. These feed additives inhibited methane emission without adversely affecting feed utilisation by the animals. The faecal energy, urinary energy and methane energy losses were not affected (P > 0.05) due to feeding of these additives. Further, long-term feeding experiments should be conducted on a large number of animals to validate these effects before they can be recommended for use at a field level.

Chemistry, Antimicrobial Mechanisms, and Antibiotic Activities of Cinnamaldehyde against Pathogenic Bacteria in Animal Feeds and Human Foods

Cinnamaldehyde is a major constituent of cinnamon essential oils produced by aromatic cinnamon plants. This compound has been reported to exhibit antimicrobial properties in vitro in laboratory media and in animal feeds and human foods contaminated with disease-causing bacteria including Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. This integrated review surveys and interprets our current knowledge of the chemistry, analysis, safety, mechanism of action, and antibiotic activities of cinnamaldehyde in food animal (cattle, lambs, calves, pigs, poultry) diets and in widely consumed liquid (apple, carrot, tomato, and watermelon juices, milk) and solid foods. Solid foods include various fruits (bayberries, blueberries, raspberries, and strawberries), vegetables (carrots, celery, lettuce, spinach, cucumbers, and tomatoes), meats (beef, ham, pork, and frankfurters), poultry (chickens and turkeys), seafood (oysters and shrimp), bread, cheese, eggs, infant formula, and peanut paste. The described findings are not only of fundamental interest but also have practical implications for food safety, nutrition, and animal and human health. The collated information and suggested research needs will hopefully facilitate and guide further studies needed to optimize the use of cinnamaldehyde alone and in combination with other natural antimicrobials and medicinal antibiotics to help prevent and treat food animal and human diseases.

Diet supplementation with cinnamon oil, cinnamaldehyde, or monensin does not reduce enteric methane production of dairy cows

This study was conducted to evaluate the effect of dietary addition of cinnamon oil (CIN), cinnamaldehyde (CDH), or monensin (MON) on enteric methane (CH4) emission in dairy cows. Eight multiparous lactating Holstein cows fitted with ruminal cannulas were used in a replicated 4×4 Latin square design (28-day periods). Cows were fed (ad libitum) a total mixed ration ((TMR); 60 : 40 forage : concentrate ratio, on a dry matter (DM) basis) not supplemented (CTL), or supplemented with CIN (50 mg/kg DM intake), CDH (50 mg/kg DM intake), or monensin (24 mg/kg of DM intake). Dry matter intake (DMI), nutrient digestibility, N retention, and milk performance were measured over 6 consecutive days. Ruminal degradability of the basal diet (with no additive) was assessed using in sacco incubations (0, 2, 4, 8, 16, 24, 48, 72 and 96 h). Ruminal fermentation characteristics (pH, volatile fatty acids (VFA), and ammonia (NH3)) and protozoa were determined over 2 days. Enteric CH4 emissions were measured over 6 consecutive days using the sulfur hexafluoride (SF6) tracer gas technique. Adding CIN, CDH or MON to the diet had no effects on DMI, N retention, in sacco ruminal degradation and nutrient digestibility of the diet. Ruminal fermentation characteristics and protozoa numbers were not modified by including the feed additives in the diet. Enteric CH4 emission and CH4 energy losses averaged 491 g/day and 6.59% of gross energy intake, respectively, and were not affected by adding CIN, CDH or MON to the diet. Results of this study indicate that CIN, CDH and MON are not viable CH4 mitigation strategies in dairy cows.

Structure-Activity Relationship of Condensed Tannins and Synergism with trans-Cinnamaldehyde against Caenorhabditis elegans

Parasitic gastrointestinal nematodes (GIN) of livestock are increasingly developing resistance to synthetic nematocidal drugs. Moreover, the use of nematocides can induce ecotoxicity by affecting free-living nematodes. Condensed tannins (CT) are a structurally diverse group of bioactive plant compounds possessing anthelmintic activity against GIN. We investigated the relationship between the chemical structure of contrasting, purified CT and nematocidal effects using Caenorhabditis elegans. We also explored whether the nematocidal activity of CT could synergize with trans-cinnamaldehyde (CIN). A nonsignificant correlation was evident between the ability of CT fractions to inhibit C. elegans motility and the molar proportion of prodelphinidin subunits in purified CT samples. Synergistic inhibition of motility was achieved by combinations of CT and CIN. Galloylation of procyanidins was also a key factor for synergy. To increase the nematocidal effect of CT, plant sources containing CT with specific structural features could be selected and combined with compounds acting in synergy.

Critical evaluation of essential oils as rumen modifiers in ruminant nutrition: A review

Ruminant livestock systems contribute significantly to emission of methane, a potent greenhouse gas as they waste a portion of the ingested energy (2-15%) as methane and a large proportion (75-95%) of the ingested nitrogen as ammonia. Recently, numerous researches have been conducted to evaluate plant secondary metabolites, including essential oils (EO), as natural feed additives in ruminant nutrition and to exploit their potential to improve rumen fermentation efficiency. Essential oils appeared to be very promising compounds as they selectively reduced methane production and protein breakdown in both in vitro and in vivo studies. However, in some studies, the use of EO as feed additives was accompanied with decreased feed degradability and lowered volatile fatty acid. These adverse effects could be attributed to their broad and often non-specific antimicrobial activities within the rumen. Future research should be directed to identification of the active and useful EO compounds, optimization of EO doses, and use of a whole-farm approach with a focus on animal welfare, performance and economic benefits.

Effects of a specific blend of essential oils on apparent nutrient digestion, rumen fermentation and rumen microbial populations in sheep fed a 50:50 alfalfa hay:concentrate diet

Objective

An experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep.

Methods

Six sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet.

Results

Ruminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation.

Conclusion

The results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.

Comparison on the fatty acid profiles of liver, subcutaneous fat and muscle from feedlot steers finished on diets supplemented with or without cinnamaldehyde or monensin

BACKGROUND

Cinnamaldehyde (CIN) is the main active component of cinnamon (Cinnamomum cassia) oil and has been tested as alternative feed additive in cattle production. Little information was available on the effect of dietary CIN in comparison to monensin (MO) on beef fatty acid (FA) profile. This study analyzed FA profiles of liver, subcutaneous fat and pars costalis diaphragmatis (PCD) muscle obtained from steers (n = 70) finished on diets: control, a barley grain-silage feedlot diet; 330 mg/head.day MO; and 400, 800 or 1600 mg/head.day CIN treatments.

RESULTS

Inclusion of MO or CIN did not affect total saturated, unsaturated, polyunsaturated FA and individual FA in the various tissues with exceptions that proportion of palmitic acid in PCD muscle was increased by 800 mg/steer.day CIN (P < 0.05). There were positive correlations (P < 0.05) on oleic, linoleic, conjugated linoleic acid (CLA)-c9,t11 and 18:1-t10 between the subcutaneous fat and PCD muscle, and on α-linolenic acid, CLA-c9,t11 and 18:1-t10 between PCD muscle and liver, whereas correlations on the FA between the subcutaneous fat and liver were not significant except for 18:1-t10 (P < 0.01).

CONCLUSION

The results indicate that the supplementation of CIN and MO to feedlot diet has limited effect on beef FA profiles.

Impact of hard vs. soft wheat and monensin level on rumen acidosis in feedlot heifers

Many feedlot finishing diets include wheat when the relative wheat prices are low. This study was conducted to examine the responses in ruminal pH and fermentation as well as site and extent of digestion from substituting soft or hard wheat for barley grain and to determine whether an elevated monensin concentration might decrease indicators of ruminal acidosis in feedlot heifers. Five ruminally cannulated beef heifers were used in a 5 × 5 Latin square with 2 × 2 + 1 factorial arrangement. Treatments included barley (10% barley silage, 86% barley, 4% supplement, with 28 mg monensin/kg DM) and diets where barley was substituted by either soft or hard wheat with either 28 or 44 mg monensin/kg diet DM. Intake of DM was not affected by grain source, whereas increasing monensin with wheat diets reduced (P < 0.02) DMI. Mean ruminal pH was lower (P < 0.04) and durations of pH < 5.8 and pH < 5.5 greater (P < 0.03) for wheat than for barley diets. However, ruminal pH was not affected by wheat type or monensin level. Total VFA concentrations were greater (P < 0.03) for wheat than barley diets with no effect of wheat type. The molar proportion of propionate was greater (P < 0.04), whereas butyrate (P < 0.01) and ratio of acetate to propionate tended to be lower (P < 0.09), with the high as compared to low level of monensin. Replacing barley with wheat in finishing diets did not affect the duodenal flow or the digestibility of OM, likely as a result of greater (P < 0.01) NDF digestion from barley offsetting the increased (P < 0.03) supply of digested starch from wheat. Feeding soft vs. hard wheat delivered a greater (P < 0.03) duodenal supply of OM and nonammonia N with no differences in total tract nutrient digestion. The increased monensin concentration decreased the flow of OM (P < 0.01), total N (P < 0.05), and microbial protein (P < 0.05) to the small intestine due to decreased DMI. These results indicated that hard and soft wheat exhibited digestive characteristics similar to barley, but ruminal pH measurements indicate that compared with barley, wheat increased the risk of ruminal acidosis. Although an increased level of monensin had limited impact on ruminal indicators of acidosis, an increase in propionate would be expected to improve efficiency of feed use by heifers fed wheat-based finishing diets.

The effects of thyme and cinnamon essential oils on performance, rumen fermentation and blood metabolites in holstein calves consuming high concentrate diet

Essential oils have been shown to favorably effect in vitro ruminal fermentation, but there are few in vivo studies that have examined animal responses. The objective of this study was to evaluate the effects of thyme (THY) and cinnamon (CIN) essential oils on feed intake, growth performance, ruminal fermentation and blood metabolites in feedlot calves fed high-concentrate diets. Twelve growing Holstein calves (213±17 kg initial BW) were used in a completely randomized design and received their respective dietary treatments for 45 d. Treatments were: 1-control (no additive), 2-THY (5 g/d/calf) and 3-CIN (5 g/d/calf). Calves were fed ad libitum diets consisting of 15% forage and 85% concentrate, and adapted to the finishing diet by gradually increasing the concentrate ratio with feeding a series of transition diets 5 wk before the experiment started. Supplementation of THY or CIN did not affect DMI and ADG, and feed efficiency was similar between treatment groups. There were no effects of additives on ruminal pH and rumen concentrations of ammonia nitrogen and total VFA; whereas molar proportion of acetate and ratio of acetate to propionate decreased, and the molar proportion of propionate increased with THY and CIN supplementation. Rumen molar concentration of butyrate was significantly increased by adding CIN compared to control; but no change was observed with THY compared with control group. No effects of THY, or CIN were observed on valerate, isobutyrate or isovalerate proportions. Plasma concentrations of glucose, cholesterol, triglyceride, urea-N, β-hydroxybutyrate, alanine aminotransferase and aspartate aminotransferase were not changed by feeding THY or CIN. Results from this study suggest that supplementing a feedlot finishing diet with THY or CIN essential oil might be useful as ruminal fermentation modifiers in beef production systems, but has minor impacts on blood metabolites.

Effects of supplemental canola meal and various types of distillers grains on ruminal degradability, duodenal flow, and intestinal digestibility of protein and amino acids in backgrounded heifers

The objective of this study was to compare the diets with and without supplemental protein or protein sources on ruminal degradability, duodenal flows, and intestinal digestibility of protein and AA in growing heifers; supplemental protein included canola meal (CM) or dried distillers grains with solubles (DDGS) that varied in grain source and milling process. Five ruminally and duodenally cannulated Angus heifers (initial BW, 386 kg±20 kg) were assigned to a 5×5 Latin square with 21-d experimental periods. The diets consisted of 60% barley silage and 40% barley grain-based concentrate (DM basis) varying in protein source: CON (no protein supplement), CM, wheat DDGS (wDDGS), corn DDGS (cDDGS), or fractionated corn DDGS (fDDGS) plus urea N. Dietary CP concentrations were 11.9, 14.4, 14.4, 14.3, and 14.3% (DM basis), respectively, for CON-, CM-, wDDGS-, cDDGS-, and fDDGS-based diets. Intake of DM was less (P<0.02) for heifers fed CON than those fed protein-supplemented diets (PSD), which did not differ. Intake of N followed the same pattern as DMI with less (P<0.01) N intake by heifers fed CON than those fed PSD. Flows of OM, NDF, and starch to duodenum, and their digestibility in the rumen and in the total digestive tract did not differ among treatments. Flows of nonammonia N (NAN) and microbial N to the duodenum were greater (P<0.05) for heifers fed PSD than those fed CON. Furthermore, heifers fed fDDGS had greater (P<0.05) duodenal flow of NAN than those fed CM or cDDGS. Ruminal degradability of protein did not differ among diets, whereas digestibility of protein in the intestine was greater (P<0.04) for fDDGS than CON. Overall, flows of essential AA, nonessential AA, and total AA were greatest (P<0.05) for wDDGS and fDDGS, intermediate for CM and cDDGS, and least (P<0.01) for CON diets. Ruminal total VFA concentration was greater for wDDGS (P<0.01) and fDDGS (P<0.05) than CON and cDDGS with no differences in molar proportion of individual VFA. Ruminal NH3 N was greater for CM (P<0.01) and wDDGS (P<0.02) than CON, which was not different from cDDGS and fDDGS diets. These results indicate that wDDGS and fDDGS supplemented backgrounding diets delivered greater amounts of protein and AA at the small intestine compared to CM and cDDGS diets when formulated to be isonitrogenous. Supplemental protein increased the supply of protein and AA at the small intestine of cattle fed backgrounding diets comprised of barley silage and barley grain.

Effects of increasing levels of corn dried distillers grains with solubles and monensin on intake, digestion, and ruminal fermentation in beef heifers fed high-barley grain diets

The objective of this study was to determine whether increasing corn-based dried distillers grains with solubles (DDGS) in high-barley grain diets reduces the merit of using higher levels of monensin by assessing intake, digestibility, and ruminal pH and fermentation in feedlot heifers. Five ruminally and duodenally cannulated Angus heifers (average BW of 599±36 kg) were used in a 5×5 Latin square with a 2×2+1 factorial arrangement. Treatments were control (CON, 10% barley silage, 90% barley-based concentrate, and 28 mg monensin/kg DM) and diets substituting 20% (LDG) or 40% (HDG) DDGS for barley grain with 28 mg (ML) or 48 mg (MH) monensin/kg diet DM: 1) CONML, 2) LDGML, 3) HDGML, 4) LDGMH, and 5) HDGMH. Contrasts compared LDG vs. HDG, ML vs. MH, interactions between DDGS and monensin, and the effect of increasing DDGS in the diet. Increasing DDGS quadratically (P<0.01) increased DMI. There was no interaction for DMI between the dietary inclusion rate of DDGS and the dose of monensin; however, DMI was reduced (P<0.05) for heifers fed MH vs. ML. Ruminal digestibility of OM, NDF, and starch linearly decreased (P<0.01), but intestinal digestibility linearly increased (P<0.01) with increasing DDGS, resulting in no differences in total tract digestibility. Ruminal digestibility of OM was greater (P<0.04) in heifers fed MH than ML; however, the total tract digestibility of OM was not affected. Intake of N, flows of total N, nonammonia N, and dietary N were linearly (P<0.02) increased, and the efficiency of ruminal microbial synthesis linearly (P<0.04) improved with increasing DDGS. Increasing DDGS inclusion linearly decreased (P<0.04) the acetate to propionate ratio. Inclusion of MH decreased (P<0.04) acetate and increased (P<0.05) NH3-N compared to ML, but high monensin did not affect mean ruminal pH, the duration of pH<5.8, 5.5, 5.2, or the area below the curve at pH 5.8, 5.5, and 5.2, indicating that there was no evidence that it modulated ruminal pH. These results suggest that feeding monensin at 48 vs. 28 mg/kg diet DM altered nutrient availability and site of feed digestion, likely as a result of reduced DMI and increased ruminal digestion of DM. High levels of monensin may reduce the risk of acidosis through a reduction in DMI, but in the present study this was not evident in differences in the ruminal pH profiles between heifers fed ML and MH diets.

The influence of diet type (dairy versus intensive fattening) on the effectiveness of garlic oil and cinnamaldehyde to manipulate in vitro ruminal fermentation and methane production

The objective of this study was to evaluate the effects of increasing doses [0 (control: CON), 20, 60, 180 and 540 mg/L incubation medium] of garlic oil (GO) and cinnamaldehyde (CIN) on in vitro ruminal fermentation of two diets. Batch cultures of mixed ruminal microorganisms were inoculated with ruminal fluid from four sheep fed a medium-concentrate diet (MC; 50 : 50 alfalfa hay : concentrate) or four sheep fed a high-concentrate diet (HC; 15 : 85 barley straw : concentrate). Diets MC and HC were representative of those fed to dairy and fattening ruminants, respectively. Samples of each diet were used as incubation substrates for the corresponding inoculum, and the incubation was repeated on 4 different days (four replicates per experimental treatment). There were GO × diet-type and CIN × diet-type interactions (P < 0.001–0.05) for many of the parameters determined, indicating different effects of both oils depending on the diet type. In general, effects of GO were more pronounced for MC compared with HC diet. Supplementation of GO did not affect (P > 0.05) total volatile fatty acid (VFA) production at any dose. For MC diet, GO at 60, 180 and 540 mg/L decreased (P < 0.05) molar proportion of acetate (608, 569 and 547 mmol/mol total VFA, respectively), and increased (P < 0.05) propionate proportion (233, 256 and 268 mmol/mol total VFA, respectively), compared with CON values (629 and 215 mmol/mol total VFA for acetate and propionate, respectively). A minimum dose of 180 mg of GO/L was required to produce similar modifications in acetate and propionate proportions with HC diet, but no effects (P > 0.05) on butyrate proportion were detected. Methane/VFA ratio was reduced (P < 0.05) by GO at 60, 180 and 540 mg/L for MC diet (0.23, 0.16 and 0.10 mol/mol, respectively), and by GO at 20, 60, 180 and 540 mg/L for HC diet (0.19, 0.19, 0.16 and 0.08 mol/mol, respectively), compared with CON (0.26 and 0.21 mol/mol for MC and HC diets, respectively). No effects (P = 0.16–0.85) of GO on final pH and concentrations of NH3-N and lactate were detected. For both diet types, the highest CIN dose decreased (P < 0.05) production of total VFA, gas and methane, which would indicate an inhibition of fermentation. Compared with CON, CIN at 180 mg/L increased (P < 0.05) acetate proportion for the MC (629 and 644 mmol/mol total VFA for CON and CIN, respectively) and HC (525 and 540 mmol/mol total VFA, respectively) diets, without affecting the proportions of any other VFA or total VFA production. Whereas for MC diet CIN at 60 and 180 mg/L decreased (P < 0.05) NH3-N concentrations compared with CON, only a trend (P < 0.10) was observed for CIN at 180 mg/L with the HC diet. Supplementation of CIN up to 180 mg/L did not affect (P = 0.18–0.99) lactate concentrations and production of gas and methane for any diet. The results show that effectiveness of GO and CIN to modify ruminal fermentation may depend on diet type, which would have practical implications if they are confirmed in vivo.

Effects of wheat dried distillers' grains with solubles and cinnamaldehyde on in vitro fermentation and protein degradation using the Rusitec technique

This study was conducted to evaluate the effect of wheat dried distillers' grains with solubles (DDGS) and cinnamaldehyde (CIN) on in vitro fermentation and microbial profiles using the rumen simulation technique. The control substrate (10% barley silage, 85% barley grain and 5% supplement, on dry matter basis) and the wheat DDGS substrate (30% wheat DDGS replaced an equal portion of barley grain) were combined with 0 and 300 mg CIN/l of culture fluid. The inclusion of DDGS increased (p < 0.05) the concentration of volatile fatty acids (VFA) and the molar proportion of acetate and propionate. Dry matter disappearance (p = 0.03) and production of bacterial protein (p < 0.01) were greater, whereas the disappearances of crude protein (CP) and neutral detergent fibre were less (p < 0.01) for the DDGS than for the control substrate. With addition of CIN, concentration of total VFA decreased and fermentation pattern changed to greater acetate and less propionate proportions (p < 0.01). The CIN reduced (p < 0.01) methane production and CP degradability. The copy numbers of Fibrobacter, Prevotella and Archaea were not affected by DDGS but were reduced (p < 0.05) by CIN. The results indicate that replacing barley grain by DDGS increased nutrient fermentability and potentially increase protein flows to the intestine. Supplementation of high-grain substrates with CIN reduced methane production and potentially increased the true protein reaching the small intestine; however, overall reduction of feed fermentation may lower the feeding value of a high-grain diet.