Use of 'natural' products as alternatives to antibiotic feed additives in ruminant production

Turmeric rhizomes reduced in vitro methane production and improved gas production and nutrient degradability

The present study aimed to evaluate the effect of dry turmeric rhizomes on in vitro biogas production and diet fermentability. Turmeric rhizomes were included at gradually increased levels: 0, 0.5, 1, 1.5 and 2% of a diet containing per kg dr matter (DM): 500 g concentrate feed mixture, 400 g berseem hay and 100 g rice straw, and incubated for 48 h. Gas chromatography-mass spectrometry analysis showed that ar-turmerone, α-turmerone and β-turmerone were the major bioactive compounds in the rhizomes. Turmeric rhizomes increased (p < 0.01) asymptotic gas production (GP) and rate and lag of CH4 production and decreased (p < 0.01) rate of GP, lag of GP, asymptotic CH4 production and proportion of CH4 production. Turmeric rhizome administration linearly increased (p < 0.01) DM and fiber degradability and concentrations of total short-chain fatty acids, acetic and propionic acids and ammonia-N and quadratically (p < 0.05) decreased fermentation pH. It is concluded that including up to 2% turmeric rhizomes improved in vitro ruminal fermentation and decreased CH4 production.

Effects of Centella asiatica Extracts on Rumen In Vitro Fermentation Characteristics and Digestibility

Two in vitro experiments were conducted to evaluate the effects of Centella asiatica extract (CAE) supplementation on the rumen's in vitro fermentation characteristics. In the first experiment, CAE with five concentrations (C: 0%; T1: 3.05%; T2: 6.1%; T3: 12.2%; and T4: 24.4% CAE in diet) was supplemented in the rumen fluid and incubated for 6, 24, and 48 h to determine the optimal dosage. The total gas and methane production increased in all incubation times, and the total volatile fatty acids increased at 6 and 48 h. Ammonia nitrogen, branched chain volatile fatty acids, acetate, and butyrate were increased by CAE supplementation. T1 was chosen as the optimal dosage based on the total volatile fatty acids, branched chain volatile fatty acids, and ammonia nitrogen production. The CAE with the identified optimal dosage (T1) was incubated to identify its effect on the rumen's in vitro degradability in the second experiment. The CAE supplementation did not influence the in vitro dry matter, crude protein, or neutral detergent fiber degradability. In conclusion, CAE has no CH4 abatement or digestion promotion effects. However, CAE could be utilized as a feed additive to increase the rumen's total volatile fatty acid production without an adverse effect on the in vitro dry matter, crude protein, or neutral detergent fiber degradability.

Impacts of thyme and/or garlic oils on growth, immunity, antioxidant and net farm income in Damascus goats

This study aimed to evaluate the impact of thyme and/or garlic oil administration on growth performance, immunity, antioxidant, biochemical parameters, and net farm income of Damascus goats. Forty weaned Damascus goats were allocated into four groups. The first group was the control without oral administration, while the 2nd (Th), 3rd (Gr), and 4th (ThGr) groups were orally administrated by (2 ml/goat/day) of thyme oil, garlic oil and their mixture (1:1), respectively during the whole experiment period. The final body weight of goats orally administered oil mixture was the heaviest group, it was 10, 4.5 and 3.5% than the control, Th. and Gr. groups, respectively with better feed conversion ratio and high net farm income. Goats of ThGr. group revealed the best immunity, antioxidant and general health condition than the control group with 50% reduction of MDA. Liver (AST, 33% and ALT, 38%) and kidney (creatinine, 88%) functions improved by oils mixtures orally administration compared with the control group. LDL, triglyceride and cholesterol were reduced by 47, 33 and 21% compared with the control group, respectively. Thus, mixture oil administration (thyme and garlic at the ratio of 1:1, 2 ml/goat/day) improved growth (10%), antioxidant status (MDA 50%), liver (AST, 33% and ALT, 38%), kidney function (creatinine, 88%), the FCR (17.4%) and net farm income (21%), of Damascus goats.

The Effect of Saponite Clay on Ruminal Fermentation Parameters during In Vitro Studies

Reducing the emission of global warming gases currently remains one of the strategic tasks. Therefore, the objective of our work was to determine the effect of saponite clay on fermentation in the rumen of cows. The pH, total gas production, CH4, and volatile fatty acid (VFA) production in ruminal fluid was determined in vitro. Saponite clay from the Tashkiv deposit (Ukraine) has a high content of silicon, iron, aluminum, and magnesium. The addition of 0.15 and 0.25 g of saponite clay to the incubated mixture did not change the pH but reduced the total production (19% and 31%, respectively) and CH4 (24% and 46%, respectively) in the ruminal fluid compared to the control group and had no significant effect on the total VFA levels, but propionic acid increased by 15% and 21% and butyric acid decreased by 39% and 32%, respectively. We observed a decrease in the fermentation rates, with a simultaneous increase in the P:B ratio and an increase in the fermentation efficiency (FE) in the groups fermented with saponite clay, probably a consequence of the high efficiency in the breakdown of starch in the rumen. Therefore, further in vivo studies to determine the effective dose and effect of saponite clay on cow productivity and the reduction of gas emissions are promising and important.

Effect of Dietary Supplementation of Chestnut and Quebracho Tannin Supplementation on Neonatal Diarrhoea in Preweaning Calves

Neonatal calf diarrhoea (NCD) poses a significant health challenge in cattle herds, resulting in considerable economic losses and antimicrobial use. In response to the escalating threat of antimicrobial resistance, viable alternatives are imperative, aligning with European policies. This study evaluated the in-milk supplementation of the chestnut and quebracho tannin extract in preweaning calves on performance, diarrhoea occurrence, Cryptosporidium spp. shedding, protein digestibility, and intestinal health. Twenty newborn calves were divided, after colostrum administration, into two experimental groups for 30 days as follows: the control (CTRL) was fed with whole milk and solid feed, and tannins (TAN) were fed whole milk supplemented with 6/g day of tannin extract and solid feed. Faecal samples were collected on days 0, 3, 7, 14, and 30 for the evaluation of Cryptosporidium oocyst shedding and protein digestibility. Faecal consistency was evaluated during the sampling using the faecal score scale (0-3 scale, considering diarrhoea > 1). The results showed a significant reduction in diarrhoea frequency in the TAN compared to the CTRL group (p < 0.05) over 30 days of the trial. The prevalence of Cryptosporidium spp. was generally low (12%), considering all analysed samples. Protein digestibility revealed comparable values for the TAN and CTRL groups, suggesting that tannins did not negatively affect milk protein availability. In conclusion, the in-milk supplementation of 6/g day of the chestnut and quebracho tannin extract could be considered a valuable functional feed additive to decrease NCD occurrence, thus supporting animal health and decreasing antibiotic use in livestock.

Fennel seeds dietary inclusion as a sustainable approach to reduce methane production and improve nutrient utilization and ruminal fermentation

Ruminants are considered a major producer of methane (CH4 ). Therefore, the present study aimed to determine the ability of dry fennel seeds to affect in vitro gas production and fermentation. Fennel seeds were included at 0% (Control), 0.5%, 1%, 1.5%, and 2% DM of a diet containing per kg DM: 500 g concentrate feed mixture, 400 g berseem hay, and 100 g of rice straw. The incubations lasted 48 h. Fennel seeds increased (P < 0.001) the asymptotic gas production and decreased its rate, while decreasing the production and proportion of CH4 (P < 0.05) and increased its rate. Moreover, fennel seed increased DM and neutral detergent fiber (P < 0.01) degradability, and increased total production of short-chain fatty acids, acetate, and propionate (P < 0.05). Compared to the control, fennel seeds increased (P < 0.01) metabolizable energy, partitioning factor, and microbial crude protein production. Overall, fennel seeds can be included up to 2% DM in ruminant diets as an environmentally friendly product in animal farming due to its ability to improve feed utilization, ruminal fermentation and while reducing CH4 production.

Nutritional impact of nano zeolite, probiotic, and fatty acids as feed additives on health status of Nile tilapia (Oreochromis niloticus)

For human consumption, fish is a good and affordable source of several crucial elements. Growing aquaculture management and output is always necessary. Therefore, this study was designed to evaluate the effect of probiotics, nano zeolite, and/or medium chain fatty acids (MCFA) on fish health and the chemical composition of the fish body. The experimental fish were distributed into eight groups. T1: Control group fed the basal diet without feed additives, T2: Nano zeolite at a rate of 2 mg/kg diet, T3: Pedococcus at a rate of 2 gm kg diet, T4: Medium chain fatty acids used according to produced company recommendation at a rate of 3.5 gm/kg diet, T5: Nano zeolite (2 mg/kg diet) + Pedococcus (2 mg/kg diet), T6: Nano zeolite (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet), T7: Pedococcus (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet), and T8: Nano zeolite (2 mg/kg diet) + Pedococcus (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet). The obtained results showed an insignificant difference in the body composition of Nile tilapia fish fed feed additives alone or in combination. Moreover, the feed additives did not affect the health status of fish, as indicated by normal liver and kidney functions.

Assessing the In Vitro and In Vivo Effect of Supplementation with a Garlic (Allium sativum) and Oregano (Origanum vulgare) Essential Oil Mixture on Digestibility in West African Sheep

This study assessed the impact of a mixture of garlic (Allium sativum) and oregano (Origanum vulgare) essential oils (EOGOs) on in vitro dry matter digestibility (IVDMD) and in vivo apparent nutrient digestibility. Different EOGO inclusion levels were evaluated to assess the dose response and potential effects of the mixture. Three EOGO inclusion levels (0.5, 0.75, and 1 mL/kg of incubated dry matter) were evaluated in vitro, while four treatments (0.5, 0.75, and 1 mL/day of EOGO and a control group) were tested in vivo on 12 West African sheep. A randomized controlled trial was conducted using a 4 × 4 design. Blood parameters (glucose, blood urea nitrogen, and β-hydroxybutyrate) were measured to observe the effect of EOGO on the metabolism. The results showed that the inclusion of EOGO significantly enhanced IVDMD at low levels (p < 0.052) compared with the highest levels in treatments containing 0.5 and 0.75 mL/kg of EOGO dry matter. A higher intake of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) (p < 0.05) was observed in the in vivo diets with the inclusion of EOGO. In terms of in vivo apparent digestibility, significant differences were found among treatments in the digestibility coefficients of DM, CP, and NDF. EOGO inclusion increased the digestibility of DM. CP digestibility displayed a cubic effect (p < 0.038), with the lowest values of digestibility observed at 1 mL EOGO inclusion. Additionally, NDF digestibility showed a cubic effect (p < 0.012), with the highest value obtained at 0.75 mL of EOGO inclusion. The inclusion levels above 0.75 mL EOGO showed a cubic effect, which indicates that higher concentrations of EOGO may not be beneficial for the digestibility of CP and NDF. Although no significant difference was observed in total digestible nutrients, a linear trend was observed (p < 0.059). EOGO improved the intake of DM, CP, and NDF. EOGO supplementation improved the digestibility of DM and NDF, with optimal levels observed at 0.5 mL/day. No significant effects were observed in the blood parameters. These results suggest that EOGO has the potential as an additive in ruminal nutrition to improve food digestibility and serve as an alternative to antibiotic additives. The use of EOGO potentially improves fiber digestion and may reduce the use of antibiotics in livestock production. Garlic (A. sativum) and oregano (O. vulgare) essential oils effectively modulated fiber digestibility at 0.75 mL/day. Garlic (A. sativum) and oregano (O. vulgare) essential oils have the potential to improve digestibility at low inclusion levels and serve as an alternative to antibiotic additives. The effectiveness of essential oils is greater in a mixture and at lower doses.

Effects of dietary feed supplementation with heat-treated Lactobacillus sakei HS-1 on the health status, blood parameters, and fecal microbes of Japanese Black calves before weaning

Background and Aim

Our previous research suggested that heat-killed Lactobacillus sakei HS-1 (HK-LS HS-1) is potentially beneficial for improving intestinal microbes and reducing the number of medical treatments. This study aimed to investigate the effect of HK-LS HS-1 as a supplement in milk replacers (MRs) on clinical health during the 1-month preweaning period.

Materials and Methods

Eighteen female calves were randomly assigned to either a group receiving the HK-LS HS-1 supplement (n = 9) or a control group without it (n = 9). We then investigated the effect of including supplementary HK-LS HS-1; 0.2% in MRs twice daily at 09:00 and 16:00 on the health, serum biochemical parameters (measured using an automated biochemical analyzer), and fecal bacteriological changes of preweaning Japanese Black calves at the day of the start of supplementation (before HK-LS HS-1 supplementation; day 0), at weaning (day 30), and at 2 weeks (day 45) and 4 weeks (day 60) after weaning.

Results

During the supplementation period (0-30 days), (1) an increase (p = 0.023) was observed in albumin, and there was a tendency of increase in total cholesterol level in the HK-LS HS-1 group but not in the control group; (2) substantial differences were obtained after the weaning period (30-60 days), although no differences were observed from 0-30 days in both groups. The anti-Müllerian hormone (AMH) level was substantially increased after weaning in the control group. No differences were observed in the amounts of Coliform spp. and Staphylococcaceae spp. between the two groups; thus, HK-LS HS-1 supplementation had similar antibacterial effects. A significant reduction was observed in the time to weaning of the HK-LS HS-1 group in the field trial.

Conclusion

Supplementation with HK-LS HS-1 from an early stage after birth to weaning is a cost-effective treatment to improve the growth rate of preweaning calves. However, supplementation during only preweaning periods appears to have no beneficial effects on preventing weaning stress, especially in terms of AMH levels.

Essential oil blend supplementation in the milk replacer of dairy calves: Performance and health

Supplementation of dairy calves with essential oils in the liquid diet can reduce the incidence and severity of infectious diseases and promote better performance. Our objective was to evaluate an essential oil blend containing peppermint, eucalyptus, and menthol crystals and its effect on performance and health during the pre and postweaning period of dairy calves. At birth, 40 dairy calves (34 males and 6 females) were blocked according to sex and birth weight, randomly assigned to one of two treatments-commercial milk replacer diluted at 14% (MR) and the same liquid diet plus essential oil blend (MREO) at a dose of 4 mL per calf per day, divided into two meals during the first 28 days of life. Calves were individually housed and fed 6 L/d of the liquid diet, divided into two meals, and received starter concentrate and water ad libitum. Weaning was gradually reduced by 1L per day at d 51 until complete weaning at 56 days. After weaning, calves were evaluated until 70 days of age, when the experimental period ended. Intake, fecal, and health scores were evaluated daily, weight and body measures were recorded weekly, and blood parameters were evaluated at weeks 1, 2, 3, 4, and 8. Calves fed MREO tended to have higher total dry matter intake during the preweaning period. Furthermore, MREO calves had lower health scores and fewer days with a health score ≥ 4 (suggestive of bronchopneumonia), tended to lower coughing days and fewer veterinary interventions preweaning, and tended to lower health scores postweaning. The supplementation with a blend of essential oils containing peppermint, eucalyptus, and menthol crystals can reduce respiratory problems. Further studies are needed to investigate the dose and the supplementation period.

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 Chitosan on Ruminal Fermentation and Microbial Communities, Methane Emissions, and Productive Performance of Dairy Cattle

This study aimed to expand the knowledge about the activity and mode of action of CHI on methanogenesis and rumen microbial populations in vivo. A total of 16 lactating dairy cows were distributed in two groups, one of them receiving 135 mg CHI/kg body weight daily. The effect on productive performance, milk composition, fermentation efficiency, methane emissions, microbial protein synthesis, and ruminal microbial communities was determined. Supplementation with CHI did not affect rumen microbial diversity but increased the relative abundance (RA) of the bacteria Anaeroplasma and decreased those of rumen ciliates and protozoa resulting in a shift towards a lower acetic to propionic ratio. However, no effect on milk yield or methane intensity was observed. In conclusion, supplementing 135 mg CHI/kg body weight increased the RA of Anaeroplasma and decreased those of rumen ciliates and protozoa, both being related to fiber degradation in the rumen in different ways and resulted in a shift of ruminal fermentation towards more propionate proportions, without affecting CH4 emissions, milk yield, or milk composition. Further research with higher doses would be necessary to assess the potential use of this additive as a methane inhibitor.

Curcumin and curcumin nanoparticles counteract the biological and managemental stressors in poultry production: An updated review

Antibiotics have the potential to have both direct and indirect detrimental impacts on animal and human health. For instance, antibiotic residues and pathogenic resistance against the drug are very common in poultry because of antibiotics used in their feed. It is necessary to use natural feed additives as effective alternatives instead of synthetic antibiotics. Curcumin, a polyphenol compound one of the natural compounds from the rhizomes of turmeric (Curcuma spp.) and has been suggested to have several therapeutic benefits in the treatment of human diseases. Curcumin exhibited some positive responses such as growth promoter, antioxidant, antibacterial, antiviral, anticoccidial, anti-stress, and immune modulator activities. Curcumin played a pivotal role in regulating the structure of the intestinal microbiome for health promotion and the treatment of intestinal dysbiosis. It is suggested that curcumin alone or a combination with other feed additives could be a dietary strategy to improve poultry health and productivity.

Dietary Ruminant Enteric Methane Mitigation Strategies: Current Findings, Potential Risks and Applicability

This review examines the current state of knowledge regarding the effectiveness of different dietary ruminant enteric methane mitigation strategies and their modes of action together with the issues discussed regarding the potential harms/risks and applicability of such strategies. By investigating these strategies, we can enhance our understanding of the mechanisms by which they influence methane production and identify promising approaches for sustainable mitigation of methane emissions. Out of all nutritional strategies, the use of 3-nitrooxypropanol, red seaweed, tannins, saponins, essential oils, nitrates, and sulfates demonstrates the potential to reduce emissions and receives a lot of attention from the scientific community. The use of certain additives as pure compounds is challenging under certain conditions, such as pasture-based systems, so the potential use of forages with sufficient amounts of plant secondary metabolites is also explored. Additionally, improved forage quality (maturity and nutrient composition) might help to further reduce emissions. Red seaweed, although proven to be very effective in reducing emissions, raises some questions regarding the volatility of the main active compound, bromoform, and challenges regarding the cultivation of the seaweed. Other relatively new methods of mitigation, such as the use of cyanogenic glycosides, are also discussed in this article. Together with nitrates, cyanogenic glycosides pose serious risks to animal health, but research has proven their efficacy and safety when control measures are taken. Furthermore, the risks of nitrate use can be minimized by using probiotics. Some of the discussed strategies, namely monensin or halogenated hydrocarbons (as pure compounds), demonstrate efficacy but are unlikely to be implemented widely because of legal restrictions.

Measurement of serum short-chain fatty acid concentrations in cattle after oral administration of difructose anhydride III

Background and Aim

We previously reported the mitigation effects of difructose anhydride III (DFA III) on mycotoxins, such as zearalenon and sterigmatocystin, based on the urinary concentrations of these molecules in calves. This study was aimed at evaluating the effects of dietary supplementation of DFA III and the fermented status of DFA III in the intestine by comparing serum levels of short-chain fatty acid (SCFAs) in DFA III-supplemented cattle with those in non-supplemented control cattle.

Materials and Methods

Serum SCFA concentrations were measured in 30 Japanese Black heifers, aged 9-10 months, from two herds, using gas chromatography on days 0 (before DFA III supplementation), 9, and 14 after DFA III supplementation.

Results

A notably different trend was observed for isobutyric acid and enanthic acid, which may reflect the different fermentation status of supplementary DFA III in the intestine. Our results indicate the possibility that this trend observed in the intestinal tract following DFA III administration is associated with changes in the environment of intestinal bacterial flora, which may partially reflect the effects of DFA III supplementation on cattle.

Conclusion

Difructose anhydride III supplementation for at least 2 weeks affects the trend of blood SCFA concentrations in cattle. Our results provide evidence supporting the effects of DFA III on the intestinal environment and intestinal barrier function.

Bee venom as an alternative for antibiotics against Staphylococcus aureus infections

The misuse of antibiotics has led to antibiotic-resistant bacterial strains, making it even harder to combat and eliminate their infections. Staphylococcus aureus causes various adverse infections and diseases, including skin abscesses, bloodstream infections, pneumonia, and joint infections. In this study, we aimed to test the cytotoxic and antibacterial effects of bee venom-loaded chitosan nanoparticles (BV-loaded CS-NPs) in comparison to gamma-irradiated BV and native BV from Apis mellifera. The physiochemical characterizations of our treatments were determined by Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscope (TEM), zeta-potential, release rate, and Encapsulation Efficiency (EE). Our study was conducted on both levels, in-vitro and in-vivo. For the in-vitro study, a bacterial model of Staphylococcus aureus with an ATCC number of 6538 was grown in tryptic soy agar (TSA) medium, and the inhibition zones of our drug candidates were measured with the appropriate statistical analysis performed. For the in-vivo study, levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), Creatinine, Urea, and interleukin 6 (IL-6) were analyzed. BV-loaded CS-NPs showed relatively better results than the other alternatives, which are native BV and gamma-irradiated BV. The results showed that the antibacterial effect of BV-loaded CS-NPs was greater than the alternatives. Furthermore, its cytotoxic effect was far less than the native and irradiated bee venom. These outcomes ensure that loading BV on CS-NPs makes it a promising drug candidate for an antibiotic alternative with minimal cytotoxicity and enhanced antibacterial activity.

Effect of propionate, monensin, and saccharomyces cerevisiae or their combination on production and rumen fermentation of holstein steers

This study aimed to evaluate the effects of calcium propionate (PrCa), PrCa + monensin sodium (PrCa + Mon), and PrCa + Saccharomyces cerevisiae (PrCa + Sc) on the productive performance of Holstein steers. Twenty-four Holstein steers (270.0 ± 25.85 kg) were distributed individually into four treatments of six replicates. The treatments were control (no additives), PrCa (10 g/kg), PrCa + Mon (10 g/kg + 30 mg/kg), and PrCa + Sc (10 g/kg + 12.8 × 10⁹ cfu). The steers were fed for 43 days, and afterwards, nutrient intake and digestibility as well as volatile fatty acids were determined, while the weight gained, feed efficiency, and CH₄ production were calculated. Diet of PrCa + Sc had the highest (P < 0.0001) acid detergent fiber intake and propionate acid as well as the nutrient digestibility, with lowest (P < 0.0001) rumen acetic acid, methane, and protozoa concentration versus other diets. In conclusion, dietary inclusion of PrCa + Sc (10 g/kg + 12.8 × 10⁹ cfu) improved nutrient digestibility, rumen fermentation, and reduced methane emission, thereby enhancing the possibility of ecofriendly ruminant farming.

Effects of Thymbra capitata essential oil on in vitro fermentation end-products and ruminal bacterial communities

An in vitro trial was carried out to investigate the effects of natural Thymbra capitata essential oil (NEO) and its main compounds [including carvacrol, p-cymene, γ-terpinene given alone or in a synthetic combination (SEO)] on ruminal fermentation and the bacterial community using batch cultures inoculated with ruminal digesta and incubating two different basal diets [high-forage (F) and high-concentrate (C) diet]. After 24 h of incubation, primary fermentation end-products [gas, methane, volatile fatty acids (VFAs) and ammonia] and rumen microbial diversity were determined. NEO reduced the total VFA concentration (P < 0.05) only in the C diet. In contrast, SEO and carvacrol decreased the total VFA concentration (P < 0.05) only in the F diet. Methane production was not affected (P > 0.05) by any of the experimental treatments or diets evaluated. Microbial diversity analysis showed only a moderate effect of carvacrol and SEO on 13 genera, including, mainly, Atopobium and Blautia (involved in subacute ruminal acidosis) or Candidatus Saccharimonas (related to laminitis). In conclusion, T. capitata EO has a limited potential to attain nutritional or environmental benefits, but further research should be carried out to clarify its effects on animal health and microbial food safety.

Microbial Fermented Liquid Supplementation Improves Nutrient Digestibility, Feed Intake, and Milk Production in Lactating Dairy Cows Fed Total Mixed Ration

The purpose of this experiment was to examine the effects of MFL supplementation on feed intake, nutrient digestibility, milk yield, and milk composition in early lactating dairy cows. Twelve, Thai crossbred Holstein Friesian cows in early lactation, 500 ± 30 kg of body weight (BW), were randomly assigned according to a completely randomized design (CRD). MFL supplementation levels of 0, 100, 200, and 300 mL/d were used as treatments. Experimental animals were fed a total mixed ration (TMR) with a roughage to concentrate ratio (R:C ratio) of 40:60, which contains 12% crude protein (CP) and 70% total digestible nutrient (TDN). Rice straw was a roughage source. MFL supplementation levels had no effect (p > 0.05) on body weight change and dry matter intake (DMI) expressed as %BW, whereas DMI expressed as metabolic body weight (BW^0.75) was linearly (p < 0.05) increased, with the highest at 200 mL/d in the YFL supplementation group (147.5 g/kg BW^0.75), whereas feed intake of organic matter (OM), CP, ether extract (EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) did not significant (p > 0.05) difference among treatments. Related to apparent digestibility, MFL levels did not affect (p > 0.05) on DM, OM, and EE digestibility, while apparent digestibility of CP, NDF, and ADF were linearly increased (p < 0.05) when increasing MFL supplementation levels, and the highest (p < 0.05) were the 200 and 300 mL/d FML supplemented groups. BUN at 0 h post feeding did not show a significant difference (p > 0.05) between treatments, while at 4 h after feeding, BUN was linearly (p < 0.05) increased from 0, 100, 200, and 300 (mL/day) MFL supplementation, the values were 12.9, 13.1, 19.7, and 18.4 mg/dL, respectively and the highest was 200 mL/head/day for the MFL supplemented group. MFL supplementation did not affect (p > 0.05) milk fat, lactose, solid not fat (SNF), and specific gravity of milk, while MFL supplementation at 200 mL/day caused a linear increase (p < 0.01) in BUN, MUN, milk yield, milk protein, total solids (TS) and 3.5% FCM when supplement levels were increased. In conclusion, MFL supplementation in early lactating dairy cows could improve feed intake, nutrient digestibility, milk yield, and milk composition.

The impact of curcumin on livestock and poultry animal's performance and management of insect pests

Plant-based natural products are alternative to antibiotics that can be employed as growth promoters in livestock and poultry production and attractive alternatives to synthetic chemical insecticides for insect pest management. Curcumin is a natural polyphenol compound from the rhizomes of turmeric (Curcuma spp.) and has been suggested to have a number of therapeutic benefits in the treatment of human diseases. It is also credited for its nutritional and pesticide properties improving livestock and poultry production performances and controlling insect pests. Recent studies reported that curcumin is an excellent feed additive contributing to poultry and livestock animal growth and disease resistance. Also, they detailed the curcumin's growth-inhibiting and insecticidal activity for reducing agricultural insect pests and insect vector-borne human diseases. This review aims to highlight the role of curcumin in increasing the growth and development of poultry and livestock animals and in controlling insect pests. We also discuss the challenges and knowledge gaps concerning curcumin use and commercialization as a feed additive and insect repellent.

Dietary Polysaccharide-Rich Extract from Noni (Morinda citrifolia L.) Fruit Modified Ruminal Fermentation, Ruminal Bacterial Community and Nutrient Digestion in Cashmere Goats

In two consecutive studies, we evaluated the effects of polysaccharide-rich noni (Morinda citrifolia L.) fruit extract (NFP) on ruminal fermentation, ruminal microbes and nutrient digestion in cashmere goats. In Exp. 1, the effects of a diet containing NFP of 0, 0.1%, 0.2%, 0.4% and 0.55% on in vitro ruminal fermentation at 3, 6, 9, 12 and 24 h were determined, whereas in Exp. 2, fourteen cashmere goats (46.65 ± 3.36 kg of BW ± SD) were randomly assigned to two treatments: the basal diet with or without (CON) supplementation of NFP at 4 g per kg DM (0.4%). The in vitro results showed that NFP linearly increased concentrations of volatile fatty acids (VFA), quadratically decreased ammonia-N concentration, and changed pH, protozoa number, gas production and the microbial protein (MCP) concentration, and was more effective at 0.4% addition, which yielded similar results in ruminal fermentation in Exp. 2. In addition, NFP increased the apparent digestibility of dry matter and crude protein and the abundance of Firmicutes, and reduced the abundance of Bacteroides and Actinobacteria. Ruminococcus_1 was positively associated with VFA concentration. The Rikenellaceae_RC9_gut_group was positively correlated with protozoa and negatively correlated with MCP concentration. Thus, NFP has potential as a ruminal fermentation enhancer for cashmere goats.

Effects of rutin supplementation on growth performance, slaughter performance, serum parameters, and meat quality of Nubian goats

Previous studies found that rutin can improve production performance of sheep and dairy cows. However, it is not clear whether rutin has similar effects in goats. Hence, the aim of this experiment was to study the effects of rutin supplementation on growth performance, slaughter performance, serum parameters, and meat quality of Nubian goats. A total of 36 healthy Nubian ewes were randomly divided into three groups. Goats were fed the basal diet supplemented with 0 (R0), 25 (R25), and 50 (R50) mg rutin per kg of diet. The growth performance and slaughter performance of goats had no significant difference among three groups. The meat pH45min and moisture were significantly higher in the R25 group than the R50 group (p < 0.05), but the color value b* and contents of C14:0, C16:0, C18:0, C18:1n9c, C20:1, saturated fatty acid (SFA), and monounsaturated fatty acid (MSFA) in meat had an opposite outcome. The dressing percentage had an increasing tendency in the R25 group compared with the R0 group (0.05 < p < 0.10), but the shear force, water loss rate and crude protein of meat had opposite results. In conclusion, rutin could not affect the growth performance and slaughter performance of goats; low levels could possibly improve meat quality.

Garlic and Its Bioactive Compounds: Implications for Methane Emissions and Ruminant Nutrition

Methane (CH4) emission from enteric fermentation of ruminant livestock is a source of greenhouse gases (GHG) and has become a significant concern for global warming. Enteric methane emission is also associated with poor feed efficiency. Therefore, research has focused on identifying dietary mitigation strategies to decrease CH4 emissions from ruminants. In recent years, plant-derived bioactive compounds have been investigated for their potential to reduce CH4 emissions from ruminant livestock. The organosulphur compounds of garlic have been observed to decrease CH4 emission and increase propionate concentration in anaerobic fermentations (in vitro) and in the rumen (in vivo). However, the mode of action of CH4 reduction is not completely clear, and the response in vivo is inconsistent. It might be affected by variations in the concentration and effect of individual substances in garlic. The composition of the diet that is being fed to the animal may also contribute to these differences. This review provides a summary of the effect of garlic and its bioactive compounds on CH4 emissions by ruminants. Additionally, this review aims to provide insight into garlic and its bioactive compounds in terms of enteric CH4 mitigation efficacy, consistency in afficacy, possible mode of action, and safety deriving data from both in vivo and in vitro studies.

Potential of selected plant extracts to control severe subacute ruminal acidosis in vitro as compared with monensin

Background

In recent years, researchers have become increasingly interested in developing natural feed additives that can stabilize ruminal pH and thus prevent or eliminate the risk of severe subacute rumen acidosis. Herein, 3 experiments were conducted using a semi-automated in vitro gas production technique. In the experiment (Exp.) 1, the efficacy of 9 plant extracts (1.5 mg/ml), compared to monensin (MON; 12 μg/ml), to counteract ruminal acidosis stimulated by adding glucose (0.1 g/ml) as a fermentable carbohydrate without buffer was assessed for 6 h. In Exp. 2, cinnamon extract (CIN) and MON were evaluated to combat glucose-induced acidosis with buffer use for 24 h. In Exp. 3, the effect of CIN and MON on preventing acidosis when corn or barley grains were used as substrate was examined.

Results

In Exp. 1, cinnamon, grape seeds, orange, pomegranate peels, propolis, and guava extracts significantly increased (P < 0.05) pH compared to control (CON). Both CIN and MON significantly increased the pH (P < 0.001) but reduced cumulated gas production (P < 0.01) compared to the other treatments. In Exp. 2, the addition of CIN extract increased (P < 0.01) pH value compared to CON at the first 6 h of incubation. However, no significant differences in pH values between CIN and CON at 24 h of incubation were observed. The addition of CIN extract and MON decreased (P < 0.001) lactic acid concentration and TVFA compared to CON at 24 h. The CIN significantly (P < 0.01) increased acetate: propionate ratio while MON reduced it. In Exp. 3, both CIN and MON significantly increased (P < 0.05) ruminal pH at 6 and 24 h and reduced lactic acid concentration at 24 h compared to CON with corn as substrate. However, CIN had no effect on pH with barley substrate at all incubation times.

Conclusions

It can be concluded that CIN can be used effectively as an alternative antibiotic to MON to control ruminal acidosis when corn is used as a basal diet.

A Background Search on the Potential Role of Scutellaria and Its Essential Oils

Scutellaria (Lamiaceae), which contains over 350 species, usually known as skullcaps, is found throughout Europe, the United States, and East Asia. In traditional Chinese medicine, several species are used to wipe out heat-evil and remove surface ills (TCM). The current study examines the ethnopharmacology, biological activity, and chemical substances associated with Scutellaria species. More than 295 chemicals, including flavonoids and diterpenes, have been identified. Scutellaria and its active principles have been shown in studies to have a wide range of pharmacological activities, including antioxidant, antimicrobial, antifeedant, phytotoxic, acaricidal toxicity, antibacterial, anti-inflammatory, and antianalgesic activities. Currently, effective monomeric compounds or active components from Scutellaria have been evaluated for pharmacological action in vivo and in vitro. More data facilitates applications and exploitation of novel medication development.

Proximate composition and spatio-temporal heterogeneity of phytochemicals in Agave sisalana Perrine (sisal) adapted in different agro-ecological zones of Punjab, Pakistan

Exploring extractable phytochemicals from locally adapted sisal plant vegetation vary seasonally at different locations. This study elaborated proximate composition and phytochemical heterogeneity in sisal due to varying environmental conditions analyzed from five districts, i.e., Chakwal, Khushab, Rawalpindi, Faisalabad, and Layyah in Punjab, Pakistan. Extensive surveying and plant sampling across 2 years 2017-2018 and 2018-2019, during mid-spring, summer, autumn, and winter seasons were carried out for understanding the seasonal impact on sisal. The present study was designed in a randomized complete block design (RCBD) and analyzed considering seasonal, yearly, and locational impact. The spatial differences in phytochemicals concentration were strongly associated with environmental conditions prevailing in different seasons. Autumn season reflected saponins, tannins, and flavonoids in higher concentrations during 2018-2019 while steroids and terpenoids were higher during spring 2018-2019. Spatio-temporal variations in the proximate analysis were more apparent in different samples collected from different districts. Data recorded for the Khushab district and autumn season reflected the higher composition of a proximate analysis and phytochemical contents as compared to other seasons. Overall, the spatial differences in phytochemicals concentration were strongly associated with soils and environmental conditions prevailing in different seasons in selected districts.

Antagonistic activity and mechanism of Lactobacillus rhamnosus SQ511 against Salmonella enteritidis

Salmonella enteritidis is an important food-borne pathogen. The use of antibiotics is a serious threat to animal and human health, owing to the existence of resistant strains and drug residues. Lactic acid bacteria, as a new alternative to antibiotics, has attracted much attention. In this study, we investigated the antibacterial potential and underlying mechanism of Lactobacillus rhamnosus SQ511 against S. enteritidis ATCC13076. The results revealed that L. rhamnosus SQ511 significantly inhibited S. enteritidis ATCC13076 growth or even caused death. Laser confocal microscopic imaging revealed that the cell-free supernatant (CFS) of L. rhamnosus SQ511 elevated the reactive oxygen species level and bacterial membrane depolarization in S. enteritidis ATCC13076, leading to cell death. Furthermore, L. rhamnosus SQ511 CFS had severely deleterious effects on S. enteritidis ATCC13076, causing membrane destruction and the release of cellular materials. In addition, L. rhamnosus SQ511 CFS significantly reduced the expression of virulence, motility, adhesion, and invasion genes in S. enteritidis ATCC13076 (P < 0.05), and considerably inhibited motility and biofilm formation capacity (P < 0.05). Thus, antimicrobial compounds produced by L. rhamnosus SQ511 strongly inhibited S. enteritidis growth, mobility, biofilm formation, membrane disruption, and reactive oxygen species generation, and regulated virulence-related gene expressions, presenting promising applications as a probiotic agent.

Screening of Candidate Bioactive Secondary Plant Metabolite Ion-Features from Moringa oleifera Accessions Associated with High and Low Enteric Methane Inhibition from Ruminants

This study evaluated the relationship of secondary bioactive plant metabolite ion-features (MIFs) of Moringa oleifera accessions with antimethanogenesis to identify potential MIFs that were responsible for high and low methane inhibition from ruminants. Plant extracts from 12 Moringa accessions were evaluated at a 50 mg/kg DM feed for gas production and methane inhibition. Subsequently, the accessions were classified into low and high enteric methane inhibition groups. Four of twelve accessions (two the lowest and two the highest methane inhibitors), were used to characterize them in terms of MIFs. A total of 24 samples (12 from lower and 12 from higher methane inhibitors) were selected according to their methane inhibition potential, which ranged from 18% to 29%. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and untargeted metabolomics with univariate and multivariate statistical analysis with MetaboAnalyst were used in the study. Although 86 MIFs showed (p < 0.05) variation between higher and lower methane inhibition groups and lay within the detection ranges of the UPLC-MS column, only 14 were significant with the volcano plot. However, Bonferroni correction reduced the candidate MIFs to 10, and their R2-value with methane production ranged from 0.39 to 0.64. Eventually, MIFs 4.44_609.1462 and MIF 4.53_433.1112 were identified as bioactive MIFs associated with higher methane inhibition, whereas MIF 9.06_443.2317 and 15.00_487.2319 were associated with lower methane inhibition with no significant effect on in vitro organic matter digestibility of the feed. These MIFs could be used by plant breeders as potential markers to develop new M. oleifera varieties with high methane inhibition characteristics. However, further investigation on identifying the name, structure, and detailed biological activities of these bioactive metabolites needs to be carried out for future standardization, commercialization, and application as dietary methane mitigation additives.

Influence of microbial probiotics on ruminant health and nutrition: sources, mode of action and implications

Globally, ruminant production contributes immensely to the supply of the highest quality and quantity of proteins for human consumption, sustenance of livelihoods, and attainment of food security. Nevertheless, the phasing out of antibiotics in animal production has posed a myriad of challenges, including poor growth, performance and nutrient utilization, pathogen colonization, dysbiosis, and food safety issues in ruminants. Probiotics (direct-fed microbials), comprising live microbial strains that confer health and nutritional benefits to the host when administered in appropriate quantities, are emerging as a viable, safe, natural and sustainable alternative to antibiotics. Although the mechanisms of action exerted by probiotics on ruminants are not well elucidated, dietary probiotic dosage to ruminants enhances development and maturation, growth and performance, milk production and composition, nutrient digestibility, feed efficiency, pathogen reduction, and mitigation of gastrointestinal diseases. However, the beneficial response to probiotic supplementation in ruminants is not consistent, being dependent on the microbial strain selected, combination of strains, dose, time and frequency of supplementation, diet, animal breed, physiological stage, husbandry practice, and farm management. Nonetheless, several studies have recently reported beneficial effects of probiotics on ruminant performance, health and production. This review conclusively re-iterates the need for probiotics inclusion for the sustainability of ruminant production. Considering the role that ruminants play in food production and employment, global acceptance of sustainable ruminant production through supplementation with probiotics will undoubtedly ensure food security and food safety for the world. © 2021 Society of Chemical Industry.

Progress in Alternative Strategies to Combat Antimicrobial Resistance: Focus on Antibiotics

Antibiotic resistance, and, in a broader perspective, antimicrobial resistance (AMR), continues to evolve and spread beyond all boundaries. As a result, infectious diseases have become more challenging or even impossible to treat, leading to an increase in morbidity and mortality. Despite the failure of conventional, traditional antimicrobial therapy, in the past two decades, no novel class of antibiotics has been introduced. Consequently, several novel alternative strategies to combat these (multi-) drug-resistant infectious microorganisms have been identified. The purpose of this review is to gather and consider the strategies that are being applied or proposed as potential alternatives to traditional antibiotics. These strategies include combination therapy, techniques that target the enzymes or proteins responsible for antimicrobial resistance, resistant bacteria, drug delivery systems, physicochemical methods, and unconventional techniques, including the CRISPR-Cas system. These alternative strategies may have the potential to change the treatment of multi-drug-resistant pathogens in human clinical settings.

Rumen Fermentation of Feed Mixtures Supplemented with Clay Minerals in a Semicontinuous In Vitro System

Interest in using clays in the diets of ruminants to improve health and performance is increasing. The microbial fermentation of 65:35 (HC) or 35:65 (HF) concentrate:forage feeds, alone or with zeolite (Z), bentonite (B), or sepiolite (S), was studied in an in vitro semicontinuous culture system. The medium pH was allowed to drop for the first 6 h and was gradually buffered thereafter. For the HC diet, the medium pH was higher with Z throughout incubation (p < 0.05). Similar results were observed for the HF diet, but with lower differences between the additives. Throughout incubation, the volume of gas produced was higher with HC than HF (p < 0.05). The gas volume with S was the lowest (p < 0.05) for HC, whereas for HF it was lowest with B from 8 h onwards (p < 0.05). No treatment differences (p > 0.05) were observed in dry matter disappearance, microbial mass, or volatile fatty acids. However, the inclusion of B in HC reduced the ammonia concentration at 6 and 12 h with respect to C (p < 0.05). The inclusion of zeolite as an additive in the diets of ruminants stabilizes the rumen environment during the first stages of fermentation in terms of pH and ammonia concentration, especially in high-concentrate diets. The buffering effect of bentonite and sepiolite was lower, and both might reduce ruminal microbial fermentation, depending on the concentrate proportion.

Mangosteen Peel Liquid-Protected Soybean Meal Can Shift Rumen Microbiome and Rumen Fermentation End-Products in Lactating Crossbred Holstein Friesian Cows

Rumen bypass protein can enhance protein availability in the lower gut. This study investigated the use of liquid-containing phytonutrients in dairy cows as a dietary additives to reduce rumen protein degradation. Four crossbred lactating Holstein Friesian cows (75% Holstein Friesian with 25% Thai native breed) with an initial body weight (BW) of 410 ± 20 kg were randomly assigned to a 2 × 2 factorial arrangement [two crude protein (CP) levels with soybean meal (SBM) or mangosteen peel liquid-protected soybean meal (MPLP)-SBM] in a 4 × 4 Latin square design experiment. Dietary treatments were as follows: T1 = SBM in low crude protein concentrate (LPC) (SBM-LPC); T2 = MPLP-SBM in LPC (MPLP-SBM-LPC); T3 = SBM in high crude protein concentrate (HPC) (SBM-HPC); T4 = MPLP-SBM in HPC (MPLP-SBM-HPC). Apparent digestibilities of organic matter (OM) and neutral detergent fiber (aNDF) were increased (p < 0.05) by CP level in the HPC diet (19% CP), with higher OM and aNDF digestibilities. High crude protein concentrate increased (p < 0.05) the propionic acid in the rumen but reduced (p < 0.05) the acetic acid-to-propionic acid ratio and methane (CH4) production. Rumen microbial populations of the total bacteria, Fibrobacter succinogenes and Butyrivibrio fibrisolvens were increased (p < 0.05) by HPC. Real-time PCR revealed a 30.6% reduction of rumen methanogens by the MPLP-SBM in HPC. Furthermore, efficiency of microbial nitrogen synthesis (EMNS) was 15.8% increased (p < 0.05) by the MPLP-SBM in HPC when compared to SBM-LPC. Milk yield and milk composition protein content were enhanced (p < 0.05) by both the CP level in concentrate and by MPLP inclusion. In this experiment, a high level of CP and the MPLP-SBM enhanced the ruminal propionate, shifted rumen microbiome, and enhanced milk yield and compositions.

Meta-analysis of dietary chitosan effects on performance, nutrient utilization, and product characteristics of ruminants

Chitosan (CHI) has been used as a feed additive in ruminant diets, but the effects obtained to date have been varied. This study aimed to evaluate the dietary addition of CHI on performance, nutrient utilization, and product characteristics of ruminants by using a meta-analysis approach. A total of 15 articles that composed of 21 studies and 57 data points were included in the database. Number of articles reported the effects of dietary CHI addition were six on beef cattle, seven on dairy cows, and two papers on sheep. Data analysis was based on the mixed model methodology, in which CHI addition levels were considered as fixed effects whereas different studies were treated as random effects. Results revealed that, across various studies, CHI decreased ruminal acetate proportion (p < 0.05) and increased propionate proportion (p < 0.01). Dry matter and crude protein digestibility were elevated due to CHI addition (p < 0.05). CHI decreased blood cholesterol level (p < 0.05) and increased monounsaturated fatty acid proportion in the milk (p < 0.05). However, CHI addition had no effect on dry matter intake, milk production, and milk efficiency of ruminants. In conclusion, CHI is able to modify rumen fermentation towards a favorable direction, but it limitedly affects performance of ruminants.

Effect of tannins from tropical plants on methane production from ruminants: A systematic review

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A negative relationship was observed between the level of tannin inclusion and CH₄ emission.

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The effect of CH₄ mitigation is increasing as the level of tannin inclusion is higher.

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Sub-group analysis revealed differences of tannins supplementation response according to CH₄ emission measurements techniques.

Methane (CH₄) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH₄ production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH₄ production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH₄ production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The ‘meta’ package in R statistical software was used to conduct the meta-analyses. The covariates defined a priori in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH₄ mitigation . A negative relationship was observed between the level of inclusion and CH₄ emission (−0.09), which means that the effect of CH₄ mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH₄ production will be obtained when supplementing tropical plants in the diet with a high dose of tannins.

Dose-response effects of the Savory (Satureja khuzistanica) essential oil and extract on rumen fermentation characteristics, microbial protein synthesis and methane production in vitro

The objective of the present study was to investigate dose-response effects of the essential oil (EO) and dry extract (EX) of Satureja khuzistanica (SK) on in vitro gas production kinetics, rumen fermentation, ruminal methanogenesis and microbial protein synthesis. So, EO and EX were tested at 0 (as control); 150 (low dose); 300, 450 (intermediate doses) and 600 mg/L (high dose). The gas produced over 24 h of incubation (GP24) decreased linearly with both EO and EX dosages (P<0.01). In vitro methane production was reduced by both EO (14–69%, depending on the included dose) and EX (7–58%). Microbial protein (MP) as well as the efficiency of microbial protein synthesis (EMPS) were improved by EO (18.8–49.8% and 20.4–61.5% for MP and EMPS, respectively) and to a lesser extent by EX (8.3–25.7% and 4.6–24.2% for MP and EMPS, respectively). Ammonia concentration was dropped in linear and quadratic manners with EO (P<0.05), and linearly with EX dosages (P<0.01). EO and EX exhibited depressive effects (in linear and quadratic (P<0.05), and linear manners (P<0.01), respectively) on total protozoa count. A mixed linear and quadratic effect was observed from both EO and EX on total VFA concentration (P<0.01). Total VFA concentration increased at 300 mg/L of EX, but decreased at high dose of both EO and EX. The acetate proportion increased with EO intermediate and high dosages, but it decreased at the expense of propionate at low and intermediate doses of EX. In total, these findings confirmed previous research on the great capacity of plant-based feed additives in positively modulating rumen fermentation that their effects may vary depending on the used doses. Specifically, these results suggest that EO and EX have high potentials to improve rumen functions at intermediate doses, which needs to be confirmed by in vivo experiments.

The Next Step to Further Decrease Veterinary Antibiotic Applications: Phytogenic Alternatives and Effective Monitoring; the Dutch Approach

Antibiotics are used to control infectious diseases in both animals and humans. They can be life-saving compounds but excessive use in animal husbandry leads to the development of antibiotic resistance which can impact the public health. Since similar antibiotics are used in both animal and human healthcare, it is important to reduce the use of antibiotics in production animals. In the Netherlands policies have been developed aiming for a decrease of antibiotic usage in animals, and alternatives to antibiotics are investigated. Currently, a one-on-one relationship between farmer and veterinarian is successfully implemented and (national) registration of antibiotic usage is mandatory. Unfortunately, after a 70% decrease in antibiotic usage since 2009, this decrease is now stagnating in most sectors. Innovative strategies are required to facilitate a further reduction. One promising option is a focus on farm management and natural alternatives to antibiotics. The Dutch government has invested in the spread of knowledge of natural remedies and good animal management to support animal health via so called Barnbooks for farmers and veterinarians. Another option is the analysis of on-farm antibiotic use to prevent unregistered applications. New (bio)analytical strategies to monitor the correct and complete registration of antibiotic usage have been developed and trial-tested in the Netherlands. Such strategies support a risk-based monitoring and allow effective selection of high-risk (high antibiotic use or illegal antibiotic) users. Both effective monitoring and the availability and knowledge of alternatives is a prerequisite to achieve a further significant decrease in antibiotic veterinary usage.

In vitro nutritional quality and antioxidant activity of three weed species as feed additives for sheep in the Central Highlands of Mexico

Sheep production is traditional for rural communities in Mexico, based on natural grasslands and semi-stabled feeding. Quality forages are necessary to improve productivity in these systems. Weeds are an alternative to feed ruminants and to manage crops. Also, many plants have secondary metabolites beneficial for livestock. The objective was to assess the nutritive value in vitro and the antioxidant activity of three weeds (Tithonia tubiformis, Cosmos bipinnatus, and Tagetes lucida) and four treatments (T0 = control diet, T1 = diet + 5% T. tubiformis, T2 = diet + 5% C. bipinnatus, and T3 = diet + 5% T. lucida). Nutritive value was determined from chemical composition by standard methods and mineral contents by inductively coupled plasma analyses. Secondary compounds, total phenols (TP), total tannins (TT), condensed tannins (CT), and phenolic compounds, were determined by high-performance liquid chromatography, and total antioxidant activity was determined by measuring the oxygen radical absorbance capacity. Rumen fermentation kinetics and in vitro digestibility of dry matter (IVDMD), organic matter (IVOMD), and neutral detergent fibre (IVNDFD) were determined per species and treatment by in vitro gas production. T. tubiformis had the highest CP and TP contents (P < 0.05), and C. bipinnatus had the highest fibre and CT contents (P < 0.05). Inclusion of T. lucida in the diet resulted in an 18% increase in TP content and a 30% increase in antioxidant activity in comparison to the control diet. No significant differences (P > 0.05) were found in rumen kinetics parameters, IVDMD, IVOMD, IVNDFD, or metabolizable energy, indicating that the tested weeds can be used as additives to increase antioxidant activity in sheep diets without negative effects.

Selected Alternative Feed Additives Used to Manipulate the Rumen Microbiome

Simple Summary

The continuous intensification of ruminant production drives towards the expansion of feed components and additives that are utilizes for the coverage of animal’s demand for nutrients. Additionally, in recent years, studies are focused on the investigation of how feed additives affect the microbiome of the digestive system in order to obtain improved performance and/or reduce methane emissions by ruminants. The use of additives such as algae, probiotics, fermented feed or essential oils can serve as an alternative to antibiotics or other synthetic compounds that may pose a danger to the environment.

Abstract

In recent years, a boost in the ruminant population has been observed, and consequently, an increase in the animals’ demand for nutrients and methane emissions. Methane emission is generated during the microbial fermentation of feed in the rumen, and a percentage even up to 12% of the energy obtained by this process can be wasted. In addition, the use of antibiotics in animal husbandry is being increasingly restricted. restricted. As a result, there is a continuous search for innovative feed additives that can serve as alternatives to antibiotics, and will also be safe for both people and the environment. In the present review article, additives were selected on basis that, according to studies conducted so far, may positively affect the microbiome of the digestive system by improving indicators and/or reducing methane production. Among them, probiotics, prebiotics or their combination—synbiotics are at the forefront of research. However, additives in the form of algae or plant origin are also gaining ground in popularity, such as essential oils, fermented wheat straw or Gelidium amansii, due to their general recognition as safe (GRAS) for both humans and environment.

The influence of extended supplementation of quebracho extract to beef steers consuming a hay diet on digestion, ruminal, and blood parameters

The addition of natural plant secondary compounds to ruminant feed has been extensively studied because of their ability to modify digestive and metabolic functions, resulting in a potential reduction in greenhouse gas emissions, among other benefits. Condensed tannin (CT) supplementation may alter ruminal fermentation and mitigate methane (CH4) emissions. This study's objective was to determine the effect of quebracho CT extract [QT; Schinopsis quebracho-colorado (Schltdl.) F.A. Barkley & T. Meyer] within a roughage-based diet on ruminal digestibility and kinetic parameters by using the in situ and in vitro gas production techniques, in addition to blood urea nitrogen (BUN) and ruminal (volatile fatty acid [VFA], NH3-N, and protozoa count) parameters. Twenty rumen-cannulated steers were randomly assigned to four dietary treatments: QT at 0%, 1%, 2%, and 3% of dry matter (DM; QT0: 0% CT, QT1: 0.70% CT, QT2: 1.41% CT, and QT3: 2.13% CT). The in situ DM digestibility increased linearly (P = 0.048) as QT inclusion increased, whereas in situ neutral detergent fiber digestibility (NDFD) was not altered among treatments (P = 0.980). Neither total VFA concentration nor acetate-to-propionate ratio differed among dietary treatments (P = 0.470 and P = 0.873, respectively). However, QT3 had lower isovalerate and isobutyrate concentrations compared with QT0 (P ≤ 0.025). Ruminal NH3 and BUN tended to decline (P ≤ 0.075) in a linear fashion as QT inclusion increased, suggesting decreased deamination of feed protein. Ruminal protozoa count was reduced in quadratic fashion (P = 0.005) as QT inclusion increased, where QT1 and QT2 were lower compared with QT0 and QT3. Urinary N excretion tended to reduce in a linear fashion (P = 0.080) as QT increased. There was a treatment (TRT) × Day interaction for in vitro total gas production and fractional rate of gas production (P = 0.013 and P = 0.007, respectively), and in vitro NDFD tended to be greater for QT treatments compared with no QT inclusion (P = 0.077). There was a TRT × Day interaction (P = 0.001) on CH4 production, with QT3 having less CH4 production relative to QT0 on day 0 and QT2 on days 7 and 28. Feeding QT up to 3% of the dietary DM in a roughage-based diet did not sacrifice the overall DM digestibility and ruminal parameters over time. Still, it is unclear why QT2 did not follow the same pattern as in vitro gas parameters. Detailed evaluations of amino acid degradation might be required to fully define CT influences on ruminal fermentation parameters and CH4 production.

Pereira LG, R. Tomich T, A. Carvalho W, S. Silva RO, L. Voorsluys A, V. Jacob D, Magalhães Campos M. Effects of a blend of essential oils in milk replacer on performance, rumen fermentation, blood parameters, and health scores of dairy heifers

The aim of this study was to evaluate how the inclusion of a blend of essential oils in milk replacer (MR) affects different outcomes of dairy heifers. The outcomes evaluated: feed intake, performance, body development, blood cells and metabolites, insulin-like growth factor-1 (IGF-1), rumen fermentation, fecal scores, and respiratory scores. All outcomes were evaluated during pre-weaning (4–60 d of age), and carry-over effects during post-weaning (61–90 d of age) periods. The experimental units utilized were 29 newborn Holstein × Gyr crossbred dairy heifers, with genetic composition of 5/8 or more Holstein and 3/8 or less Gyr and body weight (BW) at birth of 32.2 ± 5.2 kg. Experimental units were assigned to either a control (CON, n = 15) or a blend of essential oil supplementation (BEO, n = 14) treatment, maintaining a balance of genetic composition. The BEO was supplemented in the MR with 1 g/d/calf of a blend of essential oils (Apex Calf, Adisseo, China) composed by plant extracts derived from anise, cinnamon, garlic, rosemary, and thyme. During the pre-weaning phase, all heifers were fed 5 L of MR/d reconstituted to 15% (dry matter basis), divided into two equal meals. Water and starter were provided ad libitum. During the post-weaning, animals received a maximum of 3 kg of starter/d, and ad libitum corn silage, divided into two meals. Feed intake, fecal and respiratory scores were evaluated daily. The BW was measured every three days, while body development was recorded weekly. Blood samples were collected on 0, 30, and 60 d of age for total blood cell count, weekly and on the weaning day to determinate ß-hydroxybutyrate, urea and glucose, and biweekly for IGF-1. Ruminal parameters (pH, volatile fatty acids, ammonia-N, and acetate:propionate proportion—C2:C3) were measured on days 14, 28, 42, 60, 74 and 90. A randomized complete block design with an interaction between treatment and week was the experimental method of choice to test the hypothesis of the BEO’s effect on all outcomes. An ANOVA procedure was used for continuous outcomes, and a non-parametric test was used for the ordered categorical outcomes, both adopting a CI = 95%. Results indicated that there was not enough evidence to accept the alternative hypothesis of the effect of BEO in MR on feed intake, performance, body development, and blood metabolites during both pre-weaning and post-weaning periods. However, results indicated that the inclusion of BEO in MR significantly affects the proportion of C2:C3 during pre- and post-weaning (P = 0.05). Similarly, the effect was significant for basophil (P ≤ 0.001), and platelet (P = 0.04) counts pre-weaning. The interaction between week and treatment was also significant for lymphocytes (P ≤ 0.001), revealing a cumulative effect. Lastly, fecal scores were also significant (P = 0.04) during pre-weaning, with lower values for BEO. The BEO contributed to ruminal manipulation in pre-weaning and carry-over effects in post-weaning, immunity improvement, and decreased morbidity of neonatal diarrhea in the pre-weaning phase.

Evaluation of dietary addition of 2 essential oils from Achillea moschata, or their components (bornyl acetate, camphor, and eucalyptol) on in vitro ruminal fermentation and microbial community composition

This study investigated the effects of 2 Achillea moschata essential oils extracted from plants collected in 2 different valleys of the Italian Alps and 3 pure compounds of oils - bornyl acetate (BOR), camphor (CAM), and eucalyptol (EUCA) - on in vitro ruminal fermentation and microbiota. An in vitro batch fermentation experiment (Exp. 1) tested the addition of all of the substances (2 essential oils and 3 compounds) in fermentation bottles (120 mL) at 48 h of incubation, whereas a subsequent in vitro continuous culture experiment (Exp. 2) evaluated the pure compounds added to the fermenters (2 L) for a longer incubation period (9 d). In both experiments, total mixed rations were incubated with the additives, and samples without additives were included as the control (CTR). Each treatment was tested in duplicate and was repeated in 3 and 2 fermentation runs in Exp. 1 and 2, respectively. Gas production (GP) in Exp. 1 was similar for all of the treatments, and short chain volatile fatty acid (SCFA) production was similar in both experiments except for a decrease of SCFA produced (P = 0.029) due to EUCA addition in Exp. 2. Compared to CTR, BOR and CAM reduced the valerate proportion (P = 0.04) in Exp. 1, and increased (P < 0.01) the acetate proportion in Exp. 2. All treatments increased (P < 0.01) total protozoa counts (+36.7% and +48.4% compared to CTR on average for Exp. 1 and 2, respectively). In Exp. 1, all of the treatments lowered the Bacteroidetes and Firmicutes and increased the Proteobacteria relative abundances (P < 0.05), whereas in Exp. 2, the EUCA addition increased (P = 0.012) the Ruminococcus. In Exp. 1, methane (CH4) as a proportion of the GP was lowered (P = 0.004) by the addition of CAM and EUCA compared to CTR, whereas in Exp. 2, EUCA reduced the amount of stoichiometrically calculated CH4 compared to CTR. Overall, essential oils extracted from A. moschata and the pure compounds did not depress in vitro rumen fermentation, except for EUCA in Exp. 2. In both experiments, an increase of the protozoal population occurred for all the additives.

Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

Influence of a Polyherbal Mixture in Dairy Calves: Growth Performance and Gene Expression

A polyherbal feed mixture containing (Achyrantes aspera, Trachyspermum ammi, Citrullus colocynthis, Andrographis paniculata, and Azadirachta indica) was evaluated in growing calves through blood chemistry, blood biometry, and gene expression during the pre-ruminant to weaning period. Forty Holstein calves (initial BW 45.6 ± 3.2 kg; 22.8 ± 0.9 days post birth) from a dairy farm were randomly assigned to the following treatments: 0, 3, 4, and 5 g/d of a polyherbal mixture, dosed in colloid gels with gelatin. Calves were housed in individual outdoor boxes with ad libitum access to a 21.5% CP calf starter and water and fed individually with a mixture of milk and a non-medicated milk replacer (22% CP). Blood samples were collected on day 59 for blood chemistry, blood biometry, and gene expression analysis in leukocyte through microarray assays. Immunoglobulins were quantified by enzyme-linked immunosorbent assay. The animals treated with the polyherbal mixture showed a quadratic effect on final body weight, daily weight gain, final hip height, and final thoracic girth. The best performance results were obtained with a treatment dose of 4 g/d. The serum IgG increased linearly with the treatment doses. Gene set enrichment analysis of upregulated genes revealed that the three biological processes with higher fold change were tight junction, mucin type O-Glycan biosynthesis, and intestinal immune network for IgA production. Also, these upregulated genes influenced arachidonic acid metabolism, and pantothenate and CoA biosynthesis. Gene ontology enrichment analysis indicated that the pathways enriched were PELP1 estrogen receptor interacting protein pathways, nuclear receptors in lipid metabolism and toxicity, tight junction, ECM-receptor interaction, thyroid hormone signaling pathways, vascular smooth muscle contraction, ribosome function, glutamatergic synapse pathway, focal adhesion, Hippo, calcium, and MAPK signaling pathways.

Phytogenic Additives Can Modulate Rumen Microbiome to Mediate Fermentation Kinetics and Methanogenesis Through Exploiting Diet-Microbe Interaction

Ruminants inhabit the consortia of gut microbes that play a critical functional role in their maintenance and nourishment by enabling them to use cellulosic and non-cellulosic feed material. These gut microbes perform major physiological activities, including digestion and metabolism of dietary components, to derive energy to meet major protein (65-85%) and energy (ca 80%) requirements of the host. Owing to their contribution to digestive physiology, rumen microbes are considered one of the crucial factors affecting feed conversion efficiency in ruminants. Any change in the rumen microbiome has an imperative effect on animal physiology. Ruminal microbes are fundamentally anaerobic and produce various compounds during rumen fermentation, which are directly used by the host or other microbes. Methane (CH4) is produced by methanogens through utilizing metabolic hydrogen during rumen fermentation. Maximizing the flow of metabolic hydrogen in the rumen away from CH4 and toward volatile fatty acids (VFA) would increase the efficiency of ruminant production and decrease its environmental impact. Understanding of microbial diversity and rumen dynamics is not only crucial for the optimization of host efficiency but also required to mediate emission of greenhouse gases (GHGs) from ruminants. There are various strategies to modulate the rumen microbiome, mainly including dietary interventions and the use of different feed additives. Phytogenic feed additives, mainly plant secondary compounds, have been shown to modulate rumen microflora and change rumen fermentation dynamics leading to enhanced animal performance. Many in vitro and in vivo studies aimed to evaluate the use of plant secondary metabolites in ruminants have been conducted using different plants or their extract or essential oils. This review specifically aims to provide insights into dietary interactions of rumen microbes and their subsequent consequences on rumen fermentation. Moreover, a comprehensive overview of the modulation of rumen microbiome by using phytogenic compounds (essential oils, saponins, and tannins) for manipulating rumen dynamics to mediate CH4 emanation from livestock is presented. We have also discussed the pros and cons of each strategy along with future prospective of dietary modulation of rumen microbiome to improve the performance of ruminants while decreasing GHG emissions.

Inhibition of enteric methanogenesis in dairy cows induces changes in plasma metabolome highlighting metabolic shifts and potential markers of emission

There is scarce information on whether inhibition of rumen methanogenesis induces metabolic changes on the host ruminant. Understanding these possible changes is important for the acceptance of methane-reducing practices by producers. In this study we explored the changes in plasma profiles associated with the reduction of methane emissions. Plasma samples were collected from lactating primiparous Holstein cows fed the same diet with (Treated, n = 12) or without (Control, n = 13) an anti-methanogenic feed additive for six weeks. Daily methane emissions (CH₄, g/d) were reduced by 23% in the Treated group with no changes in milk production, feed intake, body weight, and biochemical indicators of health status. Plasma metabolome analyses were performed using untargeted [nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC–MS)] and targeted (LC–MS/MS) approaches. We identified 48 discriminant metabolites. Some metabolites mainly of microbial origin such as dimethylsulfone, formic acid and metabolites containing methylated groups like stachydrine, can be related to rumen methanogenesis and can potentially be used as markers. The other discriminant metabolites are produced by the host or have a mixed microbial-host origin. These metabolites, which increased in treated cows, belong to general pathways of amino acids and energy metabolism suggesting a systemic non-negative effect on the animal.