Plant bioactives for ruminant health and productivity

Potential use of seaweed as a dietary supplement to mitigate enteric methane emission in ruminants

Seaweeds or marine algae exhibit diverse morphologies, sizes, colors, and chemical compositions, encompassing various species, including red, green, and brown seaweeds. Several seaweeds have received increased research attention and application in animal feeding investigations, particularly in ruminant livestock, due to their higher yield and convenient harvestability at present. Recent endeavors encompassing both in vitro and in vivo experiments have indicated that many seaweeds, particularly red seaweed (Asparagopsis taxiformis and Asparagopsis armata), contain plant secondary compounds, such as halogenated compounds and phlorotannins, with the potential to reduce enteric ruminal methane (CH4) emissions by up to 99 % when integrated into ruminant diets. This review provides an encompassing exploration of the existing body of knowledge concerning seaweeds and their impact on rumen fermentation, the toxicity of ruminal microbes, the health of animals, animal performance, and enteric ruminal CH4 emissions in both in vitro and in vivo settings among ruminants. By attaining a deeper comprehension of the implications of seaweed supplementation on rumen fermentation, animal productivity, and ruminal CH4 emissions, we could lay the groundwork for devising innovative strategies. These strategies aim to simultaneously achieve environmental benefits, reduce greenhouse gas emissions, enhance animal efficiency, and develop aquaculture and seaweed production systems, ensuring a high-quality and consistent supply chain. Nevertheless, future research is essential to elucidate the extent of the effect and gain insight into the mode of action.

Phytochemical Study of the Anthelminthic Potential of Guadeloupean Plant Biodiversity

Gastrointestinal parasitism is a major health and welfare problem in ruminants. Synthetic chemical anthelmintic drugs have led to the emergence of resistance in gastrointestinal strongyles, inducing the search for alternatives to control the infections that affect ruminants. The objective of this work was to evaluate the anthelmintic potential of plant extracts against Haemonchus contortus Rudolphi. Three plants of the Guadeloupean biodiversity, Momordica charantia L., Carica papaya L. and Sargassum spp., were selected based on their high polyphenolic content and natural abundance. The phytochemistry of plants was explored, a biological assay against the parasite H. contortus was carried out, and several hypotheses about the way of action were proposed by an innovative electrochemical screening method.

Ruminal modulator additive effect of Stryphnodendron rotundifolium bark in feedlot lambs

The study aimed to evaluate the inclusion effects of Stryphnodendron rotundifolium (barbatimão) extracts in substitution of the lasalocid sodium on the ingestive behaviour, intake, ruminal parameters, and digestibility of feedlot lambs. Twenty-four pantaneiro lambs were used, with an average age of 150 ± 4.59 days and an initial body weight of 21.2 ± 3.63 kg. The lambs were distributed in three treatments in an experimental design with randomized blocks. The treatments correspond to the additive supplements: LAS (0.019 g of lasalocid sodium/lamb/d); DGB (1.50 g of barbatimão dried ground bark/lamb/d); DHE (0.30 g of barbatimão dry hydroalcoholic extract/lamb/d). The DHE increased 59.74 min in the time spent for ingestion per day, resulting in an efficiency reduction of dry matter (DM) ingestion (127 g of DM/h of feed). There was a reduction of 1.8 mg/dL in the ammoniacal nitrogen concentration with extract supplementation compared to LAS. The DGB reduced total volatile fatty acids by 48.9% compared to the control treatment. The inclusion of barbatimão extracts (DGB and DHE) reduced 12.05% of ruminal butyrate content. The supplementation of barbatimão extracts replacing lasalocid sodium in the diet of feedlot lambs did not affect intake and caused small changes on ingestive behaviour.

Reduction of methane and nitrogen emission and improvement of feed efficiency, rumen fermentation, and milk production through strategic supplementation of eucalyptus (Eucalyptus citriodora) leaf meal in the diet of lactating buffalo (Bubalus bubalis)

Buffalo plays a compelling role in reducing malnutrition and ensuring food to the people of Asian countries by its major contribution to milk and meat pool of the livestock agriculture farming system in the region. As Asia is the home for more than 90% of world buffalo population, they are also one of the largest emitters of greenhouse gasses. Eucalyptus (Eucalyptus sp.) leaves are rich sources of naturally occurring essential oils and phenolic compounds, which could modulate rumen fermentation through mitigation of methanogenesis and nitrogen excretion along with stimulation of immune system and production performances of animals. Therefore, the present study investigated the impact of dietary inclusion of eucalyptus (Eucalyptus citriodora) leaf meal (ELM) on voluntary feed intake, rumen functions, methane emission, nutrient utilization, milk yield and fatty acids profile, and immune response in lactating buffalo (Bubalus bubalis). An in vitro experiment conducted with graded dose (10-40 g/kg) inclusion of ELM into the total mixed ration to select ideal level for feeding to lactating buffaloes, an improvement (P < 0.05) in feed degradability (IVDMD), microbial biomass and ruminal volatile fatty acids concentration with reduced (P < 0.05) methane and ammonia-N production were evidenced when ELM was added at 10-20 g/kg DM, beyond which negative effects on rumen fermentation were pronounced. An in vivo experimentation was conducted with sixteen Murrah (Bubalus bubalis) buffaloes of mean live weight, 544.23 ± 10.02 kg; parity, 2-4 at initial stage (~60 days) of lactation with average milk yield of 11.43 ± 1.32 kg and were divided into two groups (CON, ELM) of eight each in a completely randomized design. All the animals were kept individually on wheat straw-based diet with required quantity of concentrate mixture and green fodder. The control group buffaloes were fed a total mixed ration; however, the treatment group (ELM) was supplemented with 10 g/kg DM diet of dry grounded eucalyptus (Eucalyptus citriodora) leaves by mixing with the concentrate mixture. The feeding experiment was conducted for 120 days, including 15 days for adaptation to the experimental diets and 105 days for data recording. The nutrient digestibility (DM, OM, CP, and EE) was improved (P < 0.05) without affecting feed intake (P > 0.05) and fiber digestibility (NDF and ADF) in ELM supplemented buffaloes. Increased (P < 0.05) milk production and rumenic acid concentration (cis 9 trans 11 C18:2 CLA) were demonstrated with comparable (P > 0.05) milk composition and major fatty acids profile of milk in the supplemented buffaloes. Dietary inclusion of ELM reduced (P < 0.05) enteric methane production and fecal excretion of nitrogen. The health status of buffaloes fed ELM improved throughout the experimental period was improved by enhancing cell mediated (P = 0.09) and humoral (P < 0.01) immune responses without affecting (P > 0.05) major blood metabolites. The study described feeding ELM at 10 g/kg diet to lactating Murrah buffaloes as a natural source of phenols and essential oils to increase milk production and CLA content, reduce methane and nitrogen emissions, and improve health status. Thus, feeding of ELM could be beneficial for climate smart buffalo production system for enhancing milk production with lesser impact on environment.

Immunomodulation by cannabidiol in bovine primary ruminal epithelial cells

BACKGROUND

Ruminant livestock experience a number of challenges, including high concentrate diets, weaning and transport, which can increase their risk of disorders such as ruminal acidosis, and the associated inflammation of the ruminal epithelium. Cannabidiol (CBD), a phytochemical from hemp (Cannabis sativa), is a promising target as a therapy for gastrointestinal inflammation, and may be extremely valuable as either a treatment or prophylactic. However, the effects of CBD in the the ruminant gastrointestinal tract have not been explored, in part due to the restrictions on feeding hemp to livestock. Therefore, the objective of this study was to investigate the immunomodulatory properties of CBD using a model of inflammation in primary ruminal epithelial cells (REC). In addition, CBD dose was evaluated for possible cytotoxic effects.

RESULTS

Negative effects on cell viability were not observed when REC were exposed to 10 μM CBD. However, when the dose was increased to 50 μM for 24 h, there was a significant cytotoxic effect. When 10 μM CBD was added to culture media as treatment for inflammation induced with lipopolysaccharide (LPS), expression of genes encoding for pro-inflammatory cytokine IL1B was less compared to LPS exposure alone, and CBD resulted in a down-regulation of IL6. As a pre-treatment, prior to LPS exposure, REC had decreased expression of IL6 and CXCL10 while CBD was present in the media, but not when it was removed prior to addition of LPS.

CONCLUSIONS

Results suggest that CBD may reduce cytokine transcription both during LPS-induced inflammation and when used preventatively, although these effects were dependent on its continued presence in the culture media. Overall, these experiments provide evidence of an immunomodulatory effect by CBD during a pro-inflammatory response in primary REC in culture.

Effect of Dietary Supplementation with a Mixture of Natural Antioxidants on Milk Yield, Composition, Oxidation Stability and Udder Health in Dairy Ewes

Due to the limitations in the use of antibiotic agents, researchers are constantly seeking natural bioactive compounds that could benefit udder health status but also milk quality characteristics in dairy animals. The aim of the current study was therefore to examine the effects of a standardized mixture of plant bioactive components (MPBC) originated from thyme, anise and olive on milk yield, composition, oxidative stability and somatic cell count in dairy ewes. Thirty-six ewes approximately 75 days after parturition were randomly allocated into three experimental treatments, which were provided with three diets: control (C); without the addition of the mixture, B1; supplemented with MPBC at 0.05% and B2; supplemented with rumen protected MPBC at 0.025%. The duration of the experiment was 11 weeks, and milk production was weekly recorded, while individual milk samples for the determination of composition, oxidative stability, somatic cell count (SCC), pH and electric conductivity were collected. Every two weeks, macrophage, lymphocyte, and polymorphonuclear leukocyte counts were also determined in individual milk samples. It was observed that milk yield was the greatest in the B2 group, with significant differences within the seventh and ninth week (p < 0.05), whereas no significant differences were found for milk composition, with the exception of the seventh week, when protein, lactose and non-fat solid levels were lower in MPBC groups (p < 0.05). Oxidative stability was improved in the groups that received the MPBC, with significant differences at the third, seventh, tenth and eleventh week (p < 0.05). SCC was also significantly lower at the second, eighth and ninth week in B2 compared to the other groups (p < 0.05), while no significant effects on the macrophage, lymphocyte, and polymorphonuclear leukocyte counts were observed. In conclusion, the MPBC addition had a positive effect on sheep milk yield, oxidative stability and somatic cell count, without any negative effect on its composition.

Effects of Supplementation with an Herbal Mixture on the Antioxidant Capacity of Milk

The aim of this study was to assess the effect of the addition of a standardized herbal mixture to the feed ration for Holstein-Friesian cows on the antioxidant capacity of milk. The study was carried out on a farm specialized in breeding dairy cattle. The exact study involved 30 cows in lactation III, which were in the first phase of lactation at the beginning of the experiment (15 cows-control group; 15 cows-experimental group). The nutrition supplied to the cows was based on the TMR (total mixed ration) system, with roughage and concentrate fodder used as the basis of the feed ration. The addition of a standardized blend of dried herbs, i.e., oregano (Origanum vulgare), thyme (Thymus vulgaris), purple coneflower (Echinacea purpurea), and cinnamon bark (Cinnamomum zeylanicum), was the experimental factor. Powdered herbs were administered as a component of the concentrate fodder at the dose of 3% DM ration/day/head. Milk samples were collected four times during the experiment (term 0 after the colostrum period and then after lactation weeks 2, 4, and 6). The following parameters were determined in the milk: the basic chemical composition, i.e., the content of total protein, fat, lactose, and casein; somatic cell count; content of selected whey proteins (α-lactalbumin, β-lactoglobulin, lactoferrin, BSA); and fat-soluble vitamins (A, D₃, E). Additionally, the milk antioxidant capacity (ABTS, FRAP, DPPH) was determined and the degree of antioxidant protection (DAP) was calculated. It was shown that the milk from cows receiving the herbal blend-supplemented fodder had a higher content of casein, compared to the control group. The herbal supplementation contributed to a significant increase in the content of bioactive compounds, i.e., selected whey proteins (β-lactoglobulin, lactoferrin) and lipophilic vitamins (A, E). The milk was also characterized by significantly higher antioxidant potential (regardless of the measurement method) and a higher degree of antioxidant protection (DAP).

Roles of Essential Oils, Polyphenols, and Saponins of Medicinal Plants as Natural Additives and Anthelmintics in Ruminant Diets: A Systematic Review

Public awareness on health and safety issues in using antibiotics for livestock production has led many countries to ban the use of all growth-promoting antibiotics (GPA) for livestock feeding. The ban on the utilization of antibiotics in livestock, on the other hand, is an opportunity for researchers and livestock practitioners to develop alternative feed additives that are safe for both livestock and the consumers of animal derived foods. Many feed additives were developed from a number of plants that contain secondary metabolites, such as essential oils, polyphenols, and saponins. These secondary metabolites are extracted from various parts of many types of plants for their uses as feed additives and anthelmintics. Recent investigations on using essential oils, polyphenols, and saponins as dietary additives and anthelmintics demonstrate that they can increase not only the production and health of ruminants but also ensure the safety of the resulting foods. There are many publications on the advantageous impacts of dietary plant bioactive components on ruminants; however, a comprehensive review on individual bioactive constituents of each plant secondary metabolites along with their beneficial effects as feed additives and anthelmintics on ruminants is highly required. This current study reviewed the individual bioactive components of different plant secondary metabolites and their functions as additives and anthelmintics to improve ruminant production and health, with respect to safety, affordability and efficiency, using a systematic review procedure.

Effects of fennel (Foeniculum vulgare) seed powder addition during early lactation on performance, milk fatty acid profile, and rumen fermentation parameters of Holstein cows

Introduction

Aromatic and herbal plants usage as feed additives have become a new tendency in dairy cows’ nutrition to enhance animal performance. This experiment was performed to study the effects of supplementing fennel seed powder (FSP) to diets during early lactation on performance, milk fatty acid (FA) profile, and rumen fermentation of Holstein dairy cows.

Methods

Twenty-four primiparous Holstein dairy cows (10 ± 3 d in milk, 30 ± 2.1 Kg of milk/d, 610 ± 31 Kg body weight; mean ± SE) were balanced for actual milk yield and calving date (n = 8 per treatment) in a complete randomized design. Animals were allocated randomly to diets containing 0 g/d (0FSP), 25 g/d (25FSP), or 50 g/d (50FSP) FSP, individually top-dressed over the total mixed ration. The experimental period was 45 d consisting of the first 15 d for adaptation and the final 30 d for data collection and sampling.

Results and discussion

Dry matter intake responded quadratically to FSP feeding, and cows fed 25FP treatment had greater DMI than 0FSP treatment. The average ruminal pH value decreased linearly as FSP increased in diets. Ruminal valerate and isovalerate proportion increased linearly as FSP inclusion in diets increased, while acetate proportion decreased and acetate:propionate ratio tended to decrease linearly. Increasing FSP in diets linearly increased serum glucose, globulin, and total protein concentrations. Milk yield increased linearly as FSP inclusion in diets increased, whereas milk composition was unaffected. Increasing FSP in diets linearly increased de novo and mixed FA and decreased preformed FA in milk. Dietary treatments did not affect saturated FA, whereas unsaturated FA, mono and poly unsaturated FA linearly decreased with increasing FSP inclusion in diets. Moreover, the content of C18:0 tended to decrease, and C18:1 cis-9 decreased linearly as FSP inclusion increased. Also, increasing the FSP level in diets decreased linearly non-esterified fatty acids and acetone concentrations in the milk. It could be concluded that FSP addition at 50 g/d could enhance performance of early lactating cows.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

Effect of sainfoin (Onobrychis viciifolia) on cyathostomin eggs excretion, larval development, larval community structure, and efficacy of ivermectin treatment in horses

Alternative strategies to chemical anthelmintics are needed for the sustainable control of equine strongylids. Bioactive forages like sainfoin (Onobrychis viciifolia) could contribute to reducing drug use, with the first hints of in vitro activity against cyathostomin free-living stages observed in the past. We analysed the effect of a sainfoin-rich diet on cyathostomin population and the efficacy of oral ivermectin treatment. Two groups of 10 naturally infected horses were enrolled in a 78-day experimental trial. Following a 1-week adaptation period, they were either fed with dehydrated sainfoin pellets (70% of their diet dry matter) or with alfalfa pellets (control group) for 21-days. No difference was found between the average fecal egg counts (FECs) of the two groups, but a significantly lower increase in larval development rate was observed for the sainfoin group, at the end of the trial. Quantification of cyathostomin species abundances with an ITS-2-based metabarcoding approach revealed that the sainfoin diet did not affect the nemabiome structure compared to the control diet. Following oral ivermectin treatment of all horses on day 21, the drug concentration was lower in horses fed with sainfoin, and cyathostomin eggs reappeared earlier in that group. Our results demonstrated that short-term consumption of a sainfoin-rich diet does not decrease cyathostomin FEC but seems to slightly reduce larval development. Consumption of dehydrated sainfoin pellets also negatively affected ivermectin pharmacokinetics, underscoring the need to monitor horse feeding regimes when assessing ivermectin efficacy in the field.

Supplementation of Oilseeds to an Herbage Diet High in Condensed Tannins Affects Methane Production with Minimal Impact on Ruminal Fermentation in Continuous Culture

Condensed tannins (CT) have been observed to reduce enteric CH4 production when added to ruminant diets. However, high concentrations of CT in forages such as sericea lespedeza (SL; Lespedeza cuneata (Dum. Cours.) G. Don) may depress nutrient digestibility. Oilseed crops, high in lipid concentration, also reduce enteric CH4 via toxicity to methanogenic bacteria with less depression of nutrient digestibility. However, it is unclear whether combining these two feeds would result in even greater decreases in CH4 without impairing ruminal fermentation. This study used an in vitro continuous culture fermentor system to determine if supplementation of ground oilseeds would further reduce enteric CH4 production while improving nutrient digestibility of high-CT forages. The experimental design was a 4 × 4 Latin square, with four diets containing (dry matter basis) 45% orchardgrass (OCH; Dactylis glomerata L.), 45% sericea lespedeza (SL; Lespedeza cuneata (Dum. Cours.) G. Don), and 10% oilseed supplements, using canola (CAN; Brassica napus L.), soybean (SOY; Glycine max L.), sunflower (SUN; Helianthus annuus L.), or a mix of all three species (MIX; in equal proportions). Fermentors were fed 82 g of dry matter/d in four equal feedings over four 10 d periods. Methane was recorded every 10 min, and effluent samples were analyzed for pH, volatile fatty acids, dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber to determine apparent and true nutrient digestibilities. The CAN, SUN, and MIX diets had greater concentrations of crude fat (7–8 g/kg) than the SOY diet (5.7 g/kg), which contributed to the greater reduction in enteric CH4 production in those diets (13–27 mg/d) compared to the SOY diet (84 mg/d). Apparent and true nutrient digestibilities were not affected by the addition of ground oilseeds. While N intake increased concomitant with crude protein increases in the diets, there were no additional effects on N flows. While supplementing a high-CT diet with any of the three oilseeds (canola, soybean, sunflower, or a mixture of the three oilseeds) reduced total CH4 emission without depressing nutrient digestibility, canola and mixes containing canola were most effective. Further research is needed in vivo to evaluate whether these results translate to greater feed efficiency and animal production.

Fresh Phyllanthus emblica (Amla) Fruit Supplementation Enhances Milk Fatty Acid Profiles and the Antioxidant Capacities of Milk and Blood in Dairy Cows

The objective of this study was to investigate the effect of a diet supplemented with fresh amla fruit as a natural feed additive on blood metabolic parameters, milk antioxidant capacity, and milk fatty acid (FA) proportions in lactating dairy cows. Eight ruminally cannulated mid-lactation dairy cows were used in a repeated crossover design. The first group of four cows received total mixed ration (TMR) feed without fresh amla fruit (control group). The remaining four cows sequentially supplemented fresh amla fruit (FAF) at three levels (200, 400, then 600 g/d) (treatment group) at 14-day intervals. In second period, control and treatment groups were exchanged. The first ten days were adjusted to diet adaptation for each sub-period, and the last four days for sampling milk and blood. A total of 514 metabolites were detected from FAF using UPLC-ESI-MS/MS. The five main metabolites in FAF were phenolic acids (22%), flavonoids (20%), lipids (20%), amino acids and derivatives (9%), and tannins (7%). Amla fruit supplementation reduced total saturated fatty acid and the omega-6/omega-3 ratio at 200 or 400 g/d FAF dose compared to controls. In addition, amla fruit increased unsaturated FA, such as C_20:5 (Eicosapentaenoic acid, EPA) and C_22:6 (docosahexaenoic acid, DHA), and branched-chain FA in a dose-dependent manner at 200 or 400 g/d compared to controls. In addition, amla fruit increased the antioxidant capacity biomarkers in the blood, such as superoxide dismutase (SOD) and albumin; this confirms that amla fruit is an excellent antioxidant, inhibiting reactive oxygen species’ (ROS) metabolism, and can thereby protect cells from oxidative stress. Moreover, the most remarkable improvement of ferric reducing-antioxidant power (FRAP) and total antioxidant capacity (TAC) in milk was recorded at 400 g/d FAF doses compared to controls. Therefore, fresh amla fruit doses for lactating cows at 400 g/d on an as-fed basis can be used as an alternative additive feed in dairy cow diets to improve antioxidant capacity, protein efficiency, butter quality, and to produce more desirable milk fatty acid profiles for human consumption.

The role of seaweed as a potential dietary supplementation for enteric methane mitigation in ruminants: Challenges and opportunities

Seaweeds are macroalgae, which can be of many different morphologies, sizes, colors, and chemical profiles. They include brown, red, and green seaweeds. Brown seaweeds have been more investigated and exploited in comparison to other seaweed types for their use in animal feeding studies due to their large sizes and ease of harvesting. Recent in vitro and in vivo studies suggest that plant secondary compound-containing seaweeds (e.g., halogenated compounds, phlorotannins, etc.) have the potential to mitigate enteric methane (CH4) emissions from ruminants when added to the diets of beef and dairy cattle. Red seaweeds including Asparagopsis spp. are rich in crude protein and halogenated compounds compared to brown and green seaweeds. When halogenated-containing red seaweeds are used as the active ingredient in ruminant diets, bromoform concentration can be used as an indicator of anti-methanogenic properties. Phlorotannin-containing brown seaweed has also the potential to decrease CH4 production. However, numerous studies examined the possible anti-methanogenic effects of marine seaweeds with inconsistent results. This work reviews existing data associated with seaweeds and in vitro and in vivo rumen fermentation, animal performance, and enteric CH4 emissions in ruminants. Increased understanding of the seaweed supplementation related to rumen fermentation and its effect on animal performance and CH4 emissions in ruminants may lead to novel strategies aimed at reducing greenhouse gas emissions while improving animal productivity.

Benefits and Challenges of Jatropha Meal as Novel Biofeed for Animal Production

Jatropha curcas L. has gained importance as a source of seed oil for biodiesel production. The meal contained about 60% protein with a good balance of essential amino acids, containing various bioactive compounds, including saponins, phytic acids, trypsin inhibitors, lectins, phenolics, and flavonoids, which render it as a potential biofeed for animal production. The Jatropha meal demonstrated various biological activities, including antioxidant, antibacterial, and anti-inflammatory effects which enhance its property as a bio-feed. The levels of these bioactive compounds in the seeds are dependent on the genotypes. The J. curcas possessed different varieties which are either toxic or non-toxic according to the presence of phorbol esters. The presence of phorbol esters in the meal confirmed the toxic variety of Jatropha resulting in the limited application of meal as a biofeed. The Jatropha meal devoid of phorbol esters could be applied as a biofeed in the animal production industry, and for the toxic varieties, various techniques such as physicochemical and biological treatments have been introduced to the industry to remove the phorbol esters from Jatropha meal. Several studies employing various cells and animals confirmed the toxicity of the phorbol esters. The molecular mechanism of action of phorbol esters is through up-regulation of PKC-β II gene, overexpression of down-stream proto-oncogenes resulted in inflammation and oxidative stress ending by apoptotic cell death. Despite the presence of valuable bioactive compounds in the Jatropha meal, its nutritional application is not recommended unless the phorbol esters are completely removed.

Influence of dietary phytogenic feed additives on lactation performance, methane emissions and health status of Murrah buffaloes (Bubalus bubalis)

BACKGROUND

Several feed additives have been used in recent past to reduce enteric methane production in ruminants. But most of them also inhibit feed digestibility and rumen fermentation, thereby lowering animal performance. Phytogenic feed additives are gaining importance owing to their safety in regard to human health issues. The present study examined the effect of dietary supplementation of phytogenic feed additive containing a blend of poplar (Populus deltoides) and eucalyptus (Eucalyptus citriodora) leaves on feed utilization, milk production, methane emissions and health status of Murrah buffaloes (Bubalus bubalis).

RESULTS

The daily milk yield, 6% fat corrected milk yield, and fat-protein corrected milk yield were increased (P < 0.05) in phytogenic composite feed additive (PCFA)-supplemented buffaloes. A decrease (37.3%) in methane concentration in exhaled air of supplemented buffaloes was evident. The digestibility coefficient of dry matter, organic matter and neutral detergent fibre was increased (P < 0.05) in PCFA-fed buffaloes without affecting feed intake. Total digestible nutrient content of the ration fed to buffaloes of the PCFA group was significantly (P < 0.05) increased. The buffaloes fed PCFA exhibited an enhanced cell-mediated and humoral immune response.

CONCLUSION

A discernible positive impact was evident on overall performances and health status along with lowered methane production of buffaloes fed (15 g kg^-1 dry matter intake) a blend of phytogenic feed additive composed of leaves of poplar (P. deltoides) and eucalyptus (E. citriodora). © 2021 Society of Chemical Industry.

Response of Growth Performance, Blood Biochemistry Indices, and Rumen Bacterial Diversity in Lambs to Diets Containing Supplemental Probiotics and Chinese Medicine Polysaccharides

This study aims to investigate the effects of probiotics and Chinese medicine polysaccharides (CMPs) on growth performance, blood indices, rumen fermentation, and bacteria composition in lambs. Forty female lambs were randomly divided into four groups as follows: control, probiotics, CMP, and compound (probiotics + CMP) groups. The results showed that probiotics treatment increased the concentrations of blood glucose (GLU) and immunoglobulin G (IgG) and enhanced rumen microbial protein contents but declined the value of pH in rumen fluid compared with the control (P < 0.05). Furthermore, supplementation with CMP enhanced the average daily gain (ADG) and the contents of IgA, IgG, and IgM in the serum but decreased the F:G ratio compared with the control (P < 0.05). Besides, both CMP and compound (probiotics + CMP) treatments decreased the ratio of acetic acid and propionic acid compared with the control (P < 0.05). High-throughput sequencing data showed that at the genus level, the relative abundance of Veillonellaceae_UCG-001 in the probiotics group was increased, the relative abundance of Succiniclasticum and norank_f__Muribaculaceae in the CMP group were enhanced, and the relative abundance of Ruminococcaceae_UCG-002 in the compound group was raised compared with the control (P < 0.05). In summary, supplementation with probiotics can promote rumen protein fermentation but decrease the diversity of bacteria in rumen fluid; however, CMP treatment increased the relative abundance of Fibrobacteria, changed rumen microbial fermentation mode, increased the immune function, and ultimately improved the growth performance.

Plant cell wall chemistry: implications for ruminant utilisation

Ruminants have adapted to cope with bulky, fibrous forage diets by accommodating a large, diverse microbial population in the reticulo-rumen. Ruminants are dependent on forages as their main sources of energy and other nutrients. Forages are comprised of a complex matrix of cellulose, hemicellulose, protein, minerals and phenolic compounds (including lignin and tannins) with various linkages; many of which are poorly defined. The composition and characteristics of polysaccharides vary greatly among forages and plant cell walls. Plant cell walls are linked and packed together in tight configurations to resist degradation, and hence their nutritional value to animals varies considerably, depending on composition, structure and degradability. An understanding of the inter-relationship between the chemical composition and the degradation of plant cell walls by rumen microorganisms is of major economic importance to ruminant production. Increasing the efficiency of fibre degradation in the rumen has been the subject of extensive research for many decades. This review summarises current knowledge of forage chemistry in order to develop strategies to increase efficiency of forage utilisation by ruminants.

Corn-Soybean Intercropping Improved the Nutritional Quality of Forage Cultivated on Podzols in Boreal Climate

Intercropping systems could be a potential source of nutrient-rich forage production in cool climates on podzolic soils common in boreal ecosystems. In this study, we evaluated the effects of corn-soybean intercropping (IC) on the nutritional quality of forage. Two silage corn varieties were cultivated as monocropping (MC) or were intercropped with three forage soybean varieties using a randomized complete block design. IC significantly increased the crude protein (22%) and decreased the acid detergent (14%) and neutral detergent (6%) fibers. Forage net energy, total digestible nutrients, ash, dry matter intake, digestible dry matter and relative feed value were also significantly increased (p ≤ 0.05) in the IC treatments compared to corn MC. The macro and micro nutrients were higher in IC than corn MC. Intercropping increased the omega 3 fatty acid (FA) contents (67%) compared to corn MC. IC also increased the active microbial community in the plant root zone, which may contribute to the improvement in forage nutritional quality because the active soil microbial community composition showed significant correlations with soluble sugars, soluble proteins and potassium contents of the forage. These results demonstrate that corn-soybean IC could be a suitable cropping system to increase the nutritional quality of forage cultivated on podzols in boreal climates. The resultant forage has the potential to be a source of high-value animal feed for livestock production in cool climate regions of the world.

Seasonal Variations of the Nutritive Value and Phytotherapeutic Potential of Cladium mariscus L. (Pohl.) Targeting Ruminant's Production

In our endeavor to identify salt-tolerant plants with potential veterinary uses in ruminants' production strategies, we focused on Cladium mariscus L. Pohl (sawgrass), due to its high total phenolic and tannin content, anti-radical properties, and ethnomedicinal uses. Aerial parts were collected along the year in Southern Portugal and evaluated for the nutritional profile and in vitro organic matter digestibility (IVOMD), aiming for its use as feed. Acetone extracts were appraised for total contents in phenolics (TPC), flavonoids (TFC), and tannins (CTC), as well as the chemical composition by HPLC-DAD and in vitro antioxidant and anti-inflammatory properties, targeting its exploitation as phytotherapeutic products. Sawgrass biomass has a limited nutritive value, due to its high neutral detergent fiber (NDF; 596-690 g kg^-1 dry matter (DM)) and acid detergent fiber (ADF; 330-418 g kg^-1 DM) contents, low crude protein (51.8-87.3 g kg^-1 DM) and IVOMD (172-317 g kg^-1 organic matter (OM)). Despite differences among seasons, the mineral profile was adequate. The extracts were rich in TPC (88-112 mg g^-1), CTC (115-169 mg g^-1), and TFC (18.5-20.2 mg g^-1), and displayed significant antioxidant capacity, particularly in summer and autumn, whilst no seasonal influence was detected for anti-inflammatory properties (30% reduction of nitric oxide production). Eleven phenolics were quantified: chlorogenic, ferulic, and syringic acids were the most abundant, especially in the autumn sample. Overall, despite the low nutritional interest, sawgrass extracts hold the potential as a source of antioxidant and anti-inflammatory phenolic compounds.

A systematic review on the ethnoveterinary uses of mediterranean salt-tolerant plants: Exploring its potential use as fodder, nutraceuticals or phytotherapeutics in ruminant production

ETHNOPHARMACOLOGICAL RELEVANCE

Salt-tolerant plants are well adapted to the harsh conditions of the Mediterranean region, where have been used traditionally as food and medicines for human and animals. In addition, various species are currently recognized as sources of metabolites with pharmacological, cosmetical and nutraceutical interest. Nevertheless, ethnoveterinary data on salt-tolerant plants are dispersed in the literature and there are few discussions on its veterinary potential. Having in mind the rising interest on organic farming, alternatives to chemical substances in livestock production and concern for animal health and welfare practices, these plants may represent an untapped resource for animal management and veterinary purposes. In this sense, the purpose of this work is to summarize the ethnoveterinary knowledge on salt-tolerant plants described in the Mediterranean region, raising awareness to the potential of this group of plants to be used in veterinary science, targeting especially ruminants.

MATERIAL AND METHODS

Literature search (2000-2020) was conducted using Web of Science and Science Direct databases. Ethnoveterinary reports (EVR) concerning salt-tolerant plants were summarized and filtered for ruminants. From the final 29 publications, EVR concerning therapeutic uses were categorized according to its ATCvet code and results analyzed.

RESULTS

A total of 221 EVR were identified from 39 plants, belonging to 21 plant families, targetting ruminants. Ten EVR (4.5%) concerned uses of salt-tolerant species as animal feed, while around 75% of therapeutic uses was represented by three categories: alimentary tract and metabolism (QA; n = 75), dermatologicals (QD; n = 53) and genitourinary system and sex hormones (QG; n = 41). Pistacia lentiscus L., Foeniculum vulgare Mill., Dittrichia viscosa (L.) Greuter, Plantago major L. and Hordeum vulgare L. were the most cited species in the latter categories.

CONCLUSIONS

The ethnoveterinary knowledge on salt-tolerant species hints some plants of veterinary pharmacological potential, but other species deserve further notice. This information should serve as a basis and, coupled with the currently available scientific data on bioactive properties and chemical composition of salt-tolerant species, inspire additional research on the exploitation of this botanical group, as sources of novel products for ruminant nutrition, health and quality of its products.

Seaweed and Seaweed Bioactives for Mitigation of Enteric Methane: Challenges and Opportunities

Seaweeds contain a myriad of nutrients and bioactives including proteins, carbohydrates and to a lesser extent lipids as well as small molecules including peptides, saponins, alkaloids and pigments. The bioactive bromoform found in the red seaweed Asparagopsis taxiformis has been identified as an agent that can reduce enteric CH4 production from livestock significantly. However, sustainable supply of this seaweed is a problem and there are some concerns over its sustainable production and potential negative environmental impacts on the ozone layer and the health impacts of bromoform. This review collates information on seaweeds and seaweed bioactives and the documented impact on CH4 emissions in vitro and in vivo as well as associated environmental, economic and health impacts.

Nematicidal Effect and Histological Modifications Induced by Hydrolysable Tannin Extract on the Third-Stage Infective Larvae of Haemonchus contortus

Haemonchus contortus is the most frequent and most important nematode parasite in the ruminants production of tropical and subtropical regions. There are strains resistant to all families of available anthelmintics. Consequently, the conduction of research to find other resources that allow effective control of this parasitic disease, preferably focusing on green production, is necessary. The aim of this study was to evaluate the effect of hydrolysable tannin extract (HTE) on larvae 3 (L3) of H. contortus in vitro. L3 were exposed to different HTE concentrations and times. In addition, both light and scanning electron microscopy were used to explore physical damage on L3 subjected to HTE activity. After 72 h of incubation, the mean lethal concentration of HTE was 2 mg/mL; this concentration has been previously referred to as safe for consumption in cattle. Scanning electron microscopy revealed H. contortus L3 destruction, damage was evident by separation of the sheath mainly in the cervical and caudal regions of the larva and by rupture of the cuticle with larval evisceration. Our results suggest that hydrolysable tannin extract from chestnut could be considered as a green alternative for parasitic control in ruminants.

Yield, chemical composition, fermentation characteristics, in vitro ruminal variables, and degradability of ensiled amaranth (Amaranthus hypochondriacus) cultivars compared with corn (Zea mays) silage

Silages from four amaranth varieties (A5, A12, A14, and A28) were compared with corn silage (CS) in terms of their yield, chemical composition, phenolic compounds, oxalic acid and nitrate levels, silage fermentation characteristics, in vitro methane production, organic matter disappearance (OMD), microbial crude protein (MCP), ruminal ammonia (NH₃-N), pH, volatile fatty acids, cellulolytic bacteria numbers, protozoa counts, and in situ dry matter (DM) and crude protein (CP) degradability were determined. Forages were harvested 93 d after planting, chopped, and ensiled in plastic buckets for 60 d. The study was based on a randomized complete block design, and data were analyzed using SAS, general linear model (GLM) procedure for normal distribution. Compared with CS, amaranth silages (AMS) had lower ash-free neutral detergent fiber nitrate, OMD (P < 0.001), phosphorus (P = 0.003), and metabolizable energy (ME) (P = 0.043) but higher (P < 0.001) CP, calcium, non-fiber carbohydrates (NFC), acid detergent lignin, ether extract, ash, total phenolics, pH, NH₃-N concentration, MCP, digestible undegradable protein (DUP), and metabolizable protein (MP). Fresh, OM, OMD, ME (P < 0.001), and DM (P = 0.032) yields of AMS from different varieties were higher than CS, with the exception of A5. Overall, amaranth made good quality silage, with some variation, and A28 had the highest yield and nutritional value (CP, NFC, MCP, DUP, and MP). The yield, CP concentration, and nutritional value of A28 silage were higher than CS. Although these in vitro results are promising, they also need to be validated with future in vivo research.

Vernonia anthelmintica (L.) Willd.: An ethnomedicinal, phytochemical, pharmacological and toxicological review

ETHNOPHARMACOLOGICAL RELEVANCE

Vernonia anthelmintica (L.) Willd. (Asteraceae; Purple Fleabane) has a long history of traditional use for the management of several disorders related to skin, central nervous system, kidney, gynecology, gastrointestinal, metabolism, and general health. The review aims to provide updated systematic information on ethnomedicinal uses, phytochemistry, pharmacological uses, toxicity studies, and patented formulations of V. anthelmintica. This review will not only help to identify the research gaps but also provide information to the scientific community for future research requisites.

MATERIAL AND METHODS

Empirical searches were conducted on the medicinal plant via significant search engines like Google Scholar, Scopus-Elsevier, Medline, SciFinder, Web of Science, Directory of Open Access Journal (DOAJ) from inception until June 2018. Besides, references from local literature, books, and non-English journals were also included.

RESULTS

Scientific reports revealed that V. anthelmintica is a popular medicinal plant used in local and traditional medicine to manage various disorders. Phytochemical studies have identified 193 chemical constituents amongst which steroids form the most abundant class, followed by terpenes. Crude extracts and isolated compounds exhibited various pharmacological activities such as anti-vitiligo, anti-diabetic, anti-inflammatory, antipsoriatic, neuroprotective, hepatoprotective, analgesic, antipyretic, antioxidant, antiparasitic, antimicrobial, antiproliferative, immunomodulatory and also helped in managing pulmonary fibrosis and promoting the synthesis of estrogen. Approximately 45 chemical constituents were found to be biologically active. There are only three toxicity reports and 37 patents available on V. anthelmintica.

CONCLUSION

The review suggests that V. anthelmintica act as a promising source for drug development. The potential uses of V. anthelmintica are owing to the presence of phenolic acids, steroids, fatty acids, and terpenes in its composition. However, further studies are needed to explore the exact mechanism of action, pharmacokinetics, chronic toxicological studies, safe dose consumption, and possible interactions with other herbs.

Ruminal fermentation and enteric methane production of legumes containing condensed tannins fed in continuous culture

A continuous-culture fermentor study was conducted to assess nutrient digestibilities, volatile fatty acid (VFA) concentrations, microbial protein synthesis, bacterial nitrogen (N) efficiency, and enteric methane (CH₄) production of four 50:50 grass-legume diets, randomly assigned in a 4 × 4 Latin square design. Four legumes with different concentrations of condensed tannins (CT) were tested: alfalfa [ALF; Medicago sativa L., non-CT legume]; birdsfoot trefoil [BFT; Lotus corniculatus L., low-CT legume]; crown vetch [CV; Securigera varia (L.) Lassen, moderate-CT legume]; and sericea lespedeza [SL; Lespedeza cuneata (Dum. Cours.) G. Don, high-CT legume]. Orchardgrass (Dactylis glomerata L.) was the common forage used in all diets. Four fermentors were evaluated over four 10-d periods by feeding 82 g of dry matter (DM)/d in 4 equal feedings. Methane output was recorded every 10 min. Effluent samples were collected during the last 3 d of the experiment, composited by fermentor and period, and analyzed for pH and VFA, as well as DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber for determination of apparent and true nutrient digestibilities. Microbial protein synthesis and bacterial efficiency were estimated by analysis of N flows and purines. The CT concentrations were 3, 21, 38 and 76 g/kg of DM for ALF, BFT, CV, and SL diets, respectively. The SL diet had decreased fiber digestibilities and total VFA concentrations compared with the other diets. This resulted in the least total CH₄ production in the SL diet. Bacterial N efficiency per kilogram of organic matter truly digested was lower in the SL diet than in the BFT and CV diets. The lowest CH₄ production per unit of digestible nutrients was also found in the SL diet. Further work should be conducted to find optimal diets (by testing other legumes, rations, and sources of CT) for reducing CH₄ emissions without negatively affecting ruminal digestion to maintain or improve productivity.

The Potential Effect of Dietary Tannins on Enteric Methane Emission and Ruminant Production, as an Alternative to Antibiotic Feed Additives – A Review

Antibiotic growth promoters in livestock nutrition cause microbial resistance which produces threats to human health. Therefore, tannins have been considered as natural alternative antibiotic feed additives which possess various biological properties including antimicrobial, anti-inflammatory, antioxidant and immunomodulatory. Additionally, these plants also have antiparasitic and anti-bloat characteristics which contribute to inhibit the enteric methane emission in order to improve nutrient digestibility, milk and meat quality, fatty acids composition and ruminant production. Antibiotic growth promoters have been practiced in animals feeding to increase feed intake, growth rate, weight gain as well as reduce metabolic disorders and energy losses in the rumen. In 2006, the European Union banned the usage of antibiotic growth promoters in the feeding of livestock. This antibiotic resistance issue has increased demand to explore the natural feed additives that might be useful for animal production system. Consequently, natural forages have been categorized as potential feed additives in animal production since it improves nutritive value, protein digestibility, increase amino acid absorption and growth rate. But, some plant materials are usually rich in tannins known as anti-nutritional factors. Therefore, the application of tannin-rich plants in ruminant nutrition needs great precaution due to its possible injurious effects (dose dependent) on animal health such as metabolic disorders. Hence, there is need to give attention to the usage of tannins in ruminant nutrition as an alternative to antibiotics feed additives to investigate its effects on enteric methane emissions and ruminants production. In addition, safety and risk associated with tannins feeding have also been briefly discussed.

Methane production and estimation from livestock husbandry: A mechanistic understanding and emerging mitigation options

Globally, livestock is an important contributor to methane (CH₄) emissions. This paper reviewed the various CH₄ measurement and estimation techniques and mitigation approaches for the livestock sector. Two approaches for enteric livestock CH₄ emission estimation are the top-down and bottom-up. The combination of both could further improve our understanding of enteric CH₄ emission and possible mitigation measures. We discuss three mitigation approaches: reducing emissions, avoiding emissions, and enhancing the removal of emissions from livestock. Dietary management, livestock management, and breeding management are viable reducing emissions pathways. Dietary manipulation is easily applicable and can bring an immediate response. Economic incentive policies can help the livestock farmers to opt for diet, breeding, and livestock management mitigation approaches. Carbon pricing creates a better option to achieve reduction targets in a given period. A combination of carbon pricing, feeding management, breeding management, and livestock management is more feasible and sustainable CH₄ emissions mitigation strategy rather than a single approach.

Nematocidal effect of Piper retrofractum Vahl on morphology and ultrastructure of Strongyloides stercoralis third-stage infective larvae

In a previous research work aimed at discovering natural helminthicides as alternatives to conventional synthetic drugs, Piper retrofractum fruit hexane extract (PHE) has been shown to possess promising nematocidal activity against the third-stage infective larvae of Strongyloides stercoralis. Thus, this study was designed to evaluate the chemical composition and the impact of PHE on symptom and structural alterations of S. stercoralis. Chemical analysis of PHE by gas chromatography-mass spectrometry demonstrated 26 different compounds, constituting 100% of the total composition. The main components were 4-acetylphenyl (4-benzoylphenoxy) acetate (14.86%) and octyl methoxycinnamate (12.72%). Nematocidal bioassays revealed promising potential of PHE against S. stercoralis larvae, with an LC50 value of 0.059 mg/ml, while the reference drug ivermectin exerted higher efficacy, with an LC50 value of 0.020 µg/ml. Behavioural observations under light microscopy revealed that PHE-treated S. stercoralis larvae moved slowly, became paralysed and eventually died during 24 h of incubation. The dead larvae appeared under light microscope as straight worms with unknown vacuoles of different sizes inside their internal bodies. Morphological alterations of the PHE-treated S. stercoralis larvae, such as straight bodies with swollen cuticle, faded transverse annulations and faded longitudinal striations, as well as shallow and smooth lateral longitudinal grooves, were seen clearly under scanning electron microscopy. Ultrastructural changes in the treated larvae, such as protruded lateral longitudinal grooves, loose muscle with vacuolation, dissociation between the hypodermis and cuticle and marked intracellular disorganization with vacuolation, were detected under transmission electron microscopy. The results of this study provide evidence that PHE is toxic against S. stercoralis and also a potential new alternative for anti-Strongyloides chemotherapy.

A multicomponent herbal feed additive improves somatic cell counts in dairy cows - a two stage, multicentre, placebo-controlled long-term on-farm trial

In contrast to natural and historical diets of wild and domesticated ruminants, the diversity of plant species is limited in diets of modern dairy cows. Are "production diseases" linked to this? We conducted a trial to test the effects of a multicomponent herbal feed additive (HFA) on health, performance and fertility traits. A dose-finding study (DF) with 62 cows on 11 commercial farms compared a low (50 g) and a high (100 g) dose of HFA (HFA-50, HFA-100) with a placebo (PL). In a subsequent field trial (FT) with 280 cows on 30 commercial farms, HFA-100 was compared to PL. Cows were randomly assigned to HFA and PL groups and received HFA or PL individually daily from 14 days pre- to 300 days post-calving. Data were analysed with mixed effects models. No differences between HFA and PL were found regarding performance, body condition score and overall culling rates. A tendency towards lower milk urea for HFA-100 compared to PL (p = .06) was found in DF. HFA significantly reduced elevated milk acetone observations (≥10 mg/L) in the first 10 lactation weeks (HFA-100: 4%; HFA-50: 4%; PL: 12%) in DF. HFA-50 significantly reduced lameness incidence (HFA-100: 11%; HFA-50: 2%; PL: 14%) in DF. Calving intervals were 15 days shorter in HFA compared to PL in both trials, which could be confirmed by tendency (p = .07) in FT. In both trials, the proportion of test days with elevated somatic cell score (≥3.0) was significantly lower in HFA compared to PL (DF: HFA-100: 40%, HFA-50: 45% and PL: 55%; FT: HFA-100: 38% and PL: 55%) which is also reflected by tendency (p = .08) in lower culling rates due to udder diseases in FT. HFA showed no negative impact on any of the measured parameters. The effects of HFA indicate a potential of phytochemically rich and diverse feed additives for dairy cows' nutrition and physiology.

Rumen Fermentation Characteristics in Pre- and Post-Weaning Calves upon Feeding with Mulberry Leaf Flavonoids and Candida tropicalis Individually or in Combination as a Supplement

Although flavonoids or yeast have been used as feed additives to improve the production efficiency and health of adult cattle, little information is available on their effects on rumen fermentation in calves. The objective of this study was to investigate the effects of feed supplementation with mulberry leaf flavonoids and Candida tropicalis on performance, blood parameters, and rumen fermentation characteristics during pre-weaning and post-weaning periods. Forty-eight Holstein calves were used in a four-groups trial and were supplemented with (1) no yeast or flavonoids (CON), (2) active dry yeast (ADY; C. tropicalis, 5.0 × 10⁹ CFU/d), (3) flavonoids (FLA; 3 g/d), or (4) yeast and flavonoids (YF; C. tropicalis, 5.0 × 10⁹ CFU/d; flavonoids, 3 g/d). The feeding strategy was as follows: milk replacer was offered at 12% of body weight in two meals per calf each day at age 21 d, and a gradual weaning process was adopted at age 50 to 56 days. Data of daily feed intake, body weight, and serum and rumen fermentation parameters were obtained at 28, 42, 56, and 80 d ages, respectively. A significant time effect and interaction between treatment and time was found for average daily gain, feed efficiency, total volatile fatty acid concentration, and proportion of propionate in calves (p < 0.05). Average daily gain and feed efficiency increased during post-weaning and overall periods for calves in FLA and YF groups compared with CON and ADY groups (p < 0.05). A reduction of fecal scores with supplementation was found in FLA and YF groups (p < 0.05). Rumen fluid pH and ammonia nitrogen concentration remained constant across the groups, whereas total volatile fatty acid concentration and molar proportion of propionate significantly increased during the pre-weaning and overall periods in FLA and YF groups (p < 0.05). Calves in YF group had the highest serum concentrations of IgG and IgA during the overall period (p < 0.05). Additionally, serum β-hydroxybutyric acid concentration was higher in ADY and FLA groups during the post-weaning period (p < 0.05). Supplementation with C. tropicalis showed little effect on increasing growth performance and health compared with flavonoids alone. Meanwhile, the combination of C. tropicalis and flavonoids was not synergistic with respect to improving health and rumen fermentation compared with use of flavonoids alone in pre- and post-weaning calves (p > 0.05).

Suppression of Melatonin 2-Hydroxylase Increases Melatonin Production Leading to the Enhanced Abiotic Stress Tolerance against Cadmium, Senescence, Salt, and Tunicamycin in Rice Plants

Melatonin 2-hydroxylase (M2H) catalyzes the conversion of melatonin into 2hydroxymelatonin (2OHM), which is present in plants at a higher concentration than melatonin. Although M2H has been cloned, the in vivo function of its product is unknown. Here, we generated stable T₂ homozygous transgenic rice plants in which expression of endogenous M2H was suppressed (RNAi lines). However, we failed to generate M2H overexpression transgenic rice due to failure of somatic embryogenesis. The M2H transcript level showed a diurnal rhythm with a peak at night concomitantly with the peak concentration of 2OHM. RNAi rice showed a reduced M2H mRNA level and 2OHM and melatonin concentrations. The unexpected decrease in the melatonin concentration was caused by redirection of melatonin into cyclic 3hydroxymelatonin via a detour catabolic pathway. Thus, the decrease in the melatonin concentration in M2H RNAi rice led to slowed seedling growth and delayed germination. By contrast, the transient increase in the melatonin concentration was of greater magnitude in the M2H RNAi than the wild-type rice upon cadmium treatment due to possible suppression of melatonin degradation. Due to its higher concentration of melatonin, the M2H RNAi rice displayed tolerance to senescence, salt, and tunicamycin stresses. Therefore, the increase in the melatonin concentration caused by suppression of melatonin degradation or by overexpression of melatonin biosynthetic genes enhances stress tolerance in rice.

LC-ESI-QTOF/MS Characterisation of Phenolic Acids and Flavonoids in Polyphenol-Rich Fruits and Vegetables and Their Potential Antioxidant Activities

Polyphenols are naturally occurring compounds found largely in fruits and vegetables. The antioxidant properties of these polyphenols including total phenolic content (TPC), total flavonoid content (TFC), tannin content, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH), 2,2'-azinobis-(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) scavenging abilities and ferric ion reducing antioxidant power (FRAP) were measured among sixteen (16) plant foods (mango, blueberry, strawberry, black carrot, raspberry, dark grapes, garlic, ginger, onion, cherry, plum, apple, papaya, peach, pear and apricot) by modifying, standardising and translating existing antioxidant methods using a 96-well plate reader. Eighteen targeted phenolic acids and flavonoids were characterised and quantified using high-performance liquid chromatography-photometric diode array (HPLC-PDA) and verified by modifying an existing method of liquid chromatography coupled with electrospray-ionisation triple quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS). While most of these compounds were accurately detected by the HPLC-PDA at a low concentration, a few polyphenols in low concentrations could be only be characterised using the LC-ESI-QTOF/MS method. Our results showed that mango possessed the highest overall antioxidant activity, phenolic acid and flavonoid content among the selected fruits. Factor analysis (FA) and Pearson's correlation tests showed high correlations among ABTS, DPPH, FRAP and phenolic acids, implying the comparable capabilities of scavenging the DPPH/ABTS free radicals and reducing ferric ions from the antioxidant compounds in the samples. Phenolic acids contributed significantly to the antioxidant activities, and flavonoids contributed more to tannin content based on the correlations. Overall, methods modified and standardized in this study can provide better understanding of high throughput technologies and increase the reliability of antioxidant data of different plant foods.

Meat quality, fatty acids, volatile compounds, and antioxidant properties of lambs fed pasture versus mixed diet

The aim of the present work was to investigate the effects of feeding regimens (pasture vs. mixed diet) on meat quality, fatty acids, volatile compounds, and antioxidant properties in lamb meat. In total, 24 lambs were allotted into two feeding regimens at 10.23 kg live weight. Lambs were fed on pasture grass (PG group, n = 12) or mixed diet (M group, n = 12). Longissimus thoracis (LT) muscle samples from the M group had a higher intramuscular fat (IMF) (p < 0.05), pH45minvalue (p < 0.01), and ash (p < 0.05) than the PG group. In contrast, the shear force (p < 0.05), L*(p < 0.05), and b* (p < 0.001) in M group were lower than in PG group. Analyses indicated that PG group contained higher linolenic acid (C18:3n3) and docosatrienoic acid (C22:3n6) (p < 0.05) than the M group. Major volatile compounds in the muscles included hexanal, heptanal, nonanal, octanal, 1-pentanol, 1-hexanol, 1-octen-3-ol, and 2,3-octanedione. The levels of hexanal, nonanal, and 2,3-octanedione were significantly lower in PG lamb muscle (p < 0.01). In contrast, 1-pentanol and 1-hexanol levels were higher in M lamb muscle (p < 0.01). Muscle from PG lamb exhibited higher catalase (CAT) and glutathione peroxidase (GPx) activity (p < 0.05). PG muscle also contained a higher radical-scavenging ability (RSA; p < 0.001) and cupric-reducing antioxidant capacity (CUPRAC; p < 0.05). Overall, the improved antioxidant status in PG muscle inhibited lipid peroxidation (aldehydes and ketones), thereby improving the meat quality.

Transcriptome Analysis of Elm (Ulmus pumila) Fruit to Identify Phytonutrients Associated Genes and Pathways

Plant fruit is an important source of natural active phytonutrients that are profitable for human health. Elm (Ulmus pumila) fruit is considered as natural plant food in China that is rich in nutrients. In the present study, high-throughput RNA sequencing was performed in U. pumila edible fruits and leaves and 11,386 unigenes were filtered as dysregulated genes in fruit samples, including 5231 up- and 6155 downregulated genes. Hundreds of pathways were predicted to participate in seed development and phytonutrient biosynthesis in U. pumila by GO, MapMan, and KEGG enrichment analysis, including “seed maturation”, “glycine, serine, and threonine metabolism” and “phenylpropanoid biosynthesis”. ABA-mediated glucose response-related ethylene-activated signaling pathway (e.g., ABI4) were supposed to associate with elm fruit development; unsaturated fatty acids pathway (e.g., ACX2 and SAD) were predicted to participate in determination of fatty acid composition in elm fruit; flavonoid and coumarins biosynthesis (e.g., CYP98A3 and CCoAOMT1) were demonstrated to correlate with the bioactivity of elm fruits in human cancer and inflammation resistance. To provide more information about fruit developmental status, the qRT-PCR analysis for key genes of “phenylpropanoid biosynthesis” and “alpha-Linolenic acid metabolism” were conducted in samples of young fruits, ripe fruit, old fruit, and leaves. Two biosynthetic pathways for unsaturated fatty acid and Jasmonic acid (JA) were deduced to be involved in fruit development in U. pumila and the phenylpropanoid glycoside, syringin, was speculated to accumulate in the early development stages of elm fruit. Our transcriptome data supports molecular clues for seed development and biologically active substances in elm fruits.

In vitro evaluations of pellets containing Delonix regia seed meal for ruminants

The objective of the present research was to determine the influence of various doses of the pellets containing DR seed meal (PEDEM) on in vitro CH₄ gas production, in vitro digestibility, protozoal count, and ruminal fermentation characteristics. The study was designed as a completely randomized design with eight levels of PEDEM supplementation at 0, 2, 4, 6, 8, 10, 12, and 14 mg DM. Gas production rate constants for the insoluble fraction (c) and cumulative gas production at 96 h were quadratically increased when PEDEM was supplemented (P < 0.05). The concentration of NH₃-N was linearly increased when the PEDEM concentration (P < 0.05) was increased, whereas the population of protozoa was linearly decreased when the level of PEDEM supplementation (P < 0.05) was increased. The supplementation of PEDEM in substrate quadratically affected the mean values of in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), and in vitro NDF digestibility (P < 0.05). TVFA, acetic acid (C2), and butyric acid (C4) were not altered by different doses of PEDEM supplementation (P > 0.05). In contrast, the concentration of propionic acid (C3) was quadratically affected with the supplementation of PEDEM (P = 0.05). The inclusion of PEDEM did not change the CH₄ concentration at 6 h of incubation (P > 0.05), whereas the CH₄ concentration at 24 h of incubation and the mean values were linearly reduced with additional doses of PEDEM (P < 0.05). Compared with the control group, the mean CH₄ concentration was reduced at 51.1% with 12 mg PEDEM, whereas 59.6% was reduced with 14 mg PEDEM supplementations. The supplementation of PEDEM at 12 mg has the potential to manipulate rumen fermentation, to manipulate in vitro digestibility and to reduce protozoa and CH₄ production.

Ruminal methane production: Associated microorganisms and the potential of applying hydrogen-utilizing bacteria for mitigation

Methane emission from ruminants not only causes serious environmental problems, but also represents a significant source of energy loss to animals. The increasing demand for sustainable animal production is driving researchers to explore proper strategies to mitigate ruminal methanogenesis. Since hydrogen is the primary substrate of ruminal methanogenesis, hydrogen metabolism and its associated microbiome in the rumen may closely relate to low- and high-methane phenotypes. Using candidate microbes that can compete with methanogens and redirect hydrogen away from methanogenesis as ruminal methane mitigants are promising avenues for methane mitigation, which can both prevent the adverse effects deriving from chemical additives such as toxicity and resistance, and increase the retention of feed energy. This review describes the ruminal microbial ecosystem and its association with methane production, as well as the effects of interspecies hydrogen transfer on methanogenesis. It provides a scientific perspective on using bacteria that are involved in hydrogen utilization as ruminal modifiers to decrease methanogenesis. This information will be helpful in better understanding the key role of ruminal microbiomes and their relationship with methane production and, therefore, will form the basis of valuable and eco-friendly methane mitigation methods while improving animal productivity.

Climate Change and Goat Production: Enteric Methane Emission and Its Mitigation

Simple Summary

Given that goats are considered more climate resilient than other ruminant species, research efforts are therefore needed to understand goat productivity during exposure to high ambient temperatures. Heat stress can affect the digestion and rumen fermentation pattern of goats, which contributes to the reduction in production performance in goats. Diet composition, breed and environmental stresses are common factors which negatively influence rumen function and enteric methane (CH₄) emission. There are three mechanisms by which enteric CH₄ can be reduced: targeting end product of digestion to propionate, providing alternate hydrogen sink and selectively inactivating rumen methanogens. The various strategies that can be implemented to mitigate enteric CH₄ include nutritional interventions, management strategies and application of advanced biotechnological tools.

Abstract

The ability of an animal to cope and adapt itself to the changing climate virtually depends on the function of rumen and rumen inhabitants such as bacteria, protozoa, fungi, virus and archaea. Elevated ambient temperature during the summer months can have a significant influence on the basic physiology of the rumen, thereby affecting the nutritional status of the animals. Rumen volatile fatty acid (VFA) production decreases under conditions of extreme heat. Growing recent evidence suggests there are genetic variations among breeds of goats in the impact of heat stress on rumen fermentation pattern and VFA production. Most of the effects of heat stress on rumen fermentation and enteric methane (CH₄) emission are attributed to differences in the rumen microbial population. Heat stress-induced rumen function impairment is mainly associated with an increase in Streptococcus genus bacteria and with a decrease in the bacteria of Fibrobactor genus. Apart from its major role in global warming and greenhouse effect, enteric CH₄ is also considered as a dietary energy loss in goats. These effects warrant mitigating against CH₄ production to ensure optimum economic return from goat farming as well as to reduce the impact on global warming as CH₄ is one of the more potent greenhouse gases (GHG). The various strategies that can be implemented to mitigate enteric CH₄ emission include nutritional interventions, different management strategies and applying advanced biotechnological tools to find solution to reduce CH₄ production. Through these advanced technologies, it is possible to identify genetically superior animals with less CH₄ production per unit feed intake. These efforts can help the farming community to sustain goat production in the changing climate scenario.

Comparison of a grain-based diet supplemented with synthetic vitamin E versus a lucerne (alfalfa) hay-based diet fed to lambs in terms of carcass traits, muscle vitamin E, fatty acid content, lipid oxidation, and retail colour of meat

Dietary supplementation of vitamin E (VitE) in a synthetic or natural form was examined. Forty-eight lambs were assigned (n = 16) to either a grain-based diet at moderate (MOD, 42 mg∙kg^-1 VitE as all-rac α-tocopheryl acetate) or supranutritional (SUP, 285 mg∙kg^-1 of vitE) levels of synthetic VitE or a lucerne hay-based diet (LUC; 37 mg∙kg^-1 VitE) for 8 weeks. Meat from the LUC group had lower muscle n-6 and PUFA levels compared to meat from the MOD and SUP groups. Despite a similar VitE intake, muscle VitE was higher for LUC compared to MOD, while SUP lambs showed the highest VitE. Lipid oxidation did not differ between groups. For fresh meat, redness tended to be higher in LUC fed lambs than the other two groups, but brownness formation was only lower than the SUP group. For aged meat colour stability, redness tended to be higher in lambs fed SUP and LUC, whereas highest browning occurred in the MOD group.

Citrus and Winery Wastes: Promising Dietary Supplements for Sustainable Ruminant Animal Nutrition, Health, Production, and Meat Quality

Citrus and grapes are the most widely grown fruits globally, with one-third of total production used for juice and wine making. The juice and winemaking processes generate large quantities of solid organic wastes including citrus pulp and grape pomace. These fruit wastes pose serious economic, environmental, and social challenges, especially in low-to-middle-income countries due to financial, technological, and infrastructural limitations. They are, however, rich in valuable compounds which can be utilized in the ruminant livestock industry as novel, economical, and natural sources of cellulose, polyunsaturated fatty acids, and phytochemicals, which have nutritional, anthelmintic, antioxidant, and antimicrobial properties. Despite citrus and grape fruit wastes having such potential, they remain underexploited by the livestock industry in low-to-middle-income countries owing to lack of finance, skills, technology, and infrastructure. Inclusion of these fruit wastes in ruminant diets could combine the desirable effects of enhancing animal nutrition, health, welfare, production, and meat quality attributes with the prevention of challenges associated with their disposal into the environment. The current review explores the valorization potential of citrus and winery wastes as dietary supplements to sustainably enhance ruminant animal nutrition, health, welfare, production, and meat quality.