Dietary sources and their effects on animal production and environmental sustainability

The biomolecules of Euglena gracilis: Harnessing biology for natural solutions to future problems

Over the past decade, the autotrophic and heterotrophic protist Euglena gracilis (E. gracilis) has gained popularity across the studies of environmental science, biosynthesis experiments, and nutritional substitutes. The unique physiology and versatile metabolism of E. gracilis have been a recent topic of interest to many researchers who continue to understand the complexity and possibilities of using E. gracilis biomolecule production. In this review, we present a comprehensive representation of recent literature outlining the various uses of biomolecules derived from E. gracilis across the fields of natural product biosynthesis, as a nutritional substitute, and as bioremediation tools. In addition, we highlight effective strategies for altering metabolite production using abiotic stressors and growth conditions. To better understand metabolite biosynthesis and its role in E. gracilis, integrated studies involving genomics, metabolomics, and proteomics should be considered. Together, we show how the ongoing advancements in E. gracilis related research continue to broaden applications in the biosynthetic sector and highlight future works that would strengthen our understanding of overall Euglena metabolism.

Does Replacing Maize with Barley Affect the Animal Performance and Rumen Fermentation, including Methane Production, of Beef Cattle Fed High-Concentrate Diets On-Farm?

Ruminants fed high-concentrate diets produce less enteric methane than those fed high-forage diets, but not all grains are equally effective in reducing methane production. This study aimed to examine, in farm conditions, the effects of a partial substitution of maize with barley on animal performance and rumen fermentation, including methane production, of intensively reared beef calves (ca. 0.9:0.1 concentrate to forage ratio). Ninety-six beef calves were fed a concentrate with 45.5% maize and 15% barley (n = 48; M) or a concentrate with 15.5% maize and 45% barley (n = 48; B). Both the concentrate and barley straw were offered ad libitum. The type of concentrate did not have a significant effect (p > 0.05) on final live weight, average daily gain, carcass dressing percentage or intake of concentrate and straw. Dry matter and organic matter digestibility were higher (p < 0.05) for the M (75.4% and 76.6%) than for the B (71.0% and 73.1%) treatment, but with no effect on digestible organic matter intake. In general, the majority cereal in the concentrate did not affect rumen fermentation, including methane production, or the degradability of dry matter and starch. A partial substitution of maize with barley in the concentrate offered to beef calves does not seem a promising strategy to decrease the emissions of enteric methane on-farm.

The Association between Charolais Cows' Age at First Calving, Parity, Breeding Seasonality, and Calf Growing Performance

The objective of this study was to evaluate the impact of cows' calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p < 0.05). The gender of the calves affected their weight, indicating that newborns bulls were significantly heavier. Calf gender affected calf growing performance. Male calves' weight gain was higher than that of females in the time before weaning (210 days). The highest gain of bulls was observed from 211 days to 365 days after birth. The average daily weight of male calves during this period was 6.16% (p < 0.001) higher compared to the period up to 210 days after birth. Heifers had a higher daily weight in the period up to 210 days after birth, and the daily weight gain was 12.9% (p < 0.001) higher in this period compared to the period from 211 to 365 days after birth. We observed a higher weight gain in calves from mothers with a higher number of calvings. Being born from cows with four or more calvings had a significant effect on the weight gain of calves in the period up to 210 days (p < 0.05). In the period up to 210 days, the weight gain of calves born from cows with two calvings was the lowest and was 9.79% lower compared to calves born from cows with four and more calvings (p < 0.05). The best weights were obtained from calves born in the spring and autumn seasons. Calves born in spring, summer, and autumn differed in weight by 0.37 kg. The calves of cows that were inseminated in the autumn season had the highest gain in the period up to 210 days and also from 210 to 365 days (p < 0.05). In our study, significantly higher average birth weight of calves was detected in autumn compared to summer and winter (p < 0.05). Also, the highest gain was found from 211 to 365 days after birth in the summer season, but the difference was only 1.47% (p < 0.05).

Effects of Urtica urens in the Feed of Broilers on Performances, Digestibility, Carcass Characteristics and Blood Parameters

With the aim of improving animal health and productivity, plants or plant extracts that have antimicrobial, antifungal and antioxidant properties are often used in studies with broilers. The aim of this work was to investigate the effect of Urtica urens in broilers. Ninety male Ross chicks were used, randomly placed in 30 pens (three broilers per pen). The broilers were assigned to three treatment groups: group CT (control) received a basal diet; group UU1 received a basal diet with 1% dried Urtica urens; and group UU2 received a basal diet with 2% dried Urtica urens. Each treatment consisted of two feeds, distributed from day 1 to 15 (starter) and from day 15 to 36 (grower). As a result of this study, broilers in the UU1 treatment group had higher weight on day 15 (p = 0.029) and day 36 (p = 0.014) than those in treatments CT and UU2 and a higher daily weight gain between days 1 and 15 (p = 0.028) and days 1 and 36 (p = 0.014). Broilers in the UU1 and UU2 groups had lower serum HDL cholesterol (88.8 and 88.9 mg/dL, respectively) than the CT (96.1 mg/dL). In conclusion, the use of dried Urtica urens at 1% as an additive in broiler diets may affect growth performance and blood HDL cholesterol.

Dietary supplementation of Allium mongolicum modulates rumen-hindgut microbial community structure in Simmental calves

Compared to traditional herbage, functional native herbage is playing more important role in ruminant agriculture through improving digestion, metabolism and health of livestock; however, their effects on rumen microbial communities and hindgut fermentation are still not well understood. The objective of present study was to evaluate the effects of dietary addition of Allium mongolicum on bacterial communities in rumen and feces of claves. Sixteen 7-month-old male calves were randomly divided into four groups (n = 4). All calves were fed a basal ration containing roughage (alfalfa and oats) and mixed concentrate in a ratio of 60:40 on dry matter basis. In each group, the basal ration was supplemented with Allium mongolicum 0 (SL0), 200 (SL200), 400 (SL400), and 800 (SL800) mg/kg BW. The experiment lasted for 58 days. Rumen fluid and feces in rectum were collected, Rumen fluid and hindgut fecal were collected for analyzing bacterial community. In the rumen, Compared with SL0, there was a greater relative abundance of phylum Proteobacteria (p < 0.05) and genera Rikenellaceae_RC9_gut_group (p < 0.01) in SL800 treatment. In hindgut, compared with SL0, supplementation of A. mongolicum (SL200, SL400, or SL800) decreased in the relative abundances of Ruminococcaceae_UCG-014 (p < 0.01), Ruminiclostridium_5 (p < 0.01), Eubacterium_coprostanoligenes_group (p < 0.05), and Alistipes (p < 0.05) in feces; Whereas, the relative abundances of Christensenellaceae_R-7_group (p < 0.05), and Prevotella_1 (p < 0.01) in SL800 were higher in feces, to maintain hindgut stability. This study provided evidence that A. mongolicum affects the gastrointestinal of calves, by influencing microbiota in their rumen and feces.

Use of tannin extract as a strategy to reduce methane in Nellore and Holstein cattle and its effect on intake, digestibility, microbial efficiency and ruminal fermentation

This study was carried out to evaluate the use of tannin extract from Acacia mearnsii as a strategy to reduce methane (CH₄ ) in two distinct cattle genotypes and its effect on intake, digestibility, microbial efficiency and ruminal fermentation. Four Nellore (Bos indicus) and four Holstein (Bos taurus) dry cows fitted with rumen cannula were assigned to two 4 × 4 Latin square design, in a 2 × 4 factorial arrangement, where each genotype represented a square receiving four tannin levels (commercial extract of A. mearnsii) in the diet (0%, 0.5%, 1.0% and 1.5% of dry matter). Tannin levels used did not cause a reduction in feed intake or rumen passage rate for both genotypes (p > 0.05), although there was a linear reduction in the degradation rate and ruminal disappearance of diet (p < 0.05). The increase in tannin levels reduced the amount of entodiniomorph protozoa in the Nellore cattle (p < 0.05). There was no change in N retention or microbial efficiency (p > 0.05), despite the linear reduction of nutrient digestibility and the synthesis of microbial nitrogen (p < 0.05). The ruminal CH₄ production was reduced (p < 0.05) without reducing the short-chain fatty acid production. The threshold of 0.72% of tannin in the diet was estimated as the starting point for the reduction of ruminal CH₄ production with long-term efficacy. Therefore, the use of low levels of tannin extract from A. mearnsii is a potential option to manipulate rumen fermentation in Nellore and Holstein cattle and needs to be further investigated.

Reproductive behavior of Pantaneiros sheep, Mato Grosso do Sul, Brazil

The objective was to evaluate fertility, cyclicality behavior, and sexual performance of Pantaneiro sheep throughout the year’s photoperiods in Mato Grosso do Sul - Brazil. Two experiments were conducted. In experiment one, the ewes used aged between 2 and 4 years, distributed in three homogeneous groups of 54 animals and subjected to reproductive evaluation in three different predefined luminosity periods, consisting of autumn (11h 45 min.), spring (12h 30 min.), and summer (12h 55 min.). The characteristics studied were body weight (BW), body condition score (BCC), estrus distribution (EST), percentage of pregnant females per cycle (%P), plasma progesterone (PP), and fertility (F) in the three predefined seasons. The mating system used was controlled natural nocturnal and lasted for 45 days. Experiment two, evaluated the ram sexual activity. The males (10) were individually exposed to four ovariectomized ewes. The ewes cycled during evaluated seasons, and the highest fertility was observed in animals with BCC >2.75. The PP concentration differed among periods, and higher conception rates (F) were observed in autumn and spring. The rams (75%) had a medium  of sexual performance when they performed more than two ejaculations in 20 min throughout the seasons. Pantaneiro sheep of both genders had a similar fertility index, with early and constant activity throughout the year, displaying no photoperiodism or seasonality.

The effect of Origanum syriacum L. extract and carvacrol on the in vitro digestion, estimated digestion values, ammonia and organic acid concentrations in the fermentation fluid of lucerne herbage

The effects induced by medicinal aromatic plants in biological systems vary with the type and amount of bioactive substances these plants contain. Whether the purified form of the main chemical components of these plants, such as carvacrol and thymol, or plant volatile oils containing tens of bioactive compounds are more effective remains a question of debate. This study was aimed at providing a comparative assessment of the effects of Origanum syriacum L. (wild mountain thyme) volatile oil (OSVO) and one of its main components, carvacrol (CRV), on the in vitro ruminal degradability of lucerne herbage and methane production during the degradation of lucerne. For this purpose, wild thyme was harvested at the beginning of the flowering period, and the OSVO was extracted from the plant by steam distillation. Gas production assays were performed in five groups of ruminal fluid samples, one of which was maintained for control purposes, and the other four 40/60/80 mg/l of OSVO and 60 mg/l of CRV were added. Compared to the control group, in the samples with the added CRV and OSVO, the amounts of in vitro total gas and methane production were observed to have been affected, but no decrease was detected in the ruminal protozoa counts. The level of ammonia nitrogen was lowest in the groups, in which CRV and 40 mg/l of OSVO (P < 0.01) were added. The ruminal protozoa counts were not affected by the addition of CRV and OSVO. While the total volatile fatty acid (TVFA) and propionic acid (PA) concentrations in the in vitro fermentation fluid of lucerne herbage were low in all the groups, butyric acid was detected at a level of 40 mg/l in the group where CRV was added. The OSVO was ascertained to have induced dose-dependent alterations in the investigated in vitro digestion parameters. In result, CRV (60 mg/l) and OSVO (40 mg/l) were determined to have shown a relatively positive effect on the in vitro ruminal gas production. The anti-methanogenic effect of the plant extracts was due to the decreased digestibility of the lucerne herbage. This can have a positive impact on the environment, but the same cannot be said for the animal nutrient use and animal performance.

Integrated Metabolomics and Transcriptome Revealed the Effect of Fermented Lycium barbarum Residue Promoting Ovis aries Immunity

Lycium barbarum residue contains abundant bioactive nutrients which can be used as feed supplement. The fermentation treatment of plant residue can promote the utilization of nutrients, rumen digestion, and the growth and immunity of animals. Based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) metabolomics and in-depth transcriptome analysis, the study tested the mechanisms of Lycium barbarum residue (RW) and fermented Lycium barbarum residue (RFW) on meat quality and immunity of sheep. Fifty-four Tan sheep were randomly divided into control, RFW or RW treatments. Data showed that RFW and RW increased the carcass weight, fat content, ash content and reduced the cooking loss of lamb. RFW performed more significant effects on activating immune-related genes than those of RW. The expression of chemokines and immune-related pathways, such as signaling pathways of interleukin-17 signaling pathway and NOD-like receptor signaling pathway, were elevated in sheep fed RFW. RW increased the diversity in rumen metabolites, especially compositions of lipids, organic acids and organ heterocyclic compounds. RFW affected numerous compounds which are closely correlated with the activation of immune genes. In conclusion, RFW could represent a valuable strategy to improve growth performance and immunity of sheep.

Role of probiotics in ruminant nutrition as natural modulators of health and productivity of animals in tropical countries: an overview

Given the ever-growing population in the developing countries located in the tropics of Asia, Africa, South America, and the Caribbean, the demand for products of animal origin has increased. Probiotics have proven to be a substantial substitute for antibiotics used in the animal diet and thus gained popularity. Probiotics are live and non-pathogenic microbes commercially utilized as modulators of gut microflora, hence exerting advantageous effects on the health and productivity of animals in tropical countries. Probiotics are mainly derived from a few bacterial (Lactobacillus, Enterococcus, Streptococcus, Propionibacterium, and Prevotella bryantii) and yeast (Saccharomyces and Aspergillus) species. Numerous studies in tropical animals revealed that probiotic supplementation in a ruminant diet improves the growth of beneficial rumen microbes, thus enhancing nutrient intake and digestibility, milk production, and reproductive and feed efficiency, along with immunomodulation. Furthermore, probiotic applications have proven to minimize adverse environmental consequences, including reduced methane emissions from ruminants' anaerobic fermentation of tropical feedstuffs. However, obtained results were inconsistent due to sources of probiotics, probiotic stability during storage and feeding, dose, feeding frequency, and animal factors including age, health, and nutritional status of the host. Furthermore, the mechanism of action of probiotics by which they exhibit beneficial effects is still not clear. Thus, more definitive research is needed to select the most effective strains of probiotics and their cost-benefit analysis. In this review article, we have briefly explained the impact of feeding probiotics on nutrient intake, digestibility, reproduction, growth efficiency, productivity, and health status of tropical ruminant animals.

A systems approach to analyzing food, energy, and water uses of a multifunctional crop: A review

Multifunctional crops can simultaneously contribute to multiple societal objectives. As a result, they represent an attractive means for improving rural livelihoods. Moringa oleifera is an example of a multifunctional crop that produces nutritious leaves with uses as food, fodder, and a biostimulant to enhance crop growth. It yields seeds containing a water purifying coagulant and oil with cosmetic uses and possible biofuel feedstock. Despite Moringa oleifera's (and other multifunctional crops') various Food-Energy-Water uses, optimizing the benefits of its multiple uses and livelihood improvements remains challenging. There is a need for holistic approaches capable of assessing the multifunctionality of agriculture and livelihood impacts. Therefore, this paper critically evaluates Moringa oleifera's Food-Energy-Water-Livelihood nexus applications to gain insight into the tradeoffs and synergies among its various applications using a systems thinking approach. A systems approach is proposed as a holistic thinking framework that can help navigate the complexity of a crop's multifunctionality. The "Success to the Successful" systems archetype was adopted to capture the competition between the need for leaf yields and seed yields. In areas where there is energy and water insecurity, Moringa oleifera seed production is recommended for its potential to coproduce oil, the water purifying coagulant, and a residue that can be applied as a fertilizer. In areas where food insecurity is an issue, focusing on leaf production would be beneficial due to its significance in augmenting food for human consumption, animal feed, and its use as a biostimulant to increase crop yields. A causal loop diagram was found to effectively map the interconnections among the various uses of Moringa oleifera and associated livelihood improvements. This framework provides stakeholders with a conceptual decision-making tool that can help maximize positive livelihood outcomes. This approach can also be applied for improved management of other multifunctional crops.

In Vitro and In Vivo Evaluation of the Effects of a Compound Based on Plants, Yeast and Trace Elements on the Ruminal Function of Dairy Cows

The high production levels reached by the dairy sector need adjustment in nutritional inputs and efficient feed conversion. In this context, we evaluated a compound (QY—Qualix Yellow) combining optimized inputs in trace elements and 20% MIX 3.0. In a first step, the effects of MIX 3.0 on ruminal function were assessed in vitro by incubating ruminal fluid with the mixture at a ratio of 20:1. The results obtained encouraged us to test QY in vivo, on a herd of dairy cows. The herd was divided into one group of 19 dairy cows receiving the compound and a control group of 20 animals conducted in the same conditions, but which did not received the compound; the production performance and feed efficiency of the two groups were compared. In vitro experiments showed improved digestion of acid and neutral detergent fibres by 10%. The propionate production was enhanced by 14.5% after 6 h incubation with MIX 3.0. The plant mixture decreased the production of methane and ammonia by 37% and 52%, respectively, and reduced the number of protozoa by 50%. An increase in milk yield by 2.4 kg/cow/d (p < 0.1), combined with a decrease in concentrate consumption of 0.27 kg DM/cow/d (p < 0.001), was observed in vivo after consumption of the compound. Sixty-six days after the beginning of the trial, methane emissions per kg of milk were significantly lower in the group receiving QY. In conclusion, MIX 3.0 induced change in ruminal function in vitro and, when it entered into the composition of the QY, it appeared to improve feed efficiency and production performance in vivo.

Supplementation of fruit peel pellet containing phytonutrients to manipulate rumen pH, fermentation efficiency, nutrient digestibility and microbial protein synthesis

BACKGROUND

Phytonutrient pellet, a new rumen enhancer, was formulated from various tropical fruit peels containing phytonutrients (condensed tannins and saponins) and named MARABAC. To substantiate the MARABAC supplementation effect, it was supplemented with low and high levels of concentrate supplementation in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement using beef cattle. Based on this investigation, interesting findings were highlighted and are reported herein.

RESULTS

The high level of concentrate supplementation (HCS) reduced rumen pH remarkably, but was buffered and enhanced by MARABAC supplementation. Rumen pH was reduced to 5.74 at 8 h, post feeding upon receiving HCS, and was buffered back to 6.19 with MARABAC supplementation. The supplementation exhibited an additional pronounced (P < 0.01) effect on improving nutrient digestibility and efficiency of microbial nitrogen supply, mitigating rumen methane production and reducing protozoal population. Rumen and fermentation end-products, especially propionate production, were enhanced (P < 0.05), while rumen methane production was subsequently mitigated (P < 0.01).

CONCLUSION

MARABAC is a new promising dietary rumen enhancer for future replacement of chemicals and antibiotics used to enhance the rumen fermentation. Nevertheless, more in vivo feeding trials should be further conducted to elucidate the insight impacts. © 2021 Society of Chemical Industry.

Innovative high digestibility protein feed materials reducing environmental impact through improved nitrogen-use efficiency in sustainable agriculture

Sustainable development in agriculture brings both environmental and economic benefits. Contemporary agriculture is also about increasing nutrient use efficiency, especially nitrogen, as the critical nutrient causing the most significant environmental pressure. This creates the need to produce highly digestible protein feed with high bioavailability, reducing losses of biogenic elements to feces. In this review, the latest trends and the potential for their implementation in sustainable agriculture have been compared, as well as the need to reduce the negative environmental impact of agriculture has been demonstrated. Applying local protein sources to feed animals reduces greenhouse gas emissions associated with transportation. The production of highly digestible fodder leads to a reduction in environmental pollution caused by excessive nitrogen outflows. Another approach indecreasing ammonia emissions from livestock farming is feed protein reduction and amino acid supplementation. All of the aforementioned approaches may result in beneficial long-term changes, contributing to environmental safety, animal welfare and human health.

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.

Decreased Methane Emissions Associated with Methanogenic and Methanotrophic Communities in a Pig Manure Windrow Composting System under Calcium Superphosphate Amendment

With the rapid growth of livestock breeding, manure composting has evolved to be an important source of atmospheric methane (CH4) which accelerates global warming. Calcium superphosphate (CaSSP), as a commonly used fertilizer, was proposed to be effective in reducing CH4 emissions from manure composting, but the intrinsic biological mechanism remains unknown. Methanogens and methanotrophs both play a key role in mediating CH4 fluxes, therefore we hypothesized that the CaSSP-mediated reduction in CH4 emissions was attributed to the shift of methanogens and methanotrophs, which was regulated by physicochemical parameter changes. To test this hypothesis, a 60-day pig manure windrow composting experiment was conducted to investigate the response of CH4 emissions to CaSSP amendment, with a close linkage to methanogenic and methanotrophic communities. Results showed that CaSSP amendment significantly reduced CH4 emissions by 49.5% compared with the control over the whole composting period. The decreased mcrA gene (encodes the α-subunit of methyl-coenzyme M reductase) abundance in response to CaSSP amendment suggested that the CH4 emissions were reduced primarily due to the suppressed microbial CH4 production. Illumina MiSeq sequencing analysis showed that the overall distribution pattern of methanogenic and methanotrophic communities were significantly affected by CaSSP amendment. Particularly, the relative abundance of Methanosarcina that is known to be a dominant group for CH4 production, significantly decreased by up to 25.3% accompanied with CaSSP addition. Only Type I methanotrophs was detected in our study and Methylocaldum was the dominant methanotrophs in this composting system; in detail, CaSSP amendment increased the relative abundance of OTUs belong to Methylocaldum and Methylobacter. Moreover, the increased SO42- concentration and decreased pH acted as two key factors influencing the methanogenic and methanotrophic composition, with the former has a negative effect on methanogenesis growth and can later promote CH4 oxidation at a low level. This study deepens our understanding of the interaction between abiotic factors, function microbiota and greenhouse gas (GHG) emissions, as well as provides implication for practically reducing composting GHG emissions.

Garlic skin induces shifts in the rumen microbiome and metabolome of fattening lambs

Garlic (Allium sativum L.) and its constituents have been shown to modify rumen fermentation and improve growth performance. Garlic skin, a by-product of garlic processing, contains similar bioactive components as garlic bulb. This study aimed to investigate the effects of garlic skin supplementation on growth performance, ruminal microbes, and metabolites in ruminants. Twelve Hu lambs were randomly assigned to receive a basal diet (CON) or a basal diet supplemented with 80 g/kg DM of garlic skin (GAS). The experiment lasted for 10 weeks, with the first 2 weeks serving as the adaptation period. The results revealed that the average daily gain and volatile fatty acid concentration were higher (P < 0.05) in lambs fed GAS than those in the CON group. Garlic skin supplementation did not significantly (P > 0.10) affect the α-diversity indices, including the Chao1 index, the abundance-based coverage estimator value, and the Shannon and Simpson indices. At the genus level, garlic skin supplementation altered the ruminal bacterial composition by increasing (P < 0.05) the relative abundances of Prevotella, Bulleidia, Howardella, and Methanosphaera and decreasing (P < 0.05) the abundance of Fretibacterium. Concentrations of 139 metabolites significantly differed (P < 0.05) between the GAS and the CON groups. Among them, substrates for rumen microbial protein synthesis were enriched in the GAS group. The pathways of pyrimidine metabolism, purine metabolism, and vitamin B6 metabolism were influenced (P < 0.05) by garlic skin supplementation. Integrated correlation analysis also provided a link between the significantly altered rumen microbiota and metabolites. Thus, supplementation of garlic skin improved the growth performance of lambs by modifying rumen fermentation through shifts in the rumen microbiome and metabolome.

Long-Term Effects of Dietary Supplementation with Olive Oil and Hydrogenated Vegetable Oil on the Rumen Microbiome of Dairy Cows

Dietary lipids increase energy density in dairy cow diets and in some cases can increase beneficial fatty acids (FA) in milk and dairy products. However, the degree of FA saturation may affect the rumen microbiome. The objective of this study was to determine the long-term effects of feeding saturated (hydrogenated vegetable oil; HVO) or unsaturated (olive oil; OO) fatty acid (FA) sources on the rumen microbiome of dairy cows. For 63 days, 15 mid-lactating cows were fed with either a basal diet (no fat supplement), or the basal diet supplemented with 3% dry matter (DM), either HVO or OO. Rumen contents were collected on days 21, 42 and 63 for 16S rRNA gene sequencing using the Illumina MiSeq platform. The results reveal dominance of the phyla Firmicutes (71.5%) and Bacteroidetes (26.2%), and their respective prevalent genera Succiniclasticum (19.4%) and Prevotella (16.6%). Succiniclasticum increased with both treatments at all time points. Prevotella was reduced on day 42 in both diets. Bacterial diversity alpha or beta were not affected by diets. Predicted bacterial functions by CowPI showed changes in energy and protein metabolism. Overall, 3% DM of lipid supplementation over 63 days can be used in dairy cow diets without major impacts on global bacterial community structure.

Biogas Plant Exploitation in a Middle-Sized Dairy Farm in Poland: Energetic and Economic Aspects

Although cow manure is a valuable natural fertilizer, it is also a source of extreme greenhouse gas emissions, mainly methane. For this reason, this study aims to determine the impact of investments in a biogas plant on the energy and economic aspects of the operation of a dairy farm. A farm with a breeding size of 600 livestock units (LSU) was adopted for the analysis. In order to reach the paper’s aim, the analysis of two different scenarios of dairy farm functioning (conventional–only milk production, and modern–with biogas plant exploitation) was conducted. The analysis showed that the investment in biogas plant operations at a dairy farm and in using cow manure as one of the main substrates is a more profitable scenario compared to traditional dairy farming. Taking into account the actual Polish subsidies for electricity produced by small biogas plants, the scenario with a functioning biogas plant with a capacity of 500 kW brings €332,000/a more profit compared to the conventional scenario, even when taking into account additional costs, including the purchase of straw to ensure a continuous operation of the installation. Besides, in the traditional scenario, building a biogas plant allows for an almost complete reduction of greenhouse gas emissions during manure storage.

The impact of human-facilitated selection on the gut microbiota of domesticated mammals

Domestication is the process by which anthropogenic forces shape lifestyle and behavior of wild species to accommodate human needs. The impact of domestication on animal physiology and behavior has been extensively studied, whereas its effect on the gut microbiota is still largely unexplored. For this reason, 16S rRNA gene-based and internal transcribed spacer-mediated bifidobacterial profiling, together with shotgun metagenomics, was employed to investigate the taxonomic composition and metabolic repertoire of 146 mammalian fecal samples, corresponding to 12 domesticated-feral dyads. Our results revealed that changes induced by domestication have extensively shaped the taxonomic composition of the mammalian gut microbiota. In this context, the selection of microbial taxa linked to a more efficient feed conversion into body mass and putative horizontal transmission of certain bacterial genera from humans were observed in the fecal microbiota of domesticated animals when compared to their feral relatives and to humans. In addition, profiling of the metabolic arsenal through metagenomics highlighted extensive functional adaptation of the fecal microbial community of domesticated mammals to changes induced by domestication. Remarkably, domesticated animals showed, when compared to their feral relatives, increased abundance of specific glycosyl hydrolases, possibly due to the higher intake of complex plant carbohydrates typical of commercial animal feeds.

The use of essential oils as a growth promoter for small ruminants: a systematic review and meta-analysis

Background: Due to their antimicrobial properties and safety, essential oils are currently proposed as a sustainable option for antibiotic alternatives in the livestock sector. This current systematic review and meta-analysis investigated the effects of dietary essential oil supplements on dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR) of small ruminants. Methods: A total of 12 studies (338 small ruminants) were included in this meta-analysis. The overall effect size was quantified using Hedges' g with 95% confidence interval (CI) using a fixed-effect model. Publication bias was inspected using Begg's and Egger's tests, followed by trim and fill method to detect the number of potential missing studies. Results: Insignificant heterogeneity among studies was detected both on DMI ( P of Q = 0.810; I-square = 0.00%), ADG ( P of Q = 0.286; I-square = 17.61%), and FCR ( P of Q = 0.650; I-square = 0.00%). The overall effect size showed that essential oils supplementation had no significant impact on DMI (Hedges' g = -0.12; 95% CI = -0.50 to 0.26; P = 0.429) and FCR (Hedges' g = -0.17; 95% CI = -0.55 to 0.22; P = 0.284), but had a significant positive impact on ADG (Hedges' g = 0.44; 95% CI = 0.12 to 0.76; P = 0.002). The result of publication bias analysis showed that DMI, ADG, and FCR did not present any significant biases ( P > 0.10), and no potential missing studies detected. Conclusions: Dietary essential oil could improve ADG of small ruminants, without any alteration on DMI and FCR. Further research in this topic is still required to provide stronger evidence of the potency of essential oil as a growth promoter for small ruminants.

The use of essential oils as a growth promoter for small ruminants: a systematic review and meta-analysis

Background: Due to their antimicrobial properties and safety, essential oils are currently proposed as a sustainable option for antibiotic alternatives in the livestock sector. This current systematic review and meta-analysis investigated the effects of dietary essential oil supplements on dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR) of small ruminants.

Methods: A total of 12 studies (338 small ruminants) were included in this meta-analysis. The overall effect size was quantified using Hedges’ g with 95% confidence interval (CI) using a fixed-effect model. Publication bias was inspected using Begg’s and Egger’s tests, followed by trim and fill method to detect the number of potential missing studies.

Results: Insignificant heterogeneity among studies was detected both on DMI ( P of Q = 0.810; I-square = 0.00%), ADG ( P of Q = 0.286; I-square = 17.61%), and FCR ( P of Q = 0.650; I-square = 0.00%). The overall effect size showed that essential oils supplementation had no significant impact on DMI (Hedges’ g = -0.12; 95% CI = -0.50 to 0.26; P = 0.429) and FCR (Hedges’ g = -0.17; 95% CI = -0.55 to 0.22; P = 0.284), but had a significant positive impact on ADG (Hedges’ g = 0.44; 95% CI = 0.12 to 0.76; P = 0.002). The result of publication bias analysis showed that DMI, ADG, and FCR did not present any significant biases ( P > 0.10), and no potential missing studies detected.

Conclusions: Dietary essential oil could improve ADG of small ruminants, without any alteration on DMI and FCR. Further research in this topic is still required to provide stronger evidence of the potency of essential oil as a growth promoter for small ruminants.

Identification of Complex Rumen Microbiome Interaction Within Diverse Functional Niches as Mechanisms Affecting the Variation of Methane Emissions in Bovine

A network analysis including relative abundances of all ruminal microbial genera (archaea, bacteria, fungi, and protists) and their genes was performed to improve our understanding of how the interactions within the ruminal microbiome affects methane emissions (CH4). Metagenomics and CH4 data were available from 63 bovines of a two-breed rotational cross, offered two basal diets. Co-abundance network analysis revealed 10 clusters of functional niches. The most abundant hydrogenotrophic Methanobacteriales with key microbial genes involved in methanogenesis occupied a different functional niche (i.e., "methanogenesis" cluster) than methylotrophic Methanomassiliicoccales (Candidatus Methanomethylophylus) and acetogens (Blautia). Fungi and protists clustered together and other plant fiber degraders like Fibrobacter occupied a seperate cluster. A Partial Least Squares analysis approach to predict CH4 variation in each cluster showed the methanogenesis cluster had the best prediction ability (57.3%). However, the most important explanatory variables in this cluster were genes involved in complex carbohydrate degradation, metabolism of sugars and amino acids and Candidatus Azobacteroides carrying nitrogen fixation genes, but not methanogenic archaea and their genes. The cluster containing Fibrobacter, isolated from other microorganisms, was positively associated with CH4 and explained 49.8% of its variability, showing fermentative advantages compared to other bacteria and fungi in providing substrates (e.g., formate) for methanogenesis. In other clusters, genes with enhancing effect on CH4 were related to lactate and butyrate (Butyrivibrio and Pseudobutyrivibrio) production and simple amino acids metabolism. In comparison, ruminal genes negatively related to CH4 were involved in carbohydrate degradation via lactate and succinate and synthesis of more complex amino acids by γ-Proteobacteria. When analyzing low- and high-methane emitters data in separate networks, competition between methanogens in the methanogenesis cluster was uncovered by a broader diversity of methanogens involved in the three methanogenesis pathways and larger interactions within and between communities in low compared to high emitters. Generally, our results suggest that differences in CH4 are mainly explained by other microbial communities and their activities rather than being only methanogens-driven. Our study provides insight into the interactions of the rumen microbial communities and their genes by uncovering functional niches affecting CH4, which will benefit the development of efficient CH4 mitigation strategies.

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.

Effect of Dried Leaves of Leucaena leucocephala on Rumen Fermentation, Rumen Microbial Population, and Enteric Methane Production in Crossbred Heifers

The effects of dietary inclusion of dried Leucaena leucocephala leaves (DLL) on nutrient digestibility, fermentation parameters, microbial rumen population, and production of enteric methane (CH₄) in crossbred heifers were evaluated. Four heifers were used in a 4 × 4 Latin square design consisting of four periods and four levels of inclusion of DLL: 0%, 12%, 24%, and 36% of dry matter (DM) intake. Results showed that DM intake (DMI), organic matter intake, and gross energy intake (GEI) were similar (p > 0.05) among treatments. Apparent digestibility of organic matter, neutral detergent fiber, and energy decreased with increasing levels of DLL in the ration (p < 0.05). In contrast, digestible crude protein (CP) was higher (p < 0.05) in treatments with 12% and 24% DM of DLL. The inclusion of DLL did not affect (p > 0.05) rumen pH and total volatile fatty acids. Rumen microbial community was not affected (p > 0.05) by treatment. There was a linear reduction (p < 0.05) in CH₄ emissions as the levels of DLL in the ration were increased. Results of this study suggest that an inclusion of 12% DM of ration as DLL enhances digestible CP and reduces daily production of enteric CH₄ without adversely affecting DMI, rumen microbial population, and fermentation parameters.

Gas Production, Digestibility and Efficacy of Stored or Fresh Plant Extracts to Reduce Methane Production on Different Substrates

Simple Summary

Medicinal plants possess the ability to mitigate methane production from ruminants. Long-term stability of these plant extracts are essential qualities to be able to replace other rumen modifiers. After one year of storage, plant secondary metabolites used in this study reduced methane production from low-quality forages, without adverse effects on feed digestibility in vitro.

Abstract

Natural compounds such as plant secondary metabolites (PSM) can be used to replace antibiotic growth promoters as rumen modifiers. In this study, the effectiveness of stored and freshly extracted Aloe vera (AV), Azadirachta indica (AZ), Moringa oleifera (MO), Jatropha curcas (JA), Tithonia diversifolia (TD) and Carica papaya (CP) crude extract and monensin on in vitro gas and methane production, organic matter digestibility (IVOMD) and volatile fatty acids (VFA) were evaluated using a total mixed ration (TMR), lucerne or Eragrostis curvula substrates. Fresh extracts were processed from the same batch of frozen (−20 °C) plant material a few days before the trial while the stored extracts were extracted and stored at 4 °C for 12 months prior to the study. Extraction was done by solubilising 50 g freeze-dried plant material in 500 mL 100% methanol. Four mL of reconstituted 50 mg crude extract per 1000 mL distilled water was added per incubation vial, which already contained 400 mg substrate and in vitro fermentation, and gas production and IVOMD evaluation were carried out using standard procedures. Results showed that storing plant extracts for 12 months did not affect the activity or stability of metabolites present in the crude extracts, as shown by the lack of differences in total gas production (TGP) and methane produced between fresh or stored extracts across the substrates. In the TMR substrate, plant extracts increased IVOMD but did not affect TGP and methane production, whereas monensin did not have any effect. Plant extracts increased IVOMD of Eragrostis substrate and supressed methane production to a greater extent than monensin (p < 0.05). It can be concluded that storing plant extracts for up to 12 months did not compromise their efficacy. In addition, the use of 50 mg/kg of AV, AZ, MO, JA, TD and CP extract to a forage-based diet will reduce methane production while improving feed digestibility.

Effect of molasses based multi-nutrient herbal supplements on hematobiochemicals, serum lipid, antioxidants and hormonal profile in buffalo calves

Effect of molasses based multinutrients herbal supplements (MMS) containing ground fenugreek seed and deoiled mahua seed cake at two different ratios (1:1; MMS-I or 1:3; MMS-II) on hematobiochemicals, serum lipid, antioxidants and hormonal profile in male buffalo calves was assessed for 9 months. Fifteen male Murrah buffalo calves (10 to 15 months of age and mean body wt. 234–236 kg) were randomly distributed into 3 groups (5 each) according to Randomized Block Design (RBD). All animals were fed individually with conventional concentrate mixture, available green fodder (3–4 kg DM/d) and wheat straw ad lib. to meet out nutrients requirement. While animals in control group (C) were fed no supplement but animal’s diet in group T1 and T2 supplemented with MMS-I and MMS-II, respectively at 44 g/100 kg body weight or 200 g /100 kg metabolic body weight (kgW0.75). The values of Hb, PCV, RBC, WBC, platelets count, serum total protein, uric acid, creatinine, urea level, total cholesterol, triglyceride, high density lipoprotein (HDL) and T3 hormone level were comparable among 3 groups. Serum glucose, globulin, antioxidants and testosterone levels were significantly increased but serum albumin, A/G ratio, low density lipoprotein (LDL) and cortisol levels were significantly decreased among supplemented groups as compared to control group and hormone T4 was significantly higher in T1 group. The results showed that supplementation of MMS-I and MMS- II in the diet of buffalo calves improved serum glucose, globulin, antioxidants, T4 and testosterone levels but lower albumin, A/G ratio, LDL and cortisol.

Which Diet Has the Least Environmental Impact on Our Planet? A Systematic Review of Vegan, Vegetarian and Omnivorous Diets

The food that we consume has a large impact on our environment. The impact varies significantly between different diets. The aim of this systematic review is to address the question: Which diet has the least environmental impact on our planet? A comparison of a vegan, vegetarian and omnivorous diets. This systematic review is based on 16 studies and 18 reviews. The included studies were selected by focusing directly on environmental impacts of human diets. Four electronic bibliographic databases, PubMed, Medline, Scopus and Web of Science were used to conduct a systematic literature search based on fixed inclusion and exclusion criteria. The durations of the studies ranged from 7 days to 27 years. Most were carried out in the US or Europe. Results from our review suggest that the vegan diet is the optimal diet for the environment because, out of all the compared diets, its production results in the lowest level of GHG emissions. Additionally, the reviewed studies indicate the possibility of achieving the same environmental impact as that of the vegan diet, without excluding the meat and dairy food groups, but rather, by reducing them substantially.

A nutritional and rumen ecological evaluation of the biorefinery by-product alfalfa silage cake supplemented with Scrophularia striata extract using the rumen simulation technique

BACKGROUND

By-products of the food production chain are gaining importance as feedstuffs for ruminants. Alfalfa silage cake (AC) is an unexploited biorefinery by-product rich in fiber. The aim of this study was to test AC, using an in vitro rumen simulation technique (Rusitec), for its suitability as a fiber source for cattle. Three diets with similar crude protein (CP) content were formulated; they contained the biorefinery by-product AC, the original alfalfa silage (OA), or a fiber-rich hay. As fibrous feedstuffs are known to promote ruminal methanogenesis, we additionally tested a plant extract of Scrophularia striata (60 mg g^-1 dry matter) for its methane mitigation and antimicrobial properties.

RESULTS

Diets containing AC displayed lower nutrient degradability, with the largest difference in CP degradation (P < 0.001). Sequencing of microbial DNA revealed several effects of the diet and of the addition of S. striata extract, but no inhibitory effect on methanogens. Likewise, methane production, which, in general, is lower with AC and OA diets, was not inhibited by S. striata extract, while the short chain fatty acid (SCFA) profiles were unaffected.

CONCLUSION

Although CP degradation of the AC diet was lower, degradation of the fiber fractions was similar among diets. According to the present results, AC can be used as fibrous feedstuff for ruminants. Supplementation with S. striata extract did not inhibit methane formation. © 2019 Society of Chemical Industry.

Efficiency and Carbon Footprint of the German Meat Supply Chain

Meat production and consumption contribute significantly to environmental impacts such as greenhouse gas (GHG) emissions. These emissions can be reduced via various strategies ranging from production efficiency improvement to process optimization, food waste reduction, trade pattern change, and diet structure change. On the basis of a material flow analysis approach, we mapped the dry matter mass and energy balance of the meat (including beef, pork, and poultry) supply chain in Germany and discussed the emission reduction potential of different mitigation strategies in an integrated and mass-balance consistent framework. Our results reaffirmed the low energy conversion efficiency of the meat supply chain (among which beef was the least efficient) and the high GHG emissions at the meat production stage. While diet structure change (either reducing the meat consumption or substituting meat by edible offal) showed the highest emissions reduction potential, eliminating meat waste in retailing and consumption and byproducts generation in slaughtering and processing were found to have profound effect on emissions reduction as well. The rendering of meat byproducts and waste treatment were modeled in detail, adding up to a net environmental benefit of about 5% of the entire supply chain GHG emissions. The combined effects based on assumed high levels of changes of important mitigation strategies, in a rank order considering the level of difficulty of implementation, showed that the total emission could be reduced by 43% comparing to the current level, implying a tremendous opportunity for sustainably feeding the planet by 2050.

Effects of Antidesma thwaitesianum Muell. Arg. pomace as a source of plant secondary compounds on digestibility, rumen environment, hematology, and milk production in dairy cows

Mao pomace meal (MPM) contains condensed tannins and saponins at 92 and 98 g/kg, respectively, and these substances can be used to manipulate ruminal fermentation in ruminant. Four multiparous lactating Holstein cows with 45 ± 5 days in milk were randomly assigned according to a 4 × 4 Latin square design to receive four different levels of MPM supplementation at 0, 100, 200, and 300 g/head/day, respectively. Cows were fed with concentrate diets at 1:1.5 of concentrate to milk yield ratio and urea-treated (3%) rice straw was fed ad libitum. The results revealed that feed intake, nutrient digestibility, blood urea nitrogen, and hematological parameters were not affected by MPM supplementation (p > 0.05). However, ruminal pH and propionate were increased quadratically (p < 0.05) in cows receiving MPM whereas acetate, acetate to propionate ratio and estimate methane production were decreased (p < 0.05). Supplementation of MPM linearly decreased ruminal ammonia nitrogen and protozoal population at 4 hr postfeeding (p < 0.05). Milk production and milk composition were similar among treatments (p > 0.05). In conclusion, supplementation of MPM at 200 g/head/day could modify ruminal fermentation and reduce methane production without adverse effect on feed intake, digestibility, hematological parameters, and milk production in dairy cows.

New roughage source of Pennisetum purpureum cv. Mahasarakham utilization for ruminants feeding under global climate change

OBJECTIVE

As the climate changes, it influences ruminant's feed intake, nutrient digestibility, rumen methane production and emission. This experiment aimed to evaluate the effect of feeding Sweet grass (Pennisetum purpureum cv. Mahasarakham; SG) as a new source of good quality forage to improve feed utilization efficiency and to mitigate rumen methane production and emission.

METHODS

Four, growing crossbred of Holstein Friesian heifers, 14 months old, were arranged in a 4×4 Latin square design to receive four dietary treatments. Treatment 1 (T1) was rice straw (RS) fed on ad libitum with 1.0% body weight (BW) of concentrate (C) supplementation (RS/1.0C). Treatment 2 (T2) and treatment 3 (T3) were SG, fed on ad libitum with 1.0% and 0.5% BW of concentrate supplementation, respectively (SG/1.0C and SG/0.5C, respectively). Treatment 4 (T4) was total Sweet grass fed on ad libitum basis with non-concentrate supplementation (TSG).

RESULTS

The results revealed that roughage and total feed intake were increased with SG when compared to RS (p<0.01) while TSG was like RS/1.0C treatment. Digestibility of nutrients, nutrients intake, total volatile fatty acids (VFAs), rumen microorganisms were the highest and CH4 was the lowest in the heifers that received SG/1.0C (p<0.01). Total dry matter (DM) feed intake, digestibility and intake of nutrients, total VFAs, NH3-N, bacterial and fungal population of animals receiving SG/0.5C were higher than those fed on RS/1.0C. Reducing of concentrate supplementation with SG as a roughage source increased NH3-N, acetic acid, and fungal populations, but it decreased propionic acid and protozoal populations (p<0.05). However, ruminal pH and blood urea nitrogen were not affected by the dietary treatments (p>0.05).

CONCLUSION

As the results, SG could be a good forage to improve rumen fermentation, decrease methane production and reduced the level of concentrate supplementation for growing ruminants in the tropics especially under global climate change.

Intake, digestibility, growth performance, and enteric methane emission of Brazilian semiarid non-descript breed goats fed diets with different forage to concentrate ratios

The aim of this study was to evaluate the intake, digestibility, growth performance, and enteric methane emissions of Brazilian semiarid non-descript breed goats (NDG) fed diets with different forage:concentrate ratios (100:0, 80:20, 60:40, 40:60, and 20:80) on a dry matter basis. Forty uncastrated male NDG with an average initial body weight of 13.3 kg ± 4.7 kg were distributed in a completely randomized design, with five treatments and eight replications. Ground Tifton-85 hay was used as forage and ground corn and soybean meal were used as concentrate. The sulfur hexafluoride tracer technique was used to measure methane emissions. The intake of dry matter, organic matter, crude protein, and ether extract increased linearly while the intake of neutral detergent fiber decreased linearly as the concentrate proportion increased (P < 0.05). The digestibility of dry matter and organic matter increased while the digestibility of neutral detergent fiber decreased as the concentrate level increased (P < 0.05). There were linear increases in final body weight, total weight gain, average daily gain, and feed efficiency (P < 0.0001). Methane emissions per unit of body weight (ranging from 1.9 to 0.5 g/kg), metabolic body weight (ranging from 3.9 to 1.2 g/kg), and dry matter intake (ranging from 58.8 to 21.9 g/kg) reduced linearly as the concentrate proportion increased (P < 0.01). Decreasing the forage to concentrate ratio in the diet decreased methane emission and increased growth performance of NDG. The 80:20 ratio could be considered more appropriate to reduce methane emissions from NDG, which did not change much at higher levels of concentrate.

Identification, Comparison, and Validation of Robust Rumen Microbial Biomarkers for Methane Emissions Using Diverse Bos Taurus Breeds and Basal Diets

Previous shotgun metagenomic analyses of ruminal digesta identified some microbial information that might be useful as biomarkers to select cattle that emit less methane (CH4), which is a potent greenhouse gas. It is known that methane production (g/kgDMI) and to an extent the microbial community is heritable and therefore biomarkers can offer a method of selecting cattle for low methane emitting phenotypes. In this study a wider range of Bos Taurus cattle, varying in breed and diet, was investigated to determine microbial communities and genetic markers associated with high/low CH4 emissions. Digesta samples were taken from 50 beef cattle, comprising four cattle breeds, receiving two basal diets containing different proportions of concentrate and also including feed additives (nitrate or lipid), that may influence methane emissions. A combination of partial least square analysis and network analysis enabled the identification of the most significant and robust biomarkers of CH4 emissions (VIP > 0.8) across diets and breeds when comparing all potential biomarkers together. Genes associated with the hydrogenotrophic methanogenesis pathway converting carbon dioxide to methane, provided the dominant biomarkers of CH4 emissions and methanogens were the microbial populations most closely correlated with CH4 emissions and identified by metagenomics. Moreover, these genes grouped together as confirmed by network analysis for each independent experiment and when combined. Finally, the genes involved in the methane synthesis pathway explained a higher proportion of variation in CH4 emissions by PLS analysis compared to phylogenetic parameters or functional genes. These results confirmed the reproducibility of the analysis and the advantage to use these genes as robust biomarkers of CH4 emissions. Volatile fatty acid concentrations and ratios were significantly correlated with CH4, but these factors were not identified as robust enough for predictive purposes. Moreover, the methanotrophic Methylomonas genus was found to be negatively correlated with CH4. Finally, this study confirmed the importance of using robust and applicable biomarkers from the microbiome as a proxy of CH4 emissions across diverse production systems and environments.

Linseed Oil Supplementation of Lambs' Diet in Early Life Leads to Persistent Changes in Rumen Microbiome Structure

Diet has been shown to have a significant impact on microbial community composition in the rumen and could potentially be used to manipulate rumen microbiome structure to achieve specific outcomes. There is some evidence that a window may exist in early life, while the microbiome is being established, where manipulation through diet could lead to long-lasting results. The aim of this study was to test the hypothesis that dietary supplementation in early life will have an effect on rumen microbial composition that will persist even once supplementation is ceased. Twenty-seven new-born lambs were allocated to one of three dietary treatments; a control group receiving standard lamb meal, a group receiving lamb meal supplemented with 40 g kg^-1 DM of linseed oil and a group receiving the supplement pre-weaning and standard lamb meal post-weaning. The supplement had no effect on average daily feed intake or average daily weight gain of lambs. Bacterial and archaeal community composition was significantly (p = 0.033 and 0.005, respectively) different in lambs fed linseed oil throughout the study compared to lambs on the control diet. Succinivibrionaceae, succinate producers, and Veillonellaceae, propionate producers, were in a higher relative abundance in the lambs fed linseed oil while Ruminococcaceae, a family linked with high CH₄ emitters, were in a higher relative abundance in the control group. The relative abundance of Methanobrevibacter was reduced in the lambs receiving linseed compared to those that didn’t. In contrast, the relative abundance of Methanosphaera was significantly higher in the animals receiving the supplement compared to animals receiving no supplement (40.82 and 26.67%, respectively). Furthermore, lambs fed linseed oil only in the pre-weaning period had a bacterial community composition significantly (p = 0.015) different to that of the control group, though archaeal diversity and community structure did not differ. Again, Succinivibrionaceae and Veillonellaceae were in a higher relative abundance in the group fed linseed oil pre-weaning while Ruminococcaceae were in a higher relative abundance in the control group. This study shows that lambs fed the dietary supplement short-term had a rumen microbiome that remained altered even after supplementation had ceased.

On-farm feeding interventions to increase milk production in lactating dairy cows

The objective of this study was to investigate the effect of tropical legume (Phaseolus calcaratus) mixed with ruzi grass feeding on the performance of lactating dairy cows. Eighty-eight lactating dairy cows from 22 smallholder dairy farms northeast of Thailand were assigned to respective dietary treatments according to a Randomized Completely Block Design (RCBD). Four cows were selected from each farm and were allocated into two different feeding groups as follows: ruzi grass and P. calcaratus mixed with ruzi grass (1:1 ratio), respectively. All cows were fed with roughage ad libitum with 1:2 ratio of concentrate diet to milk yield. The results revealed that total dry matter intake, ruminal volatile fatty acids, and ammonia nitrogen concentration were enhanced when cows were fed with P. calcaratus mixed with ruzi grass (P < 0.05). Moreover, feeding tropical legume mixed with ruzi grass could increase milk production and milk protein in this study. Importantly, an economical assessment showed that milk income and the profit from milk sale were significantly greater in cows fed the mixture of roughage than those from the non-mixed group. This study concluded that high-quality roughage as tropical legume mixed with ruzi grass at the ratio of 1:1 brought out the remarkable and practical implementation for smallholder dairy farms, and the intervention was practical and deserving of more on-farm intervention.

In vitro evaluation of different varieties of maize fodder for their methane generation potential and digestibility with goat rumen liquor

AIM

To evaluate the methane generation potential and digestibility of different (normal and three high-quality protein maize [HQPM]) varieties of maize fodder with goat rumen liquor in vitro.

MATERIALS AND METHODS

Methane production potential and digestibility of different varieties of maize fodder were tested in in vitro gas production test. Seven varieties of maize, four normal (HTHM 5101, DHM 117, HM 5, and Shaktiman/900 M Gold), and three high-quality protein (HQPM 5, HQPM 7, and HQPM 9/Vivek) were grown in different plots under the same environmental and agro-climatic conditions. Fodders were harvested at 45-50 days of sowing, and the representative samples of fodder from different varieties of maize were collected for analysis. Dried and grinded form of these maize fodder varieties was tested for gas, methane, and digestibility using goat rumen microflora in in vitro gas syringes.

RESULTS

Gas production (ml/g dry matter [DM]) was highest for HM5 variety (97.66, whereas lowest for HQPM 9 variety (64.22). Gas production (ml/g degraded DM [DDM]) and methane (%) were statistically similar in different varieties of maize fodder. The methane production expressed as ml/g DM and ml/g DDM was significantly (p<0.05) highest for HM 5 (14.22 and 26.62) and lowest for DHM 117 variety (7.47 and 14.13). The in vitro DM digestibility (%) and in vitro organic matter digestibility (%) varied from 47.48 (HQPM 5) to 52.05 (HQPM 9) and 50.03 (HQPM 7) to 54.22 (HM 5), respectively.

CONCLUSION

The present study concluded that DHM 117 maize variety fodder has lowest methane generation potential and incorporating it in the dietary regime of ruminants may contribute to lower methane production.

Effect of ground corn cobs as a fiber source in total mixed ration on feed intake, milk yield and milk composition in tropical lactating crossbred Holstein cows

The aim of this study was to evaluate the effect of ground corn cobs (GCC) as a sole fiber source in total mixed ration (TMR) on feed intake, milk yield and milk composition in tropical lactating crossbred Holstein cows. Four multiparous crossbreds Holstein Friesian dairy cows with an initial body weight (BW) of 415.5 ± 26.20 kg were used in a 4 × 4 Latin square design. The dietary treatments of TMR contained a roughage-to-concentrate ratio of 40:60. The roughage source was used at different ratios of GCC to rice straw (RS) at 100:0, 82.5:17.5, 67.5:32.5, and 50:50 for TMR1 to TMR4, respectively. The results revealed significant improvements in intake of dry matter, protein, neutral detergent fiber (NDF) and metabolizable energy (ME) for TMR1 and TMR2 (P < 0.05), while the digestibility of nutrients was not altered by the treatments (P ≥ 0.05). Ground corn cobs was used for up to 100% of the total roughage without affecting milk production. Moreover, ruminal pH, temperature, ammonia-nitrogen (NH₃-N) and volatile fatty acid (VFA) concentrations were not impacted by the treatments (P > 0.05). However, milk yield was significantly different among the GCC:RS ratios (P < 0.05) and was the highest in TMR1 and TMR2 (13.1 kg/d), while the milk compositions were not changed (P > 0.05). The results imply that using GCC as a whole roughage source significantly improved nutrients intake and milk yield in dairy cows raised in tropical areas.

FABP4 is a leading candidate gene associated with residual feed intake in growing Holstein calves

Ecological and economic concerns drive the need to improve feed utilization by domestic animals. Residual feed intake (RFI) is one of the most acceptable measures for feed efficiency (FE). However, phenotyping RFI-related traits is complex and expensive and requires special equipment. Advances in marker technology allow the development of various DNA-based selection tools. To assimilate these technologies for the benefit of RFI-based selection, reliable phenotypic measures are prerequisite. In the current study, we identified single nucleotide polymorphisms (SNPs) associated with RFI phenotypic consistency across different ages and diets (named RFI 1-3), using DNA samples of high or low RFI ranked Holstein calves. Using targeted sequencing of chromosomal regions associated with FE- and RFI-related traits, we identified 48 top SNPs significantly associated with at least one of three defined RFIs. Eleven of these SNPs were harbored by the fatty acid binding protein 4 (FABP4). While 10 significant SNPs found in FABP4 were common for RFI 1 and RFI 3, one SNP (FABP4_5; A<G substitution), in the promoter region of the gene, was significantly associated with all three RFIs. As the three RFI classes reflect changing diets and ages with concomitant RFI phenotypic consistency, the above polymorphisms and in particular FABP4_5, might be considered possible markers for RFI-based selection for FE in the Holstein breed, following a larger-scale validation.