The Effect of Dietary Replacement of Ordinary Rice with Red Yeast Rice on Nutrient Utilization, Enteric Methane Emission and Rumen Archaeal Diversity in Goats

Combined effects of nitrate and medium-chain fatty acids on methane production, rumen fermentation, and rumen bacterial populations in vitro

This study investigated the combined effects of nitrate (NT) and medium-chain fatty acids (MCFA), including C8, C10, C12, and C14, on methane (CH4) production, rumen fermentation characteristics, and rumen bacteria using a 24 h batch incubation technique. Four types of treatments were used: control (no nitrate, no MCFA), NT (nitrate at 3.65 mM), NT + MCFA (nitrate at 3.65 mM + one of the four MCFA at 500 mg/L), and NT + MCFA/MCFA (nitrate at 3.65 mM + a binary combination of MCFA at 250 and 250 mg/L). All treatments decreased (P < 0.001) methanogenesis (mL/g dry matter incubated) compared with the control, but their efficiency was dependent on the MCFA type. The most efficient CH4 inhibitor was the NT + C10 treatment (- 40%). The combinations containing C10 and C12 had the greatest effect on bacterial alpha and beta diversity and relative microbial abundance (P < 0.001). Next-generation sequencing showed that the family Succinivibrionaceae was favored in treatments with the greatest CH4 inhibition at the expense of Prevotella and Ruminococcaceae. Furthermore, the relative abundance of Archaea decreased (P < 0.05) in the NT + C10 and NT + C10/C12 treatments. These results confirm that the combination of NT with MCFA (C10 and C12 in particular) may effectively reduce CH4 production.

Technology for Carbon Neutral Animal Breeding

Animal breeding techniques are to genetically select highly productive animals with less GHG emission intensity, thereby reducing the number of animals required to produce the same amount of food. Shotgun metagenomics provides a platform to identify rumen microbial communities and genetic markers associated with CH4 emissions, allowing the selection of cattle with less CH4 emissions. Moreover, breeding is a viable option to make real progress towards carbon neutrality with a very high rate of return on investment and a very modest cost per tonne of CO2 equivalents saved regardless of the accounting method. Other high technologies include the use of cloned livestock animals and the manipulation of traits by controlling target genes with improved productivity.

Lovastatin as a supplement to mitigate rumen methanogenesis: an overview

Methane from enteric fermentation is the gas with the greatest environmental impact emitted by ruminants. Lovastatin (Lv) addition to feedstocks could be a strategy to mitigate rumen methane emissions via decreasing the population of methanogenic archaea (MA). Thus, this paper provides the first overview of the effects of Lv supplementation, focusing on the inhibition of methane production, rumen microbiota, and ruminal fermentation. Results indicated that Lv treatment had a strong anti-methanogenic effect on pure strains of MA. However, there are uncertainties from in vitro rumen fermentation trials with complex substrates and rumen inoculum.

Solid-state fermentation (SSF) has emerged as a cost-effective option to produce Lv. In this way, SSF of agricultural residues as an Lv-carrier supplement in sheep and goats demonstrated a consistent decrease in ruminal methane emissions. The experimental evidence for in vitro conditions showed that Lv did not affect the volatile fatty acids (VFA). However, in vivo experiments demonstrated that the production of VFA was decreased. Lv did not negatively affect the digestibility of dry matter during in vitro and in vivo methods, and there is even evidence that it can induce an increase in digestibility. Regarding the rumen microbiota, populations of MA were reduced, and no differences were detected in alpha and beta diversity associated with Lv treatment. However, some changes in the relative abundance of the microbiota were induced. Further studies are recommended on: (i) Lv biodegradation products and stability, as well as its adsorption onto the solid matter in the rumen, to gain more insight on the “available” or effective Lv concentration; and (ii) to determine whether the effect of Lv on ruminal fermentation also depends on the feed composition and different ruminants.

Red Yeast Rice: A Systematic Review of the Traditional Uses, Chemistry, Pharmacology, and Quality Control of an Important Chinese Folk Medicine

Red yeast rice (RYR), a Chinese traditional folk medicine produced by the fermentation of cooked rice kernels with a Monascaceae mold, Monascus purpureus, has long been used to treat blood circulation stasis, indigestion, diarrhea, and limb weakness in East Asian countries. This article provides a systematic review of the traditional uses, chemistry, biological activities, and toxicology of RYR to highlight its future prospects in the field of medicine. The literature reviewed for this article was obtained from the Web of Science, Elsevier, SciFinder, PubMed, CNKI, ScienceDirect, and Google Scholar, as well as Ph.D. and M.Sc. dissertations, published prior to July 2019. More than 101 chemical constituents have been isolated from RYR, mainly consisting of monacolins, pigments, organic acids, sterols, decalin derivatives, flavonoids, polysaccharides, and other compounds. Crude extracts of RYR, as well as its isolated compounds, possess broad pharmacological properties with hypolipidemic, anti-atherosclerotic, anti-cancer, neurocytoprotective, anti-osteoporotic, anti-fatigue, anti-diabetic, and anti-hypertensive activities. However, further studies are needed to characterize its diverse chemical constituents and the toxicological actions of the main bioactive compounds. New pharmacological trials addressing the overlooked traditional uses of RYR, such as in the treatment of indigestion and diarrhea, are required.

Monascus spp. used in wheat kernel solid-state fermentations: growth, extrolite production and citrinin cytotoxicity

Monascus fermentation products can be consumed as food or feed supplements or used as food colouring or flavouring agents. In this study, qPCR and Q-TOF LC/MS methods were developed to monitor Monascus ruber and Monascus purpureus growth and extrolite (lovastatin, mevastatin, as well as the regulated mycotoxin, citrinin (CIT)) production, respectively. Wheat kernels were inoculated with one strain of each species during a solid-state fermentation followed over 63 days. Different growth and extrolite production patterns were clearly observed for the 2 tested strains. After 63 days, high lovastatin levels (up to 0.5 mg/g) were reached for M. ruber wheat fermented kernels while M. purpureus only yielded 0.1 mg/g of lovastatin at best, suggesting that M. ruber may be a better candidate for lovastatin production in a wheat-based model. Mevastatin levels were low and stable for both species. However, M. ruber fermented wheat kernels also contained the highest CIT content, up to 4.2 μg/g, i.e. at levels above the regulation threshold set by the European Union. CIT toxicity was then determined in vitro on bovine kidney cells, showing an IC10 of 6.10-4 M. At maximum concentrations encountered during solid-state fermentation, CIT toxicity was very low under chronic exposure.

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.

Relationship between the structure and composition of rumen microorganisms and the digestibility of neutral detergent fibre in goats

OBJECTIVE

This experiment was conducted to compare the structure and composition of ruminal microorganisms in goats with high and low neutral detergent fibre (NDF) digestibility.

METHODS

Nineteen crossbred goats were used as experimental animals and fed the same total mixed rations during the 30-day pre-treatment and 6-day digestion trialperiods. All faeces were collected during the digestion period for measuring the NDF digestibility. Then, high and the low NDF digestibility individuals were chosen for the high NDF digestibility group (HFD) and low NDF digestibility group (LFD), respectively. Rumen contents were collected for total microbial DNA extraction. The V4 region of the bacterial 16S rRNA gene was amplified using universal primers of bacteria and sequenced using high-throughput sequencer. The sequences were mainly analysed by QIIME 1.8.0.

RESULTS

A total of 18,694 operational taxonomic units were obtained, within 81.98% belonged to bacteria, 6.64% belonged to archaea and 11.38% was unassigned microorganisms. Bacteroidetes, Firmicutes, and Proteobacteria were the predominant microbial phyla in both groups. At the genus level, the relative abundance of fifteen microorganisms were significantly higher (p<0.05) and six microorganisms were extremely significantly higher (p<0.01) in LFD than HFD. Overall, 176 core shared genera were identified in the two groups. The relative abundance of 2 phyla, 5 classes, 10 orders, 13 families and 15 genera had a negative correlation with NDF digestibility, but only the relative abundance of Pyramidobacter had a positive correlation with NDF digestibility.

CONCLUSION

There were substantial differences in NDF digestibility among the individual goats, and the NDF digestibility had significant correlation with the relative abundance of some ruminal microorganisms.

Effects of naturally-produced lovastatin on feed digestibility, rumen fermentation, microbiota and methane emissions in goats over a 12-week treatment period

Twenty male Saanen goats were randomly assigned to four levels of lovastatin supplementation and used to determine the optimal dosage and sustainability of naturally produced lovastatin from fermentation of palm kernel cake (PKC) with Aspergillus terreus on enteric methane (CH₄) mitigation. The effects on ruminal microbiota, rumen fermentation, feed digestibility and health of animal were determined over three measuring periods (4-, 8- and 12-weeks) and the accumulation of lovastatin in tissues was determined at the end of the experiment. The diets contained 50% rice straw, 22.8% concentrates and 27.2% of various proportions of untreated or treated PKC to achieve the target daily intake level of 0 (Control), 2, 4 or 6 mg lovastatin/kg body weight (BW). Enteric CH₄ emissions per dry matter intake (DMI), decreased significantly (P<0.05) and equivalent to 11% and 20.4%, respectively, for the 2 and 4 mg/kg BW groups as compared to the Control. No further decrease in CH₄ emission thereafter with higher lovastatin supplementation. Lovastatin had no effect on feed digestibility and minor effect on rumen microbiota, and specifically did not reduce the populations of total methanogens and Methanobacteriales (responsible for CH₄ production). Similarly, lovastatin had little effect on rumen fermentation characteristics except that the proportion of propionate increased, which led to a decreasing trend (P<0.08) in acetic: propionate ratio with increasing dosage of lovastatin. This suggests a shift in rumen fermentation pathway to favor propionate production which serves as H⁺ sink, partly explaining the observed CH₄ reduction. No adverse physiological effects were noted in the animals except that treated PKC (containing lovastatin) was less palatable at the highest inclusion level. Lovastatin residues were detected in tissues of goats fed 6 mg lovastatin/kg BW at between 0.01 to 0.03 μg/g, which are very low.

Aspergillus terreus treated rice straw suppresses methane production and enhances feed digestibility in goats

The objectives of this study were to test the efficacy of producing lovastatin in rice straw treated with Aspergillus terreus in larger laboratory scale following the procedure previously reported and to investigate the effectiveness of the treated rice straw containing lovastatin on methane mitigation in goats. The concentration of lovastatin in the treated rice straw was 0.69 ± 0.05 g/kg dry matter (DM) rice straw. Our results showed that supplementation of lovastatin at 4.14 mg/kg BW reduced methane production by 32% while improving the DM digestibility by 13% (P < 0.05) in goats fed fermented rice straw compared to those fed untreated rice straw. Populations of total methanogens and Methanobacteriales species were significantly reduced (P < 0.05) while the population of total bacteria and Ruminococcus albus were increased in the treatment group (P < 0.05). Our results demonstrated that lovastatin in the treated rice straw acted specifically on the methanogens by inhibiting the activity of HMG-CoA reductase in the methanogens' cell membrane biosynthesis pathway and thus the growth of rumen methanogens as previously reported. This study provides a simple yet practical approach to mitigate enteric methane production particularly in the developing countries which depend heavily on the use of agro-biomass such as rice straw to feed their ruminant animals.

Effects of dietary supplementation of active dried yeast on fecal methanogenic archaea diversity in dairy cows

This study aimed to investigate the effects of dietary supplementation of different dosages of active dried yeast (ADY) on the fecal methanogenic archaea community of dairy cattle. Twelve multiparous, healthy, mid-lactating Holstein dairy cows (body weight: 584 ± 23.2 kg, milk produced: 26.3 ± 1.22 kg/d) were randomly assigned to one of three treatments (control, ADY2, and ADY4) according to body weight with four replicates per treatment. Cows in the control group were fed conventional rations without ADY supplementation, while cows in the ADY2 and ADY4 group were fed rations supplemented with ADY at 2 or 4 g/d/head. Real-time PCR analysis showed the populations of total methanogens in the feces were significantly decreased (P < 0.05) in the ADY4 group compared with control. High-throughput sequencing technology was applied to examine the differences in methanogenic archaea diversity in the feces of the three treatment groups. A total of 155,609 sequences were recovered (a mean of 12,967 sequences per sample) from the twelve fecal samples, which consisted of a number of operational taxonomic units (OTUs) ranging from 1451 to 1,733, were assigned to two phyla, four classes, five orders, five families and six genera. Bioinformatic analyses illustrated that the natural fecal archaeal community of the control group was predominated by Methanobrevibacter (86.9% of the total sequence reads) and Methanocorpusculum (10.4%), while the relative abundance of the remaining four genera were below 1% with Methanosphaera comprising 0.8%, Thermoplasma composing 0.4%, and the relative abundance of Candidatus Nitrososphaera and Halalkalicoccus being close to zero. At the genus level, the relative abundances of Methanocorpusculum and Thermoplasma were increased (P < 0.05) with increasing dosage of ADY. Conversely, the predominant methanogen genus Methanobrevibacter was decreased with ADY dosage (P < 0.05). Dietary supplementation of ADY had no significant effect (P > 0.05) on the abundances of genera unclassified, Candidatus Nitrososphaera, and Halalkalicoccus. In conclusion, supplementation of ADY to the rations of dairy cattle could alter the population sizes and composition of fecal methanogenic archaea in the feces of dairy cattle. The decrease in Methanobrevibacter happened with a commensurate increase in the genera Methanocorpusculum and Thermoplasma.