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Journal of Dairy Science Nov 2022Recently, many studies have assessed the carbon footprint of bovine milk production. However, due to the complexity of life cycle assessment, most studies have analyzed...
Recently, many studies have assessed the carbon footprint of bovine milk production. However, due to the complexity of life cycle assessment, most studies have analyzed research farms or "representative" farms, which do not capture farm variability. Furthermore, the lack of consistency in most studies means that we can seldom compare the footprint between different countries. To address this issue, we performed a systematic review of the literature, removing inconsistencies in life cycle assessment papers, namely the functional unit, allocation to milk, and global warming potential. We analyzed papers that accounted for many farms to address the variability of production systems within the countries. We found 21 papers from 19 countries; footprint recalculations were necessary for 16 papers. New Zealand, Uruguay, the United Kingdom, Australia, and the United States had a footprint <1 kg of carbon dioxide equivalents (COe) per kilogram of fat- and protein-corrected milk, whereas 5 countries had a footprint >2 kg COe·kg fat- and protein-corrected milk. The change in functional unit resulted in a small effect on the final footprint, whereas the global warming potential change was dependent in on the greenhouse gas profile for each country. Countries where milk is produced mainly as a pasture-based system had most of their footprint (>50%) associated with the emission of methane from enteric fermentation, whereas other countries (especially from Europe and North America) had a significant share of emissions from manure management, feed production, and fertilizer use. This different greenhouse gas profile allow decision makers to tailor mitigation options specific for each country. The choice of the allocation method had a strong influence in the final footprint. We suggest that for future studies, authors adhere to the International Dairy Federation guidelines. When this is not possible, we suggest a set of extra information to be reported, allowing recalculations as done in this review.
Topics: Cattle; United States; Animals; Carbon Footprint; Greenhouse Gases; Dairying; Milk; Farms; Greenhouse Effect
PubMed: 36241436
DOI: 10.3168/jds.2022-22117 -
Environmental Toxicology and Chemistry Dec 2022Industries such as unconventional natural gas have seen increased global expansion to meet the increasing energy needs of our increasing global population.... (Review)
Review
Industries such as unconventional natural gas have seen increased global expansion to meet the increasing energy needs of our increasing global population. Unconventional gas uses hydraulic fracturing that produces significant volumes of produced waters, which can be highly saline and pose a toxic threat to freshwater invertebrates if exposure via discharges, spills, leaks, or runoff were to occur. The primary aim of the present review was to determine the sodium (Na ) and chloride (Cl ) content of these waters as an approximate measure of salinity and how these values compare to the NaCl or synthetic marine salt acute toxicity values of freshwater invertebrate taxa. Shale gas produced waters are much more saline with 78 900 ± 10 200 NaCl mg/L and total dissolved solids (TDS) of 83 200 ± 12 200 mg/L compared to coal bed methane (CBM) produced waters with 4300 ± 1100 NaCl mg/L and TDS of 5900 ± 1300 mg/L and pose a far greater toxicity risk from NaCl to freshwater invertebrates. In addition, the toxicity of other major ions (Ca , K , Mg , , HCO , and ) and their influence on the toxicity of Na and Cl were evaluated. Exposure of untreated and undiluted shale gas produced waters to freshwater invertebrates is likely to result in significant or complete mortality. Shale gas produced waters have higher concentrations of various metals compared with CBM produced waters and are more acidic. We recommend future research to increase the reporting and consistency of water quality parameters, metals, and particularly organics of produced waters to provide a better baseline and help in further investigations. Environ Toxicol Chem 2022;41:2928-2949. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Topics: Animals; Fresh Water; Invertebrates; Natural Gas; Salinity; Sodium Chloride; Water Pollutants, Chemical
PubMed: 36193756
DOI: 10.1002/etc.5492 -
Veterinary and Animal Science Dec 2021Methane (CH) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity... (Review)
Review
Methane (CH) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The 'meta' package in R statistical software was used to conduct the meta-analyses. The covariates defined in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH mitigation . A negative relationship was observed between the level of inclusion and CH emission (-0.09), which means that the effect of CH mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH production will be obtained when supplementing tropical plants in the diet with a high dose of tannins.
PubMed: 34841126
DOI: 10.1016/j.vas.2021.100214 -
Gut Microbes 2021Several studies reported a potential role of methane producing archaea in the pathophysiology of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). We... (Meta-Analysis)
Meta-Analysis
Several studies reported a potential role of methane producing archaea in the pathophysiology of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). We conducted a systematic review and meta-analysis to assess the prevalence of methane positive small intestinal bacterial overgrowth (SIBO) in IBS and IBD compared with controls. MEDLINE (PubMed) and Embase electronic databases were searched from inception until March 2021 for case-control and prevalence studies reporting SIBO in IBS and IBD. We extracted data from published studies and calculated pooled prevalence of SIBO in IBS or IBD, odds ratios (OR), and 95% CIs, utilizing a random effects model. The final dataset included 17 independent studies assessing the prevalence of methane positive SIBO in 1,653 IBS-patients and 713 controls, and 7 studies assessing the prevalence of methane positive SIBO in 626 IBD-patients and 497 controls, all utilizing breath test for SIBO diagnosis. Prevalence of methane positive SIBO in IBS and IBD was 25.0% (95% CI 18.8-32.4) and 5.6% (95% CI 2.6-11.8), respectively. Methane positive SIBO in IBS was not increased compared to controls (OR = 1.2, 95% CI 0.8-1.7, = .37) but was significantly more prevalent in IBS-C as compared to IBS-D (OR = 3.1, 95% CI 1.7-5.6, = .0001). The prevalence of methane-positive SIBO in patients with IBD was 3-fold lower at 7.4% (95% CI 5.4-9.8) compared to 23.5% (95% CI 19.8-27.5) in controls. The prevalence of methane positive SIBO was significantly lower in Crohn's disease as compared to ulcerative colitis, (5.3%, 95% CI 3.0-8.5 vs. 20.2%, 95% CI 12.8-29.4). This systematic review and meta-analysis suggests methane positivity on breath testing is positively associated with IBS-C and inversely with IBD. However, the quality of evidence is low largely due to clinical heterogeneity of the studies. Thus, causality is uncertain and further studies are required.
Topics: Bacteria; Breath Tests; Case-Control Studies; Female; Humans; Inflammatory Bowel Diseases; Intestine, Small; Irritable Bowel Syndrome; Male; Methane
PubMed: 34190027
DOI: 10.1080/19490976.2021.1933313 -
Environmental Pollution (Barking, Essex... Feb 2021Rice paddies are one of the largest greenhouse gases (GHGs) facilitators that are predominantly regulated by nitrogen (N) fertilization. Optimization of N uses based on...
Rice paddies are one of the largest greenhouse gases (GHGs) facilitators that are predominantly regulated by nitrogen (N) fertilization. Optimization of N uses based on the yield has been tried a long since, however, the improvement of the state-of-the-art technologies and the stiffness of global warming need to readjust N rate. Albeit, few individual studies started to, herein attempted as a systematic review to generalize the optimal N rate that minimizes global warming potential (GWP) concurrently provides sufficient yield in the rice system. To satisfy mounted food demand with inadequate land & less environmental impact, GHGs emissions are increasingly evaluated as yield-scaled basis. This systematic review (20 published studies consisting of 21 study sites and 190 observations) aimed to test the hypothesis that the lowest yield-scaled GWP would provide the minimum GWP of CH and NO emissions from rice system at near optimal yields. Results revealed that there was a strong polynomial quadratic relationship between CH emissions and N rate and strong positive correlation between NO emissions and N rate. Compared to control the low N dose emitted less (23%) CH whereas high N dose emitted higher (63%) CH emission. The highest NO emission observed at moderated N level. In total GWP, about 96% and 4%, GHG was emitted as CH and NO, respectively. The mean GWP of CH and NO emissions from rice was 5758 kg CO eq ha. The least yield-scaled GWP (0.7565 (kg CO eq. ha)) was recorded at 190 kg N ha that provided the near utmost yield. This dose could be a suitable dose in midseason drainage managed rice systems especially in tropical and subtropical climatic conditions. This yield-scaled GWP supports the concept of win-win for food security and environmental aspects through balancing between viable rice productivity and maintaining convincing greenhouse gases.
Topics: Agriculture; Global Warming; Methane; Nitrogen; Nitrous Oxide; Oryza; Soil
PubMed: 33388675
DOI: 10.1016/j.envpol.2020.116386 -
Vaccines Aug 2020Ruminants produce considerable amounts of methane during their digestive process, which makes the livestock industry as one of the largest sources of anthropogenic... (Review)
Review
Ruminants produce considerable amounts of methane during their digestive process, which makes the livestock industry as one of the largest sources of anthropogenic greenhouse gases. To tackle this situation, several solutions have been proposed, including vaccination of ruminants against microorganisms responsible for methane synthesis in the rumen. In this review, we summarize the research done on this topic and describe the state of the art of this strategy. The different steps implied in this approach are described: experimental design, animal model (species, age), antigen (whole cells, cell parts, recombinant proteins, peptides), adjuvant (Freund's, Montanide, saponin, among others), vaccination schedule (booster intervals and numbers) and measurements of treatment success (immunoglobulin titers and/or effects on methanogens and methane production). Highlighting both the advances made and knowledge gaps in the use of vaccines to inhibit ruminant methanogen activity, this research review opens the door to future studies. This will enable improvements in the methodology and systemic approaches so as to ensure the success of this proposal for the sustainable mitigation of methane emission.
PubMed: 32825375
DOI: 10.3390/vaccines8030460 -
Efficacy of drugs in chronic idiopathic constipation: a systematic review and network meta-analysis.The Lancet. Gastroenterology &... Nov 2019There are several drugs available for the treatment of chronic idiopathic constipation, but their relative efficacy is unclear because there have been no head-to-head... (Meta-Analysis)
Meta-Analysis
BACKGROUND
There are several drugs available for the treatment of chronic idiopathic constipation, but their relative efficacy is unclear because there have been no head-to-head randomised controlled trials. We did a network meta-analysis to compare the efficacy of these therapies in patients with chronic idiopathic constipation.
METHODS
We searched Medline, Embase, Embase Classic, and the Cochrane Central Register of Controlled Trials for randomised controlled trials published from inception to week 3 June, 2019, to identify randomised controlled trials assessing the efficacy of drugs (osmotic or stimulant laxatives, elobixibat, linaclotide, lubiprostone, mizagliflozin, naronapride, plecanatide, prucalopride, tegaserod, tenapanor, or velusetrag) in adults with chronic idiopathic constipation. Participants had to be treated for a minimum of 4 weeks, and we extracted data for all endpoints preferentially at 4 weeks, 12 weeks, or both. Trials included in the analysis reported a dichotomous assessment of overall response to therapy (response or no response to therapy). We pooled the data using a random effects model, and reported efficacy and safety of all treatments as a pooled relative risk (RR) with 95% CIs to summarise the effect of each comparison tested. To rank treatments, we used P-scores, which measure the extent of certainty that a treatment is better than another treatment, averaged over all competing treatments.
FINDINGS
We identified 33 eligible randomised controlled trials of drugs, comprising 17 214 patients. Based on an endpoint of failure to achieve three or more complete spontaneous bowel movements (CSBMs) per week, the stimulant diphenyl methane laxatives bisacodyl and sodium picosulfate, at a dose of 10 mg once daily, were ranked first at 4 weeks (RR 0·55, 95% CI 0·48-0·63, P-score 0·99), and prucalopride 2 mg once daily ranked first at 12 weeks (0·82, 0·78-0·86, P-score 0·96). When response to therapy was defined as falilure to achieve an increase of one or more CSBM per week from baseline, diphenyl methane laxatives at a dose of 10 mg once daily ranked first at 4 weeks (0·44, 0·37-0·54, P-score 0·99), with prucalopride 4 mg once daily ranked first at 12 weeks (0·74, 0·66-0·83, P-score 0·79), although linaclotide 290 μg once daily and prucalopride 2 mg once daily had similar efficacy (P-scores of 0·76 and 0·71, respectively). Bisacodyl ranked last in terms of safety for total number of adverse events and abdominal pain (P-score 0·08).
INTERPRETATION
Almost all drugs studied were superior to placebo, according to either failure to achieve three or more CSBMs per week or or failure to achieve an increase of one or more CSBM per week over baseline. Although diphenyl methane laxatives ranked first at 4 weeks, patients with milder symptoms might have been included in these trials. Prucalopride ranked first at 12 weeks, and many of the included trials recruited patients who previously did not respond to laxatives, suggesting that this drug is likely to be the most efficacious for patients with chronic idiopathic constipation. However, because treatment duration in most trials was 4-12 weeks, the long-term relative efficacy of these drugs is unknown.
FUNDING
None.
Topics: Constipation; Humans; Laxatives; Randomized Controlled Trials as Topic
PubMed: 31474542
DOI: 10.1016/S2468-1253(19)30246-8