Quantification of antibiotic resistance genes and mobile genetic in dairy manure

Background Antibiotic resistance genes (ARGs) are considered to be emerging environmental contaminants of concern potentially posing risks to human and animal health, and this research studied the prevalence of antimicrobial resistance in dairy manure. Methods This study is focused on investigating prevalence of ARGs in California dairy farm manure under current common different manure management. A total of 33 manure samples were collected from multiple manure treatment conditions: (1) flushed manure (FM), (2) fresh pile (FP), (3) compost pile (CP), (4) primary lagoon (PL), and (5) secondary lagoon (SL). After DNA extraction, all fecal samples were screened by PCR for the presence of eight ARGs: four sulfonamide ARGs (sulI, sulII, sulIII, sulA), two tetracycline ARGs (tetW, tetO), two macrolide-lincosamide-streptogramin B (MLSB) ARGs (ermB, ermF). Samples were also screened for two mobile genetic elements (MGEs) (intI1, tnpA), which are responsible for dissemination of ARGs. Quantitative PCR was then used to screen all samples for five ARGs (sulII, tetW, ermF, tnpA and intI1). Results Prevalence of genes varied among sample types, but all genes were detectable in different manure types. Results showed that liquid-solid separation, piling, and lagoon conditions had limited effects on reducing ARGs and MGEs, and the effect was only found significant on tetW (p = 0.01). Besides, network analysis indicated that sulII was associated with tnpA (p < 0.05), and Psychrobacter and Pseudomonas as opportunistic human pathogens, were potential ARG/MGE hosts (p < 0.05). This research indicated current different manure management practices in California dairy farms has limited effects on reducing ARGs and MGEs. Improvement of different manure management in dairy farms is thus important to mitigate dissemination of ARGs into the environment.

Inventarisasi potensi emisi metana (CH4) pada peternakan sapi perah di Kecamatan Pujon, Kabupaten Malang

<p class="MDPI17abstract"><strong>Objective: </strong>The methane emissions in ruminants such as dairy cows was one of the causes of climate change. The aimed of this study was to make an inventory of methane emissions from dairy farms in Pujon District. The methane emission data inventory was expected to assist the government in making policies as an effort to mitigation of methane emissions.</p><p class="MDPI17abstract"><strong>Methods: </strong>The secondary data used in this study were obtained from journals, books, literature related to research, and data from the Central Statistics Agency (BPS). Methane emissions was calculated using the Tier 1 method according to IPCC reference. The reason for the inventory using the tier 1 method was caused that the specific data related to emissions on dairy cows in Malang Regency were not available. The data obtained were processed descriptively.<strong></strong></p><p class="MDPI17abstract"><strong>Results</strong><strong>: </strong>The data obtained shown that the population of dairy cows in Pujon District from 2013-2015 has increased, in 2016 it experienced a significant decline, namely 14.2%, then from 2017-2019 it continued to decline. Methane emissions from enteric fermentation from 2013-2019 averaged 23.13 Gg CO₂-eq / year. Methane emissions from manure management in dairy cows in Pujon District from 2013-2019 were an average of 11.75 Gg CO₂-eq / year. The highest methane emissions were in 2015, and the lowest was in 2019.<strong></strong></p><strong>Conclusions: </strong>Based on the results of the study, it can be concluded that methane emissions from dairy cows in Pujon District increased from 2013-2015, there was a significant reduction in emissions in 2016 – 2019. Feeding with balanced nutrients, using ingredients of concentrated and forage containing good nutrients quality is an effort to mitigate methane that can applied by farmers.

Agricultural methane emissions and the potential formitigation

Agriculture is the largest anthropogenic source of methane (CH 4 ), emitting 145 Tg CH 4 y −1 to the atmosphere in 2017. The main sources are enteric fermentation, manure management, rice cultivation and residue burning. There is significant potential to reduce CH 4 from these sources, with bottom-up mitigation potentials of approximately 10.6, 10, 2 and 1 Tg CH 4 y −1 from rice management, enteric fermentation, manure management and residue burning. Other system-wide studies have assumed even higher potentials of 4.8–47.2 Tg CH 4 y −1 from reduced enteric fermentation, and 4–36 Tg CH 4 y −1 from improved rice management. Biogas (a methane-rich gas mixture generated from the anaerobic decomposition of organic matter and used for energy) also has the potential to reduce unabated CH 4 emissions from animal manures and human waste. In addition to these supply side measures, interventions on the demand-side (shift to a plant-based diet and a reduction in total food loss and waste by 2050) would also significantly reduce methane emissions, perhaps in the order of greater than 50 Tg CH 4 y −1 . While there is a pressing need to reduce emissions of long-lived greenhouse gases (CO 2 and N 2 O) due to their persistence in the atmosphere, despite CH 4 being a short-lived greenhouse gas, the urgency of reducing warming means we must reduce any GHG emissions we can as soon as possible. Because of this, mitigation actions should focus on reducing emissions of all the three main anthropogenic greenhouse gases, including CH 4 . This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part1)'.

Life Cycle Assessment of Sustainable Broiler Production Systems: Effects of Low-Protein Diet and Litter Incineration

We conducted a life cycle assessment (LCA) to compare environmental impacts of conventional (CNV) broiler chicken production in Japan with those of three mitigation options: a low-protein diet supplemented with more crystalline amino acids (LP), incineration of broiler litter (IC), and their combination (LP + IC). Feed production, feed transport, broiler housing, and manure management were included in the LCA, with 1 kg of liveweight of broiler chicken as the functional unit. The CNV environmental impacts were: climate change, 1.86 kg CO2e; acidification, 52.6 g SO2e; eutrophication, 18.3 g PO4e; energy consumption, 18.8 MJ. Since broiler manure management has a lower N2O emission factor, the LP diet’s effects on greenhouse gas (GHG) emissions were limited. Because a large amount of ammonia is emitted from broiler-litter composting and the LP diet reduced nitrogen excretion and consequent NH3 emission, the LP showed lower acidification and eutrophication potentials than CNV. The IC system reduced fuel consumption by utilizing the generated heat for broiler-house heating and thus had lower GHG emissions and energy consumption; it reduced ammonia emission from the manure-management process by incineration and thus had lower acidification and eutrophication potentials even when including NOX generation by litter incineration. The LP + IC system had lower environmental impacts than CNV: for climate change (by 16%), acidification (48%), eutrophication (24%), and energy consumption (15%). Mitigation opportunities for broiler chickens remain, and broiler production systems with mitigation options help produce chickens more sustainably.