Effects of swine manure dilution with lagoon effluent on microbial communities and odor formation in pit recharge systems.

Pit recharge systems (PRS) control odor by managing organic solids in swine manure. However, there needs to be more understanding of PRS's effect on the microbiome composition and its impact on odor formation. A study was conducted to understand how recharge intervals used in PRS impact manure microbiome and odor formation. Bioreactors dynamically loaded simulated recharge intervals of 14, 10, and 4 days by diluting swine manure with lagoon effluent at varying ratios. Treatment ratios tested included 10:0 (control), 7:3 (typical Korean PRS), 5:5 (enhanced PRS #1), and 2:8 (enhanced PRS #2). Manure microbial membership, chemical concentrations, and odorant concentrations were used to identify the interactions between microbiota, manure, and odor. The initial microbial community structure was controlled by dilution ratio and manure barn source material. Firmicutes and Proteobacteria were the dominant microbial phyla in manure and lagoon effluent, respectively, and significantly decreased or increased with dilution. Key microbial species were Clostridium saudiense in manure and Pseudomonas caeni in lagoon effluent. Percentages of these species declined by 8.9% or increased by 17.6%, respectively, with each unit dilution. Microbial community composition was controlled by both treatment (i.e., manure dilution ratio and barn source material) and environmental factors (i.e., solids and pH). Microbiome composition was correlated with manure odor formation profiles, but this effect was inseparable from environmental factors, which explained over 75% of the variance in odor profiles. Consequently, monitoring solids and pH in recharge waters will significantly impact odor control in PRS.

Damage to medical complexes in the Israel-Hamas war: a geospatial analysis.

INTRODUCTION: Medical facilities are civilian objects specially protected during armed conflict by international humanitarian law (IHL). These protections are customarily applied regardless of the conflict, parties or contexts involved. Attacks on medical care have characterised the bombardment campaign of the Gaza Strip beginning 7 October 2023. This study presents evidence regarding patterns of damage to medical complexes relative to all other buildings in the first month of this conflict. METHODS: This is an observational pre/post-study of damage to buildings during the first month of the Israel Defence Force bombardment of Gaza from 7 October to 7 November 2023. Open-source polygons for the Gaza Strip were spatially joined with building damage assessments from satellite imagery analysis. Medical facilities were included in the analysis if they were cross-referenced by a minimum of two datasets. Welch's t-test was used to test for statistically significant differences in the proportions of damaged medical complexes and other buildings. RESULTS: A total of 167 292 unique buildings were identified, including 106 cross-referenced medical complexes. Approximately 9% of non-medical buildings and medical complexes alike sustained damage during the first month of the bombardment (p>0.7292). CONCLUSION: During the first month of the bombing campaign, evidence suggests medical complexes have not received special protection as required by IHL. This finding raises concerns about combatants' application of the principles of distinction, proportionality and precaution, suggesting the importance of further investigation.

Transparency films: intraoperative templating to prevent limb deformity.

Operative management of fractures and malunions can be challenging when restoring native anatomy is not straightforward. Comminuted fractures and managing deformity correction in the setting of osteolysis, callus, and even complete fracture healing must include careful planning. Preoperative planning has been popularized and taught as an integral part of a surgeon's skill set, with critical evaluation and assessment of the implemented plan being the final step in the process. We present a robust, reproducible, and cost-effective technique for intraoperative fracture fixation assessment with case examples, used routinely at our institution.

Oral administration of helminth fluid modulates distinct tuft cell and immune-metabolic cues linked to reduced body fat.

Intestinal tuft cells have been shown to induce type 2 immune responses during viable parasite infections, but whether oral supplementation with a parasitic exudate is able to promote type 2 immune responses that have been shown to positively regulate obesogenic metabolic processes is yet unresolved. High-fat fed mice were gavaged with pseudocoelomic fluid (PCF) derived from the helminth Ascaris suum or saline thrice a week during weeks 5-9, followed by examination of intestinal tuft cell activity, immune, and metabolic parameters. Helminth PCF upregulated expression of distinct genes in small intestinal tuft cells, including genes involved in regulation of RUNX1 and organic cation transporters. Helminth PCF also enhanced levels of innate lymphoid cells in the ileum, and eosinophils in epididymal white adipose tissue (eWAT). Network analyses revealed two distinct immunometabolic cues affected by oral helminth PCF in high-fat fed mice: one coupling the small intestinal tuft cell responses to the fat-to-lean mass ratio and a second coupling eosinophils in eWAT to general regulation of body fat mass. Our findings point to specific mechanisms by which oral supplementation with helminth PCF may translate into systems-wide effects linking to reduced body and fat mass gain in mice during high-fat feeding.

Nutrient recovery in cultured meat systems: Impacts on cost and sustainability metrics.

A growing global meat demand requires a decrease in the environmental impacts of meat production. Cultured meat (CM) can potentially address multiple challenges facing animal agriculture, including those related to animal welfare and environmental impacts, but existing cost analyses suggest it is hard for CM to match the relatively low costs of conventionally produced meat. This study analyzes literature reports to contextualize CM's protein and calorie use efficiencies, comparing CM to animal meat products' feed conversion ratios, areal productivities, and nitrogen management. Our analyses show that CM has greater protein and energy areal productivities than conventional meat products, and that waste nitrogen from spent media is critical to CM surpassing the nitrogen use efficiency of meat produced in swine and broiler land-applied manure systems. The CM nutrient management costs, arising from wastewater treatment and land application, are estimated to be more expensive than in conventional meat production. Overall, this study demonstrates that nitrogen management will be a key aspect of sustainability in CM production, as it is in conventional meat systems.

Weight loss by calorie restriction does not alter appetite-regulating gut hormone responses from perfused rat small intestine.

AIM: Postprandial secretion of the appetite-inhibiting hormones, glucagon-like peptide-1 (GLP-1), and peptide YY are reduced with obesity. It is unclear if the reduced secretion persists following weight loss (WL), if other appetite-inhibiting hormones are also reduced, and if so whether reduced secretion results from intrinsic changes in the gut. METHODS: To address whether WL may restore secretion of GLP-1 and other appetite-inhibiting hormones, we performed a gut perfusion study of the small intestine in diet-induced obese (DIO) rats after WL. A 20% weight loss (means ± SEM (g): 916 ± 53 vs. 703 ± 35, p < 0.01, n = 7) was induced by calorie restriction, and maintained stable for ≥7 days prior to gut perfusion to allow for complete renewal of enteroendocrine cells. Age-matched DIO rats were used as comparator. Several gut hormones were analyzed from the venous effluent, and gene expression was performed on gut tissue along the entire length of the intestine. RESULTS: Secretion of cholecystokinin, gastrin, glucose-dependent insulinotropic peptide, GLP-1, neurotensin, and somatostatin was not affected by WL during basal conditions (p ≥ 0.25) or in response to macronutrients and bile acids (p ≥ 0.14). Glucose absorption was indistinguishable following WL. The expression of genes encoding the studied peptides, macronutrient transporters (glucose, fructose, and di-/tripeptides) and bile acid receptors did also not differ between DIO and WL groups. CONCLUSIONS: These data suggest that the attenuated postprandial responses of GLP-1, as well as reduced responses of other appetite-inhibiting gut hormones, in people living with obesity may persist after weight loss and may contribute to their susceptibility for weight regain.

Profiling the Atopic Dermatitis Epidermal Transcriptome by Tape Stripping and BRB-seq.

Tape stripping is a non-invasive skin sampling technique, which has recently gained use for the study of the transcriptome of atopic dermatitis (AD), a common inflammatory skin disorder characterized by a defective epidermal barrier and perturbated immune response. Here, we performed BRB-seq-a low cost, multiplex-based, transcriptomic profiling technique-on tape-stripped skin from 30 AD patients and 30 healthy controls to evaluate the methods' ability to assess the epidermal AD transcriptome. An AD signature consisting of 91 differentially expressed genes, specific for skin barrier and inflammatory response, was identified. The gene expression in the outermost layers, stratum corneum and stratum granulosum, of the skin showed highest correlation between tape-stripped skin and matched full-thickness punch biopsies. However, we observed that low and highly variable transcript counts, probably due to low RNA yield and RNA degradation in the tape-stripped skin samples, were a limiting factor for epidermal transcriptome profiling as compared to punch biopsies. We conclude that deep BRB-seq of tape-stripped skin is needed to counteract large between-sample RNA yield variation and highly zero-inflated data in order to apply this protocol for population-wide screening of the epidermal transcriptome in inflammatory skin diseases.

Opposing roles of the entero-pancreatic hormone urocortin-3 in glucose metabolism in rats.

AIM/HYPOTHESIS: Urocortin-3 (UCN3) is a glucoregulatory peptide produced in the gut and pancreatic islets. The aim of this study was to clarify the acute effects of UCN3 on glucose regulation following an oral glucose challenge and to investigate the mechanisms involved. METHODS: We studied the effect of UCN3 on blood glucose, gastric emptying, glucose absorption and secretion of gut and pancreatic hormones in male rats. To supplement these physiological studies, we mapped the expression of UCN3 and the UCN3-sensitive receptor, type 2 corticotropin-releasing factor receptor (CRHR2), by means of fluorescence in situ hybridisation and by gene expression analysis. RESULTS: In rats, s.c. administration of UCN3 strongly inhibited gastric emptying and glucose absorption after oral administration of glucose. Direct inhibition of gastrointestinal motility may be responsible because UCN3's cognate receptor, CRHR2, was detected in gastric submucosal plexus and in interstitial cells of Cajal. Despite inhibited glucose absorption, post-challenge blood glucose levels matched those of rats given vehicle in the low-dose UCN3 group, because UCN3 concomitantly inhibited insulin secretion. Higher UCN3 doses did not further inhibit gastric emptying, but the insulin inhibition progressed resulting in elevated post-challenge glucose and lipolysis. Incretin hormones and somatostatin (SST) secretion from isolated perfused rat small intestine was unaffected by UCN3 infusion; however, UCN3 infusion stimulated secretion of somatostatin from delta cells in the isolated perfused rat pancreas which, unlike alpha cells and beta cells, expressed Crhr2. Conversely, acute antagonism of CRHR2 signalling increased insulin secretion by reducing SST signalling. Consistent with these observations, acute drug-induced inhibition of CRHR2 signalling improved glucose tolerance in rats to a similar degree as administration of glucagon-like peptide-1. UCN3 also powerfully inhibited glucagon secretion from isolated perfused rat pancreas (perfused with 3.5 mmol/l glucose) in a SST-dependent manner, suggesting that UCN3 may be involved in glucose-induced inhibition of glucagon secretion. CONCLUSIONS/INTERPRETATION: Our combined data indicate that UCN3 is an important glucoregulatory hormone that acts through regulation of gastrointestinal and pancreatic functions.

Peptides in the regulation of glucagon secretion.

Glucose homeostasis is maintained by the glucoregulatory hormones, glucagon, insulin and somatostatin, secreted from the islets of Langerhans. Glucagon is the body's most important anti-hypoglycemic hormone, mobilizing glucose from glycogen stores in the liver in response to fasting, thus maintaining plasma glucose levels within healthy limits. Glucagon secretion is regulated by both circulating nutrients, hormones and neuronal inputs. Hormones that may regulate glucagon secretion include locally produced insulin and somatostatin, but also urocortin-3, amylin and pancreatic polypeptide, and from outside the pancreas glucagon-like peptide-1 and 2, peptide tyrosine tyrosine and oxyntomodulin, glucose-dependent insulinotropic polypeptide, neurotensin and ghrelin, as well as the hypothalamic hormones arginine-vasopressin and oxytocin, and calcitonin from the thyroid. Each of these hormones have distinct effects, ranging from regulating blood glucose, to regulating appetite, stomach emptying rate and intestinal motility, which makes them interesting targets for treating metabolic diseases. Awareness regarding the potential effects of the hormones on glucagon secretion is important since secretory abnormalities could manifest as hyperglycemia or even lethal hypoglycemia. Here, we review the effects of each individual hormone on glucagon secretion, their interplay, and how treatments aimed at modulating the plasma levels of these hormones may also influence glucagon secretion and glycemic control.

Expression Profile of the GLP-1 Receptor in the Gastrointestinal Tract and Pancreas in Adult Female Mice.

Therapies based on glucagon-like peptide-1 receptor (GLP-1R) agonism are highly effective in treating type 2 diabetes and obesity, but the localization of GLP-1Rs mediating the antidiabetic and other possible actions of GLP-1 is still debated. The purpose with this study was to identify sites of GLP-1R mRNA and protein expression in the mouse gastrointestinal system by means of GLP-1R antibody immunohistochemistry, Glp1r mRNA fluorescence in situ hybridization, and 125I-exendin (9-39) autoradiography. As expected, GLP-1R staining was observed in almost all ß-cells in the pancreatic islets, but more rarely in α- and δ-cells. In the stomach, GLP-1R staining was found exclusively in the gastric corpus mucous neck cells, known to protect the stomach mucosa. The Brunner glands were strongly stained for GLP-1R, and pretreatment with GLP-1 agonist exendin-4 caused internalization of the receptor and mucin secretion, while pretreatment with phosphate-buffered saline or antagonist exendin (9-39) did not. In the intestinal mucosa, GLP-1R staining was observed in intraepithelial lymphocytes, lamina propria lymphocytes, and enteroendocrine cells containing secretin, peptide YY, and somatostatin, but not cholecystokinin. GLP-1R staining was seen in nerve fibers within the choline acetyl transferase- and nitric oxide-positive myenteric plexuses from the gastric corpus to the distal large intestine being strongest in the mid- and hindgut area. Finally, intraperitoneal administration of radiolabeled exendin (9-39) strongly labeled myenteric fibers. In conclusion, this study expands our knowledge of GLP-1R localization and suggests that GLP-1 may serve an important role in modulating gastrointestinal health and mucosal protection.

Actions of glucagon-like peptide-1 receptor ligands in the gut.

The incretin hormone glucagon-like peptide-1 (GLP-1) is inactivated by the enzyme dipeptidyl peptidase-4 even before it leaves the gut, but it seems to act predominantly via activation of intestinal sensory neurons expressing GLP-1 receptors. Thus, activation of vagal afferents is probably responsible for its effects on appetite and food intake, gastrointestinal secretion and motility, and pancreatic endocrine secretion. However, GLP-1 receptors are widely expressed in the gastrointestinal (GI) tract, including epithelial cells in the stomach, and the Brunner glands, in endocrine cells of the gut epithelium, and on mucosal lymphocytes. In this way, GLP-1 may have important local actions of epithelial protection and endocrine signalling and may interact with the immune system. We review the formation and release of GLP-1 from the endocrine L cells and its fate after release and describe the localization of its receptor throughout the GI tract and discuss its direct or indirect actions in the GI tract. LINKED ARTICLES: This article is part of a themed issue on GLP1 receptor ligands (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.4/issuetoc.

Eubacterium coprostanoligenes and Methanoculleus identified as potential producers of metabolites that contribute to swine manure foaming.

AIM: Swine manure foaming is a major problem, causing damage to property, livestock, and people. Here, we identified the main chemicals and microbes that contribute to foaming. METHODS AND RESULTS: Foaming and non-foaming swine manure were sampled from farms in Iowa and Illinois. Targeted and untargeted metabolomics analyses identified chemical markers that differed between foaming and non-foaming manure and between manure layers. Microbial community analysis and metagenomics were performed on a subset of samples. Foam contained significantly higher levels of total bile acids and long chain fatty acids like palmitic, stearic and oleic acid than the other manure layers. Foam layers also had significantly higher levels of ubiquinone 9 and ubiquinone 10. The slurry layer of foaming samples contained more alanine, isoleucine/leucine, diacylglycerols (DG), phosphtatidylethanolamines, and vitamin K2, while ceramide was significantly increased in the slurry layer of non-foaming samples. Eubacterium coprostanoligenes and Methanoculleus were more abundant in foaming samples, and E. coprostanoligenes was significantly correlated with levels of DG. Genes involved in diacylglycerol biosynthesis and in the biosynthesis of branched-chain hydrophobic amino acids were overrepresented in foaming samples. CONCLUSIONS: A mechanism for manure foaming is hypothesized in which proliferation of Methanoculleus leads to excessive production of methane, while production of DG by E. coprostanoligenes and hydrophobic proteins by Methanosphaera stadtmanae facilitates bubble formation and stabilization. SIGNIFICANCE AND IMPACT OF STUDY: While some chemical and biological treatments have been developed to treat swine manure foaming, its causes remain unknown. We identified key microbes and metabolites that correlate with foaming and point to possible roles of other factors like animal feed.

Acid Hydrolysis of Gluten Enhances the Skin Sensitizing Potential and Drives Diversification of IgE Reactivity to Unmodified Gluten Proteins.

SCOPE: Personal care products containing hydrolyzed gluten have been linked to spontaneous sensitization through the skin, however the impact of the hydrolysate characteristics on the sensitizing capacity is generally unknown. METHODS AND RESULTS: The physicochemical properties of five different wheat-derived gluten products (one unmodified, one enzyme hydrolyzed, and three acid hydrolyzed) are investigated, and the skin sensitizing capacity is determined in allergy-prone Brown Norway rats. Acid hydrolyzed gluten products exhibited the strongest intrinsic sensitizing capacity via the skin. All hydrolyzed gluten products induced cross-reactivity to unmodified gluten in the absence of oral tolerance to wheat, but were unable to break tolerance in animals on a wheat-containing diet. Still, the degree of deamidation in acid hydrolyzed products is associated with product-specific sensitization in wheat tolerant rats. Sensitization to acid hydrolyzed gluten products is associated with a more diverse IgE reactivity profile to unmodified gluten proteins compared to sensitization induced by unmodified gluten or enzyme hydrolyzed gluten. CONCLUSION: Acid hydrolysis enhances the skin sensitizing capacity of gluten and drives IgE reactivity to more gluten proteins. This property of acid hydrolyzed gluten may be related to the degree of product deamidation, and could be a strong trigger of wheat allergy in susceptible individuals.

Bifidobacterium species associated with breastfeeding produce aromatic lactic acids in the infant gut.

Breastfeeding profoundly shapes the infant gut microbiota, which is critical for early life immune development, and the gut microbiota can impact host physiology in various ways, such as through the production of metabolites. However, few breastmilk-dependent microbial metabolites mediating host-microbiota interactions are currently known. Here, we demonstrate that breastmilk-promoted Bifidobacterium species convert aromatic amino acids (tryptophan, phenylalanine and tyrosine) into their respective aromatic lactic acids (indolelactic acid, phenyllactic acid and 4-hydroxyphenyllactic acid) via a previously unrecognized aromatic lactate dehydrogenase (ALDH). The ability of Bifidobacterium species to convert aromatic amino acids to their lactic acid derivatives was confirmed using monocolonized mice. Longitudinal profiling of the faecal microbiota composition and metabolome of Danish infants (n = 25), from birth until 6 months of age, showed that faecal concentrations of aromatic lactic acids are correlated positively with the abundance of human milk oligosaccharide-degrading Bifidobacterium species containing the ALDH, including Bifidobacterium longum, B. breve and B. bifidum. We further demonstrate that faecal concentrations of Bifidobacterium-derived indolelactic acid are associated with the capacity of these samples to activate in vitro the aryl hydrocarbon receptor (AhR), a receptor important for controlling intestinal homoeostasis and immune responses. Finally, we show that indolelactic acid modulates ex vivo immune responses of human CD4+ T cells and monocytes in a dose-dependent manner by acting as an agonist of both the AhR and hydroxycarboxylic acid receptor 3 (HCA3). Our findings reveal that breastmilk-promoted Bifidobacterium species produce aromatic lactic acids in the gut of infants and suggest that these microbial metabolites may impact immune function in early life.

Microbial assemblages and methanogenesis pathways impact methane production and foaming in manure deep-pit storages.

Foam accumulation in swine manure deep-pits has been linked to explosions and flash fires that pose devastating threats to humans and livestock. It is clear that methane accumulation within these pits is the fuel for the fire; it is not understood what microbial drivers cause the accumulation and stabilization of methane. Here, we conducted a 13-month field study to survey the physical, chemical, and biological changes of pit-manure across 46 farms in Iowa. Our results showed that an increased methane production rate was associated with less digestible feed ingredients, suggesting that diet influences the storage pit's microbiome. Targeted sequencing of the bacterial 16S rRNA and archaeal mcrA genes was used to identify microbial communities' role and influence. We found that microbial communities in foaming and non-foaming manure were significantly different, and that the bacterial communities of foaming manure were more stable than those of non-foaming manure. Foaming manure methanogen communities were enriched with uncharacterized methanogens whose presence strongly correlated with high methane production rates. We also observed strong correlations between feed ration, manure characteristics, and the relative abundance of specific taxa, suggesting that manure foaming is linked to microbial community assemblage driven by efficient free long-chain fatty acid degradation by hydrogenotrophic methanogenesis.

Small Intestinal Tuft Cell Activity Associates With Energy Metabolism in Diet-Induced Obesity.

Little is known about the involvement of type 2 immune response-promoting intestinal tuft cells in metabolic regulation. We here examined the temporal changes in small intestinal tuft cell number and activity in response to high-fat diet-induced obesity in mice and investigated the relation to whole-body energy metabolism and the immune phenotype of the small intestine and epididymal white adipose tissue. Intake of high fat diet resulted in a reduction in overall numbers of small intestinal epithelial and tuft cells and reduced expression of the intestinal type 2 tuft cell markers Il25 and Tslp. Amongst >1,700 diet-regulated transcripts in tuft cells, we observed an early association between body mass expansion and increased expression of the gene encoding the serine protease inhibitor neuroserpin. By contrast, tuft cell expression of genes encoding gamma aminobutyric acid (GABA)-receptors was coupled to Tslp and Il25 and reduced body mass gain. Combined, our results point to a possible role for small intestinal tuft cells in energy metabolism via coupled regulation of tuft cell type 2 markers and GABA signaling receptors, while being independent of type 2 immune cell involvement. These results pave the way for further studies into interventions that elicit anti-obesogenic circuits via small intestinal tuft cells.

Systems-wide effects of short-term feed deprivation in obese mice.

While prolonged fasting induces significant metabolic changes in humans and mice, less is known about systems-wide metabolic changes in response to short-term feed deprivation, which is used in experimental animal studies prior to metabolic challenge tests. We here performed a systems biology-based investigation of connections between gut bacterial composition and function, inflammatory and metabolic parameters in the intestine, liver, visceral adipose tissue, blood and urine in high-fat fed, obese mice that were feed deprived up to 12 h. The systems-wide analysis revealed that feed deprivation linked to enhanced intestinal butyric acid production and expression of the gene encoding the pro-thermogenic uncoupling protein UCP1 in visceral adipose tissue of obese mice. Ucp1 expression was also positively associated with Il33 expression in ileum, colon and adipose tissue as well as with the abundance of colonic Porphyromonadaceae, the latter also correlating to cecal butyric acid levels. Collectively, the data highlighted presence of a multi-tiered system of inter-tissue communication involving intestinal, immune and metabolic functions which is affected by feed deprivation in obese mice, thus pointing to careful use of short-feed deprivation in metabolic studies using obese mice.

Using a Reporter Mouse to Map Known and Novel Sites of GLP-1 Receptor Expression in Peripheral Tissues of Male Mice.

Glucagon-like peptide-1 receptor (GLP-1R) activation is used in the treatment of diabetes and obesity; however, GLP-1 induces many other physiological effects with unclear mechanisms of action. To identify the cellular targets of GLP-1 and GLP-1 analogues, we generated a Glp1r.tdTomato reporter mouse expressing the reporter protein, tdTomato, in Glp1r-expressing cells. The reporter signal is expressed in all cells where GLP-1R promoter was ever active. To complement this, we histologically mapped tdTomato-fluorescence, and performed Glp-1r mRNA in situ hybridization and GLP-1R immunohistochemistry on the same tissues. In male mice, we found tdTomato signal in mucus neck, chief, and parietal cells of the stomach; Brunner's glands; small intestinal enteroendocrine cells and intraepithelial lymphocytes; and myenteric plexus nerve fibers throughout the gastrointestinal tract. Pancreatic acinar-, ß-, and δ cells, but rarely α cells, were tdTomato-positive, as were renal arteriolar smooth muscle cells; endothelial cells of the liver, portal vein, and endocardium; aortal tunica media; and lung type 1 and type 2 pneumocytes. Some thyroid follicular and parafollicular cells displayed tdTomato expression, as did tracheal cartilage chondrocytes, skin fibroblasts, and sublingual gland mucus cells. In conclusion, our reporter mouse is a powerful tool for mapping known and novel sites of GLP-1R expression in the mouse, thus enhancing our understanding of the many target cells and effects of GLP-1 and GLP-1R agonists.

Swine manure dilution with lagoon effluent impact on odor reduction and manure digestion.

Manure management systems have a major impact on odor from swine operations. A study was conducted to compare deep-pit manure management systems to flushing barn manure management systems for odor reduction and organic matter degradation. Bioreactors were used to mimic manure management systems in which manure and lagoon effluent were loaded initially, and subsequent manure was added daily at 5% of its storage capacity (1 L). Final manure-to-lagoon effluent ratios were 10:0 (deep-pit manure management system), 7:3 (Korean flushing systems), 5:5 (enhanced flushing systems), and 2:8 (enhanced flushing systems). At the end of the trial, at 4 (2:8), 10 (5:5), or 14 (10:0, 7:3) d, manure and gas concentrations of odorants were measured, including total solids (TS), total N (TN), and total C (TC) of manure. Odor was evaluated using the odor activity values (OAVs), and regression analysis was used to determine the effects of dilution and TS on manure properties and OAVs. Solids in the manure were positively correlated to TN, TC, straight chain fatty acids (SCFAs), branch chain fatty acids (BCFAs), total phenols, and total indoles and positively correlated to OAV for SCFAs, BCFAs, ammonia, total phenols, and total indoles. Reducing TS by 90% reduced BCFA, ammonia, phenols, and indoles by equal amounts in air. Carbon dioxide was the main C source evolved, averaging over 90%, and CH4 increased with dilution quadratically. Overall, reducing solids in manure by dilution had the biggest impact on reducing odor and increasing organic C degradation.

Midwestern cropping system effects on drainage water quality and crop yields.

Grain producers are challenged to maximize crop production while utilizing nutrients efficiently and minimizing negative impacts on water quality. There is a particular concern about nutrient export to the Gulf of Mexico via loss from subsurface drainage systems. The objective of this study was to investigate the effects of crop rotation, tillage, crop residue removal, swine manure applications, and cereal rye (Secale cereale L.) cover crops on nitrate-N (NO3 -N) and total reactive phosphorus (TRP) loss via subsurface drainage. The study was evaluated from 2008 through 2015 using 36 0.4-ha plots outfitted with a subsurface drainage water quality monitoring system. Results showed that when swine manure was applied before both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.], drainage water had significantly higher 8-yr-average flow-weighted NO3 -N concentrations compared with swine manure applied before corn only in a corn-soybean rotation. The lowest NO3 -N loss was 15.2 kg N ha-1  yr-1 from a no-till corn-soybean treatment with rye cover crop and spring application of urea-ammonium nitrate (UAN) to corn. The highest NO3 -N loss was 29.5 kg N ha-1  yr-1 from swine manure applied to both corn and soybean. A rye cover crop reduced NO3 -N loss, whereas tillage and residue management had little impact on NO3 -N loss. Losses of TRP averaged <32 g P ha-1  yr-1 from all treatments. Corn yield was negatively affected by both no-till management and cereal rye cover crops. Results showed that cropping management affected N leaching but impacts on P leaching were minimal.