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Journal of Food Protection Oct 2015This study evaluated distillers grain (DG) by-products produced in different ethanol plants and supplemented in animal diets in Texas, based on samples analyzed from...
This study evaluated distillers grain (DG) by-products produced in different ethanol plants and supplemented in animal diets in Texas, based on samples analyzed from 2008 to 2014. The samples were assessed for concentration, occurrence, and prevalence of selected nutrients and contaminants. Protein and sulfur contents of DG were largely different between corn and sorghum by-products as well as wet distillers grain with solubles and dry distillers grain with solubles (DDGS), indicating a significant effect of grain feedstock and dry-grind process stream on DG composition and quality. Salmonella was isolated in 4 DDGS samples out of a total of 157 DG samples, a percentage (2.5%) that is much lower than the percentage of Salmonella-positive samples found in other feed samples analyzed during the same period. A small amount of virginiamycin residue was found in 24 corn DDGS, 1 corn wet distillers grain with solubles, and 2 sorghum DDGS samples out of 242 samples in total. One sorghum DDGS sample out of 168 DG samples was contaminated with bovine spongiform encephalopathy, but the transmission route of the bovine spongiform encephalopathy agent could not be clearly defined. The concentrations of aflatoxin and fumonisin DG by-products averaged 3.4 μg/kg and 0.7 mg/kg, respectively. Among contaminated corn DG samples, five DDGS samples for aflatoxin contained a higher concentration than the U.S. Food and Drug Administration action level for use in animal feed, whereas no sample for fumonisin was found above the action level. The study results raised some important issues associated with the quality and use of DG by-products, suggesting several approaches and strategies for their effective and safe use as a feed ingredient to promote animal and human health and welfare.
PubMed: 26408135
DOI: 10.4315/0362-028X.JFP-15-157 -
Journal of Animal Science Jun 2018The judicious use of commercial products in livestock operations can be part of a sustainable and environmentally friendly production scenario. This study was designed...
The judicious use of commercial products in livestock operations can be part of a sustainable and environmentally friendly production scenario. This study was designed to gather published data of virginiamycin (VM) used in feedlot conditions of the United States and analyze its effectiveness and optimum dosage in reducing the liver abscess incidence (LAI). The dataset contained 26 studies that evaluated more than 7,156 animals of diverse breeds fed in several regions in the United States under different management. Statistical analyses included contingency tables to assess the nonparametric independence of the LAI, meta regression analysis to remove study effects and to evaluate LAI and animal performance, broken-line analysis to determine thresholds of VM dosage on LAI, and residual-based shading mosaic plots to illustrate the contingency analysis. There were 1,391 of 5,430 animals with LAI scores 1, 2, or 3 (LAI1-3) and 651 of 4,690 animals with LAI A+ (score 3). Our analyses suggested that there was a significant dependency (χ2P-value < 0.001) and significant asymmetry (McNemar's test P-value < 0.001) between LAI and VM treatment for both LAI1-3 and LAI A+. For the LAI1-3 group, only 22.5% of the treated animals had liver abscesses compared with 31.7% of the control animals. The metaregression analysis indicated that LAI1-3 was linearly reduced (P < 0.001) by about 0.42% per mg/kg of DM of VM. The lower 95% confidence interval of the intercept for LAI1-3 and LAI A+ obtained with a generalized nonlinear mixed regression was 18.7 and 20.3 mg/kg of DM, respectively. The broken-line regression analysis identified 2 thresholds for LAI (23.9 and 12.3 mg/kg of DM) at which the reduction in total LAI1-3 and LAI A+, respectively, would decrease faster as VM dosage increases (from 2.14% to 6% and from 1.91% to 4.33% per mg of VM per kg of DM, respectively). Additionally, our analyses indicated that after accounting for the study effects, VM significantly increased ADG at 2.08 g BW/d per mg/kg DM compared with 0.92 g BW/d per mg/kg DM for monensin (P < 0.001), suggesting that VM was about 2.3 times more effective in increasing ADG for the same dosage and feeding period length. All analyses yielded consistent results that led us to conclude that VM is effective in reducing LAI when fed between approximately 12 and 24 mg/kg of DM, and the maximum reduction might occur at approximately 24 mg/kg of DM or higher.
Topics: Animal Feed; Animals; Anti-Bacterial Agents; Cattle; Diet; Female; Incidence; Liver Abscess; Male; Monensin; Virginiamycin
PubMed: 29846632
DOI: 10.1093/jas/sky121 -
Antimicrobial Agents and Chemotherapy Dec 2014Combinations of group A and B streptogramins (i.e., dalfopristin and quinupristin) are "last-resort" antibiotics for the treatment of infections caused by Gram-positive...
Combinations of group A and B streptogramins (i.e., dalfopristin and quinupristin) are "last-resort" antibiotics for the treatment of infections caused by Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Resistance to streptogramins has arisen via multiple mechanisms, including the deactivation of the group A component by the large family of virginiamycin O-acetyltransferase (Vat) enzymes. Despite the structural elucidation performed for the VatD acetyltransferase, which provided a general molecular framework for activity, a detailed characterization of the essential catalytic and antibiotic substrate-binding determinants in Vat enzymes is still lacking. We have determined the crystal structure of S. aureus VatA in apo, virginiamycin M1- and acetyl-coenzyme A (CoA)-bound forms and provide an extensive mutagenesis and functional analysis of the structural determinants required for catalysis and streptogramin A recognition. Based on an updated genomic survey across the Vat enzyme family, we identified key conserved residues critical for VatA activity that are not part of the O-acetylation catalytic apparatus. Exploiting such constraints of the Vat active site may lead to the development of streptogramin A compounds that evade inactivation by Vat enzymes while retaining binding to their ribosomal target.
Topics: Acetyl Coenzyme A; Acetyltransferases; Amino Acid Sequence; Anti-Bacterial Agents; Bacterial Proteins; Catalytic Domain; Crystallography, X-Ray; Drug Resistance, Bacterial; Gene Expression; Gram-Negative Bacteria; Gram-Positive Bacteria; Models, Molecular; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Binding; Recombinant Proteins; Sequence Alignment; Streptogramin A
PubMed: 25223995
DOI: 10.1128/AAC.03743-14 -
Journal of Food Protection Sep 2016This article contains the results of the evaluation of distillers grain (DG) coproducts from different ethanol plants around the United States and supplemented in animal...
This article contains the results of the evaluation of distillers grain (DG) coproducts from different ethanol plants around the United States and supplemented in animal diets in Texas, based on samples analyzed from 2008 to 2014. The samples were assessed for concentration, occurrence, and prevalence of selected nutrients and contaminants. Protein and sulfur contents of DG were largely different between maize and sorghum coproducts, as well as wet distillers grain with solubles (WDGS) and dried distillers grain with solubles (DDGS), indicating a significant effect of grain feedstock and dry grind process stream on DG composition and quality. Salmonella was isolated in 4 DDGS samples of a total of 157 DG samples, a percentage (2.5%) that is lower than the percentage of Salmonella -positive samples found in other feed samples analyzed during the same period. A small amount of virginiamycin residue was found in 24 maize DDGS, 1 maize WDGS, and 2 sorghum DDGS samples of 242 samples in total. One sorghum DDGS sample of 168 DG samples was contaminated with animal protein prohibited for use in ruminant feed and was channeled to poultry feed. The concentrations of aflatoxin and fumonisin DG coproducts averaged 3.4 μg/kg and 0.7 mg/kg, respectively. Among contaminated maize DG samples, five DDGS samples for aflatoxin contained a higher concentration than the U.S. Food and Drug Administration (FDA) minimum action level of 20 μg/kg for use in animal feed, whereas no sample for fumonisin was found above the action level of 5 mg/kg. The study provides the most current results involving DG coproducts and associated hazards that will assist development of food safety plans required by the FDA in their September 2015 rule titled "Current Good Manufacturing Practice Hazard Analysis and Risk Based Preventive Controls for Food for Animals."
Topics: Animal Feed; Animals; Diet; Edible Grain; Ethanol; Sorghum; Texas; Zea mays
PubMed: 28221926
DOI: 10.4315/0362-028X.JFP-16-072 -
Proceedings of the National Academy of... Sep 2018Many Gram-positive pathogenic bacteria employ ribosomal protection proteins (RPPs) to confer resistance to clinically important antibiotics. In , the RPP VmlR confers...
Many Gram-positive pathogenic bacteria employ ribosomal protection proteins (RPPs) to confer resistance to clinically important antibiotics. In , the RPP VmlR confers resistance to lincomycin (Lnc) and the streptogramin A (S) antibiotic virginiamycin M (VgM). VmlR is an ATP-binding cassette (ABC) protein of the F type, which, like other antibiotic resistance (ARE) ABCF proteins, is thought to bind to antibiotic-stalled ribosomes and promote dissociation of the drug from its binding site. To investigate the molecular mechanism by which VmlR confers antibiotic resistance, we have determined a cryo-electron microscopy (cryo-EM) structure of an ATPase-deficient VmlR-EQ mutant in complex with a ErmDL-stalled ribosomal complex (SRC). The structure reveals that VmlR binds within the E site of the ribosome, with the antibiotic resistance domain (ARD) reaching into the peptidyltransferase center (PTC) of the ribosome and a C-terminal extension (CTE) making contact with the small subunit (SSU). To access the PTC, VmlR induces a conformational change in the P-site tRNA, shifting the acceptor arm out of the PTC and relocating the CCA end of the P-site tRNA toward the A site. Together with microbiological analyses, our study indicates that VmlR allosterically dissociates the drug from its ribosomal binding site and exhibits specificity to dislodge VgM, Lnc, and the pleuromutilin tiamulin (Tia), but not chloramphenicol (Cam), linezolid (Lnz), nor the macrolide erythromycin (Ery).
Topics: ATP-Binding Cassette Transporters; Allosteric Regulation; Anti-Bacterial Agents; Bacillus subtilis; Bacterial Proteins; Drug Resistance, Bacterial; RNA, Transfer; Ribosomes
PubMed: 30126986
DOI: 10.1073/pnas.1808535115 -
International Journal of Antimicrobial... Nov 2019A lincosamide-resistant and macrolide-susceptible phenotype has not been described to date in Streptococcus pyogenes [group A streptococcus (GAS)]. The aim of this study...
A novel genomic island harbouring lsa(E) and lnu(B) genes and a defective prophage in a Streptococcus pyogenes isolate resistant to lincosamide, streptogramin A and pleuromutilin antibiotics.
A lincosamide-resistant and macrolide-susceptible phenotype has not been described to date in Streptococcus pyogenes [group A streptococcus (GAS)]. The aim of this study was to characterize a GAS isolate susceptible to macrolides but resistant to lincosamide, streptogramin A and pleuromutilin antibiotics. Antimicrobial susceptibility was tested using the microdilution broth method and the resistance phenotype was tested by D-test. The GAS2887HUB isolate was subjected to whole-genome sequencing. The isolate showed a positive Gots' test (clindamycin inactivation). Whole-genome sequencing revealed that the strain was ST10 and emm93, and had five resistance genes [lnu(B), ant(6)-Ia, aph(3')-III, tet(M) and dfrG]. The tet(M) gene was located in a Tn916-like transposon. The lsa(E)-lnu(B)-containing sequence (inserted downstream of the rumA gene) was formed by a 39.6-kb prophage, followed by a gene cluster encoding aminoglycoside-streptothricin resistance [ant(6)Ia-sat4-aph(3')III] and lsa(E)-lnu(B) genes. This structure was not transferred by conjugation. This study identified a new genetic element carrying a determinant of lincosamide resistance in a GAS. Further molecular epidemiological surveys are needed to determine the prevalence of this mechanism of resistance in GAS.
Topics: Anti-Bacterial Agents; DNA, Bacterial; Defective Viruses; Diterpenes; Drug Resistance, Multiple, Bacterial; Genome, Bacterial; Genomic Islands; Humans; Lincosamides; Microbial Sensitivity Tests; Polycyclic Compounds; Prophages; Streptococcus pyogenes; Streptogramin A; Whole Genome Sequencing; Pleuromutilins
PubMed: 31476434
DOI: 10.1016/j.ijantimicag.2019.08.019 -
Animals : An Open Access Journal From... Mar 2021There are concerns about inclusion of antibiotics in the feed of broiler chickens, because of the development of antibiotic resistance, leading to a search for...
There are concerns about inclusion of antibiotics in the feed of broiler chickens, because of the development of antibiotic resistance, leading to a search for alternative feed additives. Turnip extract is known to have antibacterial properties but has not been tested in the diet of broiler chickens. We allocated 200 broiler chicks to receive one of four levels of turnip extract in their water, 0, 150, 300 or 450 ppm, or a standard antibiotic, Virginiamycin, over a 42-day growing period. Although initially there were detrimental effects of providing 450 ppm, overall the 150 ppm level of supplementation increased weight gain, compared with birds given Virginiamycin, and decreased gizzard weight. Birds given 150 ppm or Virginiamycin had increased low-density lipoproteins (LDLs) and reduced very low-density lipoproteins (VLDLs) in their blood serum and reduced antibody responses to sheep red blood cells, compared to birds in the 450 ppm treatment. Birds given turnip extract at 450 ppm had fewer Gram-negative lactose and coliform bacteria than those provided with no turnip extract, and those provided with 150-300 ppm had the same as those provided with Virginiamycin. Turnip extract could potentially replace antibiotics included in the feed of broiler chickens for growth promotion and the control of bacterial infection of the gastrointestinal tract.
PubMed: 33803631
DOI: 10.3390/ani11030867 -
Microorganisms Aug 2019Necrotic enteritis, caused by is an enteric disease that leads to poor performance and increased mortality, resulting in significant economic losses in poultry...
Necrotic enteritis, caused by is an enteric disease that leads to poor performance and increased mortality, resulting in significant economic losses in poultry production. This study evaluated the effects of a proprietary prebiotic, probiotic, and plant extract blend on performance of broilers during coccidiosis challenge leading to necrotic enteritis (NE). In total, 744 Cobb500 male broilers were randomly allocated to 3 treatments (8 replicates, 31 birds/pen) including, the negative control (NC) fed a basal diet; the positive control (PC) fed a basal diet with Virginiamycin; and the additive group fed basal diet with a blend of prebiotic, probiotic, and plant extract (BSN). A unique, naturally occurring NE model developed to mimic field conditions was implemented to challenge the birds. This model consists of spraying a concentrated commercial coccidiosis vaccine on litter and feed upon bird placement, which, in conjunction with the presence of . spores in the environment, leads to the development of a NE outbreak one week post vaccine application. At the onset of NE on d7, three birds/pen were selected for scoring NE lesions. Body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were recorded on days 7, 14, 28, and 42. Carcass composition was assessed by dual energy X-ray absorptiometry (DXA) analysis on day 42. Dietary supplementation of BSN significantly ( < 0.05) improved FCR during starter and grower periods. Dietary treatments had no effect on NE lesions in the small intestine. DXA analysis revealed slightly higher lean content in BSN birds compared to NC. These results showed that dietary supplementation of the BSN blend significantly improved broilers performance during the early NE challenge phase, as well as in the grower period.
PubMed: 31412542
DOI: 10.3390/microorganisms7080257 -
BMC Microbiology Oct 2016Quinupristin/dalfopristin (Q/D) is a valuable alternative antibiotic to vancomycin for the treatment of multi-drug resistant Enterococcus faecium infections. However,...
BACKGROUND
Quinupristin/dalfopristin (Q/D) is a valuable alternative antibiotic to vancomycin for the treatment of multi-drug resistant Enterococcus faecium infections. However, resistance to Q/D in E. faecium clinical isolates and nosocomial dissemination of Q/D-resistant E. faecium have been reported in several countries and should be of concern.
RESULTS
From January 2012 to December 2015, 911 E. faecium clinical isolates were isolated from various specimens of inpatients at the first Affiliated Hospital of Wenzhou Medical University located in Wenzhou, east China. Of 911 E. faecium clinical isolates, 9 (1.0 %, 9/911) were resistant to Q/D, with the Q/D MIC values of 64 mg/L(1), 32 mg/L(1), 16 mg/L(3), 8 mg/L(1) and 4 mg/L(3) determined by broth microdilution. All Q/D-resistant isolates were susceptible to vancomycin, tigecycline and teicoplanin but resistant to penicillin, ampicillin and erythromycin. vatE was only found in one Q/D-resistant E. faecium isolate while vatD was not detected in any of the isolates tested. 8 of 9 Q/D-resistant E. faecium isolates were found be positive for both ermB and msrC. The combinations of Q/D resistance determinants were ermB-msrC (7 isolates) and ermB-msrC-vatE (one isolate). ST78, ST761, ST94, ST21 and ST323 accounted for 4, 2, 1, 1 and 1 isolate, respectively, among which ST78 was the prevalent ST.
CONCLUSION
Q/D-resistant E. faecium clinical isolates were first described in China. Carriage of vatE, ermB and msrC was responsible for Q/D resistance.
Topics: Anti-Bacterial Agents; Bacterial Proteins; China; Cross Infection; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Enterococcus faecium; Genes, Bacterial; Gram-Positive Bacterial Infections; Humans; Microbial Sensitivity Tests; Multilocus Sequence Typing; Prevalence; RNA, Ribosomal, 16S; Vancomycin; Virginiamycin
PubMed: 27769188
DOI: 10.1186/s12866-016-0863-8 -
Animals : An Open Access Journal From... Oct 2020Medium-chain fatty acid glycerides have been shown to provide energy for rapid oxidation in the body. The study was conducted to investigate the effects of dietary...
Medium-chain fatty acid glycerides have been shown to provide energy for rapid oxidation in the body. The study was conducted to investigate the effects of dietary supplementation with medium-chain fatty acid glyceride on the growth performance and intestinal health of weaned piglets fed with a low-protein diet. Nighty healthy weaned piglets were randomly divided into five treatments: NP (Normal protein treatment, normal-protein diet no antibiotics included); NC (Negative control, low-protein diet no antibiotics included); PC (Positive control, low-protein diet +75 mg/kg quinocetone, 20 mg/kg virginiamycin and 50 mg/kg aureomycin); MCT (tricaprylin + tricaprin treatment, low-protein diet + tricaprylin + tricaprin); GML (glycerol monolaurate treatment, low-protein diet + glycerol monolaurate). The results showed that the average daily feed intake (ADFI) of the MCT treatment was significantly higher than that of the NP, NC treatments ( < 0.05). In the jejunum, the villus height of the GML treatment was significantly lower than that of the PC treatment ( < 0.05), and the number of goblet cells in the GML treatment was higher than that in the NC treatment ( < 0.05). Compared with the NC treatment, the MCT treatment significantly increased the level of claudin-1, Zonula occludens-1(ZO-1), while the GML treatment significantly increased the level of claudin-1, occludin, ZO-1 ( < 0.05). In the ileum, the level of ZO-1 in the GML treatment was significantly higher than that in the NP, NC, PC treatments ( < 0.05). Compared with the NC treatment, the GML treatment significantly increased the level of Secretory immunoglobulin A (SIgA) in the ileum and serum, while the MCT treatment significantly increased the level of SIgA and decreased the level of interleukin-6 (IL-6) in the ileum ( < 0.05). These results showed that the addition of medium-chain fatty acid glycerides to a low-protein diet could improve the growth performance and intestinal functional barrier of weaned piglets and also improve the immune function of weaned piglets.
PubMed: 33053685
DOI: 10.3390/ani10101852