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Martynova-Van Kley M.A.,Stephen F. Austin State University | Oviedo-Rondon E.O.,North Carolina State University | Dowd S.E.,Research and Testing Laboratories | Hume M.,Food and Feed Safety Research Unit | And 2 more authors.
International Journal of Poultry Science | Year: 2012

Coccidiosis causes mucosal damage and predisposes birds to enteropathogen infection. In this study pyrosequencing was used to evaluate effects of coccidiosis on the intestinal microflora of broilers given diets without feed additives or supplemented with either a growth promotant antibiotic and an ionophore, or two essential oil blends. DNA samples were collected from the cecal contents of broilers before (19 d) and after (26 d) infection with mixed Eimeria spp. (E. acervulina, E. maxima and E. tenella). A 454 FLX pyrosequencer and 16S universal primers were used to obtain quantitative profiles of bacterial taxa present in each sample. The relative percent abundance of the identified taxa was analyzed using hierarchical clustering and principal component analysis. Samples from pre-infected broilers were dominated by bacterial species belonging to genera Subdoligranulum, Coprococcus, Alistipes, Lactobacillus and Faecalibacterium. Post-infection samples were dominated by species from the genera Escherichia/Shigella and Bacteroides. Eimeria infection did not significantly affect the richness of the microbial communities but rather its composition. The composition of the cecal microbiome correlated with the average feed conversion ratio. The methodology used in this study proved effective in understanding the effects of coccidia infection on intestinal microflora of broilers raised on diets supplemented with growth promoting antibiotics, ionophores and essential oils. © Asian Network for Scientific Information, 2012. Source

Jiang W.,China Agricultural University | Beier R.C.,Food and Feed Safety Research Unit | Wang Z.,China Agricultural University | Wu Y.,China National Center for Food Safety Risk Assessment | Shen J.,China Agricultural University
Journal of Agricultural and Food Chemistry | Year: 2013

Immunoassays contribute greatly to food safety. Yet there are no reported immunoassays that simultaneously detect MQCA and QCA, the marker residues for olaquindox and carbadox, respectively. Here, a broad-specificity mAb was successfully produced, and the mAb showed good cross-reactivity with both MQCA and QCA, having IC50 values in buffer of 4.8 and 9.6 ng/mL, respectively. The calibration curves ranged from 0.3 to 81 μg/kg. The average recoveries ranged from 76% to 108% at different spiked levels (2, 4, and 8 μg/kg for MQCA; and 4, 10, and 20 μg/kg for QCA), and the intra-/interday coefficients of variation were 4.2-13.3%. The limits of detection of MQCA and QCA in chicken, fish, pork, and shrimp were 1.76, 1.32, 1.90, and 1.18 μg/kg, respectively. This method was verified by LC-MS/MS, with a correlation coefficient above 0.98. The immunoassay was rapid and reliable for simultaneous screening analysis of MQCA and QCA residues. © 2013 American Chemical Society. Source

Xu Z.-L.,South China Agricultural University | Xu Z.-L.,CAS South China Botanical Garden | Dong J.-X.,South China Agricultural University | Wang H.,South China Agricultural University | And 7 more authors.
Journal of Agricultural and Food Chemistry | Year: 2012

A single-chain variable fragment (scFv) linked alkaline phosphatase (AP) fusion protein for detection of O,O-diethyl organophosphorus pesticides (O,O-diethyl OPs) was produced and characterized. The scFv gene was prepared by cloning VL and VH genes from hybridoma cells secreting monoclonal antibody with broad specificity for O,O-diethyl OPs. The amplified VL and VH regions were assembled using a linker (Gly 4Ser)3 by means of splicing overlap extension polymerase chain reaction to obtain the scFv gene, which was cloned into the expression vector pLIP6/GN containing an AP gene to produce the scFv-AP fusion protein in Escherichia coli strain BL21. The protein was purified by antigen-conjugated immunoaffinity chromatography and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and competitive direct enzyme-linked immunosorbent assay (cdELISA). The fusion protein is bifunctional, retaining both antigen binding specificity and AP enzymatic activity. Analysis of spiked and blind river water and Chinese cabbage samples demonstrated that the fusion protein based cdELISAFP exhibited good sensitivity and reproducibility. © 2012 American Chemical Society. Source

Zhong X.,China Agricultural University | Shi Y.,China Agricultural University | Chen J.,China Agricultural University | Xu J.,China Agricultural University | And 4 more authors.
Biological and Pharmaceutical Bulletin | Year: 2014

Avian pathogenic Escherichia coli (APEC) causes inflammation in multiple organs of chickens called avian colibacillosis, and results in serious economic loss to the chicken industry. Polyphenolic compounds possess a wide range of physiological activities that may contribute to their beneficial effects against inflammation-related diseases. In this study, the curative effect and mechanism of action of the polyphenolic extracts from Punica granatum L. and Terminalia chebula RETZ. in chickens challenged with APEC were studied. Specific-pathogen-free white Leghorn chickens (males, 21-d old) were challenged with APEC and then given oral administration of extracts of P. granatum and T. chebula. The extracts decreased the morbidity and inflammation induced by APEC. Data from quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay showed that the extracts of P. granatum and T. chebula polyphenols (GCP) reversed the over-expression genes of the Toll-like receptor (TLR) 2, 4, and 5, down-regulated the activation of nuclear factor-kappa B signal transduction pathways, and inhibited the production of proinflammatory cytokines. Naturally occurring GCP may be a potential alternative medicine for the prevention or treatment of avian colibacillosis. © 2014 The Pharmaceutical Society of Japan. Source

Edrington T.S.,Food and Feed Safety Research Unit | Bischoff K.M.,Renewable Product Technology Research Unit | Loneragan G.H.,Texas Tech University | Nisbet D.J.,Food and Feed Safety Research Unit
Journal of Animal Science | Year: 2014

Dried distiller's grains (DG) produced from ethanol fermentations dosed with 0 (control), 2, or 20 mg/kg virginiamycin-based product or spiked with virginiamycin (VM) postfermentation were fed to cattle and effects on antimicrobial susceptibility, and prevalence of antimicrobial resistance genes in commensal bacteria was examined. Biological activity assays of DG (from each fermentation) indicated a concentration of 0, 0.7, and 8.9 mg/kg VM, respectively. Twenty-four crossbred beef steers were fed 1 of 4 diets (containing 8% of each of the different batches of DG) and a fourth using 8% of the control DG (0 mg/kg VM) + 0.025 g/kg V-Max50 (positive control) for 7 wk. Fecal samples were collected weekly throughout the experimental period and cultured for Escherichia coli and Enterococcus, and isolates were examined for antimicrobial susceptibility, antimicrobial resistance genes (vatE, ermB, and msrC in Enterococcus), and integrons (E. coli). No treatment differences (P > 0.05) were observed in antimicrobial susceptibility of the E. coli isolates. Enterococcus isolates were resistant to more antimicrobials; however, this was influenced by the species of Enterococcus and not treatment (P > 0.10). The prevalence of ermB was greater (P < 0.05) in the control isolates after 4 and 6 wk while at wk 7, prevalence was greater (P < 0.01) in the 0.7 and 8.9 mg/kg VM treatments. Taken together, the minor treatment differences observed for the presence of ermB coupled with the lack of effect on antimicrobial susceptibility patterns suggest that feeding DG containing VM residues should have minimal if any impact on prevalence of antimicrobial resistance. © 2014 American Society of Animal Science. All rights reserved. Source

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