The microRNA (miRNA) mdv1-miR-M4, a functional miR-155 ortholog encoded by oncogenic Marek's disease virus (MDV), has previously been suggested to be involved in MDV pathogenesis. Using the technique of bacterial artificial chromosome mutagenesis, we have presently evaluated the potential role of mdv1-miR-M4 in the oncogenesis of the very virulent (vv) MDV strain GX0101. Unexpectedly, deletions of the Meq-cluster or mdv1-miR-M4 alone from the viral genome strongly decreased rather than abolished its oncogenicity. Compared to GX0101, mortalities of mutants GXΔmiR-M4 and GXΔMeq-miRs were reduced from 100% to 18% and 4%, coupled with the gross tumor incidence reduction from 28% to 22% and 8%, respectively. Our data suggests that the mdv1-miR-M4 is possibly an important regulator in the development of Marek's disease (MD) lymphomas but is not essential for the oncogenicity of vvMDV. In addition, some of the other Meq-clustered miRNAs may also play potentially critical roles in vvMDV induction of lymphomas.

BackgroundThere is no information concerning the genotype of Canine parvovirus (CPV) currently circulating in Henan province, China. Therefore, the aim of the present study was to provide insights into the epidemiology and molecular characterization of CPV circulating in Henan province from 2009 to 2014.ResultsNineteen thousand nine hundred seven dogs from pet hospitals in the cities of Luoyang, Anyang, Jiaozuo, Sanmenxia, Xinxiang, Zhengzhou in Henan province between 2009 and 2014 were investigated. Over the 6-year period, 1169 CPV-positive cases were identified and the morbidity of CPV infection ranged from 4.16 to 8.06 %, although morbidity was not significant (P > 0.05) between 2009 and 2014. Factors associated with morbidity included sampling season, dog age, breed, vaccination status, and sex. CPV co-infection with coccidium (10.00 %), canine distemper virus (4.79 %), hookworm (2.40 %), canine coronavirus (1.11 %), roundworm (1.03 %), tapeworm (0.17 %) and Babesia spp. (0.09 %) were observed. The new CPV-2a variant was more prevalent than the new CPV-2b variant in Henan province. CPV 2c was not observed in this study.ConclusionsThe epidemiology of CPV infection and identification of the circulating genotypes in Henan province, China from 2009 to 2014 determined that the new CPV-2a variant was more prevalent.

This study aimed to investigate the effect of lactic acid bacteria (LAB) and smectite on the growth performance, nutrient digestibility and blood parameters of broilers that were fed diets contaminated with aflatoxin B (AFB ). A total of 480 newly hatched male Arbor Acres broilers were randomly allocated into four groups with six replicates of 20 chicks each. The broilers were fed diets with the AFB (40 μg/kg) challenge or without (control) it and supplemented with smectite (3.0 g/kg) or LAB (4.0 × 10 CFU/kg) based on the AFB diet. The trial lasted for 42 days. The results showed that during days 1-42 of AFB challenge, the feed intake (FI) and body weight gain (BWG) were depressed (p < .05). The inclusion of LAB and smectite increased (p < .05) the BWG by 71.58 and 41.89 g/bird, respectively, which reached the level of the control diet (p ≥ .05), but there were no differences (p ≥ .05) in performance between LAB and smectite. LAB and smectite also increased (p < .05) the apparent total tract digestibility of the crude protein. Regarding the blood parameters, AFB decreased (p < .05) the levels of red blood cell count, haematocrit, mean corpuscular volume, haemoglobin, albumin and total protein. In the meantime, the AFB increased (p < .05) leucocyte counts, urea nitrogen, cholesterol, total bilirubin, creatinine, glutamic-pyruvic transaminase, glutamic oxaloacetic transaminase and alkaline phosphatase. By contrast, LAB and smectite affected (p < .05) these parameters in the opposite direction. It can be concluded that after the AFB challenge, LAB and smectite have similar effects on the growth and health of the broilers, suggesting that LAB could be an alternative against AFB in commercial animal feeds.

The present study aimed to investigate the effect of tetramethylpyrazine (TMP) supplementation on growth performance, Campylobacter jejuni (C. jejuni) carriage and antimicrobial peptides in the epithelial tissue of caecum and skin in rabbits. Five treatments included control and C. jejuni challenge with the addition of TMP at 0, 50, 100 or 150 mg/kg of diet. The trial lasted for 35 days and C. jejuni challenge occurred on first day of feeding trial. The results showed that C. jejuni challenge worsened (P &lt; 0.05) feed intake, body weight gain and feed efficiency, whereas TMP supplementation partially compensated (P &lt; 0.05) growth performance. C. jejuni populations in the caecal content and on the skin were decreased (P &lt; 0.05) in the treatments containing TMP. The mRNA levels of antimicrobial peptides, including defensin neutrophil peptide 4, macrophage cationic peptide 2, galectin 3 and cathelicidin were also decreased (P &lt; 0.05) by C. jejuni challenge while they were increased (P &lt; 0.05) with supplemental TMP. Linear and quadratic trends (P ≤ 0.012) of the three doses of TMP were found in growth performance, linear trends (P ≤ 0.049) in C. jejuni carriage, and linear and quadratic trends (P ≤ 0.012) in galectin 3. The results suggest that TMP can partially protect from C. jejuni infection by decreasing C. jejuni carriage and activating epithelial antimicrobial peptides.

Marek's disease is a highly contagious, oncogenic, and immunosuppressive avian viral disease. Surveillance of newly registered Marek's disease virus (MDV) isolates is meaningful for revealing the potential factors involved in increased virulence. Presently, we have focused on the molecular characteristics of all available MDVs from China, including 17 new Henan isolates. Based on Meq, gE, and gI genes, we found that most Chinese isolates contain conserved amino acid point mutations in Meq, such as E(77), A(115), A(139), R(176), and A(217), compared to USA virulent MDVs. However, the 59-aa or 60-aa insertions are only found in a few mild MDVs rather than virulent MDVs in China. Further phylogenetic analysis has demonstrated that a different genotype of MDV has been prevalent in China, and for virulent MDVs, their recent evolution has possibly been geographically restricted. Our study has provided more detailed information regarding the field MDVs circulating in China.

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