Zhaoqing Han

Seroprevalence of Toxoplasma gondii infection in yaks (Bos grunniens) on the Qinghai-Tibetan Plateau of China

Toxoplasma gondii (T. gondii), a zoonotic parasite infects almost all warm-blooded animals and causes significant economic losses. To date, however, it is still unclear whether yaks from the Qinghai-Tibetan plateau of China are exposed to T. gondii. On the present study, a survey was conducted for the first time, to investigate the seroprevalence of T. gondii infection in yaks (Bos grunniens) on the Qinghai-Tibetan Plateau (Qinghai, Tibet, Hongyuan area of Sichuan province). A total of 905 and 736 serum samples were collected from yaks in these areas in 2012 and 2013, respectively and assayed for T. gondii antibodies by an indirect hemagglutination test (IHA). The results showed that seroprevalence on plateau was 21.7% and 29.1% in 2012 and 2013, respectively with the prevalence of 22.4%, 19.4% and 25.5% in 2012 for Qinghai, Tibet and Hongyuan of Sichuan, respectively and of 26.4%, 27.0% and 33.7% for these three regions in 2013, respectively. The present survey indicated that the infection with T. gondii in yaks was widely spread in recent years on the plateau causing a high risk factor for animals and humans.

Hsp90 inhibitor celastrol reinstates growth plate angiogenesis in thiram-induced tibial dyschondroplasia

ABSTRACT Tibial dyschondroplasia (TD) is an important long bone defect of broiler chickens that disturbs the proximal growth plate and is characterized by non-vascularized cartilage, a distended growth plate and lameness. Celastrol, a medicinal root extract from the plant Tripterygium wilfordii, is reported widely as a well-known heat-shock protein 90 (Hsp90) inhibitor. Recently, Hsp90 inhibition in chondrocyte differentiation and growth-plate vascularization were effective in restoring the morphology of the growth plate. The present study was aimed at investigating Hsp90 inhibition in TD using celastrol. The broiler chicks were divided into three groups; Control; TD induced (40 mg/kg thiram) and celastrol treatment. Hsp90, vascular endothelial growth factor and Flk-1 expressions were evaluated by quantitative real-time polymerase chain reaction and the protein levels of Hsp90 were measured by Western blot analysis. Antioxidant enzymes were determined to assess the liver damage caused by thiram and the protective effects of the medicine were evaluated by levels of serum biomarkers. The expression levels of Hsp90 and vascular endothelial growth factor mRNA transcripts were increased while Flk-1 receptor was decreased in TD-affected chicks. Celastrol therapy inhibited Hsp90 mRNA and protein levels and up-regulated the expressions of receptor Flk-1 in TD-affected tibial growth plates significantly (P < 0.05) in addition to rectifying the damaging effects of thiram on the liver by decreasing the levels of aspartate aminotransferase, alanine aminotransferase and malondialdehyde and correcting the oxidative imbalance. In conclusion, administering celastrol to dyschondroplastic chicks prevented un-vascularized growth plate, lameness and reinstated angiogenesis. Celastrol may be efficacious for the treatment of TD through the inhibition of Hsp90 expression and limiting the liver damage caused by thiram in broiler chickens.

Zinc Supplementation Protects against Cadmium Accumulation and Cytotoxicity in Madin-Darby Bovine Kidney Cells

Cadmium ions (Cd2+) have been reported to accumulate in bovine tissues, although Cd2+ cytotoxicity has not been investigated thoroughly in this species. Zinc ions (Zn2+) have been shown to antagonize the toxic effects of heavy metals such as Cd2+ in some systems. The present study investigated Cd2+ cytotoxicity in Madin-Darby bovine kidney (MDBK) epithelial cells, and explored whether this was modified by Zn2+. Exposure to Cd2+ led to a dose- and time-dependent increase in apoptotic cell death, with increased intracellular levels of reactive oxygen species and mitochondrial damage. Zn2+ supplementation alleviated Cd2+-induced cytotoxicity and this protective effect was more obvious when cells were exposed to a lower concentration of Cd2+ (10 μM), as compared to 50 μM Cd2+. This indicated that high levels of Cd2+ accumulation might induce irreversible damage in bovine kidney cells. Metallothioneins (MTs) are metal-binding proteins that play an essential role in heavy metal ion detoxification. We found that co-exposure to Zn2+ and Cd2+ synergistically enhanced RNA and protein expression of MT-1, MT-2, and the metal-regulatory transcription factor 1 in MDBK cells. Notably, addition of Zn2+ reduced the amounts of cytosolic Cd2+ detected following MDBK exposure to 10 μM Cd2+. These findings revealed a protective role of Zn2+ in counteracting Cd2+ uptake and toxicity in MDBK cells, indicating that this approach may provide a means to protect livestock from excessive Cd2+ accumulation.

First report of Metastrongylus pudendotectus by the genetic characterization of mitochondria genome of cox1 in pigs from Tibet, China

Lungworms, a world wild distributed parasites cause serious respiratory diseases to the pigs. A high infection rate of Metastrongylus lungworms has been found in Tibetan pigs being slaughtered in different slaughter houses of Tibet autonomous region. The main aim of our study was to detect and confirm the lungworm parasite by the genetic characterization of mitochondrial cox1genome isolated from the lungs of Tibetan pig. The adult lungworms were collected from the lungs of slaughtered pigs and identification was done through morphological examinations. Total genomic DNA of the extracted worms was performed and a fragment (∼450bp) of the cox1 of mitochondrial (mt) gene was amplified. Amplicons were cloned into PGEM(®)-T Easy vector and the positive clones were sequenced from a commercial company. Sequence and phylogenetic analysis were performed by software of DNAMAN and MEGA respectively. The results revealed that the lungworms infecting the Tibetan pigs were Metastrongylus pudendotectus (M. pudendotectus). To our knowledge, this is the first report for the isolation and identification for the genetic characterization of mitochondria (mt) genome of cox1 of M. pudendotectus derived from Tibetan pigs in Tibet, China.

Assessment of Serum Trace Elements in Diarrheic Yaks ( Bos grunniens ) in Hongyuan, China

Diarrhea is one of the main causes of animal deaths especially in neonatal calves. The objective of this study was to investigate the blood serum for cobalt (Co), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), Molybdenum (Mo), selenium (Se), and zinc (Zn) concentrations in yak serum samples by inductively coupled plasma mass spectrometry (ICP-MS) from 35 yaks consisting of 10 healthy and 25 diarrheic ones. Our observations indicated that the concentrations of Mn, Zn, and Fe in yak affected with diarrhea had statistically significant reduced levels as compared to the control group (P < 0.05). The mean concentration of Cu in blood serum of diarrheic yaks was found significantly higher than the normal ones (P < 0.05). The Mn and Zn in the serum of diarrheic groups were observed significantly different (P < 0.05) with different ages. These findings can provide for some valuable information for the investigation on relationship between trace elements in the serum of normal and diarrheic yaks.

Anthelmintic efficacy, plasma and milk kinetics of eprinomectin following topical and subcutaneous administration to yaks (Bos grumniens).

Eprinomectin is recommended for use as an anti-parasitic agent in livestock, including cattle. Yaks are a member of the cattle family living in the high altitude mountains of China and adjacent countries; however, there have been no clinical trials of the anthelmintic efficacy and pharmacokinetics of eprinomectin in yaks. The purpose of this study was to investigate the endectocidal efficacy and pharmacokinetics of eprinomectin following topical (at 0.5 mg/kg) and subcutaneous (at 0.2 mg/kg) administration in the yak. After topical administration, plasma eprinomectin reached a peak value of 15.31 ± 3.71 ng/ml (Cmax) at 3.01 ± 1.22 days (Tmax). In milk, the Cmax was 3.74 ± 1.05 ng/ml at 3.00 ± 0.88 days. The AUC0-t for plasma was 193.84 ± 26.34 ng d/ml and for milk AUC(0-t) was 46.24 ± 10.37 ng d/ml. The mean residence time (MRT) was 10.74 ± 1.44 days and 10.90 ± 3.87 days in plasma and milk, respectively. After subcutaneous administration, the Cmax was 35.78 ± 10.53 ng/ml at 0.91 ± 0.39 days in plasma and 9.10 ± 3.61 ng/ml at 1.61 ± 1.05 days in milk. The MRTs in plasma and milk were 3.07 ± 1.50 and 3.64 ± 1.15 days, respectively. The AUC(0-t) was 133.71 ± 32.51 ng d/ml for plasma and 43.85 ± 14.16 ng d/ml for milk. Both the pour-on and injectable formulation of eprinomectin were similarly efficacious (minimum egg count reductions of 94% and 96.4%, respectively) at each post-treatment time point. However, Tmax, MRT and t(1/2el) were longer, and Cmax of eprinomectin in the plasma and milk were lower, following topical administration compared to those after subcutaneous administration. In conclusion, these results support the use of eprinomectin in yaks. The pour-on formulation of eprinomectin can be recommended for nematode control in lactating yaks with no milk-withdrawal period because of its low residue profile and good efficacy.

Prevalence of Circulating Antibodies to Bovine Herpesvirus 1 in Yaks (Bos grunniens) on the Qinghai-Tibetan Plateau, China.

Abstract Bovine Herpesvirus 1 (BoHV-1) causes infections with many clinical signs, including rhinotracheitis, encephalitis, and genital lesions. The virus occurs worldwide in bovines, and in recent years, it has been reported in yaks (Bos grunniens) inhabiting the Tibetan Plateau in China. However, there is little epidemiologic data describing BoHV-1 infections in China’s yak herds. We conducted a cross-sectional study on the Qinghai–Tibetan Plateau (QTP) in China July 2011–July 2012 to estimate the prevalence of BoHV-1 antibody in yak herds. We collected 1,840 serum samples from yaks on the QTP, in Tibet (988 yaks), Qinghai (475 yaks), and Sichuan (377 yaks) Provinces. Using an enzyme-linked immunosorbent assay, we found that 381 (38.6%) of the Tibetan samples, 212 (44.6%) of the Qinghai samples, and 105 (27.9%) of the Sichuan samples had detectable antibodies to BoHV-1. Given that this high prevalence of infection in yaks could result in heavy economic losses, we suggest that an effective management program, including vaccination and strategies for infection control, be developed.