Gang Qiu

Tibial dyschondroplasia is highly associated with suppression of tibial angiogenesis through regulating the HIF-1α/VEGF/VEGFR signaling pathway in chickens

Tibial dyschondroplasia (TD) is an intractable poultry problem that is characterized by the appearance of non-vascularized and non-mineralized cartilage masses in tibial growth plates (TGPs). However, the role of angiogenesis inhibition in the occurrence of TD remains unknown. In this study, we found that, compared to low-altitude Arbor Acres chickens (AACs), high-altitude Tibetan chickens showed higher tibial vascular distributions that were accompanied by up-regulation of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA) and VEGF receptors. These observations provide insights into hypoxia-induced angiogenesis, which may be related to the absence of TD in high-altitude native Tibetan chickens. Importantly, hypoxia experiments also showed that during hypoxia, tibial angiogenesis was enhanced, which was due to pro-angiogenic factor up-regulation (including VEGFA, VEGFR1, VEGFR2, and IL-8), in AACs. Moreover, we observed that thiram-induced TD could strongly inhibit tibial angiogenesis in the hypertrophic zone through coordinated down-regulation of HIF-1α and pro-angiogenic factors, leading to a disruption in the blood supply to the TGP. Taken together, these findings reveal that the occurrence of TD is highly associated with inhibition of tibial angiogenesis through down-regulated expression of HIF-1α, VEGFA and VEGF receptors, which results in suppression of TGP development.

High altitude hypoxia as a factor that promotes tibial growth plate development in broiler chickens

Tibial dyschondroplasia (TD) is one of the most common problems in the poultry industry and leads to lameness by affecting the proximal growth plate of the tibia. However, due to the unique environmental and geographical conditions of Tibet, no case of TD has been reported in Tibetan chickens (TBCs). The present study was designed to investigate the effect of high altitude hypoxia on blood parameters and tibial growth plate development in chickens using the complete blood count, morphology, and histological examination. The results of this study showed an undesirable impact on the overall performance, body weight, and mortality of Arbor Acres chickens (AACs) exposed to a high altitude hypoxic environment. However, AACs raised under hypoxic conditions showed an elevated number of red blood cells (RBCs) and an increase in hemoglobin and hematocrit values on day 14 compared to the hypobaric normoxia group. Notably, the morphology and histology analyses showed that the size of tibial growth plates in AACs was enlarged and that the blood vessel density was also higher after exposure to the hypoxic environment for 14 days, while no such change was observed in TBCs. Altogether, our results revealed that the hypoxic environment has a potentially new role in increasing the blood vessel density of proximal tibial growth plates to strengthen and enhance the size of the growth plates, which may provide new insights for the therapeutic manipulation of hypoxia in poultry TD.

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.

Epidemiology of Toxoplasma gondii infection in native Tibetans in Tibet, China.

Toxoplasma gondii (T. gondii) is one of the most common and widespread protozoan parasite which caused toxoplasma infection in animals and humans. Toxoplasma infection in healthy people is usually asymptomatic and it can lead to serious pathological effects in congenital cases and immunodeficient patients. The aim of the study is to investigate the prevalence of T. gondii infection in native Tibetans in Tibet as scarce information is available on such a high plateau. A total of 600 blood samples were collected from Tibetans people who visited the hospital in Nyingchi city with the history of flu, swollen lymph glands, muscle pain, and neurological or eyes complications (showing single or more signs). The serum of collected samples were tested for IgG antibody by ELISA. The result showed that the prevalence in men and women were 11.3% and 11.0%, respectively, the prevalence in different ages were 9.8% in <7 years, 6.2% in ≥7–17 years, 10.1% in ≥18–40 years, 14.8% in ≥41–65 years and 11.6% in ≥66 years. The current study indicates the first report of this zoonotic parasite infection in Tibetan people.

Role and regulation of growth plate vascularization during coupling with osteogenesis in tibial dyschondroplasia of chickens

Tibial dyschondroplasia (TD) is the most-prevalent leg disorder in fast-growing chickens; it is intractable and characterized by abnormal endochondral bone formation of proximal tibial growth-plates (TGPs). Previous studies have shown that bone is a highly vascularized tissue dependent on the coordinated coupling between angiogenesis and osteogenesis, but the underlying mechanisms of bone formation and bone remodeling are poorly defined in TD chickens. Here, we observed that inhibition of vasculogenesis and angiogenesis remarkably impaired vascular invasion in the hypertrophic chondrocyte zone of the TGPs, resulting in the massive death of chondrocytes due to a shortage of blood vessels and nutrients. Moreover, the balance of the OPG (osteoprotegerin)/RANKL (receptor activator of nuclear factor-kB ligand) system is also severely disrupted during the osteogenesis process while coupling with angiogenesis, both of which eventually lead to abnormal endochondral bone formation in TD chickens. Thus, the process of vascular formation in endochondral bone appears to initiate the pathological changes in TD, and improvement of this process during coupling with osteogenesis may be a potential therapeutic approach to treat this intractable disease.

Tibial dyschondroplasia is closely related to suppression of expression of hypoxia-inducible factors 1α, 2α, and 3α in chickens

Tibial dyschondroplasia (TD) cases has not been reported in Tibetan chickens (TBCs), but it is commonly seen in commercial broilers characterized by lameness. The underlying mechanism remains unclear. Hypoxia-inducible factors (HIFs) are important regulators of cellular adaptation to hypoxic conditions. In this study, we investigated the role of HIF-1α, -2α, and -3α in hypoxia and thiram-induced TD and their effect on tibial growth plate development in Arbor Acres chickens (AACs) and TBCs. RNA and protein expression levels of HIF-1α, -2α, and -3α were determined by using quantitative reverse transcriptase polymerase chain reaction and western blotting analyses, respectively. Interestingly, the results showed that HIF-1α, -2α, and -3α expressions in the tibial growth plate of TBCs were upregulated by hypoxia and the change was more significant in TBCs than in AACs. However, these factors were downregulated in thiram-induced TD. To further clarify the effect of thiram on tibial growth plate in commercial broilers, AACs were observed to exhibit more pronounced changes in their growth plate that that in TBCs. Taken together, these results demonstrate that HIF-1α, -2α, and -3α may be important in tibial growth plate development and in the prevention of TD. The present study contributes novel insights on a therapeutic target for poultry TD.

Seasonal variation of Ca, P, Fe, Cu, Mn, Zn, and Se contents in Tibetan pigs

The aim of this study was to detect the levels of calcium(Ca), phosphorus(P), iron(Fe), copper(Cu), manganese(Mn), zinc(Zn) and selenium(Se) in the Tibetan pigs (>6-months-old) in Nyingchi Region(Tibet Autonomous region, P.R.China) in 2016, to discover abnormal contents of several macro- and microelements of Tibetan pigs. Liver tissue and whole blood samples were analyzed for Ca, P, Fe, Cu, Mn, Zn, and Se content by flame atomic absorption spectrophotometry and graphite furnace atomic absorption spectrophotometry. The measured values were compared with reported values to discover any mineral imbalances of the Tibetan pigs. Whole blood and hepatic contents of calcium, iron, copper, manganese, zinc and selenium were significantly lower, and the phosphorus content significantly higher, than the reported values in pig bodies. The iron content in Tibetan pig liver in spring was as low as 235.50 ± 65.54 mg/kg, and the phosphorus content as high as 1537.75 ± 194.07mg/kg; significant differences were found compared to other seasons (P < 0.05). The results indicate that mineral deficiency and imbalance was widespread in Tibetan pigs and there were seasonal effects.