Recombinant nanobody expressed by transgenic chimeric chickens eliminated vertical transmission of avian leukosis virus subgroup J.

Because of the vertical transmission of avian leukosis virus subgroup J (ALV-J), control of ALV-J in breed of chicken is still a serious issue. Blocking vertical transmission using antibodies is a potential strategy, but its high cost limits its application. We artificially designed recombinant nanobody (Nb) and efficiently expressed and secreted them in three primary chicken cells cultured in vitro by adenovirus delivery.

The Influence of Increasing Roughage Content in the Diet on the Growth Performance and Intestinal Flora of Jinwu and Duroc × Landrace × Yorkshire Pigs.

The Jinwu pig (JW) is a hybrid breed originating from the Chinese indigenous Jinhua pig and Duroc pig, boasting excellent meat quality and fast growth rates. This study aimed to verify the tolerance of JW to roughage, similar to most Chinese indigenous pigs. In this research, two types of feed were provided to JW and Duroc × Landrace × Yorkshire pigs (DLY): a basal diet and a roughage diet (increasing the rice bran and wheat bran content in the basal diet from 23% to 40%) for a 65-day experimental period.

The effect of fixed-time artificial insemination protocol initiated at different stages of the estrous cycle on follicle development and ovulation in gilts.

Hormonal products have been developed for fixed-time artificial insemination (FTAI) to improve the efficiency of swine production. Here, we evaluated the effect of an FTAI protocol initiated during different phases of the estrous cycle on follicle development and ovulation in gilts. A total of 36 gilts were equally divided into three groups designated as the luteal (L), follicular (F), and post-ovulation (O) groups and fed with 20 mg of altrenogest for 18 days, followed by intramuscular injection of 1000 IU PMSG at 42 h after withdrawal of altrenogest, and 100 μg of GnRH after an 80-h interval.

Improving ovulation in gilts using anti-inhibin serum treatment combined with fixed-time artificial insemination.

For successful batch farrowing, porcine oestrus and ovulation must be synchronized using fixed-time artificial insemination (FTAI). However, exogenous gonadotropins, which are currently used in FTAI, negatively affect gilt ovulation. Here, we aimed to improve sexually mature gilt superovulation efficiency using passive immunization against inhibin during FTAI.

Isolation, characterization and germline chimera preparation of primordial germ cells from the Chinese Meiling chicken.

Primordial germ cells (PGCs) are precursors of germline cells that can generate sperm and eggs in adults, making them promising tools for transgenic animal preparation and germplasm preservation, especially in avians. In this study, we purified the PGCs from circulating embryonic blood of Chinese Meiling chickens using Nycodenz density centrifugation, and characterized them by alkaline phosphatase (AKP) staining, periodic acid-Schiff (PAS) staining and stage-specific embryonic antigen-1 (SSEA-1) immunostaining and PGC-specific gene amplification. The purified PGCs were also labeled with PKH26 and transferred into donor chicken embryos at the Hamburger-Hamilton (HH) stage 14 to 16, and cells with red fluorescence were observed in the gonads of 8-d-old embryos.

Effect of shRNA-mediated Xist knockdown on the quality of porcine parthenogenetic embryos.

Background: Parthenogenetically activated oocytes exhibit poor embryo development and lower total numbers of cells per blastocyst accompanied by abnormally increased expression of Xist, a long noncoding RNA that plays an important role in triggering X chromosome inactivation during embryogenesis.

Results: To investigate whether knockdown of Xist influences parthenogenetic development in pigs. We developed an anti-Xist short hairpin RNA (shRNA) vector, which can significantly inhibit Xist expression for at least seven days when injected at 12-13 hr after parthenogenetic activation.

Production of germline transgenic pigs co-expressing double fluorescent proteins by lentiviral vector.

Genomic integration of transgene by lentiviral vector has been proved an efficient method to produce single-transgenic animals. But it failed to create multi-gene transgenic offspring. Here, we have exploited lentivirus to generate the double-transgenic piglets through the female germline.

Construction of a lentiviral T/A vector for direct analysis of PCR-amplified promoters.

The promoter plays an important role in the regulation of gene expression. To analyze a promoter's activity, we developed a novel lentiviral T/A vector that contains two reporter genes, a luciferase (Luc2) gene and a green fluorescent protein (Venus) gene, that are linked via an internal ribosome entry site (IRES2). To test the performance of this vector, phosphoglycerate kinase-1 (PGK) and elongation factor-1α (EF1α) promoters were amplified by PCR and inserted into this lentiviral T/A vector using T4 DNA ligase, yielding two promoter-reporter vectors: pLent-T-PGK and pLent-T-EF1α.

A Colpoda aspera isolate from animal faeces: In vitro cultivation and identification.

A colpodean ciliate was found in the faeces of experimental rabbits. It was initially cultivated in medium mixed with 2% (w/v) rabbit faeces. Subsequently, two chemically defined media, designated CA-1 and CA-2, were found to be suitable for axenical cultivation of the ciliate.

Transgenic quail production by microinjection of lentiviral vector into the early embryo blood vessels.

Several strategies have been used to generate transgenic birds. The most successful method so far has been the injection of lentiviral vectors into the subgerminal cavity of a newly laid egg. We report here a new, easy and effective way to produce transgenic quails through direct injection of a lentiviral vector, containing an enhanced-green fluorescent protein (eGFP) transgene, into the blood vessels of quail embryos at Hamburger-Hamilton stage 13-15 (HH13-15).

Histopathological and gene expression analysis of mice exposed to diethylstilbestrol.

The estrogenic compound diethylstilbestrol (DES) has been widely studied to understand its potential involvement in endocrine function and carcinogenesis. This study examined the influence of DES on adult mice by histopathological analysis and studied the gene expression changes using mRNA differential display. Pathological changes in the mice following DES exposure included testicular atrophy, ovarian and hepatic fibrosis, and reduced numbers of mature oocytes and spermatogenic cells.

Fusion expression of cecropin B-like antibacterial peptide in Escherichia coli and preparation of its antiserum.

Antibacterial peptides have a broad range of antibacterial properties that makes them highly toxic for expression in Escherichia coli. For prepare an antiserum to detect these peptides, we developed a cecropin B mutant with a green fluorescent protein fusion partner resulting in high expression of a 37 kDa fusion peptide in E. coli with a yield of 7.