Biology subjects

Zhang, G. F.

Publications and source records attributed to Zhang, G. F..

5 recordsLinked to original sources

bioRxiv2025

Effects of Combined Viral and Bacterial Vaccine on Production Performance in Broiler Chickens

This study formulated a novel inactivated vaccine containing Newcastle disease virus (Lasota strain), avian influenza virus (BZ strains), APG, adenovirus and ORT. The vaccine was administered to 1-day-old and 7-day-old fast-growing broiler chickens. Experimental results showed that the vaccine reduced the feed conversion ratio and induced high levels of antibodies against Newcastle disease (Lasota strain), avian influenza (BZ strains), and avian rhinotracheitis. Immunization at 1 day of age had a significant impact on the production of antibodies against adenovirus. Challenge tests indicated that the vaccine partially protected the broiler chickens against Avibacterium paragallinarum types A, B, and C in broilers. Post-mortem examination of the injection sites showed good absorption with no significant unabsorbed oil droplets or hyperplasia in both 1-day-old and 7-day-old immunized chickens. This study demonstrated that combined viral and bacterial vaccine enhanced the feed conversion ratio in broiler chickens.

microbiology↗

bioRxiv2025

Immunogenicity of different types of adjuvants in bacterial vaccine

This study aims to investigate four common trivalent avian infectious coryza (AIC) vaccines available on the market. It detects the antibody levels of three serotypes at 7 days and 14 days after the first immunization, and at 30 days, 90 days, and 180 days after the second immunization using HI (Hemagglutination Inhibition Test) and ELISA (Enzyme-Linked Immunosorbent Assay). Additionally, the levels of cytokines including IFN-{gamma} (Interferon-Gamma), IL-2 (Interleukin-2), and IL-3 (Interleukin-3) are measured. Furthermore, the protective rates of four of these vaccines are verified 180 days later. It demonstrated that the immunogenicity of mineral oil adjuvanted vaccine is higher than that of Aluminum adjuvanted. The animals should be boosted with another booster immunization six month post the first immunization to protect them from infectious coryza.

microbiology↗

bioRxiv2025

Characteristics of reproductive tract microbiota in health and disease

The symbiotic relationship between the microbiota and the host is crucial to host health. The reproductive tract microbiota in health and disease was examined by next-generation sequencing for the first time in this study. A total of 10 healthy and 30 diseased samples were collected for microbiota analysis. Species distributions, alpha diversity, beta diversity, and functional gene prediction were analyzed. Riemerella anatipestifer, Escherichia coli, Avibacterium paragallinarum, Ornithobacterium rhinotracheale, Enterococcus faecalis, and Acinetobacter baumannii were first identified as pathogenic bacteria at higher abundance in the reproductive tract of the laying hens. The diseased group exhibited dysbacteriosis and a different species-abundance cluster compared with the healthy control. Alpha-diversity analysis showed that the ACE index in the control group was significantly higher than in the diseased group. Beta diversity analysis indicates that samples from the healthy group had a more similar composition than those from the diseased group. Moreover, functional gene prediction analysis indicated that diseased groups showed a high level of gram-negative, facultative anaerobic, and potentially pathogenic bacteria. The pathogenic bacteria identified in this study are helpful for vaccine development and disease treatment. In conclusion, next-generation sequencing is an effective method for analyzing bacterial communities to support health assessment and disease diagnosis.

microbiology↗

bioRxiv2024

16S rRNA gene sequencing for bacterial identification and infectious disease diagnosis

16S rRNA gene sequence is the most common housekeeping genetic marker to study bacterial phylogeny and taxonomy. Therefore, 16S rRNA gene sequencing has the potential to identify novel bacteria and diagnose bacteria. This study compared 16S rRNA gene sequencing with conventional PCR for bacterial identification and disease diagnosis. The bacterial community in healthy and diseased hosts was analyzed by 16S rRNA gene sequencing. 16S rRNA gene sequencing is more sensitive than conventional PCR in detecting bacteria. Moreover, 16S rRNA gene sequencing is adequate to identify novel bacteria. 16S rRNA gene sequencing demonstrated that most pathogenic bacteria persist in diseased or healthy hosts in different abundance. Pathogenic bacteria, such as well-known chicken pathogen Avibacterium paragallinarum, Ornithobacterium rhinotracheale, and Gallibacterium anatis, were identified as indicator species of diseased samples. Alpha diversity analysis showed that the healthy group species is significantly higher than in the diseased groups. Beta diversity analysis also demonstrated differences between healthy and infected groups. The study concluded that 16S rRNA gene sequencing is a more sensitive method for detecting pathogens, and microbiota analysis can distinguish between healthy and diseased samples. Eventually, 16S rRNA gene sequencing has represented the potential in human and animal clinical diagnosis and novel bacterial identification.

microbiology↗

bioRxiv2024

A detailed analysis of 16S rRNA gene sequencing and conventional PCR-based testing for the diagnosis of bacterial pathogens and discovery of novel bacteria

This study represents the first analysis of the bacterial community in chickens affected by swollen head syndrome, utilizing 16S rRNA gene sequencing. Samples were obtained from clinical laying chickens and were examined for the presence of Avibacterium paragallinarum (APG) and Ornithobacterium rhinotracheale (ORT) using conventional polymerase chain reaction (PCR). From the samples, five APG-positive (APG) and APG-negative (N-APG) samples were chosen, along with five specific pathogen-free chickens, for 16S rRNA gene sequencing. Results showed that APG and ORT were widely detected in the chicken samples with swollen head syndrome (SHS, 9/10), while APG was detected in all five specific pathogen-free (SPF) samples. In contrast, conventional PCR sensitivity was found to be inadequate for diagnosis, with only 35.7% (5/14) and 11.1% (1/9) sensitivity for APG and ORT, respectively, based on 16S rRNA gene sequencing data. Furthermore, 16S rRNA gene sequencing was able to quantify the bacteria in the samples, revealing that the relative abundance of APG in the APG group ranged from 2.7% to 81.3%, while the relative abundance of APG in the N-APG group ranged from 0.1% to 21.0%. Notably, a low level of APG was also detected in all 5 SPF samples. The study also identified a significant number of animal and human common bacterial pathogens, including but not limited to Gallibacterium anatis, Riemerella columbina, Enterococcus cecorum, Mycoplasma synoviae, Helicobacter hepaticus, and Staphylococcus lentus. In conclusion, 16S rRNA gene sequencing is a valuable tool for bacterial pathogen diagnosis and the discovery of novel bacterial pathogens, while conventional PCR is not reliable for diagnosis.

microbiology↗