Bacillus subtilis is an important part of the gut microbiota and a commonly used probiotic. In the present study, to assess the biological characteristics and probiotic properties of B. subtilis derived from mink, we isolated B. subtilis MG-1 isolate from mink fecal samples, characterized its biological characteristics, optimized the hydrolysis of casein by its crude extract, and comprehensively analyzed its potential as a probiotic in combination with whole-genome sequencing. Biological characteristics indicate that, under low-pH conditions (pH 2), B. subtilis MG-1 can still maintain a survival rate of 64.75%; under the conditions of intestinal fluid, gastric acid, and a temperature of 70 °C, the survival rate was increased by 3, 1.15 and 1.17 times compared with the control group, respectively. This shows that it can tolerate severe environments. The results of hydrolyzed casein in vitro showed that the crude bacterial extract of isolate MG-1 exhibited casein hydrolyzing activity (21.56 U/mL); the enzyme activity increased to 32.04 U/mL under optimized reaction conditions. The complete genome sequencing of B. subtilis MG-1 was performed using the PacBio third-generation sequencing platform. Gene annotation analysis results revealed that B. subtilis MG-1 was enriched in several Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways, and most genes were related to Brite hierarchy pathways (1485–35.31%) and metabolism pathways (1395–33.17%). The egg-NOG annotation revealed that most genes were related to energy production and conversion (185–4.10%), amino acid transport and metabolism (288–6.38%), carbohydrate transport and metabolism (269–5.96%), transcription (294–6.52%), and cell wall/membrane/envelope biogenesis (231–5.12%). Gene Ontology (GO) annotation elucidated that most genes were related to biological processes (8230–45.62%), cellular processes (3582–19.86%), and molecular processes (6228–34.52%). Moreover, the genome of B. subtilis MG-1 was predicted to possess 77 transporter-related genes. This study demonstrates that B. subtilis MG-1 has potential for use as a probiotic, and further studies should be performed to develop it as a probiotic additive in animal feed to promote animal health.

Pentatrichomonas hominis is a zoonotic pathogen linked to gastrointestinal diseases in various animal species and humans. However, its prevalence of in wild rodents remains unexplored. Therefore, investigating the prevalence and molecular characteristics of P. hominis in wild rodents is essential. M. Replace the crossed out sentence above with the following version:This study assessed the prevalence of P. hominis in wild rodents by analyzing 510 fecal samples using nested PCR. Statistical analysis of risk factors was performed with SAS (v9.0) and SPSS software. The infection rates were 18.18% (16/88) in Yunnan, 0.94% (3/319) in Hunan, and 0% (0/103) in Guangxi. Among the species, Rattus rattus sladeni had the highest infection rate at 40% (2/5), followed by R. flavipectus at 23.08% (9/39), while Niviventer lotipes (0%, 0/23) and R. losea (0%, 0/41) showed no infection. Seasonally, the highest prevalence was observed in autumn (18.18%, 16/88) and the lowest in winter (0%, 0/103). Rodents from farmland had significantly higher infection rates than mountain areas (0%, 0/103) and lakeshores (0.32%, 1/312). Although female rodents had a higher infection rate (4.62%, 11/238) compared to males (2.94%, 8/272), the difference was not statistically significant. Phylogenetic analysis revealed that all P. hominis strains identified belonged to the zoonotic CC1 genotype. This study is the first to describe the distribution of P. hominis in wild rodents, paving the way for further epidemiological research on this parasite in wild animals. Such research is crucial for developing strategies to protect human health from zoonotic threats from wild rodents.

Introduction: Blastocystis sp. is a widespread intestinal protist, that threatens the health of humans and animals. However, epidemiological data on Blastocystis sp. in sika deer are still scarce in China and globally. This study aimed to reveal the infection rate, and subtype distribution of Blastocystis sp. in farmed sika deer across China.Methods: A total of 466 fresh fecal samples were collected from farmed sika deer in northern China. A 600 bp fragment of the SSU rRNA was amplified to detect the presence of Blastocystis sp. in samples.Results: The results revealed an overall infection rate of Blastocystis sp. at 65.02% (303/466). The highest infection rate was found in Shandong (98%, 49/50), followed by Heilongjiang (95.51%, 85/89), while the lowest infection rate was found in Jilin (36.31%, 61/168). Additionally, within the seasonal group, the infection rate was significantly higher in autumn (69.04%) than in summer (43.06%). In the age group, although the infection rate in young animals (68.38%) was higher than in adults (63.90%), no statistical difference was observed. Ten subtypes were identified from 303 Blastocystis sp.-positive samples, including ST1, ST5, ST10, ST14, ST21, ST23, ST24, ST26, ST30 and ST42. Among these, ST10 was the dominant subtype with an infection rate of 43.23% (131/303), and ST1 and ST5 were zoonotic subtypes. Notably, this study is the first to report the presence of ST42 in sika deer.Discussion: These findings suggest that sika deer may be a potential source of human Blastocystis sp. infection. In addition, this study reveals the high infection rate of Blastocystis sp. in farmed sika deer and reports for the first time the presence of ST42 subtype, providing valuable data for the epidemiological study of Blastocystis sp. in sika deer.

Introduction: Blastocystis sp. and Enterocytozoon bieneusi are common zoonotic pathogens threatening human and animal health. These parasites are widely distributed in birds, and substantial research on their prevalence has been conducted. However, no studies on Blastocystis sp. and E. bieneusi in raptors exist.Methods: The present study collected 335 fecal samples from raptors in Changdao, China. The prevalence and genotypes of Blastocystis sp. and E. bieneusi were determined through amplification of SSU rRNA and ITS gene. Phylogenetic analysis was performed using MEGA 11 with the neighbor-joining method (Kimura 2-parameter model, 1000 replicate).Results: The overall infection rates of Blastocystis sp. and E. bieneusi in raptors were 1.19% (4/335) and 1.79% (6/335), respecttively. Among them, the highest infection rate of Blastocystis sp. was observed in Accipiter nisus (3.85%, 1/26), while Buteo japonicus showed the highest infection rate of E. bieneusi (33.33%, 1/3), followed by Asio otus (7.69%, 1/13). This study identified two Blastocystis sp. subtypes: ST3 and ST10 in raptors for the first time. Regarding E. bieneusi in raptors, we identified four genotypes: CHN-F1, HND-III, BEB6, and HLJD-I. Among these, BEB6 and CHN-F1 are notable for their zoonotic potential and the risk of waterborne outbreaks.Discussion: These findings suggest that raptors may be potential transmitters of Blastocystis sp. and E. bieneusi to humans and other animals, as well as sources of water contamination. This study fills a gap in the research on Blastocystis sp. and E. bieneusi in raptors and is important for public health safety.