Effects of Plant Polysaccharides Combined with Boric Acid on Digestive Function, Immune Function, Harmful Gas and Heavy Metal Contents in Faeces of Fatteners.

The experiment aimed to investigate the effects of plant polysaccharides combined with boric acid on digestive function, immune function and harmful gas and heavy metal contents in the faeces of fatteners. For this study, 90 healthy crossbred fatteners were selected and randomly divided into five groups: the control group was fed with a basal diet (Con); experimental group I was fed with basal diet + 40 mg/kg boric acid (BA); experimental group II was fed with basal diet + 40 mg/kg boric acid + 400 mg/kg Astragalus polysaccharides (BA+APS); experimental group III was fed with basal diet + 40 mg/kg boric acid + 200 mg/kg Ganoderma lucidum polysaccharides (BA+GLP); and experimental group IV was fed with basal diet + 40 mg/kg boric acid + 500 mg/kg Echinacea polysaccharides (BA+EPS). Compared with Con, the average daily gain (ADG), the trypsin activities in the duodenum and jejunum, the IL-2 levels in the spleen, the T-AOC activities and GSH-Px contents in the lymph node of fattening were increased in the BA group (p < 0.05), but malondialdehyde content in the lymph and spleen, and the contents of NH3, H2S, Hg, Cu, Fe and Zn in the feces and urine were decreased (p < 0.05). Compared with the BA, the ADG, gain-to-feed ratio (G/F), the trypsin and maltase activities in the duodenum and jejunum were increased in the BA+APS (p < 0.05), and the T-SOD activities in the spleen and T-AOC activities in the lymph node were also increased (p < 0.05), but the H2S level was decreased in the feces and urine (p < 0.05). Compared with the BA, the ADG, G/F and the trypsin and maltase activities in the duodenum were increased in the BA+GLP and BA+EPS (p < 0.05), the activities of maltase and lipase in the duodenum of fatteners in the BA+GLP and the activities of trypsin, maltase and lipase in the BA+EPS were increased (p < 0.05). Gathering everything together, our findings reveal that the combined addition of boric acid and plant polysaccharides in the diet of fatteners synergistically improved their growth performance and immune status. That may be achieved by regulating the activity of intestinal digestive enzymes, improving the antioxidant function and then promoting the digestion and absorption of nutrients. Furthermore, the above results reduce the emission of harmful gases and heavy metals in feces and urine.

Transcriptomic Profiling of Meat Quality Traits of Skeletal Muscles of the Chinese Indigenous Huai Pig and Duroc Pig.

The Huai pig is a well-known indigenous pig breed in China. The main advantages of Huai pigs over Western commercial pig breeds include a high intramuscular fat (IMF) content and good meat quality. There are significant differences in the meat quality traits of the same muscle part or different muscle parts of the same variety. To investigate the potential genetic mechanism underlying the meat quality differences in different pig breeds or muscle groups, longissimus dorsi (LD), psoas major (PM), and biceps femoris (BF) muscle tissues were collected from two pig breeds (Huai and Duroc). There were significant differences in meat quality traits and amino acid content. We assessed the muscle transcriptomic profiles using high-throughput RNA sequencing. The IMF content in the LD, PM, and BF muscles of Huai pigs was significantly higher than that in Duroc pigs (p < 0.05). Similarly, the content of flavor amino acids in the three muscle groups was significantly higher in Huai pigs than that in Duroc pigs (p < 0.05). We identified 175, 110, and 86 differentially expressed genes (DEGs) between the LD, PM, and BF muscles of the Huai and Duroc pigs, respectively. The DEGs of the different pig breeds and muscle regions were significantly enriched in the biological processes and signaling pathways related to muscle fiber type, IMF deposition, lipid metabolism, PPAR signaling, cAMP signaling, amino acid metabolism, and ECM-receptor interaction. Our findings might help improve pork yield by using the obtained DEGs for marker-assisted selection and providing a theoretical reference for evaluating and improving pork quality.

Animal Model Studies, Antibiotic Resistance and Toxin Gene Profile of NE Reproducing Clostridium perfringens Type A and Type G Strains Isolated from Commercial Poultry Farms in China.

Poultry necrotic enteritis (NE) is a complex and multifactorial disease caused by Clostridium perfringens types. Earlier, the disease was prevented and/or controlled through the addition of in-feed antibiotics and antimicrobial growth promoters (AGPs). The ban on the use of these agents as feed additives has been a major reason for re-emergence of this disease leading to huge economic losses to the world poultry industry. Understanding the pathogenesis of NE by developing an effective experimental model remains challenging and lacks consistency owing to the involvement of several critical factors involved in causing lesions of disease in the field. In this study, locally characterized C. perfringens types, i.e., ACP (toxinotype A), and GCP (toxinotype G), obtained from NE outbreaks on commercial farms in China (2020-2022), were used to experimentally induce NE in Specific-Pathogen-Free (SPF) chicks. The lesion scores observed on day 20 were 1.9 ± 1.10 (GCP strain) and 1.5 ± 1.08 (ACP strain), and both had significant difference as compared to the control group. The inclusion of fishmeal in addition to oral clostridial dose, i.e., fishmeal (day 7 onward) + Clostridia (7.5 × 108 cfu/mL consecutively for 04 days) induced a lesion score of 2.0 ± 1.15 in respective groups. Use of coccidia (Eimeria necatrix) on day 9 followed by clostridia challenge enhanced the lesion scores to 2.5 ± 1.08 and 2.2 ± 1.23 for type G and type A strains, respectively. When both predisposing factors (coccidia + fish meal) were given together, i.e., fishmeal (day 7 onward) and coccidia (day 9) along with clostridia, the lesion scores were 3.2 ± 1.22 (GCP + coccidia + fish meal) and 3.0 ± 1.15 (ACP + coccidia + fish meal). These results were significantly different from group 1 (ACP) and 2 (GCP), in which only C. perfringens was used to induce NE. The clinical signs as well as histopathological lesions in experimentally induced groups were found similar as reported in the literature. The two type G strains identified in this study were also used for susceptibility testing against various drugs. Both strains were found to be resistant to amikacin, doxycycline, metronidazole, neomycin, nystatin, polymyxin B, streptomycin, and tetracycline. Variable susceptibility was seen against ceftriaxone, florfenicol, gentamicin, and kanamycin drugs. Amoxicillin, ampicillin, cefotaxime, ciprofloxacin, enrofloxacin, ofloxacin, and penicillin were effective drugs based upon their low level of resistance and therefore they might be preferred over other antimicrobial agents for proper treatment/prophylaxis of NE infections. Further studies are needed to study the pathogenesis of NE in detail in experimentally induced models along with continuous monitoring of the resistance pattern of C. perfringens strains in the field.

Establishment and Application of Indirect ELISAs for Detecting Antibodies against Goose Astrovirus Genotype 1 and 2.

Goose astrovirus (GAstV) was classified into GAstV-1 and GAstV-2, and both caused gosling viral gout. Recently, there has been no effective commercial vaccine to control the infection. It is important to establish serological methods to distinguish between the two genotypes. In this study, we reported the development and application of two indirect enzyme-linked immunosorbent assays (ELISAs) using the GAstV-1 virus and a recombinant GAstV-2 capsid protein as specific antigens to detect antibodies against GAstV-1 and GAstV-2, respectively. The optimal coating antigen concentration of indirect GAstV-1-ELISA and GAstV-2-Cap-ELISA was 1.2 µg/well and 125 ng/well, respectively. In addition, the antigen coating temperature and time, sera dilution and reaction time, and the dilution and reaction time of HRP-conjugated secondary antibody were optimized. The cut-off values were 0.315 and 0.305, and the analytical sensitivity was 1:6400 and 1:3200 for indirect GAstV-1-ELISA and GAstV-2-Cap-ELISA, respectively. The assays were able to differentiate specific sera against GAstVs, TUMV, GPV, and H9N2-AIV. The intra- and inter-plate variabilities of indirect ELISAs were less than 10%. The coincidence rate of positive sera was higher than 90%. The indirect ELISAs were further applied to test 595 goose serum samples. The results showed that the detection rates were 33.3% and 71.4% in GAstV-1-ELISA and GAstV-2-Cap-ELISA, respectively, and the co-detection rate was 31.1%, which indicates that the seroprevalence rate of GAstv-2 was higher than that of GastV-1, and the co-infection existed between GAstV-1 and GAstV-2. In summary, the developed GAstV-1-ELISA and GAstV-2-Cap-ELISA have high specificity, sensitivity, and reproducibility and can be used in the clinical detection of the antibody against GAstV-1 and GAstV-2.

Preparation of a new monoclonal antibody against nucleocapsid protein of swine acute diarrhea syndrome coronavirus and identification of its linear antigenic epitope.

Swine acute diarrhea syndrome coronavirus (SADS-CoV), which causes severe diarrhea in newborn piglets, was first identified in Southern China in 2017. Since the Nucleocapsid (N) protein in SADS-CoV is highly conserved and plays a key role in virus replication, it is often used as a target protein in scientific research. In this study, the N protein of SADS-CoV was successfully expressed, and a new monoclonal antibody (mAb), 5G12, against the protein was generated successfully. The mAb 5G12 can be used to detect SADS-CoV strains by indirect immunofluorescence assay (IFA) and western blotting. The mAb 5G12 epitope was located to amino acids 11 EQAESRGRK 19 by evaluating the antibody for reactivity with a series of truncated N protein segments. The biological information analysis showed that the antigenic epitope had a high antigenic index and conservation. This study will help further understand the protein structure and function of SADS-CoV and in the establishment of specific SADS-CoV detection methods.

Study of microencapsulated fatty acid antimicrobial activity in vitro and its prevention ability of Clostridium perfringens induced necrotic enteritis in broiler chicken.

BACKGROUND: Necrotic enteritis (NE) is an infectious intestinal disease caused by Clostridium perfringens (C. perfringens) that is now re-emerging and causing concern within the poultry industry. Previously, the supplementation of antibiotics in feed was the most popular control strategy against C. perfringens. However, with the ban on supplementing growth-promoting antibiotics in livestock feed, alternatives to antibiotics will be essential in order to control necrotic enteritis. A possible alternative to antibiotics could be the medium or long chain fatty acids (MCFA or LCFA) as these are able to destroy cell membranes which in turn results in the death of bacteria. In this study, the in vitro antimicrobial activity of different combinations with microencapsulated caprylic acid (C8: 0), capric acid (C10: 0), lauric acid (C12: 0) and myristic acid (C14: 0) against C. perfringens and in vivo control the NE-inducing C. perfringens in broiler chicken were analyzed. RESULTS: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) assay results revealed that three different combinations of medium/long chain fatty acids varied in antimicrobial activities against C. perfringens type A strain (CVCC52, quality control), C. perfringens type A strain (C8-1), C. perfringens type G strain (D25) and C. perfringens type G strain (MZ1). Specifically, combination of C12: 0 and C14: 0 (C12-14) showed the highest antimicrobial activity against the four strains of C. perfringens (MIC ≤ 12.5 µg/mL, MBC = 50 µg/mL), followed by the combination of C10: 0 and C12: 0 (C10-12) (MIC, MBC ≤ 50 µg/mL). The in vivo study, 189 of 818-crossbred chickens that were fed a wheat-based diet and randomly divided into nine groups, with six treatment groups supplemented with either a high dose (1 g/kg) or low dose (0.5 g/kg) of three combinations respectively. The remaining three groups comsisted of a positive group supplement with avilamycin (0.01 g/kg), an infected control and an uninfected control. All chickens were challenged with C. perfringens from day 14 to day 17, except those in the uninfected control group. On day 20, the duodenum and jejunum necrotic lesions scores were calculated and the results showed that there was significant decrease in the C12-C14 high dose group (1.43 ± 0.23, 0.48 ± 0.13) and the C10-12 high dose group (1.52 ± 0.19, 0.48 ± 0.11) compared to the infected group (2.86 ± 0.21, 1.20 ± 0.28). CONCLUSIONS: This finding indicated that dietary microencapsulated C12-C14 and C10-C12 could inhibit the growth of C. perfringens in chickens, which proves is viability to serve as an alternative to antibiotics used for necrotic enteritis caused by C. perfringens.

Hericium erinaceus polysaccharide improves the microstructure, immune function, proliferation and reduces apoptosis of thymus and spleen tissue cells of immunosuppressed mice.

In order to study the effect of Hericium erinaceus polysaccharide (HEP) on the immune and antioxidation functions of immunosuppressed mice. The control group received distilled water orally and the model and experimental groups I, II, and III received 0, 80, 160, and 320 mg/kg HEP respectively for a fortnight after re-molding with cyoclphosphnalide (CTX). Compared with the control group, the secretion of IL-2, IL-4, and IFN-γ, the activity or content of T-AOC, T-SOD, and GSH-PX, and the expression of PCNA mRNA in the thymus and spleen were reduced in immunosuppressed mice (P < .05 or P < .01). Compared with immunosuppressed mice, the levels of IL-2, IFN-γ, and GSH-PX and the PCNA mRNA expression of spleen and thymus were increased (P < .05 or P < .01), and the microstructure were also obviously improved in the experimental group III. Overall, 320 mg/kg of HEP significantly improved the immune and antioxidant functions.

An IgY Effectively Prevents Goslings from Virulent GAstV Infection.

Goose astrovirus (GAstV) leads to viscera and joints urate deposition in 1- to 20-day-old goslings, with a mortality rate of up to 50%, posing a severe threat to entire colonies; however, there is no efficient prevention and control method for GAstV infection. This study describes a prophylactic anti-GAstV strategy based on the specific immunoglobulin Y (IgY) from egg yolk. The specific IgY was produced by 22-week-old laying hens intramuscularly immunized with the inactivated GAstV three consecutive times, with 2-week intervals. The egg yolk was collected weekly after the immunization and the anti-GAstV IgY titer was monitored using an agar gel immune diffusion assay (AGID). The results revealed that the AGID titer began to increase on day 7, reached a peak on day 49, and remained at a high level until day 77 after the first immunization. The specific IgY was prepared from the combinations of egg yolk from day 49 to day 77 through PEG-6000 precipitation. Animal experiments were conducted to evaluate the effects of prevention and treatment. The result of the minimum prophylactic dose of the IgY showed that the protection rate was 90.9% when 2.5 mg was administrated. Results of the prevention and the treatment experiments showed prevention and cure rates of over 80% when yolk antibody was administered in the early stages of the GAstV infection. These results suggested that the specific IgY obtained from immunized hens with the inactivated GAstV could be a novel strategy for preventing and treating GAstV infection.

Establishment of a recombinase polymerase amplification (RPA) fluorescence assay for the detection of swine acute diarrhea syndrome coronavirus (SADS-CoV).

BACKGROUND: Swine acute diarrhea syndrome coronavirus (SADS-CoV) causes acute vomiting and diarrhea in piglets, leading to significant financial losses for the pig industry. Recombinase polymerase amplification (RPA) is a rapid nucleic acid amplification technology used under constant temperature conditions. The study established a real-time reverse transcription (RT)-RPA assay for early diagnosis of SADS-CoV.  RESULTS: The detection limit of the real-time RT-RPA was 74 copies/µL of SADS-CoV genomic standard recombinant plasmid in 95% of cases. The assay was performed in less than 30 min and no cross-reactions were observed with eight other common viruses that affect swine, including classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), pseudo rabies virus (PRV), swine influenza virus (SIV), seneca valley virus (SVA), transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV). The coefficient of variation (C.V.) values of the two standards dilutions and three positive clinical sample ranged from 2.95% to 4.71%. A total of 72 clinical fecal samples from swine with diarrheal symptoms were analyzed with the developed RT-RPA and quantitative RT-PCR. There was 98.61% agreement between the RT-RPA and the quantitative real-time PCR results. CONCLUSIONS: These results indicated that the developed RT-RPA assay had good specificity, sensitivity, stability and repeatability. The study successfully established a broadly reactive RT-RPA assay for SADS-CoV detection.

First Detection and Molecular Identification of Entamoeba bovis in Farm-Raised Sika Deer from Anhui Province, China.

BACKGROUND: Protozoans of Entamoeba spp. are one of the most common enteric parasites that infect humans and diverse animals including deer. PURPOSE: However, data regarding the prevalence and species/genotypes of Entamoeba spp. in deer in China is scarce. This study investigated the prevalence and species distribution of Entamoeba spp. in sika deer (Cervus nippon) in Anhui Province. METHODS: In our survey, 336 fecal samples were collected from five sika deer farms in different regions of Anhui Province. All samples were examined for the presence of Entamoeba spp. by PCR and phylogenetic analysis of the conserved 18S rRNA gene. RESULTS: 106/336 (31.5%) fecal samples were positive for Entamoeba spp. A statistically significant difference in the prevalence of Entamoeba spp. infection was observed between sampling farms (p < 0.001), and the prevalence of Entamoeba spp. in male and female sika deer showed no significant difference (p > 0.05). Sequence and phylogenetic analysis revealed the single species, E. bovis, was identified in this study. CONCLUSION: This is the first report about the identification of E. bovis in farm-raised sika deer in China, and these results expand our understanding of host range and species distribution of Entamoeba spp. in ruminants.

Molecular prevalence of Tetratrichomonas gallinarum and Trichomonas gallinae in three domestic free-range poultry breeds in Anhui Province, China.

Tetratrichomonas gallinarum and Trichomonas gallinae can colonize the alimentary tract of domestic birds. However, little information is available on the epidemiology of the two trichomonad species in domestic free-range poultry in China. In this study, the occurrence and genetic characteristic of T. gallinarum and T. gallinae among free-range chickens, ducks, and geese in Anhui Province, China, were investigated. The 1910 fecal samples collected from 18 free-range poultry farms throughout Anhui Province were examined for the presence of T. gallinarum and T. gallinae by PCR and sequence analysis of the small subunit (SSU) rRNA gene of T. gallinarum and ITS1-5.8S-ITS2 sequence of T. gallinae. The overall occurrence of T. gallinarum in poultry was 1.2% (22/1910), with infection rates of 2.1% (17/829) in chickens, 0.2% (1/487) in ducks, and 0.7% (4/594) in geese. The constructed phylogeny tree using the concatenated ITS1-5.8S-ITS2 region and SSU rRNA indicated the T. gallinarum isolates detected in this study were closely related to previously defined genogroups A, D, and E, respectively. Nine (0.5%) fecal samples were positive for T. gallinae, with infection rates of 0.8% (7/829) in chickens, 0.4% (2/487) in ducks, and 0% (0/594) in geese. Sequence and phylogenetic analysis showed that four T. gallinae ITS1-5.8S-ITS2 sequences obtained from chicken feces and one duck fecal sample belonged to genotype ITS-OBT-Tg-1. This is the first report of the prevalence and genetic characterization of T. gallinarum and T. gallinae in free-range chickens, ducks, and geese in China.

Prevalence and Molecular Identification of Entamoeba spp. in Non-human Primates in a Zoological Garden in Nanjing, China.

Objective: Entamoeba spp. are globally distributed zoonotic parasites that infect various hosts, among which non-human primates (NHPs) have been identified as one of the most common hosts of these parasites. Consequently, the infections of Entamoeba spp. in captive NHPs from Nanjing Hongshan Forest Zoo in China were investigated in order to assess their zoonotic potential. Methods: A total of 120 fresh fecal samples, including 19 species of NHPs, were collected from four breeding bases of the zoo from May to June 2019. The infections of six species of Entamoeba spp. were detected by PCR using the 16S or 18S rDNA-specific primers, and the positive samples were sequenced and analyzed. Results: Entamoeba spp. were detected as positive in 59 NHPs fecal samples (49.17%), including five Entamoeba species: Entamoeba histolytica (7.50%), E. dispar (22.50%), E. coli (22.50%), E. chattoni (10.00%) and E. nuttalli (1.67%). Infection with one Entamoeba species was more common (35%) than co-infections (13.33%) or infections with three Entamoeba species (0.83%). There was a significantly higher prevalence rate of Entamoeba spp. in the species Pongo pygmaeus and Macaca mulatta than in Papio sp., Mandrillus sphinx, and Saimiri sciureus. Conclusion: Entamoeba spp. are highly prevalent in the NHPs raised in Nanjing Hongshan Forest Zoo. Therefore, attention should be paid to the development of containment strategies of Entamoeba spp. in this zoological garden.

Prevalence and molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi from large-scale cattle farms in Anhui Province, China.

To investigate the prevalence of Cryptosporidium spp. and Enterocytozoon bieneusi from large-scale cattle farms in Anhui Province, 955 fecal samples were collected from 16 cattle farms from March to October 2018, which included six dairy farms (526), seven yellow cattle farms (323), and three water buffalo farms (106) in different regions of Anhui Province. PCR was conducted on all fecal samples using the 18S ribosomal RNA of Cryptosporidium spp. and internal transcribed spacer gene of E. bieneusi to detect these two pathogens, and the positive samples were sequenced and analyzed. The results showed that 23 (2.4%) and 40 (4.2%) out of the 955 samples were positive for Cryptosporidium spp. and E. bieneusi, respectively. There were 11 (2.1%), 10 (3.1%), and 2 (1.9%) positive samples of Cryptosporidium spp. and 16 (3.0%), 23 (7.1%), and 1 (0.9%) positive samples of E. bieneusi collected from dairy cattle, yellow cattle, and water buffalo, respectively, and no co-infection was identified in this study. All positive samples of Cryptosporidium spp. were C. andersoni with some variations. Ten E. bieneusi genotypes were obtained, including two known genotypes, J and CHN11, and eight new genotypes, named AHDC1 and AHYC1-7. The genotype CHN11 belonged to zoonotic Group 1, and the other nine genotypes belonged to Group 2, which is mainly documented in ruminants. These results indicated that Cryptosporidium spp. and E. bieneusi infections were present in large-scale cattle farms in Anhui Province. Therefore, attention should be paid to the development of containment strategies of these two pathogens in cattle.

Transcriptome Profiling of Duodenum Reveals the Importance of Boron Supplementation in Modulating Immune Activities in Rats.

As an essential trace element, appropriate boron supplementation can promote immune function of animals. To illustrate the effects of boron in a rat model, RNA-Seq was conducted for the RNA from duodenum after treatment with different concentration of boron in which boron was given in the form of boric acid. More than 47 million reads were obtained in 0, 10, and 320 mg/L boron (0, 57.21, and 1830.66 mg/L boric acid) treatment groups that produced 58 965 402, 48 607 328, and 46 760 660 clean reads, respectively. More than 95% of the clean reads were successfully matched to the rat reference genome and assembled to generate 32 662 transcripts. A total of 624 and 391 differentially expressed candidate genes (DEGs) were found between 0 vs.10 and 0 vs. 320 mg/L boron comparison groups. We also identified transcription start site, transcription terminal site, and skipped exons as the main alternative splicing events. GO annotations revealed most of DEGs were involved in the regulation of immune activity. The DEGs were enriched in influenza A, herpes simplex infection, cytosolic DNA-sensing pathway, and antigen processing and presentation signaling pathways. The expression levels of genes enriched in these signaling pathways indicate that lower doses of boron could achieve better effects on promoting immune response in the duodenum. These effects on the immune system appear to be mediated via altering the expression patterns of genes involved in the related signaling pathways in a dose-dependent pattern. These data provide more insights into the molecular mechanisms of immune regulation in rats in response to dietary boron treatment.

Molecular prevalence and characterization of Cryptosporidium in domestic free-range poultry in Anhui Province, China.

Free-range chickens might mediate the spread of Cryptosporidium oocysts to humans and other animals. Few studies have evaluated the prevalence of Cryptosporidium species in domestic free-range poultry in China. Here, we characterized the prevalence and distribution of species and genotypes of Cryptosporidium in domestic free-range chickens, ducks, and geese in Anhui Province, China. A total of 1910 fresh fecal samples from three poultry species were examined from 18 free-range poultry farms by nested PCR and analysis of the Cryptosporidium SSU rRNA gene. The overall prevalence of Cryptosporidium species was 2.9% (55/1910), with infection rates of 1.3% (11/829) in chickens, 7.3% (36/487) in ducks, and 1.4% (8/594) in geese. C. baileyi (0.6%), C. meleagridis (0.2%), C. galli (0.2%), and C. xiaoi-like genotype (0.2%) were identified in chickens, and only C. baileyi was identified in ducks and geese, with infection rates of 7.4% and 1.3%, respectively. C. baileyi was the most prevalent species. Sequencing of the GP60 gene revealed that the C. meleagridis isolates belonged to the IIIbA26G1R1b subtype. This is the first study to document C. galli and C. xiaoi-like genotype in domestic free-range chickens in China. These findings expand the range of avian hosts known for Cryptosporidium and highlight the need for additional studies to characterize the diversity of Cryptosporidium in avian species.

Seroprevalence of influenza A (H9N2) virus infection among humans in China: A meta-analysis.

Herein, we conducted a meta-analysis aimed at comprehensively assessing avian influenza A (H9N2) virus infection seroprevalence and infection-related risk factors among humans in China. We reviewed published studies pertaining to H9N2 seroprevalence of in China from inception to March 20, 2020, with PubMed, Clinical Trial, VIP, CNKI and databases being used to identify English and Chinese articles. After excluding the incomplete literature and data, 45 studies about risk factor of human H9N2 viral infections in China were analyzed by systematic review and meta-analysis. Our results showed that 45 studies (59,590 total patients) met the inclusion criteria. Overall H9N2 infection seroprevalence in China was estimated to be 5.56% (95%CI = 3.88-7.28), while that from central China the seroprevalence was 22.72% (95%CI = 12.18-33.84), with this prevalence being greater than that observed in other regions. H9N2 infection seroprevalence was related to sampling time, testing methodology, gender, and other demographic factors. This review will provide a basis for further understanding the risk factors of H9N2 infections in China, and it is necessary to study how to formulate strict and targeted measures to prevent the spread of the virus.

Surveillance of multiple subtype specific antibodies against avian influenza viruses among egg yolk in wild ducks from northeast China, 2017-2019.

Over the past decade, various avian influenza viruses have been isolated from wild ducks found in the northeast of China. To monitor the prevalence of multiple subtype specific AIVs antibodies, 1705 wild ducks' eggs from six wetlands of northeast China were analyzed for surveillance of H1, H3, H5, and H7 AIVs antibodies by c-ELISA and HI test from Jan 2017 to Dec 2019. The results show that the combined frequency of multiple subtype specific AIVs antibodies were H1 (12.32%), H3 (8.15%), H5 (2.05%), and H7 (3.46%) respectively. Therefore, a detailed analysis of the geographical distribution of AIVs in China, and the risk factors for human infection is of vital importance. This study provides basic data for other researchers to deeply study AIVs distribution characteristics, and for governments to develop detailed measures to control the spread of AIVs.

Effect of Boron on Microstructure, Immune Function, Expression of Tight Junction Protein, Cell Proliferation and Apoptosis of Duodenum in Rats.

Boron is an essential trace element for animals. Appropriate boron supplementation can produce beneficial effects on the animal body, while a high dose of boron has adverse and even toxic effects. Our aim was to investigate the impact of different doses of boron on the microstructure of duodenum in rats, expression of secretory immunoglobulin A (SIgA) and tight junction protein, cell proliferation and apoptosis. Eighty newly weaned clean Sprague-Dawley (SD) rats were given distilled water supplemented with 0, 10, 20, 40, 80, 160, 320, and 640 mg/L of boron for 60 days. We found that supplementation of 40 and 80 mg/L boron could increase the height of duodenal villi and the crypt depth, the number of intraepithelial lymphocytes (IELs) and goblet cells, the expression of SIgA, Zonula occludens-1 (ZO-1) and occludin, and proliferating cell nuclear antigen (PCNA) in duodenum of rats; decrease expression of Caspase-3 mRNA and the number of Caspase-3-positive cells, but supplementation of 320 and 640 mg/L boron could have the opposite effect in these indexes. The results showed that supplemented with 40 and 80 mg/L of boron could improve the structure and function of duodenum, while supplemented with 320-640 mg/L had a significant inhibitory effect.

GPR30 mediated effects of boron on rat spleen lymphocyte proliferation, apoptosis, and immune function.

Supplementing different quantities of boron can significantly affect immune function in rat spleen, but the mechanism of action behind this effect remains unclear. Our purpose was to study the involvement of the estrogen membrane receptor GPR30 in the effect of boron on the proliferation, apoptosis, and immune function of rat spleen lymphocytes. Results showed that the addition of 0.4 mmol/L boron had a beneficial effect on the immune function and proliferation of spleen lymphocytes, but the addition of 40 mmol/L boron had opposite effect. After using G-15 to selectively inhibit GPR30, the proportions of CD4+ and CD8+ T cells, the content of IL-2 and IFN-γ, and the expression of PCNA protein were significantly decreased, while lymphocyte apoptosis rate increased significantly (p < 0.05 or p < 0.01). After G-15 treatment, the addition of 0.4 mmol/L boron had no effects on T cell subsets, lymphocyte proliferation, PCNA protein expression, and IgG and cytokine content (P > 0.05), while the addition of 40 mmol/L boron did not change the effects on lymphocyte subsets, proliferation and apoptosis. The results suggested that GPR30 mediates the effects of 0.4 mmol/L boron boron on the proliferation, apoptosis and immune function of spleen lymphocytes.

The first report of Cryptosporidium testudinis in Chinese alligators (Alligator sinensis) in China.

Several Cryptosporidium species that infect reptiles, especially squamates, are well described, but there is limited data about Cryptosporidium species infecting crocodilians. In this study, we assess the occurrence of intestinal parasites using traditional microscopic examination and describe the prevalence and Cryptosporidium species in the captive-bred Chinese alligators (Alligator sinensis) in eastern China using molecular methods. The results of microscopic examination showed that no intestinal parasites were detected among the 491 fecal samples examined from the Chinese alligators. The overall prevalence for Cryptosporidium was 0.41% (2/491) by PCR detection using the SSU rRNA locus. Sequence and phylogenetic analysis of the SSU rRNA, COWP, and actin genes revealed the presence of Cryptosporidium testudinis, which has been isolated primarily from chelonians. This is the first detection of the specific DNA of C. testudinis in the feces of the Chinese alligator. This study expands our knowledge of the Cryptosporidium species involved in crocodiles, and more extensive studies are necessary to confirm the validity of C. testudinis in crocodiles.