BMC Veterinary Research最新文献

This research investigates the effects of dietary supplementation with Ecobiol plus^® (Bacillus amyloliquefaciens CECT5940) on the growth performance, physiological responses, oxidative stress, and immune status of Nile tilapia (Oreochromis niloticus) fingerlings revealed to Aeromonas hydrophila. A total of 525 Nile tilapia fingerlings, averaging 30.00 ± 5.00 g in initial weight, were randomly divided into four groups (control and three experimental groups), each with three replicates of 25 fish. Ecobiol plus^® was integrated in the diet at concentrations of 0.0 (control), 0.1, 0.2, and 0.4 g/kg feed. Fish were fed at 3% of their biomass daily, with biweekly adjustments based on growth. The feeding trial lasted 8 weeks, followed by a 15-day challenge with Aeromonas hydrophila to evaluate immune responses and survival outcomes. The group receiving 0.4 g/kg of Ecobiol plus^® exhibited the most significant improvements in growth performance, including higher weight gain, specific growth rate, and feed conversion efficiency (p < 0.05). Blood and biochemical assessments indicated increased hemoglobin, total protein, and globulin levels, reflecting improved physiological and immunological conditions. Additionally, lysozyme activity and phagocytic response were markedly enhanced, demonstrating the probiotic's immune-boosting potential. Histopathological evaluations revealed reduced gut, gills, and hepatopancreas lesions, especially in groups with higher supplementation levels. Fish in Group T4, fed with 0.4 g/kg Ecobiol plus^®, achieved the best growth performance, with a final weight of 77.96 ± 5.53 g, a weight gain of 42.46 ± 3.18 g, and a specific growth rate (SGR) of 1.51%/day, compared to the control group (T1) with a final weight of 75.26 ± 3.87 g, weight gain of 35.76 ± 2.08 g, and SGR of 1.24%/day. Survival rates considerably increased in the treated groups, with T4 exhibiting the highest rate of 96.00%, followed by T2 (94.68%), T3 (92.00%), and T1 (81.32%). Additionally, the LD50 of A. hydrophila was determined to be 3 × 10⁷ CFU/mL, underscoring the protective effect of Ecobiol plus^® in enhancing fish immunity and resilience against bacterial challenges. These results suggest that Ecobiol plus^® can be a natural, antibiotic-free additive to strengthen growth and disease resistance in Nile tilapia. The optimal inclusion level of Ecobiol plus^® is 0.4 g/kg for maximum benefit.

Background: Parvoviridae is a family of single-stranded linear DNA viruses whose members infect both vertebrate and invertebrate species of animals, causing diseases of various systems and often associated with pathology of the gastrointestinal tract. Additionally, parvoviruses are known to induce illnesses causing diarrhea in various avian species as well; however, data on their occurrence and pathology in pigeons is scarce.

Results: In this study, we developed molecular biology methods to detect and quantify parvovirus genetic material in samples acquired from racing pigeons of different health status. Our intention was to determine a connection between the presence of the virus and the occurrence of clinical signs in sampled birds. The results of quantitative analysis indicate no direct association of parvoviruses with the manifestation of enteric disease in pigeons. High-throughput sequencing was performed on samples testing positive in quantitative PCR with TaqMan probe and in digital droplet PCR. It allowed us to assemble two coding-complete pigeon parvovirus genomes, one belonging to new species and referred to as pigeon parvovirus 2, and the second which is a member of species Aveparvovirus columbid1. Additionally, we analyze two coding-complete genomic sequences acquired from pigeon feces in USA, one representing species Aveparvovirus columbid1 and one being a member of Chaphamaparvovirus genus in Hamaparvovirinae subfamily.

Conclusions: This is the first report of parvovirus in pigeons outside Asia. The findings of our research emphasize the need to further explore the poorly understood biology and pathology of pigeon parvoviruses.

Background: Bovine viral diarrhoea virus genotype 1 (BVDV-1) and bluetongue virus (BTV) are potent viral pathogens that may be transmitted through semen, resulting in the spread of diseases via artificial insemination. Thus, establishing an early detection method for BVDV-1 and BTV infection is important for the trading of semen. In this study, we developed two RT‒ddPCR methods to detect BVDV-1 and BTV, and each method was evaluated for repeatability, limit of detection and specificity. The sensitivity of these methods was compared with that of RT‒qPCR (WOAH) by analysing clinical samples.

Results: The RT‒ddPCR results revealed that both methods exhibited good repeatability at low concentrations, with detection limits of 1.05 copies/µL and 0.662 copies/µL per reaction for BVDV-1 and BTV, respectively; additionally, both methods exhibited high specificity and did not exhibit cross-reaction with other important semen-transmitted pathogens. Eighty bovine semen samples and twenty mixed semen samples were tested. The results revealed that the positivity rates of BVDV-1 and BTV RT‒ddPCR (25% and 23%, respectively) were greater than those of RT‒qPCR (19% and 18%, respectively).

Conclusions: RT‒ddPCR was highly sensitive for detecting low concentrations of BVDV-1 and BTV in clinical samples and could be a good supplement for qPCR testing.

Background: Coccidia are among the primary pathogens causing diarrhea and even fatalities in lambs. With the increasing use of chemical drugs to treat coccidiosis, the problem of drug resistance is becoming more and more threatening. Therefore, there is an urgent need to identify novel alternative drugs for the treatment of the lamb coccidia. In this study, the effect of different doses and extraction methods of Artemisia annua (A. annua) on anticoccidial activity and growth performance was assessed by oocysts output (OPG), fecal index, average daily gain (ADG) and the new production value of experimental lambs. High-throughput sequencing technology was employed to investigate the effect of A. annua on the intestinal microbiota and metabolites of lambs afflicted with coccidiosis.

Results: The results revealed that all A. annua treatment groups exhibited good anticoccidial effects. According to the soft stool index and ADG analysis, the Low-dose A. annua (AL) and A. annua alcohol extract (AA) groups demonstrated a better overall effect. The microbiota and metabolites of lambs changed after A. annua was administered. Unclassified_Muribaculaceae exhibited a significant positive correlation with ADG (P < 0.05) and a negative correlation with OPG, although the latter was not statistically significant (P > 0.05). Alistipes displayed a significant negative correlation with ADG (P < 0.05), and a positive correlation with OPG (P > 0.05). Additionally, UCG 005 exhibited a highly significant negative correlation with OPG (P < 0.01).

Conclusion: The above results demonstrated that AL and AA groups had more effective anticoccidial action. Unclassified_Muribaculaceae could be employed as a suitable probiotic to enhance weight gain in lambs, while UCG-005 could inhibit intestinal Eimeria colonization in lambs. Alistipes may serve as a biomarker for predicting the risk of intestinal coccidia outbreaks in lambs. A. annua induced significant changes in gut microbiota, accompanied by corresponding changes in metabolites. These differences in gut microbiota and metabolites provide valuable insights for subsequent research on the mechanisms underlying anticoccidial action.

Escherichia coli has become a common causative agent of infections in animals, inflicting serious economic losses on livestock production and posing a threat to public health. Escherichia coli infection is common and tends to be complex in Xinjiang, a major region of cattle and sheep breeding in China. This study aims to explore the current status and molecular characteristics of Escherichia coli infection in cattle and sheep in Xinjiang, as part of the disease prevention and control strategy. Herein we isolated Extraintestinal pathogenic Escherichia coli (ExPEC) from the liver, spleen, lung, heart, and lymph nodes of infected cattle and sheep (Xinjiang, China), and phylogenetic grouping, serotyping, and multilocus sequence typing were performed to determine epidemic and molecular characteristics. We also assessed their biofilm formation ability. A total of 132 strains of ExPEC were identified from diseased cattle and sheep, belonging to 7 phylogenetic groups. A and B1 are advantageous groups. Further, 22 serogroups were found, with O101 (26/132), O154 (14/132), and O65 (8/132) being the predominant ones. Among the seven sequence types identified by multilocus sequence typing, ST10 was the most common, followed by ST23 and ST457. Of 132, 105 (79.5%) strains were able to form biofilms: 15 strains (11.4%) were strong, 28 (21.2%) were medium, and 62 (47%) were weak biofilm producers. These findings will contribute to a better understanding of the molecular epidemiology of ExPEC in Xinjiang, China, and can be applied to the development, prevention, and disease control of future diagnostic tools and vaccine.

Background: Prostaglandin E2 (PGE2) is vital for embryo implantation and decidualization. Whether COX2/mPGES1/PGE2 pathway is essential for mouse and human decidualization remains unclear.

Results: This study showed that mPGES1 was highly expressed in the mouse uterus's subluminal stromal cells at the implantation site. COX2-specific inhibitor Valdecoxib and mPGES1 selective inhibitor MK886 were used to analyze the roles of mPGES1 and COX2 during mouse and human decidualization. During mouse in vitro decidualization, decidua/trophoblast prolactin-related protein (Dtprp) expression was significantly suppressed by Valdecoxib and MK886. Under human in vitro decidualization, mPGES1 significantly increases, while both cPGES and mPGES2 remain unchanged. PGE2-mediated upregulation of insulin growth factor binding protein 1 (IGFBP1) was significantly inhibited by Valdecoxib and MK886.

Conclusions: Our findings suggest the involvement of COX2/mPGES1/PGE2 pathway in both mouse and human decidualization.

Background: Peste des petits ruminants virus (PPRV) is currently the only member of the Morbillivirus caprinae species within the genus Morbillivirus of the family Paramyoxviridae. PPRV causes a highly contagious disease in small ruminants, especially goats and sheep. Succinylation is a newly identified and conserved modification and plays an important role in host cell response to pathogen infection. However, the extent and function of succinylation in Vero cells during PPRV infection remains unknown.

Results: In this study, a global profile of the succinylome in Vero cells infected with PPRV Nigeria 75/1 vaccine strain (PPRVvac) was performed by dimethylation labeling-based quantitative proteomics analysis. A total of 2633 succinylation sites derived from 823 proteins were quantified. The comparative analysis of differentially succinylated sites revealed that 228 down-regulated succinylation sites on 139 proteins and 44 up-regulated succinylation sites on 38 proteins were significantly modified in response to PPRVvac infection, seven succinylation motifs were identified. GO classification indicated that the differentially succinylated proteins (DSuPs) mainly participated in cellular respiration, biosynthetic process and transmembrane transporter activity. KEGG pathway analysis indicated that DSuPs were related to protein processing in the endoplasmic reticulum. Protein-protein interaction networks of the identified proteins provided further evidence that various ATP synthase subunits and carbon metabolism were modulated by succinylation, while the overlapped proteins between succinylation and acetylation are involved in glyoxylate and dicarboxylate metabolism.

Conclusions: The findings of the present study provide the first report of the succinylome in Vero cells infected with PPRVvac and provided a foundation for investigating the role of succinylation alone and its overlap with acetylation in response to PPRVvac.

Animals infected with mycoplasma pneumoniae not only develop respiratory diseases, but also cause digestive diseases through the lung-gut axis mediated by the intestinal flora, and vice versa. Antimicrobial peptides are characterized by their bactericidal, anti-inflammatory, and intestinal flora-regulating properties. However, the effect of cecropin AD (CAD) against mycoplasma pneumonia remains unclear. To investigate the anti-inflammatory effect of CAD on mycoplasma pneumonia and the associated mechanism, mice were infected with Mycoplasma capricolum subsp. Capripneumoniae(Mccp) to elicit lung inflammation, followed by oral administration of CAD via gavage. The findings showed that mice receiving twice injections of 2.08 × 10⁸ copies of Mccp suffered significant pathological damage to their lungs and colons. Additionally, there was a notable upsurge in inflammatory factors within the affected tissues. 16 S rDNA sequencing revealed alterations in the colonic microbiota, including a decrease in the abundance of beneficial bacteria such as Corynebacterium_glutamicum and Candidatus_Saccharimonas, and an increase in the abundance of potential pathogens like Lachnospiraceae_NK4A136_group and Escherichia-Shigella. As a result, there were abnormal rises in lipopolysaccharide (LPS) levels in both colonic content and blood. Moreover, CAD treatment reversed the microbial dysbiosis and decreased the LPS levels induced by Mccp, thereby suppressing the activation of the TLR-4/NF-κB pathway and the Fas/FasL-caspase-8/-3 pathway. Consequently, this significantly mitigated the morphological and functional damage to the lungs and colons caused by Mccp. The findings offer novel insights and approaches for the clinical management of Mccp infections.

Background: Actinobacillus pleuropneumoniae is a prevalent respiratory pathogen causing substantial economic losses in swine production worldwide. The bacterium's ability to rapidly develop antimicrobial resistance (AMR) poses a significant challenge to effective treatment and control. In Poland, limited data on A. pleuropneumoniae serotype distribution and AMR patterns hinder evidence-based treatment strategies. This study examined the serotype diversity and AMR patterns of A. pleuropneumoniae isolates from porcine pleuropneumonia outbreaks in northeastern Poland between 2019 and 2024, providing crucial information for regional veterinary practices and antimicrobial stewardship efforts.

Results: Analysis of 119 isolates from 67 farms demonstrated the predominance of serotype 2 (65.5%), followed by serogroups 3, 6, 8 (18.5%) and 1, 9, 11 (15.1%). This distribution differs from recent trends in other European countries, suggesting regional epidemiological variations. High resistance rates were observed for tylosin (55.5%), gentamicin (36.1%), doxycycline (32.8%), and sulfamethoxazole/trimethoprim (26.1%). Multidrug resistance fluctuated between 14.3% and 21.9% over the study period, with no clear linear trend. From 2022 onwards, strains exhibiting resistance to seven or more antimicrobials, including cephalosporins, emerged, marking a significant shift in resistance profiles. Temporal analysis revealed diverse resistance patterns, with significant increases in some antimicrobials (e.g., sulfamethoxazole/trimethoprim, p = 0.001) and stability in others (e.g., tetracycline, p = 0.890). Notably, several antimicrobials, including florfenicol and colistin, maintained 100% efficacy against all isolates throughout the study period.

Conclusions: The findings highlight the dynamic nature of AMR development in A. pleuropneumoniae and underscore the need for ongoing surveillance in the region. The emergence of highly resistant strains, particularly those resistant to cephalosporins, raises concerns about future treatment options. These results can guide evidence-based treatment strategies and enhance antimicrobial stewardship efforts in regional swine production. Furthermore, the study emphasizes the importance of local AMR data in guiding antimicrobial use policies and the need for a coordinated approach to combat AMR in veterinary medicine.

The effects of Acremonium terricola culture (ATC) on production performance, serum biochemical parameters, egg quality and amino acid contents in the yolk of eggs of Beijing You-chicken were conducted in the current study. A total of 216 Beijing You-chickens (330 days old) were randomly divided into 2 groups. The control group (CON) was fed a corn-soybean-based diet, and the experimental group was fed a basal diet supplemented with 0.20% ATC. The pretest period was 7 d, and the experiment period was 8 weeks. The production performance, serum biochemical parameters, egg quality, and the concentrations of amino acids in the yolk of eggs were measured at the 4 weeks (FW, the first stage) and the 8 weeks (EW, the second stage) of the experiment, respectively. Compared with the CON group, there were no significant differences (P > 0.05) in the production performance of the experimental group at the end of four- and eight-week periods of study. The concentration of serum LH, FSH and E2 increased significantly for the ATC group, at both time periods when compared to CON group, while the triglyceride (TG) content was only increased significantly (P < 0.05) in the first stage. The average egg weight, albumen height, and Haugh unit representing egg quality of Beijing You-chickens in the experimental group were increased significantly (P < 0.05) compared with the CON group at both time periods, while the egg shape index and yolk weight were only increased significantly (P < 0.05) in the second stage. The protein content in the yolk was increased significantly at both time periods (P < 0.05). Levels of lecithin and Vitamin A in yolks of the ATC supplemented group increased significantly (P < 0.05) compared to the CON group, at both FW and EW, respectively. The contents of aspartic acid, threonine, methionine, leucine, and arginine were increased significantly in the first stage. In addition, the contents of threonine, glutamine, and valine were increased significantly in the second stage (P < 0.05). Our results suggest that dietary supplementation with 0.20% ATC improves serum biochemical parameters and egg quality in Beijing You-chickens. Future studies should focus on optimizing ATC dosage and exploring its underlying mechanisms for enhanced poultry production.