Antimicrobials Alternatives for the Prevention and Treatment of Veterinary Infectious Diseases: Volume II

Editors

Kun Li

Nanjing Agricultural University

Amjad Islam Aqib

Cholistan University of Veterinary and Animal Sciences

Ambreen Ashar

North Carolina State University

Impact

Protection of mice against challenge with infectious SVA at 28 d post-immunization. (A) Relative SVA levels in heart, liver, spleen, lung, kidney, and duodenal tissues of mice on day 14 after SVA challenge via inoculation. (B) Pathologic examination of mouse hearts after SVA inoculation. A: SVA-PBS; B: SVA-ISA; C: SVA-IMS; D: PBS; E: SVA-GEL; F: SVA-LV. Magnification 40×. (C) Light microscopic appearance of the heart of the SVA-infected mice or mice in control group (von Kossa stain, original magnification ×40).

Original Research

03 May 2024

Development and evaluation of inactivated vaccines incorporating a novel Senecavirus A strain-based Immunogen and various adjuvants in mice

Bingliang Wang

, 10 more and

Yungang Lan

1,859 views

0 citations

Original Research

28 March 2024

Cecropin AD reduces viral load and inflammatory response against H9N2 avian influenza virus in chickens

Taiming Zhang

, 6 more and

Ge Hu

1,359 views

1 citations

Histopathology in Salmonella-induced cecal lesions. (A) Mild cecal lesions with mild neutrophilic infiltrate in pigs were fed a control standard diet supplemented with an amino acid blend, followed by oral inoculation with Salmonella enterica serovar Typhimurium (AA+ST group). (B) Normal cecum in control pigs. (C) Severe cecal lesions with moderate neutrophilic infiltrate and ulceration (arrows) in pigs were oral inoculation with Salmonella enterica serovar Typhimurium without supplementation with an amino acid blend (ST group).

Original Research

13 March 2024

The in vitro and in vivo anti-inflammatory and anti-oxidative effects of an amino acid blend supplemented feed on pigs experimentally challenged with Salmonella Typhimurium

Sehyeong Ham

, 6 more and

Chanhee Chae

1,249 views

0 citations

Original Research

14 February 2024

Biosecurity measures to control hepatitis E virus on European pig farms

Tamino Dubbert

, 19 more and

Elke Burow

Hepatitis E virus (HEV) genotype 3 is a prevalent zoonotic pathogen in European pig farms, posing a significant public health risk primarily through the foodborne route. The study aimed to identify effective biosecurity measures for controlling HEV transmission on pig farms, addressing a critical gap in current knowledge. Utilizing a cross-sectional design, fecal samples from gilts, dry sows, and fatteners were collected on 231 pig farms of all farm types across nine European countries. Real-time RT-PCR was employed to test these samples for HEV. Simultaneously, a comprehensive biosecurity questionnaire captured data on various potential measures to control HEV. The dependent variable was HEV risk, categorized as lower or higher based on the percentage of positive pooled fecal samples on each farm (25% cut-off). The data were analyzed using generalized linear models (one for finisher samples and one for all samples) with a logit link function with country and farm type as a priori fixed factors. The results of the final multivariable models identified key biosecurity measures associated with lower HEV risk, which were the use of a hygienogram in the breeding (OR: 0.06, p = 0.001) and/or fattening area after cleaning (OR: 0.21, p = 0.019), the presence of a quarantine area (OR: 0.29, p = 0.025), testing and/or treating purchased feed against Salmonella (OR: 0.35, p = 0.021), the presence of other livestock species on the farm, and having five or fewer persons in charge of the pigs. Contrary to expectations, some biosecurity measures were associated with higher HEV risk, e.g., downtime of 3 days or longer after cleaning in the fattening area (OR: 3.49, p = 0.005) or mandatory handwashing for farm personnel when changing barn sections (OR: 3.4, p = 0.026). This novel study unveils critical insights into biosecurity measures effective in controlling HEV on European pig farms. The identification of both protective and risk-associated measures contributes to improving strategies for managing HEV and underscores the complexity of biosecurity in pig farming.

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Bar graph showing (A) EC H2O2 concentration measured by fluorometric assay. (B) MDA concentration measured by colorimetric assay. Chicken hepatocyte-non-parenchymal cell co-cultures were treated with three different concentrations of cecropin A (CecA) alone and in combination with polyinosinic-polycytidylic acid (Poly I:C). Green color refers to treatment groups without the addition of Poly I:C, while orange color refers to treatment with Poly I:C. Columns represent means ± SEM (n = 6/treatment group). Cec-1 = 1 μg/mL CecA, Cec-2 = 3.125 μg/mL CecA, Cec-3 = 6.25 μg/mL CecA, PI:C = 50 μg/mL Poly I:C. Cells receiving none of the treatments are considered as Control. Asterisks indicate significant differences when treatment groups Cec-1, Cec-2, Cec-3 and PI:C were compared to Control, whereas combinations of Poly I:C and CecA (PI:C + Cec-1, PI:C + Cec-2, PI:C + Cec-3) were compared to the group PI:C. Hashtags indicate significant differences when comparing combinations of Poly I:C and CecA to Control. *p < 0.05, **p < 0.01, and ##p < 0.01.

Original Research

01 March 2024

Cecropin A: investigation of a host defense peptide with multifaceted immunomodulatory activity in a chicken hepatic cell culture

Rege Anna Márton

, 6 more and

Gábor Mátis

1,178 views

2 citations

Evaluation of the effects of essential oils on cytokine production in bovine turbinate cell lines. Different uppercase letters indicate significantly different means (p < 0.05). The values are the means obtained from three independent experiments performed on different days. Different uppercase letters indicate significantly different means (p < 0.05).

Original Research

07 February 2024

Screening and selection of essential oils for an intranasal spray against bovine respiratory pathogens based on antimicrobial, antiviral, immunomodulatory, and antibiofilm activities

Samat Amat

, 5 more and

Sheela Ramamoorthy

Introduction: The rise in antibiotic resistant pathogens associated with bovine respiratory disease (BRD) poses a serious challenge, particularly to the beef feedlot industry, as they currently depend on antibiotics to prevent BRD to mitigate the financial burden (approx. $1 billion annual loss) inflicted by BRD-associated high mortality and morbidity in feedlot cattle. Thus, there is an impetus need for the development of antimicrobial alternative strategies against BRD. This study aimed to screen and select candidate essential oils (EOs) for the development of an intranasal EO spray that can inhibit BRD pathogens and promote microbiota-mediated respiratory health.

Methods: The effects of selected EOs (ajowan, cinnamon leaf, citronella, grapefruit, fennel, and thyme) on a bovine nasopharyngeal microbiota culture were evaluated using 16S rRNA gene sequencing. The microbiota culture was enriched by incubating nasopharyngeal swabs obtained from finishing beef heifers in brain heart infusion broth with and without EOs (0.025%, v/v). These EOs were then also evaluated for their immunomodulatory effects on bovine turbinate (BT) cells by analyzing the concentrations of 15 cytokines and chemokines in cell culture after 24 h incubation. The crystal violet assay was done to assess the antibiofilm activity of EOs against Escherichia coli UMN026 strain. Finally, 15 EOs were screened for their antiviral activity against the bovine viral diarrhea virus 1 (BVDV-1) using BT cells and a fluorescence-based method.

Results: Ajowan, fennel, and thyme resulted in a moderate reduction of overall nasopharyngeal microbiota growth with significant alterations of both alpha and beta diversity, and the relative abundance of predominant bacterial families (e.g., increasing Enterobacteriaceae and decreasing Moraxellaceae) compared to the control (p < 0.05). Co-incubation of BT cells with selected EOs resulted in minimal alterations in cytokine and chemokine levels (p > 0.05). Ajowan, thyme, fennel, and cinnamon leaf exhibited antibiofilm activity at concentrations of 0.025 and 0.05%. Reduction of BVDV-1 replication in BT cells was observed with thyme (strong), and ajowan and citronella (moderate) at 0.0125% concentration.

Discussion: Accordingly, ajowan, thyme, fennel, cinnamon leaf, and citronella EOs were selected for further development as an intranasal EO spray to prevent and control of BRD pathogens in feedlot cattle.

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1 citations