scholarly journals The use of tylvalosin (Aivlosin®) in the successful elimination of swine dysentery on a farrow-to-finish herd

2012 ◽  
Vol 81 (4) ◽  
pp. 205-210
Author(s):  
P. Vyt ◽  
L. Vandepitte ◽  
A. Dereu ◽  
M. Roozen
Keyword(s):  
Management Practices ◽  
Clinical Symptoms ◽  
Monitoring Program ◽  
Single Site ◽  
Economic Losses ◽  
Antimicrobial Use ◽  
Rodent Control ◽  
Feed Conversion ◽  
Swine Industry ◽  
Swine Dysentery

Swine dysentery causes severe economic losses in swine industry. Eliminating the disease at farm level can become problematic when resistance of the causative agent, Brachyspira hyodysenteriae, against pleuromutilins is reported. In this study, the use of tylvalosin (Aivlosin®) in eliminating the disease in a single-site, farrow-to-finish herd was evaluated. In addition, productivity parameters and antimicrobial use were compared prior to and after implementing the elimination protocol. On a mixed farm of 200 sows and 1500 finishers with a history of chronic dysentery, the B. hyodysenteriae isolate was resistant to pleuromutilins but had a low minimum inhibitory concentration for tylvalosin (2 μg/ml). Combined with a strict program for rodent control and hygiene, sows were treated with tylvalosin at a dose of 4.25 mg/kg BW daily for four weeks. The sows were washed one week after the start of the treatment before entering a clean stable. Piglets born from sows that had received this treatment, were considered free from dysentery and were kept separated from infected, untreated animals on the farm. A monitoring program with monthly sampling of sows and fatteners was installed to evaluate the absence of B. hyodysenteriae on the farm. After treatment, the clinical symptoms in the treated sows disappeared and remained absent in the offspring born after the procedure. Fecal samples examined by PCR remained negative for the whole testing period (14 months after the end of the treatment) and no clinical outbreaks were reported afterwards. The feed conversion ratio improved by 12%, the mortality rate with 37% and the antimicrobial use decreased by 71.5%. We conclude that the elimination of swine dysentery on a single-site, farrow-to-finish herd is possible using tylvalosin (AivlosinR) combined with strict hygiene and rodent control. The improvements of the technical parameters in this study are not only the result of the elimination of B. hyodysenteriae, but also changes in management practices influenced these parameters.

scholarly journals Meclizine Inhibits Pseudorabies Virus Replication by Interfering With Virus Entry and Release

2021 ◽  
Vol 12 ◽  
Author(s):  
Panrao Liu ◽  
Danhe Hu ◽  
Lili Yuan ◽  
Zhengmin Lian ◽  
Xiaohui Yao ◽  
...  
Keyword(s):  
Viral Entry ◽  
Pseudorabies Virus ◽  
Molecular Mechanisms ◽  
Clinical Symptoms ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Economic Losses ◽  
Swine Industry ◽  
Viral Attachment ◽  
Viral Loads

Pseudorabies virus (PRV) is a pathogen that causes substantial economic losses to the swine industry. With the emergence and widespread of PRV variants since 2011 in China, current commercial vaccines cannot provide complete protection against PRV infection. Therefore, antiviral drugs may work as an alternative way to control and prevent PRV. In this study, the inhibitory effects and underlying molecular mechanisms of meclizine against PRV were studied. Meclizine displayed a significant inhibitory effect against PRV when it was added before, simultaneously with, or after virus infection. The inhibitory effect of meclizine occurred during viral entry and cell-to-cell spreading but not at viral attachment into PK-15 cells. Meclizine also inhibited viral particle release at the late stage of infection. The antiviral effect of meclizine was tested in mice, and the results showed that meclizine reduced the severity of clinical symptoms and the viral loads in tissues, and delayed the death, after PRV challenge. The above results indicated that meclizine had an inhibitory effect on PRV. Our findings will contribute to the development of potential therapeutic drugs against PRV infection.

scholarly journals Occurrence of Mycoplasma hyopneumoniae in slaughter pigs from Southern Brazil

2019 ◽  
Vol 56 (1) ◽  
pp. e150072
Author(s):  
Violetta Dias Pacce ◽  
Natasha Rodrigues de Oliveira ◽  
Sérgio Jorge ◽  
Odir Antônio Dellagostin
Keyword(s):  
Nested Pcr ◽  
Mycoplasma Hyopneumoniae ◽  
Economic Losses ◽  
Limited Information ◽  
Southern Brazil ◽  
Feed Conversion ◽  
Swine Industry ◽  
Lung Lesions ◽  
Slaughter Pigs ◽  
Gross Lesions

Mycoplasma hyopneumoniae is the causative agent of enzootic pneumonia (EP), a disease that is highly prevalent and globally distributed, causing significant economic losses to the swine industry. Disease progression is characterized by reduced feed conversion and the development of lung lesions. Considering the limited information about the epidemiology of EP in Southern Brazil, the main objective of this study was to determine the occurrence of M. hyopneumoniae in swine lung samples and to evaluate the scores of lung lesions caused by local strains. A total of 120 samples was randomly collected and processed. DNA was extracted from lung tissue to perform nested-PCR and lungs were inspected to evaluate the presence of the pneumonia-like gross lesions of M. hyopneumoniae. The results showed 95.8% positive samples, while the lung lesion score analysis showed suggestive lesions in 60% of samples. The detection of positive samples in nested-PCR was associated with the presence of pneumonia-like gross lesions (P < 0.01). The results demonstrate a high occurrence of EP in slaughter pigs from southern Brazil.

scholarly journals ASFV bearing an I226R gene-deletion elicits a robust immunity in pigs to African swine fever

2021 ◽  
Author(s):  
Yanyan Zhang ◽  
Junnan Ke ◽  
Jingyuan Zhang ◽  
Jinjin Yang ◽  
Huixian Yue ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Clinical Symptoms ◽  
African Swine Fever Virus ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Parental Virus ◽  
Economic Losses ◽  
Egfp Expression ◽  
Post Inoculation ◽  
Swine Industry

African swine fever (ASF) is a severe hemorrhagic infectious disease in pigs caused by the African swine fever virus (ASFV), leading to devastating economic losses in the epidemic regions. Its control currently depends on thorough culling and clearance of the diseased and the surrounding suspected pigs. ASF vaccine has been extensively explored for years worldwide, especially in hog-intensive areas where it is highly desired, but it is still unavailable due to numerous reasons. Herein, we reported another ASF vaccine candidate named SY18ΔI226R bearing a deletion of the I226R gene in replacement of an eGFP expression cassette at the right end of the viral genome. This deletion results in complete loss of virulence of SY18 as the gene-deleted strain does not cause any clinical symptoms in all pigs inoculated with either a dosage of 10 4.0 TCID 50 or 10 7.0 TCID 50 . An apparent viremia with the gradual decline was monitored, while the virus shedding was only occasionally detected in oral- or anal swabs. ASFV specific antibody appeared at 9 days post-inoculation. After intramuscular challenge with its parental strain ASFV SY18 on 21 days post inoculation, all the challenged pigs survived without obvious febrile or abnormal clinical signs. No viral DNA could be detected on the dissection of any tissue when viremia disappeared. These indicated that SY18ΔI226R is safe in swine and elicits a robust immunity to the virulent ASFV infection. IMPORTANCE: Outbreaks of African swine fever have resulted in devastating losses to the swine industry worldwide, but there is currently no commercial vaccine available. Although several vaccine candidates have been reported, none has been approved for use due to several reasons, especially the ones concerning bio-safety. Here, we identified a new undescribed functional gene, I226R. When deleted from the ASFV genome, the virus completely loses its virulence in the swine. Importantly, pigs infected with this gene-deleted virus were resistant to infection by an intramuscular challenge of 10 2.5 or 10 4.0 TCID 50 of its virulent parental virus. Furthermore, rarely the nucleic acid of the gene-deleted virus and its virulent parental virus was detected from oral- or anal swabs. Viruses could not be detected in any tissues after necropsy when viremia became negative, indicating that robust immunity was achieved. Therefore, SY18ΔI226R is a novel, ideal and efficacious vaccine candidate for genotype II ASF.

scholarly journals Alternatives to Fight Against Coccidiosis: A Review

2017 ◽  
Vol 34 ◽  
pp. 152-167
Author(s):  
K.P. Acharya ◽  
N. Acharya
Keyword(s):  
Management Practices ◽  
Chemical Compounds ◽  
Residual Effects ◽  
Farm Animals ◽  
Economic Losses ◽  
Natural Food ◽  
Regulatory Change ◽  
Feed Conversion ◽  
Consumer Awareness ◽  
Phase Out

Coccidiosis is one of the most important parasitic diseases of poultry with economic losses. The loss is mainly due to the poor feed conversion and increased mortality. Nowadays, farmers rely heavily on prophylactic and therapeutic use of chemical compounds for the management of coccidiosis. The conventional anti-coccidials, however, are associated with residual effects and increased resistance. Similarly, increasing consumer awareness and their pressure for natural food has increased governmental pressure basically. Because of regulatory change, there is increasing pressure to phase out the chemical anticoccidials in diet of farm animals. Moreover, there are renewed management practices as alternatives that are safe, little/no residual effects, and economical. Non-conventional compounds such as Mannan-oligosaccharides (MOS), organic acids, phyto-chemicals, probiotics and essentials oils have shown encouraging result against coccidian growth in intestinal mucosa of chicken and turkey. But, comprehensive studies on chemical structure, modes of action and residual effects is needed to unravel their applicability and effectiveness in the field conditions.

scholarly journals Recombinant pseudorabies virus with gI/gE deletion generated by overlapping polymerase chain reaction and homologous recombination technology induces protection against the PRV variant PRV-GD2013

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Wenhui Li ◽  
Dijing Zhuang ◽  
Hong Li ◽  
Mengpo Zhao ◽  
Erpeng Zhu ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Vaccine Strain ◽  
Recombinant Virus ◽  
Pseudorabies Virus ◽  
Clinical Symptoms ◽  
Growth Curves ◽  
Economic Losses ◽  
Plaque Morphology ◽  
Swine Industry ◽  
Antigenic Variant

Abstract Background Since 2011, numerous highly virulent and antigenic variant viral strains have been reported in pigs that were vaccinated against the swine pseudorabies virus. These infections have led to substantial economic losses in the Chinese swine industry. Results This study, constructed a novel recombinant vaccine strain with gI/gE deletion (PRV-GD2013-ΔgI/gE) by overlapping PCR and homologous recombination technology. The growth curves and plaque morphology of the recombinant virus were similar to those of the parental strain. However, PRV-GD2013-ΔgI/gE infection was significantly attenuated in mice compared with that of PRV-GD2013. Two-week-old piglets had normal rectal temperatures and displayed no clinical symptoms after being inoculated with 105 TCID50 PRV-GD2013-ΔgI/gE, indicating that the recombinant virus was avirulent in piglets. Piglets were immunized with different doses of PRV-GD2013-ΔgI/gE, or a single dose of Bartha-K61 or DMEM, and infected with PRV-GD2013 at 14 days post-vaccination. Piglets given high doses of PRV-GD2013-ΔgI/gE showed no obvious clinical symptoms, and their antibody levels were higher than those of other groups, indicating that the piglets were completely protected from PRV-GD2013. Conclusions The PRV-GD2013-ΔgI/gE vaccine strain could be effective for immunizing Chinese swine herds against the pseudorabies virus (PRV) strain.

Swine influenza vaccines: current status and future perspectives

2010 ◽  
Vol 11 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Wenjun Ma ◽  
Jürgen A. Richt
Keyword(s):  
Influenza A ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Current Status ◽  
Economic Losses ◽  
Influenza A Viruses ◽  
Swine Industry ◽  
Effective Strategies ◽  
Swine Disease ◽  
And Control

AbstractSwine influenza is an important contagious disease in pigs caused by influenza A viruses. Although only three subtypes of influenza A viruses, H1N1, H1N2 and H3N2, predominantly infect pigs worldwide, it is still a big challenge for vaccine manufacturers to produce efficacious vaccines for the prevention and control of swine influenza. Swine influenza viruses not only cause significant economic losses for the swine industry, but are also important zoonotic pathogens. Vaccination is still one of the most important and effective strategies to prevent and control influenza for both the animal and human population. In this review, we will discuss the current status of swine influenza worldwide as well as current and future options to control this economically important swine disease.

scholarly journals The Function of the PRRSV–Host Interactions and Their Effects on Viral Replication and Propagation in Antiviral Strategies

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 364
Author(s):  
Jun Ma ◽  
Lulu Ma ◽  
Meiting Yang ◽  
Wei Wu ◽  
Wenhai Feng ◽  
...  
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Immune Escape ◽  
Rna Virus ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Swine Industry ◽  
Live Virus ◽  
Virus Challenge ◽  
Host Interactions

Porcine reproductive and respiratory syndrome virus (PRRSV) affects the global swine industry and causes disastrous economic losses each year. The genome of PRRSV is an enveloped single-stranded positive-sense RNA of approximately 15 kb. The PRRSV replicates primarily in alveolar macrophages of pig lungs and lymphatic organs and causes reproductive problems in sows and respiratory symptoms in piglets. To date, studies on how PRRSV survives in the host, the host immune response against viral infections, and pathogenesis, have been reported. PRRSV vaccines have been developed, including inactive virus, modified live virus, attenuated live vaccine, DNA vaccine, and immune adjuvant vaccines. However, there are certain problems with the durability and effectiveness of the licensed vaccines. Moreover, the high variability and fast-evolving populations of this RNA virus challenge the design of PRRSV vaccines, and thus effective vaccines against PRRSV have not been developed successfully. As is well known, viruses interact with the host to escape the host’s immune response and then replicate and propagate in the host, which is the key to virus survival. Here, we review the complex network and the mechanism of PRRSV–host interactions in the processes of virus infection. It is critical to develop novel antiviral strategies against PRRSV by studying these host–virus interactions and structures to better understand the molecular mechanisms of PRRSV immune escape.

Differential effects of early-life and post-weaning galactooligosaccharides intervention on colonic bacterial composition and function in weaning piglets

2021 ◽  
Author(s):  
Shiyi Tian ◽  
Jue Wang ◽  
Jing Wang ◽  
Weiyun Zhu
Keyword(s):  
Gene Expression ◽  
Early Life ◽  
Short Chain Fatty Acids ◽  
Combined Effect ◽  
Economic Losses ◽  
Swine Industry ◽  
Bacterial Composition ◽  
Colonic Microbiota ◽  
Α Diversity ◽  
Weaning Piglets

Recently, we have proved that the early-life galactooligosaccharides (GOS) intervention could improve the colonic function by altering the bacterial composition in the suckling piglets. However, whether the early-life GOS (ELG) intervention could have a long influence of the colonic microbiota, and the ELG and post-weaning GOS (PWG) combined intervention would have an interaction effect on maintaining colonic health in weaning piglets remain to be explored. Thus in this study, we illustrated the differential effect of ELG and PWG intervention on colonic microbiota and colonic function of weaning piglets. Our results showed that both the ELG and PWG intervention decreased the diarrhea frequency of weaning piglets, while the PWG intervention increased colonic indexes. After 16S rRNA MiSeq sequencing of gut bacteria belonged to colonic niches (mucosa and digesta), the PWG increased the α-diversity of colonic mucosal bacteria was revealed. In addition, we found both the ELG and PWG intervention enriched the abundance of short chain fatty acids (SCFAs) producer in different colonic niches and increased total SCFAs concentrations in colonic digesta. These changes selectively modulated the mRNA expression of pattern recognition receptors and barrier proteins in the colonic mucosa. Of note, the combined effect of ELG and PWG effectively enhanced colonic SCFAs producer enrichment and up-regulated the butyrate concentration. Meanwhile, the gene expression of MyD88-NFκB signaling and the pro-inflammatory cytokines contents were markedly reduced under the combined effect of ELG and PWG. Importance Reducing the disorders of gut ecosystem is an effective way to relieve weaning stresses of piglets and save economic losses in the modern swine industry. To this end, prebiotics were often added in diet during the weaning transition. In present study, we demonstrated that the ELG and PWG intervention had shown different effects on the bacterial composition of different colonic niches and colonic function in the weaning piglets. Especially under the combined effect of ELG and PWG intervention, the gene expression of MyD88-NFκB signaling and the contents of pro-inflammation cytokines decreased with the increasing concentration of butyrate, which is one of the important microbial metabolites in the colon of weaning piglets. These findings further provided new insights into nutritional interventions to alleviate intestinal ecosystem dysbiosis and gut dysfunction in the piglets during the weaning transition.

scholarly journals Prevalence, distribution and pattern of gastric lesions in slaughtered pigs in south-western Nigeria

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Oladipo O. Omotosho ◽  
Benjamin O. Emikpe ◽  
Olalekan T. Lasisi ◽  
Theophilus A. Jarikre
Keyword(s):  
Standard Technique ◽  
Gastric Ulcers ◽  
Economic Losses ◽  
Gastric Lesions ◽  
Swine Industry ◽  
Chi Square ◽  
Slaughter House ◽  
Gross Lesions ◽  
Frequency Counts ◽  
Slaughtered Pigs

Gastric lesions, especially ulceration, cause significant economic losses in the swine industry worldwide. The study was designed to assess its prevalence, distribution and pattern in pigs in south-western Nigeria. Slaughter house surveys were conducted on three government-established abattoirs in Lagos, Ogun and Oyo states. Stomachs from 480 pigs were assessed for gross lesions, which were graded using a modification of a standard technique. Tissues from different regions of the stomach were routinely stained to assess histopathologic changes. Data were presented as frequency counts and analysed using analysis of variance and chi-square technique. Significance was determined at p ≤ 0.05. Gastric lesions were encountered across the four regions of the stomach with a point prevalence of 57.29%. The prevalence of lesions in the non-glandular region was 32.9%, with severe hyperkeratosis (13.13%) being most frequently observed (p < 0.05). Erosions were significantly higher in the cardia (8.54%) (p < 0.05), followed by fundus (8.33%). Gastric ulcers were significantly higher in the fundus (19.58%) (p < 0.05). Scars of healed ulcers and lacerations were also observed in the fundus (5.42%) (p < 0.05). The gastric lesion distribution across the four regions of the stomach and the occurrence of ulceration in the fundus showed an unusual pattern, which is rarely reported in other parts of the world. The reason for these findings in pigs in Nigeria is not fully understood; therefore, further studies are required to identify and manage these factors for increased productivity, improved animal welfare and enhanced food security.Keywords: prevalence; gastric; lesions; fundic ulcers; pigs

scholarly journals Nitrogen and phosphorus flux from the production of Nile tilapia through the application of environmental indicators

2017 ◽  
Vol 78 (1) ◽  
pp. 25-31 ◽  
Author(s):  
J. A. S. Osti ◽  
M. A. B. Moraes ◽  
C. F. Carmo ◽  
C. T. J. Mercante
Keyword(s):  
Best Management Practices ◽  
Nile Tilapia ◽  
Management Practices ◽  
Environmental Indicators ◽  
Conversion Ratio ◽  
Feed Conversion Ratio ◽  
Phase Iii ◽  
Production Cycle ◽  
Fish Biomass ◽  
Feed Conversion

Abstract We aimed in this study utilize environmental indicators as a quantitative method to evaluate and discuss the nitrogen (TN) and phosphorus (TP) flux by a production stage grow-out (termination) of Nile tilapia (Oreochromis niloticus) in fishpond. The TN and TP load, the mass balance, the input of TN and TP via feed and the converted nutrients in fish biomass are the environmental indicators applied in this study. During the production cycle (128 days), the system exported 15,931 g TN and 4,189 g TP that were related to the amount of feed supplied (r Pearson = 0.8825 and r = 0.8523, respectively), corroborated by the feed conversion ratio (1.61:1). The indicators showed that 26% TN and 45% TP were reversed into fish biomass, 62% TN and 40% TP were retained in the fishpond, and 12% TN and 15% TP were exported via effluent. The largest contribution of nutrients generated by the system and exported via effluent was observed in phase III and IV. This result is supported by the feed conversion ratio 2.14 and 2.21:1 obtained at this phase, a fact explained by the amount of feed offered and the fish metabolism. Application of environmental indicators showed to be an efficient tool to quantify flux of TN and TP produced during the grow-out period of Nile tilapia and therefore, guide management practices more sustainable. Concerning the environmental sustainability of the activity the implementation of best management practices such as the better control of the feed amount offered would lead to a smaller loss of TN and TP to the water. Furthermore, the use of better quality feeds would allow greater nutrient assimilation efficiency.

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