Effects of in feed removal of antimicrobials in comparison to other prophylactic alternatives in growing and finishing pigs / [Efeitos na remoção de antimicrobianos na ração em comparação a alternativas profiláticas em suínos nas fases de crescimento e de terminação]

The utilization of antimicrobials in animal production, causes selection of resistant bacteria. The objective of this study was to compare the utilization of alternatives in association with preventive antibiotic therapy in swine feed during the growing and finishing phases. 1,045 animals were used from 60 to 190 days of age and were subjected to six treatments with 16 repetitions as follows: 1) antibiotic free; 2) antibiotics; 3) prebiotic; 4) probiotic; 5) essential oils; and 6) organic acid. Animals were weighted, and clinical history was recorded including mortality and diarrhea. At the abattoir, pneumonia index and gastric ulcers were investigated. The cost for each treatment was discussed. No difference between treatments were observed (P>0.05) regarding feed conversion rate (2.64±0.03), overall average weight gain (107.06±0.9kg), average daily weight gain (856.49±7.7g) and carcass weight (92.4±0.7kg). The application injectable drugs in animals presenting clinical symptoms, represented US$ 0.56/intervention, without difference between the treatments (P>0.05). Furthermore, independently of the treatment, high frequency of pneumonia was observed (>0.90). No difference for the degree of gastric ulcer nor feces consistency were observed (P>0.05). The utilization of antibiotic therapy and alternatives to antibiotics in feed did not produce benefits to the production indices and sanitary performances of the animals.(AU)

A utilização de antimicrobianos na produção animal provoca seleção de bactérias resistentes. O objetivo do estudo foi comparar a utilização de alternativas associadas à antibioticoterapia preventiva na alimentação de suínos nas fases de recria e de terminação. Foram utilizados 1.045 animais de 60 a 190 dias de idade, submetidos a seis tratamentos com 16 repetições, como segue: 1) sem antibióticos; 2) com antibióticos; 3) prebióticos; 4) probióticos; 5) óleos essenciais; e 6) ácidos orgânicos. Os animais foram pesados, e a história clínica foi registrada, incluindo mortalidade e diarreia. No abatedouro, foram investigados índices de pneumonia e úlceras gástricas. O custo de cada tratamento foi discutido. Não houve diferença entre os tratamentos (P>0,05) em relação à taxa de conversão alimentar (2,64 ± 0,03), ao ganho de peso médio geral (107,06 ± 0,9kg), ao ganho de peso médio diário (856,49 ± 7,7g) e ao peso de carcaça (92,4 ± 0,7kg). A aplicação de medicamentos injetáveis em animais com quadro clínico representou US$ 0,56/intervenção, sem diferença entre os tratamentos (P>0,05). Além disso, independentemente do tratamento, foi observada alta frequência de pneumonia (>0,90). Não foi observada diferença para o grau de úlcera gástrica nem na consistência das fezes (P>0,05). A utilização de antibioticoterapia e de alternativas aos antibióticos na ração não trouxe benefícios aos desempenhos zootécnico e sanitário dos animais.(AU)

Virulence-associated genes, antimicrobial resistance and molecular typing of Salmonella Typhimurium strains isolated from swine from 2000 to 2012 in Brazil.

AIMS: The aims of this study were to assess the pathogenic potential, antimicrobial resistance and genotypic diversity of Salmonella Typhimurium strains isolated in Brazil from swine (22) and the surrounding swine environment (5) from 2000 to 2012 and compare them to the profiles of 43 human strains isolated from 1983 to 2010, which had been previously studied. METHODS AND RESULTS: The presence of 12 SPI-1, SPI-2 and plasmid genes was assessed by PCR, the antimicrobial susceptibility to 13 antimicrobials was determined by the disc diffusion assay and genotyping was performed using pulsed-field gel electrophoresis (PFGE), multiple-locus variable-number of tandem repeats analysis (MLVA) and ERIC-PCR. More than 77·8% of the swine strains carried 10 or more of the virulence markers. Ten (37%) strains isolated from swine were multi-drug resistant (MDR). All the molecular typing techniques grouped the strains in two main clusters. Some strains isolated from swine and humans were allocated together in the PFGE-B2, MLVA-A1, MLVA-B and ERIC-A1 clusters. CONCLUSIONS: The genotyping results suggest that some strains isolated from swine and humans may descend from a common subtype and may indicate a possible risk of MDR S. Typhimurium with high frequency of virulence genes isolated from swine to contaminate humans in Brazil. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided new information about the pathogenic potential, antimicrobial resistance and genotypic diversity of S. Typhimurium isolates from swine origin in Brazil, the fourth largest producer of pigs worldwide.

Utility of specific biomarkers to assess safety of swine manure for biofertilizing purposes.

Swine production is an important economic activity in Brazil, and there is interest in the development of clean production mechanisms to support sustainable agro-industrial activities. The biomass derived from swine manure has good potential to be used as a biofertilizer due to its high nutrient concentration. However, the land application of manure should be based on safety parameters such as the presence of pathogens that can potentially infect animals and people. This study was designed to assess the presence of porcine circovirus-2 (PCV2), porcine adenovirus (PAdV), rotavirus-A (RV-A) and Salmonella spp. in liquid manure, as well the infectivity of two genotypes of circovirus-2 (PCV2a and PCV2b) present in liquid manure. Three swine farms were evaluated: 1) a nursery production farm (manure analyzed before and after anaerobic biodigestion), 2) a grow-finish production farm (analyzed before and after anaerobic biodigestion), and 3) a second grow-finish production farm (raw manure-affluent). PCV2, PAdV and RV-A were present before and after anaerobic biodigestion (either affluent or effluent) at all farms. Salmonella spp. were detected at farm 1 (affluent and effluent) and farm 3 (raw manure-affluent) but not farm 2 (affluent and effluent). When the ability of the anaerobic biodigestion process to reduce viral concentration was evaluated, no significant reduction was observed (P>0.05). Both the PCV2a and PCV2b genotypes were detected, suggesting viral co-infection in swine production. The results revealed infectious PCV2 even after anaerobic biodigestion treatment. The presence of Salmonella spp. and enteric viruses, especially infectious PCV2, in the final effluent from the anaerobic biodigester system suggests that the process is inefficient for pathogen inactivation. Due to the prevalence and infectivity of PCV2 and considering the successful use of molecular methods coupled to cell culture for detecting infectious PCV2, we suggest that this virus can be used as a bioindicator in swine manure treatment systems to check the efficiency of pathogen inactivation and ensure the production of safe biofertilizers from swine manure.

Polynucleotide phosphorylase (PNPase) is required for Salmonella enterica serovar Typhimurium colonization in swine.

The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA processing and degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for survival in an ex vivo swine stomach content assay. In the current study, attenuation and colonization potential of a S. Typhimurium pnp mutant in the porcine host was evaluated. Following intranasal inoculation with 10(9) cfu of either the wild-type S. Typhimurium χ4232 strain or an isogenic derivative lacking the pnp gene (n = 5/group), a significant increase (p < 0.05) in rectal temperature (fever) was observed in the pigs inoculated with wild-type S. Typhimurium compared to the pigs inoculated with the pnp mutant. Fecal shedding of the pnp mutant was significantly reduced during the 7-day study compared to the wild-type strain (p < 0.001). Tissue colonization was also significantly reduced in the pigs inoculated with the pnp mutant compared to the parental strain, including the tonsils, ileocecal lymph nodes, Peyer's Patch region of the ileum, cecum and contents of the cecum (p < 0.05). The data indicate that the pnp gene is required for S. Typhimurium virulence and gastrointestinal colonization of the natural swine host.

Performance of two swine manure treatment systems on chemical composition and on the reduction of pathogens.

Swine effluents must be correctly handled to avoid negative environmental impacts. In this study, the profiles of two swine manure treatment systems were evaluated: a solid-liquid separation step, followed by an anaerobic reactor, and an aerobic step (System 1); and a biodigester followed by serial lagoons (System 2). Both systems were described by the assessment of chemical, bacterial and viral parameters. The results showed that in System 1, there was reduction of chemicals (COD, phosphorus, total Kjeldhal nitrogen - TKN - and NH(3)), total coliforms and Escherichia coli; however, the same reduction was not observed for Salmonella sp. Viral particles were significantly reduced but not totally eliminated from the effluent. In System 2, there was a reduction of chemicals, bacteria and viruses with no detection of Salmonella sp., circovirus, parvovirus, and torque teno virus in the effluent. The chemical results indicate that the treated effluent can be reused for cleaning swine facilities. However, the microbiological results show a need of additional treatment to achieve a complete inactivation for cases when direct contact with animals is required.

Effect of organic acids and mannanoligosaccharide on excretion of Salmonella typhimurium in experimentally infected growing pigs.

The effect of organic acids and mannanoligosaccharide addition to the diet was assessed in pigs orally inoculated with Salmonella typhimurium. Forty-six growers were distributed among four treatments: Basal Diet (BD); BD+encapsulated organic acids; BD+free organic acids; BD+mannanoligosaccharide. Seroconversion was monitored, and feces and tissue samples were tested for Salmonella isolation. No treatment prevented the carrier state, but a tendency of lower fecal excretion was observed in the group treated with mannanoligosaccharide.

Use of an avirulent live Salmonella Choleraesuis vaccine to reduce the prevalence of Salmonella carrier pigs at slaughter.

This study evaluated the use of an avirulent live Salmonella Choleraesuis vaccine to reduce the seroprevalence and number of Salmonella carrier pigs at slaughter. Seven batches of 500 pigs were included in each of the two study groups: the vaccinated group (VG) that was orally vaccinated and the control group (CG) that received a placebo on the first day of life. The groups were managed in a three-site system and followed up from birth to slaughter. Blood samples (n=378) were collected from each VG and CG to monitor the on-farm seroprevalence in both groups. Mesenteric lymph nodes and blood from animals (n=390) belonging to each group were collected at slaughter. At the first day of life, the seroprevalence in control batches ranged from 77.9 to 96.3 per cent, while in vaccinated batches, it ranged from 66.6 to 92.6 per cent. At weaning (21 days of age), the number of seropositives decreased in both groups (mean of 12 and 3.7 per cent for CG and VG, respectively). At slaughter, batches of VG had a significantly (P<0.0001) lower seroprevalence (46.6±5 per cent) and isolation of Salmonella from lymph nodes (33.1±5 per cent) compared with CG batches (79.7±4 per cent and 59.5±5 per cent, respectively). The results indicate that administration of a Salmonella choleraesuis-attenuated vaccine on the first day of life decreases Salmonella isolation and seroprevalence in pigs at slaughter.

Detection of Mycoplasma hyopneumoniae by polymerase chain reaction in swine presenting respiratory problems / Detecção do mycoplasma hyopneumoniae pela reação em cadeia da polimerase em suínos apresentando problemas respiratórios

Since Mycoplasma hyopneumoniae isolation in appropriate media is a difficult task and impractical for daily routine diagnostics, Nested-PCR (N-PCR) techniques are currently used to improve the direct diagnostic sensitivity of Swine Enzootic Pneumonia. In a first experiment, this paper describes a N-PCR technique optimization based on three variables: different sampling sites, sample transport media, and DNA extraction methods, using eight pigs. Based on the optimization results, a second experiment was conducted for testing validity using 40 animals. In conclusion, the obtained results of the N-PCR optimization and validation allow us to recommend this test as a routine monitoring diagnostic method for Mycoplasma hyopneumoniae infection in swine herds.

A Nested-PCR (N-PCR) tem como objetivo melhorar a sensibilidade do diagnóstico direto da Pneumonia Enzoótica Suína, pois o isolamento do Mycoplasma hyopneumoniae é trabalhoso tornando-se inviável na rotina. Neste trabalho, foi realizado um projeto piloto para a otimização da técnica de N-PCR, utilizando três variáveis: tipo de amostra biológica, meio de transporte da amostra e método de extração do DNA, utilizando oito animais. Os resultados obtidos foram empregados no segundo experimento para a validação do teste utilizando 40 animais. Os resultados obtidos, pela otimização da N-PCR, neste trabalho, permite sugerir esta prova como método de diagnóstico de rotina no monitoramento das infecções por Mycoplasma hyopneumoniae em granjas de suínos.

Padronização de três ELISAs polivalentes com lipopolissacarídeos de cadeia longa dos sorotipos 1 e 5, 2, 3 e 7 ou 10 e 12 de Actinobacillus pleuropneumoniae / Standardization of three polyvalent ELISA based on long chain lipopolysaccharides of serotypes 1 and 5, 2, 3 and 7, or 10 and 12 of Actinobacillus pleuropneumoniae

Três ELISAs polivalentes baseados em lipopolissacarídeos de cadeia longa (LPS-CL) foram estabelecidos para detectar anticorpos para todos os sorotipos prevalentes de Actinobacillus pleuropneumoniae. Foram testadas amostras provenientes do banco de soros de suínos experimentalmente inoculados com todos os sorotipos de A. pleuropneumoniae. Os ELISAs foram sensíveis à detecção de anticorpos contra todos os LPS-CL. Foram observadas reações cruzadas no ELISA polivalente produzido com os sorotipos 1 e 5, com anti-soros específicos para os sorotipos 9 e 11, pois os sorotipos 1, 9 e 11 apresentaram antígenos somáticos comuns. No polivalente com os sorotipos 2, 3 e 7, observaram-se reações com anti-soros dos sorotipos 4, 6 e 8, devido à presença de antígenos somáticos entre os sorotipos 3, 6 e 8 e entre os sorotipos 4 e 7. Amostras de soros de animais infectados com Mycoplasma hyopneumoniae, Mycoplasma flocculare e Haemophilus parasuis, agentes que acometem o sistema respiratório dos suínos, não apresentaram reações cruzadas com os antígenos baseados em LPS-CL.

Three polyvalent ELISA based on long chain lipopolysaccharides (LC-LPS) were established to detect all prevalent serotypes of Actinobacillus pleuropneumoniae. Samples from a serum bank of experimentally inoculated animals with all serotypes of A. pleuropneumoniae were tested. Antibodies specific to LC-LPS of each serotype were detected. Cross-reactions were observed in the polyvalent ELISA produced with serotypes 1 and 5, with specific antisera to serotypes 9 and 11 due to common somatic antigens presence in serotypes 1, 9, and 11. In the polyvalent with serotypes 2, 3 and 7 reactions were observed with antisera of serotypes 4, 6, and 8, due to the presence of somatic antigens in serotypes 3, 6, and 8 and serotypes 4 and 7. Experimentally infected animals with respiratory agents of swine Mycoplasma hyopneumoniae, Mycoplasma flocculare, and Haemophilus parasuis did not present cross-reactions with the antigens based on LC-LPS.

Detection of Mycoplasma hyopneumoniae by polymerase chain reaction in swine presenting respiratory problems.

Since Mycoplasma hyopneumoniae isolation in appropriate media is a difficult task and impractical for daily routine diagnostics, Nested-PCR (N-PCR) techniques are currently used to improve the direct diagnostic sensitivity of Swine Enzootic Pneumonia. In a first experiment, this paper describes a N-PCR technique optimization based on three variables: different sampling sites, sample transport media, and DNA extraction methods, using eight pigs. Based on the optimization results, a second experiment was conducted for testing validity using 40 animals. In conclusion, the obtained results of the N-PCR optimization and validation allow us to recommend this test as a routine monitoring diagnostic method for Mycoplasma hyopneumoniae infection in swine herds.

Infecção por Salmonella enterica em suínos criados em um sistema integrado de produção do sul do Brasil / Salmonella infection in pigs raised in a multiple-site swine production system from southern Brazil

Avaliou-se a difusão da infecção em um rebanho com prévio isolamento de Salmonella sp, em que leitões, individualmente identificados, foram amostrados para excreção fecal de Salmonella sp e sorologia do nascimento ao abate. Da mesma forma, amostras de ração e suabes do ambiente foram coletados durante o estudo para pesquisa de Salmonella sp A pesquisa de anticorpos foi realizada pela utilização de ELISA-LPS de Salmonella Typhimurium. Os leitões foram negativos na análise bacteriológica e na sorologia até a fase de creche, tornando-se positivos para Salmonella sp no início da terminação. Nessa amostragem, 28,6 por cento dos animais foram soropositivos e 75 por cento estavam excretando Salmonella sp nas fezes. Ao abate, a percentagem de animais soropositivos (76,9 por cento) aumentou, enquanto o isolamento de Salmonella sp ocorreu em 19,2 por cento dos suínos. Foi isolada Salmonella sp de duas das 26 amostras de ração. A contaminação do ambiente da terminação ocorreu apenas após o alojamento dos animais. Concluiu-se que a terminação foi o ponto crítico de contaminação desse lote, sendo a ração uma fonte de contaminação.

Salmonella diffusion in a swine production system, previously identified as Salmonella-positive, was evaluated. A cohort of pigs was followed from farrowing to slaughtering. Samples of feces, intestinal content, mesenteric lymph nodes and blood were taken from the animals throughout the study. In addition, feed samples and environmental swabs were done for the isolation of Salmonella sp. Serum was submitted to a Salmonella Typhimurium LPS-ELISA. Piglets were negative in bacteriological and serological tests until the nursery phase, but became Salmonella positive in the early finishing. On this phase, 28.6 percent of finishers were seropositive and 75 percent were shedding Salmonella in feces. At slaughtering, the seropositivity (76.9 percent) was higher than in the early finishing, but Salmonella was isolated only from 19.2 percent of the sampled pigs. Two out of 26 feed samples were Salmonella positive. Contamination of the finishing site environment was detected only when the animals were housed. It was concluded that the termination phase was critical for the contamination of this cohort of pigs, being the feed a source of contamination.

Comparaçäo de métodos de isolamento de bactérias NAD-dependentes do trato respiratório superior de suínos sadios / Methods to isolate NAD-dependent bacteria from the upper respiratory tract of health pigs

Secreçöes nasais, tonsilares e tecido tonsilar foram coletados de 67 leitöes de 9 a 15 semanas de idade, provenientes de três rebanhos positivos para Actinobacillus pleuropneumoniae (App), e de 50 leitöes provenientes de dois rebanhos, negativos. Foram classificados como positivos aqueles rebanhos com isolamento prévio de sorotipos 3, 5 e 7 e rebanhos negativos aqueles submetidos a controle veterinário, sem notificaçäo de sintomas clínicos, lesöes de pleuropneumonia suína e sem isolamento do agente. O material coletado foi submetido a três diferentes métodos de cultivo: 1- semeadura direta em meio de cultivo sólido seletivo; 2- diluiçäo em caldo seletivo seguido de subsemeadura em meio de cultivo sólido seletivo; 3- diluiçäo em caldo seletivo seguido de subsemeadura em ágar sangue. Entre as amostras NAD-dependentes recuperadas 86 foram classificadas como App, 13 como grupo minor e 21 como grupo taxon (C, D, E e F). Dos rebanhos positivos foram recuperadas quatro amostras de App (sorotipos 3, 7 e 12) e 51 näo sorotipificáveis. Dos rebanhos negativos foram recuperadas 31 amostras de App näo sorotipificáveis, indicando que o App faz parte da flora normal do trato respiratório superior dos suínos. O melhor método de isolamento de amostras NAD-dependentes de leitöes portadores foi da biópsia de tecido tonsilar semeado diretamente em meio sólido seletivo (PPLO ágar adicionado de 2 mica grama de cristal violeta, 10 mica grama NAD, 1 mica grama de lincomicina, 1,4 mica grama de bacitracina por ml)

Utilizaçäo de um teste de ELISA polivalente para detecçäo de anticorpos contra Actinobacillus pleuropneumoniae (App) / Utilization of a polyvalent ELISA test for detection antibodies against of Actinobacillus pleuropneumoniae

Um teste de ELISA polivalente baseado em lipopolissacarídeos de cadeia longa (LPS - CL) de Actinobacillus pleuropneumoniae (App) sorotipos 3, 5 e 7 foi avaliado testando-se amostras do soro de leitöes e matrizes provenientes de 10 rebanhos positivos e de 10 rebanhos negativos. Foram classificados como positivos aqueles rebanhos com isolamento prévio do App sorotipos 3, 5 ou 7 e rebanhos negativos aqueles submetidos ao controle veterinário, sem notificaçäo de sintomas clínicos, sem lesöes de pleuropneumonia suína e sem isolamento do agente. Todos os rebanhos positivos apresentaram sorologia positiva e as matrizes apresentaram maior número de soroconversores (P<0,05) do que os leitöes. Entre os rebanhos negativos quatro apresentaram sorologia negativa, cinco sorologia positiva com valores preditivos altos (96 a 99 por cento) e um com valor preditivo considerado baixo (56 por cento). O teste apresentou 100 por cento de sensibilidade e aparentemente baixa especificidade, porém, como detectou os sorotipos prevalentes no Brasil e sorotipos que possuem LPS - CL homólogos (3, 4, 5, 6, 7 e 8), ele é aplicável somente como teste de triagem