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)

Genetic Similarities of Escherichia Coli Isolated from Different Substrates of the Broiler Production Chain

Brazil is the largest exporter of chicken meat and poultry farming is one of the most important productive segments, despite major losses due to the bacterium Escherichia coli, which is also a zoonotic microorganism. The objetive of this study was to isolate E. coli and to evaluate its transmissibility potential from the field to chicken meat using the Pulsed Field Gel Electrophoresis (PFGE) technique. Environmental samples (poultry litter, soil and water) were collected from broiler farms located in the South of Brazil where the majority of the Brazilian poultry production occurs. In addition, chicken meat (gizzard, heart, drumette and tulip) samples were collected from local supermarkets. As results, 47.36% of the samples were positives for E. coli. Furthermore, 10 pairs of clones of E. coli were found always in the same substrate (two water-water pairs; three soil-soil pairs and five meat-meat pairs) using PFGE. These findings suggest that certain strains of E. coli may have habitat preferences, making the transfer from one substrate type to another more difficult to occur. Moreover, since no clones were found between environmental samples and chicken meat, it is possible to imply a low risk of E. coli transmissibility throughout the chicken meat production chain.(AU)

Genetic Similarities of Escherichia Coli Isolated from Different Substrates of the Broiler Production Chain

Brazil is the largest exporter of chicken meat and poultry farming is one of the most important productive segments, despite major losses due to the bacterium Escherichia coli, which is also a zoonotic microorganism. The objetive of this study was to isolate E. coli and to evaluate its transmissibility potential from the field to chicken meat using the Pulsed Field Gel Electrophoresis (PFGE) technique. Environmental samples (poultry litter, soil and water) were collected from broiler farms located in the South of Brazil where the majority of the Brazilian poultry production occurs. In addition, chicken meat (gizzard, heart, drumette and tulip) samples were collected from local supermarkets. As results, 47.36% of the samples were positives for E. coli. Furthermore, 10 pairs of clones of E. coli were found always in the same substrate (two water-water pairs; three soil-soil pairs and five meat-meat pairs) using PFGE. These findings suggest that certain strains of E. coli may have habitat preferences, making the transfer from one substrate type to another more difficult to occur. Moreover, since no clones were found between environmental samples and chicken meat, it is possible to imply a low risk of E. coli transmissibility throughout the chicken meat production chain.

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.(AU)

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.(AU)

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.

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.

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% dos animais foram soropositivos e 75% estavam excretando Salmonella sp nas fezes. Ao abate, a percentagem de animais soropositivos (76,9%) aumentou, enquanto o isolamento de Salmonella sp ocorreu em 19,2% 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.(AU)

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% of finishers were seropositive and 75% were shedding Salmonella in feces. At slaughtering, the seropositivity (76.9%) was higher than in the early finishing, but Salmonella was isolated only from 19.2% 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.(AU)

Utilização de um teste de ELISA polivalente para detecção de anticorpos contra Actinobacillus pleuropneumoniae (App)

Sera from piglets and sows from 10 positive and 10 negative herds to Actinobacillus pleuropneumoniae (App) were submitted to a polyvalent ELISA test based on long chain lipopolysaccharides (LC-LPS) against sorotypes 3, 5 and 7. Positive herds were those in which a strain of serotype 3, 5 or 7 was isolated and negative those ones in which there were neither notification of clinical symptoms, nor lesions of swine pleuropneumoniae, nor App isolation and all the herds were under veterinary control. All positive herds contained animals that seroconverted and the frequency of sows serologically positive was significantly higher than that of positive piglets. Four negative herds were serologically negative, but five herds had sows considered positive with high positive predictive values (96 to 99%) and one herd had a positive predictive value of 56%. The polyvalent ELISA LC-LPS to App serotypes 3, 5 and 7 had 100 % of sensibility but apparently low specificity. The sensibility of the polyvalent test and its capability of detecting the prevalent Brazilian serotypes and those with shared LPS antigens (3, 4, 5, 6, 7 e 8) indicates that this test might be used only as a screening test.

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 leitões 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 notificação de sintomas clínicos, sem lesões 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 leitões. Entre os rebanhos negativos quatro apresentaram sorologia negativa, cinco sorologia positiva com valores preditivos altos (96 a 99%) e um com valor preditivo considerado baixo (56%). O teste apresentou 100% 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.

Comparação de métodos de isolamento de bactérias NAD-dependentes do trato respiratório superior de suínos sadios

Nasal and tonsil secretions and tonsil tissue were collected from 67 piglets (9-to-15 weeks old) from three positive herds and from 50 piglets from two negative herds. Positive herds were those in which an Actinobacillus pleuropneumoniae (App) strain of serotype 3, 5 or 7 was isolated and negative ones those in which there was no notification of clinical symptoms or lesions of swine pleuropneumoniae, no App isolation and the herd was under veterinarian control. The collected material was submitted to three different bacterial culture methods: 1- direct streak on solid selective medium, 2- dilution in selective broth followed by subculture in solid selective medium, and 3- dilution in selective broth medium followed by subculture in blood agar. Among the NAD-dependent strains recovered 86 were App, 13 belonged to the minor group and 21 to the Taxon group (C, D, E e F). From the positive herds four serotyped strains of App (sorotypes 3, 7 and 12) and 51 nonsorotipable strains were recovered. From the negative herds 31 nonsorotipable strains of App were recovered, indicating that App is a resident in the upper respiratory tract of pigs. The best method for recovering NAD-dependent strains from carrier piglets was achieved by direct culturing of tonsil tissue in solid selective medium (PPLO agar containing 2mu g of crystal violet, 10mu g of NAD, 1mu g of lincomycin, 1,4mu g of bacitracin per ml).

Secreções nasais, tonsilares e tecido tonsilar foram coletados de 67 leitões de 9 a 15 semanas de idade, provenientes de três rebanhos positivos para Actinobacillus pleuropneumoniae (App), e de 50 leitões 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 notificação de sintomas clínicos, lesões 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- diluição em caldo seletivo seguido de subsemeadura em meio de cultivo sólido seletivo; 3- diluição 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 não sorotipificáveis. Dos rebanhos negativos foram recuperadas 31 amostras de App não 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 leitões portadores foi da biópsia de tecido tonsilar semeado diretamente em meio sólido seletivo (PPLO ágar adicionado de 2mi g de cristal violeta, 10mi g NAD, 1mi g de lincomicina, 1,4mi g de bacitracina por ml).