Evaluation of oral supplementation of free and nanoencapsulated Minthostachys verticillata essential oil on immunological, biochemical and antioxidants parameters and gut microbiota in weaned piglets.

Early weaning is an important stressor that impairs the piglet´s health, and essential oils appear as promising candidates to improve it instead of antibiotics. The aim of this study was to evaluate the effect of oral supplementation of free and nanoencapsulated Minthostachys verticillata essential oil (EO and NEO, respectively) on immunological, biochemical and antioxidants parameters as well as on gut microbiota in weaned piglets. EO was extracted by hydrodistillation and nanoencapsulation was performed by high-energy method using Tween 80 and Span 60 as surfactants. EO and NEO were chemically analyzed by gas chromatography-mass spectrometry (GC-MS). The cytotoxic effects of both EO and NEO was evaluated on Caco-2 cell line. For in vivo assay, male weaned piglets (age: 28 days, mean initial body weight: 11.63 ± 0.37 kg) were randomly distributed in six groups of six animals each (n = 6) and received orally EO (10.0 mg/kg/day) or NEO (2.5, 5.0 and 10.0 mg/kg/day), named hereinafter as EO-10, NEO-2.5, NEO-5 and NEO-10, for 30 consecutive days. Animals not treated or treated with surfactants mixture were evaluated as control and vehicle control. Subsequently, histological, hematological and biochemical parameters, cytokines production, oxidative markers, CD4+/CD8+ T cells and gut microbiota were evaluated. GC-MS analysis was similar in both EO and NEO. The NEO was more toxic on Caco-2 cells than EO. Oral supplementation of EO-10 or NEO-10 improved growth performance compared to control group NEO-2.5 or NEO-5 (p < 0.05) groups. NEO-2.5, NEO-5 and NEO-10 did not alter the morpho-physiology of digestive organs and decreased malondialdehyde (MDA) levels in liver compared to control (p < 0.05) or EO-10 groups (p < 0.05, p < 0.01). In addition, NEO-10 showed an increase in CD4+/CD8+ T cells ratio (p < 0.001), and induced the highest serum levels of IL-10 (p < 0.01). Serum triglycerides levels were significantly lower in animals treated with EO-10 or NEO-2.5, NEO-5 and NEO-10 compared to control group (p < 0.001). Gut microbiota analysis showed that NEO-10 favor the development of beneficial intestinal microorganisms to improve parameters related to early weaning of piglets. In conclusion, EO and NEO improved parameters altered by early weaning in piglets however, NEO was safer and powerful. Therefore, NEO should be further studied to be applied in swine health.

Antimicrobial resistance profiles in Escherichia coli isolated from whole-chicken carcasses from conventional, antibiotic-free, and organic rearing systems / Perfil de resistência em Escherichia coli isoladas de carcaças de frango provenientes de sistemas de produção convencional, livre de antibióticos e orgânico

Antimicrobial resistance (AMR) is a growing concern in human and animal health. Public discussions on these issues have contributed to an increased demand for antibiotic-free food. Studies comparing the antimicrobial resistance profiles of bacteria in foodstuffs originating from farming systems with restrictions on the use of antimicrobials are scarce. This study aimed to assess the antimicrobial resistance profiles of generic Escherichia coli isolated from whole chickens originating from farming systems with and without restrictions on the use of antimicrobials. For this purpose, three groups of E. coli strains were formed: (GC) from chickens reared in conventional production systems, without restriction on the use of antimicrobials (n=72); (GL) from chickens reared in farming systems certified as free of any antibiotic use (n=72); and (GO) from chickens from an organic farming system (n=72). Whole chicken units were individually rinsed as recommended by ISO 17604:2015, and E. coli was isolated from the rinse suspension. To evaluate the resistance profile, E. coli strains were tested against 12 antimicrobials using broth microdilution or disk diffusion tests. Eighty strains (40.7%) were found to be fully susceptible to the tested antimicrobials, and 23.6% were multidrug resistant. The highest frequencies of resistance were observed to tetracycline (GC=37,5%; GL=34,7%; GO=25%) and trimethoprim (GC=27,8%; GL=34,7%; GO=22,2%). In the case of multidrug resistant strains, GC presented 32% (n=23) of strains with multidrug resistance characteristics whereas the GL and GO groups presented 22% (n=16) and 17% (n=12), respectively. As for the totally susceptible strains, a frequency of 56% of Tsus strains was observed in the organic group, whereas this frequency was 33% in the GC and GL groups. Using GC as a reference, the Poisson regression model showed a higher occurrence of fully susceptible E. coli strains, as well as lower frequencies of multidrug resistance and resistance to ampicillin and nalidixic acid in GO. The GL group exhibited the lowest frequency of ampicillin resistance. These observations suggest that the lower selection pressure for antimicrobial use in the farming system may be reflected in the resistance profile of bacteria present in foodstuffs purchased by consumers.(AU)

A resistência antimicrobiana (AMR) é uma preocupação crescente para a saúde humana e animal. A discussão pública dessas questões tem contribuído para o aumento da demanda por alimentos produzidos sem o uso de antibióticos. No entanto, estudos que comparem os perfis de resistência antimicrobiana de bactérias em alimentos oriundos de sistemas agrícolas com restrição ao uso de antimicrobianos ainda são escassos. O objetivo deste estudo foi avaliar o perfil de resistência antimicrobiana em Escherichia coli genérica isolada de carcaças de frangos inteiros oriundos de sistemas de criação com e sem restrições ao uso de antimicrobianos. Para tanto, três grupos de cepas de E. coli foram formados: (GC) isolados de carcaças de frangos criados no sistema convencional - sem restrição de uso de antimicrobianos (n=72); (GL) isolados de frangos de sistemas certificados sem uso de antimicrobianos (n=72); (GO) de frangos originados de produção orgânica (n=72). As unidades de frango inteiro foram submetidas à lavagem conforme recomendado pela ISO 17604: 2015 e E. coli foi isolada da suspensão de enxágue. Para avaliar o perfil de resistência, as cepas de E. coli foram testadas frente à 12 antimicrobianos pelos testes de microdiluição em caldo ou difusão em disco. Oitenta cepas (40,7%) foram totalmente suscetíveis aos antimicrobianos testados e 23,6% multirresistentes. As maiores frequências de resistência foram observadas frente a tetraciclina (GC=37,5%; GL=34,7%; GO=25%) e trimetoprima (GC=27,8%; GL=34,7%; GO=22,2%). No caso de cepas multirresistentes, GC apresentou 32% (n=23) das cepas com características de multirresistência enquanto os grupos GL e GO apresentaram 22% (n=16) e 17% (n=12), respectivamente. Quanto às cepas totalmente suscetíveis, foi observada uma frequência de 56% de cepas Tsus no grupo orgânico enquanto tal frequência foi de 33% nos grupos GC e GL. Utilizando GC como referência, o modelo de regressão de Poisson demonstrou maior ocorrência de cepas de E. coli totalmente suscetíveis, bem como menores frequências de multirresistência e resistência à ampicilina e ácido nalidíxico no GO. Em GL, apenas a frequência mais baixa de resistência à ampicilina pôde ser demonstrada. Essas observações sugerem que a menor pressão de seleção do uso de antimicrobianos no sistema de cultivo pode se refletir no perfil de resistência das bactérias presentes nos alimentos adquiridos pelo consumidor.(AU)

Phytochemistry and teratogenic potential of Mimosa tenuiflora (willd.) poir. (Fabaceae) in ruminants: A systematic review.

Mimosa tenuiflora (Willd.) Poir. (Fabaceae) is a plant native to Brazil and occurs in the phytogeographic domains of Caatinga and Cerrado. Relevant studies have investigated the chemical components of this plant and others have already demonstrated its teratogenic potential. It has been proven that this plant causes congenital malformations in farm animals and, consequently, financial losses to farmers in the Brazilian semiarid region. The present work aimed to carry out a bibliographic survey on the teratogenic effects of M. tenuiflora in ruminants and to group the chemical compounds occurring in this species. For this, databases were consulted and twenty-four articles published in the last 30 years (1990-2020) were included. According to the scientific documents analyzed, M. tenuiflora has embryotoxic, fetotoxic and abortive potential in farm animals, especially sheep and goats. The main classes of chemical compounds present in this species are alkaloids, saponins, flavonoids, and terpenoids. It is likely that some of these substances, mainly the indole alkaloid N,N-dimethyltryptamine, are related to the teratogenic effects reported in ruminants in the Brazilian semiarid region.

Percepção do consumidor de proteína animal sobre o bemestar dos animais de produção em Santarém, Pará, Brasil / Animal protein consumer's perception about the living of production animals in Santarém, Pará, Brazil / Percepción del consumidor de proteína animal sobre el bienestar de los animales de producción en Santarém, Pará, Brasil

Resumo As mudanças relacionadas à saúde e bem-estar dos animais tornaram-se cada vez mais relevantes no mundo, principalmente quando questionadas pelo mercado consumidor, que cobra do manejo produtivo a garantia sanitária e a qualidade no paladar da carne. O objetivo neste estudo é identificar a percepção do consumidor de produtos de origem animal sobre o bem-estar dos animais de produção, em Santarém, Pará, bem como sua disposição em adquirir esses produtos com preços diferenciados. A pesquisa foi realizada através de um questionário padrão de caráter fechado contendo 10 (dez) perguntas objetivas, com resposta apenas de sim ou não. Foram aplicados questionários para 402 pessoas, em diferentes locais, como: feiras e praças públicas. Os resultados apontaram que a maioria dos entrevistados reconhecem que os produtos de origem animal fazem parte da sua dieta diária, além disso, a maioria dos consumidores não possuem conhecimento sobre a temática bem-estar animal, bem como não estão dispostos a pagar mais pelo produto com selo de qualidade, e não demonstraram interesse e/ ou preocupação com o modo de criação ou abate dos animais.

Abstract As changes related to the health and well-being of the animals used, they are increasingly relevant in the world, especially when questioned by the consumer market, which charges the productive product of health guarantee and quality in the taste of the meat. The aim of this study is to identify the consumer perception of products of animal origin about the welfare of farm animals in Santarém, Pará, as well as their selection to purchase these products at different prices. A survey was carried out using a standard closed-ended questionnaire containing 10 (ten) objective questions, with an answer only yes or no. There were questionnaires for 402 people, in different places, such as: fairs and public squares. The results pointed out to the majority of respondents recognized that animal products are part of their daily diet, in addition, most consumers are unaware of the animal welfare theme, as well as are not willing to pay more for the product with quality seal, and showed no interest and / or concern with the way animals are raised or slaughtered.

Resumen Los cambios relacionados con la salud y bienestar de los animales se convirtieron cada vez más relevantes en el mundo, principalmente cuando cuestionados por el mercado consumidor, que cobra del manejo productivo la garantía sanitaria y la calidad en el paladar de la carne. El objetivo en este estudio es identificar la percepción del consumidor de productos de origen animal sobre el bienestar de los animales de producción, en Santarém, Pará, así como su disposición en adquirir esos productos con precios diferenciados. La investigación fue realizada a través de un cuestionario patrón de carácter cerrado conteniendo 10 (diez) preguntas objetivas, con respuesta solo de sí o no. Fueron aplicados cuestionarios para 402 personas, en diferentes locales, como: ferias y plazas públicas. Los resultados apuntaron que la mayoría de los entrevistados reconocen que los productos de origen animal hacen parte de su dieta diaria, además, la mayoría de los consumidores no poseían conocimiento sobre la temática bienestar animal, así como no están dispuestos en pagar más por el producto con sello de calidad, y no demostraron interés o preocupación con el modo de creación o abate de los animales.

Poisoning by Senecio brasiliensis in horses in northern Rio Grande do Sul

Background: In various regions of Brazil, horses and cattle are considered the most susceptible animals to plant poisoning. The plants of the genus Senecio are the most important in Rio Grande do Sul because they have the active principleknown as the pyrrolizidine alkaloid. Its diagnosis is made through epidemiology, clinical signs and histopathologicalanalysis, either of the tissues obtained by biopsy or necropsy. The objective of this study was to report and characterizethe epidemiological, clinical and anatomopathological findings of three cases of natural poisoning by Senecio brasiliensisin horses assisted at the Hospital Veterinário (HV) of the Universidade de Passo Fundo (UPF).Cases: Three traction horses, two males and one female, were admitted at the HV-UPF for clinical care. The animals werepresenting anorexia, weight loss, dysmetria, proprioceptive deficit and signs suggestive of colic. The epidemiological studyrevealed that the sites where these animals were located were infested by Senecio brasiliensis. The support therapy usedfor equine colic in all three cases was unsuccessful. One of the animals died and the other two were euthanized, all threeof them being reffered for necropsy. The post-mortem findings were mainly found in the liver, which showed accentuationof the lobular pattern and the appearance of nutmeg. During necropsy, fragments of organs from thoracic and abdominalcavities and central nervous system were collected and fixed in 10% buffered formalin. Subsequently, the samples wereprocessed chemically, submitted to cuts of five micrometers of thickness and stained with hematoxylin and eosin for microscopic analysis. Microscopically, the liver of all three horses presented megalocytosis, fibrosis and bile ducts hyperplasia.In the central nervous system, spongiosis and the presence of Alzheimer type II astrocytes were observed. Thus, throughthe association of information, the diagnosis of...(AU)

Plantas relatadas como tóxicas para ruminantes no semiárido nordestino / Plants reported as toxic to ruminants in the Brazilian northeastern semiarid region

Ao longo dos anos as intoxicações por plantas têm causado prejuízos significativos para os criadores de ruminantes de várias regiões do Brasil, afetando de forma direta o setor pecuário do país. Desta forma, objetivou-se realizar um levantamento com produtores, médicos veterinários, zootecnistas, engenheiros agrônomos e técnicos agrícolas sobre as principais plantas que causam intoxicações em ruminantes no Curimataú Paraibano. O presente trabalho foi realizado em cinco municípios da microrregião do Curimataú Ocidental Paraibano, incluindo Barra de Santa Rosa, Cuité, Damião, Nova Floresta e Sossego. As entrevistas foram realizadas por meio de três formulários estruturados, contendo indagações específicas sobre casos de intoxicações identificados na referida microrregião. Para a realização desta pesquisa, foram entrevistados 30 participantes (6 representantes de cada município) entre os meses de junho e outubro de 2016. A partir dos dados obtidos por meio das entrevistas, verificou-se que as principais plantas comprovadamente tóxicas do Curimataú Ocidental Paraibano, segundo os entrevistados, foram: Anadenanthera colubrina, Mascagnia rigida, Prosopis juliflora e Manihot glaziovii. Muitos entrevistados demonstram não conhecer o princípio tóxico de outras plantas presentes na região e citadas na literatura como responsáveis por intoxicações em ruminantes, tais como: Mimosa tenuiflora, Crotalaria retusa e a Solanum paniculatum. As plantas Physalis angulata e Ricinus communis foram mencionadas como tóxicas, mas estudos toxicológicos devem ser realizados para comprovar a toxicidade das mesmas. Tais resultados demonstram que são necessárias medidas profiláticas eficazes nas propriedades rurais, evitando, assim, a ocorrência de surtos e mortes de ruminantes.(AU)

Over the years the plant poisonings have caused significant losses to ruminant producers from various Brazilian regions, affecting the livestock sector in the country. Thus, this study aims to conduct a survey with producers, veterinarians, zootechnists, agronomists and agricultural technicians about the major plants poisoning ruminants in the Curimataú Paraibano. This study was conducted in five cities in the Curimataú Ocidental Paraibano, including Barra de Santa Rosa, Cuité, Damião, Nova Floresta and Sossego. The interviews were conducted through three structured forms, containing specific questions about poisoning cases identified in the microregion cited. To carry out this survey, a total of 30 participants were interviewed (six representatives from each city) between June and October 2016. From the data obtained from the interviews, one found the main toxic plants in Curimataú Ocidental Paraibano, from the viewpoint of those interviewed, were: Anadenanthera colubrina, Mascagnia rigida, Prosopis juliflora, and Manihot glaziovii. Many interviewees demonstrate they don't know the toxic principle of other plants present in the region and cited in the literature as responsible for poisoning in ruminants, such as: Mimosa tenuiflora, Crotalaria retusa and Solanum paniculatum. The plants Physalis angulata and Ricinus communis were mentioned as toxic, but new experiments must be carried out to prove their toxicity. These results show effective prophylactic measures are necessary in rural properties, thus preventing the occurrence of outbreaks and deaths of ruminants.(AU)

Poisoning by Senecio brasiliensis in horses in northern Rio Grande do Sul

Background: In various regions of Brazil, horses and cattle are considered the most susceptible animals to plant poisoning. The plants of the genus Senecio are the most important in Rio Grande do Sul because they have the active principleknown as the pyrrolizidine alkaloid. Its diagnosis is made through epidemiology, clinical signs and histopathologicalanalysis, either of the tissues obtained by biopsy or necropsy. The objective of this study was to report and characterizethe epidemiological, clinical and anatomopathological findings of three cases of natural poisoning by Senecio brasiliensisin horses assisted at the Hospital Veterinário (HV) of the Universidade de Passo Fundo (UPF).Cases: Three traction horses, two males and one female, were admitted at the HV-UPF for clinical care. The animals werepresenting anorexia, weight loss, dysmetria, proprioceptive deficit and signs suggestive of colic. The epidemiological studyrevealed that the sites where these animals were located were infested by Senecio brasiliensis. The support therapy usedfor equine colic in all three cases was unsuccessful. One of the animals died and the other two were euthanized, all threeof them being reffered for necropsy. The post-mortem findings were mainly found in the liver, which showed accentuationof the lobular pattern and the appearance of nutmeg. During necropsy, fragments of organs from thoracic and abdominalcavities and central nervous system were collected and fixed in 10% buffered formalin. Subsequently, the samples wereprocessed chemically, submitted to cuts of five micrometers of thickness and stained with hematoxylin and eosin for microscopic analysis. Microscopically, the liver of all three horses presented megalocytosis, fibrosis and bile ducts hyperplasia.In the central nervous system, spongiosis and the presence of Alzheimer type II astrocytes were observed. Thus, throughthe association of information, the diagnosis of...

Plantas relatadas como tóxicas para ruminantes no semiárido nordestino / Plants reported as toxic to ruminants in the Brazilian northeastern semiarid region

Ao longo dos anos as intoxicações por plantas têm causado prejuízos significativos para os criadores de ruminantes de várias regiões do Brasil, afetando de forma direta o setor pecuário do país. Desta forma, objetivou-se realizar um levantamento com produtores, médicos veterinários, zootecnistas, engenheiros agrônomos e técnicos agrícolas sobre as principais plantas que causam intoxicações em ruminantes no Curimataú Paraibano. O presente trabalho foi realizado em cinco municípios da microrregião do Curimataú Ocidental Paraibano, incluindo Barra de Santa Rosa, Cuité, Damião, Nova Floresta e Sossego. As entrevistas foram realizadas por meio de três formulários estruturados, contendo indagações específicas sobre casos de intoxicações identificados na referida microrregião. Para a realização desta pesquisa, foram entrevistados 30 participantes (6 representantes de cada município) entre os meses de junho e outubro de 2016. A partir dos dados obtidos por meio das entrevistas, verificou-se que as principais plantas comprovadamente tóxicas do Curimataú Ocidental Paraibano, segundo os entrevistados, foram: Anadenanthera colubrina, Mascagnia rigida, Prosopis juliflora e Manihot glaziovii. Muitos entrevistados demonstram não conhecer o princípio tóxico de outras plantas presentes na região e citadas na literatura como responsáveis por intoxicações em ruminantes, tais como: Mimosa tenuiflora, Crotalaria retusa e a Solanum paniculatum. As plantas Physalis angulata e Ricinus communis foram mencionadas como tóxicas, mas estudos toxicológicos devem ser realizados para comprovar a toxicidade das mesmas. Tais resultados demonstram que são necessárias medidas profiláticas eficazes nas propriedades rurais, evitando, assim, a ocorrência de surtos e mortes de ruminantes.

Over the years the plant poisonings have caused significant losses to ruminant producers from various Brazilian regions, affecting the livestock sector in the country. Thus, this study aims to conduct a survey with producers, veterinarians, zootechnists, agronomists and agricultural technicians about the major plants poisoning ruminants in the Curimataú Paraibano. This study was conducted in five cities in the Curimataú Ocidental Paraibano, including Barra de Santa Rosa, Cuité, Damião, Nova Floresta and Sossego. The interviews were conducted through three structured forms, containing specific questions about poisoning cases identified in the microregion cited. To carry out this survey, a total of 30 participants were interviewed (six representatives from each city) between June and October 2016. From the data obtained from the interviews, one found the main toxic plants in Curimataú Ocidental Paraibano, from the viewpoint of those interviewed, were: Anadenanthera colubrina, Mascagnia rigida, Prosopis juliflora, and Manihot glaziovii. Many interviewees demonstrate they don't know the toxic principle of other plants present in the region and cited in the literature as responsible for poisoning in ruminants, such as: Mimosa tenuiflora, Crotalaria retusa and Solanum paniculatum. The plants Physalis angulata and Ricinus communis were mentioned as toxic, but new experiments must be carried out to prove their toxicity. These results show effective prophylactic measures are necessary in rural properties, thus preventing the occurrence of outbreaks and deaths of ruminants.

Efficacy of leptospiral commercial vaccines on the protection against an autochtonous strain recovered in Brazil

In swine and bovines, leptospirosis prevention and control is carried out via vaccination of susceptible animals using bacterins. However, the efficiency of leptospirosis vaccines has been questioned. This work aimed to investigate the potency of five leptospirosis vaccines sold commercially in Brazil, challenging the animals with one autochthonous strain of Leptospira, Canicola serovar, denoted LO4, isolated from swine. The standard protocol was followed, and renal carriers of Leptospira were identified among the surviving animals by culture and PCR. Of the five vaccines tested, only two proved effective. None of the surviving animals was positive by culture; however, one animal was positive by PCR. Three of the five vaccines sold commercially in Brazil for the immunization of swine or bovines failed the test of the efficacy to protect the vaccinated animals following challenge with an autochthonous Leptospira strain, Canicola serovar. The two vaccines provided protection against the renal carrier state in the surviving animals. The criteria used to produce leptospirosis bacterins sold commercially in Brazil must be reviewed. The industry should support researches on leptospiral vaccinology to improve the quality of the present vaccines and discover new immunogenic strains, because it is known that vaccination is one of the most important tools to increase the reproduction rates in livestock.(AU)

Efficacy of leptospiral commercial vaccines on the protection against an autochtonous strain recovered in Brazil

Abstract In swine and bovines, leptospirosis prevention and control is carried out via vaccination of susceptible animals using bacterins. However, the efficiency of leptospirosis vaccines has been questioned. This work aimed to investigate the potency of five leptospirosis vaccines sold commercially in Brazil, challenging the animals with one autochthonous strain of Leptospira, Canicola serovar, denoted LO4, isolated from swine. The standard protocol was followed, and renal carriers of Leptospira were identified among the surviving animals by culture and PCR. Of the five vaccines tested, only two proved effective. None of the surviving animals was positive by culture; however, one animal was positive by PCR. Three of the five vaccines sold commercially in Brazil for the immunization of swine or bovines failed the test of the efficacy to protect the vaccinated animals following challenge with an autochthonous Leptospira strain, Canicola serovar. The two vaccines provided protection against the renal carrier state in the surviving animals. The criteria used to produce leptospirosis bacterins sold commercially in Brazil must be reviewed. The industry should support researches on leptospiral vaccinology to improve the quality of the present vaccines and discover new immunogenic strains, because it is known that vaccination is one of the most important tools to increase the reproduction rates in livestock.

Efficacy of leptospiral commercial vaccines on the protection against an autochtonous strain recovered in Brazil.

In swine and bovines, leptospirosis prevention and control is carried out via vaccination of susceptible animals using bacterins. However, the efficiency of leptospirosis vaccines has been questioned. This work aimed to investigate the potency of five leptospirosis vaccines sold commercially in Brazil, challenging the animals with one autochthonous strain of Leptospira, Canicola serovar, denoted LO4, isolated from swine. The standard protocol was followed, and renal carriers of Leptospira were identified among the surviving animals by culture and PCR. Of the five vaccines tested, only two proved effective. None of the surviving animals was positive by culture; however, one animal was positive by PCR. Three of the five vaccines sold commercially in Brazil for the immunization of swine or bovines failed the test of the efficacy to protect the vaccinated animals following challenge with an autochthonous Leptospira strain, Canicola serovar. The two vaccines provided protection against the renal carrier state in the surviving animals. The criteria used to produce leptospirosis bacterins sold commercially in Brazil must be reviewed. The industry should support researches on leptospiral vaccinology to improve the quality of the present vaccines and discover new immunogenic strains, because it is known that vaccination is one of the most important tools to increase the reproduction rates in livestock.

Efficacy of leptospiral commercial vaccines on the protection against an autochtonous strain recovered in Brazil

Abstract In swine and bovines, leptospirosis prevention and control is carried out via vaccination of susceptible animals using bacterins. However, the efficiency of leptospirosis vaccines has been questioned. This work aimed to investigate the potency of five leptospirosis vaccines sold commercially in Brazil, challenging the animals with one autochthonous strain of Leptospira, Canicola serovar, denoted LO4, isolated from swine. The standard protocol was followed, and renal carriers of Leptospira were identified among the surviving animals by culture and PCR. Of the five vaccines tested, only two proved effective. None of the surviving animals was positive by culture; however, one animal was positive by PCR. Three of the five vaccines sold commercially in Brazil for the immunization of swine or bovines failed the test of the efficacy to protect the vaccinated animals following challenge with an autochthonous Leptospira strain, Canicola serovar. The two vaccines provided protection against the renal carrier state in the surviving animals. The criteria used to produce leptospirosis bacterins sold commercially in Brazil must be reviewed. The industry should support researches on leptospiral vaccinology to improve the quality of the present vaccines and discover new immunogenic strains, because it is known that vaccination is one of the most important tools to increase the reproduction rates in livestock.