Gabriel Jorge Sequeira

Impact of probiotic administration on the health and fecal microbiota of young calves: a meta-analysis of randomized controlled trials of lactic acid bacteria.

Before weaning, dairy calves are susceptible to many pathogens which can affect their subsequent performance. The use of lactic acid bacteria (LAB) has been identified as a tool to maintain the intestinal microbial balance and to prevent the establishment of opportunistic pathogenic bacterial populations. However, a consensus has not been reached as to whether probiotics may be effective in reducing the prevalence of gastrointestinal diseases in young calves. The aim of this meta-analysis was to assess the effect of probiotics on diarrhea incidence and the intestinal microbial balance. LAB supplementation has been shown to exert a protective effect and to reduce the incidence of diarrhea (relative risk, RR=0.437, 95% confidence interval (CI) 0.251-0.761). In the subanalysis, this protective effect of the probiotics against diarrhea was observed only in trials that used whole milk (RR=0.154, 95% CI 0.079-0.301) and trials that used multistrain inocula (RR=0.415, 95% CI 0.227-0.759). Probiotics did not improve the fecal characteristics (standardized mean difference, SMD=-0.4904, 95% CI -1.011-0.035) and were unable to change the LAB:coliforms ratio (SMD=0.016, 95% CI -0.701-0.733). Probiotics showed a beneficial impact on the LAB:coliforms ratio in the subanalysis that included trials that used whole milk (SMD=0.780, 95% CI 0.141-1.418) and monostrain inocula (SMD=0.990, 95% CI 0.340-1.641). The probability of significant effects (probiotic positive effect) in a new study was >0.70 for diarrhea and fecal consistency. Whole milk feeding improved the action of the probiotic effect on the incidence of diarrhea and LAB:coliforms ratio. The probability to find significant effects in the diarrhea frequency and LAB:coliforms ratio was higher (P>0.85) if the new studies were conducted using whole milk to feed calves. This paper defines the guidelines to standardize the experimental designs of future trials. LAB can be used as growth promoters in calves instead of antibiotics to counteract the negative effects of their widespread use.

Molecular microbial analysis of Lactobacillus strains isolated from the gut of calves for potential probiotic use.

The intestinal microbiota has an influence on the growth and health status of the hosts. This is of particular interest in animals reared using intensive farming practices. Hence, it is necessary to know more about complexity of the beneficial intestinal microbiota. The use of molecular methods has revolutionized microbial identification by improving its quality and effectiveness. The specific aim of the study was to analyze predominant species of Lactobacillus in intestinal microbial ecosystem of young calves. Forty-two lactic acid bacteria (LAB) isolated from intestinal tract of young calves were characterized by: Amplified Ribosomal DNA Restriction Analysis (ARDRA), by using Hae III, Msp I, and Hinf I restriction enzymes, and 16S rDNA gene sequencing. ARDRA screening revealed nine unique patterns among 42 isolates, with the same pattern for 29 of the isolates. Gene fragments of 16S rDNA of 19 strains representing different patterns were sequenced to confirm the identification of these species. These results confirmed that ARDRA is a good tool for identification and discrimination of bacterial species isolated from complex ecosystem and between closely related groups. This paper provides information about the LAB species predominant in intestinal tract of young calves that could provide beneficial effects when administered as probiotic.

Occurrence of thermotolerant Campylobacter spp. at different stages of the poultry meat supply chain in Argentina

AIMS: The objectives of this study were to investigate the occurrence and concentration of thermotolerant Campylobacter spp. at different stages of the poultry meat supply chain in Argentina. METHODS: Three integrated poultry companies were sampled. Each supply chain was considered at different stages from the reproductive farm to chicken meat at a retail market. The stages sampled were: (a) hens from breeder flocks, (b) eggs in the incubator, (c) broiler chickens in flocks (aged <1 week and >5 weeks), (d) chickens at a slaughterhouse, and (e) chicken meat at a retail market. The chickens sampled along each supply chain were in the same batch. Samples collected were: (a) cloacal samples from hens and chickens on the farms, (b) fertile eggs, (c) feed, water and litter from flocks, (d) chicken carcasses from the slaughterhouse and retail market, and (e) caeca and livers from the slaughterhouse. Samples obtained were examined for Campylobacter spp. The isolates were biotyped and the genus and species identified by PCR. Campylobacter spp. on chicken carcasses at slaughterhouse and retail market were enumerated. RESULTS: The highest proportions of Campylobacter positive samples were observed in carcasses at retail (25/30, 83.3%) and faecal samples from breeding hens (27/45, 60.0%). Only 3.3% (3/90) samples collected from broiler chickens aged <1 week were positive, but the percentage of positive samples had risen to 28.9% (26/90) by the end of the rearing period. The proportions of Campylobacter positive carcasses and caecal contents at the slaughterhouse were both 33.3% (10 of 30 samples each). The concentration of Campylobacter contamination observed on carcasses at retail markets ranged from no bacteria/carcass to 3.71 log10 cfu/carcass. CONCLUSIONS: The data obtained provide essential information for future quantitative risk assessments aiming to estimate the probability of a person contracting campylobacteriosis following consumption of broiler meat in Argentina. CLINICAL RELEVANCE: The proportions of Campylobacter-positive samples found in this preliminary study indicate that a large proportion of the cases of human gastroenteritis in Argentina may be due to this pathogen. Human cases of gastroenteritis should be studied in greater detail and measures should be developed to reduce the proportion of poultry products that are contaminated by Campylobacter species.

Pathogen translocation and histopathological lesions in an experimental model of Salmonella Dublin infection in calves receiving lactic acid bacteria and lactose supplements.

The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 109 CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 1010 CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection.

Quantitative Risk Assessment of Human Trichinellosis Caused by Consumption of Pork Meat Sausages in Argentina

In Argentina, there are three known species of genus Trichinella; however, Trichinella spiralis is most commonly associated with domestic pigs and it is recognized as the main cause of human trichinellosis by the consumption of products made with raw or insufficiently cooked pork meat. In some areas of Argentina, this disease is endemic and it is thus necessary to develop a more effective programme of prevention and control. Here, we developed a quantitative risk assessment of human trichinellosis following pork meat sausage consumption, which may be used to identify the stages with greater impact on the probability of acquiring the disease. The quantitative model was designed to describe the conditions in which the meat is produced, processed, transported, stored, sold and consumed in Argentina. The model predicted a risk of human trichinellosis of 4.88 × 10−6 and an estimated annual number of trichinellosis cases of 109. The risk of human trichinellosis was sensitive to the number of Trichinella larvae that effectively survived the storage period (r = 0.89), the average probability of infection (PPinf) (r = 0.44) and the storage time (Storage) (r = 0.08). This model allowed assessing the impact of different factors influencing the risk of acquiring trichinellosis. The model may thus help to select possible strategies to reduce the risk in the chain of by‐products of pork production.

Faecal culturable microbiota, growth and clinical parameters of calves supplemented with lactic acid bacteria and lactose prior and during experimental infection with Salmonella Dublin DSPV 595T

The aim of this study was to evaluate the probiotic inoculum + lactose effect on weight, intestinal culturable microbiota, morbidity and mortality of young ...

Identification of lactic acid bacteria with bio-preservative potential isolated from contaminated avian blood obtained at the slaughterhouse

La sangre es uno de los residuos mas contaminantes de la industria carnica, y a la vez es tiene diversas aplicaciones en la industria alimenticia animal. No obstante, dado que la sangre es altamente susceptible a la descomposicion microbiana, ella y sus fracciones suelen no estar disponibles para su uso como ingredientes en la industria alimenticia. La biopreservacion se presenta como una alternativa para mejorar la calidad de la sangre y de esta forma presentarla como un ingrediente en la elaboracion de productos alimenticios. El objetivo de este trabajo fue aislar e identificar bacterias acido lacticas (BAL) a partir de sangre aviar obtenida en mataderos industriales y evaluar su actividad antimicrobiana. Se aislaron 96 colonias presuntivas de BAL a partir de sangre aviar, las cuales fueron genotipificadas. Se estudiaron 31 BAL obtenidas a partir de diferentes muestras de sangre y se identificaron 11 grupos de bacterias diferentes a partir del analisis de restriccion del ADN microbiano. De estas, 28 produjeron compuestos antimicrobianos como acidos organicos, 11 generaron peroxido de hidrogeno (H2O2) y dos fueron productoras de sustancias tipo bacteriocinas. Estas ultimas, identificadas como Lactobacillus salivarias (DSPV 027SA) y Enterococcus faecalis (DSPV 008SA), inhibieron el crecimiento de Escherichia coli, Pseudomonas aeruginosa y algunos serotipos de Salmonella spp. De esta forma se lograron identificar dos cepas de BAL como potenciales candidatas para ser aplicadas en un sistema de biopreservacion de sangre aviar. Esta herramienta biotecnologica es mas economica que otras tecnicas de sanitizacion y reduciria el riesgo de transmision de microorganismos patogenos a lo largo de la cadena agroalimentaria.

Estudio epidemiológico de los casos de triquinelosis registrados en la provincia de Santa Fe, Argentina, 1998-2009

OBJETIVO: Caracterizar desde los puntos de vista epidemiologico, clinico y de laboratorio los casos y brotes de triquinelosis que se registraron en la provincia de Santa Fe, Argentina, entre 1998 y 2009. METODOS: Se analizaron 1 519 fichas epidemiologicas de personas que presentaron sintomas y signos compatibles con triquinelosis en la provincia de Santa Fe en el periodo 1998-2009. Se realizo el analisis estadistico descriptivo de la informacion contenida en las fichas epidemiologicas y los resultados clinicos y de laboratorio; se aplico el analisis bifactorial para determinar las posibles asociaciones con factores epidemiologicos y ambientales. RESULTADOS: Se encontraron sintomas de triquinelosis en 1 276 casos; 372 cumplian la definicion de caso clinico y 224 muestras resultaron positivas por inmunofluorescencia indirecta, independientemente de su clasificacion como caso clinico. Se identificaron 27 brotes que involucraron a 1 157 casos en ocho departamentos, con mayor frecuencia en el centro y el sur de la provincia. La distribucion anual de los casos asociados epidemiologicamente entre si fue heterogenea, con una mayor frecuencia en el periodo 2000-2003 y en los meses de agosto a octubre. Hubo mayor probabilidad de enfermar cuando se consumieron productos de fuentes informales (OR = 3,69; P = 0,014) y en las areas rurales (OR = 1,799; P = 0,011). El periodo de incubacion de la enfermedad (mediana) fue de 12 dias. Las personas que consumieron carne de cerdo o sus derivados tuvieron 2,06 veces mas riesgo de enfermar que las que no la consumieron. CONCLUSIONES: El mayor numero de brotes ocurrio en los departamentos mas poblados y con mayor produccion porcina. Se deben disenar acciones especificas de prevencion y control de la enfermedad en esos departamentos. Se debe considerar el analisis epidemiologico de riesgos al evaluar, gestionar y comunicar los riesgos sanitarios de triquinelosis.

Poultry blood from slaughterhouses: development of a biopreservation system to improve microbiological quality prior to transforming blood into by-products

Abstract The aim of this study was to investigate the use of indigenous lactic acid bacteria (LAB) with specific additives as a Biopreservation System (BS) for poultry blood during its storage in slaughterhouses. The BS consisted of two LAB (Enterococcus faecalis DSPV 008SA or Lactobacillus salivarius DSPV 032SA) with 4 additives (lactose 2 g/l, yeast extract 0.4 g/l, ammonium citrate 0.4 g/l and NaCl 1 g/l). After 24 h storage at 30ºC, lower counts of enterobacteria, coliforms, Pseudomonas spp. and Staphylococcus aureus were evident in blood treated with the BS than in untreated blood. The ability of LAB to prevent haemolysis was evident. A decrease in pH was associated with control of spoilage microorganisms but it needed to be regulated to prevent coagulation of proteins. On the basis of these results it is recommended to supplement blood with a BS to avoid undesirable changes during blood storage before processing.

Microbiota cultivable fecal, crecimiento y parámetros clínicos de terneros suplementados con bacterias ácido lácticas y lactosa previo y durante una infección experimental con Salmonella Dublin DSPV 595T

RESUMEN El objetivo de este trabajo fue evaluar el efecto del inoculo probiotico + lactosa sobre el peso, la microbiota intestinal, la morbilidad y la mortalidad de terneros jovenes desafiados con Salmonella Dublin DSPV 595T. Se utilizaron 24 terneros divididos en un grupo control (GC) y un grupo probiotico (GP). Al GP se le administro 100 g lactosa.ternero –1 .d –1 y 10 10 UFC.ternero-1.d –1 de cada cepa de un inoculo probiotico compuesto por Lactobacillus casei DSPV318T, Lactobacillus salivarius DSPV315T y Pediococcus acidilactici DSPV006T a lo largo de todo el experimento. El patogeno fue administrado el dia 11 del experimento, en una dosis oral de 10 9 UFC.animal –1 . Las poblaciones de Lactobacillus y levaduras fueron modificadas en el GP a causa de la administracion del inoculo + lactosa. La severidad de la diarrea fue menor en el GP. No se encontraron diferencias en el resto de los signos clinicos, el peso vivo y la mortalidad entre los dos grupos analizados. En este estudio, la administracion periodica de un inoculo probiotico de origen bovino y lactosa, favorecio el establecimiento de una microbiota intestinal mas estable y balanceada, aun durante una infeccion con