Low-cost culture medium for biomass production of lactic acid bacteria with probiotic potential destined to broilers / Desarrollo de un medio de cultivo de bajo costo para la producción de biomasa potencialmente probiótica destinado a pollos parrilleros

Abstract The aim of this study was to evaluate different low-cost culture media for biomass production of 3 potential probiotic L. salivarius strains, which could be destined to broilers at farms. Different formulated media based on whey permeate (WP) supplemented with nitrogenous sources were evaluated: yeast extract (YE), whey hydrolysate (WH) and MnSO..H.O (Mn), MgSO..7H.O (Mg). The growth of each strain in the formulated media and the cost was compared with their growth and cost in commercial medium (MRS). L. salivarius DSPV008P did not grow adequately in any of the formulated media. On the other hand, addition of YE and Mn in the formulated media increased L. salivarius DSPV002P and L. salivarius DPSV011P growth. In contrast, WH and Mg addition increased the L. salivarius DSPV002P biomass only. L. salivarius DSPV011P was the only strain that had similar growth performance in MRS as in the selected medium: WP + YE 8g/l + Mn. In this sense, L. salivarius DSPV011P reached a biomass of 9.22 Log (CFU/ml) in the selected formulated medium, with a low-cost growth medium 12 times less than in MRS. Although the effect of supplements added to the culture medium on kinetic parameters are strain dependent, L. salivarius DSPV011P is the strain with the best technological characteristics, capable of growing in a medium based on a by-product of the dairy industry supplemented with YE and Mn and at a much less cost than in MRS medium.

Resumen El objetivo de este trabajo fue evaluar diferentes medios de cultivo de bajo costo para la producción de biomasa de 3 cepas potencialmente probióticas de L. salivarius, las cuales podrían ser destinadas a pollos parrilleros en las granjas. Para ello se evaluaron diferentes formulaciones basadas en permeado de suero de queso (WP) suplementado con fuentes nitrogenadas: extracto de levadura (YE) e hidrolizado de suero (WH) y MnSO..H.O (Mn), MgSO..7H.O (Mg). El crecimiento de las cepas en estas formulaciones y el costo económico fue comparado con el crecimiento y costo en el medio de cultivo comercial (MRS). L. salivarius DSPV008P no creció adecuadamente en ninguno de los medios evaluados. Por otro lado, la adición del YE y Mg al medio mejoró el desarrollo microbiano de L. salivarius DSPV002P y L. salivarius DPSV011P. El agregado de WH y Mn solo tuvo un efecto positivo en el incremento de la biomasa de L. salivarius DSPV002P. L. salivarius DSPV011P fue la única cepa que desarrolló la misma cantidad de biomasa en MRS y en el medio seleccionado WP + YE 8 g/L + Mn. L. salivarius DSPV011P logró un desarrollo de biomasa de 9.22 Log (UFC/ml) en el medio seleccionado con un costo económico 12 veces menor que en MRS. Aunque el efecto de los suplementos añadidos al medio de cultivo sobre los parámetros cinéticos depende de la cepa, L. salivarius DSPV011P es la cepa con mejores características tecnológicas, capaz de crecer en un medio a base de un subproducto de la industria láctea suplementado con YE y Mn y a un costo mucho menor que en MRS.

Molecular epidemiology of Campylobacter jejuni isolates from the broiler production chain: first report of MLST profiles in Argentina.

Campylobacter jejuni is an important foodborne pathogen with global distribution. We describe a genotyping study of a collection of C. jejuni (n=137) isolated from different broiler farms and from multiple sites along the processing line in a slaughterhouse in Argentina during 2011, 2012 and 2015. The isolates were genotyped using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Based on the PFGE results, the isolates were grouped into 26 pulsotypes. Subsequently, the isolates representing these 26 pulsotypes were chosen for MLST genotyping, which identified 16 different sequence types (STs) and 6 clonal complexes (CCs) (21, 45, 48, 353, 354, 446). Several of the STs (n=7) have not been previously reported in the PubMLST.org database. The most prevalent CCs were 21, 45 (both associated with human campylobacteriosis worldwide) and 353. This study showed high genetic diversity among C. jejuni in the broiler production environment in Argentina with novel MLST genotypes.

Quantification of FITC-labelled probiotic Lactobacillus salivarius DSPV 001P during gastrointestinal transit in broilers.

The knowledge related to the fate of probiotics in the complex environment of the intestinal microbiota in broilers is just beginning to be elucidated; however, it is not yet well understood. A good method to investigate the mechanisms by which probiotics mediate their effects is to mark probiotic bacteria and trace them. The aim of this research was to develop a new method to estimate in vivo fluorescein isothiocyanate (FITC)-labelled Lactobacillus salivarius DSPV 001P counts during passage through the gastrointestinal tract (GIT) of broilers. Forty-five, 1 d old Cobb broilers were used in this trial. Programmed necropsies were performed 30 min, 6 h, and 12 h after the administration of the probiotic bacterium, and samples of liver, crop, duodenum, caecum, and bursa of fabricius were collected. To determine the spatial and temporal transit of L. salivarius DSPV 001P in broilers, the number of bacteria as well as its respective fluorescent signal produced by FITC were measured. In order to observe the relationship between the variables, a logistic regression analysis was applied. The amount of fluorescence could be used as an indicator of fluorescent probiotic bacteria in the crop and duodenum 30 min after probiotic bacterium supplementation. In addition, the fluorescent signal could be used to estimate bacterial counts in caecum 6 and 12 h after L. salivarius DSPV 001P administration. To the best of our knowledge, this research is the first in vivo trial to employ the bacterial FITC-labelling technique in order to enumerate probiotic bacteria during gastrointestinal transit in broilers.

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

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.

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.

Trasplante renal: experiencia 1975-1995 / Renal transplantion: experience 1975-1995

Presentamos los resultados obtenidos en 20 años de trasplante renal y sus complicaciones. Desde 1975, se han realizado 293 trasplantes renales de los cuales se revisaron los primeros 256 correspondientes a 238 pacientes. El origen del injerto correspondió a donante vivo en 57 por ciento y donante cadáver en 43 por ciento. La distribución por sexo fue de 93 mujeres y 145 hombres. El rango de edad de 10 a 66 años con unamedia de 33 años. La anastomosis venosa se realizó a la vena cava inferior en 52,3 por ciento y a vena ilíaca en 47,7 por ciento. La sutura arterial se realizó TT a la hipogástrica en 77.2 por ciento y TL a la ilíaca en 22.8 por ciento de los casos. El neoimplante ureteral se efectuó con la técnica de Gregoire en 87 por ciento y de Politano en 13 por ciento de los casos. El esquema de inmunosupresión que se utilizó fue la terapia biasociada con metilprednisolona y azathioprina y desde 1983 se cambió en fonna progresiva a el esquema triasociado con metilorednisolona, azathiprina y ciclosporina, el cual es usado actualmente en todos nuestros pacientes. A enero de 1996 tenemos 183 (71,6 por ciento) de injertos funcionantes. El seguimiento medio del injerto fue de 90 meses (rango de 1 a 252 meses). Tuvimos 73 injertos perdidos siendo la causa inmunológica la de mayor incidencia con 48 casos. Se realizaron 24 trasplantectomías, 22 por causa inmunológica. Tuvimos un total de 48 (17.75 por ciento) pacientes con complicaciones quirúrgicas, 34 urológicas, 12 vasculares y 8 linfoceles. Complicaciones médicas en 170 pacientes: 100 de tipo infeccioso diferentes a ITU y 70 con necrosis tubular aguda (NT A). Hay 33 (15 por ciento) pacientes fallecidos, 26 de causas relacionadas con el trasplante