oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 30 matches for " Oyarzabal "
All listed articles are free for downloading (OA Articles)
Page 1 /30
Display every page Item
Líneas de ratones originales como modelos experimentales en genética y mejoramiento animal
Oyarzabal,M. I.;
BAG. Journal of basic and applied genetics , 2011,
Abstract: the long-term selection experiments allow to study the limits for the response to artificial selection and the consequences in other unselected characters. the selected lines used in this type of experiments, generally, had a ne>40 and they are originated from outbreed populations with a wide genetic basis. nevertheless, in 1986, at the faculty of veterinary sciences, national university of rosario, argentina, two lines of two-way selection for body weight were founded with animals of an unselected cf1 mice population with ne<40. the theoretical estimate of the initial genetic variance of the founders was closed to zero because of the cf1 strain, like anyone strain, was originated from 20 generations of full sibs matings. the results of 60 generations of selection are presented. the consequences of the selection in other characters related with fitness and with production were also studied. the response to selection demostrated the conservation of genetic variance in the founders and the presence of non-additive genetic components. the fitness deterioration of the selected lines led to a decrease in the production efficiency when they are compared with the non-selected line. in the long-term, selection for weight allowed to obtain heavier individuals but fitness was reduced. this implies a high selection cost that translates in a low production when the process is evaluated at a population level. a modification to the lerner's model of genetic homeostasis with greater fitness for the intermediate phenotypes was proposed to explain these results.
Prevalence of Campylobacter spp. in skinless, boneless retail broiler meat from 2005 through 2011 in Alabama, USA
Williams Aretha,Oyarzabal Omar A
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-184
Abstract: Background The prevalence of Campylobacter spp. in 755 skinless, boneless retail broiler meat samples (breast, tenderloins and thighs) collected from food stores in Alabama, USA, from 2005 through 2011 was examined. Campylobacter spp. were isolated using enrichment and plate media. Isolates were identified with multiplex PCR assays and typed with pulsed field gel electrophoresis (PFGE). Data were analyzed by nominal variables (brand, plant, product, season, state and store) that may affect the prevalence of these bacteria. Results The average prevalence of Campylobacter spp. in retail broiler meat for these years was 41%, with no statistical differences in the prevalence by year (P > 0.05). Seasons did not affect the prevalence of C. jejuni but statistically affected the prevalence of C. coli (P < 0.05). The prevalence by brand, plant, product, state and store were different (P < 0.05). Establishments from two states had the highest prevalence (P < 0.05). C. coli and C. jejuni had an average prevalence of 28% and 66%, respectively. The prevalence of C. coli varied by brand, plant, season, state, store and year, while the prevalence of C. jejuni varied by brand, product, state and store. Tenderloins had a lower prevalence of Campylobacter spp. than breasts and thighs (P < 0.05). Although no statistical differences (P > 0.05) were observed in the prevalence of C. jejuni by season, the lowest prevalence of C. coli was recorded from October through March. A large diversity of PFGE profiles was found for C. jejuni, with some profiles from the same processing plants reappearing throughout the years. Conclusions The prevalence of Campylobacter spp. did not change during the seven years of the study; however, it did change when analyzed by brand, product and state. Seasons did not affect the prevalence of C. jejuni, but they did affect the prevalence of C. coli. Larger PFGE databases are needed to assess the temporal reoccurrence of PFGE profiles to help predict the risk associated with each profile.
Propuesta de un sistema de seguimiento y alerta para la gestión de espacios protegidos: el caso del Parque Natural Cabo de Gata-Níjar (Almería, Espa a)
M. Oyarzabal,C. Oyonarte,A. Giorno
Ecosistemas , 2008,
Abstract: La mayoría de las áreas protegidas del mundo carecen de un sistema de seguimiento y alerta con implicancias directas en la gestión. Este trabajo propone, a partir del caso del Parque Natural Cabo de Gata-Níjar, posibles aplicaciones de un sistema de seguimiento. El sistema está basado en la más moderna tecnología satelital y fue originalmente desarrollado para uso agropecuario. En concreto, se propone la caracterización en un contexto histórico del funcionamiento de la vegetación del Parque, la descripción espacialmente explícita de la heterogeneidad y de la tendencia temporal en el funcionamiento de la vegetación, la aplicación de un sistema de alerta temprana de detección de cambios ecosistémicos, y la evaluación de la idoneidad del Parque en términos del funcionamiento de la vegetación que alberga. El sistema genera mensualmente información apropiada para gestores y podría aplicarse a un amplio abanico de áreas protegidas terrestres.
Shock anafiláctico en paciente con quiste hidatídico Anaphylactic shock in a patient with hydatidic cyst
L. Zubiaurre,I. Oyarzabal,A. Beguiristain
Revista Espa?ola de Enfermedades Digestivas , 2005,
Abstract:
Estructura Testicular y Calidad Seminal en Ratones Seleccionados por Peso
Bernardi,Sandra; Brogliatti,Guillermo; Oyarzabal,María Inés;
International Journal of Morphology , 2010, DOI: 10.4067/S0717-95022010000300004
Abstract: reproductive female capacity was affected by the genetic selection performed in a pair of lines of two-way selection of body weight for 50 generations (s: downward selection; s?: upward selection). these lines were originated from a control cf1 mice population (t) at the faculty of veterinary sciences (unr). the existence of reproductive differences attributed to the male genotype in the litter size and in the interval from the service beginning to first parturition was proven. with the aim of explaining them, the testicular structure - testicular weight (ptest), vas deferens diameter (dts), epithelium height (aes) - and the semen quality - spermatozoa number (ne), abnormal cell percentage (an), motility and movement of spermatic cells (casa parameters) were compared, in adult males between 10 and 14 weeks of age. the means of the dts and aes were estimated for 100 seminiferous tubules per individual. semen was obtained from the caudal portion of the epididymides and vasa deferentia. sperm count was performed in neubauer hemocytometer and abnormal cell percentage was estimated over 100 spermatozoa per sample. motility parameters were determined with a ceros 12.1 semen computerized analyzer. body weight selection occasioned significant differences between lines in the same way of the selection performed for ptest, aes and ne. males of the heaviest line (s?) show heavier testicles, higher seminiferous epithelium and, consequently, a higher number of spermatozoa when compared with s and t males (p<0,05). semen quality under the employed setup conditions was similar for males of the three lines. therefore, semen quality does not contribute to the explanation of the fertility differences between lines.
Efectos de la Selección y de la Superovulación en las Pérdidas Gestacionales de Ratonas CF1
Bernardi,S. F; Brogliatti,G; Oyarzabal,M. I;
International Journal of Morphology , 2011, DOI: 10.4067/S0717-95022011000100035
Abstract: the ovarian structure was modified as a consequence of weight selection in a pair of mouse lines selected for high (s') and low weight (s). lines were founded from an unselected population of cf1 strain (t). the follicle diameter and the number of the ovarian follicles and the corpora lutea were higher in s' females, but they did not reach a larger litter size at birth, may be, by an increase in the gestational losses. in these lines, the co-effects of long-term weight selection and ovarian stimulation were tested to evaluate if they increased gestational losses. two groups of females per line were employed: without and with ovarian stimulation (5ui of ecg and 5ui of hcg). females were slaughtered at 56-72hs and at 7 days post-breeding and after first parturition. the number of corpora lutea (cl), embryos (e) and implantation sites (si), and litter size at birth (tc) were observed. total losses (pt) and corpora lutea (pcl), embryo (pe) and fetus (pf) losses were estimated. mean cl, e, si and tc varied in the same direction of the selection made and they were significantly higher (p<0.05) in stimulated females, though not for tc. line s' had a higher reproductive potential but a greater biological cost (higher and later gestational mortality) when compared with the other lines. ovarian stimulation produced lower total reproductive efficiencies for the three lines and higher and later gestational losses, mainly for implantation sites. females from unselected line (t), without ovarian stimulation, with intermediate weights, bore larger litters, starting from an intermediate number of cl, e and si, with a lower and earlier embryo mortality, showing to be the most efficient from a reproductive and productive point of view.
Selección por tama?o de camada en conejos para carne
Antonini,Alicia G.; Corva,Santiago G.; Oyarzabal,María Inés;
BAG. Journal of basic and applied genetics , 2008,
Abstract: in rabbits, most of selection programs are mainly focused on prolificacy and indirectly, with low pressure, on fertility, thus rejecting sterile females. the aim of this work was to evaluate selection response to weaning litter size (tcd) on meat rabbits during seven generations and to estimate heritabilities and genetic correlations with total birth litter size (tct) and alive birth litter size (tcv). records for litter size, fertility and survival (on 390 does with two or more pregnancies mated with 63 males) were analyzed. selection differentials, selection responses, genetic correlations and heritabilities were calculated. the selection differentials were positive in all the generations, nevertheless, the observed selection responses oscillated between positive and negative values not allowing to establish a tendency in none of the studied characters (regression coefficients of each character on generations: btct=-0.02, btcv=-0.03, btcd=-0.27; p>0.05). despite the fact that the selection was based on litter size, there were no increases on selected character and its correlated characters (tct and tcv). natural selection was not the reason of this absence of response. heritability low values indicated that phenotypic variability is due to non additive effects, environmental effects or their interactions and could explain these results.
Efectos de la Selección y de la Superovulación en las Pérdidas Gestacionales de Ratonas CF1 Effects of Selection and Superovulation on Gestational Losses in CF1 Mice
S. F Bernardi,G Brogliatti,M. I Oyarzabal
International Journal of Morphology , 2011,
Abstract: En un par de líneas de ratones seleccionadas para alto (s') y bajo peso (s), originadas a partir de una población no seleccionada de la cepa CF1 (t), se modificó la estructura ovárica. El diámetro de los folículos ováricos y el número de folículos y de cuerpos lúteos se incrementaron en las hembras de la línea s', sin expresarse en un mayor tama o de camada al nacimiento, posiblemente, por un aumento de las pérdidas gestacionales. Se probó si los efectos conjuntos de la selección de peso a largo plazo y de la estimulación ovárica incrementaban las pérdidas gestacionales. Se utilizaron dos grupos de hembras por línea: sin y con estimulación ovárica (5UI de eCG y 5UI de hCG). Las hembras se sacrificaron a las 56-72 hs y a los 7 días postservicio y después de la primera parición. Se observaron los números de cuerpos lúteos (CL), embriones (E) y sitios de implantación (SI) y el tama o de camada al nacimiento (TC). Se estimaron las pérdidas totales (PT) y las pérdidas de cuerpos lúteos (PCL), de embriones (PE) y de fetos (PF). Los promedios de CL, E, SI y TC variaron en el mismo sentido de la selección practicada y fueron significativamente mayores (P<0,05) para las hembras estimuladas, a excepción de TC. La línea s' tuvo un potencial reproductivo superior pero un mayor costo biológico (mayor PT y más tardía) cuando se la comparó con las otras líneas. La estimulación ovárica produjo menores eficiencias reproductivas totales para las tres líneas y pérdidas gestacionales mayores y más tardías, principalmente de SI. Las hembras de la línea no seleccionada (t), no estimuladas, con pesos intermedios, parieron un mayor número de crías, partiendo de un número intermedio de CL, E y SI, con una menor y más temprana mortalidad embrionaria, demostrando ser las más eficientes desde el punto de vista reproductivo y productivo. The ovarian structure was modified as a consequence of weight selection in a pair of mouse lines selected for high (s') and low weight (s). Lines were founded from an unselected population of CF1 strain (t). The follicle diameter and the number of the ovarian follicles and the corpora lutea were higher in s' females, but they did not reach a larger litter size at birth, may be, by an increase in the gestational losses. In these lines, the co-effects of long-term weight selection and ovarian stimulation were tested to evaluate if they increased gestational losses. Two groups of females per line were employed: without and with ovarian stimulation (5UI of eCG and 5UI of hCG). Females were slaughtered at 56-72hs and at 7 days post-breeding and after fir
Estructura Testicular y Calidad Seminal en Ratones Seleccionados por Peso Testicular Structure and Semen Quality in Mice Lines Selected for Weight
Sandra Bernardi,Guillermo Brogliatti,María Inés Oyarzabal
International Journal of Morphology , 2010,
Abstract: La capacidad reproductiva femenina se modificócomo consecuencia de la selección de peso realizada en un par de líneas de selección divergente durante 50 generaciones (s: bajo peso; s’: alto peso), originadas a partir de una población testigo (t) de ratones CF1 y criadas en la Facultad de Ciencias Veterinarias (UNR). Se probó la existencia de diferencias reproductivas atribuibles al genotipo paterno observadas en el tama o de camada al nacimiento y en los días transcurridos desde el ingreso a servicio hasta la parición. Con el propósito de explicar las diferencias se comparó la estructura testicular - peso testicular (PTEST), diámetro del túbulo seminífero (DTS), altura de su epitelio (AES) - y la calidad seminal - número de espermatozoides (NE), porcentaje de células anormales (AN), motilidad y desplazamiento de las células espermáticas (Parámetros CASA) -, en machos adultos de 10 a 14 semanas de edad. Se estimó el promedio del DTS y AES en 100 túbulos seminíferos por individuo. El semen se obtuvo de la porción caudal de los epidídimos y de los conductos deferentes. El recuento de espermatozoides se realizó en cámara de Neubauer hemocitométrica y el porcentaje de células anormales se calculó sobre 100 espermatozoides por extendido. Los parámetros de motilidad se determinaron con analizador computarizado de semen Ceros 12.1. La selección por peso diferenciósignificativamente a las líneas en el mismo sentido de la selección practicada para PTEST, AES y NE. Los machos de la línea más pesada (s’) presentaron PTEST y AES mayores y tuvieron un mayor número de espermatozoides al compararlos con los de las líneas s y t (p<0,05). La calidad del semen, bajo las condiciones del setup utilizado, fue similar para los machos de las tres líneas. Por lo tanto, la calidad del semen no aportóa la explicación de las diferencias de fertilidad masculina entre las líneas. Reproductive female capacity was affected by the genetic selection performed in a pair of lines of two-way selection of body weight for 50 generations (s: downward selection; s’: upward selection). These lines were originated from a control CF1 mice population (t) at the Faculty of Veterinary Sciences (UNR). The existence of reproductive differences attributed to the male genotype in the litter size and in the interval from the service beginning to first parturition was proven. With the aim of explaining them, the testicular structure - testicular weight (PTEST), vas deferens diameter (DTS), epithelium height (AES) - and the semen quality - spermatozoa number (NE), abnormal cell percentage (AN), motility and
Alteraciones en el largo de la cola y su asociación con caracteres de fertilidad en ratones CF1 seleccionados por peso
Bernardi,S.F.; Tarallo,A; Faletti,C; Oyarzabal,M.I.;
InVet , 2011,
Abstract: in a control population (t) and in two pairs of lines of two-way selection for body weight (s and h: downward selection; s’ and h’: upward selection), mice with tail alterations and absence of caudal vertebrae were presented with low frecuency from line foundation. to estimate the relations among tail length (lc), number of caudal vertebrae (v), weight (p) and fertility characters, lc was measured in mm, v was counted by x-rays, structural characters in ovaries and testicles were observed by optical microscopy. it was tested, by anova and multiple comparisons tests, that lines differed in lc (p0,05) in the same way of the weigth selection performed (males: lch=8,4; lcs=8,8; lct=9,0; lch’=9,2; lcs’=9,8). the mice with caudal vertebrae absences (cc) had, in average, half of the v than the animals with phenotypically normal tails (cn). males and females presented smaller gonads, minor seminiferous tubule diameter in males and minor number of corpora lutea in females, when cc animals were compared with cn ones (p0,05). lc was modiffied as correlated response to the weight selection, but the presence of animales with tail malformations would be due to mutations that may be associated with fertility.
Page 1 /30
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.