A. Islas

Effects of winter supplementation and antiparasite treatment on the productive performance of milk herd in the central-south region of Chile

During the winter of 1994, a survey of productive and reproductive parameters was undertaken in the south-central part of Chile (8th Region) on 71 cows provided by four small farms with low production (< 3000 l/year). A low food intake was recorded (8.6 +/- 0.2-12.4 +/- 0.2 kg DM/day) and, as a result, the cows calved with poor body condition score (1.9 +/- 0.04 points on the scale of one-to-five, had milk production between 10.5 +/- 0.4 and 12.8 +/- 0.6 l/day, had a delayed start of ovulatory activity (78.2 +/- 4.6 days) and an interval between calving and conception of 120.3 +/- 4.6 days. In addition, low levels of packed cell volume (PCV) and hemoglobin (HEM) were found, which were considered to be a combined effect of low feed ingestion and parastic infection by Fasciola hepatica. To improve the productive and reproductive parameters, treatments were undertaken in three of the four small farms; a parasiticide treatment was used against the F. hepatica at the beginning of the winter and the availability of forage was increased via the use of supplementary green oats. Spring crops were also cultivated: corn for silage and oats with peas to make hay. The antiparasite treatment and supplementation of forage was associated with better body condition score at calving, improved hematological parameters, increased milk production (17%), reduced number of days to conception (120 vs. 91) and increased conception rate at first service (36 vs. 60%). In the fourth small farm where no interventions were undertaken, the parameters obtained during 1994 remained unchanged.

Características metabólicas del músculoGluteus medius de equinos mestizos con aptitud de tiro

De 16 equinos mestizos de tiro, de ambos sexos, clinicamente sanos, se obtuvieron biopsias del musculo Gluteus medius a 3, 6 y 9 cm de profundidad, con el objetivo de evaluar su metabolismo anaerobico y aerobico, determinando las actividades de las enzimas creatinquinasa (CK), deshidrogenasa lactica (LDH) y citrato sintetasa (CS) en animales inactivos y trabajando en faenas agricolas. El tejido muscular se homogeneizo, sonico y centrifugo; posteriormente en el sobrenadante se determinaron las actividades enzimaticas en estudio. Los resultados obtenidos indican que la profundidad del tejido no afecto la actividad especifica de CK, la actividad de LDH fue menor a 9 cm de profundidad en los equinos inactivos y la actividad de CS aumento a mayor profundidad del tejido. Las actividades enzimaticas aumentaron por efecto del trabajo realizado por los animales. Estos resultados senalan que los equinos mestizos de tiro incrementan su metabolismo al realizar faenas agricolas; sin embargo, utilizan preferentemente el metabolismo aerobico, evitando el consumo de las reservas de glicogeno y la fatiga muscular

Infection dynamics and acute phase response of an Actinobacillus pleuropneumoniae field isolate of moderate virulence in pigs

Actinobacillus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP), causes significant economic losses associated mainly with growth stunting of animals. Although serotypes can be distinguished according to their virulence, most of the studies are focused in A. pleuropneumoniae infections with virulent serotypes. There is little information regarding the role of acute phase proteins (APPs) and proinflammatory cytokines in infections with isolates of mild or moderate virulence. Thus, the present study aims to evaluate the kinetics of infection with an A. pleuropneumoniae serotype 6 (Ap6) field isolate of moderate virulence and the changes in the serum concentration of specific antibodies and different APPs and proinflammatory cytokines. Control animals showed no clinical signs or lesions throughout the study. Infected animals showed increased rectal temperature, respiratory distress and depression from 24hpi, and typical gross and microscopic lesions of PCP from 6hpi onwards. Ap6 was isolated from nasal swabs of four out of five inoculated animals at 24hpi, and from nasal swabs, tonsil and lung samples from all inoculated animals at 72hpi. Specific antibodies against Ap6 or changes in the serum concentration of IL-1β, IL-10 and TNF-α were not detected throughout the study. The serum concentration of IL-6 increased from 6hpi as well as serum A amyloid, C-reactive protein and haptoglobin from 24hpi onwards. Our results highlight the onset of the acute phase response after the infection with a field isolate of A. pleuropneumoniae of moderate virulence from 24hpi onwards which may be of interest in the study of the pathogenesis of this disease.

Características hematológicas y patológicas de cerdos inoculados experimentalmente con el aislado chileno del virus síndrome respiratorio y reproductivo porcino

The aims of this study were to characterize the haematological and bone marrow changes, gross and microscopic lesions of pigs experimentally inoculated with ...

Detección inmunohistoquímica del antígeno del virus del síndrome respiratorio y reproductivo (vPRRS) en cerdos inoculados

SUMMARY Porcine Reproductive and Respiratory Syndrome (PRRS), is a viral disease of swine that has been known in the United States since the 1980’s. The sickness was initially characterized by rapid propagation through pork farms, spreading through almost all the United States and later Canada and European countries. In Chile, PRRS was diagnosed at the end of 1999 and is currently part of an eradication program. To contribute to the diagnosis of the disease in our environment and to characterize the distribution of the viral antigen in the tissues of inoculated pigs, using an immunohistochemical (IHC) study was carried out utilizing 12 hybrid pigs originated from a PRSS free genetic pyramid. Nine were inoculated with the national isolate of the PRRS virus and three were used as controls. The inoculated pigs received an intranasal dosage of 7.0 ml of viremic serum from inoculated pigs with a cellular culture dose of 10 5.4 TCID 50 in order to reactivate its pathogenicity; they were also inoculated intramuscularly with 0.7 ml of the same serum. The pigs of the control group were sacrificed at 0 dpi and the inoculated pigs at 7, 14 and 21 dpi, At necropsy time, tonsils, retropharyngeal and mediastinal lymphatic nodes, thymus, spleen, nasal turbinates, lung, heart and liver were dissected, fixed, dehydrated and paraffin embedded. Additionally, lung alveolar macrophages were collected via a bronchoalveolar lavage. All these samples were immunostained using the monoclonal antibody SDOW-17 and the ABC complex method. Viral antigen was detected in the macrophages of all the tissues studied from 7 to 21 dpi. The organs that showed greatest intensity of reaction were the lungs and spleen. The consistent finding of greater quantity viral antigen of in these organs, these tissues suggest constitute the best source of samples for diagnosing the disease whether by IHC or other methods that detect the viral antigen or its genome.

Muscle fibre characteristics, enzyme activity and meat colour of wild boar (Sus scrofa s. L.) muscle with 2n=36 compared to those of phenotypically similar crossbreeds (2n=37 and 2n=38).

The aim of the present study was to evaluate European wild boar (Sus scrofa s. L.) of chromosomal number 2n=36 in comparison with phenotypically similar crossbreeds (2n=37 and 2n=38) with respect to the muscle fibre characteristics and enzyme activity as well as meat colour in the longissimus dorsi (LD) and semimembranosus (SM) muscles. Differences in the proportion of IIA fibre in the LD muscle between karyotypes 2n=37 and 2n=38 were found. The 2n=36 group showed a lower muscle fibre cross-section area than the 2n=38 karyotype. The meat colour of the 2n=36 karyotype group was redder than 2n=37 and 2n=38. The muscle fibre cross-section area might explain the differences in colour of the meat of wild boar.

Estudios hematológicos y patológicos comparativos de cerdos inoculados con un aislado de campo y el serotipo 5 ATCC de Actinobacillus pleuropneumoniae

SUMMARY An experimental inoculation of Actinobacillus pleuropneumoniae (App) was carried out with a field isolate and an ATCC serotype 5. Three groups of 15 pigs each were used. Group 1 (G1) was the control group inoculated with sterile media, Group 2 was inoculated with the serotype 5 ATCC, and Group 3 (G3) was inoculated with a field isolate (418/07). The results showed statistically significant differences (P ≤ 0.05) in the total leukocytes count between G1 v/s G2 and G1 v/s G3. The total macroscopic lung lesions scores were statistically different among the 3 groups (P ≤ 0.05). However, statistical difference was found only between G1 and G3 in the histopathological lung lesions (P ≤ 0.05). This work shows a clear difference in the hematological changes and the macroscopic and histopathological lesions between the serotype 5 ATCC and the field isolate. These facts suggest a higher virulence and pathogenicity of the national isolate. The serotypification of this App national isolate will be done in the near future.

Características histoquímicas y morfométricas del músculo Gluteusmedius en equinos en preparación para competencias de salto.: Estudio preliminar

Se obtuvieron biopsias a 3 y 6 centimetros de profundidad del musculo de 7 yeguas y 3 machos castrados de 3 a 4 anos de edad, los cuales no habian realizado con anterioridad ningun programa especifico de entrenamiento por 3 meses.Las muestras fueron analizadas por las tecnicas mATPasa miofibrilar, para determinar la composicion fibrilar, y NADH-TR para determinar la capacidad oxidativa. Los promedios obtenidos para la composicion fibrilar fueron de 21.6%, 36.2%, 26.9% y 15.3% para las fibras tipo I, IIA, IIB oxidativas y IIB no oxidativas, respectivamente. La composicion fibrilar varia en relacion con la profundidad de la biopsia. Las fibras tipo I y IIB presentan diferencias significativas entre los3 y 6 cm. Las fibras tipo IIB no varian con la profundidad de la biopsia. Los equinos en periodo de descanso presentan una alta proporcion de fibras tipo IIB. Las fibras tipo IIB oxidativas y no oxidativas no variaron su porcentaje entre las biopsias. El area de las fibras musculares fueron 2.335, 3.194 y 5.166 µm2 para las fibras tipo I, IIA y IIB respectivamente y el diametro menor fue 19, 23 y 28 para las fibras tipo I, IIA y IIB. Los resultados obtenidos indicanque la composicion fibrilar del musculo Gluteus medius en equinos de salto fue diferente a otras razas estudiadas.

Haematological and blood biochemical changes induced by the administration of low doses of Escherichia coli lipopolysaccharide in rabbits

El objetivo fue investigar los cambios hematologicos y en la bioquimica sanguinea inducidos por la administracion de dosis bajas de lipopolisacarido de Escherichia coli (LPS) en conejos. Seis conejos clinicamente sanos fueron distribuidos en dos grupos experimentales mediante un diseno cruzado: Grupo 1 (LPS) tratado con dos dosis intravenosas de 1 μg/kg de LPS. Grupo 2 (Control) fue tratado con un volumen equivalente de solucion salina (SS). Previo y posterior a la administracion de LPS se midio temperatura rectal (°C), se determinaron las concentraciones de interleukina 6 (IL-6), proteina C reactiva (PCR), ademas se realizo hemograma y se midio la actividad de las enzimas aspartato aminotransferasa (AST) y gamma glutamil transferasa (GGT). La administracion de LPS produjo aumentos significativos en la temperatura rectal, IL-6 y PCR. A las 4 y 8 h posteriores a la inyeccion de LPS se observo leucopenia asociada a disminucion en el recuento de monocitos, linfocitos y plaquetas, mientras que a las 12 y 24 h el recuento de leucocitos y neutrofilos aumento significativamente. No se observaron cambios en los promedios de VGA, concentracion de proteinas totales y albumina o en la actividad de las enzimas AST y GGT. Se concluye que las modificaciones hematologicas y de bioquimica sanguinea inducidas por la administracion de dosis bajas de LPS son de moderada intensidad y corta duracion en comparacion a las descritas en conejos tratados con dosis altas de LPS. Estos cambios son consistentes con un estado de respuesta inflamatoria inicial inducida por una infeccion por Gram negativos

HEMATOLOGIC AND BIOCHEMICAL PARAMETERS OF KELP GULLS (LARUS DOMINICANUS) CAPTURED IN THE CITY OF TALCAHUANO, CHILE

Abstract:  In order to provide tools for future health-based monitoring programs, we developed reference intervals for hematology and plasma biochemistry and partitioned data for sex and season (winter and autumn). Ninety-one physically healthy kelp gulls (Larus dominicanus) were sampled in the city of Talcahuano, Chile, during winter (July–September) of 2007, autumn (April–June) and winter of 2008, and autumn of 2009. After blood sampling, the kelp gulls were euthanized by cervical dislocation. Packed cell volume (PCV), hemoglobin, total plasma protein (TPP), and complete blood count were performed. Alanine amino transferase, gamma-glutamyl transpeptidase, lactate dehydrogenase, alkaline phosphatase (ALP), creatinine, urea, calcium, phosphorus, and uric acid were analyzed. No significant differences were found between sexes (P > 0.05). When a comparison was made between the two seasons, the values of PCV, TPP, white blood cell, heterophils, eosinophils, and monocytes were significantly higher in winter than in autumn (P < 0.05) while and urea and uric acid concentrations were higher in autumn. Heterophils were the predominant circulating leukocyte for all birds. There was no significant difference in body condition between autumn and winter nor between sexes. Body condition showed a significant relationship with TPP and basophil concentration and ALP activity.