We introduce the Green's functions technique as an alternative theory to the quantum regression theorem formalism for calculating the two-time correlation functions in open quantum systems at the steady state. In order to investigate the potential of this theoret-ical approach, we consider a dissipative system composed of a single quantum dot inside a semiconductor cavity and the emission spectrum is computed due to the quantum dot as well as the cavity. We propose an algorithm based on the Green's functions technique for computing the emission spectrum that can easily be adapted to more complex open quantum systems. We found that the numerical results based on the Green's functions technique are in perfect agreement with the quantum regression theorem formalism. More-over, it allows overcoming the inherent theoretical difficulties associated with the direct application of the quantum regression theorem in open quantum systems.

O presente estudo objetivou avaliar o efeito do genótipo do carneiro (Dorper ou Southdown), do sexo e do tipo de parto sobre características de crescimento de 268 cordeiros filhos de ovelhas Merino Australiano. Até o desmame, todos os animais permaneceram sobre pastagem de trevo-vermelho (Trifolium pratense ), chicória (Cychorium intibus ), trevo-branco (Trifolium repens ), festuca (Festuca arundinacea ) e azevém (Lolium multiflorum ), com carga animal de 10 ovelhas com seus cordeiros/ha. A partir do desmame (29,95±4,94kg de peso vivo e 109,45±7,41 dias de idade), os cordeiros permaneceram sobre a mesma pastagem utilizada durante a lactação, sendo terminados posteriormente sobre um cultivo de soja (Glycine max) , com carga animal de 30 cordeiros/ha. Não foi verificado efeito do genótipo do carneiro (P>0,05) sobre nenhuma das variáveis analisadas. Por outro lado, do nascimento ao desmame e do desmame até o embarque dos cordeiros para abate, os machos (criptorquidas) apresentaram ganhos de peso diário superiores (241 e 212g/dia; 121 e 94g/dia, para machos e fêmeas, respectivamente; P≤0,001), o que proporcionou um peso vivo ao embarque 14,9% superior em relação às fêmeas (40,89 e 35,59kg, para machos e fêmeas, respectivamente; P≤0,001). Os cordeiros de parto simples apresentaram maiores (P≤0,001) pesos vivos e medidas corporais ao nascimento, bem como maior velocidade de crescimento até o desmame (239 e 214g/dia, parto simples e duplo, respectivamente; P≤0,001). Porém, após o desmame, os cordeiros de parto duplo apresentaram maior ganho de peso (98 e 117g/dia) (P≤0,05) e uma superioridade (P≤0,001) em quilogramas de cordeiros desmamados (26,80 e 49,61kg) ou embarcados (33,91 e 64,69kg) por ovelha parida. Independentemente do sexo e do tipo de parto, todos os cordeiros superaram as exigências de peso e condição corporal mínima requerida para comercialização de cordeiros pesados no Uruguai, na metade do tempo que em média ocorre com os genótipos tradicionais.

This study aimed to evaluate the effect of ram genotype (Dorper or Southdown), sex and birth type on the growth characteristics of 268 lambs from Australian Merino ewes. Until weaning all animals were kept on red clover pasture (Trifolium pretense), chicory (Cychorium intibus), white clover (Trifolium repens), fescue (Festuca arundinacea) and ryegrass (Lolium multiflorum), with a stocking rate of 10 sheep and their lambs/ha. From weaning (29.95±4.94kg of body weight and 109.45±7.41 day-old), the lambs remained on the same pasture which was used during lactation, being subsequently finished on a soybean culture (Glycine max), with a stocking rate of 30 lambs/ha. No effect of ram genotype (P>0.05) was verified on any of the variables. On the other hand, the males (criptorquidas) presented superior weight gain from birth to weaning and from weaning until shipment of lambs for slaughter, (241 and 212g/day; 121 and 94g/day, for males and females, respectively; P≤0.001), which provided a body weight at shipment 14.9% higher than the female (40.89 and 35.59kg, for males and females, respectively; P≤0.001). Lambs originated from simple delivery presented higher (P≤0.001) body weight and body measures at birth, and a higher growth rate until weaning (239 and 214g/day, simple and double delivery, respectively; P≤0.001). Therefore, after weaning, the lambs originated from double delivery presented higher weight gain (98 and 117g/day) (P≤0.05) and were superior (P≤0.001) in kilograms of weaned lambs (26.80 and 49.61kg) or shipped (33.91 and 64.69kg) per parity ewes. Regardless of the sex and birth type, all lambs overcame the weight and body conditions required for commercialization of heavy lambs in Uruguai in half the average time of traditional genotypes.

Foi estudado o desempenho reprodutivo de 482 ovelhas multíparas (3/4 Texel x 1/4 Corriedale: TXC, 1/2 Romney Marsh x 1/2 Corriedale: RMC, 3/4 Poll Dorset x 1/4 Corriedale: PDC, 1/2 Finnish Landrace x 1/2 Merino Australiano: FLMA e Merino Australiano puras: MA), as características do crescimento de 585 cordeiros provenientes de carneiros Dorper e ovelhas: TXC (n = 68); RMC (n = 64); PDC (n = 68); FLMA (n = 183) e MA (n = 202) e os quilogramas de carne de cordeiros produzidos/kg de ovelha colocadas em cobertura (como indicador de eficiência), pastoreando campo natural e pastagens cultivadas. As ovelhas FLMA e TXC apresentaram as maiores taxas de parição (167,89 e 174,36%, respectivamente) em relação às demais cruzas, as quais não diferiram entre si (121,43 e 125,49%, PDC e RMC, respectivamente; P>0,05), porém foram superiores as MA (88,99%), sendo esse resultado uma consequência da maior quantidade de cordeiros nascidos/ovelha parida, que influenciou mais do que sua maior taxa de fertilidade. O genótipo da ovelha também afetou (P<0,0001) o crescimento dos cordeiros até o momento da sua venda com 41,6 ±6,7kg aos 206±7,25 dias de idade. Os cordeiros filhos das ovelhas TXC, PDC e RMC apresentaram maiores ganhos de peso diário que os filhos de FLMA, e esses maiores do que os MA. No entanto, de todas as cruzas avaliadas, somente a FLMA foi mais eficiente que a MA.

ABSTRACT The reproductive performance of 482 multiparous ewes, with growth characteristics of 585 lambs from Dorper rams and ewes: 3/4 Texel x 1/4 Corriedale (TXC, n = 68); 1/2 Romney Marsh x 1/2 Corriedale (RMC, n = 64); 3/4 Poll Dorset x 1/4 Corriedale (PDC, n = 68); 1/2 Finnish Landrace x Australian Merino (FLAM, n = 183) and Australian Merino pure ewes (AM, n = 202) and kg of lamb produced/kg of sheep used in the service (as an indicator of efficiency), grazing natural and sown pastures, were studied. The TXC and FLAM sheep had the highest lambing percentage (167.89 and 174.36%, respectively) compared to the rest of the other crosses, and did not differ from each other (121.43 and 125.49%, PDC and RMC respectively, P>0.05), but were higher than AM (88.99%), due to the greater number of lambs born / ewe calving rather than their higher fertility. The type of ewe also affected (P<0.0001) lamb growth until its sale at 41.6±6.7 kg to 206±7.25 days of age, showing mothers of TXC lambs, PDC and RMC had higher daily gains than the FLAM and these more than those of MA. However, in all crosses tested, only FLAM was more efficient than MA.

AbstractChlorella vulgaris and Scenedesmus obliquuswere grown in artificial-wastewater using a new nitrogen-limitation strategy aimed at increasing lipid productivity. This strategy consisted in a multi-stage process with sequential reduction of N-NH4 concentration (from 90 to 60, 40, and 20 mg.L-1) to promote a balance between cell growth and lipid accumulation. Lipid productivity was compared against a reference process consisting of nitrogen reduction in two stages, where the nitrogen concentration was suddenly reduced from 90 mg.L-1 to three different concentrations (10, 20, and 30 mg.L-1). In the multi-stage mode, only C. vulgaris exhibited a net lipid-productivity increase. Lipid content of S. obliquus did not present a significant increase, thus decreasing lipid productivity. The highest lipid productivities were observed in the two-stage mode for both S. obliquus and C. vulgaris (194.9 and 133.5 mg.L-1.d-1, respectively), and these values are among the highest reported in the literature to date.

Resumen Se estudió el efecto del peso al destete (bajo: 20, medio: 25 y alto: 28 kg) y del genotipo (cruza Southdown vs. cruza Dorper) sobre la velocidad de crecimiento, peso al sacrificio y estado corporal de 60 corderos. El experimento se realizó en verano por 119 días y los corderos tuvieron acceso restringido a una pradera de Trifolium pratenses y Cichorium intybus. El horario de pastoreo fue desde las 19:00 hasta las 07:00horas. El resto del tiempo, los corderos permanecieron en un encierro donde recibieron grano entero de sorgo (primeros 48 días) y sorgo + pellet de soja en una relación 60:40 (últimos 71 días), ofreciéndolo grupalmente al 1% del peso vivo ajustado semanalmente. La carga animal durante los 119 días experimentales fue de 20 corderos/ha. Debido a que los pesos vivos efectivos al principio del experimento resultaron mayores (p≤0,0001) a los pre-establecidos para el destete (23,4 kg, 26, 0 kg y 28,4 kg, bajo, medio y alto peso al destete, respectivamente), no se registraron diferencias entre ninguno de estos grupos en la ganancia diaria durante el período experimental y tampoco en su resultado económico. A diferencia del peso al destete, el genotipo utilizado tuvo respuesta biológica y económica. Los corderos cruza Southdown mostraron un mejor (p≤0,01) comportamiento biológico: + 25 g/día/cordero y económico: + US$ 3,8/cordero, durante el período experimental, frente a sus contemporáneos Dorper. El genotipo a utilizar en cruzamientos terminales es relevante si el cordero se comercializa a pesos elevados (≥ 34 kg).

Summary The effect of weaning weight (low: 20; average: 25 and high: 28 kg) and the genotype (cross Southdown or cross Dorper) on growth rate, slaughter weight and body condition was studied in 60 lambs. The experiment was conducted in summer during 119 days and the lambs had restricted access to a pasture of Trifolium pratenses and Cichorium intybus. The grazing time was from 19:00 until 07:00 hours. The rest of the time, the lambs remained confined and received whole sorghum grain as supplement (first 48 days) and sorghum + soybean pellets in a 60:40 rate (last 71 days), that was offered to all animals at 1% of the body weight, adjusted weekly. The stocking rate during the 119 experimental days was 20 lambs/ha. Since the live weights effective at the beginning of the experiment were greater (p≤0.0001) than those established for weaning (23.4 kg, 26.0 kg and 28.4 kg, low, average and high weaning weight, respectively), no significant difference was observed between groups regarding daily weight gain during the experiment or economical result. Unlike the weaning weight, the genotype used had biological and economical response. Southdown lambs presented better (p≤0.01) biological behavior: + 25 g/day/lamb and better economical result: + US$ 3.8/lamb, during the experimental period, once they were compared to their Dorper contemporaries. The genotype used for terminal crosses is relevant if the lambs are marketed with high weights (≥ 34 kg).

The objective of this work was to evaluate the morphoagronomic characteristics and the protein percentage of two genotypes: blue (BG) and white (WG), of the forage legume butterfly pea (Clitoria ternatea), cultivated on a trellis system, in Venezuela. Thirty-eight morphological and growth characteristics were evaluated, with a completely randomized experimental design. At 15 days of age the plants showed equal main stem length, number of nodes (Nn), number of leaves in the main stem (NLMS) and number of leaves in the plant, indicators which increased with age. Nn had a similar performance as NLMS and the vegetative stage lasted 30 days, when the first-order lateral branches developed and after 45 days the second-order branches developed. Pentafoliolate leaf shooting indicated the onset of flowering. Both genotypes showed a similar performance in the development stages: vegetative, flowering and production. BG showed higher vigor, high branching capacity and maximum values in leaf width and flower length, and WG had high pod and seed production; these characteristics constitute important morphological indicators in both genotypes. BG showed a higher content of CP (32,05%) at 90 days of age. To use this herbaceous legume as short-term protein source, because of its fast growth and high dry matter (89,48-90,35%) and CP (32,05-29,50%) contents is recommended; as well as to conduct other studies related to the management of this crop.

El objetivo de este trabajo fue evaluar las características morfoagronómicas y el porcentaje de proteína de dos genotipos: azul (GA) y blanco (GB), de la leguminosa forrajera zapatico de la reina (Clitoria ternatea), cultivados en un sistema de espalderas, en Venezuela. Se evaluaron 38 características morfológicas y de crecimiento, con un diseño experimental completamente aleatorizado. A los 15 días de edad las plantas mostraron igual longitud del tallo principal, número de nudos (Nn), número de hojas en el tallo principal (NHTP) y número de hojas en la planta, indicadores que se incrementaron con la edad. El Nn tuvo un comportamiento similar al NHTP y la fase vegetativa duró 30 días, cuando se desarrollaron las ramas laterales de primer orden, y a los 45 días lo hicieron las ramas de segundo orden. La emisión de hojas pentafolioladas indicó el inicio de la floración. Los dos genotipos presentaron un comportamiento semejante en las fases de desarrollo: vegetativa, floración y producción. El GA se caracterizó por su mayor vigor, alta capacidad de ramificación y valores máximos en el ancho de la hoja y la longitud de la flor, y el GB por su alta producción de legumbres y semillas; estas características constituyen importantes indicadores morfológicos en ambos genotipos. El GA presentó un mayor contenido de PC (32,05%) a los 90 días de edad. Se recomienda emplear esta leguminosa herbácea como fuente proteínica a corto plazo, por su rápido crecimiento y sus altos contenidos de materia seca (89,48-90,35%) y PC (32,05-29,50%); así como realizar otros estudios relacionados con la fitotecnia y manejo de este cultivo.

The objective of the study was to define a typology of integrated food and energy production systems with agroecological approach, in Cuba. The results are based on a preliminary evaluation of the performance of integrated farms belonging to the international project Biomas-Cuba. A methodology is described which can be helpful as basis for future evaluations of the diversity-efficiency-energy-productivity relationship, in the search for typologies that can characterize, as accurately as possible, such integrated systems. The methodology allowed quantifying the performance of diversity, energy efficiency and productivity of 25 production systems in different conversion stages and distributed in the western, central and eastern regions of Cuba. The evaluated indicators (previously validated in Cuba for this type of study) and the use of empirical calculation and multivariate statistical methods allowed identifying and characterizing three main types of integrated systems, which were termed BIOMAS-1A, BIOMAS-1B and BIOMAS-1C. The results of the indicators, as well as the analysis of similarities and differences among the different types constitute elements to be taken into consideration for further studies on integrated food and energy systems with a higher number of farms.

La investigación tuvo el objetivo de definir una tipología de sistemas integrados de producción de alimentos y energía con enfoque agroecológico, en Cuba. Los resultados se basan en una evaluación preliminar del comportamiento de fincas integradas pertenecientes al proyecto internacional Biomas-Cuba. Se describe una metodología que puede servir como base para futuras evaluaciones de la relación diversidad-eficiencia energética-productividad, en la búsqueda de tipologías que sirvan para caracterizar, de la manera más precisa posible, dichos sistemas integrados. La metodología permitió la cuantificación del comportamiento de la diversidad, la eficiencia energética y la productividad de 25 sistemas de producción en diferentes estadios de conversión y distribuidos en la zona occidental, la central y la oriental de Cuba. Los indicadores evaluados (previamente validados en Cuba para este tipo de estudio) y el uso de métodos de cálculo empírico y estadística multivariada permitieron identificar y caracterizar tres tipos fundamentales de sistemas integrados, a los cuales se les denominó BIOMAS-1A, BIOMAS-1B y BIOMAS-1C. Los resultados de los indicadores, así como el análisis de las semejanzas y diferencias entre los diferentes tipos constituyen elementos a tener en cuenta para posteriores estudios en sistemas integrados de alimentos y energía con un mayor número de fincas.

This paper provides experiences of the international project BIOMAS-CUBA in the implementation of energy supply alternatives from biomass in rural areas, which are compatible to food security and environmental sustainability. These experiences are comprised between 2009 and 2011, within the agroenergetic farm concept, and are related to research and technological innovation processes associated to: the morphological, productive and chemical evaluation of germplasm of non-edible oil plants with potential to produce biodiesel, ethanol and other products; the planting and agricultural management of associations of Jatropha curcas and 21 food crops; the cleaning and oil extraction of Jatropha seeds; the physical-chemical characterization of such oil; the production of biodiesel and its co-products; the biogas production from excreta and bioproducts and biofertilizers, with the effluents of biodigesters; the gasification of ligneous biomass to generate electricity; the characterization and classification of integrated food and energy production systems. Likewise, the socioeconomic and environmental studies allowed appreciating adequate economic-financial feasibility, remarkable increases in food production, the formation of human capital and the improvement of the people's quality of life, a positive environmental impact and a substitution of energy porters and conventional fertilizers.

El artículo brinda experiencias del proyecto internacional BIOMAS-CUBA en la implementación de alternativas de suministro de energía a partir de la biomasa en el medio rural, que sean compatibles con la seguridad alimentaria y la sostenibilidad ambiental. Estas experiencias se enmarcan entre 2009 y 2011, en el marco del concepto de la finca agroenergética, y están relacionadas con procesos de investigación e innovación tecnológica asociados a: la evaluación morfológica, productiva y química de germoplasma de plantas oleaginosas no comestibles con potencial para producir biodiesel, etanol y otros productos; la siembra y manejo agrícola de asociaciones de Jatropha curcas y 21 cultivos alimenticios; el beneficio y extracción de aceite de semillas de Jatropha; la caracterización físico-química de dicho aceite; la producción de biodiesel y sus coproductos; la producción de biogás a partir de excretas y de bioproductos y bioabonos, con los efluentes de biodigestores; la gasificación de biomasa leñosa para generar electricidad; la caracterización y clasificación de sistemas integrados para la producción de alimentos y energía. Asimismo, los estudios socioeconómicos y ambientales permitieron apreciar una adecuada factibilidad económico-financiera, incrementos notables en la producción de alimentos, la formación del capital humano y la mejora de la calidad de vida de las personas, un positivo impacto ambiental, y una sustitución de portadores energéticos y fertilizantes convencionales.

El tipo y número de bacterias en leche a nivel de finca está asociado a condiciones de manejo higiénico sanitario de las unidades de producción y sanidad de los animales, afectando su calidad microbiológica. Con el objetivo de estudiar la calidad bacteriológica de leche cruda de cabra, producida en la parroquia Faría, municipio Miranda del estado Zulia, se recolectaron 100 muestras a nivel de pezón, de 50 animales pertenecientes a 10 unidades de producción, y 10 correspondientes al pool de cada unidad. En leche de pezón se identificaron las bacterias presentes por pruebas bioquímicas. En el pool se determinaron contajes de aerobios mesófilos (AM), coliformes totales (CT), psicrófilos (PS), termófilos (TER) y termodúricos (TED) por los métodos de la APHA, también en estas muestras se identificaron con pruebas bioquímicas los coliformes presentes. Los géneros aislados de pezón fueron: Staphylococcus sp (54,84%) (St. coagulasa negativa (32,26%) y St. aureus (22,58%)), Streptococcus (22,58%) (Streptococcus spp (19,35%) y Str. agalactiae (3,23%)), Micrococcus (16,13%) y Pseudomonas (6,45%). Los recuentos promedios en el pool fueron: 1,8x10(7), 8,3x10(5), 2,5x10³, 1,8x10(4) y 1,1x10(4) (ufc.mL-1) para AM, CT, PS, TER y TED, respectivamente. Los coliformes encontrados fueron: E. coli (40%), Enterobacter sakazakii (25%), Citrobacter spp. (20%), Enterobacter spp. (10%) y Klebsiela (5%). Se concluye que en la leche de cabra producida en la parroquia Faría, predominan especies asociadas a infección intramamaria, y elevados recuentos bacterianos, que evidencian una baja calidad bacteriológica de la leche, representando su uso en la elaboración de queso blanco fresco, a partir de la leche cruda, un riesgo para la salud pública.

Type and number of bacteria in milk at farm level is associated with sanitary management conditions of both, farm and animals which affects its microbiological quality. With the objective of studying the bacteriological qualiy of raw goat milk produced in the Faria civil parish, Miranda Municipality of Zulia State, 100 milk samples were collected directly from both nipples of 50 goats belonging to 10 farms and 10 samples from the milk pool of each of such farms. In the nipple samples bacteria were identified by biochemical tests while in the pool samples counts of Mesophilic Aerobic (MA), Total Coliform (TC), Psychrophilic (PS), Thermophilic (TER) and Thermoduric (TED) bacteria were performed according to APHA methods. Coliforms in these pool samples were also identified by biochemical tests. Bacteria genus aisolated from nipples were: Staphylococci sp. 54.84% from which 32.26% were coagulase negative and 22.58% St. aureus, Streptococcus 22.58% from which 19.35% were Streptococcus sp. and 3.23% were Str. agalactiae, Micrococcus 16.13% and Pseudomonas 6.45%. Average pool sample counts were: 1.8x10(7), 8.3x10(5), 2.5x10³, 1.8x10(4) and 1.1x10(4) (ufc.mL-1) for MA, TC, PS, TER and TED respectively. Coliforms found were: E. coli 40%, Enterobacter sakazakii 25%, Citrobacter spp. 20%, Enterobacter spp.10% and Klebsiella 5%.From these results we concluded that in the milk of the farms tested, representatives of the Faria civil parish predominates bacteria species associated with intramammary infections. Elevated bacteria counts evidence a low bacteriological quality of this goat milk therefore making its use for raw milk fresh cheesemaking unsafe and risky for public health.

Phytoestrogens are plant-derived compounds having similar effects to estrogens. Several phytostrogen groups have been identified being the most characteristics the isoflavones like genistein, coumestans like coumestrol, and lignans represented by the enterolactone. Depending on the doses, they can act as agonists or antagonists of steroidal hormones. This apparently bimodal function is due to their capacity to interact with the alpha form of the estrogen receptor (ERα) in several organs of the female reproductive tract and to the beta form ERβ present in prostate, testis, ovaries, limph nodes and brain regions. It has been observed that an increase in genistein or coumestrol induces an increase in haemorrhagic follicles, miscarriages, LH-FSH surge suppression and even estrogenic syndrome, whereas in males, induces alterations in testis development and a decrease in sperm count. In this review, a panoramic view of the actual research of phytostrogen impact on the reproductive function and perspectives mainly for domestic animals is presented

Los fitoestrógenos son substancias de origen vegetal con propiedades similares a los estrógenos. Se han identificado diferentes grupos de fitoestrógenos entre los que destacan las isoflavonas como la genisteina, los coumestanos como el coumestrol, y los lignanos representados por la enterolactona. Estos compuestos actúan como agonistas o como antagonistas de las hormonas esteroidales dependiendo de la dosis que se utilice. Esta acción aparentemente contradictoria se debe a su capacidad para unirse como ligandos a los receptores estrogénicos alfa (ERα) del útero, glándula mamaria, sistema cardiovascular y hueso, y con mayor afinidad a los receptores estrogénicos beta (ERβ) presentes en próstata, ovarios, testículos, tracto urinario, tejido linfoide y algunas regiones del cerebro como el hipotálamo. Se ha observado que a medida que se incrementa la dosis de genisteína y coumestrol, se inducen folículos hemorrágicos, abortos, síndrome estrogénico, y supresión de picos de hormona luteinizante (LH) en las hembras, mientras que en los machos se altera el desarrollo testicular y disminuye el recuento de espermatozoides. En esta revisión se presenta un panorama del estado actual de las investigaciones respecto a las implicaciones de los fitoestrógenos sobre la reproducción y sus perspectivas de estudio, poniendo énfasis en su importancia en los animales domésticos

Biopsies were taken at a depth of 4cm from the Gluteus medius muscle of 16 horses. The animals were 6 years old and had not been trained during 3 months before the study. The samples were analized by mATPase miofibrillar technique to determine the fibrillar composition by NADH-TR technique to determine the oxidative capacity of the fibres and immunohistochemistry to determine the fibre type. The histochemical study revealed an average fibrillar composition of 14, 39, 30 and 17 % for fibres typed I, IIA, IIX oxidative and IIX no oxidative and the inmunohistochemistry study showed 16, 35, 29 y 20% for fibres type I, IIA, IIX and IIA-IIX. The statistical analyses showed a good relationship between the histochemical and inmunohistochemical method in the determination of fiber types. The immunohistochemical method allows a good identification of the fiber in adult horses.

Se tomó una biopsia a cuatro centímetros de profundidad en el músculo Gluteus medius de 16 equinos. Los animales tenían una edad promedio de 6 años y durante 3 meses previo a la toma de la biopsia no habían realizado entrenamiento. Las muestras fueron analizadas por medio de la técnica mATPasa miofibrilar, NADH-TR e inmuno-histoquímica. Los porcentajes de fibras tipo I, IIA, IIB oxidativas y no oxidativas fueron de un 14, 39, 30 y 17%, respectivamente, para la técnica histoquímica y un 16, 35, 29 y 20% para las fibras tipo I , IIA, IIX y IIA+IIX para la técnica inmuno-histoquímica. El análisis estadístico demostró que no existen diferencias signifi-cativas entre ambas técnicas para la determinación de las fibras. Los resultados obtenidos permiten concluir que la inmunohistoquímica es una técnica que permite realizar una clasificación adecuada de la población fibrilar del músculo Gluteus medius en equinos adultos.

To evaluate anaerobic and aerobic metabolism of the Gluteus medius muscle, biopsies of 16 clinically healthy draught horses of both sexes, were obtained at 3, 6 and 9 cm of depth. Creatinekinase (CK), lactic dehydrogenase (LDH) and citrate synthase (CS) activities in inactive and in working animals doing agricultural work was determined. The muscle tissue was homogenised, sonicated and centrifuged. Then the enzymatic activities were determined in the supernatant. The results obtained indicated that CK specific activity did not change according to depth of sampling, LDH specific activity was lower at a depth of 9 cm in inactive equines and CS specific activity increased. All enzymatic activities increased significantly in working horses compared to inactive individuals. The draught horses doing agricultural work increased their muscular metabolism, principally their aerobic muscular metabolism, avoiding the glycogen storage and muscle fatigue

De 16 equinos mestizos de tiro, de ambos sexos, clínicamente sanos, se obtuvieron biopsias del músculo Gluteus medius a 3, 6 y 9 cm de profundidad, con el objetivo de evaluar su metabolismo anaeróbico y aeróbico, determinando las actividades de las enzimas creatinquinasa (CK), deshidrogenasa láctica (LDH) y citrato sintetasa (CS) en animales inactivos y trabajando en faenas agrícolas. El tejido muscular se homogeneizó, sonicó y centrifugó; posteriormente en el sobrenadante se determinaron las actividades enzimáticas en estudio. Los resultados obtenidos indican que la profundidad del tejido no afectó la actividad específica de CK, la actividad de LDH fue menor a 9 cm de profundidad en los equinos inactivos y la actividad de CS aumentó a mayor profundidad del tejido. Las actividades enzimáticas aumentaron por efecto del trabajo realizado por los animales. Estos resultados señalan que los equinos mestizos de tiro incrementan su metabolismo al realizar faenas agrícolas; sin embargo, utilizan preferentemente el metabolismo aeróbico, evitando el consumo de las reservas de glicógeno y la fatiga muscular