The objective of this study was to evaluate the effect of the protein source in sugarcane silage-based diets on the ruminal pH and in situ dry matter digestibility (DMD). The treatments were: 1)- 60% sugarcane silage + 15% soybean meal (SBM); 2)- 60% sugarcane silage + 15% fish meal (FM); 3)- 55% sugarcane silage + 20% canola meal (CM); and T4)- 50% sugarcane silage + 30% coconut meal (CCM). In situ DMD was determined by the nylon bag technique using four cows equipped with ruminal cannula. Five grams of each experimental diet were weighted in nylon bags and incubated for 8, 12, 24, 48, 72 and 96 h. Dry matter digestibility for SBM, CM, and CCM showed higher values compared to FM. A similar pH among treatments was recorded; however, at 4 h decreases in SBM and FM were observed. Sugarcane silage in integral diets with the different protein sources used in this study, did not modify ruminal pH but showed lower DMD when fish meal was the protein source.

El objetivo de este estudio fue evaluar el efecto de la fuente proteica de dietas a base de ensilado de caña de azúcar sobre el pH ruminal y la digestibilidad in situ de la materia seca (DMD). Los tratamientos fueron: 1)- 60% de ensilado de caña de azúcar + 15% harina de soya (SBM); 2)- 60% ensilado de caña de azúcar + 15% harina de pescado (FM); 3)- 55% ensilado de caña de azúcar + 20% harina de canola (CM); y 4)- 50% de ensilado de caña de azúcar + 30% de harina de coco (CCM). La DMD se determinó mediante la técnica de bolsa de nylon utilizando cuatro vacas equipadas con cánula ruminal. Se pesaron cinco gramos de cada dieta experimental y se incubaron en bolsas de nylon por 8, 12, 24, 48, 72 y 96 h. La digestibilidad de la materia seca para SBM, CM y CCM mostraron los valores más altos en comparación con FM. No hubo cambios en el pH ruminal en los tratamientos, pero, a las 4 h disminuyó en SBM y FM. El ensilado de caña de azúcar en dietas integrales con las diferentes fuentes de proteínas no modifica el pH ruminal, pero reduce la DMD cuando la harina de pescado es la fuente de proteína.

ABSTRACT The objective of the study was to evaluate the productive response of lactating calves fed with initiator with added Saccharomyces cerevisiae yeast culture (YC). Ten male and six female calves, aged between five and 27 days, were randomly assigned to two treatments: T1) starter feed and T2) starter feed plus YC used in a completely randomized experimental design with eight replicates per treatment. They were under continuous grazing on Estrella (Cynodon plectostachyus) and Guinea (Megathyrzus maximum) grass pastures, plus starter on free access. From day 135 onwards, two kg of growth feed per calf were supplied. The variables evaluated were daily weight gain (DWG), live weight change (LWC), starter feed intake (SI) and feed conversion (FC). There were no differences in the variables evaluated (p> 0.05) in both treatments. The results indicate that the productive response in lactating calves is similar to that of calves including yeast culture in their diet.

RESUMEN El objetivo del presente estudio fue evaluar la respuesta productiva de becerros lactantes alimentados con iniciador al cual se le adicionó cultivo de levaduras de Saccharomyces cerevisiae (CLSC). Diez becerros machos y seis hembras, con edades entre 5 y 27 días, se distribuyeron de manera aleatoria en dos tratamientos, T1: alimento iniciador y T2: alimento iniciador más CLSC bajo un diseño experimental completamente al azar, con ocho repeticiones por tratamiento. Estuvieron en pastoreo continuo en praderas de pasto Estrella (Cynodon plectostachyus) y Guinea (Megathyrzus maximum), más iniciador a libre acceso. Del día 135 en adelante se ofrecieron 2 kg de alimento de crecimiento por becerro. Las variables evaluadas fueron ganancia diaria de peso (GDP), cambio de peso vivo (CPV), consumo de alimento iniciador (CI) y conversión alimenticia (CA). No hubo diferencias en las variables evaluadas (p > 0.05) entre tratamientos. Los resultados obtenidos indican que la respuesta productiva en becerros lactantes es similar al incluir cultivo de levaduras en la dieta.

The values of biological parameters related to the life cycles of four populations of Meccus longipennis (Reduviidae: Triatominae) were evaluated. Cohorts of each of the four studied populations from different geographical areas of Mexico were maintained under similar laboratory conditions and then compared. The population from El Saucito de Araujo was different from the other three studied populations, which could help explain the secondary importance of M. longipennis in the state of Chihuahua. This paper also supports the proposition that biological traits are important criteria for determining relationships between populations.

The values of biological parameters related to hatching, lifespan, the number of blood meals between moults, mortality, time lapse before the beginning of feeding, feeding time and defecation delay for each instar of three Mexican-American species of Triatominae, Triatoma recurva, Triatoma protracta (former subspecies protracta) and Triatoma rubida (former subspecies uhleri), were evaluated and compared. No significant (p > 0.05) differences were recorded among the three species with respect to the average time required to hatch. This time was approximately 19 days. The average egg-to-adult development time was significantly (p < 0.05) shorter for T. rubida. The number of blood meals at each nymphal instar varied from one-five for each species. The mortality rates were higher for the first-instar nymphs of the three species studied. The mean time lapse before the beginning of feeding was between 0.3-3 min for most nymphs of all instars of each species studied. The mean feeding time was the longest for T. recurva, followed by T. protracta. The defecation delay was less than 10 min for T. recurva and T. rubida. Given these results, only T. rubida should be considered an important potential vector of Trypanosoma cruzi transmission to humans in areas of Mexico where these species exist, whereas T. recurva and T. protracta would be of secondary importance.

Se reporta por primera vez la recolecta de ejemplares de Meccus longipennis (Usinger) y de Triatoma recurva (Stål) en el estado de Durango. La búsqueda de triatominos se realizó durante 12 meses (septiembre 2010-agosto 2011) en cuatro comunidades de dos municipios (Pueblo Nuevo y Mezquital) del estado de Durango. Se recolectaron 71 ejemplares de M. longipennis y seis de T. recurva provenientes mayoritariamente del interior de las viviendas humanas (recámaras). La presencia de M. longipennis en el área abre la posibilidad de un riesgo potencial de transmisión de Trypanosoma cruzi Chagas a las poblaciones humanas del área estudiada.

The collection of Meccus longipennis (Usinger) and of Triatoma recurva (Stål) in the state of Durango is reported for the first time. Both species were collected during twelve months (from September 2010 to August 2011) in four localities of two municipalities (Pueblo Nuevo y Mezquital) in the state of Durango. Seventy one specimens of M. longipennis and six of T. recurva were collected mostly from indoors of human dwellings (bedrooms). Presence of M. longipennis means a potential risk of transmission of Trypanosoma cruzi Chagas to human populations in the study area.

An entomological study of triatomine species was carried out to assess their prevalence in 10 localities of the state of Michoacán, Mexico. Entomological indices were calculated to estimate the risk for vector-borne transmission of Trypanosoma cruzi to the human population in this area. Four triatomine species (Triatoma barberi, Triatoma dimidiata, Meccus pallidipennis and Meccus longipennis) were collected from the study area. This is the first report of M. longipennis and T. dimidiata in Michoacán. M. pallidipennis was significantly (p < 0.05) more abundant than any of the other species collected in the study area. Infection indices were greater than 50% for each of the four collected triatomine species. Significantly more triatomines were collected from intradomiciliary areas than from peridomiciliary or sylvatic areas. Infestation, crowding and density indices were low, whereas colonisation indices were high in five localities. The current vectorial conditions in the study area require continuous entomological and serological surveillance to diminish the risk of T. cruzi transmission to human populations.

Se midió el efecto en la composición química de la paja de trigo usada como sustrato en la producción de Pleurotus pulmonarius. Las pajas de trigo, tanto tratadas con P. pulmonarius como no tratadas, fueron obtenidas de una empresa comercial. Para obtener muestras representativas para el análisis químico se tomaron al azar diez bolsas de la paja usada como sustrato para cultivar el hongo. El grupo testigo consistió en las pajas esterilizadas sin tratamiento con P. pulmonarius. A todas las muestras se les determinó materia seca, materia orgánica, proteína cruda, fibra detergente neutro, fibra ácido detergente, celulosa y hemicelulosa. Los datos obtenidos fueron analizados mediante una comparación de medias utilizando una prueba de t-Student. No se encontraron diferencias (P>0,05) para el porcentaje de materia seca, proteína cruda y hemicelulosa; sin embargo, se presentó un mayor (P<0,05) porcentaje de materia orgánica, fibra detergente neutro y ácido para la paja tratada en comparación con la no tratada. Se concluye que el crecimiento del P. pulmonarius en paja de trigo mejora la composición química de las pajas aumentando el contenido de materia orgánica y modifica la estructura de la fibra, con lo que se incrementa el contenido de carbohidratos solubles.

The effect of Pleurotus pulmonarius on the chemical composition of wheat straw was evaluated. Wheat straw, treated and untreated with P. pulmonarius, was obtained from a commercial facility. Ten samples plastic bags of wheat straw used previously as substrate to culture edible fungus were collected at random. The negative control group consisted of the pasteurized wheat straw untreated with P. pulmonarius. All samples were analyzed to determine dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber, cellulose and hemicellulose of each wheat straw. Data were analyzed by mean comparison using a t-Student test. No differences (P>0.05) between treatments were found for dry matter, crude protein and hemicellulose; however, straw treated with P. pulmonarius showed higher percentages (P<0.05) of organic matter, neutral and acid detergent fiber. It is concluded that growing P. pulmonarius in wheat straw improves the chemical composition of the straw by increasing its organic matter content and modifies the fiber structure, which increases the soluble carbohydrates content.

Mede-se o efeito na composição química da palha de trigo usada como substrato na produção de Pleurotus pulmonarius. As palhas de trigo, tanto tratadas com P. pulmonarius como não tratadas, foram obtidas de uma empresa comercial. Para obter amostras representativas para a análise química se tomaram aleatoriamente dez sacolas da palha usada como substrato para cultivar o fungo. O grupo testemunha consistiu em palhas esterilizadas sem tratamento com P. pulmonarius. Determinou-se, em todas as amostras, matéria seca, matéria orgânica, proteína crua, fibra detergente neutro, fibra ácido detergente, celulose e hemicelulose. Os dados obtidos foram analisados mediante uma comparação de médias utilizando uma prova de t. Não se encontraram diferenças (P>0,05) para a porcentagem de matéria seca, proteína crua e hemicelulose; no entanto, se apresentou uma maior (P<0,05) porcentagem de matéria orgânica, fibra detergente neutra e ácida para a palha tratada em comparação com a não tratada. Conclui-se que o crescimento do P. pulmonarius na palha de trigo melhora a composição química das palhas aumentando o conteúdo de matéria orgânica e modifica a estrutura da fibra, com o que se incrementa o conteúdo de carboidratos solúveis.

Se realizó un estudio con el fin de observar el efecto de la adición de vitaminas hidrosolubles en la digestibilidad in vitro de la materia seca (DIVMS) y materia orgánica (DIVMO) en dietas con distinta fuente de carbohidratos (sorgo y cebada en grano), adicionadas con cinco dosis de vitaminas B (VB; 0, 2, 4, 6 y 8 g kg-1 MS). Se encontraron diferencias significativas (P < 0,01), tanto para los efectos principales (fuente de carbohidratos y cantidad de VB), como para la interacción de éstos, en ambos casos (DIVMS y DIVMO). Al adicionar dietas con 8 g y como fuente de carbohidratos el sorgo, la DIVMS y DIVMO aumentó, pero no cambió cuando la fuente de carbohidratos fue la cebada. La adición de vitaminas hidrosolubles a dietas con sorgo mejora la DIVMS y DIVMO, observándose que la naturaleza y calidad de la dieta puede influir en la producción de vitaminas hidrosolubles por los microorganismos ruminales

The objective of this study was to evaluate the effect of B vitamins on in vitro digestibility of dry matter (IVDMD) and organic matter (IVOMD) of diets with different source of carbohydrates (sorghum and barley grain), with five concentrations of B vitamins (BV; 0, 2, 4, 6 and 8 g kg-1 DM). There were differences (P < 0.01) for the principal effects (source of carbohydrates x concentration of BV), also for the interaction of them in both cases (IVDMD and IVOMD). At 8 g with sorghum increases the IVDMD and IVOMD, but did not change when the source of carbohydrates was the barley. The addition of B vitamins improves the IVDMD and IVOMD, also the nature and quality of the diet effect the microbial B vitamin production