Los carotenoides dietéticos en el organismo animal

Los compuestos carotenoides se encuentran en plantas, algas y bacterias, principalmente, y son ingeridos por los animales en sus dietas. Estos compuestos lipofílicos se dividen en carotenos y xantofilas, dependiendo de su estructura y composición molecular.  Además de su función como precursores de la vitamina A y como antioxidantes, los carotenoides también se pueden depositar en varios tejidos y órganos como el ojo, hígado, músculo, piel, picos y plumas de aves, en los cuales también cumplen funciones esenciales tanto fisiológicas como de comportamiento. Adicionalmente, se sugiere que puede haber una tasa de transferencia durante la reproducción, especialmente en animales ovíparos e insectos. Los carotenoides son, en su mayoría, los responsables de la coloración roja, anaranjada, amarilla o verde que puedan mostrar algunas especies de animales tales como crustáceos, peces, aves y reptiles. Las variaciones dietéticas pueden afectar la expresión de estos colores, por lo que la nutrición es clave en la dinámica de estos compuestos en el organismo animal

The interplay between voluntary food intake, dietary carbohydrate-lipid ratio and nutrient metabolism in an amphibian, (Xenopus laevis)

Digestion of food and metabolism of frogs are little studied at the moment, and such processes could be very particular in the case of amphibians, given their ectothermic and carnivorous nature which may lead them to use nutrients through specific biochemical pathways. In the present study, 24 adult Xenopus laevis (six replicates with two frogs per treatment) were randomly assigned to two diets with different carbohydrate:fat ratio (4.5:1 and 2.1:1), changing the dietary glucogenic and lipogenic proportions. Food intake (FI) per unit metabolic body weight (MBW) as well as macronutrient digestibility were calculated, and circulating blood acylcarnitines and amino acids measured, in order to evaluate the effect of the diet treatments. Results demonstrated that food intake regulated most of the changes in the parameters evaluated; significant differences were obtained in crude protein and fat digestibilities through the effect of FI/MBW (p<0.05), whereas diet treatment had a significant effect on the levels of malonyl-CoA. Food intake also significantly impacted malonyl, isovaleryl, hydroxyisovaleryl and long chain fatty acid concentrations; significant (p<0.05) interactions between those metabolites were detected owing to diet. The findings obtained suggest that food intake was the main factor controlling digestion and metabolism in X. laevis, with frogs preferring to utilise protein and fat as primary sources for energy production in the citric acid cycle, reflecting characteristics of a strict carnivore physiological model

Gaining insights in the nutritional metabolism of amphibians : analyzing body nutrient profiles of the African clawed frog, Xenopus laevis

Whole bodies of Xenopus laevis (n = 19) were analysed for chemical composition and morphometrics. The nutrient profile (macronutrients, amino acids, fatty acids and minerals) was evaluated by sex; interactions among variables with body weights and lengths, and comparisons made with different species of marine and fresh water fish. Significant differences were found in morphometric measurements, water content, several minerals and fatty acids between sexes of X. laevis. Amino acid profiles differed in methionine, proline and cysteine, which could underlie different metabolic pathways in frogs when compared to fish. In addition, fatty acid profiles revealed more monounsaturated and n - 6 polyunsaturated fatty acids in frogs than in fish, more similar to values reported for terrestrial than aquatic vertebrates. Important interactions were also found between body measurements and fat, calcium, and phosphorus, as well as between essential and non-essential amino acids. The results indicate that frogs might have particular biochemical pathways for several nutrients, dependent on sex and linked to body weight, which ultimately could reflect specific nutrient needs

Colouration in amphibians as a reflection of nutritional status : the case of tree frogs in Costa Rica

Colouration has been considered a cue for mating success in many species; ornaments in males often are related to carotenoid mobilization towards feathers and/or skin and can signal general health and nutrition status. However, there are several factors that can also link with status, such as physiological blood parameters and body condition, but there is not substantial evidence which supports the existence of these relationships and interactions in anurans. This study evaluated how body score and blood values interact with colouration in free-range Agalychnis callidryas and Agalychnis annae males. We found significant associations between body condition and plasmatic proteins and haematocrit, as well as between body condition and colour values from the chromaticity diagram. We also demonstrated that there is a significant relation between the glucose and plasmatic protein values that were reflected in the ventral colours of the animals, and haematocrit inversely affected most of those colour values. Significant differences were found between species as well as between populations of A. callidryas, suggesting that despite colour variation, there are also biochemical differences within animals from the same species located in different regions. These data provide information on underlying factors for colouration of male tree frogs in nature, provide insights about the dynamics of several nutrients in the amphibian model and how this could affect the reproductive output of the animals

Estudios actuales de literatura comparada. Teorías de la literatura y diálogos interdisciplinarios

Estos dos volúmenes constituyen una contribución al desarrollo de la comparatística que se realiza, principalmente, desde América Latina. El primer volumen está organizado en tres partes y consta de 22 artículos, mientras que el segundo reúne 24 capítulos.UCR::Vicerrectoría de Docencia::Artes y Letras::Facultad de Letras::Escuela de Filología, Lingüística y LiteraturaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Sistema de Educación General::Escuela de Estudios GeneralesUCR::Vicerrectoría de Investigación::Sistema de Estudios de Posgrado::Artes y Letras::Maestría Académica en Literatura FrancesaUCR::Vicerrectoría de Investigación::Sistema de Estudios de Posgrado::Artes y Letras::Maestría Académica en Literatura LatinoamericanaUCR::Vicerrectoría de Docencia::Artes y Letras::Facultad de Letras::Escuela de Lenguas Moderna

Respuesta productiva de conejos alimentados con follaje fresco de nacedero (Trichanthera gigantea, Lamiales:Acanthaceae)

Productive response of rabbits fed with fresh leaves of nacedero (Trichanthera gigantea, Lamiales:Acanthaceae). Rabbit production is a viable activity in Costa Rica. It offers consumers a high quality meat, and for farmers a good income with a relatively low investment. Production performance, including weight gain and dressing percentage of rabbits fed with two levels of fresh “nacedero” leaves (Trichanthera gigantea) were evaluated. The experiment was conducted in a commercial farm, using 30 weanling animals (California breed) randomly distributed among three treatments (ten animals per treatment): T1: Control: 100% commercial extruded diet, T2: 85:15, 85% commercial extruded diet and 15% nacedero fresh leaves, T3: 70:30, 70% commercial extruded diet and 30% nacedero fresh leaves. Animals were individually weighed weekly for eight weeks, then slaughtered at 88 days of age and dressing percentage calculated. Significant differences (p&lt;0,05) were found between animals from treatments 1 and 2 compared to treatment 3 according to Tukey test. Treatment 3 showed the lowest final weight (p=0,003), weight gain (p=0,008) and dressing percentage (p=0,002). Animals´ initial weights (included as a covariable) had an important effect in all parameter responses (p=0,02). Average initial weights were 441, 403 and 418 g; weight gain was 19, 19 and 17 g/animal/day and dressing percentage was 55, 54 and 51% for animals from treatments 1, 2 and 3 respectively. Dry matter intake was significantly less in animals from treatments 2 and 3 compared to control (p&lt;0,05). It is suggested that 15% of substitution of fresh nacedero foliage in diets for fattening rabbits did not affect productive performance; and improve the use of plants with high potential as forages in productive systems with small animal` species.La producción de carne de conejo es una alternativa viable en Costa Rica, ofreciendo al consumidor un producto de buena calidad, y a los productores posibilidad de aumentar sus ingresos. Se evaluaron los rendimientos productivos de conejos alimentados con nacedero fresco (Trichanthera gigantea) a través del peso de sacrificio, ganancia de peso y rendimiento en canal. El experimento se realizó en una finca comercial, y se utilizaron 30 conejos de la raza California, asignados al azar a tres tratamientos: T1: Control: 100% alimento balanceado comercial extrusado para conejos de engorde, T2: 85:15, 85% alimento balanceado y 15% de hojas frescas de nacedero, T3: 70:30, 70% alimento balanceado y 30% hojas frescas de nacedero. Los conejos se pesaron semanalmente durante ocho semanas, se sacrificaron a los 88 días de edad y se determinó su rendimiento en canal. Se encontraron diferencias significativas en el crecimiento de los animales de los tratamientos 1 y 2 con respecto al 3 por medio de la prueba de Tukey; así como las menores ganancias de peso (p=0,008) y rendimiento en canal (p=0,002). El peso inicial de los animales (incluido como covariable), ejerció un efecto significativo en la respuesta de todos los parámetros (p=0,02). Los pesos promedio iniciales fueron 441, 403 y 418 g, las ganancias de peso 19, 19 y 17 g/animal/día, y el rendimiento en canal 55, 54 y 51%  para los animales del tratamiento 1, 2 y 3 respectivamente. Se sugiere que un 15% de sustitución del alimento balanceado por follaje fresco de nacedero en dietas para conejos de engorde no afecta su respuesta productiva, e incentiva el uso de plantas con alto potencial forrajero en sistemas productivos de pequeñas especies

Seminario de producción pecuaria

Primera edición. Número de páginas: 336. Género: Didáctico Temática: AgroindustriaUna obra de apoyo para el docente y una guía para el estudiante de agroindustria sobre la obtención de los productos de origen animal, su situación actual y su marco legal, centrada en la producción de especies de interés zootécnico.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni

Respuesta productiva de conejos alimentados con follaje fresco de nacedero (Trichanthera gigantea, Lamiales:Acanthaceae)

Productive response of rabbits fed with fresh leaves of nacedero (Trichanthera gigantea, Lamiales:Acanthaceae). Rabbit production is a viable activity in Costa Rica. It offers consumers a high quality meat, and for farmers a good income with a relatively low investment. Production performance, including weight gain and dressing percentage of rabbits fed with two levels of fresh “nacedero” leaves (Trichanthera gigantea) were evaluated. The experiment was conducted in a commercial farm, using 30 weanling animals (California breed) randomly distributed among three treatments (ten animals per treatment): T1: Control: 100% commercial extruded diet, T2: 85:15, 85% commercial extruded diet and 15% nacedero fresh leaves, T3: 70:30, 70% commercial extruded diet and 30% nacedero fresh leaves. Animals were individually weighed weekly for eight weeks, then slaughtered at 88 days of age and dressing percentage calculated. Significant differences (p<0,05) were found between animals from treatments 1 and 2 compared to treatment 3 according to Tukey test. Treatment 3 showed the lowest final weight (p=0,003), weight gain (p=0,008) and dressing percentage (p=0,002). Animals´ initial weights (included as a covariable) had an important effect in all parameter responses (p=0,02). Average initial weights were 441, 403 and 418 g; weight gain was 19, 19 and 17 g/animal/day and dressing percentage was 55, 54 and 51% for animals from treatments 1, 2 and 3 respectively. Dry matter intake was significantly less in animals from treatments 2 and 3 compared to control (p<0,05). It is suggested that 15% of substitution of fresh nacedero foliage in diets for fattening rabbits did not affect productive performance; and improve the use of plants with high potential as forages in productive systems with small animal` species.La producción de carne de conejo es una alternativa viable en Costa Rica, ofreciendo al consumidor un producto de buena calidad, y a los productores posibilidad de aumentar sus ingresos. Se evaluaron los rendimientos productivos de conejos alimentados con nacedero fresco (Trichanthera gigantea) a través del peso de sacrificio, ganancia de peso y rendimiento en canal. El experimento se realizó en una finca comercial, y se utilizaron 30 conejos de la raza California, asignados al azar a tres tratamientos: T1: Control: 100% alimento balanceado comercial extrusado para conejos de engorde, T2: 85:15, 85% alimento balanceado y 15% de hojas frescas de nacedero, T3: 70:30, 70% alimento balanceado y 30% hojas frescas de nacedero. Los conejos se pesaron semanalmente durante ocho semanas, se sacrificaron a los 88 días de edad y se determinó su rendimiento en canal. Se encontraron diferencias significativas en el crecimiento de los animales de los tratamientos 1 y 2 con respecto al 3 por medio de la prueba de Tukey; así como las menores ganancias de peso (p=0,008) y rendimiento en canal (p=0,002). El peso inicial de los animales (incluido como covariable), ejerció un efecto significativo en la respuesta de todos los parámetros (p=0,02). Los pesos promedio iniciales fueron 441, 403 y 418 g, las ganancias de peso 19, 19 y 17 g/animal/día, y el rendimiento en canal 55, 54 y 51%  para los animales del tratamiento 1, 2 y 3 respectivamente. Se sugiere que un 15% de sustitución del alimento balanceado por follaje fresco de nacedero en dietas para conejos de engorde no afecta su respuesta productiva, e incentiva el uso de plantas con alto potencial forrajero en sistemas productivos de pequeñas especies

Feeding and Nutrition of Anteaters

The superorder Xenarthra (former Edentata) is grouped into two orders, Cingulata (armadillos) and Pilosa (anteaters and sloths). These are special mammals that show unique traits: (1) the existence of secondary articulations called xenarthrales located between the lumbar vertebrae and the spinal column; (2) the presence of fused pelvic bones; and (3) very low metabolic rate and variable body temperatures, which allow xenarthrans to conserve energy. They are also highly specialized, but diverse in terms of dietary needs. Xenarthrans include strict folivores such as the three-toed sloth (Bradypodidae), omnivore-generalists such as the two-toed sloth (Choloepus spp.), specialized carnivores such as the giant anteater (Mymecophaga tridactyla), and the tamanduas (Tamandua tetradactyla, T. mexicana). Armadillos vary in their diet, with certain species feeding mainly on ants and termites but others, such as the common Dasypus novemcinctus, are omnivorous.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigación en Nutrición Animal (CINA)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni