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RESUMEN Se evaluó el efecto de la restricción de alimento y posterior realimentación sobre algunas variables fisiológicas en yamú (Brycon amazonicus) utilizando 1115 juveniles (peso inicial 217,75 g ± 14,74 g) distribuidos en tres estanques y asignados a los siguientes tratamientos: 1) Control (C), alimentación todos los días; 2) Restricción moderada (RM), restricción por 2 días y realimentación por 3 y 3) Restricción severa (RS), restricción total durante 5 semanas y realimentación a partir de la semana 6 hasta la 12. Se realizaron colectas de sangre los días 1, 35, 42, 56, 70 y 84, de 7 animales por tratamiento para determinación del hematocrito, proteína, glucosa, lactato, triglicéridos, colesterol, cortisol, T3 e insulina. Adicionalmente, los animales se sacrificaron para retirar el hígado y determinar el glucógeno hepático. El modelo experimental fue mixto de efectos fijos, con 3 tratamientos y 6 muestreos, con anidamiento del muestreo en los tratamientos. Los datos se analizaron a través de análisis de varianza y en los casos en que hubo diferencias significativas se empleó la prueba de Tukey-Kramer. No hubo diferencias significativas (p > 0,05) para hematocrito, proteína, glucosa, cortisol y lactato entre los tratamientos en ninguna de las muestras tomadas. La insulina y T3 mostraron diferencias entre tratamientos en el día 35, pero no en el 84, igual a lo ocurrido con colesterol y glucógeno hepático. Los triglicéridos mostraron diferencias a lo largo del estudio, en el día 84 RS presentó menores niveles. Los resultados permiten concluir que pese a la restricción parcial de alimento, no se generaron efectos negativos sobre el metabolismo de Brycon amazonicus.
ABSTRACT The effect of food restriction and refeeding on some physiological variables in yamú (Brycon amazonicus) was evaluated using 1115 juveniles (initial weight 217.75 g ± 14.74 g), distributed in three ponds. The groups were randomly assigned one of the following treatments: 1) Control (C), fed every day; 2) Moderate restriction (MR), restriction during 2 days and refeeding during 3; and 3) Severe restriction (SR), total restriction during 5 weeks and refeeding from week 6 to 12. Blood samples from 7 animals from each treatment were taken on days 1, 35, 42, 56, 70, and 84 to determine hematocrit, proteins, glucose, lactate, triglycerides, cholesterol, cortisol, T3, and insulin. The animals were sacrificed and their livers removed to calculate the hepatic glycogen. The experimental design used was a fixed effects mixed model of 3 treatments and 6 samples, with sampling nesting in the treatments. A variance analysis was performed to analyze the data; the Tukey-Kramer test a variance analysis was used in the cases with significant differences. No significant differences (p> 0.05) were found for hematocrit, protein, glucose, cortisol, and lactate. The insulin and T3 showed differences among treatments on day 35, but not on day 84, the same as cholesterol and hepatic glycogen. Triglycerides showed differences throughout the study, SR showed the lowest levels on day 84. The results allow us to conclude that, despite the partial feed restriction, there were no adverse effects on the metabolism of Brycon amazonicus.
RESUMEN
El objetivo general del trabajo fue evaluar el efecto de la restricción de alimento sobre el desempeño productivo y fisiológico de juveniles de cachama blanca y sobre su conte nido muscular de proteína y energía. En cuanto al diseño experimental, este fue com pletamente al azar, con cuatro tratamientos y cuatro repeticiones, cada una con cuatro individuos. Se seleccionaron 64 individuos con 58,40 ± 6,56 g de peso (P) y 14,65± 0,75 cm de longitud total (LT), distribuidos aleatoriamente en 16 acuarios y sometidos durante ocho semanas a los siguientes tratamientos: de control (T0): alimentación dia ria; tratamiento 1 (T1): un día de ayuno y uno de alimentación; tratamiento 2 (T2): tres días de ayuno y dos días de alimentación, y tratamiento 3 (T3): dos días de ayuno y tres de alimentación. Se utilizó alimento de 35% de proteína, suministrado al 3% de la biomasa total dos veces al día. Al culminar el periodo experimental, los animales experimentales se anestesiaron y se les tomaron muestras de sangre para evaluar dife rentes parámetros metabólicos y hormonales. Posteriormente, se sacrificaron, pesaron y midieron; luego, se pesaron sus vísceras y una porción de músculo blanco se obtuvo para determinar el contenido de proteína y energía. Al final del ensayo, se calculó la sobrevivencia. Luego, de acuerdo con los resultados, se concluyó que no hubo diferencias significativas en la mayoría de los parámetros analizados, por lo que se infiere que los juveniles de cachama blanca son capaces de adaptarse metabólicamente a la carencia parcial de alimento y optimizar la respuesta en su desempeño.
The general purpose of this experiment was to evaluate the effect of food restriction on the productive and physiological performance of Cachama Blanca juveniles and on the content of protein and energy in their muscles. 64 animals, with an average weight (P) of 58.40 ± 6.56 g and 14.65 ± 0.75 cm of Total Length (LT), were divided at random in 16 tanks. During eight weeks the animals received the following treatments: daily feeding; treatment 1 (T1): one day of fasting followed by one day of feeding; treatment 2 (T2): three days of fasting and two days of feeding; and treatment 3 (T3): two days of fasting and three days of feeding. Food containing 35% protein, at 3% of the total biomass was supplied twice a day. At the end of the experimental period the animals were anaesthetized and blood samples were taken in order to evaluate different metabolic and hormonal parameters. Later, the animals were sacrificed, weighted and measured. The viscera, liver and a portion of white tissue were used in order to determine protein and energy. The experimental design was done completely at random with three treatments and four repetitions, each done with four animals. At the end of the experiment, survival rate was calculated. The results did not show significant differences in most of the parameters analyzed. It was concluded that the juveniles of Cachama Blanca are capable of adapting metabolically to the partial lack of food and of optimizing their performance response.
RESUMEN
Con el propósito de evaluar el efecto de la restricción alimenticia y la realimentación sobre la composición del músculo blanco de cachama blanca, se aplicaron dos protocolos de restricción alimenticia durante 84 días, cada uno dividido en un periodo de restricción alimenticia y un periodo de realimentación. En el primer protocolo, se aplicó una restricción alimenticia moderada (33,3%), y en el segundo, una restricción severa (50%); ambos grupos fueron comparados con un grupo control que recibió una ración alimenticia igual a la suministrada bajo condiciones de un cultivo comercial. Al finalizar el ensayo, ninguno de los tiempos de restricción alimenticia tuvo efectos significativos (p > 0,05) sobre el porcentaje de proteína del filete. Sin embargo, se observaron efectos significativos (p < 0,05) sobre los porcentajes de lípidos, cenizas y energía. Con respecto al porcentaje de cenizas musculares, se observó que la restricción alimenticia tendió a aumentar su valor, mientras que para el porcentaje de lípidos y los niveles de energía, se encontró el efecto contrario. No obstante, cuando los individuos finalizaron el periodo de realimentación, se observó un restablecimiento en los niveles de nutrientes comparados con los individuos no restringidos. En cuanto al perfil de ácidos grasos, el grupo control mostró con diferencias significativas (p < 0,05) mayor porcentaje de omega-3 (n-3). Estos resultados permiten concluir que los protocolos de alimentación aplicados estimularon, en Piaractus brachypomus, movilización de nutrientes musculares y su posterior restablecimiento, sin afectar la integridad del músculo blanco.
In order to evaluate the effect of food deprivation and re-feeding on the composition of cachama blanca white muscle, two restriction food protocols were used per 84 days, each one divided in a food restriction period and re-feeding period. In the first of them, it was used a moderate food restriction (33.3%) and in the second one, was a severe restriction (50%); both groups were compared with a control group receiving the samefood ration under commercial culture conditions. At the end of the trial, any of the times of food restriction had significant effects (p>0.05) on fillet protein percentage. However, significant differences (p<0.05) were observed on lipids, ash and energy percentages. In regards to muscle ash percentage, it was observed that food restriction tends to increase its value, and in contrast, was observed an opposite effect on lipids percentage and energy levels. However, when individuals completed the re-feeding period, a restoration in the levels of nutrients compared to non-restricted individuals was observed. As for the fatty acid profile, the control group showed with significant differences (p < 0,05) the highest percentage of omega-3 (n-3). These results suggest that restriction protocols applied in Piaractus brachypomus stimulated mobilization of nutrients muscle and its later restore without affecting the integrity of the white muscle.
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This paper reports the triiodothyronine's (T3) effects on the early growth and survival of piracanjuba (Brycon orbignyanus) produced from fertilized eggs hormone exposed. The study was carried out in two phases. In the first phase, eggs divided in 6 batches were immersed in T3 solutions: 0.01; 0.05; 0.1; 0.5 ppm; 1 ppm and control (no T3). After a 15-min immersion, eggs were transferred to incubators where larvae were kept up to 72 h after hatching. Larval weight, length and yolk sac volume were determined every 12 h. Sixty and 72 h after hatching, larvae exposed to 0.5 ppm T3 were significantly heavier than the others, and those exposed to 1 ppm T3 showed the lowest weight. The yolk sac absorption was not affected. In the second experimental phase, the resulting fry from the first phase were stocked into 3 boxes per treatment (5 larvae L(-1)) and fed with plankton, fish larvae and feed prepared in the hatchery (48% CP) in the first 3 days, plankton and feed from the 4th to the 10th day and only feed in the next (last) 5 days. Fry weight, length and specific growth rate were determined at 1, 5, 10 and 15 days. Survival was calculated in the last day. In the 15th day, fry length did not differ among treatments but the weight of the control group was higher. Higher survival in the T3-treated groups suggested lower predation among fry. The results allowed us to conclude that there was no expressive effect of T3 on the growth, but it improved the survival of the piracanjuba progeny.
Asunto(s)
Acuicultura/métodos , Peces/crecimiento & desarrollo , Triyodotironina/farmacología , Análisis de Varianza , Animales , Pesos y Medidas Corporales/veterinaria , Brasil , Femenino , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Masculino , Análisis de SupervivenciaRESUMEN
El creciente desarrollo de la acuicultura ha generado la intensificación de los sistemas de producción, aumentando así los problemas de estrés ocasionados por las prácticas rutinarias de manejo; por este motivo es necesario investigar sobre estrategias que contribuyan a disminuir el impacto de los diferentes factores estresantes a los que son sometidos los peces durante su proceso de producción en cautiverio. Este documento contiene una revisión acerca de la vitamina C (ácido ascórbico) y su posible efecto benéfico sobre el crecimiento, inmunidad, resistencia al estrés y supervivencia de los peces, a fin de dar a conocer posibles estrategias de suplementación que contribuyan a mejorar las respuestas productivas de las diferentes especies susceptibles de ser cultivadas.
The increasing development of aquaculture has generated the intensification of the production systems, increasing therefore the problems of stress caused by the routine practices of handling, for this reason it is necessary to implement strategies that contribute to diminish the impact of the different stress or factors to which the fish during their process of production in captivity are put under. This document contains a revision about vitamin C, and its possible beneficial effect on the growth, the immunity, the resistance to the stress or factors and survival of fish. The aim of review is present strategies suplementatción that they contribute to improve the productive answers of the different species from susceptible fish of operation in captivity.
