Ritmos diarios de pH gástrico y actividad enzimática digestiva en doradas (Srus aurata L., 1758) alimentadas de día, de noche y aleatoriamente

Abstract

[EN] The influence of scheduled vs random feeding on dayly rhythm of gastric pH and digestive enzimes was investigated in Gilthead seabream. Fish of an initial body weight of 80g were feed at 15 h, 3 h and randomly during 2 weeks by a diet constituted on 5% of protein, 30% of carbohidrates and 20% of lipids, using gelatin and casein (1:5) as protein source, dextrin for carbohidrate and soybean oil and cod liver oil (1:3) for lipids. After this period fish were anesthetized and stomach and intestine were sampled and gastic pH in stomach measured every 4 hours (n=6). Stomach and intestine samples were inmediately frozen at -80ºC and stored until digestive enzimes analysis (amilase and proteases). Daily rhithm of gastric pH showed for the three treatements a downfall in the next hours to mealtime and fish feed randomly showed a similar curve (sampling day were feed at 15 h) to feeds at 15 h buth with lower pH values. In conclusion, this is the first study that shows the effect of random feeding on dayly rhythm of gastric pH, and suggest this parameter as a new welfare indicator.

[ES] Si un organismo es capaz de anticipar una comida, la ingesta de alimento y la utilización de nutrientes puede ser mejorada, permitiendo al animla preparar y optimizar los procesos digestivos y metabólicos, proporcionando una ventaja adaptativa (Strubbe y Van Dijk, 2002). Varios trabajos describen variaciones diarias del pH gastrointestinal en peces teleósteos (Yúfera et al., 2004, Yúfera y Darias, 2007) señalando una caída del pH durante la digestión gástrica, aunque el efecto del horario de alimentación y de la alimentación aleatoria sobre el ritmo de pH gástrico aún no se ha estudiado. Por ello, el objetivo de este trabjo fue investigar las variaciones diarias de pH gástrico y enzimas digestivas en doradas alimentadas de día, de noche y aleatoriamente.