Effects of Glucose Chain Length of Various Carbohydrates and Frequency of Feeding on Their Utilization by Fingerling Carp

Abstract

Improvement in glucose and maltose utilization by carp with increased feeding frequency by at least 4 times daily was confirmed in a 6-week feeding study in which fingerling carp were fed 4 purified diets containing α-starch, dextrin, maltose or glucose, 2, 4 or 6 times daily. At twice daily feeding, the starch diet resulted in the best weight gain and feed efficiency. When the feeding frequency was increased from 2 to 4 or 6 times, the weight gains improved together with increased feed consumptions in all dietary treatments. All dietary groups achieved more than 500% weight gains in 6 weeks when fed 6 times, yet the differences among them became less than 6%. Whereas, significant deteriorations of feed efficiency were noted in all dietary groups and the longer the glucose chain length, the poorer the feed efficiency. Analyses of the body compositions carried out on the samples collected at the end of the feeding experiment revealed that glycogen contents in the hepatopancreas of the dextrin group were always lowest at all frequencies without any noticeable differences in the remaining groups. On the other hand, the starch group alone showed remarkable defferences in the whole carcass composition among all treatments; that is, their crude fat levels were highest with the lowest moisture contents at all three frequencies, but their ash contents were lowest at both 4 and 6-time feedings. None of these treatments showed any significant effect on the carcass protein level.