The commercial production of carnivorous fish depends on the feed training that can be made through the direct transition from natural food to inert food. As using live natural food requires care in production, alternative methods of using live food are necessary, such as freezing. Thus, the aim of this study was to evaluate the use of frozen zooplankton as an initial diet in the feed training of pirarucu Arapaima gigas juveniles. Three hundred and twenty pirarucu juveniles (13.94 ± 4.99 g) were submitted to weaning with two different initial diets (treatments): live zooplankton and frozen zooplankton. The co-feeding period was 12 days, with a progressive increase in the amount of feed offered and a decrease in zooplankton every three days. At the end of the training, all fish were ready to be fed with commercial feed. There was no mortality in the experiment and no significant differences (p > 0.05) for weight, length, weight variation coefficient, specific growth rate, intestinal coefficient, hepatosomatic index, muscle layer thickness and height of the branched folds intestinal mucosa, moisture, crude protein and carcass energy for fish that received live or frozen zooplankton as a starter. Isotopic values of δ¹⁵ N and δ¹³C in the fish's muscle were similar (p > 0.05), reinforcing no feeding preference of the fish between the live or frozen zooplankton. The water quality was not influenced by the use of initial diet (p > 0.05). The frozen zooplankton can be used as initial food for pirarucu juveniles feed training, without impairing fish growth and survival.

中文翻译：

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在巨骨舌鱼断奶期间，冷冻浮游动物作为天然食物是有效的

肉食性鱼类的商业化生产取决于可以通过从天然食物直接过渡到惰性食物进行的饲料培训。由于使用活的天然食物需要在生产过程中小心谨慎，因此需要使用其他方法使用活的食物，例如冷冻。因此，本研究的目的是评估冷冻浮游动物作为初始饮食在巨骨舌鱼的饲料训练中的使用少年。320 只皮拉鲁古幼鱼 (13.94 ± 4.99 g) 接受了两种不同的初始饮食（处理）：活浮游动物和冷冻浮游动物的断奶。共同喂养期为 12 天，提供的饲料量逐渐增加，每三天浮游动物减少。在训练结束时，所有的鱼都准备好用商业饲料喂养。实验中无死亡率，体重、身长、体重变异系数、比生长率、肠道系数、肝体指数、肌层厚度、肠黏膜分枝皱襞高度、水分、粗接受活的或冷冻的浮游动物作为起始鱼的蛋白质和胴体能量。δ ¹⁵  N 和 δ 的同位素值鱼肌肉中的¹³ C 相似（p > 0.05），加强了鱼在活的或冷冻的浮游动物之间没有摄食偏好。水质不受初始饮食的影响（p > 0.05）。冷冻的浮游动物可作为梨形虾幼鱼饲料训练的初始食物，不影响鱼的生长和存活。