Feeding strategies on larval rearing of severum (Heros severus) (Heckel, 1840), Amazonian ornamental fish

ABSTRACT The aim of this study was to evaluate the supply time of artemia and the period of food transition to post-larvae of severum (Heros severus). A total of 450 post-larvae of severum were distributed in 45 aquaria, in a completely randomized design, in a 3x5 factorial scheme, with three replicates. Three feeding periods with artemia nauplii were evaluated: zero, five, and ten days. In addition, five feeding transitions were tested: one, two, three, four and five days, when the animals received joint feeding of artemia nauplii and dry diet. At the end of the experiment the fish were counted, weighed and photographed, to evaluate the productive performance and the morphometric variables. For all parameters evaluated, no interaction between the time of artemia supply and the feeding transition period was observed. Animals fed for 10 days with artemia nauplii showed the best performance results and the highest morphometric variables. The fish that received joint feeding for three days presented satisfactory development. Thus, 10 days of artemia nauplii supply and three days of feeding transition is recommended before starting the exclusive supply of diet inert to post-larvae of severum.

摘要
本研究旨在评估卤虫（Artemia）投喂时长，以及向Severum慈鲷（Heros severus）后期幼体的饵料转换周期。本实验共选取450尾该慈鲷后期幼体，将其分配至45个水族箱中，采用3×5因子设计的完全随机分组方案，设置3个生物学重复。
实验设置了3个卤虫无节幼体（Artemia nauplii）投喂时长梯度：0天、5天与10天；此外设置5种饵料转换周期处理：当试验幼体接受卤虫无节幼体与干配合饲料联合投喂时，转换周期分别为1天、2天、3天、4天及5天。
实验结束后，对所有试验鱼进行计数、称重及拍照，以评估其生产性能与形态测量指标。针对所有测定参数，未观察到卤虫投喂时长与饵料转换周期之间存在交互作用。其中，采用卤虫无节幼体投喂10天的试验组，生产性能最优，形态测量指标数值最高；采用3天联合投喂模式的试验组，试验鱼生长发育状况良好。
综上，在向Severum慈鲷（Heros severus）后期幼体投喂单一惰性饵料前，推荐先进行10天的卤虫无节幼体投喂，并设置3天的饵料转换周期。