The present study evaluated the effect of voluntary ingestion of duckweed (Lemna minor) on the growth and productive performance of Nile tilapia (Oreochromis niloticus) reared in a recirculation system (RAS). The constant availability of fresh lemna was compared with a control treatment without supplementation. In both treatments, the fish were fed a commercial feed for 28 days. The experimental design was completely randomized with two treatments and seven replications. Nile tilapia juveniles (21.95 ± 0.22 g) were acclimated in 14 tanks (70 l) with a density of 10 fish per tank. All fish were fed daily with an extruded commercial diet (32% CP), three times a day, until apparent satiety. An amount of lemna was manually collected daily, washed, drained, and treated with absorbent paper to remove excess surface water, and then weighed and supplied to the tilapia tanks. Daily consumptions of feed and lemna were quantified. At the beginning of the experiments and after 28 days, all fish were fasted for 24 h, then anesthetized with eugenol (50 mg l⁻¹), and weighed individually. Nile tilapia juveniles grown in a RAS can voluntarily ingest up to 0.5% of live weight in fresh lemna with no effects on growth and productive performance. The amount of lemna consumed decreased over time, from 0.5 to 0.2% of body weight. The fish that were exposed to lemna consumed less feed in the first week of the experiment, but this reduction was compensated over time with no impact on the total feed consumption (478.59 ± 21.74 g).

本研究评估了自愿摄入浮萍（Lemna minor）对尼罗罗非鱼（Oreochromis niloticus）生长和生产性能的影响。) 在再循环系统 (RAS) 中饲养。将新鲜 lemna 的恒定可用性与没有补充的对照处理进行比较。在这两种处理中，鱼都喂了 28 天的商业饲料。实验设计完全随机，有两个处理和七个重复。尼罗罗非鱼幼鱼 (21.95 ± 0.22 g) 在 14 个鱼缸 (70 l) 中驯化，每个鱼缸的密度为 10 条鱼。所有的鱼每天都用膨化的商业饲料 (32% CP) 喂养，每天 3 次，直到出现明显的饱腹感。每天手动收集一定量的 lemna，清洗、沥干并用吸水纸处理以去除多余的地表水，然后称重并提供给罗非鱼鱼缸。对饲料和 lemna 的每日消耗进行量化。实验开始时和 28 天后，所有鱼禁食 24 h，⁻¹ )，并单独称重。在 RAS 中生长的尼罗罗非鱼幼鱼可以自愿摄取高达 0.5% 的新鲜 lemna 活重，而不会影响生长和生产性能。消耗的 lemna 量随着时间的推移而减少，从体重的 0.5% 到 0.2%。暴露于 lemna 的鱼在实验的第一周消耗较少的饲料，但这种减少随着时间的推移得到补偿，对总饲料消耗 (478.59 ± 21.74 g) 没有影响。