J Fish Biol. 2014 Mar;84(3):844-63. doi: 10.1111/jfb.12289.
Observations of the Magadi tilapia Alcolapia grahami in hot, highly alkaline Lake Magadi revealed that they air breathe not only during hypoxia, as described previously, but also during normoxia and hyperoxia. Air breathing under these latter conditions occurred within distinct groupings of fish (pods) and involved only a small proportion of the population. Air breathing properties (duration and frequency) were quantified from video footage. Air breathing within the population followed a diel pattern with the maximum extent of pod formation occurring in early afternoon. High levels of reactive oxygen species (ROS) in the water may be an irritant that encourages the air-breathing behaviour. The diel pattern of air breathing in the field and in experiments followed the diel pattern of ROS concentrations in the water which are amongst the highest reported in the literature (maximum daytime values of 2.53 – 8.10 μM H₂O₂). Interlamellar cell masses (ILCM) occurred between the gill lamellae of fish from the lagoon with highest ROS and highest oxygen levels, while fish from a normoxic lagoon with one third the ROS had little or no ILCM. This is the first record of air breathing in a facultative air-breathing fish in hyperoxic conditions and the first record of an ILCM in a cichlid species.
在高温、高碱性的马加迪湖对马加迪罗非鱼 Alcolapia grahami 的观察表明，它们不仅在先前描述的缺氧时进行空气呼吸，在正常氧和高氧时也会进行空气呼吸。在这些后一种情况下，空气呼吸发生在鱼类的特定群体（鱼群）中，只涉及人口的一小部分。空气呼吸特性（持续时间和频率）从视频片段中量化。种群内的空气呼吸遵循昼夜节律，鱼群形成的最大程度发生在午后早些时候。水中高水平的活性氧物质 (ROS) 可能是一种刺激物，促使鱼类进行空气呼吸行为。现场和实验中的空气呼吸昼夜节律与水中 ROS 浓度的昼夜节律一致，水中 ROS 浓度是文献中报道的最高水平之一（白天最高值为 2.53-8.10 μM H₂O₂）。在 ROS 最高和氧气水平最高的泻湖中的鱼类的鳃片之间出现了板间细胞团（ILCM），而在 ROS 减少三分之一的正常氧泻湖中，鱼类的 ILCM 很少或没有。这是首次在高氧条件下记录到兼性空气呼吸鱼类的空气呼吸，也是首次在慈鲷物种中记录到 ILCM。
