Dhillon Rashpal S, Yao Lili, Matey Victoria, Chen Bo-Jian, Zhang An-Jie, Cao Zhen-Dong, Fu Shi-Jian, Brauner Colin J, Wang Yuxiang S, Richards Jeffrey G
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada; 2Department of Biology, San Diego State University, San Diego, California; 3Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing, China; 4Department of Biology, Queen's University, 116 Barrie Street, Kingston, Ontario K7L 3N6, Canada.
Physiol Biochem Zool. 2013 Nov-Dec;86(6):727-39. doi: 10.1086/673180. Epub 2013 Sep 23.
The gills of many fish, but in particular those of crucian carp (Carassius carassius) and goldfish (Carassius auratus), are capable of extensive remodeling in response to changes in oxygen (O2), temperature, and exercise. In this study, we investigated the interspecific variation in hypoxia-induced gill modeling and hypoxia tolerance in 10 closely related groups of cyprinids (nine species, with two strains of Cyprinus carpio). There was significant variation in hypoxia tolerance, measured as the O2 tension (P(O2)) at which fish lost equilibrium (LOEcrit), among the 10 groups of carp. In normoxia, there was a significant, phylogenetically independent relationship between mass-specific gill surface area and LOEcrit, with the more hypoxia-tolerant carp having smaller gills than their less hypoxia-tolerant relatives. All groups of carp, except the Chinese bream (Megalobrama pellegrini), increased mass-specific gill surface area in response to 48 h of exposure to hypoxia (0.7 kPa) through reductions in the interlamellar cell mass (ILCM) volume. The magnitude of the hypoxia-induced reduction in the ILCM was negatively correlated with LOEcrit (and thus positively correlated with hypoxia tolerance), independent of phylogeny. The hypoxia-induced changes in gill morphology resulted in reduced variation in mass-specific gill surface area among species and eliminated the relationship between LOEcrit and mass-specific gill surface area. While behavioral responses to hypoxia differed among the carp groups, there were no significant relationships between hypoxia tolerance and the Po2 at which aquatic surface respiration (ASR) was initiated or the total number of ASR events observed during progressive hypoxia. Our results are the first to show that the extent of gill remodeling in cyprinids is associated with hypoxia tolerance in a phylogenetically independent fashion.
许多鱼类的鳃，尤其是鲫鱼（Carassius carassius）和金鱼（Carassius auratus）的鳃，能够根据氧气（O2）、温度和运动的变化进行广泛的重塑。在本研究中，我们调查了10个密切相关的鲤科鱼类群体（9个物种，包括两株鲤鱼（Cyprinus carpio））在低氧诱导的鳃重塑和低氧耐受性方面的种间差异。在这10组鲤鱼中，以鱼类失去平衡时的氧张力（P(O2)）衡量的低氧耐受性存在显著差异。在常氧条件下，单位质量鳃表面积与失去平衡临界氧张力（LOEcrit）之间存在显著的、系统发育独立的关系，低氧耐受性较强的鲤鱼鳃比低氧耐受性较弱的亲缘种更小。除了团头鲂（Megalobrama pellegrini）外，所有鲤鱼群体在暴露于低氧（0.7 kPa）48小时后，通过减少板间细胞团（ILCM）体积，增加了单位质量鳃表面积。低氧诱导的ILCM减少幅度与LOEcrit呈负相关（因此与低氧耐受性呈正相关），与系统发育无关。低氧诱导的鳃形态变化导致物种间单位质量鳃表面积的差异减小，并消除了LOEcrit与单位质量鳃表面积之间的关系。虽然鲤鱼群体对低氧的行为反应不同，但低氧耐受性与开始水生表面呼吸（ASR）时的氧分压或在渐进性低氧过程中观察到的ASR事件总数之间没有显著关系。我们的结果首次表明鲤科鱼类鳃重塑的程度与低氧耐受性以系统发育独立的方式相关。
