Jimenez Yordano E, Parsons Jake W, Brainerd Elizabeth L
Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA.
Department of Biology, Tufts University, Medford, MA 02155, USA.
J Exp Biol. 2023 Feb 15;226(4). doi: 10.1242/jeb.244714. Epub 2023 Feb 24.
Most fish species use concentric epaxial and hypaxial contractions to suction feed, whereby both muscle groups produce cranial expansion and negative intraoral pressures. In contrast, channel catfish (Ictalurus punctatus) suction feed with little to no cranial elevation and epaxial shortening, generating suction power primarily with hypaxial shortening and pectoral girdle retraction. We hypothesized that channel catfish (1) actively anchor the head via isometric contraction of the epaxials and (2) vary feeding performance by modulating the absolute and relative outputs of the co-contracting muscles. We used a combination of electromyography, intraoral pressure recordings and specimen manipulation, and developed a new dual-lever model to explore this idea. We detected epaxial and hypaxial co-contraction prior to suction force development in all strikes. Our model revealed that the differential between the co-contracting muscles may be used to modulate suction pressure and strike accuracy.
大多数鱼类利用轴上肌和轴下肌的同心收缩进行吸力摄食，即这两组肌肉都会产生颅骨扩张和口腔内负压。相比之下，斑点叉尾鮰（Ictalurus punctatus）在吸力摄食时几乎没有或没有颅骨抬高和轴上肌缩短，主要通过轴下肌缩短和肩带后缩产生吸力。我们假设斑点叉尾鮰（1）通过轴上肌的等长收缩主动固定头部，（2）通过调节协同收缩肌肉的绝对和相对输出量来改变摄食性能。我们结合使用肌电图、口腔内压力记录和标本操作，并开发了一种新的双杠杆模型来探究这一想法。我们在所有攻击的吸力产生之前检测到轴上肌和轴下肌的协同收缩。我们的模型表明，协同收缩肌肉之间的差异可用于调节吸力压力和攻击准确性。
