Study on morphological characteristics and hypoxia tolerance of <em>Culter alburnus</em> (♀) × <em>Magalobrama terminalis</em> (♂) and <em>Culter alburnus</em>

Abstract

<em>C. alburnus</em> (♀) × <em>M. terminalis</em> (♂) (<em>CM</em>) is a new national cultivar formed by interspecific hybridization between <em>C. alburnus</em> and <em>M. terminalis.</em> To explore the morphological characteristics and hypoxia tolerance of <em>CM</em> and <em>C. alburnus</em>, quantitative and countable traits were measured for <em>CM</em> and <em>C. alburnus</em>; then we conducted hypoxia stress research. The results: 1. The main characteristics of <em>CM</em> that differed from <em>C. alburnus</em> in appearance were an increase in body height and thickness, a small blunt pointed head, bulging back of the head, and large scales on the sides of the body. Among the countable traits, the numbers of lateral scales, upper lateral scales, and first-gill rakes of <em>CM</em> were significantly lower than those of <em>C. alburnus</em>, whereas the number of lower lateral scales was significantly greater than that of <em>C. alburnus</em>. 2. At the water temperature of 25 ℃, the DO value of <em>C. alburnus</em> was higher than that of <em>CM</em>. The Superoxide dismutase (SOD) or glutathione (GSH) index of <em>CM</em> increased more when it increased and decreased less when it decreased. The SOD or GSH index of <em>CM</em> was higher than that of the <em>CM</em> under the same hypoxic stress time. Therefore, it was speculated that <em>CM</em> might have stronger hypoxia tolerance than <em>C. alburnus</em>. In summary, <em>CM</em> was generally similar to <em>C. alburnus</em> in terms of morphological characteristics; however, there were differences in body height, body thickness, tail handle, and scales. It has been speculated that <em>CM</em> have a stronger tolerance to hypoxia.