Characteristics of induced triploid Far Eastern catfish, Silurus asotus

Abstract

The objective of this study is to determine characteristics of induced triploid Far Eastern catfish, Silurus asotus: comparative analysis of cell cycle, expression of cell cycle protein, histological characteristics, morphometric characteristics, physiological response, body composition, hematological characteristics, concentrations of sex hormone and growth hormone, occurrence of amitosis were analyzed in diploid and induced triploid Far Eastern catfish.

Cell cycle of gill tissue were significantly different in the percentages of each cell cycle fraction between diploid and induced triploid Far Eastern catfish (P<0.05). Cyclin D1 and cyclin E expressions after organized damage were lower than those before organized damage in both tissues of diploid and induced triploid Far eastern catfish, respectively. In all experimental groups, protein expressions of induced triploid were higher than those of diploid. Significant difference of cyclin D1 and cyclin E expressions were not determined between gill tissue and tail fin tissue.

Cell and nuclear size of induced triploid Far Eastern catfish were higher than those of diploid Far Eastern catfish, however cell number were lower than diploid.

Significant variables of morphometric characteristic between diploid and induced triploid Far Eastern catfish were the direct distance between the anterior edge of the lower lip and the anterior insertion of the dorsal fin (DALAD), the horizontal distance between the anterior edge of the lower lip and the anterior insertion of the ventral fin (HALAV), the direct distance between the anterior edge of the upper lip and the first nostril (DAUF), the direct distance between the anterior edge of the upper lip and the second nostril (DAUS), the interorbital width (IW), and the mandible barbel length (ManBL). Therefore, induced triploid had smaller heads and shorter mandible barbels than diploid.

Stress hormone concentrations and reaction velocity of diploid Far Eastern catfish were generally higher and slower than those of induced triploid Far Eastern catfish. In addition, stress hormone concentrations of low water temperature stress was higher than those of high water temperature stress.

The differences body compositions and hormonal parameters between the diploid and induced triploid Far Eastern catfish were investigated in the spawning and non-spawning season. Spawning season in May and non-spawning season in January were determined at 2014, respectively. Estradiol and testosterone of diploid were higher than those of induced triploid in spawning season (P<0.05). Thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). However, estradiol, testosterone, thyroid stimulating hormone and thyroxine were not different significantly between diploid and induced triploid in non-spawning season.

Erythrocyte count of diploid Far Eastern catfish was higher than that of induced triploid Far Eastern catfish in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were significantly higher than those of diploid in both seasons (P<0.05).

Crude fat of induced triploid Far Eastern catfish was higher than diploid Far Eastern catfish in spawning season, but there was no significant difference of crude fat between diploid and induced triploid in non-spawning season.

The types of atypical cell were determined three types in Far Eastern catfish

메기, Silurus asotus 유도 3배체의 특징을 구명하기 위해서 본 연구는 메기 3배체를 유도하여 이들의 세포주기, 조직학적 특징, 계측형질, 생리학적 특징, 체조성, 혈액학적 특징, 성호르몬 및 성장호르몬의 농도, 그리고 비정형 적혈구의 출현 여부를 2배체 메기와 비교․조사하였다.

메기 2배체와 유도 3배체를 대상으로 아가미조직의 세포주기 및 단백질 발현을 조사한 결과, cell cycle fraction간 비율에서 2배체와 유도 3배체간의 유의한 차이가 나타났으며(P<0.05), 유도 3배체의 세포주기 단백질, cyclin D1과 cyclin E의 발현량이 2배체 보다 높게 나타났다. 유도 3배체의 세포와 핵의 크기가 2배체 보다 크게 나타났으나 반면, 세포수는 2배체 보다 낮게 나타났다(P<0.05).

계측형질 중 유의한 차이를 보인 항목은 direct distance between the anterior edge of the lower lip and the anterior insertion of the dorsal fin (DALAD), the horizontal distance between the anterior edge of the lower lip and the anterior insertion of the ventral fin (HALAV), the direct distance between the anterior edge of the upper lip and the first nostril (DAUF), the direct distance between the anterior edge of the upper lip and the second nostril (DAUS), the interorbital width (IW) 및 the mandible barbel length (ManBL)로 나타났다(P<0.05). 즉, 유도 3배체 메기는 2배체에 비해 비교적 작은 머리 및 짧은 하악수염을 가진 것으로 나타났다.

스트레스 반응의 경우, 2배체 메기의 스트레스 호르몬의 농도 및 반응속도가 전반적으로 유도 3배체 메기에 비해 높고 천천히 증가하였으며, 저온 스트레스가 고온 스트레스에 비해 더 높게 나타났다(P<0.05).

2014년에 산란기(5월)와 비산란 시기(1월)의 2배체 메기와 유도 3배체 메기를 대상으로 체조성과 호르몬 변화를 측정한 결과, 산란기의 estradiol과 testosterone 함량은 2배체가 유도 3배체 보다 높게 나타났으나, thyroid stimulating 호르몬과 thyroxine 함량은 유도 3배체가 2배체에 비해 더 높게 나타났다(P<0.05). 그러나 비산란시기의 estradiol, testosterone, thyroid stimulating 호르몬과 thyroxine 함량은 2배체와 3배체간에서 유의한 차이가 나타나지 않았다(P>0.05).

2배체 메기의 적혈구 수는 측정 시기와 관계없이 유도 3배체 메기에 비해 높게 나타났고, 평균 혈구용적과 평균 혈구 혈색소 함량은 유도 3배체가 2배체에 비해 높게 나타났다(P<0.05).

산란시기에 유도 3배체 메기의 조지질 함량이 2배체 메기에 비해 월등히 높게 나타났으나(P<0.05), 비산란시기가 되면서 2배체간에서 유의한 차이가 나타나지 않았다(P>0.05).

비균형 분열, 불규칙적인 핵의 모양 및 핵의 부재와 같은 비정형 적혈구 유형이 2배체 메기와 유도 3배체 메기에서 관찰되었으며, 유도 3배체의 비정형 적혈구 출현 빈도가 2배체에 비해 높게 나타났다(P<0.05).

본 연구는 유도 3배체의 불임 현상을 조직학, 형태학 및 생리학적 특징 측면에서 구명하였다. 본 연구의 조직학적 특징을 통해 유도 3배체 메기의 거대화(giantism)가 나타나지 않는 이유를 파악하였으며 아울러, 호르몬 변화 측정을 통해 유도 3배체 메기의 불임으로 인한 성숙에너지의 전환을 설명하였다. 본 연구의 결과들은 양식산업에서 생산성 향상을 위한 어류 유도 3배체에 관한 정보제공과 아울러 기존 관련 연구들을 보완할 것으로 사료된다.

asymmetric division, irregular-shaped and absence of nucleus. Occurrence frequency of amitosis-like nuclear division in induced triploid was higher than that in diploid.

This study was determined sterility and other characteristics of induced triploid by histology, morphology and physiology. The reason why this condition doesn’t cause giantism is proved by histological characteristics. In addition, comparative analysis of sex hormone and growth hormone between diploid and induced triploid were proved to convert the energy used in the reproductive growth of the body. Therefore, the result of this study could use evidence of previous studies about induced triploid for improvement of productivity in a fish aquaculture industry.