scholarly journals A Deep Insight of Spermatogenesis and Hormone Levels of Aqua-Cultured Turbot (Scophthalmus maximus)

2021 ◽  
Vol 7 ◽  
Author(s):  
Yifan Liu ◽  
Qinghua Liu ◽  
Shihong Xu ◽  
Yanfeng Wang ◽  
Chengcheng Feng ◽  
...  

Turbot (Scophthalmus maximus) is an important marine fish both in Europe and North China. Although there are plenty of studies on the reproduction of turbot, the complete cytological process of spermatogenesis remains unclear. In this study, we investigated the submicroscopic structure of total 23 types of male germ cells throughout the breeding season, with a relatively complete process of the primary spermatocytes. We found that the spermatid tail formed early at Spermatid II, and there were at least 16 spherical mitochondria in the spermatozoa. The hepatosomatic index (HSI) and gonadosomatic index (GSI) both peaked during the breeding season. Preliminary analysis showed that the vitality of mature sperm was negatively correlated with the proportion of sperm deformity. The serum 3,5,3′-triiodothyronine (T3), 5-hydroxytryptamine (5-HT), testosterone (T), 17α,20β-Dihydroxy-4-pregnen-3-one (17α,20β-DHP), and 17β-estradiol (E2) all increased during the maturity period, with the change of T content most noticeable. Whereas in the testis, an overall high level of 11-ketotestosterone (11-KT) was more remarkable. The expression and localization of androgen receptor (AR) mRNA showed that the AR was highly expressed at the stages of II (15 – 70 g), with a slight rebound at the mature stages [IV(2200 g) to V(2500 g)], whose change was ahead to the changes of T and 11-KT. Fluorescence in situ hybridization (FISH) analysis showed that the AR mainly distributed in but not limited to Sertoli cells. This study represents the most complete overview of the reproductive cycle and spermatogenesis of turbot, which provides an important reference for the reproduction research and the guidance of flatfish breeding.

2021 ◽  
Vol 29 (3) ◽  
pp. 164-175
Author(s):  
Bohdan Hulak ◽  
Yevhen Leonchyk ◽  
Volodia Maximov ◽  
George Tiganov ◽  
Vladislav Shlyakhov ◽  
...  

Abstract Turbot is one of the most valuable fish species in the Black Sea commercial fishery. The serious, dramatic depletion of the turbot stock and catches that began in the 1980s was caused by overfishing and poor ecological conditions. The state of the turbot stock began to improve in the northwestern part of the Black Sea in 2016. Landings were at their 30-year maximum in this part of the sea. Catches per unit effort (CPUEs) have been at a stable, high level there for the last few years. Average turbot weight and length have also been increasing. The Stock Synthesis (SS3) framework was used in the stock assessment. According to SS3 analysis, fishing mortality (F) reached the minimum level of 0.29 in 2018. The cumulative SPR (Spawner Potential Rate) index was 0.27, which approximately equaled SPRMSY = 0.25. Thus, currently the turbot stock is mostly moderately exploited at a level close to the management target in the northwestern part of the Black Sea. However, the entire Black Sea population has not fully recovered yet.


2020 ◽  
Vol 70 (2) ◽  
pp. 131-143
Author(s):  
Farideh Mohseni ◽  
Tooraj Valinassab ◽  
Ehsan Ramezani-Fard ◽  
S.M. Reza Fatemi ◽  
Mohammad Seddiq Mortazavi

Abstract Catfish are an important component of demersal fisheries in the Persian Gulf. This study describes reproductive aspects in the four common species of catfish, namely Netuma thalassina (Rüppell, 1837), Netuma bilineata (Valenciennes, 1840), Plicofollis dussumieri (Valenciennes, 1840), and Plicofollis layardi (Günther, 1866) collected from coastal areas of the Persian Gulf during spring and winter 2017. A total of 495 fishes were collected, including 151 N. thalassina, 12 N. bilineata, 212 P. dussumieri, and 120 P. layardi. The four species showed significant differences in total length as a measure of body size. Total length of these four species also differed significantly between the four seasons and between the sexes. Three species, i.e., N. thalassina, P. dussumieri, and P. layardi showed an overall female-biased sex ratio, while the sex ratio of N. bilineata did not differ from the expected equal proportions. The patterns of gonad development, gonadosomatic index, and hepatosomatic index of the four species showed that the breeding season of N. thalassina, P. dussumieri, and P. layardi was probably during winter. N. bilineata showed a different pattern; its breeding season is therefore expected to be spring. The size at first maturity of N. thalassina, P. dussumieri, N. bilineata, and P. layardi, was 44.99, 30.55, 29.60, and 27.01 cm, respectively. This study provides essential information for correct management during the reproductive cycle to maintain a healthy stock of these fishes.


ISRN Zoology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Alaa G. M. Osman ◽  
El Sayed H. Akel ◽  
Mahmoud M. S. Farrag ◽  
Mohsen A. Moustafa

Maturity stages of round herring Etrumeus teres were divided anatomically into six stages. Monthly distribution of such maturity stages showed that E. teres had prolonged spawning season extended from December to May for females and to July for males. The observed sex ratio was 1 : 2 (male: female). Gonadosomatic index (GSI) values were high during breeding season for both sexes. Hepatosomatic index (HIS) values for females increased from December to April and from December to July for males. Both sexes of E. teres showed the same correlation between GSI and HSI during their breeding season. The absolute and relative fecundity increased with increasing of length and weight. Histologically, the ovarian cycle of E. teres was classified into six stages and the testicular cycle into five stages. Female of E. teres was a multiple spawner and had prolonged spawning season with a group-synchronous ovarian which contained oocytes at all stages of development. Also, different sizes of spermatocytes at different developmental stages of maturation were observed during the same season. This may reflect the suitability of the specific reproductive behavior of male and its adaptation to the prolonged spawning season with females.


2013 ◽  
Vol 37 (7) ◽  
pp. 1073
Author(s):  
Yujuan WANG ◽  
Xiuhua WANG ◽  
Wen HAN ◽  
Rui WANG ◽  
Jie HUANG

Fishes ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
Jie Cao ◽  
Qi Wang ◽  
Jun Mei ◽  
Jing Xie

This study evaluated the effect of different concentrations (20, 40 and 60 mg/L) of 3-aminobenzoic acid ethyl ester methanesulfonate (MS-222) on the quality changes in turbot during simulated transport in water. The results showed that the ammonia nitrogen content in the transportation water of each sample increased significantly, and the dissolved oxygen level decreased. The dissolved oxygen content in MS-222-treated samples was higher than that of control group (CK) samples. For turbot flesh quality, simulated transport in water led to a decrease in moisture, fat and protein contents in all samples. The MS-222-treated turbot samples showed higher pH values, glycogen contents, springiness and chewiness values and lower lactic acid contents comparing with the CK samples during simulated transport in water. In addition, the fresh and bitter amino acids in the muscle of turbot increased in each treatment group compared to the non-transported fish at the end of the simulated transport. The results showed that MS-222 treatment could retard the turbot transport stress and improve the quality of turbot during simulated transport in water.


Sign in / Sign up

Export Citation Format

Share Document