Efficacy of 17 α‐methyl testosterone and letrozole on sex reversal of protogynous grouper,Epinephelus tauvina (Forskal, 1775) and spawning performance of sex‐reversed males

This study aimed to test the efficacy of 17 α‐methyl testosterone (17 α‐MT) alone and in combination with letrozole, an aromatase inhibitor, for the induction of sex reversal in protogynous greasy grouper, Epinephelus tauvina. Further, the long‐lasting effects of these treatments and spawning performance of sex‐reversed males were also investigated. Greasy grouper with oocytes in the perinucleolus stage were implanted with 5 mg 17 α‐MT kg^?1 body weight (T₁), 5 mg 17 α‐MT and 0.2 mg letrozole kg^?1 body weight (T₂) and 5 mg 17 α‐MT with 0.4 mg letrozole kg^?1 body weight (T₃) and no androgens/enzyme inhibitor implanted (C). The 17 α‐MT alone and in combination of letrozole‐induced sex reversal in greasy grouper, whereas untreated control fish (C) showed normal ovarian development. However, T₂ and T₃ group showed 100% sex reversal and completion of spermatogenesis up to functional male phase in 2 and 3 months, respectively, whereas T₁ group resulted in only 66.67% functional male with motile spermatozoa after 4 months. Sex‐reversed males successfully fertilized the eggs during induced spawning. There were significant differences on fertilization and hatching rates between T₂ group (79.00 ± 4.36%; 77.67 ± 2.87%, respectively) and T₁ group (57.67 ± 3.17%; 63.87 ± 2.91%, respectively). The result suggested that 17 α‐MT (5.0 mg kg^?1 BW) in combination with letrozole (0.2 mg kg^?1 BW) has the potential to produce 100% sex‐reversed male in short period in greasy grouper, which might greatly help in seed production of greasy grouper.     

中草药饲料添加剂对黄鳝性激素含量的影响

试验以初始平均体重为（41.2±2.3）g 的雌黄鳝和初始体重为（113.5±5.6）g 雄黄鳝为研究对象,分别配置含中草药质量浓度为3%、4%、5%的鱼糜饲料,每组设置3 个重复,连续投喂31 d（其中前10 d 为无中草药的训食阶段,后21 d 为添加中草药试验阶段）并进行抽血采样,测定其血清内雌二醇与睾酮的含量,来评价饲料中的中草药浓度对黄鳝性激素含量的影响,实验结果表明：（1）与对照组相比,摄食不含中草药饲料的亲鱼血液中雌二醇与睾酮的含量显著高于含中草药饲料的亲鱼(P <0.05),并且亲鱼血清内雌二醇与睾酮的含量随着中草药浓度的增加而降低(P <0.05);（2）从时间的角度分析得出的结论是,雌鱼血清内的雌二醇含量与雄鱼血清内的睾酮含量,在各个试验组中,都随着时间的积累而呈现降低的趋势(P<0.05)。     

Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)

Objective   Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel.
Procedure   A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population.
Results   Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min.
Conclusion   Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status.     

雌激素和雄激素对鸡成骨细胞增殖、凋亡、细胞周期及其受体mRNA转录的影响

为探讨雌激素和雄激素对鸡胚额骨成骨细胞(OB)增殖、凋亡、细胞周期及其受体mRNA转录的影响,用雌激素(17β雌二醇)和雄激素(十一酸睾酮)单独以及联合处理鸡胚额骨成骨细胞,MTT法测定细胞增殖率,流式细胞仪检测细胞凋亡和细胞周期的变化,荧光定量PCR检测成骨细胞中雌激素受体(ER)及雄激素受体(AR)mRNA的转录。结果显示:一定浓度的雌激素或雄激素在24h内均能促进成骨细胞的增殖,促进成骨细胞的细胞周期进程,但对细胞凋亡无明显作用。雌激素单独或联合雄激素作用能上调ERmRNA的转录,对ARmRNA的转录无明显作用。     

口服鲨烯对大鼠Leptin、体脂沉积和繁殖的影响

将22日龄Wistar雄鼠32只,分对照组(饲料中不含鲨烯)和试验组(每千克饲料中含鲨烯1 000mg),宰杀后测定血Leptin、血糖、胆固醇、甘油三酯和睾酮水平及体重脂肪指数和体重睾丸指数,同时,各组留6只与雌鼠交配,待观察产仔数.结果显示,对照组和试验组饲料消耗没有差异,但试验组大鼠体重、体重脂肪指数、血Leptin、血糖、胆固醇和甘油三酯水平显著比对照组低,而试验组大鼠的体重睾丸指数、血睾酮水平和产仔数显著比对照组高.提示口服鲨烯可防止正常鼠体重和体脂肪增加并可降低肥胖鼠体重脂肪指数及降低血Leptin、血糖、胆固醇和甘油三酯的水平;同时,鲨烯可促进睾丸生长发育和睾酮分泌,增加产仔数.     

Kisspeptin injection improved the semen characteristics and sperm rheotaxis in Ossimi ram

The aim of the present study was to investigate the effect of kisspeptin-10 (Kp10) injection on semen characteristics, testosterone (T) production and sperm rheotaxis using microfluidic devices in immature ram. Computer-assisted sperm analysis (CASA) with controlled flow velocity was used to explore the kinetic parameters of sperm and positive rheotaxis (PR %). PR % was defined as the number of PR sperms over the number of motile sperms. Healthy Ossimi rams were randomly divided into two groups; a saline-treated control group and Kp10-treated one (5 µg/kg body weight). Treatments were given by intramuscular injection once a week for 1 month. After 1 month, the semen was collected and evaluated weekly for 6 weeks, while the blood samples were collected every 2 weeks for the next 8 weeks. Semen properties were significantly affected by Kp10 injection (p < .01). The Kp10 increased the volume, sperm concentration and percentages of live sperm compared with those of control. Additionally, sperm trajectories and rheotaxis get improved by the injection of Kp10 with time. Furthermore, kisspeptin improved the secretion of testosterone levels throughout the period of study. In conclusion, injections of the Kp10 had a positive impact on semen characteristics as well as improved sperm rheotaxis of Ossimi rams in subtropics.     

L-精氨酸对热处理MLTC-1细胞氧化、凋亡及睾酮合成相关基因表达的影响

试验旨在研究热处理对睾丸间质细胞的影响及L-精氨酸对热处理睾丸间质细胞抗氧化、抗凋亡及睾酮合成相关基因表达的影响。试验选用小鼠睾丸间质瘤细胞系(MLTC-1)细胞,将细胞分为4组,分别为对照组(C)、热处理组(HT)、5μg/mL L-精氨酸+热处理组(5H)和10μg/mL L-精氨酸+热处理组(10H),处理结束后收集培养上清液或细胞备用。结果显示:与C组相比,热处理显著降低MLTC-1细胞GSH-Px活力(P<0.01),当添加10μg/mL L-精氨酸后,GSH-Px活力得到恢复,并显著增加(P<0.01);热处理诱发细胞凋亡,添加L-精氨酸后,细胞凋亡数量明显降低;与HT组相比,添加5μg/mL L-精氨酸显著增加抗凋亡基因PI3K和Bcl-2的基因表达量(P<0.05);与HT组相比,5H组睾酮合成相关基因,StAR和Cyp17a1基因表达量极显著增加(P<0.01),SF-1的基因表达量也显著增加(P<0.05)。以上结果说明:L-精氨酸可缓解热处理诱导的MLTC-1细胞凋亡,增强MLTC-1细胞的抗氧化和抗凋亡能力,并可调控热处理MLTC-1细胞睾酮合成相关基因的表达。     

Effects of low dietary protein level on serum oestradiol,testosterone and sex reversal in rice field eel,Monopterus albus (Zuiew)

We investigated the effects of low dietary protein in isocaloric diets on sex reversal of Monopterus albus by evaluating the oestradiol (E₂) and testosterone (T) concentrations, gonadosomatic index (GSI), sex ratio and gonad structure at the histological level. Fish (9.50 ± 1.50 g average initial weight; n=3 per group) were fed with five practical diets containing 100, 150, 200, 250 or 400 g kg^?1 crude protein to apparent satiation for 15 months. Serum E₂ and T concentrations were determined by radioimmunoassays. E₂ concentrations and GSI significantly increased while T concentrations decreased as the dietary protein level was raised. Fish fed 400 g kg^?1 of dietary protein had significantly higher E₂ concentrations and GSI than those fed with lower dietary protein levels. The T concentrations of fish fed 100 g kg^?1 of dietary protein was significantly higher than that of fish fed higher dietary protein levels. The shift of sex ratio towards more male and intersex fish was observed with decreasing dietary protein levels. Therefore, low dietary protein level may promote sex change from female to male in M. albus. This study provides important information for successful reproductive management and may be exploited for aquaculture of this species.