Sex disparities determined by biometric and hematological measurements in Astyanax bimaculatus

ABSTRACT This study aimed to compare the body indexes and hematological characteristics between Astyanax bimaculatus males and females. Four hundred fish were randomly distributed into four polyethylene tanks (100 fish/unit) in a recirculation system and fed four times a day (3% of biomass). After 90 days, ten fish (five ♀ and five ♂) were removed to perform blood tests and to measure weight, height, total length, height/length ratio, condition factor and index determination: vicerosomatic (VSI), hepatosomatic (HSI), and gonadosomatic (GSI). The results showed a higher average weight (g) in females (12.32±0.71) compared to males (6.98±0.75), the same happened to height (cm) = (3.01±0.07) and (2.40±0.05), total length (cm) = (3.01±0.07) and (2.40±0.05), VSI (%) = (11.43±0.81) and (3.55±1.05), HSI (%) = (0.72±0.08) and (0.30±0.04), respectively. Mean corpuscular hemoglobin (pg) was higher in females (3.72±1.20) than in males (2.99±1.51). Regarding the number of thrombocytes (103.µL-1), there was an increase in males (25.71±3.91) compared to females (17.40±6.40).

摘要 本研究旨在比较双斑丽脂鲤（Astyanax bimaculatus）雌雄个体的身体指标与血液学特征。将400尾鱼随机分配至循环养殖系统中的4个聚乙烯养殖箱（每箱100尾），每日投喂4次，投喂量为鱼体生物量的3%。养殖90天后，采集10尾鱼（雌、雄各5尾）进行血液检测，并测量其体重、体高、全长、体高与全长之比、肥满度，以及脏体指数（vicerosomatic, VSI）、肝体指数（hepatosomatic, HSI）与性腺指数（gonadosomatic, GSI）。结果显示，雌性个体的平均体重（单位：g）为12.32±0.71，显著高于雄性的6.98±0.75；体高（单位：cm）、全长（单位：cm）、脏体指数（%）、肝体指数（%）亦呈现相同趋势，具体数值分别为：体高（3.01±0.07）与（2.40±0.05），全长（3.01±0.07）与（2.40±0.05），脏体指数（11.43±0.81）与（3.55±1.05），肝体指数（0.72±0.08）与（0.30±0.04）。平均红细胞血红蛋白含量（单位：pg）雌性为3.72±1.20，高于雄性的2.99±1.51。关于血小板数量（单位：10³·μL⁻¹），雄性为25.71±3.91，高于雌性的17.40±6.40。