Brown trout is an environmental freshwater sentinel species and is economically important for recreational fishing and aquaculture. Despite that, there is limited knowledge regarding morpho-physiological variations in adults throughout the reproductive cycle. Thus, this study aimed to analyze the fitness and gonadal maturation of cultured adult brown trout in four reproductive phases (spawning capable—December, regressing—March, regenerating—July, and developing—November). The systematic evaluation of males and females was based on biometric, biochemical, and hormonal parameters, along with a histomorphological grading of gonads and the immunophenotype location of key steroidogenic enzymes. The total weight and lengths reached the lowest levels in December. Gonad weights were higher in December and November, while the opposite pattern was found for liver weights. The lowest levels of cholesterol and total protein were also noted during those stages. The 11-ketotestosterone (11-KT) and testosterone (T) for males, and estradiol (E2) and T for females, mostly explained the hormonal variations. The immunohistochemistry of cytochrome P450c17 (CYP17-I), aromatase (CYP19), and 17β-hydroxysteroid dehydrogenase (17β-HSD) showed sex and site-specific patterns in the distinct reproductive phases. The sex- and season-specific changes generated discriminative multi-parameter profiles, serving as a tool for environmental and aquaculture surveys.

中文翻译：

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评估褐鳟四个关键繁殖阶段适应性和性腺成熟度的多参数组合

鳟鱼是一种环境淡水定点物种，对休闲捕鱼和水产养殖具有重要的经济意义。尽管如此，关于整个生殖周期中成年人形态生理变化的知识仍然有限。因此，本研究旨在分析养殖成年褐鳟在四个生殖阶段（产卵能力-12月，退化-3月，再生-7月和发育-11月）的适应性和性腺成熟度。对男性和女性的系统评价是基于生物特征，生化和激素参数，以及性腺的组织形态学分级和关键类固醇生成酶的免疫表型位置。总重量和长度达到了12月的最低水平。在12月和11月，Gonad权重较高，而肝脏重量却发现了相反的模式。在这些阶段中，胆固醇和总蛋白的含量也最低。男性的11-酮睾丸酮（11-KT）和睾丸激素（T），女性的雌二醇（E2）和T可以解释激素的变化。细胞色素P450c17（CYP17-I），芳香化酶（CYP19）和17β-羟类固醇脱氢酶（17β-HSD）的免疫组织化学在不同的生殖阶段表现出性别和位点特异性模式。性别和季节特定的变化产生了可辨别的多参数配置文件，可作为环境和水产养殖调查的工具。大部分解释了荷尔蒙的变异。细胞色素P450c17（CYP17-I），芳香化酶（CYP19）和17β-羟类固醇脱氢酶（17β-HSD）的免疫组织化学在不同的生殖阶段表现出性别和位点特异性模式。性别和季节特定的变化产生了可辨别的多参数配置文件，可作为环境和水产养殖调查的工具。大部分解释了荷尔蒙的变异。细胞色素P450c17（CYP17-I），芳香化酶（CYP19）和17β-羟类固醇脱氢酶（17β-HSD）的免疫组织化学在不同的生殖阶段表现出性别和位点特异性模式。性别和季节特定的变化产生了可辨别的多参数配置文件，可作为环境和水产养殖调查的工具。