Abstract：
The present study investigated the best photoperiod for culturing pacu (Piaractus mesopotamicus) in recirculation aquaculture systems (RAS) based on its growth performance and hematological and oxidative stress responses. Juveniles (∼ 5 g) were subjected to five treatments (in triplicate): 24 L (light):0D (dark), 15 L: 09D, 12 L:12D, 9 L:15D, and 0 L:24D for 45 days. A total of 225 pacu individuals were randomly distributed among 15 tanks of 210 L (n = 15 per tank). Zootechnical, hematological (glucose, lactate, hematocrit, and hemoglobin), and antioxidant and oxidative stress parameters (glutathione S-transferase (GST), total antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were analyzed. The zootechnical parameters (e.g., weight gain, Fulton\'s condition factor, and specific growth rate) were better and worse with 9 L:15D and 24 L:0D photoperiods, respectively. The hepatosomatic index was higher and lower in the 0 L:24D and 9 L:15D photoperiods. Blood lactate levels and antioxidant and oxidative stress responses were increased in the longest photoperiods (15 L:9D and 24 L:0D). In contrast, the treatments that showed lower oxidative damage (liver, gills, brain, and muscle) were 9 L:15D and 12 L:12D. In conclusion, manipulating artificial light is one way to improve fish growth and health, where the best photoperiod for pacu farming in RAS is 9 L:15D.
摘要：
本研究根据其生长性能以及血液学和氧化应激反应，研究了在再循环水产养殖系统（RAS）中培养pacu（Piaractusmesopotamicus）的最佳光周期。幼鱼（〜5g）进行了五次处理（一式三份）：24L（光）：0D（暗），15L:09D,12L:12D,9L:15D,和0L：24D持续45天。总共225个pacu个体随机分布在15个210L的坦克中（每个坦克n=15）。Zootechnical,血液学（葡萄糖，乳酸，血细胞比容,和血红蛋白），以及抗氧化剂和氧化应激参数(谷胱甘肽S-转移酶(GST)，对过氧自由基（ACAP）的总抗氧化能力，和脂质过氧化（LPO）进行了分析。动物园技术参数(例如，体重增加,富尔顿的条件因子，和特定生长速率）在9L：15D和24L：0D的光周期下越来越好，分别。在0L：24D和9L：15D光周期中，肝细胞指数较高和较低。在最长的光周期（15L：9D和24L：0D）中，血液乳酸水平以及抗氧化剂和氧化应激反应增加。相比之下,显示较低氧化损伤的治疗方法(肝脏，ill,大脑,和肌肉）分别为9L：15D和12L：12D。总之,操纵人造光是改善鱼类生长和健康的一种方法，在RAS中，pacu养殖的最佳光周期是9L：15D。
