According to the importance of vitamin B₆ (pyridoxine) as a water-soluble vitamin on the physiological conditions of aquatic animals, the present study aimed to investigate effects of different concentrations of this vitamin in recycle system culture water on the Nile tilapia (Oreochromis niloticus). Treatments including 0 (control), 10, 20, 30, and 40 mg L⁻¹ vitamin B₆ were adjusted in triplicate recirculating systems. Each of the experimental tanks (100 L) was stocked 15 fingerling Nile tilapia during 60-day experimental period. According to the findings, weight gain in treatments of 30 and 40 mg L⁻¹ pyridoxine was significantly higher than the other treatments while blood cortisol hormone in the treatment of 40 mg L⁻¹ was significantly highest among the treatments. In addition, mid-intestine trypsin activity in the treatment of 40 mg L⁻¹ was significantly higher than the other treatments. The histological analysis of the intestine showed that the number of mucus-secreting cells significantly decreased in treatments of 30 and 40 mg L⁻¹. Our findings here suggest that pyridoxine can possibly be absorbed by the Nile tilapia’s body through culture water and it seems 20–30 mg L⁻¹ pyridoxine in the culture water is the optimal concentration for the Nile tilapia juveniles in recycle system culture.

根据维生素B ₆（吡rid醇）作为水溶性维生素对水生动物生理状况的重要性，本研究旨在研究循环系统培养水中不同浓度的这种维生素对尼罗罗非鱼（Oreochromis niloticus）的影响。）。在三重循环系统中调整了包括0（对照），10、20、30和40 mg L ^-1维生素B _6的处理。在60天的实验期间，向每个实验缸（100 L）放养15只鱼种尼罗罗非鱼。根据发现，在30和40 mg L ^-1的治疗中体重增加吡ido醇显着高于其他治疗，而血液皮质醇激素在40 mg L ^-1的治疗中显着最高。另外，在40mg L ^-1的治疗中肠中胰蛋白酶活性显着高于其他治疗。肠道的组织学分析表明，在30和40 mg L ^-1的处理中，黏液分泌细胞的数量显着减少。我们的发现表明吡ido醇可能通过培养水被尼罗罗非鱼的身体吸收，并且培养水中的20–30 mg L ^-1吡ido醇似乎是循环系统培养中尼罗罗非鱼幼鱼的最佳浓度。