Effect of mint powder, Mentha longifolia, and vitamin D administration on growth indices of juvenile rainbow trout, Oncorhynchus mykiss

Numerous studies have shown that herbs can be used as growth stimulants in aquaculture. This study aimed to investigate the effect of combined consumption of mint powder and vitamin D on the growth and health of juvenile rainbow trout, Oncorhynchus mykiss. For this purpose, a total of 200 juvenile rainbow trout were divided into four groups and treated for 60 days as follows: The 1st group (control) used a standard diet; the 2nd group had 1.5% mint powder in their diet; The 3^rd group having an additional amount of 120 mg/kg of vitamin D in their diet; The 4^th group fed a diet having mint and vitamin D supplements as 2^ed and 3^rd groups. All groups growth and health indices viz. condition factor, hepatic steatosis index, visceral sensitivity index, spleen somatic index, weight gain percentage, specific growth rate, feed conversion ratio, satiety index, food conversion efficiency, and protein efficiency ratio were measured and compared on days 20, 40, and 60. The results revealed that the use of mint powder in the juvenile rainbow trout diet not only had no remarkable effect on the growth and health of fish but also improved their growth. In addition, all the analyzed indications of the mint powder group outperformed than the vitamin D group.