Effects of supplemented garlic (Allium sativum) extract on growth performance, feed and culture water quality of rainbow trout (Oncorhynchus mykiss) under ammonia stress in the recirculating aquaculture system

This research was conducted to determine the effects of garlic extract as feed supplement on the growth performance, feed and culture water quality of rainbowtrout (Oncorhynchus mykiss) under stress ammonia. A total of 120 healthy fish with a weight of 18.37 ± 1.43 g and length of 12.27 ± 0.52 cm were reared in twelve 50-Lplastic tanks. Rainbow trout were fed diets containing 0% (control), 0.5% (A1), 1% (A2) and 1.5% (A3) garlic (Allium sativum) extract for 60 days. The results of statistical analysis showed that the final weight and weight gain were significantly higher in fish fed garlic extract supplementation than control treatment. The highest amount of final weight was obtained in A2 (129.73 ± 17.26 g) and the lowest in control (92.14 ± 8.74 g). There was a statistically significant difference in the amount of feed conversion ratio (FCR) between different treatments, so that was obtained the lowest in A2 and the highest in control. At the end of the experiment, quantitative and qualitative water factors were analyzed. The experimental treatments had the highest ammonia and nitrate amount compared to the control treatment in culture water. At the end of the study, the results indicated that the growth and feed indices of fish were significantly higher among garlic-supplemented groups compared to the control group, but this extract does not affect the water quality

Keywords:

Oncorhynchus mykiss , Garlic extract , Growth , Water quality , Recirculating aquaculture system