عنوان مقاله [English]
In the present study, the effect of cinnamon (Cinnamomum verum) on growth performance and some immune factors of rainbow trout (Oncorhynchus mykiss) was investigated at two levels in high- and low-carbohydrate diets. A total of 360 rainbow trout with an average initial weight of 16.12 ± 1.33 g (mean ± SD) were fed by six diets including Diet1 (low carbohydrate level; 20 % carbohydrate), Diet2 (low carbohydrate level and 3 % cinnamon), Diet3 (low carbohydrate level and 5 % cinnamon), Diet4 (high carbohydrate level; 30 % carbohydrate), Diet5 (high carbohydrate level and 3 % cinnamon), and Diet6 (high carbohydrate level and 5 % cinnamon) for 56 days. The results revealed that the effect of diet containing carbohydrates and cinnamon on the final weight and weight gain was significant and the highest final weight and weight gain were observed in diet 2 (low carbohydrates and 3% cinnamon) and Diet 3 (low carbohydrates and 5% cinnamon) with no significant difference with Diet 6 (high carbohydrate and 5% cinnamon). The results of hematopoietic indices related to white blood cells and their differential count in rainbow trout showed no significant difference between the treatments in the number of white blood cells, monocytes, basophils, neutrophils, and eosinophils. However, the lymphocyte level was affected by experimental treatments and the highest level was observed in fish fed by Diet 3. There was no significant difference in lysozyme activity, immunoglobulin, and the complement system. According to the results related to growth performance and some immune indicators, fish fed by Diets 2 and 3 had better performance than other treatments.