Food preference and growth of grass carp, Ctenopharyngodon idella (Cuvier and Valenciennes, 1844) fed some aquatic and terrestrial plants

The present study was carried out to examine 6 plants including aquatic and terrestrial plants on food preference and growth of grass carp. 7 experimental treatments with three replicates were considered. The experimental treatments were ponds containing T-1: M. spicatum, T-2: C. demersum, T-3: A. filiculoides, T-4: L. minor, T-5: C. dactylon, T-6: M. sativa and T-7: M. Spicatum + C. demersum + A. filiculoides + L. minor + C. dactylon + M. sativa. 12 grass carps (20 g) were added to each experimental pond. After 5 months, the fish body composition was assessed. According to results, the higher values of fish weight gain rate were obtained in treatments T-4 (3.13 g), T-6 (2.93 g) and T-1 (2.95 g) compared to other experimental groups (p<0.05). Also, the highest percentage of body protein and lipid content were observed in T-4 and T-1. In addition, the biomass and percentage of examined plants decreased after delivery of grass carps to each pond over the course of the experiment, but higher decreases were recorded for T-4 and T-1. The mean values of relative growth rate were higher in T-4 and mixture of all plants (p<0.05). Also, the highest fish biomass was recorded in T-1 and T-4 (p<0.05). In conclusion, our results showed that T-4 and T-1 have higher adaptability compared to other examined plants in the present study and these two plants could be used for feeding grass carp in aquaculture.