Comparison of Koi carp larvae growth performances fed with Urmia Lake Artemia (Artemia urmiana) nauplii from the decapsulated and non-decapsulated cysts

In this study, number of 180 koi fish larvae (0.2 g average weight) were fed with Lake Urmia Artemia nauplii in two treatments including nauplii from the decapsulated and non-decapsulated cysts for 60 days. The results showed that growth parameters and survival rate were significantly improved in koi fish fed with nauplii from decapsulated cyst(P< 0.05). Also, the fish larval weight was increased in nauplii from decapsulated (252.04%) compared to non-decapsulated (234.07%). FCR was 1.03 and 0.88 for the nauplii from the non-decapsulated and decapsulated cysts, respectively. The minimal survival rate was observed at encapsulated treatment (73%) than decapsulated treatment (84.1%). The results of nutritional value of Artemia Nauplii showed that that nauplii from a newly hatched freshly weighed the encapsulated cyst contained 9.8% protein and 1.8% fat which was lower than the nauplii from the decapsulated cysts (P< 0.05). Also, the hatching rate of cysts in decapsulated treatment (89.08%) was more than encapsulated (76.73%) samples (P< 0.05). In conclusion, decapsulated artemia cysts can significantly improve the growth performances and survival rates of koi larvae as an ornamental fish.