The effect of anaerobic fermentation of cow manure on culture of Rutilus frisii Kutum and comparison of survival and growth factors versus traditional feeding

Rutilus firisii kutum is one of the important fish in Caspian Sea that has significant economical role to the region. The overall objective of the project is to compare the growth and survival of Rutilus frisii Kutum larvae under conventional conditions and conditions under use of organic fertilizer by anaerobic fermentation or slurry. This study was conducted in nine 1.7 hec pounds with 3 treatments with stocking densities of 1.7 million fish larva at Dr Yousefpoor Center at Siakal Village, 32km far from city of Rasht in North of Iran. The first treatment considered as control using concentrated food and grinded kilka fish. In the second treatment, the pound was supplied only by slurry for 13 days followed by concentrated fish food. The third treatment started with slurry for 13 days followed by slurry and concentrated food together. The physical and chemical parameters of water, plankton, biometry of fish, growth indices were monitored weekly. The result indicated that production was 1.7 to 2 times higher in slurry than traditional treatment also the survival rate was 1.7 times higher in slurry treatment. Slurry with several active substances is more effective and can promote the growth of zooplanktons that is the food for larval stage of Rutilus frisi kutum. Nutritional contents of phosphorous, nitrogen, calcium, magnesium, potassium, protein and lipid after anaerobic fermentation were higher in slurry treatment than control. The blue-green algae density in slurry pounds was less than control