Monitoring and evaluation of environmental and directory risk factors affecting the occurrence of certain specific viral diseases at the SPF center of rainbow trout in Iran

The aim of this study was to monitor and evaluate the environmental and directory risk factors affecting the occurrence of some specific viral diseases in the region in the region of establishing a large-scale project of rainbow trout production of specific pathogens free (SPF) in the country in order to achieve the guidelines for managing and reducing the risks assessed in the pre-quarantine hall and the SPF center. For this purpose, after completing the questionnaire of physical and chemical indicators of pre-quarantine water inlet and outlet such as oxygen, temperature, pH, nitrite, nitrate, ammonium, ammonia and total bacteria were measured for 6 months from May to October 2017 according to the standard method. Also fish in the pre-quarantine hall were sampled to check for the possibility of infection with IPN, IHN and VHS viruses. The results showed that the average temperature, soluble oxygen, pH, nitrite, nitrate, ammonium, ammonia and total count water of the pre-quarantine hall entrance were respectively 17±1.55°C, 8.32±0.65 mg/l, 8.98±0.37 mg/l, 0.003±0.000 mg/l, 3.10±0.71 mg/l, 0.09±0.10 mg/l, 0.08±0.09 mg/l and 90.50±86.58 colony units per ml and outlet water were respectively 17.59±1.46°C, 8.20±0.62 mg/l, 8.18±0.35 mg/l, 0.040±0.040 mg/l, 3.74±1.14 mg/l, 0.09±0.07 mg/l, 0.08±0.07 mg/l and 784.50±1329.95 colony units per ml. The findings of this study indicate that in the process of producing rainbow trout of Specific Pathogens Free (SPF) from pre-breeder to breeder stage in pre-quarantine hall, there has been avoidance the entry of pathogens. And fluctuations in the physical and chemical indicators of water during the breeding period, the lack of a central oxygen generator, problems with the aeration system and the low flow of incoming water were identified as risk factors.