Abstract

TORRES, José  and  FAJARDO, Carlos. Prophylactic treatments anti-saprolegniasis to improve embryo survival in eggs of rainbow trout (Oncorhynchus mykiss). Zootecnia Trop. [online]. 2011, vol.29, n.2, pp.235-239. ISSN 0798-7269.

During the incubation of eggs of Oncorhynchus mykiss, one of the biggest problems that arise is the attack caused by opportunistic fungi in the water. Fungi belonging to the genus Saprolegnia are the most common pathogens that attack the eggs of salmon. Saprolegniasis manifested by forming a coating of hyphae that are located on dead eggs, moving quickly to the nearest healthy eggs, cause losses between 20 and 100%. Implementing preventive health measures and in aquaculture, play an important role in preventing and controlling disease, preventing pathogens from attacking eggs, larvae and fish healthy. To study the effect of prophylactic treatments on the incidence of saprolegniasis and hatching survival of eggs of O. mykiss, in culture facilities three treatments were implemented: manual cleaning, formalin (250 ppm) and salt (NaCl, 30,000 ppm). Once hatched larvae in each bioassay determined the survival rate. Later the larvae were taken under each treatment and larval mortality was determined after 15 days. Prophylactic treatments able to improve between 10 and 20% embryonic survival to hatching in the control. The salt and formalin treatments led to a better response. No significant differences (P>0.05) between treatments in terms of larval mortality at 15 days of hatching. The salt treatment is recommended, not only for the results obtained in relation to embryonic and larval survival, but also because of its low cost and low toxicity to both fish and humans

Keywords : rainbow trout; Oncorhynchus mykiss; Saprolegnia; saprolegniasis.