Effect of nanosilver particles on hatchability of rainbow trout (Oncorhynchus mykiss) egg and survival of the produced larvae

Effect of nanosilver particles was studied on the hatchability of rainbow trout (Oncorhynchus mykiss) egg and survival of the produced larvae at about 12ºC. In the first experiment the water-based nanosilver particles was used at concentrations of 0.5, 1, 2 and 4 mgL^-1 for 30 minutes per day starting 24 hour post egg incubation until the hatching time. The mean percentage of hatchability reached in 27.6±0.2, 38.2±0.1, 41.6±0.4 and 48.6±1.5 in troughs treated with 0.5, 1, 2 and 4 mgL^-1 nanocid, respectively compared with 64.7±0.2 % for trough treated with malachite green at 2 mgL^-1 as positive control (P0.05). These data suggest a possible application of nanosilver particles in aquaculture sector particularly using incubator troughs of trout containing nanosilver materials

Production of immunized eggs against Salmonella enteritidis and Escherichia. coli K99

Escherichia.coli K99 and Salmonella enteritidis are two main causes of diarrhea in calves. For prevention of diseases caused by these two microorganisms, many methods such as vaccination and passive transmission of immunity could be used. In recent years the concept of using immunized eggs in the feed of sensitive calves has been considered. In order to prepare antigen, E.coli K99 and Salmonella enteritidis were killed by adding 1% formalin solution after culture on Nutrient Broth media (Merck Co.) for 24 hours. The antigens were purified and made ready to use after washing with PBS for three times. The amount of antigen in each dosage was set based on 200μg/ml protein and 1×109 CFU/ml. The hens were injected subcutaneously 4 times in 2 weeks intervals with Freund's complete adjuvant (Sigma Co.) in the first two injections and Freund's complete adjuvant (Sigma Co.) in the second two injections. Sampling was also done in two weeks intervals and then antibody titers in serum and egg samples were assayed by agglutination method. The results of the present study indicated that the immunized eggs were hyper immune and could be used for stimulation of the immune system in one day old calves