Effect of natural polymer chitosan on total immunoglobulin, hemoglobin concentration and resistance of rainbow trout (Oncorhynchus mykiss) against Aeromonas hydrophila

Rainbow trout (Oncorhynchus mykiss) is the main farmed cold water fish in Iran. This study was conducted to determine the effect of Chitosan as an immune stimulator on total immunoglobulin and blood hemoglobin concentration of rainbow trout and resistance against Aeromonas hydrophila infection. 900 rainbow trout (25± 0.1 g mean weight) after acclimated to laboratory conditions for two weeks divided into four groups in three replicates randomly. The fish were fed with different concentrations of Chitosan (0, 0.25, 0.5 and 1 percent of feed). Chitosan was solved in acetic acid (1%) and sprayed on a commercial feed pellet (FFT2) and fed the fish for eight weeks. All experimental groups were fed with control diet (without Chitosan) for three weeks later. Sampling was conducted at 0, 2, 4, 6, 8 and 11 weeks of the trial and total immunoglobulin and blood hemoglobin concentration were measured. All trial were injected (IP) with a pathogenic strain of Aeromonas hydrophila at a level of 107 CFU/ml at the end of 8 week. After statistical analyzing data with SPSS softwar, Results showed that adding Chitosan at 0.25 percentage of feed could significantly (P