Effect of EncapsulatedLactobacillus bulgaricuson Innate Immune System and Hematological Parameters in Rainbow Trout (Oncorhynchus mykiss), Post-Administration of Pb

The present study was conducted to investigate the effects of probiotic and encapsulatedLactobacillus bulgaricuson hematological and immunological factors after lead toxicity in rainbow trout (Oncorhynchus mykiss). Two hundred and forty fish weighing about 16 +/- 3.8 g were divided randomly in to four groups including two groups which were fed by a diet containing ~ 10(8) CFU g(-1)Lactobacillus bulgaricusand encapsulatedLactobacillus bulgaricusbacteria and also the third group diet withoutLactobacillus bulgaricus. After 45 days, in addition to probiotic (~ 10(8) CFU g(-1)), 500 mu g kg of lead nitrate was added to the food of the three groups for 21 days. The fourth group (control) was first fed to the normal diet for 45 days then exposed to Pb. Blood samples were collected at days 45, 52, 59, and 66, and hematological and some immunological parameters were assessed. Results showed that hemoglobin, red blood cells, white blood cells, and lysozyme activity in the two probiotics groups were increased significantly up to 45 day (P < 0.05), but followed by a decreasing trend by adding Pb. Complement and bactericidal activity were enhanced significantly in thebulgaricusgroup (P < 0.05). Respiratory burst activity at day 45 in groupbulgaricushad significant increase (P < 0.05) and decreased in all groups particularly after Pb exposure (P < 0.05). The achieved data shows that microencapsulation of probiotics with alginate-chitosan may be a suitable method to improve the fish condition against heavy metal.