Preparation and Characterization of Chitosan Nanoparticles and their Effects on Growth, Immunity and Body Composition of Silver Carp (Hypophthalmichthys molitrix)

Abstract

A 3 months feeding experiment was designed to study the comparative effects of chitosan and its nano form on growth , immunity and body composition of silver carps Hypophthalmichthys molitrix under labo ratory condition. Chitosan nanoparti cles (CNP) of the size ran ged between 25.6 1 to 34.41 nm were prepared throu gh ionotropi c ge lation method . Uniform sized silver carps, after acc limatization were distributed into three groups. Group 1 was fed 35% protein basal di et; whereas the other two groups, Group-2 and Group-3 were offered chitosan and chitosan nanoparticl es suppl emented diet respectively at the same rate i.e. 5.0 g/kg. The whole experiment was conducted under semi-static condition in 9 rectangular glass aquaria at a stocking density of 2 giL. No mortality was observed throughout the feeding trial. At the end of the experiment, fish fed chitosan nanoparticles in the diet showed significantl y hi gh (P<O.OOl) % weight gain (WG) and % specifi c growth rate (SGR) as compared to other groups. Also the % feed conversion efficiency (FCE) was significantly higher (P<O.Ol) in fish fed diet supplemented w ith CNP. However, no significant difference was observed in growth performances and % FCE of fish fed basal and chitosan enriched diet. Proximate analysis revealed that muscles fats % content was significantly lower (P<0.05) in the fish fed chitosan supp lemented diet. However, muscle proteins % and moisture% contents were same in all groups wh ile % ash was significantly hi gher (P < 0.01) in muscles of fish fed ch itosan and CNP supplemented diets. High red blood cells (RBC's) count and hemoglobin (Hb) level was observed in fish fed chitosan and CNP supplemented diet. An aspartate aminotransferase (AST) and blood glucose leve l were significantly high in fish fed basal diet as compared to other diets. Moreover, plasma chol esterol level was considerabl y low (P<0.05) in fish reared on a chitosan supplemented di et as compared to CNP enriched and basal diets. Fish fed chitosan and chitosan nanoparticles in the diet showed better immune response after post challenged with Escherichia coli. Therefore, WBCs count, lysozyme activity, plasma protein and immunoglobulin were signiflcantly higher in fish fed CNP supplemented diet. The results clearly indicate the positive effect vi of CNP as growth and immunostimul ant. The Increase in % FCE after CNP suppl ementation in the diet reduced the feed cost along with th at low glucose level, AST activity suggested protective action of CNP against stresses and toxicity in the envi ro nment.