| A50-d feeding trial was carried out to investigate the effects of dietarychitosan on growth performance and body composition of juvenile Oncorhynchusmykiss (98.26±0.25g). Five isonitrogenous and isoenergetic diets were formulated byadding0(D0, control group),0.25%(D1),0.50%(D2),1.00%(D3) and2.00%(D4)chitosan to the basal diet. Results showed that: weight gain rate (WGR) and specificgrowth rate (SGR) increased whereas feed conversion ratio (FCR) decreasedsignificantly (P<0.05) with chitosan addition. No significant differences were foundamong chitosan-supplemented groups (P>0.05). Viscerosomatic index (VSI) decreasedwith dietary chitosan supplementation (P<0.05). However, there were no statisticaldifferences in hepatosomatic index (HSI), spleensomatic index (SSI), condition factor(CF) or survival ratio (SR)(P>0.05). Lipid content in whole fish, muscle and liver weredecreased obviously by dietary chitosan (P＜0.05), while no change existed inmoisture and protein contents (P>0.05). Growth performance was enhanced by dietarychitosan. Under the conditions of this experiment, we can conclude that the optimumlevel of chitosan in diet of rainbow trout (98.26±0.25g) was0.50%using growthperformance as the response criteria.To determine the effect of dietary chitosan levels on antioxidantcapacity and non-specific immunity of juvenile Oncorhynchus mykiss (98.26±0.25g),fishs were fed with the diets for50d which supplemented with0(D0, control group),0.25%(D1),0.50%(D2),1.00%(D3) and2.00%(D4) chitosan. Results showed that:total antioxidant capacity (T-AOC) of D4group was significantly higher than that of thecontrol and D1group(P＜0.05) and no differences were found among other groups(P>0.05). Anti-superoxide anion activity of D4group was significant higher than thecontrol group (P＜0.05), no differences were found among other groups (P>0.05).Superoxide dismutase (SOD) was not affected by dietary chitosan (P>0.05). Haemoglobin (Hb) content decreased with chitosan addition, and the top value wasobserved in D1group. However, haemoglobin content of D4group was obviously lowerthan D1, D2and D3groups (P＜0.05). Nitric oxide (NO) concentration decreasedsignificantly (P<0.05) with chitosan addition. Alkaline phosphatase (ALP) activity inserum of D3and D4groups was decreased significantly (P＜0.05) and there were nodifferences among other groups (P>0.05). Serum acid phosphatase (ACP) activitydecreased as dietary chitosan supplementation level increased (P＜0.05), whilelysozyme (LZM) activity was increased (P＜0.05). Serum total protein (TP)concentration was not affected by dietary chitosan (P>0.05). Under the conditions ofthis experiment, we can conclude that the optimum level of chitosan in diet of rainbowtrout (98.26±0.25g) was0.50%using antioxidant capacity and non-specific immunity asthe response criteria.An8-week feeding trial was carried out to investigate the effects ofdietary chitosan on growth performance, lipid deposition and lipidemic of juvenilePlatichthys stellatus (46.03±0.11g). Five isonitrogenous and isoenergetic diets wereformulated by adding0(D0, control group),0.25%(D1),0.50%(D2),1.00%(D3) and2.00%(D4) chitosan to the basal diet. Results showed that: weight gain rate (WGR) andspecific growth rate (SGR) of trial groups were higher than the control group, and thesignificance was found between D4and the control group(P＜0.05. Daily feed intake(DFI) was significantly increased by dietary chitosan(P＜0.05), whereas viscerosomaticindex (VSI) was obviously decreased (P＜0.05). No statistical differences was found infeed conversion ratio (FCR) and survival ratio (SR)(P>0.05). Lipid contents of trialgroups in whole fish were lower than control group, significant differences was foundbetween D4group and control group(P＜0.05). Muslce lipid of D4group wassignificant lower than other groups(P＜0.05), while no change occurred in liver lipidcontent(P>0.05). Serum triglyceride (TG) and HDL-cholesterol (HDL-C) concentrationdecreased with chitosan addition, while no change occurred in LDL-cholesterol (LDL-C)concentration. In this experiment, using WGR and antioxidant capacity of juvenilePlatichthys stellatus as the response criteria, we can conclude that the optimum level ofchitosan in diet of starry flounder (46.03±0.11g) was1.00%.A study was conducted to determine the effect of dietary chitosan levels on antioxidant capacity and non-specific immunity of juvenile Platichthys stellatus(46.03±0.11g). Five isonitrogenous and isoenergetic diets which supplemented with0(D0, control group),0.25%(D1),0.50%(D2),1.00%(D3) and2.00%(D4) chitosanwere each fed to triplicate groups of starry flounder (46.03±0.11g) for8weeks. Resultsshowed that: Total antioxidant capacity (T-AOC) of D4group and anti-superoxide anionactivity of D2group were significant higher than the control group (P＜0.05), nodifferences was found among other groups (P>0.05). Activities of superoxide dismutase(SOD) and glutathione peroxidase (GSH-PX) in serum were elevated significantly (P＜0.05), and the top value was observed in D3or D2group respectively, activities of thesetwo enzymes were depressed by higher levels of chitosan. Ceruloplasmin (CP) was notaffected by dietary chitosan (P>0.05). Serum albumin (Alb) and total protein (TP)concentration increased whereas acid phosphatase (ACP) decreased significantly withchitosan addition(P＜0.05). Lysozyme (LZM) activity was increased with chitosanaddition, and the top value was observed in D2group. Haemoglobin (Hb) content wasnot affected by dietary chitosan (P>0.05). Under the conditions of this experiment, wecan conclude that the optimum level of chitosan in diet of starry flounder (46.03±0.11g)was0.50%using antioxidant capacity and non-specific immunity as the responsecriteria. |
