壳聚糖对俄罗斯鲟幼鱼生长性能及免疫功能的影响

在基础饲料中分别添加浓度为0对照组）、1.25、2.5、5、7.5和10 g/kg的壳聚糖，投喂12 g左右的俄罗斯鲟50d，每组设3个重复，每个重复30尾，研究不同浓度的壳聚糖对俄罗斯鲟（Acipenser gueldenstaedti）幼鱼的生长性能及免疫力的影响。结果表明，与对照组相比，添加2.5和5 g/kg的壳聚糖可显著提高俄罗斯鲟幼鱼的增重率和特定生长率，降低饲料系数（P < 0.05），而当添加量超过10 g/kg时会抑制其生长（P < 0.05）；1.25和2.5 g/kg组血清超氧化物歧化酶活性显著高于对照组（P < 0.05），其他试验组则显著低于对照组（P < 0.05）；2.5和5 g/kg组溶菌酶活性显著高于对照组，当壳聚糖添加量超过7.5 g/kg时则会抑制血清溶菌酶活性（P < 0.05）；1.25和5 g/kg组酸性磷酸酶活性、碱性磷酸酶活性和补体C3含量都显著高于对照组（P < 0.05）；各试验组IgM含量不受壳聚糖的影响，与对照组差异不显著（P>0.05）。在试验条件下，添加适量的壳聚糖能提高俄罗斯鲟幼鱼的生长性能，增强其免疫能力，以增重率、特定生长率及非特异性免疫为综合评价指标，壳聚糖添加量以2.5 g/kg为宜。

EFFECTS OF CHITOSAN ON GROWTH PERFORMANCE AND IMMUNITY OF JUVENILE RUSSIAN STURGEON (ACIPENSERGUELDENSTAEDTI)

A 50-day feeding trial was conducted to investigate the effects of dietary chitosan supplement on growth per-formance and immunity of juvenile Russian sturgeon (initial body weight of 12 g). In total, 540 fish were assigned to six groups (30 fish per replicate, triplicate experiments). The fish were fed basal experimental diets supplemented with different levels of chitosan:0 (control group), 1.25, 2.5, 5, 7.5 and 10 g/kg respectively. The results showed that the weight growth rate (WGR) and specific growth rate (SGR) in 2.5 and 5 g/kg groups were significantly higher than that in control group (P<0.05), whereas feed coefficient (FC) decreased significantly (P<0.05), but the growth in 10 g/kg group was inhibited. The superoxide dismutase (SOD) activity in 1.25 and 2.5 g/kg were significantly higher than that in control group (P<0.05), while the SOD activity in the other three groups were significantly lower than that in control group (P<0.05). Lysozyme (LZM) activity in serum of 2.5 and 5 g/kg groups increased significantly (P<0.05), while 7.5 and 10 g/kg groups were significantly lower than that in control group (P<0.05). The alkanlin phoshpatase (AKP) activity, acid phosphatase (ACP) activity and content of complement C3 in 1.25, 2.5, 5 g/kg groups were significantly higher than those in control group (P<0.05). No significant difference was observed on serum IgM in all supplementa-tion group (P>0.05). These results indicated that dietary chitosan supplementation can improve the growth perfor-mance and immunity in juvenile Russian sturgeon. Based on the WGR, SGR and non-specific immunity, the chitosan supplement in diets was suggested to be 2.5 g/kg for juvenile Russian sturgeon.