壳聚糖对淡水白鲳生长和非特异性免疫功能的影响

Effects of dietary chitosan on growth and non-specific immunity of freshwater spadefish(Colossoma brachypomum)

配制添加不同浓度壳聚糖（0、0.2%、0.4%、0.6%、0.8%、1.0%）的6组实验饲料,网箱养殖淡水白鲳（Colossoma brachypomum）（82.26±5.13）g 60 d,探讨壳聚糖对淡水白鲳生长、非特异性免疫功能的影响和其在饲料中的适宜添加量。结果表明：0.6%组末体重、特定生长率、饲料效率和蛋白质效率显著高于0、0.2%、0.4%和1.0%组（P〈0.05）;0.6%、0.8%和1.0%组脏体比显著低于0、0.2%和0.4%组（P〈0.05）;0.6%、0.8%和1.0%组肝体比显著低于0组（P〈0.05）;0.6%组溶菌酶活性最高,显著高于0和0.2%组（P〈0.05）;0.6%组超氧化物歧化酶活性最高,显著高于其它组（P〈0.05）;0.6%组酸性磷酸酶活性显著高于0和0.2%组（P〈0.05）;用嗜水气单胞菌对淡水白鲳进行攻毒后的14 d内,0.6%、0.8%和1.0%组的死亡率显著低于0组（P〈0.05）。综合各项实验指标,淡水白鲳饲料中添加适量的壳聚糖能提高其生长性能、饲料利用率、非特异性免疫功能以及抗嗜水气单胞菌感染能力,适宜添加量0.6%~0.8%。

Freshwater spadefish（Colossoma brachypomum） with initial weight of（82.26±5.13） g in netcage were fed with diets supplemented with different levels of chitosan（0,0.2%,0.4%,0.6%,0.8%,1.0%） for 60d to examine the effects of dietary chitosan on growth and non-specific immunity of freshwater spadefish,and the appropriate dosage of chitosan for dietary supplementation.The results showed that the final weight,specific growth rate（SGR）,feed efficiency ratio（FER） and protein efficiency ratio（PER） of group 0.6% was highest,significantly higher than groups 0,0.2%,0.4% and 1.0%（P0.05）.Hepatosomatic indexes（HSI） of groups 0.6%,0.8% and 1.0% were significantly lower than groups 0,0.2% and 0.4%（P0.05）.Viscerosomatic index（VSI） of groups 0.6%,0.8% and 1.0% were significantly lower than group 0（P0.05）.Activity of lysozyme（LZM） of group 0.6% was highest,significantly higher than groups 0 and 0.2%（P0.05）.Activity of super oxide dismutase（SOD） of group 0.6% was significantly higher than that of other groups（P0.05）.Activity of acid phosphatase（ACP） of group 0.6% was higher than groups 0 and 0.2%（P0.05）.Mortality of groups 0.6%,0.8% and 1.0% were significantly lower than group 0（P0.05） after being challenged with live Aeromonas hydrophila in 14 d.Thus adding chitosan in freshwater spadefish feed appropriately can improve their growth performance,feed utilization,non-specific immune function and the resistance to infection with Aeromonas hydrophila.The supplement of 0.6%～0.8% chitosan was optimum for the feed of freshwater spadefish.