| The purpose of this study was to study the effects of different levels of astaxanthin on the growth,body color and antioxidant function of Paramisgurnus dabryanus.450 paramisgurnus dabryanus of(3.01±0.10)g were randomly divided into 5 groups,with 3 replicates in each group and 30 in each.The basic feed(control group)and the experimental feed with 50,100,150 and 200 mg/kg astaxanthin were fed respectively.After feeding for 8 w,sample isselected and to be tested.The results indicated that:1、The final weight,average weight gain rate and specific growth rate of the Paramisgurnus dabryanus increased significantly with the increase of astaxanthin(P<0.05),when the additive level of astaxanthin was 50 to 200 mg/kg,it was significantly higher than the control group(P<0.05),there was no significant difference between the groups.The highest level of astaxanthin was reached when the additive amount of astaxanthin was 100 mg/kg(P<0.05);The feed efficiency and protein efficiency of loach increased with the increase of astaxanthin.When astaxanthin was added at 100 mg/kg to 200 mg/kg,the feed efficiency and protein efficiency of Paramisgurnus dabryanus were significantly higher than those of control group(P<0.05).There was no significant difference between the groups.The highest level of astaxanthin was reached when the additive amount of astaxanthin was 100 mg/kg(P<0.05).When the addition level of astaxanthin was 50-200 mg/kg,the protein content of the components of Paramisgurnus dabryanus body in large scales increased with the increase of astaxanthin level,and was significantly higher than that of the control group(P<0.05).The addition group of 100-200 mg/kg was significantly higher than the control group and the group of 50 mg/kg(P<0.05).There was no significant difference between crude fat and crude ash(P>0.05).2、The carotenoids contentsin head,fin,skin and muscle presented a rised with the increasing levels of astaxanthin,when the additive level of astaxanthin was 100 to 200 mg/kg,it was significantly higher than the control group and 50 mg/kg group(P<0.05),the highest level of astaxanthin was reached when the additive amount of astaxanthin was 150-200 mg/kg(P<0.05)However,the tyrosinase(Tyr)contents in various tissues decreased,with the increasing levels of astaxanthin,and the Tyr contents of liver was significantly lower than that in the control group when the addition level was 150-200 mg/kg(P<0.05).The Tyr contents of muscle and skin significantly lower than that in the control group when the addition level was 50-200 mg/kg(P<0.05),the Tyr contents of intestinal tract showed no significant difference.3、With the astaxanthin addition increased,the activity of T-SOD in the livers,intestines,muscles and skin of large scales appears to increase.When the addition level of astaxanthin is 50-200 mg/kg,all of them were significantly higher than the control group(P<0.05),in which the highest level(P<0.05)was reached when the addition level was 100-200 mg/kg,and there was no significant difference between the groups.With the astaxanthin addition increased,the activity of CAT in livers,intestines,muscles and skin increased : when the addition level of astaxanthin was 50-200 mg/kg,the CAT activity of liver was significantly higher than that of control group(P<0.05).When the addition level of astaxanthin was 50-200 mg/kg,the intestinal CAT activity was significantly higher than that of the control group(P<0.05);When the addition level of astaxanthin was 50-200 mg/kg,the muscle CAT activity was significantly higher than that of the control group(P<0.05);The CAT activity was significantly higher in the skin than in the control group(P<0.05),when the addition level of astaxanthin was 100-200 mg/kg.The MDA content in each tissue decreased with the increase level of astaxanthin addition,when the addition level of astaxanthin was 50-200 mg/kg,The MDA activity of liver and muscle was significantly higher than that of control group(P<0.05).When the addition level of astaxanthin was 100-200 mg/kg,the MDA activity of intestines and skin was significantly higher than that of control group(P<0.05).The GSH content increased with the increase of With the astaxanthin addition.When the addition level of astaxanthin is 50-200 mg/kg,all of them were significantly higher than the control group(P<0.05),in which the highest level(P<0.05)was reached when the addition level of astaxanthin was 100-200 mg/kg,and there was no significant difference between the groups.The activity of GSH-PX increased with the increase of With the astaxanthin addtion.When the addition level of astaxanthin is 50-200 mg/kg,all of them were significantly higher than the control group(P<0.05),in which the highest level(P<0.05)was reached when the addition level of astaxanthin was 100-200 mg/kg,and there was no significant difference between the groups.4、The relative expression of Nrf2 mRNA in the livers of large scales appears to be increasing with the increase in the level of addition of astaxanthin.When the addition level of astaxanthin is 50-200 mg/kg,The relative expression of Nrf2 mRNA in liver tissue was significantly higher than that in control group(P<0.05).When the addition level of astaxanthin is 100-200 mg/kg.The relative expression of Nrf2 mRNA in liver tissue was significantly higher than that in control group and 50 mg/kg group(P<0.05),and there was no significant difference between the three groups.The relative expression of Keap1 mRNA in the livers of large scales appears to be reduced with the increase in the level of addition of astaxanthin,when the addition level of astaxanthin is 50-200 mg/kg was significantly lower than that in control group(P<0.05).When the addition level of astaxanthin is 100-200 mg/kg,the relative expression of Keap1 mRNA in liver tissue was significantly lower than that in control group and 50 mg/kg group(P<0.05),and there was no significant difference between the three groups.The relative expression of Maf mRNA in the livers of large scales appears to be reduced with the increase in the level of addition of astaxanthin: When the addition level of astaxanthin is 50-200 mg/kg,The relative expression of Maf mRNA in liver tissue was significantly lower than that in control group(P<0.05).When the addition level of astaxanthin is 100-200 mg/kg,the relative expression of Maf mRNA in liver tissue was significantly lower than that in control group and 50 mg/kg group(P<0.05),and there was no significant difference between the three groups.Under the current conditions,astaxanthin addition can promote the growth performance,body color and antioxidant ability.There were significant difference of all astaxanthin addition groups.In conclusion the suitable astaxanthin addition level in feed is 100-200 mg/kg. |
PDF Full Text Request