| The present study was conducted to evaluate the influence of compound Chinese herbal medicine on the growth performance and immune function of blunt snout bream(Megalobrama amblycephala).Fish were fed with basic diet containing three different Chinese herbal medicines,Calendula officinalis,Eucommia ulmoides and Astragalus propinquus.There were seven groups,groups A1 and A2 were fed with the diet containing 2% and 4% compound preparation A(mainly composed of Calendula officinalis,supplemented by Eumoia ulmoides and Astragalus propinquus),respectively.Groups B3 and B4 were fed with the diet containing 2% and 4% compound preparation B(mainly composed of Eumoia ulmoides,supplemented by Calendula officinalis and Astragalus propinquus),respectively.Groups C5 and C6 were fed with the diet containing 2% and 4% compound preparation C(mainly composed of Astragalus propinquus,supplemented by Calendula officinalis and Eumoia ulmoides),respectively.Control group(D7)was fed with basal diet without compound preparation.Then,growth performance,histological morphology of immune tissues,non-specific immune response and relative percentage survival(RPS)were detected,the results are as follows:1.The effect of compound Chinese herbal medicine on the growth performance in blunt snout bream: there were no fish died in any groups after continuous feeding for 28 days.The weight gain rate(WGR)and specific growth rate(SGR)of fish from groups B4,C5 and C6 increased significantly when compared to control fish(P<0.05),and the WGR was 12.6%,14.2% and 16.6%,respectively.In contrast,the WGR and SGR of fish from groups A1,A2 and B3 did not change significantly(P>0.05).Interestingly,a significant decrease was detected in the feed conversion rate(FCR)of fish from groups B4,C5 and C6 when compared that of control fish(P<0.05).The condition factor of fish was the lowest in group A1 and control group,but the highest in groups C5 and C6,which was significantly higher than that in control group and group A1(P<0.05).Interestingly,there were no significant differences in groups A2,B3 and B4 when compared to other groups.2.The effect of compound Chinese herbal medicine on the morphology of immune tissues in blunt snout bream: at days 14 and 28 during the period of feeding,we measured the morphological changes in different tissues by histological study.The results showed that,in control and compound preparation A groups(A1 and A2),clear pathological changes in liver,spleen,kidney and gut appeared at 14 days first,and the lesions aggravated over time.However,the tissues of fish in compound preparation B groups(B3 and B4)and compound preparation C groups(C5 and C6)remained healthy during the 28-day feeding period.3.The effect of compound Chinese herbal medicine on non ?specific immune response and disease resistance in blunt snout bream: the number and activity of immune cells in blood and the activity of non-specific immune factors(lysozyme LZM,superoxide dismutase SOD,catalase CAT)were assessed at days 7,14,21 and 28 during feeding.The results showed that compound preparation C groups(C5 and C6)performed best,in which group the number of erythrocytes and leukocytes increased significantly at 7 days(P<0.05),and the phagocytic activity of leukocytes and LZM,SOD and CAT activities enhanced significantly at 14 days(P<0.05).Compound preparation B groups performed second,feeding for 14 days at a high dose(4%)could significantly increase the number and phagocytic activity of leukocytes and LZM activity(P<0.05).However,compound preparation A groups(A1 and A2)performed worst,only the number of leukocytes increased during the feeding period(P<0.05).After 28 days feeding study,we developed an infection model that blunt snout bream experimentally exposed to Aeromonas hydrophila,and the results showed that compound preparation C could really improve the resistance of blunt snout bream to Ahimomonas hydrophila.In conclusion,the diet containing 4% Chinese herbal medicine compound preparation C leads to improve the growth performance,histological structure of immune tissues,the disease resistance and non-specific immune response of blunt snout bream. |
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