| With the rapid development of aquaculture in China,a large number of drug abuse and wastewater discharge caused serious environmental pollution.In recent years,with the improvement of the country’s environmental protection requirements,Chinese herbal medicine has been widely concerned with the characteristics of less toxic and side effects,low residue,and no drug resistance.As natural compounds,some medicinal plants have the potential to replace antibiotics and immunoprophylaxis in aquaculture.This study hybrid grouper(Epinephelus fuscoguttatus ♀ x Elancedatiis came)as test object,studies the two kinds of Chinese herbal,Verbena(Verbena officinalis)and Pyrola(Pyrola calliantha)and 1:1 compatibility herbs for hybrid grouper growth performance,antioxidant capacity,digestive enzymes,the influence of the intestinal structure and immune ability.The experiment was designed as A control group(no Chinese herbal medicine was added)and 9 experimental groups(2%,4% and 6% verbena A,elk B and 2%,4% and 6%1:1 compound AB).Chinese herbal powder was added to the basic feed at different levels and compatibility,and hybrid grouper were fed for 8 weeks.The test results are as follows:1.HPLC method was used to determine: the water extract of verbena contained0.13mg/ml verbenin and the components of halberd verbenin;Arbutin was found in0.13mg/ml of water extract of herba eleutheriae.2.Verbena can be added to the feed to improve the growth performance of hybrid grouper,among which the best effect is 4%.The relative weight gain rate of tiger dragon spot in verbena group(2%,4%,6%)was significantly higher than that in control group(19.42%,47.36%,23.83%,respectively)(p<0.05).The feed coefficient of verbena group(2%,4%,6%)was significantly lower than that of the control group(15.42%,33.71%,20.57%,respectively)(p<0.05).3.The growth of hybrid grouper was inhibited to some extent by the addition of Pyrola into the feed,among which the inhibition effect was the most obvious at the level of 6%.The relative weight gain rate of tiger spot was significantly lower than that of control group(9.5%,7.89%,11.18%)(p<0.05).The feed coefficient of the herba monascus group(2%,4%,6%)was significantly higher than that of the control group(14.85%,19.42%,24%,respectively)(p<0.05).4.The 1:1 combination of verbena and Pyrola in the feed promoted the growth of hybrid grouper to some extent,but the effect was not as obvious as that of verbena group.The relative weight gain rates of group AB4 and group AB6 were significantly higher than those of the control group(15.7% and 13.8%,respectively,p < 0.05),and the feed coefficients were 8% and 5.71% lower than those of the control group(p > 0.05).There was no significant effect of verbena and herba eleutheriae compound on the body shape index of fish and the routine nutritional composition of whole fish(p>0.05).Serum metabolism indexes were not significantly changed(p>0.05).5.The addition of verbena and Pyrola into the feed as well as compound herbs can improve the antioxidant capacity of serum and hepatopanax in hybrid grouper,and eleuthera has the most obvious effect,followed by compound herbs.T-AOC in serum of B6 group was significantly increased by 75.67% compared with control group(p<0.05).The serum CAT activity of B2,B4 and AB2 group was 49.88%,46.30% and 46.77% higher than that of the control group(p<0.05).Compared with the control group,the activity of SOD in liver and pancreas in A2,A4,B2,B4 and AB2 groups were significantly increased by 51.81%,55.53%,59.99%,56.13% and 74.66%,respectively(p<0.05).The t-aoc activity of liver and pancreas in A2,A4,A6,B2,B6 and AB2 groups was significantly increased by 122.72%,140.90%,113.63%,104.54%,131.81%,118.18%(p<0.05),and reached the highest level in A4 group.6.The addition of verbena and Pyrola into the feed can enhance the protease and lipase activity in liver,pancreas and intestinal tract of hybrid grouper,but has no significant effect on amylase.The trypsin levels in A2,A4,B2 and B4 groups were 55.65%,55.62%,59.6% and 55.62% higher than those in the control group(p < 0.05).The lipase levels in A4,A6,B2 and B4 groups were 38.46%,53.84%,35.89% and 38.46% higher than those in the control group(p < 0.05).7.The addition of verbena to the feed can affect the intestinal development of hybrid grouper to a certain extent,and increase the thickness of the intestinal muscle layer and the height of the villi,among which the addition level of 4% has the most significant effect(p <0.05).Deer rana test group can reduce the intestinal muscle layer thickness and villi height of hybrid grouper to a certain extent,but there is no significant change compared with the control group(p > 0.05),AB group has no significant effect(p > 0.05).8.The addition of verbena and stag grass in the feed can improve the expression of immune-related genes Ig M,TRIF and HSP90 in the brain,spleen,kidney and gill of hybrid grouper.A4 and A6 groups significantly increased the expression of HSP90 in the brain,spleen,kidney and gill(p < 0.05),and significantly increased the expression of Ig M and TRIF genes in the gill and kidney(p < 0.05).The expression of three immune-related genes in fish tissues was significantly increased in both groups(p < 0.05).The expression of HSP90,Ig M and TIRF in gill,spleen and kidney was significantly increased in the compound group(p< 0.05).9.Verbena and Pyrola were added to the feed to enhance the immune protection of hybrid grouper.After the challenge test with vibrio alginolysis,the mortality of each experimental group was lower than that of the control group.The lowest mortality rate was12.5% in the herba monascus group,followed by the compound group.To sum up,the results of this experiment showed that the addition of verbena into the feed could significantly improve the growth performance of hybrid grouper,effectively improve the antioxidant capacity and digestive enzyme activity of hybrid grouper,improve the intestinal structure,and improve the expression of immune-related genes.The growth of tiger spots was inhibited to some extent by the addition of herba pyrophylla to the feed,but the antioxidant capacity and immune-related gene expression of hybrid grouper were significantly improved,and the immune protection was improved.Compound herbal medicine added to the feed can promote the growth of hybrid grouper,effectively improve the antioxidant capacity of tiger spots and the expression of immune-related genes,improve the immune protection.The best addition level was 4% verbena in grouper feed. |
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