| Recent years, with the increasing demand for the aquatic products,the aquacature has got rapid development,the scale,intensive is growing more and more,but the same time,the water environment is deteriorating,and the fish disease is outbreaking continually,that bring huge economic losses for the aquaculture industry.As the widespread use of the antibiotics and many kinds of chemical drugs,has achieved obvious effect,but for long time and large numbers use of them,have led to the bacteria resistance increasing and lots of drug residuse,this made great hazard on human health.Because of its nature ingredients of Chinese herbal medicine,lower toxicity,lower prices,and with no resistance,that it has been widely used in the aquaculture industry.Many studies show that the Radix Isatidis has obvious effects in anti-microbial and anti-virus,and reports have shown that Radix Isatidis has good effects in disease prevention.This study uses carp as the research of object,respectively to add 1.00%,2.00%,4.00% extractive of Radix Isatidis by water and by alcohol into the basi c feed of carp.In 14 th day,28 th day,42 th day, collected the intestinal contents a nd intestinal tissue,to study the effects of digestive function for carp by differe nt extraction methods and different concentrations of Radix Isatidis.The results show:in 14 th,the activity of Trypisn in experimental group is lower than the control group,prolonged with feeds,the activity of Trypisn in each experimental group increase gradually,there is no significantly difference with the control group(P>0.05).With the increasing of the addition of Radix Isatidis,the activity of Lipase is on a declining curve. The activity of Lipase in group of extractiv e by alcohol is always lower than the control group, and the group of extracti ve by water is higher than the control group, the difference is significant(P<0.05).The activity of Amylas in the experimental group is higher than the controlgroup, and the difference is significant. In the 14 th,the hight of the foregut a nd hingut in experimental group is higher than the control group, and the diffe rence is significant(P<0.05).The value of V/N of foregut in the 14 th day in e xperimental group is lower than the control group, no significant difference. Pr olonged with feeds, the value of V/N is up to the rise. With the increasing ofconcentration, the value of V/N in hindgut is on a declining curve, the extrac tive by alcohol is lower than by water, no significant difference.Collecting the blood samples of carp in the 14 th, 28 th, 42 th day, used in the detection of the immune indexes. The result show that: the activity of AKP, SOD, LSZ in the experimental group is higher than the control group, and the high concentration is better than the low concentration. The content of TP is downtrend with the concentration increasing, but only group E3 is lower than the control group. The content of GLB is higher than the control group in the 42 th day, significantly different(P<0.01).The content of ALB in experimental group is lower than the control group, as a whole with the increasing of concentration is on the decline.The result of challenge assay show: the immune function of the experimental group is significantly higher than the control group, the Radix Isatidis has controled the mortality rate of carp. |
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