Screening Of Compound Feeding Attractant And Its Effect On Growth,Immunity And Intestinal Tissue Morphology Of Yellow River Carp

Yellow River carp is a unique aquaculture species in Shandong province,and because the current development status of feed resource shortage inhibits the development of aquaculture industry,the research and development of attractants is extremely important for the sustainable development of aquaculture industry.In order to study the attractants effect and application effect of non-amino acid predators on Yellow River carp,firstly,the best attractants concentration of single predator,the best compound predator ratio,and the application effect of compound predator addition on Yellow River carp were systematically studied and screened by repeated tests,comparative tests and difference analysis using the labyrinth predator test method,and the results of the study are as follows:1.Maze test of a single attractant on Yellow River carp: In order to investigate the best concentration of single enticement agents,eight single enticement agents were selected in the experiment,and the best concentration screening was conducted by maze enticement test with the number of fish collected as the index,and the best concentration of each single enticement agent was obtained as follows: DMPT 0.06%,Chenpi powder 0.22%,garlic powder 0.05%,monosodium glutamate 0.07%,yeast powder 0.75%,glucose 0.09%,TMAO 0.62%,and betaine 0.36%.2.Maze test of compound attractants on Yellow River carp: This is because the effect of single enticement agent is not as good as the compound enticement agent enticement effect.In order to investigate the comparison of the luring effect of different compound luring agents on Yellow River carp,the first six luring agents with better luring effect were selected in the experiment and combined into twenty compound luring agents by choosing three out of six for the maze luring test,and the best compound luring agent was screened by the number of fish collected,and the results were obtained as 0.06% DMPT + 0.22% Chenopodium powder + 0.75%yeast powder,0.05% garlic powder + 0.06% DMPT + 0.75% yeast powder and 0.07%monosodium glutamate + 0.22% stale peel powder + 0.36% betaine,three kinds of compound predators with better attractants effect were obtained.3.Effectiveness of compound food attractants on Yellow River carp:The growth test was set up as five treatment groups,with group I being the fishmeal group(positive control)and group II being the no-fishmeal group(negative control),with compound food attractants 1(0.06%DMPT + 0.22% Chenopodium + 0.75% yeast powder),compound food attractants 2(0.05%garlic powder + 0.06% DMPT + 0.75% yeast powder),and compound food attractants 3(0.07%monosodium glutamate + 0.22% Chenopodium + 0.34% betaine)added on top of the base diet for group II,respectively.0.07% monosodium glutamate + 0.22% stale peel powder + 0.34%betaine)for groups III,IV and V,respectively.(1)Growth and blood indices: weight gain rate,final average weight and specific growth rate in groups III,IV and V were significantly higher than those in the negative control group(P<0.05),while feed coefficients in these three groups were significantly lower than those in the negative control group(P<0.05);hepatopancreas ratio in groups III,IV and V was significantly lower than that in the negative control group(P<0.05),and fatness in group III was significantly higher than that in the negative control group(P<0.05).Among the fish composition indexes,the crude protein content of groups III,IV and V was significantly higher than that of the negative control group(P<0.05).The results of blood indexes showed that the differences of blood glucose,globulin,total cholesterol,AST and ALT in the serum of each experimental group were not significant(P(29)0.05).However,the albumin content of the negative control was significantly higher than that of the other 4 groups(P<0.05),the total triglyceride content of group I was significantly higher than that of the other 4 groups(P<0.05),and the lowest value of total triglyceride content was reflected in the negative control group.(2)Immunological and antioxidant indexes: among the immunological indexes,serum and parotid lysozyme levels were significantly higher in groups III,IV and V than in the negative control group,with the highest in gill group III,16.6% higher than in the negative control group(P<0.05);liver lysozyme levels were significantly higher in groups III,IV and V than in the negative control(P<0.05),with group III was 10.1% higher than that of the negative control group.Acid phosphatase in serum was significantly higher in groups I and III than in the negative control group(P<0.05),with group III being 12.1% higher than the negative control group.Among the antioxidant indexes,the SOD,CAT content and total antioxidant capacity of serum,liver and gills in groups III,IV and V were significantly higher than those in the negative control group(P<0.05),with serum SOD and total antioxidant capacity in group III being 19.7% and 15.9% higher than those in the negative control group,respectively,and liver GSH content in groups III,IV and V being significantly higher than those in the(P<0.05),and the MDA contents in serum,liver and gills were lower than those in the negative control group.(3)Intestinal histomorphology: the fold height in the foregut was significantly higher in groups III,IV and V than in the negative control group(P<0.05),and the fold width in group III was significantly higher than in the negative control group(P<0.05);there was no significant difference between the thickness of the muscular layer in the foregut(P>0.05).In summary,the addition of food attractants to the diet significantly increased the weight gain rate,feed utilization efficiency and specific growth rate of Yellow River carp;the addition of food attractants significantly increased the content of lysozyme and SOD in serum,liver and gill,increased the content of acid phosphatase and CAT in serum,enhanced the total antioxidant capacity of fish,reduced the content of MDA in serum,liver and gill,and enhanced the immune capacity of yellow river The height and width of the intestinal folds of the test group with the addition of food attractant in the diet increased significantly,indicating that the compound food attractant also promoted the digestion and absorption of the intestine,and had a certain role in reducing intestinal damage.Among the three experimental groups with compound food attractants,group III(0.06% DMPT + 0.22% Chenopodium + 0.75% yeast powder)performed better in all indices and was more suitable to be added to the diet of Yellow River carp.