| The large-scale development of Apostichopus japonicus cage culture mode in Fujian area and floating cage culture mode in the North has brought great challenges to the feed industry.In the indoor artificial seedling raising and pond breeding mode,the sea cucumber feed is mostly powdery or granular,and the requirements for the dissolution and dispersion performance of the feed are low.However,in the open water breeding mode,a large proportion of the feed will be dissolved and lost outside the cage or cage after feeding,resulting in a significant reduction in the utilization rate of sea cucumber feed,which not only increases the breeding cost,but also pollutes the seawater environment.In this study,the effects of five adhesives on the dissolution performance of A.japonicus feed were evaluated through in vitro experiments.On this basis,the effects of adding four adhesives to the feed on the survival,growth,digestive enzyme and immune enzyme activities and body composition of A.japonicus under cage culture and hanging cage culture were discussed through feeding and growth experiments.The research results will provide a theoretical basis for the development of special compound feed for A.japonicus under the two culture modes.(1)Effects of different kinds of binders on the dissolution of feeds for Apostichopus japonicus: In the experiment of determining the dissolution rate of viscous bait,the sodium alginate group and eel feed group completed the dissolution in 30 hours and 51 hours respectively.The diets of Guyuan powder group,pregelatinized starch group and guar gum group had residual diets after the end of the experiment(72 hours).The dissolution ratio of these three groups was Guyuan powder group > pregelatinized starch group > guar gum group from high to low.In terms of dissolution rate,among the experimental groups added with adhesive,the dissolution rate of Guyuan powder and pre gelatinized starch group was significantly lower than that of other experimental groups(P < 0.05),followed by guar gum and eel material,and the dissolution rate of sodium alginate was significantly higher than that of other groups(P <0.05).The results showed that adding a certain amount of adhesive was helpful to improve the efficiency.According to the experimental results,four kinds of adhesives were used in the follow-up breeding experiment,including glue,pre gelatinized starch,Guyuan powder and eel feed.(2)Effects of supplementation of different binders to feeds on the growth,nutrient composition of body wall,as well as activities of digestive enzymes and immune enzymes of Apostichopus japonicus under net cage culture mode: In the cage culture mode,adding a certain amount of adhesive to the bait can effectively improve the growth performance of cage seedlings.It can be seen from the data that at the end of the experiment,the mortality of the control group(bait without adhesive)reached 66.54%,which was significantly higher(P < 0.05)than that of the other adhesive experimental groups,and its growth rate was the lowest,only 14.97%,which was significantly lower than that of the other adhesive experimental groups(P < 0.05).Four kinds of adhesives were used in this experiment: Eel feed,pre gelatinized starch,guar horn and Guyuan powder.By analyzing the growth indexes of sea cucumber fed with different sticky diets in the cage culture mode,it can be found that there is no significant difference in the survival rate of sea cucumber fed with four types of adhesives,but the weight gain rate of eel feed 106.97% is significantly lower than(P < 0.05)its pre gelatinized starch 197.17%,guar Cape 184.53% and Gu Yuan powder 173.7%.In terms of digestive tract trait index,although the intestinal length and width of young ginseng in the pre gelatinized starch and eel feed group were significantly higher than those in other groups(P < 0.05).In terms of body wall nutrients,the content of body wall crude protein in guar gum group was 4.44% significantly higher than that in other groups(P< 0.05),followed by eel feed 4.29% and Guyuan powder group 4.28%.In terms of total carbohydrate,eel feed 12.59 mg / kg group was higher than other groups,but it was not significant(P > 0.05).In terms of immune enzyme activity,there were significant differences among the experimental groups only in polyphenol oxidase(PPO),superoxide dismutase(SOD)and lysozyme(LZM)(P < 0.05),and there were no significant differences among other types of immune enzyme activities(P > 0.05).In terms of digestive enzyme activity,the trypsin activity of pre gelatinized starch 1599.52 U / mgprot group was significantly higher than(P < 0.05)eel feed group and guar gum group;In terms of lipase activity,6.08 U / mgprot in the control group was higher than that in other viscous material groups,and there was a significant difference with2.95 U / mgprot in guar gum group(P < 0.05).(3)Effects of supplementation of different binders to feeds on the growth,nutrient composition of body wall,as well as activities of digestive enzymes and immune enzymes of Apostichopus japonicus under cage basket culture mode: It can be found that under the mode of cage culture,adding a certain amount of adhesive to the bait can significantly improve the growth performance of cage seedlings.It can be seen from the data that at the end of the experiment,the weight gain rate of young ginseng in each adhesive group was significantly higher than(P < 0.05)the control group by 23.31%.The weight gain of each experimental group from high to low was Guyuan powder group,guar gum group,eel feed group and pregelatinized starch group.In terms of intestinal weight,intestinal wall ratio and intestinal body ratio,Guyuan powder group and eel feed group were significantly higher than other groups(P < 0.05).In immune enzyme activity.The activity of polyphenol oxidase(PPO)in eel feed group and pre gelatinized starch group was significantly higher than that in other groups(P < 0.05);In terms of superoxide dismutase(SOD),there were significant differences between eel feed and guar gum and other groups(P < 0.05),among which guar horn had the highest SOD activity;Nitric oxide synthase(t-nos)in the pregelatinized starch group was significantly lower than that in other groups(P < 0.05);Alkaline phosphatase(AKP)in pre gelatinized starch group was significantly lower than that in other groups(P < 0.05);The lysozyme(LZM)activity in the control group was higher than that in the other groups,and there was a significant difference between the control group and the eel feed group;Secondly,the acid phosphatase(ACP)activity of guar horn group was the highest,but there was only significant difference between guar horn group and gluten group(P < 0.05).In terms of digestive enzymes,there were also significant differences among the experimental groups.The trypsin activity of the control group was generally lower than that of other groups,but there was only significant difference between the control group and the pre gelatinized starch group(P < 0.05);The activity of lipase in the control group was higher than that in other groups;In terms of amylase activity,the pre gelatinized starch group was significantly higher than other groups(P < 0.05),and there was no significant difference among other groups(P > 0.05). |
