| Tenebrio molitor breeding industry will produce a large amount of insect feces,which is a waste of resources if not handled properly.How to make full use of Tenebrio molitor feces is a realistic problem faced by Tenebrio molitor breeding industry at present.In this paper,Tenebrio molitor feces was taken as the research object,and its adsorption performance was studied on the basis of testing its nutritional components and heavy metal content.On this basis,the feces was further fermented to prepare functional feed for shrimp Calcium supplementation.The main research contents are as follows:1)Nalysis of main nutrient components,basic properties and heavy metal content;2)Adsorption of Ca2+in simulated aquaculture water by insect manure,study its influencing factors,adsorption thermodynamics and kinetics,and investigate the existing forms of Calcium on insect manure before and after adsorption;3)To explore the feasibility of using insect manure as raw material to prepare Calcium-absorbing feed for aquatic organisms;Study the influencing factors,adsorption thermodynamics and kinetics of insect manure feed adsorption;4)carrying out anaerobic fermentation treatment on insect manure and measuring soluble Calcium content;5)Compare the nutrient content of fermented feed,unfermented feed and commercial feed;6)Compare the feeding effects of fermented feed,unfermented feed and commercial feed prawn.Analysis results:1)The content of crude protein in insect manure is 23%,the contents of trace elements such as zinc,magnesium,Calcium and copper are abundant,and the contents of heavy metals such as Cd,Cr,Pd and Hg meet the hygienic standards of feed raw materials,so it is feasible to use insect manure as feed raw materials.2)The best adsorption conditions for Ca2+by insect manure are as follows:temperature 20℃,adsorption time 1h,initial concentration 100mg/L,p H 7,maximum adsorption capacity 9mg/g.The adsorption process accords with pseudo-second-order kinetic equation,and the control of intragranular diffusion is the control step.Isothermal adsorption of Calcium on insect sand accords with Langmuir model,and the adsorption process ofΔG<0 is a spontaneous process.The Calcium adsorbed by insect feces exists in the acid-soluble state and the reducible state which can be biologically utilized,accounting for 78%and 22%respectively.3)The adsorption effect of insect manure to Ca2+has little change after it is made into feed.The best adsorption condition of insect manure feed for Ca2+is close to that of insect manure,and the maximum adsorption capacity is 8 mg/g.The adsorption process accords with pseudo-second-order kinetic equation,isothermal adsorption accords with Langmuir model,andΔG<0 adsorption is a spontaneous process.4)The best proportion of fermented worm manure by lactic acid bacteria is:100parts of fermentation raw materials,5 parts of shell powder,100 parts of deionized water,5 parts of brown sugar and 6 parts of fermentation bacteria.Under this proportion,the content of water-soluble Calcium in the finished feed is 16mg/g.The optimal fermentation temperature is 35℃and the optimal fermentation time is liquid fermentation for 2 days and solid fermentation for 2 days.5)The content of soluble Calcium in unfermented feed and commercial feed is similar to only about 2mg/g,and the content of soluble Calcium in fermented worm manure feed is 16 mg/g..The contents of crude protein,crude fat and acidolysis amino acids in the three feeds are similar.Free amino acid content of commercial feed>fermented feed>unfermented feed,free essential amino acid content of fermented feed and commercial feed is close to and far greater than unfermented feed content.The content of organic acids increased significantly before fermentation.6)The growth rate of Shrimp:fermented feed>unfermented feed>commercial feed;Hulling cycle:fermented feedunfermented feed>commercial feed.The concentration of Calcium ions in the water fed with fermented feed is relatively increased,while that of Calcium and magnesium ions in the water fed with unfermented feed is relatively decreased,and the concentrations of other ions and metal ions are similar.Using insect feces as one of the feed raw materials to prepare shrimp feed can meet the normal growth of shrimp and improve the economic benefits of insect feces to a greater extent.The insect feces has a good adsorption effect on Calcium in water.After being prepared into Shrimp feed,it can promote the absorption of Calcium in water by Shrimp.However,when the concentration of Ca2+in water is low,the adsorption capacity of unfermented wormcast feed is low,which can’t meet the demand of Calcium for shrimp molting.Moreover,the attractivity of unfermented wormcast feed shrimp is also promoted.Therefore,in this paper,lactic acid bacteria fermentation is used to improve the nutritional value,organic Calcium and attractivity of feed.This paper provides a new way for the treatment of a large number of by-products in Tenebrio molitor breeding industry. |
