| The yield of food waste is growing with the development of economy and the improvement of living standards.The large amount of food waste accumulation and improper disposal not only result in waste of resources but also the pollution of water,soil and air,therefore the search a new-type and efficient food waste treatment method is an important issue that must be solved.This research through introduce and domesticate local housefly,using orthogonal experimental design to explore the most optimizing ratio of food waste,breeding density and add substrate method of housefly bioconversion food waste,calculating food waste mass conversion rate and determining physiological and biochemical indicators of housefly larvae to analyze its transformation effect and product quality.In addition,using larvae product breeding tilapia to explore its feasibility and safety for fish farming.（1）Breeding density of 10.0 g/kg,the ratio of food waste（staple food:dishes）is 1:3,one-time fill all substrate is the most optimizing method of housefly bioconversion food waste.The method of food waste mass conversion rate above 75%,larvae production over120 g/kg,larval weight is about 0.51 g（weight of 50 larvae）,larvae protein content above52%and meet the national standard for fish meal in China（GB/T 19164-2003:protein≥50%）.（2）The use of larvae bioconversion food waste,the protein content of larvae product is 52.8±2.12%,exceed the national standard for fish meal in China（GB/T 19164-2003）.The larvae product contains rich amino acids,the E%and E/N is 45.1%and 0.81,which was higher the reference protein mode of FAO-WHO（Food and Agricultural Organization-World Hospital Organization）.The residue moisture（25.4±5.02%）reduce about 59.5%before the bioconversion,organic matter content（59.0±2.18%）more than14.0%of the national organic standard（NY 525-2012）and contained more NPK,can be used as the high quality organic raw materials.（3）In the experiment of tilapia aquaculture with larval products,the tilapia be feed by fresh housefly larvae with the highest survival rate（90.0%）,the tilapia be feed by dry housefly larvae has the highest weight gain rate and fatness is 75.7%and 2.14%respectively.Crude protein and crude fat content of the tilapia be feed by dry housefly is higher than that tilapia of be feed fresh housefly larvae.（4）The meaning contents of different heavy metal of housefly larvae displayed the following trend:Zn>Cu>Cd>Cr>Pb>Ni.And the enrichment factor of Zn,Cu,Pb and Cd were all higher than 1,but the heavy metal contents of housefly larvae were entirely lower than the Chinese National Standards（GB/T19164-2003）.The contents of different heavy metal of food waste residue displayed the following tendency:Zn>Cu>Cr>Ni>Pb>Cd,and the contents of Zn,Cu,Pb and Ni in food waste residue were higher than that were detected from food waste.The4)values of all heavy metal in food waste residue samples were below 40,indicated that there were no heavy metals contamination of food waste residue.The heavy metal contents of tilapia be feed by dry housefly larvae were below commercial dry larvae treatment.And the contents of Cu,Cr,Cd and Ni of tilapia be feed by fresh housefly larvae were lower than other treatments.In addition,the Target Hazard Quotients of all heavy metal about tilapia in all breeding treatments were below 1,indicating that there was no health risk. |
