| As a kind of resource insect,black soldier fly(Hermetia illucens)has been more and more widely used in the utilization of agricultural organic solid waste such as kitchen waste and livestock manure in recent years.The current treatment methods of three kinds of agricultural wastes,namely,foxtail algae(Myriophyllum verticillatum),water hyacinth(Eichhornia crassipes)and rapeseed dregs,all have some drawbacks,which can not be handled properly efficiently and safely,which is easy to cause secondary pollution.This paper attempts to use the black soldier fly for biotransformation,through the determination of the feeding characteristics of larvae,the safety evaluation of larvae and organic manure and the characteristics of intestinal flora,to explore a new mode of resource utilization of agricultural waste based on black soldier fly.The main results are as follows:1.Foxtail algae,water hyacinth and rapeseed dregs can be used as the only source of nutrients for the growth and development of black soldier fly larvae.compared with balanced chicken feed,the growth and development of black soldier fly larvae are significantly different.Among the three groups fed on different agricultural wastes,the average time of emergence of prepupae in C300 group was the shortest,the weight of prepupae was the highest,the average days was 12 days,and the weight of single prepupa was 155.6 mg.The dry matter conversion rates of chicken feed group,foxtail algae group,rapeseed dregs group and water hyacinth group were 30.11% ～ 38.48%,4.85% ～ 11.8%,24.68% ～ 35.62% and 2.4% ～ 6.4%,respectively.the variation range of feed-meat ratio was 0.71 ～ 3.65,7.02 ～ 16.82,0.86 ～ 2.96 and 8.52 ～ 17.12,respectively.The average daily optimal feeding amount of black soldier fly cultured with foxtail algae,rapeseed dregs and water hyacinth was 100 mg ～ 200 mg,50mg ～100mg and 100 mg ～ 200 mg,respectively.2.When the black soldier fly feeds on different foods,there are significant differences in the nutritional composition of its insect body and feces.The contents of crude protein,crude fat,crude fiber and crude ash were 36.9% ～ 42.28%,10.74% ～ 42.23%,6.17% ～ 17.19% and6.93% ～ 29.83%,respectively.The larvae of rapeseed dregs group had the highest crude protein and crude fat content,and the water hyacinth group had the highest crude fiber and crude ash content.The contents of Cr,Cd,As and Cr in larvae of foxtail algae group and water hyacinth group exceeded the feed hygienic standard(GB 13078-2017).The content of organic matter in insect feces is 54.77% ～ 60.11%,and the total nutrient content is 4.05% ～ 12.31%.The total nutrient content of insect feces in fox tail algae group(4.05%)was slightly lower than the standard of organic fertilizer(≥5.0%,NY 525-2021).3.There were significant differences in intestinal microbial composition of black soldier fly fed on different foods.The contents of crude protein(r2 = 0.968),crude fat(r2 = 0.843)and crude fiber(r2 = 0.59)had significant effects on the structure and composition of intestinal microorganisms.In terms of species diversity,water hyacinth group had the highest species diversity and species abundance,and water hyacinth group and fox tail algae group had significant differences compared with the other three groups.In terms of β diversity,the degree of Weighted Uni Frac interpretation was as high as 72.9%,and there were significant differences among groups.The dominant bacteria were Dysgonomonas and Lactobacillus in chicken feed group,Dysgonomonas,Orbaceae,Klebsiella and Defluvimonas in foxtail algae group,Dysgonomonas,Enterococcus,Bacteroides and Bacillus in water hyacinth group,and Enterococcus,Campylobacter and Morganella in rapeseed dregs group.There were significant differences among the groups of species with different abundance.There was no significant difference in intestinal neutral protease activity of black soldier fly.The intestinal lipase activity of water hyacinth group was the highest,and the NP activity was 26.61 U/g,while that of fox tail algae group was the highest,and the NP activity was 7.39 U/g. |
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