| In order to industrialize animal dung from large cattle farm, we explored the feasibilityof cattle dung conversion using Tenebrio molitor. Cattle dung was mixed with normal feeds(65%wheat bran,30%corn flour,5%bean pulp) and fermented by the effectivemicroorganisms (EM). Cattle dung of60%(FD1) and80%(FD2) were respectively pickedout as treatments to feed the larvae. The effects of different fermented feeds on the growth,death rate, pupation rate and the antioxidant system etc. of Tenebrio molitor were carefullycompared. Our findings demonstrated that FD1treatment would help to market the utilizationof cattle dung with the three aged Tenebrio molitor. The results are as follows.Physicochemical properties of fermented feedstuffs showed significant changes duringthe fermentation. The contents of acid detergent fiber of fermented feedstuffs, which hadrespectively80%、60%、40%、20%of cattle dung, dropt respectively by13%、17%、19%、26%(P<0.05), and the contents of neutral detergent fiber by21%、27%、31%、35%(P<0.05)respectively by the end of fermentation, when the contents of crude protein improvedrespectively by8.6%、8.7%、4.3%、2.8%(P<0.05), revealing the improvement of feedstuffnutritive value. The treatment of group60%reached a beater ferment effect than group80%with pH5.0, mellow smell, and softness character, which was illustrated by the scores offermented feedstuffs quality evaluated by sensory indexes.It was the favorable adaptability of treatment FD1that benefited the domestication ofTenebrio molitor which had more fats and higher conversion ratio. In FD1, the fermentedfeedstuff also improved the single larva’s digestibility, average body mass, crude fat contentand by7%,28%,17%respectively against CK, and the average food intake of single bodyreach to15g. The ones having more eggs and higher evenness degree of pupation should bepicked out as the provenance of next generation, because the amount of FD1and FD2singlefemale oviposition in the polygamous mode decreased by1.2%and33%respectively, and the evenness degree of pupation decreased by28%and42%respectively. The fermentation hadlittle effects on the hatching rate, emergency rate and female to male radio, which willcontribute to the domestication of Tenebrio molitor.The fermented feedstuffs had some particular effects on Tenebrio molitor seeming asenvironmental stress. For instance, the larvae in FD1、FD2suffered some peroxidationdamage at different degrees, for example,60days later after treatment, the content of MDAraised by54%and113%respectively. Autioxidant enzyme activities could be improved so asto reduce the damage of reactive oxygen species, and45days later after treatment the activityof SOD in FD1and FD2elevated by47%and52%respectively. During the whole treatmentperiod, the activity of POD was almost higher than that of CK, especially on the60th day, theactivity of POD increased by52%and83%respectively against CK. However when thepercentage of cattle dung came to80%in feedstuff, the fermentation decreased the activity ofautioxidant enzyme, for example, the activities of SOD and CAT decreased by35%and44%respectively on the60th day after treatment.72hours later after the15minutes freezetreaments, the death rate of Tenebrio molitor larvae decreased by18%respectively againstCK, showing superior ability of cold resistance. During the whole growth and developmentperiod, FD1and FD2had higher death rate than CK, especially in the25~70days reaching24%and46%respectively, although the death rate of FD1was decreasing generation bygeneration.Eight kinds of bacterium such as Exiguobacterium, Cellulomonas, Acetobacter, Bacillussubtilis, Staphylococcus, Proteus, Citrobacter, Listeria were isolated from the intestinal canalof FD1, and most of them were fond in CK having no significant distinction in quantityexcept Exiguobacterium Cellulomonas and Bacillus subtilis, which could decomposecellulose or restrain the growth of pathogenic bacterias. This would be helpful to thedevelopment of probiotics for Tenebrio molitor. |
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