Enrichment Effect Of Earthworms On Heavy Metals In Pig Manure And Study Of Promoting Growth Of Animals And Security

To relieve the pollution caused by pig manure discharged from large-scale pig farms, earthworms were cultured by using pig manure. This done, on the one hand, the innocent treatment of pig manure was realized; on the other hand, pig manure was used with high effectively, for earthworms was also used as the source of animal protein feed, and so the circulating utilization model of “pig-pig manure-earthworm powder-livestock and poultry” was established.This paper mainly studied the treatment of pig manure by culturing earthworms, and the earthworms' accumulation of such heavy metals as Cu, Zn, Pb, Cr, Cd and As. Trace elements such as calcium superphosphate, potassium sulfate and potassium chloride were added into pig manure disposals, and then their effects on survival rates and cocoon production quantities of earthworms were explored. Ratios of 1 %(Group II), 3 %(Group III) and 5 %(Group IV) of earthworm powder were added into the daily feed for Ningdu Yellow Chicken. Thus the effects of earthworms on the production performance and biochemical indexes of Ningdu yellow chicken as well as on the heavy metals in the chicken bodies were studies. Control Group were fed the basal diet of corn-soybean meal, kept the same crude protein in each group Results showed as follows:1 Effects of earthworms' accumulation of heavy metals from pig manure and its soil improvementAfter the treatment by means of earthworms, the organic content in the worm-cast decreased by 30.9 %, while total nitrogen(TN), total phosphorus(TP) and total potassium(TK) increased by 18.68 %, 35.93 % and 22.5 %, respectively. Earthworms also had certain accumulation effects on Cu, Zn, Pb, Cr, Cd, and As, enrichment factor were 0.35,0.27,0.11,0.84,13.07 and 13.56, following the order as As>Cd>Cr>Cu>Zn>Pb.2 Effects of Trace element addition on earthworms' survival rates and cocoon production quantitiesWhen the proper addition amount of calcium superphosphate, potassium sulfate and potassium chloride reached 0.75, 0.75 and 0.05 mg/kg, respectively. The earthworms' survival rates and cocoon production quantities also reached the highest.3 Effects of earthworm powder addition into daily feed on the production performance and economic benefits of Ningdu yellow chickenCompared with Group I, the daily gain of Group III and IV increased by 9.42% and 19.98%, respectively. While that of Group II decreased by 7.33%. The feed to gain ratio of Group III and Group IV enhanced 12.64 % and 22.45 %, while Group II decreased by 6.04 %. The economic benefits of Group III and IV increased by 17.39% and 34.78 %, respectively when compared with the control, while that of Group IV was the best.4 Effects of earthworm powder addition into daily feed on the blood indicators of Ningdu yellow chickenWith the progress of the tests, the contents of TP, ALB and GLB all increased(P>0.05). Activities of both GOT and GPT decreased, but that of Group IV decreased by 19.43 % and 22.00 %(P>0.05), respectively; the contents of BUN all increased, but that of Group IV only increased by 3.15 %; the SOD contents of Group I, II and IV increased by 21.57 %, 8.24 % and 41.19 %, respectively, while that of Group III decreased by 7.74 %; Significant difference of serum SOD was found between Group IV and I, II, III(P<0.05); the contents of CHE all showed decrease tendency, that of four groups decreased by 15.15 %?16.33 %?11.33 % and 3.86 %, respectively; with the progress of the test, the contents of AKP of four groups showed increase tendency, that of them increased by 5.74 %?1.09 %?20.68 % and 4.01 %, respectively; at the end of the test, when compared with the control, the GSH-PX contents of Group II, III and IV increased by 6.59 %(P>0.05)?8.69 %(P>0.05) and 15.37 %(P<0.05); at the end of the test, compared with that of Group I, the CAT contents of Group II, III and IV increased by 3.52 %(P>0.05)?10.25 %(P>0.05) and 18.64 %(P<0.05).5 Effects of earthworm powder addition into daily feed on the contents of heavy metals in Ningdu yellow chicken bodiesThe contents of heavy metal in liver and muscle of group I, group II, group III and group IV were all in line with national standards: the limit of pollutants in food(GB2762-2012).These results suggest that the content of TN, TP and TK were improved., but generally the organic matter was decreased; the accumulation of heavy metals in pig manure by earthworms was showed to some extent, and the order of the accumulation followed as As>Cd>Cr>Cu>Zn>Pb. A certain amount of trace elements in earthworms' daily feed could improve the survival rates and cocoon production quantity. The use of 5 % of earthworm powder to partially replace soybean meals significantly improved the production performance and economic benefits of Ningdu yellow chickens, and strengthened their immunity and oxidation resistance. The contents of heavy metals in muscles and livers of Ningdu yellow chicken were all in line with the national standard.