The Hygiene Research On Piggery Bio-Fermentation Litter

Deep litter system is a farming techniques based on reducing the animal wastes pollution and improving the barns environment. In order to study the fermentation litter hygiene status, assess the enrichment of heavy metal in the litter and the impact on plant growth and plant residues. In this study, by selecting three deep litter system farms, collected bio-fermentation litter by different time of using, different depths and at different barns feeding different stages of pigs. Determination variation of moisture, total N, total P, soluble salts, aflatoxin B1(AFB1), the number of E.coli and B. subtilis, heavy metals (all heavy metals and effective heavy metal) to assess their litter hygiene status. Pot cultivation test, litter and soil mixed in different proportions, and study the impact of mixed soil on plant growth and residues of heavy metals (Cu, Zn) from the litter to the plants.1. The component of litter: with prolonged time of use, the moisture content reduced gradually. In different depths (from the ground25cm,60cm,85cm), the moisture content from top to bottom shown a gradually downward trend. As the depth increases, the litter temperature gradually increased. As the depth increases, the litter temperature increased, the number of E. coli and B. subtilis shown a decreasing trend. With prolonged time of use, the number of the B. subtilis also shown a downward trend.With prolonged time of use, Total N decreased while the total P increased, But both did not shown significantly change. Soluble salt content in the litter shown a significantly increase (P<0.05).In this research, the AFB1was detected in the litter of different ages. The content were less than10ppb. Although less, the pigs grown on the litter long time and had nature instincts of digging litter, there is still potential hazard for pigs.The ammonia concentration in the fermentation bed piggery(5.36mg/m3) was significantly lower than the content of concrete floor the piggery (9.03mg/m3)(P<0.05), the fermentation bed played a significant role in improving the barns air.The content range of Cu, Zn,Pb in litter is153.91-409.15mg/kg,248.69-622.09mg/kg,1.39-2.78mg/kg. With prolonged time of use, the enrichment of Cu, Zn and Pb shown significantly increased (P<0.05). From view of depths, the middle layer was significantly higher than the bottom(P<0.05), but the difference between bottom and upper, middle and upper was not significant. In addition, the effective heavy metal was also a important evaluating indicator of heavy metal pollution. By measuring, with the extension of the using life, the effective heavy metal also shown significantly increase (P<0.05).In different barns feeding different stages of pigs, the content Cu, Zn in piglet house was higher than the hog finishing house and sow house.2. Pot-planting test:Mixed litter by0%(control group),10%,15%,20%,25%,30%and35%volume fraction with soil and had cultivated test. From the experimental results can be seen that except35%test group, dry weight of the other five treatment groups’ plant were significantly higher than control group(P<0.05), The plants’dry weight of35%treatment group is lower than the other treatment groups.Residues in plants:The residual of Cu in25%and35%treatment group were significantly higher than0%,10%,15%and20%group(P<0.05).30%treatment group was significantly higher than0%and10%test group (P<0.05), but with15%and20%, difference was not significant(P>0.05);15%group and20%group was significantly higher than0%control group and10%treatment group (P<0.05), but the two group are not significant. Residual of Zn in the plant also showed an increasing trend with increase of the ratios of litter. The treatment group was significantly higher than that of the control group (P<0.05);25%,30%and35%group was significantly higher than other treatment groups (P<0.05);20%group was significantly higher than the10%group(P<0.05), but was not significant different with15%treatment group.After planting, the content of effective Cu, Zn was slightly higher than before planting.Conclusions:With the depth increasing, the moisture of litter was decreased, the temperature was increased, the number of E.coli and Bacillus subtilis decreased. With prolonged time of use, the content of Cu、Zn、Pb and soluble salt content shown significant increase. Soil mix with the litter, the content of Cu、Zn increased with adding ratios increasing. After planting, the residues of Cu、Zn in plant increased too. Therefore, when dealing with waste litter, it’s important to measure the impact of litter on the environment and food safety.