Study On Ecological Diets Being Beneficial To Pig Manure Biogas Fermentation

The experiments were conducted to investigate ecological diets which werebeneficial to pig manure biogas fermentation. Pig performance, feed conversion rateand other indicators of fecal residues were measured by feeding trials. The pig manurebiogas fermentation was conducted to investigate the effects of ecological diets on pigmanure biogas. Piglets and growing pigs were selected as experimental animals. Sixtyweanling piglets (Duroc×Landrace×Large,10.15±1.10kg,28d of age) and sixtygrowing piglets (Duroc×Landrace×Large,22.00±1.50kg,60d of age) were randomlyallotted to one of five dietary treatments with3replicates per treatment and4pigletsper replicate respectively. The pigs of control group were fed normal diets of farm(NY/T65-2004). The dietary protein content of test I group was lower2%than that ofthe control group, amino acid levels were adjusted according to the NRC (2012)standards, and the amount of calcium hydrogen phosphate was reduced after addingphytase. Other nutritional levels were the same as control group. Diets of test II groupwere that antibiotics and arsenic formulation in test I group were replaced byprobiotics and compound enzymes. The inorganic trace elements in test group II werereplaced by organic trace elements in diets of test III group. Dased on diets of test IIIgroup, mannan oligosaccharides and cysteamine were added in diets of test IV group.The results showed that average daily gain (ADG) of control group, test I, II andIII group had no significant difference (p>0.05), and the ADG of test IV group wassignificantly improved (p<0.05) in weaned piglets and growing pigs feeding trials.In feeding trials of weaned piglets and growing pigs, average daily feed intake(ADFI) of the test group and the control group did not differ significantly (p>0.05). Inthe feed conversion rate, compared with control group, test I group, II group and IIIgroup had no significant difference (p>0.05). Compared with the control group, Feedconversion rate of the experimental group IV significantly increased (p<0.05). Therewere no significant difference (p>0.05) in feed conversion rate between experimentalgroup I, II and III (p>0.05).In weaned piglets and growing pigs feeding trials, due to the adding phytase andthe reduction of dietary protein and phosphorus content, pig fecal nitrogen andphosphorus content of test I, II, III, IV group was significantly reduced compared with the control group (p<0.05). The copper and zinc content of pig feces in experimentalgroup I and test II group did not change significantly (p>0.05). After the use oforganic trace elements, The copper, zinc content of pig feces in test III and IV wassignificantly lower than that of the control group (p<0.05).Laboratory biogas fermentation experiments were conducted with pig manure.The results showed that the time to start gas production and to end gas production oftest groups were earlier than that of the control group to different degrees. Time of gasproduction peak in each experimental group was earlier than that of the control groupto different degrees. The experimental IV group appeared gas production peak at6days after the experiment, the time was shortest.In summary, protein content of diets was reduced by2%, amino acid levels wereadjusted according to the NRC (2012) standards, and the amount of calcium hydrogenphosphate was reduced after adding phytase. Probiotics and compound enzymepreparation were used to replace antibiotics and arsenic in ration formulation. Therewere no significant effects on growth performance of weaned pigs and growing pigs.Based on the above, inorganic trace elements of diets were replaced with organic traceelements. The content of nitrogen, phosphorus and other trace elements such ascopper and zinc content of pig feces decreased significantly. Especially the additionof mannan oligosaccharide and cysteamine increased significantly productionperformance and feed conversion rate of weaned piglets and growing pigs. Throughthe above comprehensive measures, the time of gas production and gas productionrate in biogas fermentation could be obviously promoted. Farms could deal with thefeces by anaerobic fermentation more effectively.