Effects of Bacillus-based inoculum on odor emissions co-regulation, nutrient element transformations and microbial community tropological structures during chicken manure and sawdust composting.

This study aims to evaluate whether different doses of Bacillus-based inoculum inoculated in chicken manure and sawdust composting will provide distinct effects on the co-regulation of ammonia (NH3) and hydrogen sulfide (H2S), nutrient conversions and microbial topological structures. Results indicate that the Bacillus-based inoculum inhibits NH3 emissions mainly by regulating bacterial communities, while promotes H2S emissions by regulating both bacterial and fungal communities. The inoculum only has a little effect on total organic carbon (TOC) and inhibits total sulfur (TS) and total phosphorus (TP) accumulations. Low dose inoculation inhibits total potassium (TK) accumulation, while high dose inoculation promotes TK accumulation and the opposite is true for total nitrogen (TN). The inoculation slightly affects the bacterial compositions, significantly alters the fungal compositions and increases the microbial cooperation, thus influencing the compost substances transformations. The microbial communities promote ammonium nitrogen (NH4+-N), TN, available phosphorus (AP), total potassium (TK) and TS, but inhibit nitrate nitrogen (NO3--N), TP and TK. Additionally, the bacterial communities promote, while the fungal communities inhibit the nitrite nitrogen (NO2--N) production. The core bacterial and fungal genera regulate NH3 and H2S emissions through the secretions of metabolic enzymes and the promoting or inhibiting effects on NH3 and H2S emissions are always opposite. Hence, Bacillus-based inoculum cannot regulate the NH3 and H2S emissions simultaneously.

Independent and combined effects of antibiotic stress and EM microbial agent on the nitrogen and humus transformation and bacterial community successions during the chicken manure composting.

This study aimed to investigate the independent and combined effects of antibiotic and EM microbial agent on the nitrogen and humus (HS) transformations as well as the bacterial community successions during the chicken manure and rice husk composting. EM microbial agent accelerated the oxytetracycline (OTC) degradation, but slowed down the norfloxacin (NOR) degradation. OTC inhibited the TN retention and promoted the HS accumulation, both NOR and EM microbial agent inhibited the TN retention and HS accumulation, while EM microbial agent showed an antagonistic effect on TN immobilization with antibiotics and reduced the impacts of antibiotics on HS. Obvious bacterial community successions occurred. Firmicutes were related to HS transformation, while Firmicutes, Actinobacteriota and Proteobacteria were associated with nitrogen conversion. NOR promoted the transformations of NH4+-N to NO3--N and FA to HA. The findings provided theoretical data for the recycle of antibiotic-contaminated manure and the efficient production of high-quality compost.

L-Leucine In Ovo Administration Causes Growth Retardation and Modifies Specific Amino Acid Metabolism in Broiler Embryos.

L-Leucine (L-Leu) in ovo administration was demonstrated to afford thermotolerance and modified amino acids metabolism in post-hatched broiler chicks under heat stress. This study aimed to investigate the changes in embryonic growth and amino acid metabolism after in ovo injection of L-Leu. Fertilized broiler eggs were subjected to in ovo injection of sterile water or L-Leu on embryonic day (ED) 7. The weight of embryos and yolk sacs were measured on ED 12, 14, 16, and 18. Plasma and livers were collected on ED 14 and 18 for free amino acid analysis. The weight and relative weight of embryos were significantly lowered by in ovo administration of L-Leu, but those of yolk sacs were not altered. Moreover, L-Leu in ovo injection significantly reduced the plasma proline concentration during embryogenesis and increased the plasma concentrations of tyrosine (Tyr) and lysine (Lys) in ED 18. Hepatic Lys concentration was also significantly increased by L-Leu in ovo injection. Interestingly, Leu concentrations in the plasma and liver were not affected by L-Leu administration. These results indicated that in ovo administered L-Leu was metabolized before ED 14 and affected embryonic growth and amino acid metabolism during embryogenesis.