Odor emissions represent one of the important issues of aerobic composting. The addition of microbial agents to compost is an important method for solving this problem, but this process is often unstable when a single microbial agent is added to the compost. Therefore, in this study, five treatments comprising different proportions of Bacillus stearothermophilus, Candida utilis, and Bacillus subtilis were tested to determine the best combination of the three microbial agents for ammonia reduction, as follows: control group (CK), 2:1:1 (A), 1:1:2 (B), 1:2:1 (C), and 1:1:1 (D). Compared with the CK group, the A, B, C, and D groups reduced ammonia emissions by 17.02, 9.68, 53.11, and 46.23%, respectively. The total ammonia emissions were significantly lower in C and D than in CK (p < 0.05). These two treatment groups had significantly increased nitrate nitrogen concentrations and decreased pH values and ammonium nitrogen concentrations (p < 0.05). Throughout the composting process, the total bacterial number was significantly higher in C and D than in CK (p < 0.05). Therefore, it is likely that B. stearothermophilus, C. utilis, and B. subtilis compounded from 1:2:1 (C) to 1:1:1 (D) reduced the ammonia emissions due to (1) a reduction in the pH and (2) the promotion of the growth of ammonia-oxidizing bacteria and the conversion of ammonium nitrogen to nitrate nitrogen. This study provides a theoretical basis and technical support for the odor problem of layer manure compost and promotes the development of composting technology.

Fasting-Induced Molting (FIM) has been shown to enhance the laying rate and extend the laying cycle of hens in the late laying period. However, the precise regulatory mechanism underlying FIM's effects on follicle development remains unknown. This study aimed to elucidate these mechanisms by utilizing RNA-seq to analyze the gene expression changes during FIM and identify the key genes involved in follicle development, thereby uncovering the molecular pathways through which FIM exerts its regulatory effects. A total of 96 Houdan hens, aged 326 days, were selected for FIM treatment. The results indicated a progressive increase in the number of small white follicles, as well as primary and secondary follicles, during the fasting and recovery phases. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and anti-Müllerian hormone (AMH) were reduced during the fasting period but gradually rebounded during refeeding. RNA sequencing and real-time quantitative PCR (qRT-PCR) analyses identified the PI3K-AKT signaling pathway as a crucial regulator of ovarian remodeling. Protein-Protein Interaction (PPI) analysis revealed that genes from the collagen family, particularly COL1A1, exhibit strong connectivity. In vitro experiments on cultured ovaries treated with varying concentrations of COL1A1 revealed that COL1A1 promotes ovarian cell proliferation, activates the PI3K-AKT signaling pathway, and upregulates the expression of GDF9 and BMP4. Masson staining results revealed significant collagen deposition in the ovary at the onset of FIM (F0), which was markedly reduced at F15. Collagen deposition re-emerged during the later stages of refeeding. In conclusion, this study identified the key genes regulating follicle development during the FIM and demonstrated that FIM can alleviate ovarian collagen deposition. These findings elucidate the molecular mechanism underlying FIM's regulatory effects on follicle development, providing a theoretical foundation for enhancing ovarian function in laying hens and optimizing FIM protocols.