Search

Body weight (BW) is an important economic trait in chickens. The hypothalamus serves as a central regulator of appetite and energy balance, and extensive research has demonstrated its pivotal role in regulating BW. However, the molecular network of the hypothalamus regulating BW traits in chickens needs to be further illuminated. In the present study, 200 1-day-old male 817 broilers were reared to 50 d of age, and BW were recorded. 20 birds with the lowest BW were classified as the low body weight group (L-BWG), and 20 birds with the highest BW were classified as the high body weight group (H-BWG). 18 hypothalamic tissue samples were collected, including 5 from the L-BWG, 5 from the H-BWG, and 8 from the middle weight range, and were analyzed using RNA-seq and weighted gene co-expression network analysis (WGCNA). Among the 18 RNA-seq samples, 5 samples from the L-BWG and 5 from the H-BWG were selected for differential expression gene analysis. Compared with the L-BWG, 195 and 1,241 genes were upregulated and downregulated in the H-BWG, respectively. The WGCNA analysis classified all co-expressed genes in the hypothalamus of 817 broilers into 20 modules. Among these modules, the pink module was identified as significantly negatively (r = -0.81, P = 4×10 -5 ) associated with BW. Furthermore, several genes, including Wnt family member 6 (WNT6), growth differentiation factor 11 (GDF11), bone morphogenetic protein 4 (BMP4), and erb-b2 receptor tyrosine kinase 4 (ERBB4), involved in "regulation of developmental process" and "response to growth factor," were identified as hub genes that contribute to the regulation of BW. These results provide valuable information for further understanding of the gene expression and regulation affecting BW traits and will contribute to the molecular breeding of chickens in the future., Competing Interests: DISCLOSURES The authors confirm that there are no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Carcass appearance is important economic trait, which affects customers in making purchase decisions. Both density and diameter of feather follicles are two important indicators of carcass appearance. However, the regulatory network and key genes be involved in feather follicle development remain poorly understood. To identify key genes and modules that involved in feather follicle development in chickens, 16 transcriptome datasets of Wannan chickens skin tissue (3 birds at the E9, E11, and E14, respectively, and 7 birds at the 12W) were used for weighted gene co-expression network analysis (WGCNA) analysis, and 12 skin tissue samples (3 birds for each stage) were selected for DEGs analysis. A total of 5,025, 2,337, and 10,623 DEGs were identified in 3 comparison groups, including the E9 vs. E11, the E11 vs. E14, and the E14 vs. 12W. Additionally, 31 co-expression gene modules were identified by WGCNA and the dark-orange, cyan, and blue module were found to be significantly associated with feather follicle development (p < 0.01). In total, 92,898 and 8,448 hub genes were obtained in the dark-orange, cyan, and blue modules, respectively. We focused on the cyan and blue modules, as 6 and 336 hub genes of these modules were identified to overlap with the DEGs of the three comparison groups, respectively. The 6 overlapped genes such as LAMC2, COL6A3, and COL6A2 etc., were over-represented in 12 categories such as focal adhesion and ECM-receptor interaction signaling pathway. Among the 336 genes that overlapped between the blue module and different DEGs comparison groups several genes including WNT7A and WNT9B were enriched in Wnt and ECM-receptor interaction signaling pathway. These results suggested that the LAMC2, COL6A3, COL6A2, WNT7A, and WNT9B genes may play a crucial role in the regulation of feather follicle development in Wannan chickens. Our results provided a reference for the molecular regulatory network and key genes in the development of feather follicles and contribute to molecular breeding for carcass appearance traits in chickens., Competing Interests: DISCLOSURES The authors confirm that there are no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Abdominal fat (AF) is one of the most important economic traits in chickens. Excessive AF in chickens will reduce feed utilization efficiency and negatively affect reproductive performance and disease resistance. However, the regulatory network of AF deposition needs to be further elucidated. In the present study, 300 one-day-old female Wannan chickens were reared to 17 wk of age, and 200 Wannan hens were selected to determine the abdominal fat percentage (AFP). Twenty AF tissue samples with the lowest AFP were selected as the low abdominal fat group (L-AFG), and 20 AF tissue samples with the highest AFP were selected as the high abdominal fat group (H-AFG). Eleven samples from L-AFG and 14 samples from H-AFG were selected for RNA-seq and used for weighted gene co-expression network analysis (WGCNA). Among the 25 RNA-seq samples, 5 samples with the lowest and highest AFP values were selected for differential expression gene analysis. Compared with the L-AFG, 225 and 101 genes were upregulated and downregulated in the H-AFG, respectively. A total of 20,503 genes were used to construct the WGCNA, and 44 co-expression gene modules were identified. Among these modules, 3 modules including turquoise, darkorange2, and floralwhite were identified as significantly associated with AFP traits. Furthermore, several genes including acyl-CoA oxidase 1 (ACOX1), stearoyl-CoA desaturase (SCD), aldehyde dehydrogenase 6 family member A1 (ALDH6A1), jun proto-oncogene, AP-1 transcription factor subunit (JUN), and fos proto-oncogene, AP-1 transcription factor subunit (FOS) involved in the "PPAR signaling pathway," "fatty acid metabolism," and "MAPK signaling pathway" were identified as central regulators that contribute to AF deposition. These results provide valuable information for further understanding of the gene expression and regulation of AF traits and contribute to future molecular breeding for AF in chickens., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Simple Summary: Weighted gene co-expression network analysis (WGCNA) was performed to investigate the gene networks and key genes involved in regulating inosine monophosphate (IMP) content in the pectoralis major muscle of the Guangde feathered-leg chicken breed. The study indicates that four genes in the purple module may be crucial in forming IMP content. This research enhances our understanding of the molecular mechanisms that contribute to IMP content. Inosine monophosphate (IMP) is a substance that enhances flavor and plays a crucial role in the umami taste of chicken muscle. It is also an influential factor in determining chicken's economic value. However, the molecular regulatory network underlying the IMP content in muscle remains unclear. To address this issue, we performed transcriptome sequencing on 20 pectoralis major muscle samples from 120-day-old Guangde feathered-leg chicken and used weighted gene co-expression network analysis (WGCNA) to identify key regulatory factors that influence IMP content. The weighted gene co-expression network was constructed using a total of 16,344 genes, leading to the identification of 20 co-expression gene modules. Among the modules that were identified, it was observed that the purple module (R = −0.51, p = 0.02) showed a significant negative correlation with the IMP content. This suggests that the genes within the purple module had the ability to regulate the IMP content. A total of 68 hub genes were identified in the purple module through gene significance (GS) > 0.2 and module membership (MM) > 0.8. The STRING database was used for a protein–protein interaction (PPI) network of hub genes. Furthermore, troponin I type 1 (TNNI1), myozenin 2 (MYOZ2), myosin light chain 2 regulatory cardiac slow (MYL2), and myosin light chain 3 regulatory cardiac slow (MYL3) involved in the "ATP-dependent activity", "cAMP signaling pathway" and "cGMP-PKG signaling pathway" were identified as central regulators that contribute to IMP content. These results offer valuable information into the gene expression and regulation that affects IMP content in muscle. [ABSTRACT FROM AUTHOR]