Lilong An

Chitosan oligosaccharides (COS) have antioxidant and immunomodulatory activities. This study characterized immune-organ responses associated with dietary COS in broilers exposed to cyclic heat stress (HS). A total of 192 birds were assigned to four groups (six cages/group; eight birds/cage): control (CON; 24 ± 1 °C), HS (34 ± 1 °C for 10 h/day), HS + 200 mg/kg COS, and HS + 400 mg/kg COS. Each treatment was replicated in three rooms, with two cages per room. One bird per cage was sampled after the final heat-stress bout and a 12 h fast (n = 6/group). Outcomes comprised organ indices and qualitative histology; serum corticosterone; splenic and thymic SOD, CAT, GSH-Px, and MDA; and heat-shock-, cytokine-, and apoptosis-related mRNA. Data were analyzed using a linear mixed model with treatment as a fixed effect and room nested within treatment as a random effect; Tukey-adjusted comparisons followed a significant omnibus test. Treatment was assigned at room level, the CON versus HS contrast was confounded with room temperature condition, and only three rooms were available per treatment, so all inferential comparisons are exploratory. Relative to unsupplemented HS, both COS doses increased spleen and bursa indices (p < 0.05), lowered serum corticosterone (p < 0.01), increased SOD and CAT activities (p < 0.01) and GSH-Px activity (p < 0.05), and lowered MDA (p < 0.05). COS groups also showed tissue- and dose-dependent shifts in mRNA. The 200 mg/kg group generally showed the largest reductions in pro-inflammatory transcripts, whereas 400 mg/kg produced the most consistent thymic apoptosis-related transcript pattern; no single dose was optimal across all endpoints. Dietary COS was therefore associated with altered immune-organ indices, measured oxidative status, and stress-, cytokine-, and apoptosis-related transcription under HS. Because no thermoneutral + COS group was included and room-level replication was limited, these findings require validation with replicated rooms, protein measurements, and functional immune endpoints.

Skeletal muscle, which is predominantly constituted by multinucleated muscle fibers, plays a pivotal role in sustaining bodily movements and energy metabolism. Myoblasts, which serve as precursor cells for differentiation and fusion into muscle fibers, are of critical importance in the exploration of the functional genes associated with embryonic muscle development. However, the in vitro proliferation of primary myoblasts is inherently constrained. In this study, we achieved a significant breakthrough by successfully establishing a chicken myoblast cell line through the introduction of the exogenous chicken telomerase reverse transcriptase (chTERT) gene, followed by rigorous G418-mediated pressure screening. This newly developed cell line, which was designated as chTERT-myoblasts, closely resembled primary myoblasts in terms of morphology and exhibited remarkable stability in culture for at least 20 generations of population doublings without undergoing malignant transformation. In addition, we conducted an exhaustive analysis that encompassed cellular proliferation, differentiation, and transfection characteristics. Our findings revealed that the chTERT-myoblasts had the ability to proliferate, differentiate, and transfect after multiple rounds of population doublings. This achievement not only furnished a valuable source of homogeneous avian cell material for investigating embryonic muscle development, but also provided valuable insights and methodologies for establishing primary cell lines.

Exosomes have the ability to transport RNA/miRNAs and possess immune modulatory functions. Heat stress, a significant limiting factor in the poultry industry, can induce oxidative stress and suppress the immune responses of laying hens. In this study, we investigated the expression profiles of serum exosomes and their miRNAs in Roman laying hens who were fed a diet with either 0 or 200 mg/kg curcumin under heat stress conditions. The numbers of exosomes were significantly higher in both the HC (heat stress) and HT (heat stress with 200 mg/kg curcumin) groups compared to the NC (control) group and NT (control with 200 mg/kg curcumin) group (p < 0.05). Additionally, we observed that the most prevalent particle diameters were 68.75 nm, 68.25 nm, 54.25 nm, and 60.25 nm in the NC, NT, HC, and HT groups, respectively. From our sRNA library analysis, we identified a total of 863 unique miRNAs; among them, we screened out for subsequent bioinformatics analysis a total of 328 gga-miRNAs(chicken miRNA from the miRbase database). The KEGG pathways that are associated with target genes which are regulated by differentially expressed miRNAs across all four groups at a p-value < 0.01 included oxidative phosphorylation, protein export, cysteine and methionine metabolism, fatty acid degradation, ubiquitin-mediated proteolysis, and cardiac muscle contraction. The above findings suggest that curcumin could mitigate heat-induced effects on laying hens by altering the miRNA expression profiles of serum exosomes along with related regulatory pathways.

The purpose of this study was to examine the effects of high temperature on internal egg yolk quality parameters and their possible mechanisms in Huaixiang chickens. This study consisted of two treatments, and each treatment had six replicates with six birds per cage. A total of seventy-two 26-week-old female Huaixiang chickens were randomly divided into a normal-temperature group (NT) and a high-temperature group (HT) for 6 weeks. And these hens were exposed to 25 ± 2 °C and 32 ± 2 °C, respectively. Their relative humidity was maintained at 55–65%. The results showed that the HT group significantly reduced yolk weight, yolk color, and egg weight compared to the NT group (p < 0.05). Heat stress caused vacuolar degeneration of the liver and reduced the absolute liver weight (p < 0.05). Both yolk triglyceride (TG) and liver TG in the HT group were significantly higher than in the NT group (p < 0.05). However, the liver total cholesterol (TC) level in the HT group was remarkably lower than that in the NT group (p < 0.05). Additionally, heat stress remarkably enhanced SREBP-1c, ACACA, and FASN lipid metabolism-related gene mRNA expression levels in Huaixiang chicken liver after 6 weeks of heat exposure (p < 0.05). Furthermore, the HT group had remarkably reduced total amino acid, Cys, and Tyr levels in the yolk when compared with the NT group in our experiment (p < 0.05). In conclusion, heat stress causes egg yolk quality reduction and abnormal lipid metabolism in Huaixiang chickens. These findings provided novel insights into the role of high temperature on egg yolk parameters and the underlying mechanisms in Chinese indigenous laying hens.

The quality and quantity of animal meat are closely related to the development of skeletal muscle, which, in turn, is determined by myogenic cells, including myoblasts and skeletal muscle satellite cells (SMSCs). Circular RNA, an endogenous RNA derivative formed through specific reverse splicing in mRNA precursors, has the potential to influence muscle development by binding to miRNAs or regulating gene expression involved in muscular growth at the transcriptional level. Previous high-throughput sequencing of circRNA in chicken liver tissue revealed a circular transcript, circIGF2BP3, derived from the gene encoding insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3). In this study, we confirmed the presence of the natural circular molecule of circIGF2BP3 through an RNase R enzyme tolerance assay. RT-qPCR results showed high circIGF2BP3 expression in the pectoral and thigh muscles of Yuexi frizzled feather chickens at embryonic ages 14 and 18, as well as at 7 weeks post-hatch. Notably, its expression increased during embryonic development, followed by a rapid decrease after birth. As well as using RT-qPCR, Edu, CCK-8, immunofluorescence, and Western blot techniques, we demonstrated that overexpressing circIGF2BP3 could promote the proliferation and differentiation of chicken primary myoblasts through upregulating genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1), cyclin E1 (CCNE1), cyclin dependent kinase 2 (CDK2), myosin heavy chain (MyHC), myoblast-determining 1 (MyoD1), myogenin (MyoG), and Myomaker. In conclusion, circIGF2BP3 promotes the proliferation and differentiation of myoblasts in chickens. This study establishes a foundation for further investigation into the biological functions and mechanisms of circIGF2BP3 in myoblasts proliferation and differentiation.

The anterior pituitary gland of animals secretes growth hormone (GH) to bind to the growth hormone receptor (GHR) on the liver cell membrane through the blood circulation, thereby promoting the downstream gene insulin-like growth factor-1 (IGF1) expression, which is the canonical GH–GHR–IGF1 signaling pathway. Therefore, the amount of GHR and the integrity of its structure will affect animal growth and development. In the previous study, we found that the mouse GHR gene can transcribe a circular transcript named circGHR. Our group cloned the full-length of the mouse circGHR and analyzed its spatiotemporal expression profile. In this study, we further predicted the open reading frame of circGHR with bioinformatics, subsequently constructed a Flag-tagged protein vector and preliminarily verified its coding potential with western blot. Additionally, we found that circGHR could inhibit the proliferation of NCTC469 cells and has a tendency to inhibit cell apoptosis, while for C2C12 cells, it showed a tendency to inhibit cell proliferation and promote its differentiation. Overall, these results suggested that the mouse circGHR had the potential to encode proteins and affect cell proliferation, differentiation and apoptosis.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) disrupts the blood-testis barrier (BTB), resulting in alterations in spermatogenesis. However, whether BTB-related proteins (such as ZO-1, claudin11, N-cadherin, and CX43) are targeted by SARS-CoV-2 remains to be clarified. BTB is a physical barrier between the blood vessels and the seminiferous tubules of the animal testis, and it is one of the tightest blood-tissue barriers in the mammalian body. In this study, we investigated the effects of viral proteins, via ectopic expression of individual viral proteins, on BTB-related proteins, the secretion of immune factors, and the formation and degradation of autophagosomes in human primary Sertoli cells. Our study demonstrated that ectopic expression of viral E (envelope protein) and M (membrane protein) induced the expressions of ZO-1 and claudin11, promoted the formation of autophagosomes, and inhibited autophagy flux. S (spike protein) reduced the expression of ZO-1, N-cadherin, and CX43, induced the expression of claudin11, and inhibited the formation and degradation of autophagosomes. N (nucleocapsid protein) reduced the expression of ZO-1, claudin11, and N-cadherin. All the structural proteins (SPs) E, M, N, and S increased the expression of the FasL gene, and the E protein promoted the expression and secretion of FasL and TGF-β proteins and the expression of IL-1. Blockage of autophagy by specific inhibitors resulted in the suppression of BTB-related proteins by the SPs. Our results indicated that SARS-CoV-2 SPs (E, M, and S) regulate BTB-related proteins through autophagy.

This study was conducted to investigate the effects of dietary curcumin on the hepatic lipid metabolism and antioxidant capacity in Roman laying hens. A total of 144 Roman laying hens (28 weeks old) were allocated 4 dietary treatments that included curcumin at concentrations of 0, 50, 150, and 250 mg/kg for 9 weeks. Each treatment had 6 replicates per group with 6 hens per replicate (2 birds/cage). The results showed that dietary supplementation of curcumin decreased (P < 0.05) the absolute and relative abdominal fat weight during 32–34 wk. Curcumin supplemented at 150 mg/kg had been reduced (P < 0.05) the concentrations of triglycerides (TG) and total cholesterol in plasma, the liver TG concentrations, and the enzyme activities of malic (ME) and lipoprotein lipase of Roman laying hens throughout the experiment. Curcumin supplemented also decreased (P < 0.05) the mRNA expression of Sterol expression-regulatory protein-1c (SREBP-1c), ACC, FAS, ME and while it increased the mRNA expression of Apolipoprotein B-100 and Apolipoprotein-II. Further research found that dietary curcumin boosted the activity of the antioxidant enzymes Superoxide dismutase, Catalase, and Glutathione peroxidase in plasma and liver. It lowered the levels of Malondialdehyde in plasma and liver. In conclusion, curcumin inclusion regulated the hepatic fat metabolism, reduced abdominal fat deposition and improved the antioxidant capacity of Roman laying hens.