Wooden breast (WB) myopathy is a common myopathy found in commercial broiler chickens worldwide. Although extensive research on WB has been conducted using transcriptomics, effectively screening and ...analyzing key target information remains a challenge. In this present study, 5 transcriptomic datasets obtained from the National Center for Biotechnology Information (NCBI) were used. A meta-analysis was conducted to identify meta-differentially expressed genes (meta-DEGs) involved in the response of broilers to WB myopathy. These meta-DEGs were further analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA), supplemented by protein-protein interaction (PPI) network construction to pinpoint hub genes. These analyses help to reveal key genes, pathways, and biological processes associated with WB myopathy. The results showed that 646 up-regulated and 99 down-regulated significant meta-DEGs (|log2FC| ≥0.6, P-Meta < 0.05, and present in at least 4 datasets) were identified. GO analysis showed that multiple fibrosis-related pathways/biological processes, such as cell adhesion, connective tissue development, and collagen-rich extracellular matrix, as well as calcium ion binding were significantly upregulated. PPI analysis identified TGFB3, COL1A1, COL1A2, and COL3A1 as central hub genes involved in the fibrotic processes. KEGG analysis revealed significant upregulation of apoptosis and lysosomal pathways, with an enrichment of Ca2+-related signals and lysosomal cathepsins within the apoptosis pathway. Additionally, GSEA indicated a suppression of the tricarboxylic acid (TCA) cycle and the mitochondrial electron transport chain (ETC) in WB myopathy, with PPI analysis also identifying specific hub genes associated with these pathways.
In conclusion, our comprehensive analysis of meta-DEGs elucidated key biological processes and pathways implicated in WB myopathy, including fibrosis, apoptosis, altered calcium signaling, and metabolic disruption. The identification of specific hub genes offers avenues for further investigation into the pathogenesis of this condition, potentially guiding targeted therapeutic strategies.
Heat stress induces mitochondrial dysfunction, thereby impeding skeletal muscle development and significantly impacting the economic efficiency of poultry production. This study aimed to investigate ...the effects of embryo thermal manipulation (TM, 41.5°C, 65% RH, 3 h/d during 16–18th embryonic age) on the mitochondrial function of the pectoralis major (PM) in broiler chickens exposed to thermoneutral (24 ± 1°C, 60% RH) or cyclic heat stress (35 ± 1°C, 60% RH, 12 h/d) from day 22 to 28, and to explore potential mechanisms involving transient receptor potential V2 (TRPV2). Additionally, in vitro experiments were conducted to assess the regulatory effects of TRPV2 pharmacological activation and inhibition on mitochondrial function in primary myotubes. The results revealed that TM had no discernible effect on the body weight and feed intake of broiler chickens under heat stress conditions (P > 0.05). However, it did delay the increase in rectal temperature and accelerate the decrease in serum T3 levels (P < 0.05). Furthermore, TM promoted the development of PM muscle fibers, significantly increasing myofiber diameter and cross-sectional area (P < 0.05). Under heat stress conditions, TM significantly upregulated the expression of mitochondrial electron transport chain (ETC) genes and TRPV2 in broiler PM muscle (P < 0.05), with a clear positive correlation observed between the two (P < 0.05). In vitro, pharmacological activation of TRPV2 not only increased its own expression but also enhanced mitochondrial ETC genes expression and oxidative phosphorylation function by upregulating intracellular calcium ion levels (P < 0.05). Conversely, TRPV2 inhibition had the opposite effect. Overall, this study underscores the potential of prenatal thermal manipulation in regulating postnatal broiler skeletal muscle development and mitochondrial function through the modulation of TRPV2 expression.
White striping (WS) that appears as white stripes parallel to the muscle fibrils is an emerging growth-related abnormality of broiler breast meat. The pathomechanism of this defect has not been fully ...understood despite intensive studies over the past decade. In the present study, endoplasmic reticulum (ER) stress and its associated apoptotic pathways were investigated to elucidate the potential role of these pathways in the development of WS. To this end, a total of 60 Pectoralis major (Pm) muscle samples were collected from 55-d-old Ross 308 male broiler chickens according to the severity of gross WS lesions (normal, mild, and severe). Histopathological and molecular analyses were conducted to evaluate the lesions and genes involved in the ER stress and related apoptosis. All the Pm samples, both with and without macroscopic WS lesions, showed varying degrees of myodegenerative lesions. Molecular analysis revealed that the transcript abundances of many components related to protein kinase R-like ER kinase (PERK) and inositol-requiring enzyme type 1 (IRE-1) signals of the ER stress response were significantly greater in severely WS-affected breast tissues compared to their mildly affected and normal counterparts. Similarly, the transcript abundances of apoptotic markers related to both signaling pathways were significantly greater in severe WS lesions than those of mildly affected and normal Pm tissues. Besides these, a significant increase in caspase-3 transcript abundance was seen in severe WS lesions in comparison with mild WS and normal breast muscles. Findings of this study suggest that ER stress response and its related apoptotic pathways are possibly activated in the breast muscle of broiler chickens with severe WS lesions. Based on these findings, it is speculated that ER stress-mediated apoptosis occupies a central role in the progression of WS in broiler chickens.
Previously, we reported that glucagon-like peptide-1 (GLP-1) and its analog liraglutide could inhibit fat de novo synthesis in the liver and reduce abdominal fat accumulation in broiler chickens. ...Nevertheless, the impact of GLP-1 on adipocyte fat deposition remains enigmatic. This study aimed to investigate the effects of GLP-1, via its analog liraglutide, on chicken chicken adipocytes in vitro. Chemical assays, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot were employed to assess the proliferation, differentiation, and fat deposition of chicken adipocytes. Our findings indicated that liraglutide significantly suppressed cell proliferation and promoted preadipocyte differentiation in comparison to the control group. This was evidenced by elevated triglyceride (TG) content and upregulated mRNA expression of lipogenesis-related enzymes, such as acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), as well as regulators including peroxisome proliferator-activated receptor γ (PPARγ), sterol regulatory element binding protein-1 (SREBP1) and CCAAT/enhancer binding protein α (CEBPα). In mature adipocytes, liraglutide attenuated fat deposition by inhibiting fat de novo synthesis, evidenced by decreased mRNA expression of ACC, FAS, PPARγ, C/EBPα, and SREBP1, and concurrent upregulation of phosphorylated AMP-activated protein kinase (p-AMPK) and phosphorylated ACC (p-ACC). This resulted in reduced accumulation of lipid droplets and TG content in mature adipocytes. Collectively, our findings indicate that liraglutide suppresses the proliferation of preadipocytes, enhances their differentiation, and concurrently inhibits de novo lipogenesis in mature adipocytes. This observation offers profound insights into the mechanisms that underlie liraglutide's anti-adipogenic effects, which could have significant implications for the treatment of obesity in broiler chickens.
Feed restriction could induce physiological stress in broiler chickens, leading to welfare issues. Prenatal stimulation could improve stress-coping mechanisms in poultry. The present study aimed to ...elucidate the effects of subjecting developing embryos to auditory stimulation on physiological stress response to feed restriction in broiler chickens at market age. A total of 423 hatching eggs of Cobb 500 (Gallus domesticus) were subjected to the following auditory treatments: 1) no additional sound treatment other than the background sound of the incubator's compressors at 40 dB (CONTROL), 2) exposure to pre-recorded traffic noise at 90 dB (NOISE), and 3) exposure to Mozart's Sonata for Two Pianos in D Major, K 488 at 90 dB) (MUSIC). The NOISE and MUSIC treatments were for 20 min/h for 24 h (a total of 8 h/d), starting from embryonic days (ED) 12 to hatching. On d 42, an equal number of birds from each prenatal auditory stimulation (PAS) group were subjected to either ad libitum feeding (AL) or 30-h of feed restriction (FR) in a completely randomised design. The FR chickens exhibited significantly higher serum levels of corticosterone (CORT), and heat shock protein (HSP) 70 compared to those of AL. Prenatal auditory stimulation, particularly NOISE, led to lower serum levels of CORT and alpha-1-acid glycoprotein (AGP) levels compared to the CONTROL group. Additionally, NOISE significantly increased brain mRNA glucocorticoid receptor and HSP70 gene expression. The cecal population of E. coli and Lactobacillus spp. was not significantly affected by prenatal auditory stimulation. In conclusion, our findings suggest that prenatal auditory stimulation, particularly NOISE, positively impacts broiler chickens' ability to cope with feed restriction.
In poultry industry, the strategies for elevating of protein accretion with minimizing fat deposition have been applied, and seaweed algae has been focused one of the potential candidates. ...Accordingly, the purpose of this study was to investigate the effects of algae (Ascophllum Nodosum) extract (AE) on the growth performance and body composition of broiler chickens. A total of 240 one-day-old Ross 308 broiler chickens were allotted to 4 dietary treatment groups and fed experimental diets containing different concentrations of AE for 35 d as follows: 0 mg/kg (control, CON), 1,250 mg/kg (LAE), 2,500 mg/kg (MAE), or 5,000 mg/kg (HAE). At the end of the experiment, 40 chickens were sacrificed and samples of their blood, breast muscle, liver, and abdominal fat were collected and analyzed. Growth performance was improved in the LAE group compared to that in the CON (P < 0.05). The weight of abdominal fat was lower in the HAE group than in the CON group (P < 0.05). Serum triglyceride levels were also decreased in the HAE group compared to those in the CON and LAE groups (P < 0.05). Adipocytes were smaller in the HAE group than in all other treatments, and their size distribution was shifted more towards smaller adipocytes compared to those in the LAE group (P < 0.05). Relative mRNA levels in abdominal adipose tissue of fatty acid synthase and stearyl-CoA desaturase, which are involved in fatty acid synthesis, were all downregulated by supplementation with AE (P < 0.05). In addition, the protein levels of peroxisome proliferator-activated receptor gamma were decreased and the ratio of phosphorylated acetyl-CoA carboxylase to total ACC was increased, both of which indicate that lipogenesis was suppressed (P < 0.05). Hepatic transcript levels of sterol regulatory element-binding protein and its downstream enzymes fatty acid synthase and sterol-CoA desaturase were also lower in all AE treatments compared to those in the CON group (P < 0.05). These results indicate that the seaweed algae (Ascophllum Nodosum) extract reduces fat accumulation in both adipose tissue and the liver by modulating lipogenesis.
Good slaughter hygiene and accurate meat inspection in slaughterhouses (SHs) should ensure the hygienic quality of broiler chicken (broiler) carcasses accepted as food and guarantee that broiler meat ...from the carcasses is safe and fit for human consumption. The purpose of our research was to 1) determine the visible hygienic quality of broiler carcasses by visual inspection, 2) compare the results between the large Finnish SHs, and 3) determine the effectivity of the post-mortem inspection (PMI). We additionally aimed to study whether the requirement to inspect the body cavities of all carcasses during the PMI has had any impact on the visible hygienic quality of broiler carcasses in the SHs. The study was divided into two parts. In study 1, one researcher (the first author) inspected 2200 carcasses after PMI in three SHs and detected that, depending on the SH, 0.7–3.6% of carcasses had faecal contamination, 0.4–2.0% had gastrointestinal (GI) tract parts, 0.1–3.6% had some other form of contamination or other inedible remnants, and 0.2–0.5% showed pathological or organoleptic changes. Study 1 was carried out 2019, before the inspection of the body cavities of all carcasses was in use in PMI in the SHs.
One SH had significantly higher prevalences of carcasses with faecal contamination (P < 0.001 &P = 0.002) and residual GI tract parts (P = 0.004 &P = 0.006) than the other two SHs. The visual inspection in study 2 was performed 2020–2022 after the inspection of the external surfaces of all carcass body cavities had been included in PMI or after it was as a part of an own-check system. Only one SH had lower prevalences of carcasses with faecal contamination and residual GI tract parts (P = 0.009 &P = 0.005, respectively) in study 2 than in study 1. In all SHs, faeces were mostly found within the body cavities in both studies highlighting the importance of carcass body cavity inspection. A zero level of faecal contamination was not achieved in any SH. Assessing the visible hygienic quality of carcasses enables to assess the differences between SHs in slaughter hygiene management, enabling the risk categorization of SHs, along with assessing the efficiency of PMI.
•Visible faecal contamination was mostly within carcass body cavities.•A zero level of faecal contamination was not achieved in any of the slaughterhouses.•Local inflammation or soiling on carcasses may go unnoticed during post-mortem inspection.•Body cavity inspection is essential to find contamination and remaining visceral parts.•Process hygiene differences between slaughterhouses can be verified by visual carcass inspection.
•Nutritional value of Tenebrio molitor (TM) and Hermetia illucens (HI) was studied.•Total tract apparent digestibility of both TM and HI meal was determined.•Total tract apparent metabolizable energy ...of both TM and HI meal was determined.•Apparent ileal amino acid digestibility both TM and HI meal was determined.
The aim of this study was to determine the apparent digestibility coefficients of the total tract (CTTAD) of nutrients and the apparent metabolizable energy (AME and AMEn) of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens. The amino acid (AA) apparent ileal digestibility coefficients (AIDC) was also determined. The experimental diets were: a basal diet and two diets prepared by substituting 250g/kg (w/w) of the basal diet with Tenebrio molitor meal (TM) or Hermetia illucens meal (HI). No statistical difference was found between the two insect larval meals for the CTTAD of the nutrients, except for the CTTAD for ether extract (P<0.001) where the HI meal proved to be more digestible than the TM meal (0.99 and 0.88, respectively). The CTTAD for DM was 0.60 and 0.53; 0.66 and 0.66 for OM; 0.60 and 0.51 for CP, whereas it was 0.64 and 0.69 for GE, for TM and HI, respectively. No difference was observed between TM and HI (P>0.05) for AME or AMEn (AME=16.86 and 17.38MJ/kg DM, respectively; AMEn=16.02 and 16.60MJ/kg DM, respectively). The average AIDC of the 17 analyzed AAs was higher (P<0.001) in TM than in HI (0.86 and 0.68, respectively) because the AIDC of isoluecine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glycine, glutamic acid and tyrosine was higher (P<0.05) in TM than in HI. Overall, the present results have shown that TM and HI meals are excellent sources of AME for broilers and a valuable source of digestible AA, particularly as far as TM meal is concerned.
Meat inspection of broiler chickens (broiler) in the European Union is regulated by common legislation to secure meat safety. However, the legislation is general in nature and proper post-mortem ...inspection (PMI) of every carcass and visceral organs of broilers is challenging in slaughterhouses (SHs) with a high slaughter line speed. The aim of this study was to investigate the on-site organization and possible differences of the PMI in four Finnish SHs, which slaughter over 99% of broilers in Finland. Our results show that the meat inspector's available inspection time per broiler in the PMI varied between 0.28 and 0.90 s, with the shortest available inspection time in the SH with the highest slaughter line speed and the longest available inspection time in the SH with the slowest line speed. We observed that only part of the total inspection time per broiler could be used for true PMI in most (3/4) SHs, as the meat inspectors also performed other tasks during the PMI. We observed deficiencies in the visual inspection of broiler carcasses; in particular, the proper inspection of all or most of the body cavities was impossible in all SHs during the PMI. Some deficiencies in facilities (e.g. in recording system) were observed. Moreover, lighting properties varied between the SHs and a significant difference between illumination conditions at the first inspection stations in the SHs was observed. This study considered the prerequisites for proper PMI and revealed that the PMI of broilers was not completely uniform in Finland. The results emphasize the need for more precise guidelines and recommendations, especially for inspection time and lighting at inspection stations.
•A short post-mortem inspection time may hamper detection of non-acceptable broilers.•Differences in facilities and lighting affected post-mortem inspection uniformity.•Measurements can be used to evaluate the uniformity of meat inspection stations.•The high line speed of slaughterhouses hinders proper inspection of body cavities.
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