Hydrogen Peroxide-Induced Change in Meat Quality of the Breast Muscle of Broilers Is Mediated by ROS Generation, Apoptosis, and Autophagy in the NF-κB Signal Pathway

Effects of mitochondrial lipidome alterations on quality deterioration of Larimichthys crocea postmortem storage: New insight from the perspective of mediating mitochondria-dependent apoptosis

Apoptosis occurs in the myocyte of fish postmortem storage. Based on the important role of mitochondrial lipid molecules in regulating apoptosis, the study aims to investigate the potential impact of mitochondrial lipids on apoptosis and quality deterioration of large yellow croaker. A total of 1079 lipid molecule species in 13 classes were identified in mitochondria. PC and PE decreased by 17.40 % and 28.31 % at 24 h, which induces mitochondrial damage and induces oxidative stress. Cytochrome c induced CL oxidation mediated by ROS (Oxidized CL increased by 30.65 %), resulting in cytochrome c release and activates caspase-3. The cytochrome c of cytoplasm and caspase-3 activity increased by 79.32 % and 82.72 % from 0 to 24 h, which led to significant apoptosis. Accumulation of ROS and activated caspase-3 during apoptosis induced muscle oxidation and softening. These findings provide new insights into the relationship between mitochondrial lipid changes and apoptosis and quality deterioration in fish postmortem storage.

Minimizing food oxidation using aromatic polymer: From lignin into nano-lignin

Food loss and waste caused by oxidation result in environmental and economic losses and health threats. Lignin is an abundant aromatic polymer with varied antioxidant capacity, which can reduce food oxidation caused by radical species exposure. The lignin antioxidant strength can be influenced by source, type, structure, processing, degradation products, chemical modifications, and particle size. Lignin in micro- or nano-particles has high reactivity and is associated with increased surface area to improve antioxidant capacity. Lignin can be used as a food additive to suppress lipid and protein oxidation, although its effect on fruit/vegetable oxidation needs to be discussed. The lignin antioxidant properties are promising to be applied in food industries, such as food additives, animal feed supplements, and antioxidant packaging designs. However, there are challenges and limitations to consider, such as the potential for toxicity reactions in some individuals and the need for further research to understand its effects on different food products fully. As a feed nutrition, lignin can improve meat quality. Meanwhile, loading lignin in the packaging matrix can extend the food shelf life through antioxidant and antimicrobial activities, and UV-block. Lignin also improves packaging properties (conventional and 3D-printing fabrication) to maintain food quality, e.g., changes in mechanical properties, hydrophobicity, water vapor permeability, and other influences. This article reviews lignin's role as a natural antioxidant in the food industry. Future directions and discussions relate to prooxidative mechanisms, toxicity, fruit and vegetable preservation mechanisms, inhibition of protein oxidation, activity to food enzymes (fruit ripening enzyme activators and inhibitors of cellulase and β-glucosidase enzyme), dispersity in packaging matrices, and material diversification for 3D printing.

Effects of 1-Deoxynojirimycin Extracts of Mulberry Leaves on Oxidative Stress and the Function of the Intestinal Tract in Broilers Induced by H2O2

The poultry industry struggles with oxidative stress affecting gut health and productivity. This study examined using 1-Deoxynojirimycin (DNJ) extracts from mulberry leaves as an antioxidant in broilers feed to combat this issue. We divided 240 broilers, aged 16 days, into six groups, including a control and groups exposed to oxidative stress through H2O2 injections, with different supplement levels of DNJ-E (40, 80, 120, and 160 mg/kg of the basal diet) lasting until the broilers reached 42 days old. We evaluated intestinal morphology, ultrastructure, oxidative stress markers, the tight junction, and inflammatory cytokines. Adding 40 mg/kg DNJ-E improved villus height, the villus-to-crypt ratio, and cellular ultrastructure, and increased SOD levels in the jejunum and ileum, as well as CAT levels in the duodenum and jejunum (p < 0.05), compared to the H2O2 group. The addition of DNJ had differential effects on oxidative stress, the intestinal barrier, and immune-related genes. Importantly, the dosages of 40 mg/kg and 80 mg/kg resulted in an upregulation of MUC2 mRNA expression (p < 0.05). These findings suggest that DNJ-E holds potential as a beneficial feed additive for enhancing broiler health, particularly at supplementation levels below 80 mg/kg, as higher concentrations may negatively influence intestinal health. Future investigations should aim to elucidate the underlying mechanisms through which DNJ-E operates within the avian gastrointestinal system.

The toxic effects of exposure to fibrous and fragmented microplastic in juvenile rockfish based on two omics approach

Although the hazards of environmental microplastics (MPs) are well known, it is unclear which of their characteristics have the greatest effects on organism. We investigated the toxic effects of oral administration according to physical properties, including the shape of fragmented polyethylene terephthalate (PET) (FrPET) and fibrous PET (FiPET) MPs. After 72 h of exposure, apoptosis and phagocytic activity varied significantly among juvenile rockfish (Sebastes schlegeli) exposed to both FrPET and FiPET. The levels of immune-related genes and hepatic metabolic activity also increased after exposure to both shapes of MPs, but the variation in responses was greater in fish exposed to FiPET compared with those exposed to FrPET. The transcriptomic and metabolomics analysis results indicated that the maintenance and homeostasis of immune system was affected by oral exposure to FrPET and FiPET. The amino acid metabolic processes were identified in rockfish exposed to FrPET, but the notch signaling pathway were evident in the FiPET exposure group. Metabolomics analysis revealed that oral ingestion of MP fibers led to a stronger inflammatory response and greater oxidative stress in juvenile rockfish. These results can be used to understand environmentally dominant MP toxic effects such as type, size, shapes, as well as to prioritize ecotoxicological management.

The Activation of Endogenous Proteases in Shrimp Muscle Under Water-Free Live Transport

Water-free transportation (WFT) causes shrimp (Penaeus vannamei) flesh quality deterioration. However, the roles of endogenous protease-induced protein hydrolysis have been neglected in the research. In the present study, calpain zymography, gelatinase zymography, the hematoxylin-eosin staining method, and other methods were applied to investigate the response of various endogenous proteases (cathepsin, calpain, and gelatinase), the myofibril fragmentation index (MFI), and the microscopic morphology of shrimp muscle during WFT in comparison with the shrimp under the conventional water transportation strategy (WT). The results showed that the total activity of proteases in shrimp muscle increased significantly (p ≤ 0.05) after simulated transportation. Cathepsins and gelatinases were activated during WFT. No significant (p > 0.05) changes of the activity of caspase-3 and the muscle cell apoptosis rate were detected in shrimp muscle cells after WFT. In addition, the MFI increased and the gap among muscle fiber bundles enlarged after WFT. Compared with WFT, no significant (p > 0.05) effect on the activities of calpain, gelatinase, and caspase-3 in the muscle of shrimp was found after WT, and only the activity of cathepsin L significantly increased (p ≤ 0.05). Based on the findings, we concluded that the activation of various endogenous proteases was induced during WFT.

Effects of Se-enriched yeast on the amelioration of atrazine-induced meat quality degradation

Atrazine (ATR) is herbicide that causes serious harm to the environment and threatens human food safety. Se-enriched yeast is the best organic selenium source for protecting cells from damage caused by poisonous substances. To explore mechanism of ATR on meat quality degradation and potential protective effects of Se-enriched yeast on ATR-induced muscle injury, quails were treated with ATR and/or Se-enriched yeast for 28 days. The results found ATR disrupted muscle fiber structure and decreased pH, tenderness, water-holding capacity, essential amino acid content and polyunsaturated fatty acid content. ATR aggravated oxidative stress and inflammation by inhibiting Nrf2 pathway and activating NF-κB pathway, ultimately causing apoptosis. However, Se-enriched yeast alleviated ATR-induced alterations in muscle chemical and physical properties by inhibiting oxidative stress and inflammation. Taken together, these results revealed that ATR exposure caused meat quality degradation and Se-enriched yeast had the potential to counteract ATR-induced myotoxicity by inhibiting oxidative stress and inflammation.

Protective Effect of Epigallocatechin-3-gallate against Hepatic Oxidative Stress Induced by tert-Butyl Hhydroperoxide in Yellow-Feathered Broilers

Recent studies have shown that epigallocatechin-3-gallate (EGCG), as an effective antioxidant, could attenuate the oxidative damage, inflammation and necrosis in the liver in response to oxidative stress. The present study investigated whether oral administration of EGCG could effectively alleviate the hepatic histopathological changes and oxidative damage in yellow-feathered broilers induced by tert-butyl hydroperoxide (t-BHP). Broilers were exposed to 600 μmol t-BHP/kg body weight (BW) to induce oxidative stress by intraperitoneal injection every five days, followed by oral administration of different doses of EGCG (0, 20, 40 and 60 mg/kg BW) and 20 mg vitamin E (VE)/kg BW every day during 5-21 days of age. The results showed that t-BHP injection decreased (p < 0.05) body weight and the relative weight of the spleen; the enzyme activities of total antioxidant capacity (T-AOC), catalase (CAT) and total superoxide dismutase (SOD); and gene mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), CAT, SOD1, SOD2 and acetyl-CoA carboxylase (ACACA); as well as increased (p < 0.05) necrosis formation, malondialdehyde (MDA) content, reactive oxygen species (ROS)accumulation, and peroxisome proliferator activates receptor-α (PPARα) mRNA expression in the liver of yellow-feathered female broilers at 21 days of age. Treatment with 60 mg EGCG/kg BW orally could enhance antioxidant enzyme activities and reverse the hepatic damage induced by t-BHP injection by reducing the accumulation of ROS and MDA in the liver and activating the Nrf2 and PPARα pathways related to the induction of antioxidant gene expression (p < 0.05). In conclusion, intraperitoneal injection of t-BHP impaired body growth and induced hepatic ROS accumulation, which destroyed the antioxidant system and led to oxidative damage in the liver of yellow-feathered broilers from 5 to 21 days of age. It is suggested that EGCG may play an antioxidant role through the Nrf2 and PPARα signaling pathways to effectively protect against t-BHP-induced hepatic oxidative damage in broilers, and the appropriate dose was 60 mg EGCG/kg BW by oral administration.

Effects of gossypol acetate on growth, serum biochemical parameters, and intestinal health of goslings

Free gossypol (FG), the primary antinutritional component in cottonseed meal, can adversely affect the growth and health of poultry. Although younger geese are particularly sensitive to FG, the precise effects of FG on geese remain elusive. This study aimed to investigate the effects of gossypol acetate (GA), a form of FG, on the growth, serum biochemical parameters, and intestinal health of goslings. Seventy-two healthy male goslings, aged 7-day-old with similar body weight (BW), were randomly divided into 3 groups: a control group and 2 GA-treated groups (GA25 and GA50), which were orally administered GA (25 and 50 mg/kg BW) daily for 14 d. The results showed that oral administration of GA significantly suppressed BW, altered serum parameters, and impaired intestinal health in a dose- and time-dependent manner. Specifically, GA adversely affected intestinal morphology, induced oxidative stress, and inflammation, diminished immune function, and increased intestinal permeability and apoptosis of intestinal cells, consequently impairing nutrient absorption and utilization of goslings. Overall, these data indicate that GA adversely affects the growth, serum parameters, and intestinal health of goslings, providing valuable information further to understand the toxic effects of gossypol on goslings.

Insights into the effects of saline forage on the meat quality of Tibetan sheep by metabolome and multivariate analysis

This work aimed to investigate how two different types of forage (saline and alkaline) impact the meat quality and muscle metabolism of Tibetan sheep. An integrative multi-omics analysis of meat quality and different metabolites was performed using untargeted and targeted metabolomics approaches. The research results indicated that GG grass (saline and alkaline forage) possessed superior characteristics in terms of apparent quality and secondary metabolite content compared with HG grass (Non saline alkali forage), regardless of the targeted metabolites or non-targeted ones. Simultaneously, under stress conditions, the carbohydrates-rich salt-alkali grass play a significant role in slowing down the decline in pH, increasing the unsaturated fatty acid content and reducing the thawing loss in Tibetan sheep. This study provides an understanding of the impact of different salt-alkali grass on the quality of Tibetan sheep meat, while providing a scientific basis for the future development of salt-alkali livestock industry.

New perspective for Calpain-Mediated regulation of meat Quality: Unveiling the impact on mitochondrial pathway apoptosis in post-mortem

While calpain's role in myofibrillar protein degradation is well-established, its impact on post-mortem apoptosis remains fully elucidated. This study aimed to examine how calpain influences the mitochondrial apoptotic pathway in post-mortem muscle cells and assess its potential impact on chicken tenderness. The findings indicate that the calpain inhibitor treatment could decelerate the rate of lysosome destruction in post-mortem chicken, which is a crucial factor in delaying the mitochondrial apoptotic pathway. Subsequently, this inhibition enhanced the mitochondrial membrane's stability and suppressed the apoptosis-inducing factor Cyt c release into the sarcoplasm. The Western blot results in a greater myofibrillar protein degradation degree in the caspase inhibitor samples compared to the calpain inhibitor samples. Interestingly, the two groups had no significant difference in shear force. Based on these reasons, a novel perspective was introduced in this paper: Calpain could affect the change in meat tenderness by regulating mitochondrial apoptosis in the post-mortem period.

Insights into the mechanism of L-malic acid on drip loss of chicken meat under commercial conditions

BACKGROUND

A deterioration in the meat quality of broilers has attracted much more attention in recent years. L-malic acid (MA) is evidenced to decrease meat drip loss in broilers, but the underlying molecular mechanisms are still unclear. It's also not sure whether the outputs obtained under experimental conditions can be obtained in a commercial condition. Here, we investigated the effects and mechanisms of dietary MA supplementation on chicken meat drip loss at large-scale rearing.

RESULTS

Results showed that the growth performance and drip loss were improved by MA supplementation. Meat metabolome revealed that L-2-aminoadipic acid, β-aminoisobutyric acid, eicosapentaenoic acid, and nicotinamide, as well as amino acid metabolism pathways connected to the improvements of meat quality by MA addition. The transcriptome analysis further indicated that the effect of MA on drip loss was also related to the proper immune response, evidenced by the enhanced B cell receptor signaling pathway, NF-κB signaling pathway, TNF signaling pathway, and IL-17 signaling pathway.

CONCLUSIONS

We provided evidence that MA decreased chicken meat drip loss under commercial conditions. Metabolome and transcriptome revealed a comprehensive understanding of the underlying mechanisms. Together, MA could be used as a promising dietary supplement for enhancing the water-holding capacity of chicken meat.

Coated oregano essential oil and cinnamaldehyde compounds supplementation improves growth performance, enhances immune responses, and inhibits cecal Escherichia coli proliferation of broilers

Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into 5 groups: 1) negative control fed basal diet alone (NC), 2) positive control receiving basal diet plus 50 mg/kg of chlortetracycline (CTC), 3) basal diet plus 150 mg/kg COEC (COEC150), 4) plus 300 mg/kg COEC (COEC300), and 5) plus 450 mg/kg COEC (COEC450). The supplement trial was continued for 42 d. The results showed that CTC, COEC300, and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli (E. coli) in the cecal digesta at 21 d was lower in the CTC, COEC300, and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the E. coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450 mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses, and inhibit the proliferation of cecal pathogenic bacteria.

Contribution of mitochondria to postmortem muscle tenderization: a review

Postmortem meat tenderization is a process mediated by a series of biochemical reactions related to muscle cell death. Cell death is considered a sign that muscle has started to transform into meat. Mitochondria play a significant role in regulating and executing cell death, as they are an aggregation point for many cell death signals and are also the primary target organelle damaged by tissue anoxia. Mitochondrial damage is likely to have an expanded role in postmortem meat tenderization. This review presents current findings on mitochondrial damage induced by the accumulation of reactive oxygen species during postmortem anaerobic metabolism and on the impact of mitochondrial damage on proteolysis and discusses how this leads to improved tenderness during aging. The underlying mechanisms of mitochondrial regulation of postmortem muscle tenderization likely focus on the mitochondria's role in postmortem cell death and energy metabolism. The death process of postmortem skeletal muscle cells may exhibit multiple types, possibly involving transformation from autophagy to apoptosis and, ultimately, necroptosis or necrosis. Mitochondrial characteristics, especially membrane integrity and ATP-related compound levels, are closely related to the transformation of multiple types of dead postmortem muscle cells. Finally, a possible biochemical regulatory network in postmortem muscle tenderization is proposed.

Efficacy of Dietary Supplementation with Zinc-Chromium Mixture, Organic Selenium, or Their Combinations on Growth Performance, Carcass Traits, and Blood Profiles of Broilers under Heat Stress Conditions

To determine the effects of organic selenium (0.0-0.6 mg and 0.9 mg Se/Kg diet) and Zn-Cr mixture (100 mg Zn/Kg diet plus 1.5 mg Cr/Kg diet) on broiler chicken performance, carcass traits, blood hematology, and biochemistry under heat stress conditions, this study was conducted. Under temperatures between 30.21 to 31.82 °C, 240 broiler chickens (Ross-308), which were 7-day-old, were randomly assigned to one of six treatments: T1 (control), T2 (100 mg Zn per kg of diet and 1.5 mg Cr per kg of diet), T3 (0.6 mg Se per kg of diet), T4 (0.9 mg Se per kg of diet), T5 (100 mg Zn, 1.5 mg Cr and (LSe), and T6 (100 mg Zn, 1.5 mg Cr and (HSe)). At 35 days old, the chicks fed a diet containing Zn-Cr with low or high organic selenium (organic-Se) outweighed the control group in terms of live body weight, weight gain, and feed conversion ratio (p < 0.05). In comparison to the control treatment, birds fed diets supplemented with Zn-Cr or organic-Se (LSe, HSe) significantly increased their serum levels of total protein and total antioxidant capacity. However, these additives resulted in a decrease (p < 0.01) in their serum levels of triglycerides, total cholesterol, low-density lipoprotein (LDL) cholesterol, creatinine, and uric acid. Together, it was found that trace elements (Zn-Cr and organic-Se) may greatly lessen the impacts of heat stress on broilers by promoting growth performance and boosting metabolic processes.

Effects of heat stress on the chemical composition, oxidative stability, muscle metabolism, and meat quality of Nile tilapia (Oreochromis niloticus)

The present study investigated the effects of chronic heat stress (HS) on the chemical composition, oxidative stability, muscle metabolism, and meat quality of Nile tilapia (Oreochromis niloticus). Compared with the control (26 °C), chronic HS (32 °C) lowered growth performance, the contents of whole-body lipid, muscle protein, and muscle lipid. Also, HS significantly increased the contents of reactive oxygen species (ROS) and decreased antioxidative status, causing a decline in meat quality, including increased lipid and protein oxidation, the centrifugal water loss, and cooking loss as well as decreased the fragmentation index and pH at 24 h, which may be attributed to induced apoptosis by excessive ROS in Nile tilapia meat. Moreover, metabolomic analysis showed HS lowered flavor and nutritional value by affecting amino acid, lipid, and nucleotide metabolism. These results reveal that HS adversely affects oxidative stability, meat quality, flavor, and nutrition, warranting its recognition and prevention.

Insight on the meat quality and carbonylation profile of breast muscle of broilers in response to chronic heat stress: A proteomic research

This study was conducted to explore the influences of carbonyl modification on proteins within the breast muscle of heat-stressed broilers and their correlations to decreased meat quality. The results showed that birds that suffered from heat stress had higher lightness, drip loss, shear force value, and hardness, and lower redness and springiness of breast meat than those under normal control and pair fed treatments. Proteomic analysis identified a total of 921 differentially carbonylated sites, which were allocated to 419 proteins. The modified sites included Lys, Pro, Arg, Trp, Cys, His, and Met. Seven motif sequences were detected, where five motifs neighbored Lys and two neighbored Pro. The differentially carbonylated proteins in heat-stressed birds mainly participated in the glycolytic process, collagen fibril organization, calcium homeostasis, and apoptosis. This study provided a unique landscape of the muscular carbonyl modification rule and unraveled the potential impact of carbonylated protein on meat quality.

Improving animal welfare status and meat quality through assessment of stress biomarkers: A critical review

Stress induces various physiological and biochemical alterations in the animal body, which are used to assess the stress status of animals. Blood profiles, serum hormones, enzymes, and physiological conditions such as body temperature, heart, and breathing rate of animals are the most commonly used stress biomarkers in the livestock sector. Previous exposure, genetics, stress adaptation, intensity, duration, and rearing practices result in wide intra- and inter-animal variations in the expression of various stress biomarkers. The use of meat proteomics by adequately analyzing the expression of various muscle proteins such as heat shock proteins (HSPs), acute phase proteins (APPs), texture, and tenderness biomarkers help predict meat quality and stress in animals before slaughter. Thus, there is a need to identify non-invasive, rapid, and accurate stress biomarkers that can objectively assess stress in animals. The present manuscript critically reviews various aspects of stress biomarkers in animals and their application in mitigating preslaughter stress in meat production.

Dietary curcumin supplementation relieves hydrogen peroxide-induced testicular injury by antioxidant and anti-apoptotic effects in roosters

This study was aimed to investigate the effects of dietary curcumin supplementation on the hydrogen peroxide (H₂O₂)-induced testicular oxidative damage in breeder roosters. Thirty-two 20-week roosters were randomly divided into four groups: (1) basal diet (CON); (2) basal diet with H₂O₂ challenge (H₂O₂); (3) basal diet with 200 mg/kg curcumin (CUR); (4) basal diet with 200 mg/kg curcumin and H₂O₂ challenge (CUR + H₂O₂). The trial lasted for 8 weeks, H₂O₂ challenged groups got an intraperitoneal injection of H₂O₂ at the 50 and 53 days, while the CON and CUR groups received an injection of saline. The results showed that dietary curcumin supplementation significantly decreased abnormal sperm rates in the semen, notably improved seminiferous tubules, increased testis scores, and serum testosterone levels. Curcumin supplementation could also ameliorate the redox damage caused by H₂O₂, by enhancing the capacities of antioxidant enzymes (CAT, GSH-Px, SOD, and T-AOC), and reducing MDA levels. In addition, curcumin normalized the H₂O₂-induced negative effects, which included downregulations in spermatogenesis-related genes (STAR, HSD3-β1, SYCP3, AKT1) and antioxidant genes (HMOX-1, NQO-1), reduced protein expressions of Nrf2, PCNA, and Bcl-2, and increased protein expressions of Caspase 3 and Bax. Moreover, H₂O₂-induced decreased mRNA expressions of EIF2AK3, Caspase3, and BCL-2 were all reversed by dietary curcumin supplementation. In summary, dietary curcumin supplementation could relieve H₂O₂-induced oxidative damage and reproduction decline through the Nrf2 signaling pathway and anti-apoptotic effects in roosters.

Reactive oxygen species-mediated oxidative stress accelerates glycolysis via activation of the CaMKKβ/AMPK pathway in the yak longissimus dorsi postmortem

BACKGROUND

Adenosine monophosphate-activated protein kinase (AMPK) is instrumental in the initiation of early postmortem glycolysis and the advent of pale, soft, and exudative (PSE) meat when cellular energy is altered. However, conflicting studies show that AMPK activation without corresponding energy level changes in PSE meat challenges this long-held notion. Here, we examined the effects of reactive oxygen species (ROS)-mediated oxidative stress on AMPK activation in the context of glycolysis, protein solubility, and water-holding capacity (WHC) in the postmortem yak longissimus dorsi (LD) muscle. Further, we explored the mechanisms underlying these effects.

RESULTS

Hydrogen peroxide (H₂ O₂ ) significantly augmented the degree of oxidative stress, increasing the production of ROS and malondialdehyde excessive production and reducing the activity of the anti-oxidants superoxide dismutase and glutathione peroxidase. In turn, oxidative stress dramatically promoted AMPK activation and glycolysis by increasing glycogen depletion and promoting hexokinase and phosphofructokinase activity. Subsequently, lactic acid accumulation increased, leading to a rapid decline in pH, which aggravated protein solubility degree and centrifugal loss in the early postmortem yak LD muscle. Importantly, these changes caused by oxidative stress were eliminated by the AMPK inhibitor. Mechanistically, oxidative stress elevated calcium ion (Ca²⁺ ) levels, which mobilized calcium/calmodulin-dependent protein kinase β (CaMKKβ) and AMPK. Rescue experiments confirmed that the increases were attenuated using Ca²⁺ and CaMKKβ chelators, respectively.

CONCLUSION

These results indicated that oxidative stress caused by ROS hastened early-stage postmortem glycolysis and reduced the WHC of yak meat. These effects were likely mediated by the alternative and energy-independent CaMKKβ/AMPK signaling pathway. © 2022 Society of Chemical Industry.

Protective Effect of Phloretin against Hydrogen Peroxide-Induced Oxidative Damage by Enhancing Autophagic Flux in DF-1 Cells

Phloretin (PHL) is a dihydrochalcone flavonoid isolated from the peel and root bark of apples, strawberries, and other plants with antioxidative characteristic. In this study, we aimed to investigate the protective effect and the potential mechanism of PHL on hydrogen peroxide (H₂O₂)-induced oxidative damage in DF-1 cells. The results showed that PHL exhibited no cytotoxic effect on DF-1 cells at concentration below 20 μM. PHL markedly increased H₂O₂-reduced cell viability, decreased H₂O₂-induced apoptosis, as evidenced by reduced apoptosis rate, the upregulation of gene and protein level of Bcl-2, and the downregulation of gene and protein level of Bax and Cleaved caspase3. In addition, PHL reduced H₂O₂-induced reactive oxygen species (ROS) production and restored antioxidant enzymes activities as well as mitochondrial membrane potential in a dose-dependent manner. Moreover, PHL prior to H₂O₂ further increased LC3-II level, promoted p62 turnover and improved lysosomal function. Importantly, autophagy inhibitor chloroquine (CQ) reversed the protective effect of PHL, and increased H₂O₂-induced apoptosis. Furthermore, PHL inhibited the phosphorylation levels of ERK, p38, and JNK. Collectively, these results indicate that PHL could attenuate H₂O₂-induced oxidative injury and apoptosis by maintaining lysosomal function and promoting autophagic flux, and MAPKs pathway may be involved in this process. Our study provides evidence that PHL could as a new strategy to against oxidative damage in poultry industry.

H2O2-induced oxidative stress improves meat tenderness by accelerating glycolysis via hypoxia-inducible factor-1α signaling pathway in postmortem bovine muscle

Reactive oxygen species (ROS) affect meat quality through multiple biochemical pathways. To investigate the effect of ROS on postmortem glycolysis and tenderness of bovine muscle, ROS content, glycolytic potential, glycolysis rate-limiting enzyme activities, expression of hypoxia-inducible factor-1α (HIF-1α), phosphatidylinositol 3-kinase (PI3K), serine-threonine kinase (AKT), phosphorylated AKT (p-AKT), and tenderness were determined in the H2O2 group and control group. Results showed that the H2O2 group exhibited significantly higher ROS content within 48 h, coupled with increased glycolytic potential, pH decline, hexokinase (HK), and phosphofructokinase activities (PFK) early postmortem. These were attributed to ROS-induced PI3K/AKT signaling pathway activation and resultant HIF-1α accumulation. Moreover, shear force in the H2O2 group reached the peak 12 h earlier and decreased obviously after 24 h, accompanied by a significantly higher myofibril fragmentation index (MFI). These findings suggested that ROS drive HIF-1α accumulation by activating PI3K/AKT signaling pathway, thereby accelerating glycolysis and tenderization of postmortem bovine muscle.

Transcriptome analysis reveals the mechanism of chronic heat stress on meat quality of broilers

Background

Chronic heat stress has a negative impact on poultry meat quality. Although this has been extensively investigated, previous studies have primarily focused on metabolic alterations and oxidative stress in the pectoralis major (PM) muscle under chronic heat stress, and not all of the underlying molecular mechanisms are completely understood.

Methods

A total of 144 male Arbor Acres broilers (28 d old) were randomly allocated into 3 treatment groups: (1) the normal control (NC) group, with broilers raised at 22 °C and fed a basal diet; (2) the heat stress (HS) group, with birds raised at 32 °C and fed a basal diet; and (3) the pair-fed (PF) group, with birds raised at 22 °C and fed the amount of feed equal to the feed consumed on the previous day by the HS group. The experiment lasted for 14 d.

Results

Chronic heat stress decreased the average daily feed intake and average daily gain, increased feed:gain ratio (P < 0.05); and increased drip loss, cooking loss, shear force, hardness, and decreased pH, redness (a*); and springiness of PM muscle (P < 0.05). Furthermore, chronic heat stress decreased muscle fiber density, increased connective tissue, and led to intracellular vacuolation. The transcriptome analyses indicated that the effect of chronic heat stress on meat quality was not only related to metabolism and oxidative stress, but also to signal transduction, immune system, transport and catabolism, cell growth and death, and muscle structure.

Conclusions

Chronic heat stress has a negative impact on the growth performance, meat quality, and the PM muscle structure of broilers. Transcriptome analysis revealed a comprehensive understanding of the mechanism of the chronic heat stress-induced deterioration of broiler meat quality at the transcriptional level.

Integration of multi-omics data reveals cis-regulatory variants that are associated with phenotypic differentiation of eastern from western pigs

Background

The genetic mechanisms that underlie phenotypic differentiation in breeding animals have important implications in evolutionary biology and agriculture. However, the contribution of cis-regulatory variants to pig phenotypes is poorly understood. Therefore, our aim was to elucidate the molecular mechanisms by which non-coding variants cause phenotypic differences in pigs by combining evolutionary biology analyses and functional genomics.

Results

We obtained a high-resolution phased chromosome-scale reference genome with a contig N50 of 18.03 Mb for the Luchuan pig breed (a representative eastern breed) and profiled potential selective sweeps in eastern and western pigs by resequencing the genomes of 234 pigs. Multi-tissue transcriptome and chromatin accessibility analyses of these regions suggest that tissue-specific selection pressure is mediated by promoters and distal cis-regulatory elements. Promoter variants that are associated with increased expression of the lysozyme (LYZ) gene in the small intestine might enhance the immunity of the gastrointestinal tract and roughage tolerance in pigs. In skeletal muscle, an enhancer-modulating single-nucleotide polymorphism that is associated with up-regulation of the expression of the troponin C1, slow skeletal and cardiac type (TNNC1) gene might increase the proportion of slow muscle fibers and affect meat quality.

Conclusions

Our work sheds light on the molecular mechanisms by which non-coding variants shape phenotypic differences in pigs and provides valuable resources and novel perspectives to dissect the role of gene regulatory evolution in animal domestication and breeding.

Effects of dietary supplementation with selenium yeast and jujube powder on mitochondrial oxidative damage and apoptosis of chicken

The main objective of this study was to explore the effects of dietary selenium yeast and jujube powder on mitochondrial oxidative damage and cell apoptosis of broilers during postmortem aging, chicken breasts of broilers fed diets supplemented with different concentrations of selenium yeast and jujube powder were used as research subjects. With the prolongation of postmortem aging time, the levels of reactive oxygen species (ROS), carbonyl content, mitochondrial permeability transition pore (MPTP) openness, and mitochondrial membrane permeability increased significantly (P < 0.05). The contents of the sulfhydryl, mitochondrial membrane potential, shear force, and cytochrome C (Cyt-c) reduction level decreased significantly (P < 0.05). The activity of Caspase-3 and Caspase-9 increased from 0 to 24 h postmortem but fell from 24 to 72 h postmortem. Compared with the control group, dietary selenium yeast and jujube powder significantly reduced mitochondrial oxidative damage. They greatly increased the shear force, mitochondrial membrane potential, and Cyt-c reduction levels (P < 0.05). Among them, the combination group of high-dose selenium yeast and jujube powder had more significant effects on ROS scavenging, reducing cell membrane permeability, protecting cell membrane integrity, and increasing Cyt-c reduction level (P < 0.05). In conclusion, cell apoptosis intensifies during the chicken breast's aging time, and muscle tenderness continues. Still, different doses of dietary selenium yeast and jujube powder can inhibit mitochondrial oxidation to various degrees. The combined group of selenium yeast and jujube powder with 0.6 mg·kg⁻¹ has the best effect. This study is of great significance for applying natural antioxidant ingredients such as selenium yeast and jujube powder in the development and utilization of poultry feed.

Effects of faba bean (Vicia faba L.) on fillet quality of Yellow River carp (Cyprinus carpio) via the oxidative stress response

In order to further explain the fillet texture improvement of Yellow River carp (Cyprinus carpio) fed with faba bean (Vicia faba L.), a three-month rearing trial was conducted to investigate fatty acid composition, antioxidant capacity, myofiber development, collagen deposition and transcriptome in white muscle of two farmed carp groups (One was fed only faba bean, the other was fed commercial diet). As a strong oxidant, faba bean changed fatty acids composition in white muscle, especially DHA and EPA, up-regulated the levels of reactive oxygen species (ROS) and down-regulated major antioxidant enzyme activities in the hepatopancreas and white muscle. Through the analysis of transcriptome and subsequent verification analysis, we speculated that the increase of ROS led to the decrease of myofiber diameter and collagen metabolism. This study provides a theoretical basis for further understanding the regulation of faba bean on fillet texture characteristic of Yellow River carp.

Keratinase improves the growth performance, meat quality and redox status of broiler chickens fed a diet containing feather meal

The objective of this study was to assess the effects of dietary supplementation of keratinase on the production of broilers fed a diet containing feather meal. A total of 162 1-d-old Cobb 500 male broiler (n = 9 cages/diet with 6 chicks/cage) were randomly allocated to 3 dietary treatments. The broilers were fed a corn-soybean-feather meal based diet (BD), or BD supplemented with keratinase at 100,000 or 200,000 U/kg for 6 weeks. Compared to the control, dietary supplementation with 200,000 U/kg keratinase increased (P < 0.05) body weight gain (3.6–4.3%) and reduced feed conversion ratio (2.4–5.6%) during the various experimental periods, and also improved (P < 0.05) apparent total tract digestibility of ash and calcium by 45.0% and 8.8%, respectively. Meanwhile, dietary supplementation of keratinase at 100,000 U/kg reduced (P < 0.05) the drip loss (29.2%), while 200,000 U/kg keratinase supplementation increased (P < 0.05) the pH value (1.6%) at 45 min and decreased (P < 0.05) the lightness (L* value; 13.6%) and drip loss (22.1%) of pectoral muscle. Moreover, dietary supplementation of keratinase at both levels of 100,000 and 200,000 U/kg increased (P < 0.05) Glutathione peroxidase activity (82.5–87.5%) and decreased the Malondialdehyde concentration (14.5–18.3%) in the pectoral muscle. In conclusion, dietary supplementation of keratinase at 200,000 U/kg can improve the performance, meat quality, apparent total tract digestibility of nutrients, and redox status of broiler chickens fed a diet containing feather meal.

Potential Implications of Natural Antioxidants of Plant Origin on Oxidative Stability of Chicken Albumen during Storage: A Review

Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling, viscosity, and elasticity attributes are retained. Improved albumen quality is of benefit to consumers and to the food and health industries. Egg quality often declines during storage because eggs are highly perishable products and are most often not consumed immediately after oviposition. This review provides insights into albumen quality in terms of changes in albumen structure during storage, the influence of storage time and temperature, and the mitigation effects of natural dietary antioxidants of plant origin. During storage, albumen undergoes various physiochemical changes: loss of moisture and gaseous products through the shell pores and breakdown of carbonic acid, which induces albumen pH increases. High albumen pH acts as a catalyst for structural changes in albumen, including degradation of the β-ovomucin subunit and O-glycosidic bonds, collapse of the ovomucin-lysozyme complex, and decline in albumen protein–protein interactions. These culminate in declined albumen quality, characterized by the loss of albumen proteins, such as ovomucin, destabilized foaming and gelling capacity, decreased antimicrobial activity, albumen liquefaction, and reduced viscosity and elasticity. These changes and rates of albumen decline are more conspicuous at ambient temperature compared to low temperatures. Thus, albumen of poor quality due to the loss of functional and biological properties cannot be harnessed as a functional food, as an ingredient in food processing industries, and for its active compounds for drug creation in the health industry. The use of refrigerators, coatings, and thermal and non-thermal treatments to preserve albumen quality during storage are limited by huge financial costs, the skilled operations required, environmental pollution, and residue and toxicity effects. Nutritional interventions, including supplementation with natural antioxidants of plant origin in the diets of laying hens, have a promising potential as natural shelf-life extenders. Since they are safe, without residue effects, the bioactive compounds could be transferred to the egg. Natural antioxidants of plant origin have been found to increase albumen radical scavenging activity, increase the total antioxidant capacity of albumen, reduce the protein carbonyl and malondialdehyde (MDA) content of albumen, and prevent oxidative damage to the magnum, thereby eliminating the transfer of toxins to the egg. These products are targeted towards attenuating oxidative species and inhibiting or slowing down the rates of lipid and protein peroxidation, thereby enhancing egg quality and extending the shelf life of albumen.

Protective effects of chlorogenic acid on the meat quality of oxidatively stressed broilers revealed by integrated metabolomics and antioxidant analysis

Oxidation is a major cause of meat quality deterioration during broiler production, which leads to undesirable meat color and impaired water holding capacity (WHC), thereby impacting consumer appeal and satisfaction. Chlorogenic acid (CGA), a natural phenolic acid, is regarded as a potential, safer and healthier antioxidant to improve meat quality. To investigate the protective effects of CGA on the meat quality of oxidatively stressed broilers, 240 one-day-old male Cobb broiler chickens were allocated to four treatments: basal diet (control group), basal diet + dexamethasone (DEX) injection (DEX group), basal diet containing 500 mg kg^-1 CGA (CGA group), and basal diet containing 500 mg kg^-1 CGA + DEX injection (DEX_CGA group). Meat quality, antioxidant capacity, the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, and metabolomic profile were detected in the breast muscle of broilers. Then, correlation analysis between meat quality and antioxidant capacity, antioxidant-related genes, and metabolites was performed. The results indicated that CGA supplementation improved the growth performance and meat quality traits (pH, WHC, and meat color) and enhanced the antioxidant enzyme activity by activating the Nrf2 pathway in the breast muscle of oxidatively stressed broilers. A total of 619 metabolites were identified, among which 93 differential metabolites were found between control and DEX groups, and 65 differential metabolites were observed between DEX and DEX_CGA groups. Breast metabolic profiles were changed by DEX treatment, while CGA supplementation could normalize the metabolic changes in DEX-challenged broilers. Metabolic pathway analysis revealed that most of the differential metabolites between DEX and DEX_CGA groups were involved in pyrimidine/purine, propanoate and phenylalanine metabolism, primary bile acid biosynthesis, and lysine metabolism, which may contribute to explain the protective effects of CGA on meat quality. Moreover, according to the correlation analysis, four metabolites were identified as potential biomarkers to predict the meat quality. In conclusion, our findings demonstrate that CGA is an effective, natural and safe antioxidant to enhance the quality of meat from intensive industrial poultry production.

Housekeeping Proteins in Meat Quality Research: Are They Reliable Markers for Internal Controls in Western Blot? A Mini Review

Advancements in technology and analytical methods enable researchers to explore the biochemical events that cause variation in meat quality. Among those, western blot techniques have been successfully used in identifying and quantifying the key proteins that have critical functions in the development of meat quality. Housekeeping proteins, like β-actin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and tubulins are often used as internal controls in western blots to normalize the abundance of the protein of interest. However, there are increasing concerns about using housekeeping proteins for western blot normalization, as these proteins do not demonstrate any loading differences above the relatively small total protein loading amounts of 10μg. In addition, the interaction between these housekeeping proteins and programmed cell death processes highlights the concerns about using the housekeeping protein as the internal control in meat quality research. Moreover, recent proteomic research has indicated that the abundance of some housekeeping proteins, like β-actin, GAPDH, and tubulin, can be altered by preslaughter stress, dietary supplementation, sex, slaughter method, genotype, breed, aging period, muscle type, and muscle portion. Furthermore, these housekeeping proteins could have differential expression in meat with differing color stability, tenderness, and water holding capacity. Therefore, this review aims to examine the realities of using housekeeping proteins as the loading control in meat quality research and introduce some alternative methods that can be used for western blot normalization.

Effects of quercetin on tenderness, apoptotic and autophagy signalling in chickens during post-mortem ageing

The effect of quercetin on chicken breast muscle tenderness and the associated mechanism were investigated. The results indicated that quercetin significantly decreased the shear force and increased the myofibril fragmentation index (MFI). Haematoxylin-eosin-stained images showed that the internal structure of myofibril bundles in the quercetin-treated group was obviously degraded. Transmission electron microscopy showed that the myofibril structure, especially the M-line and A-band, was seriously degraded after quercetin treatment. Furthermore, quercetin treatment increased caspase-3 activity and the Bax/Bcl-2 ratio. The intensity of BiP, XBP1 and p-IRE1/IRE1 ratio increased significantly, and caspase-12 was activated. In addition, quercetin induced the transition from LC3I to LC3II and increased the expression of ATG7 and Beclin-1. The PI3K/Akt/mTOR signalling pathway was involved in the induction of autophagy and apoptosis by quercetin. These results indicated quercetin can promote meat tenderization, and activate apoptosis and autophagy pathways during post-mortem ageing.

H2O2-induced oxidative stress impairs meat quality by inducing apoptosis and autophagy via ROS/NF-κB signaling pathway in broiler thigh muscle

Oxidative stress is the downstream of various adverse stresses which impairs meat quality of broiler chickens. Yet, the specific molecular mechanisms of oxidative stress in meat quality of broiler thigh muscle remains unclear. This study investigated the effects and mechanisms of H₂O₂-induced oxidative stress on meat quality of broiler thigh muscle, with particular emphasis on apoptosis and autophagy and the ROS/NF-κB signaling pathway. The results showed that 10%H₂O₂-treated broilers exhibited significantly higher drip loss and shear force and lower pH_24h and muscle weight. Moreover, the ROS formation, the contents of oxidation products, the expressions of caspases (3, 6, 8, 9), Beclin1, and LC3-II/LC3-I were significantly increased, whereas the levels of antioxidation products and the expression of phosphorylation of NF-κBp65 were significantly decreased. These findings from the present study indicating that H₂O₂-induced oxidative stress significantly impaired the meat quality by inducing apoptosis and abnormal autophagy via ROS/NF-κB signaling pathway in the broiler thigh muscle.

Intervention of NF-Κb Signaling Pathway and Preventing Post-Operative Cognitive Dysfunction as Well as Neuronal Apoptosis

Background:

The Postoperative cognitive dysfunction (POCD) model was constructed by resection of the left hepatic lobe in aged mice to determine the behavioral effects of the POCD model in aged mice and the relationship between NF-κB and POCD in apoptosis and autophagy. Provide a theoretical basis for POCD prevention and treatment.

Methods:

This study was carried out in Ningbo No. 6 Hospital, Zhejiang, China, from Jun 2019 to Dec 2020. The POCD model was constructed after resection of the left extrahepatic lobe in aged mice and randomly divided into 6 groups: sham operation group, operation group (normal saline control group, solvent group, YC-1 group, PDTC group and 3-MA group). Related indicators of behavioral changes, neuronal inflammatory responses, apoptosis, and autophagy were examined.

Results:

The escape latency of the aged mice in the surgical group was significantly prolonged at three time points compared with the control group, and the number of insertions decreased significantly. Microglia are activated and the inflammatory response is increased, whereas PDTC has an inhibitory effect. It was demonstrated that apoptosis and necrosis of neurons can be induced by the NF-κb pathway, and autophagy can be promoted, whereas autophagy occurs before apoptosis.

Conclusion:

Activation of NF-κb pathway in neurons after POCD causes neuronal apoptosis and autophagy, and cognitive impairment occurs. PDTC, a NF-κb pathway inhibitor, can effectively reduce neuronal apoptosis induced by secondary brain injury after POCD. Necrosis, to protect the brain tissue.

An underlying softening mechanism in pale, soft and exudative - Like rabbit meat: The role of reactive oxygen species - Generating systems

This work investigated the role of reactive oxygen species (ROS) - generating systems on the softening of the pale, soft and exudative-like (PSE-like) rabbit meat during aging. PSE-like meat was induced by incubation of post-mortem rabbit Longissimus thoracis et lumborum at 37 °C for 3 h. During aging, PSE-like meat samples had higher values in peroxides value, thiobarbituric acid-reactive substances, metmyoglobin percentage, ferrylmyoglobin content, non-heme iron content, hydroxyl radical content and ROS concentration compared with the normal ones, suggesting that PSE-like incubation could activate lipid-oxidizing system, myoglobin-mediated oxidation system, together with metal-catalyzed oxidation system. Additionally, higher protein carbonyl content was observed in PSE-like meat, along with a significant loss in sulfhydryl group. The results of SDS-PAGE suggested that more serious protein degradation occurred in PSE-like meat. It is plausible that the activated ROS-generating system played an underlying role in the softening texture during the aging period of PSE-like meat.

Age-specific effect on endogenous oxidative and antioxidative characteristics of longissimus thoracis muscle of yak during early postmortem period

Effects of age on postmortem redox states were investigated in yak muscles. Extended postmortem time reduced the muscle antioxidant capacity and induced oxidation in lipids, myoglobin, and proteins. Compared with older yaks, muscles of younger ones could delay this oxidation process due to lower initial myoglobin content of 30.7%, lipid peroxidation of 42.4%, H₂O₂ of 41.2%, and intramuscular fat of 65.6% (of 3.66 times higher PUFAs). They also possessed greater antioxidase content/activity, such as phospholipase A2 content of 30.7% and glutathione reductase activity of 50.6%. Muscles exhibited age-specific overall antioxidative characteristics during 72 h postmortem and gradually formed overall oxidative ones after 72 h postmortem with an initial similarity between 2- and 4-year (or 6- and 12-year) on canonical discriminant analyses. The formation of age-specific overall oxidative characteristics can be attributable to the antioxidative specificity of age on canonical correlation analyses. Age-specific redox characteristics required differentiated preference in meat processing and preservation.

Dietary Selenized Glucose Increases Selenium Concentration and Antioxidant Capacity of the Liver, Oviduct, and Spleen in Laying Hens

Selenized glucose (SeGlu) is a new type of organic selenium (Se) that is synthesized through the selenide reaction of glucose with sodium hydrogen selenide. This study aimed to clarify the influence of dietary SeGlu on the Se level and antioxidant capacity of the liver, oviduct, and spleen in laying hens. A total of 360, 60-week-old, Hy-Line Brown laying hens were randomly assigned to three treatment groups: a basal diet alone (control group, without adding exogenous Se) or the basal diet supplemented with 0.3 mg/kg of Se from sodium selenite (SS) or 5 mg/kg of Se from SeGlu. Diets with SeGlu increased Se levels in the liver, oviduct, and spleen of laying hens (P < 0.001). Compared with the control and SS groups, diet supplemented with SeGlu enhanced glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (T-AOC) in the spleen and oviduct as well as the scavenging ability of 2, 2-diphenyl-1-picrylhydrazyl free radical (DPPH•) in the oviduct (P < 0.05). Compared with the control group, SeGlu treatment resulted in an increase (P < 0.05) in GSH-Px activity, T-AOC, and scavenging abilities of hydroxyl radical and DPPH• in the liver of hens. In addition, dietary SeGlu and SS decreased the hydrogen peroxide level in the oviduct in comparison to the control group (P < 0.05). Therefore, dietary SeGlu increased Se concentration and antioxidant ability in the liver, oviduct, and spleen of laying hens. Moreover, SeGlu may be used as a potential source of Se additive in laying hen production.

Investigating the growth performance, meat quality, immune function and proteomic profiles of plasmal exosomes in Lactobacillus plantarum-treated broilers with immunological stress

Exosomes are extracellular membranous nanovesicles that carry functional molecules to mediate cell-to-cell communication. To date, whether probiotics improve the immune function of broilers by plasmal exosome cargo is unclear. In this study, 300 broilers were allocated to three treatments: control diet (CON group), control diet + dexamethasone injection (DEX group), and control diet containing 1 × 10⁸ cfu g^-1 P8 + DEX injection (P8 + DEX group). The growth performance, meat quality and immune function of plasma and jejunal mucosa were detected. Exosomes were isolated from the plasma and characterized. Then, the exosome protein profile was determined by proteomic analysis. Correlation analyses between the exosomal proteins and growth performance, meat quality, immune function were performed. Lastly, the related protein levels were verified by multiple reaction monitoring (MRM). Results showed that P8 treatment increased the growth performance, meat quality and immune function of DEX-induced broilers with immunological stress. Moreover, the average diameters, cup-shaped morphology and expressed exosomal proteins confirmed that the isolated extracellular vesicles were exosomes. A total of 784 proteins were identified in the exosomes; among which, 126 differentially expressed proteins (DEPs) were found between the DEX and CON groups and 102 DEPs were found between the P8 + DEX and DEX groups. Gene ontology analysis indicated that DEPs between the DEX and CON groups are mainly involved in the metabolic process, cellular anatomical entity, cytoplasm, etc. DEPs between the P8 + DEX and DEX groups are mainly involved in the multicellular organismal process, response to stimulus, cytoplasm, etc. Pathway analysis revealed that most of the DEPs between the DEX and CON groups participated in the ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton, etc. Most of the DEPs between the P8 + DEX and DEX groups participated in the ErbB and PPAR signaling pathways. Moreover, many DEPs were correlated with the altered parameters of growth performance, meat quality and immunity in P8-treated broilers. MRM further revealed that the upregulated FABP6 and EPCAM in the DEX group were decreased by P8 + DEX treatment, and the downregulated C1QTNF3 in the DEX group was increased by P8 + DEX treatment. In conclusion, our findings demonstrated that P8 may promote the immune function, growth performance and meat quality of broilers with immunological stress by regulating the plasma exosomal proteins, especially the proteins of FABP6, EPCAM and C1QTNF3 and the pathway of PPAR (ILK/FABP6).

Probing the effects of dietary selenised glucose on the selenium concentration, quality, and antioxidant activity of eggs and production performances of laying hens

Selenised glucose (SeGlu) is a newly invented organic selenium compound being synthesised through the selenisation reaction of glucose with NaHSe. We hypothesised that glucose could be used as a carrier for the stable low-valent organoselenium to enhance the selenium concentrations of eggs. To probe the effects of SeGlu on production performances of laying hens, egg selenium concentration, egg quality, and antioxidant indexes, 360 Hy-Line Brown laying hens were randomly assigned to three treatment groups fed with a basal diet alone or the diet supplemented with 5 or 10 mg/kg of Se from SeGlu. The results showed that SeGlu treatment not only enhanced (P < 0.001) the Se concentration in albumen and yolks, glutathione peroxidase activity, and total antioxidant capacity of eggs but also increased (P = 0.032) the Haugh unit of eggs being stored for 2 weeks, while the production performances and egg qualities of fresh eggs were not affected. Moreover, SeGlu supplementation linearly (P < 0.001) increased the scavenging ability of superoxide radicals in eggs. Briefly, SeGlu can enhance the selenium deposition and antioxidant activity of eggs, thereby meeting the nutritional requirement for Se-deficient humans.

Effect of supplementing hydroxy selenomethionine on meat quality of yellow feather broiler

This study was conducted to evaluate the effect of supplementing hydroxy selenomethionine (OH-SeMet) on performance, selenium (Se) deposition in the breast muscle, quality and oxidative stability, and expression of selenoprotein encoding genes of breast meat of the native slow-growing yellow-feathered broiler birds. A total of 375 one-day-old local yellow male birds were randomly assigned into 5 dietary treatments, supplemented with Se 0.0, 0.2, 0.4, 0.6, and 0.8 mg/kg in the form of OH-SeMet. Each treatment consisted of 5 replicates and each replicate had 15 birds, the birds were fed on basal diet containing corn and soybean meal, and the experiment lasted for 63 d. The results showed that dietary Se supplementation linearly increased (P < 0.001) Se contents in both serum and muscle, no significant changes (P > 0.05) were observed on growth performance, yield of breast, meat color, and intramuscular fat deposition of the breast muscle. Dietary Se addition improved water-holding capacity, the pH_24h value, and tenderness of breast muscle, evidenced by a linear decreases of shear force (P < 0.05), accompanied by lower thiobarbituric acid reactive substances and higher glutathione reductase activity. The mRNA abundance of selenoprotein encoding genes also responded to dietary Se levels. It is concluded that, dietary supplementation with OH-SeMet improved muscular Se deposition and meat quality of the native yellow birds, with enhanced antioxidant capability and regulation in selenogenome.

Autophagy in farm animals: current knowledge and future challenges

Autophagy (a process of cellular self-eating) is a conserved cellular degradative process that plays important roles in maintaining homeostasis and preventing nutritional, metabolic, and infection-mediated stresses. Surprisingly, little attention has been paid to the role of this cellular function in species of agronomical interest, and the details of how autophagy functions in the development of phenotypes of agricultural interest remain largely unexplored. Here, we first provide a brief description of the main mechanisms involved in autophagy, then review our current knowledge regarding autophagy in species of agronomical interest, with particular attention to physiological functions supporting livestock animal production, and finally assess the potential of translating the acquired knowledge to improve animal development, growth and health in the context of growing social, economic and environmental challenges for agriculture.Abbreviations: AKT: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ASC: adipose-derived stem cells; ATG: autophagy-related; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; BVDV: bovine viral diarrhea virus; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CMA: chaperone-mediated autophagy; CTSB: cathepsin B; CTSD: cathepsin D; DAP: Death-Associated Protein; ER: endoplasmic reticulum; GFP: green fluorescent protein; Gln: Glutamine; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; IF: immunofluorescence; IVP: in vitro produced; LAMP2A: lysosomal associated membrane protein 2A; LMS: lysosomal membrane stability; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MDBK: Madin-Darby bovine kidney; MSC: mesenchymal stem cells; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NBR1: NBR1 autophagy cargo receptor; NDV: Newcastle disease virus; NECTIN4: nectin cell adhesion molecule 4; NOD1: nucleotide-binding oligomerization domain 1; OCD: osteochondritis dissecans; OEC: oviduct epithelial cells; OPTN: optineurin; PI3K: phosphoinositide-3-kinase; PPRV: peste des petits ruminants virus; RHDV: rabbit hemorrhagic disease virus; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy.

Dietary taurine attenuates hydrogen peroxide-impaired growth performance and meat quality of broilers via modulating redox status and cell death signaling

Oxidative stress seriously affects poultry production. Nutritional manipulations have been effectively used to alleviate the negative effects caused by oxidative stress. This study investigated the attenuating effects and potential mechanisms of dietary taurine on the growth performance and meat quality of broiler chickens challenged with hydrogen peroxide (H2O2). Briefly, a total of 192 male Arbor Acres broilers (28 d old) were randomly categorized into three groups: non-injection of birds on basal diets (control), 10.0% H2O2 injection of birds on basal diets (H2O2), and 10.0% H2O2 injection of birds on basal diets supplemented with 5 g/kg taurine (H2O2 + taurine). Each group consisted of eight cages of eight birds per cage. Results indicated that H2O2 administration significantly reduced growth performance and impaired breast meat quality by decreasing ultimate pH and increasing shear force value (P < 0.05). Dietary taurine improved the body weight gain and feed intake and decreased feed/gain ratio of H2O2-challenged broilers. Meanwhile, oxidative stress induced by intraperitoneal injection of H2O2 suppressed the nuclear factor-κB (NF-κB) signaling and initiated autophagy and apoptosis. Compared with the H2O2 group, taurine supplementation restored the redox status in the breast muscle by decreasing levels of reactive oxygen species and contents of oxidative products and increasing antioxidant capacity (P < 0.05). Moreover, upregulated mRNA expression of NF-κB signaling-related genes, including NF-κB subunit 1 (p50) and B-cell CLL/lymphoma 2 (Bcl-2), and enhanced protein expression of NF-κB were observed in the H2O2 + taurine group (P < 0.05). Additionally, dietary taurine decreased the expression of caspase family, beclin1, and microtubule-associated protein 1light chain 3 beta (LC3-II; P < 0.05), thereby rescuing autophagy and apoptosis in breast muscle induced by H2O2. Collectively, dietary supplementation with taurine effectively improves growth performance and breast meat quality of broilers challenged with H2O2, possibly by protecting against oxidative injury and modulating cell death signaling.

Redox Homeostasis in Poultry: Regulatory Roles of NF-κB

Redox biology is a very quickly developing area of modern biological sciences, and roles of redox homeostasis in health and disease have recently received tremendous attention. There are a range of redox pairs in the cells/tissues responsible for redox homeostasis maintenance/regulation. In general, all redox elements are interconnected and regulated by various means, including antioxidant and vitagene networks. The redox status is responsible for maintenance of cell signaling and cell stress adaptation. Physiological roles of redox homeostasis maintenance in avian species, including poultry, have received limited attention and are poorly characterized. However, for the last 5 years, this topic attracted much attention, and a range of publications covered some related aspects. In fact, transcription factor Nrf2 was shown to be a master regulator of antioxidant defenses via activation of various vitagenes and other protective molecules to maintain redox homeostasis in cells/tissues. It was shown that Nrf2 is closely related to another transcription factor, namely, NF-κB, responsible for control of inflammation; however, its roles in poultry have not yet been characterized. Therefore, the aim of this review is to describe a current view on NF-κB functioning in poultry with a specific emphasis to its nutritional modulation under various stress conditions. In particular, on the one hand, it has been shown that, in many stress conditions in poultry, NF-κB activation can lead to increased synthesis of proinflammatory cytokines leading to systemic inflammation. On the other hand, there are a range of nutrients/supplements that can downregulate NF-κB and decrease the negative consequences of stress-related disturbances in redox homeostasis. In general, vitagene-NF-κB interactions in relation to redox balance homeostasis, immunity, and gut health in poultry production await further research.

Prospect of early vascular tone and satellite cell modulations on white striping muscle myopathy

Polyphasic myodegeneration potentially causes severe physiological and metabolic disorders in the breast muscle of fast-growing broiler chickens. To date, the etiology of recent muscle myopathies, such as the white striping (WS) phenotype, is still unknown. White striping–affected breast meats compromise the water holding capacity and predispose muscle to poor vascular tone, leading to the deterioration of meat qualities. Herein, this review article provides insight on the complexities around chicken breast myopathies: (i) the etiologies of WS occurrence in chicken; (ii) the metabolic changes that occur in WS defect in pectoralis major; and (iii) the interactions between breast muscle physiology and vascular tone. It also addressed the effects of nutritional supplements on muscle myopathies on chicken breast meats. Moreover, the review explored breast muscle biology focusing on the early preparation of satellite and vascular cells in fast-growth chicken breeds. Transcriptomics and histological analyses revealed poor vascularity in breast muscle of fast growth chickens. Thus, we suggest in ovo feeding of nutrients promoting vascularization and satellite cells replenishment as a potential strategy to enhance endothelium-derived nitric oxide availability to promote vascularization in the pectoralis major muscle region.

Hydrogen peroxide-induced oxidative stress impairs redox status and damages aerobic metabolism of breast muscle in broilers

Oxidative stress has always been a hot topic in poultry science. However, studies concerning the effects of redox status and glucose metabolism induced by hydrogen peroxide (H₂O₂) in the breast muscle of broilers have been rarely reported. This study was aimed to evaluate the impact of intraperitoneal injection of H₂O₂ on oxidative damage and glycolysis metabolism of breast muscle in broilers. We also explored the activation of the nuclear factor erythroid 2–related factor 2 (Nrf2) signaling pathway to provide possible mechanism of the redox imbalance. Briefly, a total of 320 one-day-old Arbor Acres chicks were randomly divided into 5 treatments with 8 replicates of 8 birds each (noninjected control, 0.75% saline-injected, 2.5, 5.0, and 10.0% H₂O₂-injected treatments). Saline group was intraperitoneally injected with physiological saline (0.75%) and H₂O₂ groups received an intraperitoneal injection of H₂O_2. The dosage of the injection was 1.0 mL/kg BW. All birds in the saline and H₂O₂ groups were injected on days 16 and 37 of the experimental period. At 42 d of age, 40 birds (8 cages per group and one chicken per cage) were selected to be stunned electrically (50 V, alternating current, 400 Hz for 5 s each one), and then immediately slaughtered via exsanguination. The results showed that broilers in the H₂O₂ injection group linearly exhibited higher contents of reactive oxygen species, carbonyl and malondialdehyde, and lower total antioxidant capacity and glutathione peroxidase activities. With the content of H₂O₂ increased, the H₂O₂ groups linearly downregulated the mRNA expressions of GPX, CAT, HMOX1, NQO1, and Nrf2 and its downstream target genes. In addition, H₂O₂ increased serum activities of creatine kinase and lactate dehydrogenase. Meanwhile, in the pectoral muscle, the glycogen content was linearly decreased, and the lactate content was linearly increased in muscle of broilers injected with H₂O₂. In addition, the activities of glycolytic enzymes including pyruvate kinase, hexokinase, and lactate dehydrogenase were linearly increased after exposure to H₂O₂. In conclusion, H₂O₂ injection could impair antioxidant status and enhance anaerobic metabolism of breast muscle in broilers.

Proteomic and metabolomic basis for improved textural quality in crisp grass carp (Ctenopharyngodon idellus C.et V) fed with a natural dietary pro-oxidant

Reactive oxygen species (ROS) regulate metabolism and chemical composition of various tissues. To understand how ROS affect the textural quality of fish muscle, we performed a multi-omics analysis on an established crisp grass carp model fed with a natural pro-oxidant faba bean. ROS levels were systemically and significantly increased up to three-fold in crisp grass carp, improving the muscle texture. Lipid metabolism was significantly enhanced up to five-fold in muscle and liver possibly to compensate the impaired carbohydrate metabolism of these tissues, but this caused further local ROS production. Mitochondrial damage associated with autophagy was evident in crisp grass carp. Proteomics revealed that elevated ROS likely disturbed the actin-myosin interaction and collagen turnover inducing fragmentation of myofibrillar proteins, all of which could have positively impacted the textural quality. The systemic metabolic changes that lead to the partial collapse of redox regulation likely underlie the ROS-induced improvement of textural quality.