Role of phosphorylation on characteristics of glycogen phosphorylase in lamb with different glycolytic rates post-mortem

Quantitative Phosphoproteomics Analysis Reveals the Protective Mechanism of Chlorogenic Acid on Immunologically Stressed Broiler Meat Quality

Modern poultry production is stressful for the birds, and this stress is recognized as a major cause of inferior meat quality. Chlorogenic acid (CGA), a plant phenolic acid, has excellent antioxidant and anti-inflammatory properties. The antioxidant capacity and phosphoproteomics of immunologically stressed broiler breast muscle were assessed to elucidate the mechanism of the beneficial effects of CGA on meat quality. Dietary CGA decreased drip and cooking loss, postmortem pH and antioxidant capacity of breast muscle from stressed broilers, and increased MyHC-I mRNA levels. Quantitative phosphoproteomics revealed that CGA supplementation downregulated the phosphorylation of myofibrillar proteins, glycolytic enzymes, and endoplasmic reticulum proteins involved in homeostasis, which contributed to improving the meat quality of broilers. Moreover, 14 phosphorylation sites (e.g., P13538-Ser1236 and F1NN63-Ser117) in 13 phosphoproteins were identified as key regulators of processes related to broiler meat quality. Together, these findings provide novel regulatory targets and nutritional strategies for improving the stressed broiler meat quality.

Identification of Candidate Genes and Pathways Linked to the Temperament Trait in Sheep

Temperament can be defined as the emotional variability among animals of the same species in response to the same stimulus, grouping animals by their reactivity as nervous, intermediate, or calm. Our goal was to identify genomic regions with the temperament phenotype measured by the Isolation Box Test (IBT) by single-step genome-wide association studies (ssGWAS). The database consisted of 4317 animals with temperament records, and 1697 genotyped animals with 38,268 effective Single Nucleotide Polymorphism (SNP) after quality control. We identified three genomic regions that explained the greatest percentage of the genetic variance, resulting in 25 SNP associated with candidate genes on chromosomes 6, 10, and 21. A total of nine candidate genes are reported for the temperament trait, which is: PYGM, SYVN1, CAPN1, FADS1, SYT7, GRID2, GPRIN3, EEF1A1 and FRY, linked to the energetic activity of the organism, synaptic transmission, meat tenderness, and calcium associated activities. This is the first study to identify these genetic variants associated with temperament in sheep, which could be used as molecular markers in future behavioral research.

Comparison of muscle fiber characteristics and meat quality between newborn and adult Haimen goats

Goat meat is popular with consumers for its rich nutritional content. Muscle fiber characteristics have been shown to play a crucial role in determining the quantity and quality of meat. However, little is known about the temporal changes in muscle fiber characteristics and meat quality during growth in goats. In this study, muscle fiber type, fiber diameter, fiber cross-sectional area (CSA), glycolytic potential (GP), meat pH, and meat color were analyzed in the gastrocnemius (GAS), gluteus medius (GM), biceps brachii (BB), longissimus lumborum (LL) muscles from newborn (NHMG) and adult (AHMG) Haimen goats. The distribution of type I and type Π fiber in goats is not consistent across the four muscles and undergoes alterations with age. The diameter and CSA of the muscle fibers were similar among the four NHMG muscles. However, in AHMG, the LL muscle had the largest fiber in terms of both diameter and CSA, followed by BB, GM, and GAS muscles. Moreover, the CSA of type Π fibers was higher than that of type I fibers in both NHMG and AHMG. GP values ranged from 90 to 140 umol/g across the muscle and no significant differences were observed. AHMG had a higher pH level and a* value, but lower L* and b* values than NHMG. Overall, our findings enhance our understanding of the changes in muscle fiber type and meat quality during the growth in Haimen goats and provide a basis for future research on the development and transformation of muscle fibers in goats.

Validation of protein biological markers of lamb meat quality characteristics based on the different muscle types

This work investigated the ability of 8 potential biomarkers (phosphoglycerate kinase-1 (PGK1), pyruvate kinase-M2 (PKM2), phosphoglucomutase-1 (PGM1), β-enolase (ENO3, myosin-binding protein-C (MYBPC1), myosin regulatory light chain-2 (MYLPF), troponin C-1 (TNNC1) and troponin I-1 (TNNI1)) to characterize meat quality by analyzing their relative abundance and enzymatic activity. Two different meat quality groups (Quadriceps femoris (QF) and Longissimus thoracis (LT) muscles) were selected at 24 h postmortem from 100 lamb carcasses. The relative abundance of PKM2, PGK1, PGM1, ENO3, MYBPC1, MYLPF, and TNNI1 was significantly different between LT and QF muscle groups (P < 0.01). Moreover, PKM, PGK, PGM, and ENO activity in LT muscle group was significantly lower than that in QF muscle (P < 0.05). Suggesting that PKM2, PGK1, PGM1, ENO3, MYBPC1, MYLPF, and TNNI1 can be used as robust biomarkers of lamb meat quality, providing the reference for understanding the molecular mechanism of postmortem meat quality formation in future.

Phosphorylation and acetylation responses of glycolytic enzymes in meat to different chilling rates

The aim of this study was to investigate the effects of chilling rate on phosphorylation and acetylation levels of the glycolytic enzymes in meat, including glycogen phosphorylase, phosphofructokinase, aldolase (ALDOA), triose-phosphate isomerase (TPI1), phosphoglycerate kinase, lactate dehydrogenase (LDH). The samples were assigned into three groups: Control, Chilling 1 and Chilling 2, corresponding to the chilling rates of 4.8 °C/h, 23.0 °C/h and 25.1 °C/h respectively. The contents of glycogen and ATP were significantly higher in samples from the chilling groups. The activity and phosphorylation level of the six enzymes were higher in samples at the chilling rate of 25.1 °C/h, while the acetylation level of ALDOA, TPI1 and LDH were inhibited. In brief, glycolysis was delayed and the activity of glycolytic enzymes were maintained at higher level by the changes of phosphorylation and acetylation levels at the chilling rates of 23.0 °C/h and 25.1 °C/h, which may partly explain why very fast chilling improves meat quality.

The effect of postmortem pH decline rate on caspase-3 activation and tenderness of bovine skeletal muscle during aging

This study aimed to investigate the effect of postmortem pH decline rate on caspase-3 activity and bovine muscle tenderness during aging. Protein denaturation, reactive oxygen species (ROS) levels, mitochondrial apoptosis factors, and shear force were assessed in bovine muscles with different pH decline rates. The results showed that, compared with the slow group, the fast pH decline group had a 1.79% and 1.39% higher sarcoplasmic protein denaturation at 6 and 12 h, respectively (p < .05), and a significantly or extremely significantly higher ROS levels at 6-24 (p < .05, p < .01). Moreover, the fast group had a 14.05%, 22.39%,18.34%, and 25.28% of higher mitochondrial dysfunction at 6, 12, 24, and 72 h, respectively (p < .05); a 16.71%, 23.39%, 17.05%, and 26.61% of lower cytochrome c reduction levels at 6, 12, 24, and 120 h, respectively (p < .05); a significantly increased caspase-3 activity and proportion of apoptotic nuclei at 12-168 and 24-168 h, respectively (p < .05); and a 5.70%, 7.24%, 12.16%, 10.10% and 10.49% decreased shear force at 12, 24, 72,120, and 168 h, respectively (p < .05). These results demonstrated that the fast postmortem pH decline enhanced caspase-3 activation and bovine muscle tenderization by mitochondrial dysfunction-induced apoptosis during aging. PRACTICAL APPLICATIONS: Beef tenderness has long been one of the most important concerns for consumers and the meat industry. To date, the postmortem aging process has been an effective way to improve the tenderness of chilled beef. However, changes in many of the elements in a cattle's muscle after slaughter might actually determine the final tenderness of the meat. The present study suggested that the fast postmortem pH decline could promote the activation of caspase-3 and improve the tenderness of beef during aging. This finding can provide a basis for the meat processing industry to produce beef with high tenderness. In the future, beef tenderness could even be improved by adjusting the glycolytic rate and pH of muscle for a short time after slaughter.

The formation of key aroma compounds in roasted mutton during the traditional charcoal process

The formation of key aroma compounds in roasted mutton during the traditional charcoal process were investigated. The results indicated that the samples roasted for 0-15 min could be discriminated using a flash GC E-nose and GC-O-MS combined with multivariate data analysis. A total of 37 odorants were identified, among which 15 odorants were confirmed as key aroma compounds by aroma recombination experiments. Significant increases in key aroma compositions and concentrations in samples were observed during the roasting process, in which hexanal had the highest concentration. The odour activity values (OAVs) of 15 key aroma compounds were maintained at high levels in the samples after roasting for 10 min. The roasted mutton had typical aromas of meaty, fatty, roasty, grassy, and sweet odours. The multivariate linear modeling indicated that a lower specific heat capacity and lower water activity could contribute to the formation of aroma compounds of samples.