Muscle Hypertrophy Is Linked to Changes in the Oxidative and Proteolytic Systems during Early Tenderization of the Spanish Breed "Asturiana de los Valles"

For fresh meat consumers, eating satisfaction is of utmost importance and tenderness is one of the most important characteristics in this regard. Our study examined beef of different animal biotypes of the autochthonous breed "Asturiana de los Valles" (AV) to determine if early postmortem oxidative and proteolytic processes may influence the final tenderness of the product. This meat-specialized breed shows different biotypes depending on the frequency of a myostatin mutation "mh" that induces double-muscling or muscular hypertrophy (mh/mh, mh/+, +/+). Samples from the longissimus dorsi muscles of yearling bulls were analyzed during the first 24 h postmortem. Changes in the redox balance of muscle cells were significant in the first hours after slaughter; total antioxidant activity was higher in the mh/mh biotype and it followed the shortening of the sarcomeres, a key parameter in understanding meat tenderness. The two proteolytic systems studied (proteasome and lysosome) followed distinct patterns. Proteasome activity was higher in the (mh/+) biotype, which correlated with higher protein damage. Lysosome proteolysis was increased in the more tender biotypes (mh genotypes). Autophagic activation showed significant differences between the biotypes, with (mh/mh) showing more intense basal autophagy at the beginning of the postmortem period that decreased gradually (p < 0.001), while in the normal biotype (+/+), it was slightly delayed and then increased progressively (p < 0.001). These results suggest that this type of catalytic process and antioxidant activity could contribute to the earlier disintegration of the myofibers, particularly in the mh/mh biotypes, and influence the conversion of muscle into meat.

Role of the endoplasmic reticulum in the search for early biomarkers of meat quality

Defects in meat quality such as dark, firm and dry (DFD) beef have been related to high levels of oxidative stress that produce cellular alterations that may affect to the process of meat quality acquisition. Despite the important role of endoplasmic reticulum (ER) in the cellular response to oxidative stress, its function in the muscle-to-meat conversion process has not yet been studied. In this study, differences in muscular antioxidant defense and the unfolded protein response (UPR) of the ER in CONTROL (normal pH₂₄) and dark, firm, and dry (DFD, pH₂₄ ≥ 6.2) beef at 24 h post-mortem were analyzed to understand the changes in the muscle-to-meat conversion process related to meat quality defects. DFD meat showed poor quality, lower antioxidant activity (P < 0.05) and higher UPR activation (P < 0.05), which indicates higher oxidative stress what could partly explain the occurrence of meat quality defects. Therefore, the biomarkers of these cellular processes (IRE1α, ATF6α, and p-eIF2α) are putative biomarkers of meat quality.

New insights into the search of meat quality biomarkers assisted by Orbitrap Tribrid untargeted metabolite analysis and chemometrics

Metabolite profiles of normal and defective dry, firm and dark (DFD) meat extracts with known ultimate pH (pHu) values were determined by Orbitrap Tribrid ID-X untargeted analysis coupled to chemometrics. An intelligent MS³ AcquireX^TM workflow firstly approached the unambiguous characterization of detected features that were subsequently quantified by a complementary MS¹ study of biological replicates. Chemometric research revealed how threonylphenylalanine (overexpressed in normal meats) together to tetradecadienoyl- and hydroxydodecanoyl-carnitines (both overexpressed in DFD meats) appropriately grouped meat groups assayed. Robustness of such biomarkers was confirmed through a time-delayed study of a blind set of samples (unknown pHu) and evidenced limitations of pHu as an isolated parameter for accurate meat quality differentiation. Other acyl-carnitines also characterized DFD samples, suggesting interferences induced by pre-slaughter stress (PSS) on lipid catabolism that would explain accumulation of such intermediate metabolites. Results achieved can ease understanding of biochemical mechanisms underlying meat quality defects.

Use of Near-Infrared Spectroscopy to Discriminate DFD Beef and Predict Meat Quality Traits in Autochthonous Breeds

The potential of near-infrared reflectance spectroscopy (NIRS) to discriminate Normal and DFD (dark, firm, and dry) beef and predict quality traits in 129 Longissimus thoracis (LT) samples from three Spanish purebreeds, Asturiana de los Valles (AV; n = 50), Rubia Gallega (RG; n = 37), and Retinta (RE; n = 42) was assessed. The results obtained by partial least squares-discriminant analysis (PLS-DA) indicated successful discrimination between Normal and DFD samples of meat from AV and RG (with sensitivity over 93% for both and specificity of 100 and 72%, respectively), while RE and total sample sets showed poorer results. Soft independent modelling of class analogies (SIMCA) showed 100% sensitivity for DFD meat in total, AV, RG, and RE sample sets and over 90% specificity for AV, RG, and RE, while it was very low for the total sample set (19.8%). NIRS quantitative models by partial least squares regression (PLSR) allowed reliable prediction of color parameters (CIE L*, a*, b*, hue, chroma). Results from qualitative and quantitative assays are interesting in terms of early decision making in the meat production chain to avoid economic losses and food waste.

New Insights on the Impact of Cattle Handling on Post-Mortem Myofibrillar Muscle Proteome and Meat Tenderization

This study investigated the effect of different cattle management strategies at farm (Intensive vs. Extensive) and during transport and lairage (mixing vs. non-mixing with unfamiliar animals) on the myofibrillar subproteome of Longissimus thoracis et lumborum (LTL) muscle of "Asturiana de los Valles" yearling bulls. It further aimed to study the relationships with beef quality traits including pH, color, and tenderness evaluated by Warner-Bratzler shear force (WBSF). Thus, comparative proteomics of the myofibrillar fraction along meat maturation (from 2 h to 14 days post-mortem) and different quality traits were analyzed. A total of 23 protein fragments corresponding to 21 unique proteins showed significant differences among the treatments (p < 0.05) due to any of the factors considered (Farm, Transport and Lairage, and post-mortem time ageing). The proteins belong to several biological pathways including three structural proteins (MYBPC2, TNNT3, and MYL1) and one metabolic enzyme (ALDOA) that were affected by both Farm and Transport/Lairage factors. ACTA1, LDB3, and FHL2 were affected by Farm factors, while TNNI2 and MYLPF (structural proteins), PKM (metabolic enzyme), and HSPB1 (small Heat shock protein) were affected by Transport/Lairage factors. Several correlations were found between the changing proteins (PKM, ALDOA, TNNI2, TNNT3, ACTA1, MYL1, and CRYAB) and color and tenderness beef quality traits, indicating their importance in the determination of meat quality and their possible use as putative biomarkers.

Caspase activity in post mortem muscle and its relation to cattle handling practices

BACKGROUND

Animal handling practices are one of the factors majorly affecting animal metabolism prior to slaughter. This phenomenon increases the occurrence of meat quality defects such as dark cutting-beef, causing high economical losses in the meat industry. Under this framework, the assessment of apoptosis onset in post mortem muscle was proposed as a novel approach to reveal biochemical characteristics in several Spanish bovine breeds (Asturiana de los Valles, Retinta and Rubia Gallega) managed under different production systems (intensive versus semi-extensive) and transport/lairage conditions (mixing versus not mixing with unfamiliar animals). To do so, the activities of initiator caspase 9 and executioner caspases 3/7 were determined in Longissimus thoracis et lumborum muscle at three early post mortem times (2, 8, and 24 h).

RESULTS

Breed effect and transport/lairage conditions were the most relevant factors that influenced both caspase activities over post mortem time, showing Rubia Gallega breed a completely different behavior compared to Asturiana de los Valles and Retinta breeds. Moreover, it is postulated that apoptosis cascade is initiated via the activation of caspase 9 under hypoxic or metabolic stress followed by the activation of executioner caspases 3/7.

CONCLUSIONS

Assessment of apoptosis on post mortem muscle can be a novel approach to study the influence of animal handling on muscle metabolism and post mortem cell death and its consequences on meat quality traits. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessment of Stress by Serum Biomarkers in Calves and Their Relationship to Ultimate pH as an Indicator of Meat Quality

Simple Summary

The routine handling of cattle during the rearing period and during antemortem events is an inevitable source of animal stress that can have negative impacts on the quality of meat, resulting in economic losses for the meat industry. This study assesses the breed, the farm management system, and the pre-mortem handling of animals and their impact on serum stress biomarkers, as well as their relationship with pH_u. The findings indicate that breed, together with farm management, had the highest impact; cortisol, lactate, and serum amyloid A were identified as potential stress biomarkers in relation to pH_u. We believe that these findings might help in the assessment of stress in cattle at the stage prior to slaughter.

Abstract

Seventy-eight calves from Asturiana de los Valles, Retinta, and Rubia Gallega breeds, under extensive and intensive farm systems and animal mixing and non-mixing conditions, and during the transport and lairage in slaughterhouses, were studied. This research aimed to study the effect of breed, farm system and mixing conditions on serum biomarkers (cortisol, lactate, glucose, serum amyloid A, haptoglobin, and C-reactive protein) and their relationship with pH_u at slaughter time, and to evaluate the response of the serum biomarkers of calves throughout fattening period. Moreover, this study aims to evaluate the response of the biomarkers in each breed during the fattening period. At slaughter time, cortisol and lactate were affected by BreedxFarm; Retinta showed the opposite pattern to the others and revealed the highest glucose in extensive farm systems. Rubia Gallega in mixing revealed the highest Amyloid A and haptoglobin. Extensive calves in mixing conditions showed the highest glucose. There was a relationship among the variables cortisol, lactate, Amyloid A, and pH_u. Slaughter time was a major stressor, and the stress response was mainly affected by breed. At slaughter, several biomarkers should be considered.

Protein Biomarkers of Bovine Defective Meats at a Glance: Gel-Free Hybrid Quadrupole-Orbitrap Analysis for Rapid Screening

An understanding of biological mechanisms that could be involved in the stress response of animal cattle prior to slaughter is critical to create effective strategies aiming at the production of high-quality meat. The sarcoplasmic proteome of directly extracted samples from normal and high ultimate pH (pHu) meat groups was studied through a straightforward gel-free strategy supported by liquid chromatography hybrid quadrupole-Orbitrap high-resolution mass spectrometry (LC-HRMS) analysis. A stepped proteomic pipeline combining rapid biomarker hunting supported by qualitative protein Mascot scores followed by targeted label-free peptide quantification revealed 26 descriptors that characterized meat groups assayed. The functional study of the proposed biomarkers suggested their relevant role in metabolic, chaperone/stress-related, muscle contractility/fiber organization, and transport activities. The efficiency, flexibility, rapidity, and easiness of the methodology proposed can positively contribute to the creation of innovative proteomic alternatives addressing meat quality assessment.

Proteomic pipeline for biomarker hunting of defective bovine meat assisted by liquid chromatography-mass spectrometry analysis and chemometrics

A wide variety of factors prior to slaughter may affect the stress status of beef cattle, giving rise to well-known 'dark-cutting' defective meats characterised by a high ultimate pH (pHu). To understand the underlying mechanisms of pHu fluctuations in beef cattle there was studied the proteome changes caused by pre-slaughter stress through a gel-free proteomic approach. Comparative peptidomic analysis was carried out on 12 loin samples at 24 h post-mortem from Longissimus thoracis et lumborum bovine muscle of crossbred animals, previously sorted into two different groups according to their pHu values: normal (pHu < 6.0) and high (pHu ≥ 6.0). Tryptic peptides from direct protein extracts were approached by combining untargeted (intact mass, MS¹) and targeted (Selected Reaction Monitoring, SRM) quantitative LC-MS assays followed by chemometric analysis. Seventeen peptide biomarkers belonging to 10 different proteins appropriately discriminated sample groups assayed. Results may promote the use of this simple and effective methodology towards the creation of new insights in meat quality research. SIGNIFICANCE: The significance of this study was the optimization of an affordable straightforward gel-free proteomic approach addressing the differentiation of the muscle sub-proteome of normal and high pHu meat samples. This strategy allowed the study of tryptic peptides from direct meat protein extracts by combining untargeted MS¹ and targeted SRM quantitative assays performed by conventional LC-MS detection. Affordability, simplicity and robustness of this methodology can facilitate its readily implementation in routine protocols for quality assessment of meat.

Sensory and Physicochemical Analysis of Meat from Bovine Breeds in Different Livestock Production Systems, Pre-Slaughter Handling Conditions and Ageing Time

Different bovine breeds and production systems are used worldwide, giving rise to differences in intrinsic and extrinsic characteristics of beef. In order to meet the consumer requirements, new approaches are currently being developed to guarantee tenderness, taste, and juiciness of beef. However, the final consumer perception is complex, and it is also affected by several interrelated variables. This study aimed to evaluate the physicochemical parameters and sensory profile of three Spanish cattle breeds under different livestock production systems (extensive and intensive) and pre-slaughter handling conditions (mixing and not mixing with unfamiliar individuals at pre-mortem time). Meat samples from each group were also studied at different ageing times (7 and 14 days). Regarding sensory attributes, twelve panelists assessed meat samples and an exhaustive statistical analysis was carried out. The most evident and strongest effect was the breed type, allowing a great differentiation among them using principal components and discriminant analysis. The livestock production system was the second most important parameter, significantly affecting odor, flavor, and textural profile (fibrousness). It can be concluded that there were marked differences in the traits of these beef that could be modified by other factors in order to fulfill consumer tastes.

Overweight in the Elderly Induces a Switch in Energy Metabolism that Undermines Muscle Integrity

Aging is characterized by a progressive loss of skeletal muscle mass and function (sarcopenia). Obesity exacerbates age-related decline and lead to frailty. Skeletal muscle fat infiltration increases with aging and seems to be crucial for the progression of sarcopenia. Additionally, skeletal muscle plasticity modulates metabolic adaptation to different pathophysiological situations. Thus, cellular bioenergetics and mitochondrial profile were studied in the skeletal muscle of overweight aged people without reaching obesity to prevent this extreme situation. Overweight aged muscle lacked ATP production, as indicated by defects in the phosphagen system, glycolysis and especially mostly by oxidative phosphorylation metabolic pathway. Overweight subjects exhibited an inhibition of mitophagy that was linked to an increase in mitochondrial biogenesis that underlies the accumulation of dysfunctional mitochondria and encourages the onset of sarcopenia. As a strategy to maintain cellular homeostasis, overweight subjects experienced a metabolic switch from oxidative to lactic acid fermentation metabolism, which allows continued ATP production under mitochondrial dysfunction, but without reaching physiological aged basal levels. This ATP depletion induced early signs of impaired contractile function and a decline in skeletal muscle structural integrity, evidenced by lower levels of filamin C. Our findings reveal the main effector pathways at an early stage of obesity and highlight the importance of mitochondrial metabolism in overweight and obese individuals. Exploiting mitochondrial profiles for therapeutic purposes in humans is an ambitious strategy for treating muscle impairment diseases.

Sedentarism and overweight as risk factors for the detection of prostate cancer and its aggressivenes

OBJECTIVE

To analyze the influence of sedentary (SE) and overweight (OW) in the risk of prostate cancer detection (CP) and aggressiveness.

MATERIAL AND METHOD

We performed prostate biopsy (PB) to 2,408 consecutive male, 5 ARIs untreated, because of elevated serum PSA above 4.0 ng/mL (91%) or suspicious digital rectal examination (9%). In all ultrasound guided PB, 10 cores were obtained plus 2 to 8 additionals, according to age and prostate volume. Physical activity was assessed using a survey (SE vs non-SE) and calculated body mass index (normal vs OW > 25 kg/cm(2)). The tumor aggressiveness was evaluated according to the Gleason score (high grade «HG»: Gleason > 7) and D'Amico risk (high risk «HR»: T > 3a or PSA > 20 or Gleason score > 7).

RESULTS

We found a significant association between SE (52.5%) and OW (72.9%), P < .001. The overall PC detection rate was 35.2%. In men with SE it was 36.7% and non-SE 33.6%, P = .048. The overall rate of AG tumors was 28.3%, 29.2% in men with SE and 27.1 in non-SE, P = .261. The overall rate of AR tumors was 35%, 39.7% in men with SE and 29.4% non-SE, P < .001. CP was detected in 38.1% of men with normal BMI and 34.3% in men with OW, P = .065. HG tumor rates were 18.1% and 31.4% respectively, P < .001 and AR tumor rates were 22.6% and 39.2% respectively, P < .001. Binary logistic regression showed that SE was an independent predictor of CP, OR .791 (95% CI: .625-.989), P = .030. SE and OW were independent predictors of HG: OR .517 (95% CI: .356-.752), P = .001, and OR 1.635 (95% CI: 1070-2497), p = 0.023. SE and OW were also independent predictors of HR: OR .519 (95% CI .349-.771), P = .001, and OR 1.998 (95% CI 1.281-3.115), P = .002.

CONCLUSIONS

In men who met criteria for prostate biopsy an association between sedentary and overweight exist. A sedentary lifestyle is associated with increased risk of PC detection while sedentary and overweight were associated with more aggressive tumors.

Autophagy during beef aging

The conversion of muscle into meat is a complex process of major concern for meat scientists due to its influence on the final meat quality. The aim of this study was to investigate the occurrence of autophagic processes in the conversion of muscle into meat. Our findings demonstrated, for the first time, the occurrence of autophagic processes in the muscle tissue at early postmortem period (2 h to 24 h) in both beef breeds studied (Asturiana de los Valles and Asturiana de la Montaña) showing significant time-scale differences between breeds, which could indicate a role of this process in meat maturation. These breeds have different physiological features: while Asturiana de los Valles is a meat-specialized breed showing high growth rate, an elevated proportion of white fibers in the muscle and low intramuscular fat level, Asturiana de la Montaña is a small- to medium-sized rustic breed adapted to less-favored areas, showing more red fibers in the muscle and a high intramuscular fat content.

Identification of biomarkers of meat tenderisation and its use for early classification of Asturian beef into fast and late tenderising meat

BACKGROUND

The objective of this work was to study the post-mortem evolution of potential biomarkers (µ-calpain activity and proteolytic profile) of meat tenderisation in bovine longissimus dorsi (LD) muscle from several biotypes coming from two beef breeds ('Asturiana de los Valles' and 'Asturiana de la Montaña') and showing different levels of muscular hypertrophy (mh/mh, mh/+, + /+).

RESULTS

LD samples were taken at 2, 12, 24 and 48 h and 3, 7, 14 and 21 days post-mortem. The presence of muscular hypertrophy produced a faster rate of pH decline, faster exhaustion of µ-calpain activity and earlier occurrence of proteolytic changes. Changes in the electrophoretic pattern of some peptides from sarcoplasmic (glyceraldehyde-3-phosphate dehydrogenase) and myofibrillar (troponin T and troponin I) muscle extracts within the first 24 h significantly correlated with meat toughness and allowed accurate discrimination of meat products into two groups: (1) fast tenderising meat, coming from mh-biotypes, and (2) late tenderising meat, from normal (+/+) biotypes.

CONCLUSION

Early monitoring (within 24 h after slaughter) of selected biomarkers in LD muscle allowed accurate prediction of ultimate meat toughness and could be used in the meat industry as a tool for early classification of beef into fast and late tenderising meat.

Application of n-alkanes as diet composition markers in grazing/browsing goats and sheep: effect of using different faecal recovery corrections and plant species grouping approaches

The present study aimed to test the effect of applying different sets of n-alkane faecal recoveries and different plant species grouping approaches on the estimates of the diet selected by goats and sheep when grazing/browsing complex vegetation communities composed of mosaics of heather-gorse vegetation interspersed with patches of perennial ryegrass. The use of different sets of n-alkane faecal recoveries significantly affected the estimated proportions of most vegetation components in both animal species. The diet estimates were also significantly affected by the calculation approach: A1 (using all individual plant species); A2 (grouping plant species with similar n-alkane profile, with equal weighting within the group); and A3 (grouping plant species with similar n-alkane profile, with different weighting according to the botanical composition of the plot). There was a significant interaction between calculation approach (A) and faecal recovery sets (FR) on the resulting estimates of the Ericaceae species in the diet of goats and of all diet components in sheep. When using A1 approach, the estimated proportion of Agrostis capillaris in the diets was high and seemed to be overestimated, compared with its low availability (1.1% of total cover) in the field. However, the application of calculation approaches A2 and A3 gave lower dietary proportions of component D2 (Agrostis capillaris and Ulex gallii) and higher proportions of components D1 (Lolium perenne and Pseudarrhenatherum longifolium), D3 (Erica umbellata, Erica cinerea, Erica australis, Calluna vulgaris) and Erica arborea. These results indicate that the application of the n-alkane technique for estimation of the diet composition in field with complex vegetation conditions is sensitive to the use of faecal recovery corrections and to the grouping of possible dietary components.

[Intraparotid lymphoepithelial cysts and the human immunodeficiency virus]

Lymphoepithelial lesions in the parotid gland are an uncommon benign entity, with an increasing incidence since 1980 due to the involvement of HIV infected patients. We report here three cases recorded at the ORL service in Viladecans Hospital, with cytologic investigation with echo-guided fine needle aspiration. A discussion follows on the theory that these cysts are part, together with persistent polyadenopathies, of the immune response to HIV infection. The course towards malignancy is exceptional and conservative management is most accepted.

[Multiple radicular tumors in von Recklinghausen disease assessed by magnetic resonance]

We present a case of multiple neurofibromata at lumbar nerve root level in a patient diagnosed as having Von Reckling-hausen's disease or type 1 neurofibromatosis (NF 1), studied using magnetic resonance (MR). We also observed in the same study the presence of dural ectasis, something likewise related to NF 1. We assessed MR possibilities in the study of this type of pathology and its relative advantages with respect to other types of image-forming techniques. MR is nowadays considered as the technique of choice when studying medullar and radicular pathology in patients suffering Von Recklinghausen's disease.

[Evidence of infection by HIV-2 in Madrid (1991)]

The presence of antibodies against HIV-2 was analyzed in serum samples from high-risk individuals for retrovirus infection, who were seropositives for HIV-1. Out of a total of 842 samples, 344 presented positive absorbency and 16, threshold ranges, in an enzymatic immunoassay (EIA) designed to detect simultaneously antibodies against HIV-1 and HIV-2. The Western Blot (WB) analysis confirmed the presence of antibodies against HIV-1 in 324 samples with positive or threshold EIA, while it was indetermined in 15 samples. WB was negative in 11 samples. In the 15 samples with indetermined WB and in the 16 samples with threshold EIA, the presence of antibodies against HIV-2 was investigated with an specific WB and a test designed with synthetic peptides (Pepti-lav). Three samples met the isolated seropositivity criteria for HIV-2. Those samples were from 3 african immigrants living in Madrid, which, until now, were asymptomatic, although one of them presented biological signs of immunodeficiency. None of them referred high-risk infectious practices, such a homosexuality or drug-addiction, although all of them referred heterosexual contacts in their native countries. Samples from native subjects meeting serum positivity criteria for HIV-2 were not identified.