Relationship of glycogen and lactate concentrations as a pork quality indicator

Muscle metabolites greatly determine pork quality. However, precise threshold values which indicate its deterioration or improvement are not fully known. This study aimed to determine the influences of pork Longissimus lumborum (LL) glycogen and lactate concentrations measured at 45 min post mortem on pH, colour (L*a*b*) and drip loss (DL) measured during 144 hours post mortem in order to prescribe appropriate threshold values. The investigation used 30 gilts and 30 barrows being fattened for slaughter. After slaughter, the carcasses were assigned to groups based on the observed levels of glycogen and lactate: low GlyL with glycogen ≤35 μmol/g, GlyM with glycogen between 35 and 55 μmol/g, GlyH with glycogen >55 μmol/g; LacL with lactate ≤40 μmol/g and LacH with lactate >40 μmol/g. Lower muscle pH was noted up to 24 h post mortem in the LacH group compared to LacL (P ≤0.01). 24 h post mortem higher pH was found in GlyL than in GlyM and GlyH (P ≤0.01), which were similar. Similarly no statistical differences were noted between The GlyM and GlyH groups were also similar in L*, DL96 and DL144, with lower values found for GlyL (P ≤0.01). Compared to LacH, LacL had lower L*, DL48, DL96 and DL144 (P ≤0.01) and higher a* and b* values. Muscle pH, drip loss, L* and a* values were more affected by lactate concentration if the glycogen concentration ≥35 μmol/g muscle tissue. Thus, metabolite concentration may be a useful and valuable indicator of pork quality. Keywords: drip loss, glycolytic resources, pork colour, post-mortem muscle metabolis

Efficacy of home-based physical activity interventions in patients with autoimmune rheumatic diseases: A systematic review and meta-analysis

Introduction: Physical activity (PA) has been receiving increasing interest in recent years as an adjuvant therapy for autoimmune rheumatic disease (ARDs), but there is scarce information about the efficacy of home-based PA for patients with ARDs. Objective: To perform a systematic review and meta-analysis on the efficacy of home-based physical activity (PA) interventions in improving health-related quality of life, functional capacity, pain, and disease activity in patients with ARDs. Methods: Searches were performed in PubMed, Web of Science, Scopus, Cochrane, CINAHL database and Sport Discus. Trials were considered eligible if they included a home-based physical activity intervention. The population included adults with autoimmune rheumatic diseases (e.g., rheumatoid arthritis, systemic lupus erythematosus, idiopathic inflammatory myopathies, systemic sclerosis and ankylosing spondylitis), comparisons included non-physical activity control or centre-based interventions (i.e., interventions performed on a specialized exercise centre) and the outcomes were quality of life, pain, functional capacity, disease activity and inflammation. Results: Home-based physical activity improved quality of life (p<0.01; g = 0.69; IC95%, 0.61 to 1.07) and functional capacity (p = 0.04; g = - 0.51; IC95%, -0.86; -0.16), and reduced disease activity (p = 0.03; g = - 0.60; IC95%, -1.16; -0.04) and pain (p = 0.01; g = -1.62; IC95%, -2.94 to -0.31) compared to the non-physical activity control condition. Additionally, home-based physical activity interventions were as effective as centre-based interventions for all investigated outcomes. Conclusion: Home-based PA is an efficacious strategy to improve disease control and aleviate symptoms in ARD

Effects of physical activity on vascular function in autoimmune rheumatic diseases: A systematic review and meta-analysis

Objectives: To summarize existing evidence and quantify the effects of physical activity on vascular function and structure in autoimmune rheumatic diseases (ARDs). Methods: Databases were searched (through March 2020) for clinical trials evaluating the effects of physical activity interventions on markers of micro- and macrovascular function and macrovascular structure in ARDs. Studies were combined using random effects meta-analysis, which was conducted using Hedges' g. Meta-analyses were performed on each of the following outcomes: microvascular function [i.e. skin blood flow or vascular conductance responses to acetylcholine (ACh) or sodium nitropusside (SNP) administration]; macrovascular function [i.e. brachial flow-mediated dilation (FMD%) or brachial responses to glyceryl trinitrate (GTN%); and macrovascular structure [i.e. aortic pulse wave velocity (PWV)]. Results: Ten studies (11 trials) with a total of 355 participants were included in this review. Physical activity promoted significant improvements in microvascular [skin blood flow responses to ACh, g = 0.92 (95% CI 0.42, 1.42)] and macrovascular function [FMD%, g = 0.94 (95% CI 0.56, 1.02); GTN%, g = 0.53 (95% CI 0.09, 0.98)]. Conversely, there was no evidence for beneficial effects of physical activity on macrovascular structure [PWV, g = -0.41 (95% CI -1.13, 0.32)]. Conclusions: Overall, the available clinical trials demonstrated a beneficial effect of physical activity on markers of micro- and macrovascular function but not on macrovascular structure in patients with ARDs. The broad beneficial impact of physical activity across the vasculature identified in this review support its role as an effective non-pharmacological management strategy for patients with ARDs

pH measured 24 hours post mortem should not be regarded as ultimate pH in pork meat quality evaluation

The aim of this study was to compare the diagnostic values of two methods in pork meat quality evaluation, that is, Method I: pH1 and pH24 and Method II: electrical conductivity (EC2) and pH24, which included pH24, and their modifications, that is, Method III: pH1 and pH48 and Method IV: EC2 and pH48, which included pH48 measurement. Five meat quality classes, namely reddish-pink, firm and non-exudative (RFN), high quality (HQ), pale, soft and exudative (PSE), dark, firm and dry (DFD) and acid meat (AM) were assessed in four even-numbered genetic groups of 40 fatteners each, namely (L×Y)×D-A, (L×Y)×D-B, (L×Y)×H and (L×Y)×(D×P). The change of diagnostic method and therefore pH time measurement from 24 hours to 48 hours post mortem caused a major increase in the percentage of acid meat (AM) that was diagnosed. Most differences were observed in (L×Y)×H fatteners, namely 77.5% between Methods I and III and 75% between Methods II and IV. This increase in AM frequency indicates that as a result of significant changes in the post-mortem metabolism that occur in the meat ageing process pH48 should be regarded as ultimate pH (pHu). Keywords: Acid meat, fatteners, post-mortem muscle metabolis

The influence of the season of slaughter and hot carcass weight on the meatiness of fatteners from the mass population

Celem pracy była analiza oddziaływania pory roku wykonania uboju i masy tuszy ciepłej na mięsność tusz tuczników z chowu masowego, pochodzących z zaplecza surowcowego jednego z zakładów mięsnych środkowo-wschodniej Polski. Materiał badawczy stanowiło ogółem 8820 tusz zwierząt ubijanych w 2012 roku: zimą (luty) – 1861 szt., wiosną (maj) – 2334 szt., latem (lipiec) – 2127 szt. i jesienią (październik) – 2498 szt. Procentową zawartość mięsa w tuszy oszacowano za pomocą aparatu ultradźwiękowego ULTRA FOM 300 duńskiej firmy SFK-Technology. Dodatkowo, analizowany materiał badawczy podzielono na trzy grupy zróżnicowane masą tuszy ciepłej (MTC): I – MTC 87 kg. Stwierdzono, że pora roku wykonania uboju istotnie różnicowała procentową zawartość mięsa w tuszy oraz grubość mięśnia LD i słoniny. Największą mięsność oraz najmniejsze otłuszczenie badanych tusz odnotowano w grupie tuczników ubijanych zimą. Dokonując uboju zwierząt o masie tuszy ciepłej przekraczającej 87 kg należy liczyć się zarówno ze spadkiem średniej mięsności (o ok. 0,8 p.p.), jak i znacznym wzrostem otłuszczenia (o ok. 2-3 mm) w stosunku do tusz lżejszych (o masie nie przekraczającej 87 kg). Uwzględniając interakcję pory roku i masy tuszy ciepłej, najkorzystniejszymi wartościami analizowanych cech charakteryzowały się tusze o masie od 79 do 87 kg. W zakresie mięsności, jak i grubości słoniny w punkcie S1 tusze te (z wyjątkiem grubości słoniny w punkcie S1 zmierzonej zimą) nie różniły się statystycznie w poszczególnych porach roku od tusz, których masa nie przekraczała 79 kg, zaś grubość mięśnia LD (z wyjątkiem jesieni) miały zbliżoną do tusz najcięższych (o masie powyżej 87 kg).The aim of this study was to analyse the influence of the season of slaughter and hot carcass weight (HCW) on the meatiness of fatteners from the mass population, obtained from one of the meat plants located in central-eastern Poland. The investigations were conducted in 2012 on a total of 8,820 fatteners, in winter (February) – 1,861 carcasses, spring (May) – 2,334, summer (July) – 2,127 and autumn (October) – 2,496. Lean meat content was estimated using an ULTRA FOM 300 apparatus manufactured by the Danish company SFK-Technology. Additionally, the study material was assigned to three groups according to hot carcass weight (HCW): I – HCW <79 kg, II HCW – 79-87 kg and III – HCW >87 kg. The season of the slaughter was found to the influence the meatiness of the carcass, the thickness of the Longissimus dorsi (LD) muscle, and fat thickness. The highest meatiness and lowest fat thickness were noted in the carcasses of fatteners slaughtered in winter. Heavier animals (with hot carcass weight above 87 kg) were shown to have lower meatiness by about 0.8 percentage points and about 2-3 mm greater fat thickness than lighter ones (HCW below 87 kg). There was also found to be an interaction between the season of the slaughter and hot carcass weight for the traits analysed. Favourable meatiness and fat thickness at the S1 point was noted for carcasses with HCW from 79 to 87 kg. Except in winter, their meatiness and fat thickness at the S1 point was similar to that of the lightest carcasses (HCW below 79 kg), while longissimus muscle thickness (except in autumn) was at the level of the heaviest carcasses (with HCW above 87 kg)

Usefulness of selected parameters determined 45 minutes post mortem in Longissimus lumborum muscle to evaluate pork quality

Celem przeprowadzonych badań było określenie przydatności takich parametrów, jak: zawartość kwasu mlekowego i glikogenu, pH₄₅ oraz przewodność elektryczna (EC₂) w mięśniu Longissimus lumborum (LL) do oceny jakości wieprzowiny. Wymienione parametry oznaczano 45 min post mortem, a dodatkowo przewodność elektryczną mierzono po 2, 3 i 24 h po uboju. Wykazano większą przydatność oznaczania zawartości kwasu mlekowego i EC₂ w mięśniu LL do oceny jakości wieprzowiny. Potwierdzeniem są statystycznie istotne zależności tych parametrów od większości cech fizykochemicznych mięśnia LL. Statystycznie istotna (p ≤ 0,01) ujemna zależność pomiędzy zawartością kwasu mlekowego oznaczonego 45 min post mortem a pH₄₅ mięśnia LL (r = -0,72**) wskazuje na przydatność wykorzystania tych pomiarów do oceny jakości wieprzowiny. Wzrost zawartości kwasu mlekowego (45 min post mortem) o 10 μmol/g tkanki mięśniowej przyczynia się do obniżenia pH45 mięśnia LL aż o 0,1 jednostki.The objective of the research performed was to evaluate the usefulness of the following parameters: contents of lactic acid and glycogen, pH₄₅, and electrical conductivity (EC₂) in Longissimus Lumborum muscle (LL) to evaluate the quality of pork. The above named parameters were determined 45 min post mortem, and, additionally, the electrical conductivity was measured 2, 3 i 24 h after slaughter. It was proved that the determination of the content of lactic acid and EC₂ in the LL muscle was more useful for the pork quality evaluation. This is confirmed by the statistically significant correlations among those parameters and the majority of physical-chemical properties of the LL muscle. The statistically significant negative correlation (p ≤ 0.01) between the content of lactic acid determined 45 min post mortem and the pH₄₅ value of the LL muscle (r = -0.72**) suggests the usefulness of those parameters in evaluating the pork quality. The increase (45 min post mortem) in the lactic acid content by 10 μmol/1 g of the muscle tissue contributes to the decrease in pH₄₅ of the LL muscle by as much as 0.1 unit