Effect of porcine somatotropin and stress susceptibility on the sensory, physical and chemical properties of porcine skeletal muscle

Forty-eight pigs of three genetically defined phenotypes (stress positive, stress carrier and stress negative) were injected daily with recombinant porcine somatotropin (PST) (4 mg/day) or placebo, and the effects of PST along with stress susceptibility on the sensory, physical, chemical and processing characteristics of pork longissimus and semimembranosus (SM) muscle were observed. Two end-point temperatures (71° and 77°C) were used for sensory analysis of broiled pork chops;PST treatment significantly lowered panel scores for tenderness, juiciness and flavor of broiled pork chops, while stress susceptibility decreased panel scores for tenderness only. PST treatment reduced intramuscular fat and increased moisture in the longissimus muscle, but PSE had no effect on proximate composition. PST treatment and stress susceptibility decreased and increased Hunter L values of chops, respectively. Furthermore, higher end-point temperature of broiled pork chops reduced sensory scores for tenderness and juiciness;PST treatment of animals had no effect on the sensory scores, lipid and protein content, cook yields, or color values of hams. Hams from stress susceptible animals, however, had reduced sensory scores, lower cook yields, and higher Hunter a and b values, and significantly lower lipid content. No interaction between PST treatment and stress classification was observed for any of the measurements;In the second study, the effect of the porcine stress syndrome on the solubility and degradation of sarcoplasmic and myofibrillar/cytoskeletal proteins was investigated. Longissimus dorsi muscle samples were obtained from each of 6 stress positive, 6 stress negative and 5 stress carrier animals 45 minutes post-slaughter and on 1, 3, 5, and 7 days postmortem. Purified myofibrils were prepared for gel electrophoresis, and muscle samples were extracted with phosphate buffers containing KCl or KI. Samples for SDS-PAGE were made from each extraction to observe changes in solubility of individual proteins. Sarcoplasmic and myofibrillar/cytoskeletal protein solubility was significantly lower in muscle samples from stress positive animals and the reduction was uniform among proteins. Postmortem degradation of titin was different in myofibrils purified from stress positive animals in that no increase in the intensity of T[subscript]2 bands at days 5 and 7 was observed. The combination of reduced solubility and degradation of structural constraints may explain the reduced water-holding capacity (WHC) and functionality of PSE muscle

Cooked turkey roasts have different processing characteristics then cooked beef roasts

Roasts were manufactured from lean beef and turkey by injecting with brine to 25% above green weight so the raw product contained 1.8% salt and 0.3% sodium phosphate. Meat muscle characteristics (pH and protein solubility) and processing characteristics were measured as cook yields and expressible moisture. The species significantly affects some basic properties of the meat. Turkey meat had significantly higher pH and extractible myofibrillar proteins than beef. The increased cook yield was correlated with higher pH and higher expressible moisture. The differences observed suggest that processors need to treat the starting materials differently

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Gene Expression and Carcass Traits Are Different between Different Quality Grade Groups in Red-Faced Hereford Steers

Fat deposition is important to carcass value and some palatability characteristics. Carcasses with higher USDA quality grades produce more value for producers and processors in the US system and are more likely to have greater eating satisfaction. Using genomics to identify genes impacting marbling deposition provides insight into muscle biochemistry that may lead to ways to better predict fat deposition, especially marbling and thus quality grade. Hereford steers (16) were managed the same from birth through harvest after 270 days on feed. Samples were obtained for tenderness and transcriptome profiling. As expected, steaks from Choice carcasses had a lower shear force value than steaks from Select carcasses; however, steaks from Standard carcasses were not different from steaks from Choice carcasses. A significant number of differentially expressed (DE) genes was observed in the longissimus lumborum between Choice and Standard carcass RNA pools (1257 genes, p < 0.05), but not many DE genes were observed between Choice and Select RNA pools. Exploratory analysis of global muscle tissue transcriptome from Standard and Choice carcasses provided insight into muscle biochemistry, specifically the upregulation of extracellular matrix development and focal adhesion pathways and the downregulation of RNA processing and metabolism in Choice versus Standard. Additional research is needed to explore the function and timing of gene expression changes