Post-mortem characterization of Dorper x Santa Inês lambs fed diets containing alternative foods

The objective of this study was to evaluate the post-mortem characteristics of lambs fed diets containing alternative foods. Twenty lambs, castrated Dorper x Santa Inês males, aged approximately 90 days and with mean weight of 20 kg were used. Experimental diets were composed of ground corn, soybean meal, mineral supplement, urea and Tifton-85 hay (forage). In addition to these ingredients, cottonseed, sunflower meal and castor bean cake were used as alternative foods in the proportions of 10, 8 and 8% of %DM, respectively. The experiment lasted 106 days, with 14 days for adaptation and 92 days for evaluation and data collection. At the end of the confinement period, the lambs were slaughtered, and the carcasses kept under cooling for a period of 24 hours. The measurements of pH, carcass temperature (internal and external) were measured in the Longissimus lumborum muscle, as well as the temperature and relative humidity of the cold chamber were measured. Muscle pH was altered as a function of diet and reached a value of 5.78 (lower pH) when lambs received the diet with castor bean cake. The internal carcass temperature was higher in the lambs that received the diet containing cottonseed (19.98°C), sunflower meal (19.71°C) and castor bean cake (19.87°C). The alternative foods can be used as ingredients in the formulation of diets for Dorper x Santa Inês lamb, for promoting the proper development of the post-mortem process, characteristic of good quality sheep meat.

Integrative surveillance of cattle welfare at the abattoir level: Risk factors associated with liver condemnation, severe hoof disorders, carcase bruising and high muscle pH

Given the multi-dimensionality of animal welfare, any monitoring system for slaughter animals should comprise an integrative vision that facilitates animal welfare and food safety assessment. Thus, the aim of this study was to investigate risk factors as possible causes for liver condemnations, hoof disorders, bruise prevalence, and the quality of beef carcases under commercial operating conditions in Mexico. Data were recorded for 143 journeys encompassing 1,040 commercial cattle, originating from feedlots, free-range, and dairy production systems. Details on journey distance, vehicle type, cattle type, and animals' origin were gathered from abattoir reports. We found that carcase bruising (41%) and hoof disorders (43.9%) had the highest prevalence, regardless of the production system. Variables such as cattle type and production system influenced liver condemnations; old bulls extensively raised were more prone to present parasitosis such as Fasciola hepatica. Transportation conditions (journey distance, vehicle type) and cattle type might have influenced the development of hoof disorders in the evaluated animals. Multivariable logistic regression showed that animals' origin was a potential risk factor for severe bruising and high muscle pH, with cull dairy cows getting the most serious damage. In general, cattle transport conditions were factors that showed interactions with three of the evaluated indicators (severe hoof injuries, carcase bruising, meat pH24h). Our study shows the need to implement integrative surveillance to identify risk factors according to the production system from which the animals originate. With this information it is possible to develop strategies to mitigate specific cattle welfare problems.

Electrical stimulator voltage settings minimally influences beef longissimus muscle tenderness

The objective of the current study was to evaluate the effect of differing electrical stimulation (ES) voltage levels on beef longissimus muscle (LM) tenderness, postmortem temperature, and pH decline, and carcass quality. Beef carcasses from three commercial beef processing plants (A, B, C) were exposed to three varying voltage levels: 1) control (no ES) 2) high ES (60-Hz for 17s each at 25, 35, 45, and 55 V) 3) low-ES (60-Hz for 17s each at 16, 20, 24, and 28 V). Ninety beef carcasses were selected from the three plants, and within a carcass, paired sides were randomly assigned to one of three ES treatments. The results indicated that ES affected (P < 0.05) muscle pH at 3 h postmortem in two of the three plants. However, ES did not affect (P > 0.05) pH at the time of grading (post rigor). Although the slice shear force (SSF) values were lower (P < 0.05) for ES steaks compared to controls, it was not (P < 0.05) influenced by the voltage levels. Variation in tenderness was observed among the plants (P < 0.05), with Plant C having the toughest steaks, whereas Plant A and B exhibited similar (P > 0.05) tenderness. Overall, the lack of difference in postmortem tenderness between high- and low-voltage settings indicated the ES-voltage minimally influenced tenderness. 

Real time measurement of intramuscular pH during routine knee arthroscopy using a tourniquet

Aims Tourniquets have potential adverse effects including postoperative thigh pain, likely caused by their ischaemic and possible compressive effects. The aims of this preliminary study were to determine if it is possible to directly measure intramuscular pH in human subjects over time, and to measure the intramuscular pH changes resulting from tourniquet ischaemia in patients undergoing knee arthroscopy. Methods For patients undergoing short knee arthroscopic procedures, a sterile calibrated pH probe was inserted into the anterior fascial compartment of the leg after skin preparation, but before tourniquet inflation. The limb was elevated for three minutes prior to tourniquet inflation to 250 mmHg or 300 mmHg. Intramuscular pH was recorded at one-second intervals throughout the procedure and for 20 minutes following tourniquet deflation. Probe-related adverse events were recorded. Results A total of 27 patients were recruited to the study. Mean tourniquet time was 21 minutes (10 to 56). Tourniquet pressure was 300 mmHg for 21 patients and 250 mmHg for six patients. Mean muscle pH prior to tourniquet inflation was 6.80. Muscle pH decreased upon tourniquet inflation, with a steeper fall in the first ten minutes than for the rest of the procedure. Change in muscle pH was significant after five minutes of tourniquet ischaemia (p < 0.001). Mean muscle pH prior to tourniquet release was 6.58 and recovered to 6.75 within 20 minutes following release. No probe related adverse events were recorded. Conclusion It is possible to directly measure skeletal muscle pH in human subjects over time. Tourniquet ischaemia results in a decrease in human skeletal muscle pH over time during short procedures. Cite this article: Bone Joint Res 2021;10(6):363–369.

Low-Voltage Electrical Stimulation of Beef Carcasses Slows Carcass Chilling Rate and Improves Steak Color

Electrical stimulation (ES) is used in beef slaughter plants to improve tenderness; however, varying levels of low-voltage ES have not been well characterized. The objective was to evaluate the influence of two levels of low-voltage ES on temperature decline, pH, glycolytic potential, and meat quality. Forty-two beef carcasses were chosen from a commercial packing facility. One side of each carcass received either 40 or 80 volts of ES for 60 s at 45 min postmortem. The paired side of each carcass did not receive ES (Control). Temperature loggers were placed in the sirloin of 12 carcasses to record temperature decline. Longissimus muscle pH was measured at 1, 12, and 24 h, and 3 d postmortem. Strip steaks were fabricated for determination of meat quality. A treatment by time interaction was observed for carcass temperature decline (p < 0.001) where ES sides stayed warmer longer than Control sides. A treatment by time interaction was observed for pH decline with Control sides exhibiting an increased pH at 1 h postmortem (p < 0.001). Instrumental color values were increased for ES compared to Control sides (p < 0.001). These results indicate ES slows carcass temperature decline, hastens initial pH decline, and improves instrumental color. Similar results were observed between the ES treatments indicating either ES level may be used to achieve similar quality characteristics.

Changes in Metabolite and Protein Expression Profiles of Atypical Dark-cutting and Normal-pH Beef

The color of meat is an important deciding factor in consumers’ assessment of meat quality. To meat buyers, the bright cherry-red color of meat indicates freshness and wholesomeness. However, atypical dark-cutting beef represents dark-colored meat with a muscle pH between 5.6 and 5.8. Although previous studies have indicated that the ultimate pH of atypical dark-cutting beef is greater than normal, the mechanistic basis for the occurrence is not clear. Therefore, the objective of this study was to identify protein and metabolite profiles of normal and atypical dark-cutting beef. Longissimus thoracic (LT) muscles from 12 different animals (6 atypical dark-cutters and 6 normal-pH beef) were analyzed by comparing changes in metabolites and protein profiles using GC-MS non-targeted metabolomics and LC-MS/MS-based proteomics, respectively. Metabolomics analysis showed down-regulation of glycolytic metabolites such as glucose-6-phosphate, lactose, and glucose, indicating a reduced capacity to accumulate lactate postmortem in atypical dark-cutters compared with normal-pH beef. Mass spectrometry analysis identified 66 proteins with significant changes in protein expression profiles (P &lt; 0.05) between atypical and normal-pH beef. Of these, 22 proteins were up-regulated while 14 were down-regulated in atypical dark-cutting beef. Functional annotation and protein-protein interaction network analyses revealed that up-regulated proteins such as NADH ubiquinone oxidoreductase subunit A7, ATPase Na+/K+ transporting subunit alpha 2, 3-oxoacid CoA-transferase 1, cytochrome b5 reductase 3, actinin alpha 4, tropomyosin 2, heat shock protein beta-7, and DnaJ heat shock protein family (Hsp40) member B4 are involved in energy synthesis, muscle contraction and stress responses. By contrast, down-regulated proteins, including phosphofructokinase, glycogen phosphorylase, amylo-alpha-1,6-glucosidase, phosphorylase kinase regulatory subunit alpha and gamma are involved in glycogen metabolism. In summary, lower glycolytic metabolites and glycogen degradation enzymes are associated with differences in muscle pH and color of atypical dark-cutting beef.