Pre-slaughter Stress Research Articles

Grazing intensity and associated frequency of human contact, and horn status, influence activity on pasture, physiological pre-slaughter reactions and meat quality in beef heifers

Meat quality is influenced by many factors related to the animal, such as its genetics and health status, farm management, and slaughter and processing conditions. The present study aimed to investigate the effects and interactions of grazing intensity and horn status on behaviour, physiological pre-slaughter stress status and meat characteristics of beef heifers. The study involved 32 horned and 32 disbudded F1 crossbred (Limousin ☓ Swiss Dairy breed) heifers during summer grazing on mountain pastures. Half of the heifers of each horn status were assigned to one of two grazing systems, balanced for live weight, dam and behavioural reactivity: grazing at either high (HI) or low (LI) grazing intensity. HI groups grazed in 3 times smaller paddocks and changed the paddock three times more often than LI groups. The effects of horn status and grazing intensity on physical activity on pasture, pre-slaughter stress and meat quality of the m. longissimus thoracis were studied. Compared to HI heifers, LI Heifers walked more when on pasture, showed greater stress levels before stunning, and their meat had greater water losses and greater early troponin levels. The varying pre-slaughter stress levels may be attributed to the differing frequency of human contact resulting from the differing frequency of paddock changes and may explain part of the effects on meat quality. Compared to disbudded heifers, horned heifers had faster heart rates at the abattoir, and their meat had lower cooking loss and was less juicy. Pre-slaughter heart rates showed robust correlations with various meat quality indicators. The study shows that both horn status and grazing management, including human contact, influence meat quality. Part of the effects may be related to different pre-slaughter physiological reactions, which subsequently influence meat quality.

Effects of maternal contact and positive human contact during lactation on pork quality: Positive human contact to piglets during lactation improves pork loin muscle pH

Enhancing stress resilience through the early life period in pigs could potentially improve pork quality. It was hypothesised that pigs receiving maternal contact or positive human contact during lactation would have improved carcass and pork quality. Seventy-nine mixed-sex pigs were selected from a 2 × 2 factorial randomised block design for treatments maternal contact (MC+) / reduced maternal contact (MC-); and positive human contact (HC+) / control (HC-). Modified farrowing crates were utilised to reduce maternal contact (MC-). Litters in the HC+ treatment received five minutes of daily positive human interaction (stroking). Treatments ceased at 22 days of age (weaning) and pigs were slaughtered after 21 weeks of age. The m. longissimus thoracis et lumborum pH was higher in HC+ than HC- pigs (P < 0.05) during chilling, from 90 min post slaughter. No HC effects (P > 0.05) were observed for cortisol or haptoglobin concentration, hot carcass weight, P2 backfat, carcass scratches, colour, drip loss, cook loss and shear force. MC+ tended (P < 0.086) to increase carcass weight, P2 and carcass scratch score compared to MC-, but no further impacts were observed. The impact of positive human contact during early life was observed 20+ weeks after treatment with reduced pH decline, potentially indicating a reduction in pre-slaughter stress, however there were no further impacts on pork quality. There is evidence that maternal contact is important for lifetime growth performance of pigs but the impacts on stress resilience are less apparent.

Types of stress and methods of stress reduction in cattle

Recently, stress has become the most urgent problem of modern animal husbandry. With the industrialization of agriculture, this problem is becoming more and more acute, as a result, livestock enterprises and farms suffer significant economic losses. Throughout its life, the animal is exposed to numerous stressors that have a completely different nature of occurrence, but invariably lead to the same changes in the body. The animal noticeably loses weight, weakens, its resistance to diseases decreases. A review of scientific sources on some types of stress loading on cattle: heat stress, transportation stress, pre-slaughter stress is given. According to many studies, the stress state of an animal depends on feeding and maintenance by 70-80% and only 20-30% on genetics. The body of farm animals is constantly affected by various environmental factors. These include production technology, method of maintenance, density of accommodation, size of groups, microclimate of premises, type and level of feeding, biological full-value of diets, methods of preparation and distribution of feed, quality of drinking water, veterinary and preventive and zootechnical measures (vaccination, sanitary treatment of animals, weighing, castration, etc.). When the above factors change, certain reactions occur in the animal body. The nature of stress can be different: mechanical, physical, chemical, biological, mental. Knowledge of the causes of stress, the patterns of its course, its consequences, outlined in the mentioned scientific sources, will allow rational use of the proposed ways to reduce the adverse effects of various stress factors on animals to preserve their health and high productivity.

Effect of a probiotic supplement (Bacillus subtilis) on struggling behavior, immune response, and meat quality of shackled broiler chickens exposed to preslaughter stress

This study aimed to investigate the impact of a dietary probiotic supplement on struggling behavior, immune response, and meat quality of shackled broiler chickens exposed to preslaughter stress. Two hundred and ten 1-day-old male Ross 708 broiler chicks were divided among 21 floor pens (10 chicks per pen). The pens were randomly distributed to 1 of 3 dietary treatments containing a probiotic, Bacillus subtilis, at 0 (control), 0.25 (0.25×), and 0.5 (0.5×) g/kg (n = 7). At the end of the experiment (d 35), birds were transported for a journey of 80 km to the abattoir, each crate contained 5 pen mates, 2 birds of them (2 bird per crate, total 14 birds per treatment) were randomly selected for testing. Struggling behavior measurements began after the birds had arrived at the abattoir. Serum and muscle samples (right leg and breast) were collected for immune response and meat quality parameters. The results indicated that probiotic supplemented broilers had lower breast muscle protein carbonyls and serum levels of IgM but higher breast muscle total antioxidant capacity (TAC) compared to those of controls. In addition, probiotic supplemented broilers' leg and breast muscle had higher color lightness and greater water holding capacity (WHC%) with lower cooking loss (CL) and lower pH values (P < 0.05). Probiotic supplemented broilers' breast and leg meat was also tastier (P < 0.05) compared to controls. There were no treatment effects on other measured parameters including struggling behavior, serum IgA and IgG concentrations, and breast muscle malondialdehyde (MDA) (P > 0.05). These results suggest that the probiotic supplement could be an alternative management tool for promoting broiler health and welfare by modifying immune response and meat quality.

Clove essential oil decreases antemortem stress and acts as an antioxidant in Nile tilapia

ABSTRACT This study investigated the effect of clove essential oil used prior to stunning by cranial percussion and hypothermia on Nile tilapia (Oreochromis niloticus) welfare and fillet quality. A total of 100 tilapias were divided into four groups in a 2 × 2 factorial design, exploring two stunning methods with and without clove essential oil. Behavioral responses, glucose, lactate, pH, water holding capacity, color parameters, lipid and protein oxidation, and oxidative stress were analyzed. The application of clove essential oil resulted in 100% numbing in swimming and stimulus response behaviors, and 96% in balance and eye vestibule reflex variables. Significant reductions in glucose (12.12 mg dL−1) for hypothermia group (p = 0.001) and lactate (3.36 mmol L−1) for cranial percussion (p = 0.004), 0.028 nmol lipid oxidation in hypothermia treatment (p = 0.009), and 0.134 nmol carbonyls/mg protein (p = 0.001) were observed. There was a reduction in luminosity (p = 0.010) and red intensity (p = 0.001) in the group of fish fillet that received cranial percussion, however, there was no difference in the group stunned by hypothermia. Clove essential oil demonstrates effectiveness in pre-slaughter stress mitigation, influencing the antioxidant system positively. Its usage in pre-slaughter protocols could contribute to improved fillet quality, presenting a promising alternative for enhancing tilapia welfare during slaughter.

Behavioral, physiological, and hormonal responses during pre-slaughter handling in goats: a comparison between trained and untrained handlers.

The livestock handler attitude and their handling of animals is crucial for improving animal welfare standards, minimizing stress, improving productivity and meat quality. The present study was undertaken to assess the effect of training livestock handlers on behavioral, physiological, and hormonal responses during preslaughter handling in goats. A total of 6 handlers were divided into trained (trained in basic animal handling practices, animal behavior, and animal welfare), contact trained (not trained directly but interacted and saw the working of trained handlers), and untrained groups (no formal training). The handling experiment was conducted on 18 male goats by following a crossover design. The goats were moved from lairage to slaughter point by trained, contact-trained, and untrained handlers. Various behavioral, physiological, and hormonal parameters were recorded at the lairage before handling and at the slaughter point after handling the goats. The training of livestock handlers had a significant effect on behavioral, physiological, and hormonal responses in goats. The goats handled by untrained and contacttrained handlers were recorded with intense vocalization, significant (p<0.05) increase in heart rate and blood glucose, and catecholamines (adrenaline and nor-adrenaline), thereby indicating stress and poor animal welfare. The trained handlers were observed to use visual interactions (waving of hands or objects, blocking, hand raising, etc), and lower stress responses were recorded in the goats handled by this group. The present study highlights the importance of training to livestock handlers in improving animal welfare and minimizing stress in goats during pre-slaughter stress.

Investigating the impact of preslaughter handling intensity on goats: a study on behavior, physiology, blood enzymes, and hormonal responses.

The present study evaluated the effect of preslaughter stress intensities on the behavioral, physiological, blood biochemicals, and hormonal responses in goats. Twenty-seven intact male goats (Ardi breed, 10 months of age, 27 kg liveweight) were divided into three treatment groups viz., the control (C) group, ear pulling (EP) group, and leg pulling (LP) group. Various behavioral, physiological, blood biochemical and hormonal responses were recorded before and after handling. The EP and LP goats had a higher frequency and intensity of vocalization as compared to control goats. The preslaughter handling stress intensities had a significant effect on the before and after handling values of heart rate, respiration rate, rectal temperature, and ear temperature. Further, among groups, the glucose value increased significantly upon preslaughter handling as compared to the baseline value. The LP goats had significantly higher after-handling value for lactate dehydrogenase (LDH) as compared to the before-handling value. The catecholamines (adrenaline and noradrenaline) and β-endorphin concentrations increased significantly upon preslaughter handling. The higher physiological, behavioral, blood biochemical, and hormonal response indicated higher preslaughter stress in EP and LP goats. Both levels of intensity revealed unfavorable responses in goats that may adversely affect animal welfare and meat quality. Thus, to ensure minimal adverse effects on behavior, physiology, blood enzymes, and hormonal responses, it is recommended to follow animal welfare principles when implementing preslaughter handling practices.

Antemortem Stress Regulates Postmortem Glycolysis in Muscle by Deacetylation of Pyruvate Kinase M1 at K141.

It is well known that preslaughter (antemortem) stress such as rough handling, transportation, a negative environment, physical discomfort, lack of consistent routine, and bad feed quality has a big impact on meat quality. The antemortem-induced poor meat quality is characterized by low pH, a pale and exudative appearance, and a soft texture. Previous studies indicate that antemortem stress plays a key role in regulating protein acetylation and glycolysis in postmortem (PM) muscle. However, the underlying molecular and biochemical mechanism is not clearly understood yet. In this study, we investigated the relationship between antemortem and protein acetylation and glycolysis using murine longissimus dorsi muscle isolated from ICR mice and murine muscle cell line C2C12 treated with epinephrine hydrochloride. Because adrenaline secretion increases in stressed animals, epinephrine hydrochloride was intraperitoneally injected epinephrine into mice to simulate pre-slaughter stress in this study to facilitate experimental operations and save experimental costs. Our findings demonstrated that protein acetylation in pyruvate kinase M1 (PKM1) form is significantly reduced by antemortem, and the reduced acetylation subsequently leads to an increase in PKM1 enzymatic activity which causes increased glycolysis in PM muscle. By using molecular approaches, we identified lysine 141 in PKM1 as a critical residue for acetylation. Our results in this study provide useful insight for controlling or improving meat quality in the future.

The impact of overnight lairage on meat quality and storage stability of pork loin.

Lairage, a part of the animal welfare practices, has been known to mitigate pre-slaughter stress in animals. However, research investigating the relationship between lairage and pork meat quality remains scarce. In this study, we conducted a comparative analysis of the physicochemical quality and storage stability of pork from pigs subjected to immediate slaughter (CON) and those provided with a 24 h lairage before slaughter (LRG) over a 7-day storage period. The loins from 20 castrated pigs in each group, respectively, were collected at 1, 3, 5, and 7 days and used for analysis of meat quality and storage stability, including pH, meat color, moisture, water holding capacity, drip loss, cooking loss, shear force, fatty acid composition, lipid oxidation, antioxidant activity, and electrical resistance. Overall, there were no significant differences in physicochemical meat quality parameters between CON and LRG groups. Similarly, no differences were observed in the storage stability of pork including 2-thiobarbituric acid reactive substances, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and electrical resistance. However, the proportion of unsaturated fatty acids was significantly higher in LRG compared to CON. In conclusion, 24 h lairage for castrated pigs had limited impact on meat quality and storage stability but led to an increase in the unsaturated fatty acid proportion.

Mechanical analysis and materials selection of a scissor lift system for pig transportation

Pigs can experience stressful moments during handling practices before arrival at the slaughter location, so adequate handling plays a crucial role in pig response to preslaughter stress. This work presents preliminary mechanical analysis and materials selection of a scissor lift system with the purpose of loading and unloading pigs for transport. The scissor lift offers a simple design and is frequently used as a lifting mechanism in the automotive, aerospace, advanced manufacturing, and transportation industries due to its flexibility to adapt to different uses. The design and mechanical analysis of the proposed scissor lift mechanism were performed to carry pigs ranging from 80 to 180 kg with a working height from 1 to 1.2 m to meet the first-floor height of traditional trucks. The model and the components of the system were dimensioned to ensure the well-being of the animals, avoid injuries, and reduce the stress that negatively affects meat quality. The structural analysis of the system was developed through classical analytical calculations in association with materials selection. The proposed design is apt to load and unload pigs safely and be used with different types of trucks.

Respiratory and muscular effort during pre-slaughter stress affect Nile tilapia fillet quality.

Nile Tilapia (Oreochromis niloticus) management procedures are directly linked to the final quality of the product. The aim of this study was to evaluate the effect of pre-slaughter density and different stunning methods on biochemical, respiratory and muscle injury parameters associated with quality and sensory characteristics of Nile tilapia fillets. Fish with an average weight of 762±105 g were used, first collected called the control group. The experiment was conducted in a 2 × 2 factorial scheme, with two densities (50 and 300 kg of live weight m-3) and two stunning methods thus totaling four treatments, with 15 repetitions per treatment totaling 75 fish sampled. Blood gas analysis, evaluation of biochemical parameters, analysis of meat quality and sensory analysis were carried out. For blood gas, biochemical and enzymatic parameters, the highest values were obtained for the density of 300 kg m-3 and asphyxia method: partial pressures of CO2; glucose and lactate, the highest values presented were 268.98 and 11.33 mg dL-1 respectively. As well as enzymatic activities, Creatinine kinase (CPK); Creatinine kinase isoenzyme (CKMB) showed higher values (768.93 and 1078.98 mg dL-1 respectively) in the higher density and asphyxia method. Conversely, when evaluating the quality parameters, the highest values were observed for lower density and thermonarcosis. High depuration density (300 kg m-3), combined with the asphyxiation stunning method, promotes changes in respiratory dynamics and provides greater stress, less firm fillet texture and greater weight loss due to cooking, as well as changes in creatine kinase (CK) and its CK-MB isoenzyme, demonstrating greater muscle damage. On the other hand, the density of 50 kg m-3 during pre-slaughter, combined with the method of stunning by thermonarcosis, provide a longer period of permanence in pre rigor mortis, which will result in fillets with a better sensory profile.

The effect of succinate on color stability of Bos indicus bull meat: pH-dependent effects during the 14-day aging period

Bos taurus indicus bulls are very susceptible to pre-slaughter stress, which directly impacts the decline in muscle pH, leading to darker meat. The aim was to investigate the effect of succinate and atmosphere on the color stability of Nellore (Bos taurus indicus) Longissimus lumborum steaks classified by ultimate pH (pHu): normal pHu (5.40 ≤ pHu ≤ 5.79) and high pHu (pHu ≥ 5.80). The experimental treatment systems were: (i) vacuum packaging without succinate injection, (ii) HiOx-MAP (80 % O2 + 20 % CO2), and (iii) HiOx-MAP (80 % O2 + 20 % CO2) enhanced with sodium succinate injection (pH 5.4). Steaks from all treatment systems were stored at 4 °C for 14 days and tested for instrumental color, myoglobin content, oxygen consumption (OC), metmyoglobin-reducing activity (MRA), lipid oxidation, and microbiological analysis. High and normal pHu vacuum-packaged steaks exhibited greater color stability due to higher MRA. High and normal pHu steaks packaged with HiOx-MAP or HiOx-MAP enhanced with succinate showed improved color due to lower deoxymyoglobin content (%DMb) and OC up to the eighth day of storage. Still, succinate injection promoted increased (P < 0.05) lipid oxidation in normal pHu steaks and reduced MRA after 14 days. These findings emphasize the intricate interplay between pHu and packaging systems on Bos taurus indicus meat quality. Further research in this area could contribute to a better understanding of meat color abnormalities and provide insights into potential meat preservation and enhancement strategies.

Effect of Pre-Slaughter Transport Stress on Protein S-Nitrosylation Levels of Pork during Postmortem Aging.

This study aimed to investigate the effect of pre-slaughter transport stress on the protein S-nitrosylation levels of pork during 0, 3, and 6 days of aging. Pigs (N = 16) were randomly selected and divided into two treatments: 3 h transport (transport stress, TS) and 3 h transport followed by 3 h resting (control, CON). Results showed that the TS group at 0 and 3 days presented a higher nitric oxide synthase (NOS) activity and neuronal NOS (nNOS) expression than the CON group (P < 0.05). Additionally, nNOS was not only abundantly localized in the membrane but also observed in small amounts in the cytoplasm. The immunoblot of overall S-nitrosylated protein showed that protein S-nitrosylation levels in the TS group were greater than in the CON group during postmortem aging (P < 0.05). This work can deliver novel insights into the mechanism of meat quality changes in response to pre-slaughter stress.

INDICATORS OF PRE-SLAUGHTER STRESS IN PIGS AND THEIR IMPACT ON MEAT QUALITY

The pre-slaughter handling and transport of pigs can cause stress and negatively affect the quality of meat. This article aims to investigate the impact of pre-slaughter stress on meat quality. The literature suggests that pre-slaughter stress has a significant impact on meat quality, resulting in lower meat pH, increased drip loss, and decreased meat tenderness. When the body experiences stress, cortisol triggers the liver to release glucose into the bloodstream, which provides energy for the body to respond to the stressful situation. Both serum cortisol and blood glucose levels increased post-slaughter, with a post-slaughter mean value of 7.28 µg/dl for serum cortisol (compared to the initial mean value of 6.08 µg/dl), while the blood glucose values revealed a highly catabolic state, with mean post-slaughter values of 143.24 mg/dl compared to 129.11 mg/dl mean pre-slaughter results. The study highlights a direct relationship between increased serum cortisol levels and blood glucose values when comparing the pre-and post-slaughter values with the normal reference ranges, with a highly significant correlation between the mentioned parameters (p&lt;0.01). The article also explores potential pre-slaughter indicators such as cortisol and blood glucose levels for predicting stress and meat quality in pigs. Improving pre-slaughter handling and reducing stress can lead to improved meat quality and economic benefits for the pork industry. In terms of pH24, a trust coefficient of 5.46–5.50 revealed the impact of pre-slaughter stress on meat pH, resulting in possible inferior meat in terms of quality. The study results showed a highly significant correlation between the cortisol and blood glucose values recorded post-slaughter and pH24 (p&lt;0.05), emphasizing the impact of stress on meat quality and suggesting that both serum cortisol and blood glucose values can be used as specific indicators of meat pH and ultimately meat quality.

Correlation between circulating cortisol and indicators of stress and oxidant stress during the preslaughter operations in camels

In livestock, pre-slaughter stress begins at the farm or market, continues during transport and upon arrival at the slaughterhouse, ending at slaughter. In this investigation, a survey was conducted in the slaughterhouse of Casablanca in Morocco to record the duration of the preslaughter operations and the frequency of urination in camels. Two groups of camels were constituted, the least stressed animals (Group I, n= 12) and the most stressed animals (Group II, n= 12). Group I animals had a waiting time before loading ≤ 24 h, a loading time ≤ 15 min, an unloading time ≤ 5 min, a water and food deprivation time before slaughter ≤ 24 h, a duration of accompaniment to the slaughter room ≤ 11 min and a frequency of urination during this accompaniment &lt; 3 times. Those in group II had higher duration and frequency values for the same parameters. In addition, serum stress [cortisol (COR)], oxidant stress biomarkers [malondialdehyde (MDA)] and activities of catalase (CAT) and superoxide dismutase (SOD) were analyzed in both groups, and correlations between these biomarkers and the durations of various preslaughter operations and the frequency of urination were established. The most stressed camels (G II) showed high serum concentrations of COR and MDA, and low CAT and SOD activities by comparison to the less stressed camels (G I) (P&lt;0.05). Significant correlations were recorded between COR, MDA, CAT and SOD, and the durations of various preslaughter operations, and between COR and the frequency of urination.

Pre-slaughter, slaughter and post-slaughter practices of slaughterhouse workers in Southeast, Nigeria: Animal welfare, meat quality, food safety and public health implications.

Pre-slaughter stress or the welfare condition of food-producing animals (FPAs) and the slaughter practices of slaughterhouse workers (SHWs) are critically important for the safety and quality of meats processed in slaughterhouses (SHs). Consequently, this study determined the pre-slaughter, slaughter, and post-slaughter (PSP) practices of SHWsin four SHs in Southeast, Nigeria; and discussed the impacts on meat quality and safety. The PSP practices were determined by observation method. Additionally, a structured and validated closed-ended questionnaire was used to determine the knowledge of the SHWs on: the effects of poor welfare (preslaughter stress) on the quality and safety of meats produced, carcass/meat processing practices and modes of transmission of meat-borne zoonotic pathogens during carcass/meat processing. Finally, a systematic post-mortem inspection (PMI) was conducted on cattle, pigs and goats slaughtered, and economic losses accruable from condemned carcasses/meats were estimated. Food-producing animals were transported to the SHs or held in the lairage under inhumane conditions. A pig being conveyed to one of the SHs was seen gasping for air, as it was firmly tied on motorbike at the thoracic and abdominal regions. Fatigued cattle were forcefully dragged on the ground from the lairage to the killing floor. Cattle for slaughter were restrained, held in lateral recumbency and left groaning, due to extreme discomfort, for about one hour before slaughter. Stunning was not performed. Singed pig carcasses were dragged on the ground to the washing point. Although more than 50% of the respondents knew the modes of transmission of meat-borne zoonotic pathogens during meat processing, 71.3% of the SHWs processed carcasses on bare floor, 52.2% used same bowl of water to wash multiple carcasses while 72% did not wear personal protective equipment during meat/carcass processing. Processed meats were transported to meat shops in an unsanitary conditions, using open vans and tricycles. During the PMI, diseased carcasses/meats/organs were detected in 5.7% (83/1452), 2.1% (21/1006) and 0.8% (7/924) of the cattle, pig and goat carcasses inspected, respectively. Gross lesions pathognomonic of bovine tuberculosis, contagious bovine pleuro-pneumonia, fascioliasis and porcine cysticercosis were detected. Consequently, 391,089.2 kg of diseased meat/organs valued at 978 million Naira (235, 030 USD) were condemned. There were significant associations (p < 0.05) between educational level and the use of personal protective equipment (PPE) during slaughterhouse operations and knowledge that FPAs can harbour zoonotic pathogens (p = < 0.001) transmissible during carcass processing. Similarly, significant association was observed between working experience and use of PPE; and between geographical location of the respondents and knowledge that zoonotic pathogens in animals are transmissible during carcass processing or via the food chain. The findings show that slaughter practices of SHWs have detrimental impacts on the quality and safety of meats processed for human consumption in Southeast, Nigeria. These findings underscore the need to: improve the welfare condition of slaughter-animals, mechanise abattoir operations, train and retrain the SHWs on hygienic carcass/meat processing practices. There is a need to adopt strict enforcement of food safety laws to promote meat quality, food safety and consequently promote the health of the public.

Molecular insights into quality and authentication of sheep meat from proteomics and metabolomics

Sheep meat (encompassing lamb, hogget and mutton) is an important source of animal protein in many countries, with a unique flavour and sensory profile compared to other red meats. Flavour, colour and texture are the key quality attributes contributing to consumer liking of sheep meat. Over the last decades, various factors from ‘farm to fork’, including production system (e.g., age, breed, feeding regimes, sex, pre-slaughter stress, and carcass suspension), post-mortem manipulation and processing (e.g., electrical stimulation, ageing, packaging types, and chilled and frozen storage) have been identified as influencing different aspects of sheep meat quality. However conventional meat-quality assessment tools are not able to elucidate the underlying mechanisms and pathways for quality variations. Advances in broad-based analytical techniques have offered opportunities to obtain deeper insights into the molecular changes of sheep meat which may become biomarkers for specific variations in quality traits and meat authenticity. This review provides an overview on how omics techniques, especially proteomics (including peptidomics) and metabolomics (including lipidomics and volatilomics) are applied to elucidate the variations in sheep meat quality, mainly in loin muscles, focusing on colour, texture and flavour, and as tools for authentication. SignificanceFrom this review, we observed that attempts have been made to utilise proteomics and metabolomics techniques on sheep meat products for elucidating pathways of quality variations due to various factors. For instance, the improvement of colour stability and tenderness could be associated with the changes to glycolysis, energy metabolism and endogenous antioxidant capacity. Several studies identify proteolysis as being important, but potentially conflicting for quality as the enhanced proteolysis improves tenderness and flavour, while reducing colour stability. The use of multiple analytical methods e.g., lipidomics, metabolomics, and volatilomics, detects a wider range of flavour precursors (including both water and lipid soluble compounds) that underlie the possible pathways for sheep meat flavour evolution. The technological advancement in omics (e.g., direct analysis-mass spectrometry) could make analysis of the proteins, lipids and metabolites in sheep meat routine, as well as enhance the confidence in quality determination and molecular-based assurance of meat authenticity.

On-Farm Killing as a Method to Minimize Pre-Slaughter Stress: A Qualitative Analysis from Switzerland

On-Farm Killing as a Method to Minimize Pre-Slaughter Stress: A Qualitative Analysis from Switzerland

Acute Phase Proteins as Biomarkers of Pre-Slaughter Stress in Pigs

Acute Phase Proteins as Biomarkers of Pre-Slaughter Stress in Pigs

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 AcquireXTM 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.