Association of blood glucose, blood lactate, serum cortisol levels, muscle metabolites, muscle fiber type composition, and pork quality traits

Type 2 diabetes mellitus related sarcopenia: a type of muscle loss distinct from sarcopenia and disuse muscle atrophy

Muscle loss is a significant health concern, particularly with the increasing trend of population aging, and sarcopenia has emerged as a common pathological process of muscle loss in the elderly. Currently, there has been significant progress in the research on sarcopenia, including in-depth analysis of the mechanisms underlying sarcopenia caused by aging and the development of corresponding diagnostic criteria, forming a relatively complete system. However, as research on sarcopenia progresses, the concept of secondary sarcopenia has also been proposed. Due to the incomplete understanding of muscle loss caused by chronic diseases, there are various limitations in epidemiological, basic, and clinical research. As a result, a comprehensive concept and diagnostic system have not yet been established, which greatly hinders the prevention and treatment of the disease. This review focuses on Type 2 Diabetes Mellitus (T2DM)-related sarcopenia, comparing its similarities and differences with sarcopenia and disuse muscle atrophy. The review show significant differences between the three muscle-related issues in terms of pathological changes, epidemiology and clinical manifestations, etiology, and preventive and therapeutic strategies. Unlike sarcopenia, T2DM-related sarcopenia is characterized by a reduction in type I fibers, and it differs from disuse muscle atrophy as well. The mechanism involving insulin resistance, inflammatory status, and oxidative stress remains unclear. Therefore, future research should further explore the etiology, disease progression, and prognosis of T2DM-related sarcopenia, and develop targeted diagnostic criteria and effective preventive and therapeutic strategies to better address the muscle-related issues faced by T2DM patients and improve their quality of life and overall health.

Effects of Muscle Type and Aging on Glycolysis and Physicochemical Quality Properties of Bactrian camel (Camelus bactrianus) Meat

Poor tenderness of camel meat has seriously hampered the development of the camel meat industry. This study investigated the effects of muscle fiber composition and ageing time on meat quality, glycolytic potential, and glycolysis-related enzyme activities. Muscle samples of the longissimus thoracis (LT), psoas major (PM), and semitendinosus (ST) were collected from eight 8-10 year old Sonid Bactrian camels (females). Muscle fiber composition was examined by ATPase staining and immunohistochemistry. Meat quality indexes, glycolytic potential, and activities of major glycolytic enzymes were examined at 4 °C aging for 1, 6, 24, 72, and 120 h. The results showed that LT was mainly composed of type IIb muscle fibers, whereas PM and ST were mainly composed of type I muscle fibers. The PCR results of the myosin heavy chain (MyHC) were consistent with the ATPase staining results. During aging, the shear force of LT muscle was always greater than that of PM and ST, and its glycolysis was the strongest; type IIa, IIb, and IIx muscle fibers were positively correlated with muscle shear force and glycolysis rate, and type I muscle fibers were significantly and negatively correlated with the activities of the key enzymes of glycolysis within 6 h. The results showed that the muscle fibers of LT muscle had the greatest glycolysis capacity. These results suggest that an excessive type IIb muscle fiber number percentage and area in camel meat accelerated the glycolysis process, but seriously affected the sensory profile of the camel meat. The results of this study provide directions for the camel industry when addressing the poor tenderness of camel meat.

Host genetics and gut microbiota jointly regulate blood biochemical indicators in chickens

Blood biochemical indicators play a crucial role in assessing an individual's overall health status and metabolic function. In this study, we measured five blood biochemical indicators, including total cholesterol (CHOL), low-density lipoprotein cholesterol (LDL-CH), triglycerides (TG), high-density lipoprotein cholesterol (HDL-CH), and blood glucose (BG), as well as 19 growth traits of 206 male chickens. By integrating host whole-genome information and 16S rRNA sequencing of the duodenum, jejunum, ileum, cecum, and feces microbiota, we assessed the contributions of host genetics and gut microbiota to blood biochemical indicators and their interrelationships. Our results demonstrated significant negative phenotypic and genetic correlations (r =  - 0.20 ~  - 0.67) between CHOL and LDL-CH with growth traits such as body weight, abdominal fat content, muscle content, and shin circumference. The results of heritability and microbiability indicated that blood biochemical indicators were jointly regulated by host genetics and gut microbiota. Notably, the heritability of HDL-CH was estimated to be 0.24, while the jejunal microbiability for BG and TG reached 0.45 and 0.23. Furthermore, by conducting genome-wide association study (GWAS) with the single-nucleotide polymorphism (SNPs), insertion/deletion (indels), and structural variation (SV), we identified RAP2C, member of the RAS oncogene family (RAP2C), dedicator of cytokinesis 11 (DOCK11), neurotensin (NTS) and BOP1 ribosomal biogenesis factor (BOP1) as regulators of HDL-CH, and glycerophosphodiester phosphodiesterase domain containing 5 (GDPD5), dihydrodiol dehydrogenase (DHDH), and potassium voltage-gated channel interacting protein 1 (KCNIP1) as candidate genes of BG. Moreover, our findings suggest that cecal RF39 and Clostridia_UCG_014 may be linked to the regulation of CHOL, and jejunal Streptococcaceae may be involved in the regulation of TG. Additionally, microbial GWAS results indicated that the presence of gut microbiota was under host genetic regulation. Our findings provide valuable insights into the complex interaction between host genetics and microbiota in shaping the blood biochemical profile of chickens. KEY POINTS: • Multiple candidate genes were identified for the regulation of CHOL, HDL-CH, and BG. • RF39, Clostridia_UCG_014, and Streptococcaceae were implicated in CHOL and TG modulation. • The composition of gut microbiota is influenced by host genetics.

Stress levels of mangalita, large white, and pietrain pigs reared in different housing systems in south eastern Europe

ABSTRACT Cortisol is a steroid hormone that regulates a wide range of vital processes throughout the body, including metabolism and the immune response. It also has a very important role in helping the body respond to stress. Numerous studies have been conducted around the world to compare the development rates of pigs raised indoors to those raised outdoors, but the results have been ambiguous and, in many cases, conflicting. The objective of this study was to determine the effects of various housing systems (indoors with no free access to outdoor runs or indoors with free access to outdoor runs) on stress levels and slaughter value in growing-finishing pigs.

Comprehensive Analysis of Long Noncoding RNA Modified by m6A Methylation in Oxidative and Glycolytic Skeletal Muscles

N⁶-methyladenosine (m⁶A) is the most common modification in eukaryotic RNAs. Accumulating evidence shows m⁶A methylation plays vital roles in various biological processes, including muscle and fat differentiation. However, there is a lack of research on lncRNAs’ m⁶A modification in regulating pig muscle-fiber-type conversion. In this study, we identified novel and differentially expressed lncRNAs in oxidative and glycolytic skeletal muscles through RNA-seq, and further reported the m⁶A-methylation patterns of lncRNAs via MeRIP-seq. We found that most lncRNAs have one m⁶A peak, and the m⁶A peaks were preferentially enriched in the last exon of the lncRNAs. Interestingly, we found that lncRNAs’ m⁶A levels were positively correlated with their expression homeostasis and levels. Furthermore, we performed conjoint analysis of MeRIP-seq and RNA-seq data and obtained 305 differentially expressed and differentially m⁶A-modified lncRNAs (dme-lncRNAs). Through QTL enrichment analysis of dme-lncRNAs and PPI analysis for their cis-genes, we finally identified seven key m⁶A-modified lncRNAs that may play a potential role in muscle-fiber-type conversion. Notably, inhibition of one of the key lncRNAs, MSTRG.14200.1, delayed satellite cell differentiation and stimulated fast-to-slow muscle-fiber conversion. Our study comprehensively analyzed m⁶A modifications on lncRNAs in oxidative and glycolytic skeletal muscles and provided new targets for the study of pig muscle-fiber-type conversion.

The effect of transportation and pre-slaughter detention on quality of pig meat

            This research aimed to determine the influence of stress of various etiologies in pigs caused by transportation and pre-slaughter conditions on meat quality. For this purpose, pigs were divided into 11 groups within two meat processing enterprises, depending on the duration of transportation (short, long without breaks and long with breaks) and the conditions of keeping animals before slaughter. Also, within the two groups were created two subgroups with pigs of different breeds. A total of 156 pigs were studied. Blood was collected from all pigs to determine cortisol and lactate levels, and a sample of meat from the longest back muscle. The pH of the meat was determined at different stages of its maturation, and the weight loss of the sample was determined. As a result of the research, it was found that the highest quality pork was obtained from pigs that experienced lower levels of stress before slaughter. Keeping pigs for 10 – 14 hours before slaughter without access to water and food resulted in higher stress levels, which were probably expressed in higher blood concentrations of cortisol and lactate. Pigs’ access to food and water during pre-slaughter retention allows for high-quality meat by reducing the influence of stress. Pigs’ access to water before pre-slaughter does not affect the stress level but positively affects the loss of meat weight during maturation. The higher the concentration of lactate in pigs’ blood, the faster the pH of the meat decreases after slaughter, which negatively affects its quality and moisture retention. If there is a long-term transport of pigs, there is no rest stop that can significantly reduce stress levels in pigs. Duration of transportation of pigs does not correlate with stress levels, as the conditions before slaughter content.

Applications of Biosensors for Meat Quality Evaluations

The aim of this study was to apply biosensors in the assessment of meat quality. The research was carried out on 20 samples of the Longissimus muscle obtained from pork of Polish Landrace and Polish Large White hybrids of fattening pigs. In the samples, 48 h after slaughter pH values, color parameters in the CIE system (L* a* b*), the volume of natural drip loss and intramuscular fat content were measured. The commercially available biosensor Accutrend Plus was used to measure glucose, triglycerides and lactic acid in meat juice. Significant (p ≤ 0.05) relationships between glucose, triglycerides, lactic acid levels and pork quality characteristics, i.e., pH (r = -0.62; r = -0.78; r = -0.68 respectively), natural drip loss and (r = 0.57; r = 0.58; r = 0.49), color parameters as L*, a* and b* (r = from 0.47 to 0.79) were demonstrated. The study showed a negative correlation between the intramuscular fat content and acidification of muscle tissue (r = -0.49), and a positive one with the brightness of color (r = 0.46). The results of the canonical analysis show that the measurement of all three metabolites in muscle juice allows the evaluation of the technological quality of meat with an accuracy of 86.54% (Rc = 0.93, p < 0.01).

Hierarchical clustering as a tool to develop a classification scheme for rabbit meat quality

<p>This study aimed to characterise the quality of meat from commercially-raised rabbits. Animals came from five different producers and were  laughtered in three different plants under provincial or federal inspection jurisdiction. Animal behaviour evaluated by scan sampling prior to feed withdrawal (FW) and transport, as well as blood lactate concentration at exsanguination, did not raise concerns with respect to stress. Stomach pH was higher (<em>P</em>=0.047) when the FW time was short (≤13.5 h), at a mean value of 2.23. All pH values measured 1 h post-mortem from the Biceps femoris (BF) and almost all (97.6%) from the Longissimus lumborum (LL) were higher than 6. Values for ultimate pH measured 24 h postmortem(pH_u) ranged from 5.80 to 6.83 and from 5.70 to 6.70 for BF and LL muscles, respectively. The maximum meat drip loss recorded was 2.6%, while cooking loss reached 30%. Meat lightness (L*) and colour intensity (C*) for the long FW times (≥23 h) were no different from those with short and intermediate (15.5 to 17.3 h) FW times. However, these colour parameters were higher for the short FW time class compared to the intermediate FW time class (<em>P</em>&lt;0.02). A hierarchical cluster analysis based on pH_u, cooking loss and lightness (L*) from 200 rabbit loins was performed. Of the four clusters created, clusters 1 and 2 had the best and second-best meat quality, respectively. Clusters 3 and 4 had the lowest meat quality and presented DFD-like (dark, firm and dry) characteristics. Meat did not exhibit PSE-like (pale, soft, exudative) characteristics, even for the slaughter lot with the minimum mean pH_u. Of the eight slaughter lots evaluated, more than 50% of the meat from three of them fell into clusters 3 and 4; all three were in the intermediate FW time class. Overall, the quality of rabbit meat analysed was acceptable for commercial use, but rather variable. This suggests that there are factors within the value chain that are not yet fully controlled and require further investigation.</p>

LncRNA-FKBP1C regulates muscle fiber type switching by affecting the stability of MYH1B

Long non-coding RNAs (lncRNAs) are well-known to participate in a variety of important regulatory processes in myogenesis. In our previous RNA-seq study (accession number GSE58755), we found that lncRNA-FKBP1C was differentially expressed between White Recessive Rock (WRR) and Xinghua (XH) chicken. Here, we have further demonstrated that lncRNA-FKBP1C interacted directly with MYH1B by biotinylated RNA pull-down assay and RNA immunoprecipitation (RIP). Protein stability and degradation experiments identified that lncRNA-FKBP1C enhanced the protein stability of MYH1B. Overexpression of lncRNA-FKBP1C inhibited myoblasts proliferation, promoted myoblasts differentiation, and participated in the formation of skeletal muscle fibers. LncRNA-FKBP1C could downregulate the fast muscle genes and upregulate slow muscle genes. Conversely, its interference promoted cell proliferation, repressed cell differentiation, and drove the transformation of slow-twitch muscle fibers to fast-twitch muscle fibers. Similar results were observed after knockdown of the MYH1B gene, but the difference was that the MYH1B gene had no effects on fast muscle fibers. In short, these data demonstrate that lncRNA-FKBP1C could bound with MYH1B and enhance its protein stability, thus affecting proliferation, differentiation of myoblasts and conversion of skeletal muscle fiber types.

Physical Activity Effects on Blood Parameters, Growth, Carcass, and Meat and Fat Composition of Portuguese Alentejano Pigs

Simple Summary

Outdoor farming systems are associated with health, animal welfare, sustainability, and food security, making them highly desirable for consumers. In this trial, it was possible to confirm that pig physical activity, a major factor in the traditional and extensive production systems of the Alentejano pig, influences animal welfare and the results of biochemical and zootechnical parameters. In this perspective, breeding pig breeds that perform spontaneous physical activity has greater advantages for producers, as pigs can reach the same slaughter weight in less time and with lower feed costs than animals reared in individual pens. Based on these results, the negative impacts that system intensification (with the consequent reduction in the vital space of each animal and the physical activity performed) may have on animal welfare, animal performance and on the quality of the meat obtained, should be considered.

Abstract

This study evaluated the effects of physical activity on blood, growth, carcass, and meat quality of finishing Alentejano (AL) pigs. Pigs, reared from ~87 to 160 kg in individual pens (no exercise area, NE group, n = 9) or in an outdoor park (with exercise area, WE group, n = 9), were fed commercial diets (85% ad libitum). WE pigs were in a park (~400 m²) with a feeding area separated from the drinking area with an automatic waterer, forcing pigs to walk at least 800 m daily. Blood samples were obtained during the trial (weeks 2, 11, and 18) and at slaughter. The left-side carcass was submitted to commercial cuts, and samples from loin, tenderloin, and dorsal subcutaneous fat (DSF) were analyzed. Plasma urea in WE pigs was higher in weeks 2 and 11, while cholesterol, LDL-cholesterol, cholesterol to HDL-cholesterol and LDL- to HDL-cholesterol ratios, and cortisol were lower in weeks 11 and 18. Final weight and average daily gain were higher and feed conversion ratio lower in WE pigs. DSF thickness and carcass weight were higher in WE pigs, leading to higher carcass yield. Finally, loin and tenderloin from WE pigs presented higher total protein content. These data show that allowing physical activity affects metabolism, growth, and carcass and meat quality of AL pigs.

Effects of marketable ages on meat quality through fiber characteristics in the goose

Goose meat is increasingly popular among consumers because of its good quality. The fiber characteristics have been well demonstrated to be key contributing factors of meat quality, and the marketable ages are also closely related to meat quality. However, little is known about the effect of different marketable ages on the quality of goose meat through its fiber characteristics. Here, fiber characteristics of Yangzhou geese of different marketable ages (70, 90, and 120 d) and their effect on meat quality were investigated. The results showed that only fast-twitch fibers were present in breast muscle, irrespective of age, and that few slow-twitch fibers could be identified in leg muscle, especially in gastrocnemius and extensor digitorum longus. Fiber diameter in breast muscle increased rapidly from age 70 d to 90 d, from 19.88 to 26.27 μm, and remained stable for 90 d thereafter. The diameter and cross-sectional area of muscle fiber continue to grow with day increasing in leg muscle. In addition, we measured the proximate composition and physical properties at different ages. Among the 3 marketable ages investigated, the 120-day-old geese had higher intramuscular fat and protein content, as well as lower moisture content, both in breast and leg meat. Greater lightness and pressing loss, with lower redness and shear force, were observed in the breast and leg meat of 70-day-old geese when compared with 90- or 120-day-old geese. Taken together, although older marketable age hardly affected muscle fiber type in geese, it would contribute to larger muscle fiber area, higher intramuscular fat and protein content, as well as redder and chewier meat. As a result, the reasonable marketable age should be taken into account to improve quality in goose meat production, and the marketable age of 90 or 120 d was recommended and it could potentially improve meat quality in goose meat production.

Dietary supplementation with Moringa oleifera and mulberry leaf affects pork quality from finishing pigs

Moringa oleifera and Morus alba leaves are nutritious non-traditional feed ingredients containing bioactive substances. This study was to evaluate the potential application of dietary Moringa and Morus leaf powder on the growth traits, carcass characteristics and meat quality of finishing pigs. Moringa did not alter growth performance or carcass characteristics, but it decreased meat b* value, increased MyHCIIa and decreased MyHCIIx mRNA levels, and increased CP and concentrations of Ala, Thr, Ile, Lys and Pro in longissimus thoracis. Morus increased final BW, ADFI and ADG, decreased F/G ratio, improved slaughter weight, carcass weight, carcass yield and meat a* value, and decreased shear force, drip loss, MyHCIIx and MyHCIIb mRNA levels, and increased MyHCI and MyHCIIa mRNA levels. Morus also increased CP, Glu, Gly, Ala, Arg, Ile, Phe, Pro, Ser, Tyr and Asp, and C16:1, C18:1n9c, C20:4n6, C18:3n3, C20:3n3, C22:1n9 and n-3 PUFA, but decreased C12:0 and C16:0. In summary, Morus improved the parameters and held great potential as an unconventional feed crop.

Abate halal com e sem insensibilização em ovinos: implicações sobre o bem-estar animal e a eficiência da sangria

RESUMO O objetivo deste estudo foi avaliar as implicações sobre o bem-estar animal e a eficiência da sangria no abate halal com e sem insensibilização em ovinos. Foram avaliados 102 ovinos, em abate comercial, separados randomicamente pelo peso em dois grupos: com insensibilização (CI) e sem insensibilização (SI). Verificou-se que os animais sem insensibilização apresentaram sinais de endireitamento e vocalização após 20 segundos da degola. Houve diferença significativa para hemácias (P<0,01), hemoglobina (P<0,01), leucócitos totais (P<0,001), bem como para os biomarcadores de estresse, como CK (P<0,01) e lactato (P<0,001). Apesar de não apresentarem diferença estatística significativa, o LDH e o cortisol ficaram acima dos valores basais em ambos os grupos. Não foram observadas alterações séricas para glicose e AST. Houve diferença estatística significativa para eficiência da sangria (P<0,01). Os resultados demonstraram que houve estresse no abate halal com e sem insensibilização e melhor eficiência da sangria em animais não insensibilizados.

Pork meat quality after exposure to low (0.5 Gy) dose of gamma radiation

Farm animals in the immediate vicinity of damaged nuclear facilities (Chernobyl, Fukushima), may be affected by an external radiation dose and a radiation dose from internal contamination. In the experiment, pigs weighing 30 kg were exposed to a full body irradiation (60Co) at a dose of 0.5 Gy. Samples from longissimus dorsi muscles at the last rib and semimembranosus muscles were collected. No significant differences of monitored meat colour indicators L*, a*, b*, C*, ΔE*, pH value, (45 min and 24 h post mortem) lactic acid concentration, water content and fat content (24 h post mortem) and drip loss indicators (24 and 48 h post mortem between the experimental and control group (10 and 10 pigs, respectively) were observed. If there is no internal contamination, and external radiation dose does not exceed 0.5 Gy, pigs from the affected area may be used for slaughter purposes. The results show that oxidative stress resulting from exposure to this dose of ionizing radiation does not affect the meat quality.

Butyrate promotes slow-twitch myofiber formation and mitochondrial biogenesis in finishing pigs via inducing specific microRNAs and PGC-1α expression1

The present study aimed to investigate the influence of dietary butyrate supplementation on muscle fiber-type composition and mitochondrial biogenesis of finishing pigs, and the underlying mechanisms. Thirty-two LY (Landrace × Yorkshire) growing pigs with BW of 64.9 ± 5.7 kg were randomly allotted to either control (basal diet) or butyrate diets (0.3% butyrate sodium). Compared with the control group, diet supplemented with butyrate tended to increase average daily gain (P < 0.10). Pigs fed butyrate diet had higher intramuscular fat content, marbling score and pH24 h, and lower shear force and L*24 h in longissimus thoracis (LT) muscle than that fed control diet (P < 0.05). Interestingly, supplemented with butyrate increased (P < 0.05) the mRNA level of myosin heavy chain I (MyHC-I) and the percentage of slow-fibers, and decreased (P < 0.05) the mRNA level of MyHC-IIb in LT muscle. Meanwhile, pigs in butyrate group had an increase in mitochondrial DNA (mtDNA) copy number and the mRNA levels of mtDNA-encoded genes (P < 0.05). Moreover, feeding butyrate diet increased PGC-1α (PPAR γ coactivator 1α) level, decreased miR-133a-3p level and increased its target gene level (TEAD1, TEA domain transcription factor 1), increased miR-208b and miR-499-5p levels and decreased their target genes levels (Sp3 and Sox6, specificity protein 3 and SRY-box containing gene 6; P < 0.05) in the LT muscle. Collectively, these findings suggested that butyrate promoted slow-twitch myofiber formation and mitochondrial biogenesis, and the molecular mechanism may be via upgrading specific microRNAs and PGC-1α expression, finally improving meat quality.

MicroRNA-152 Promotes Slow-Twitch Myofiber Formation via Targeting Uncoupling Protein-3 Gene

The differences of pork quality characteristics among different pig breeds mainly came from the differences in myofiber type compositions. Growing evidence indicated the key role of miRNAs in myofiber specification. In the present study, we found that miR-152 is more abundant in the slow-twitch myofiber-enriched muscles. However, its role in myofiber type transformation and myogenesis is largely unknown. Overexpression of miR-152 in porcine myotubes promoted the formation of slow-twitch myofibers and myogenesis. While, inhibition of miR-152 expression showed the opposite effect to miR-152 mimics transfection. The luciferase reporter analysis confirmed that miR-152 straightly targets the 3'-untranslated region (3'-UTR) of uncoupling protein 3 (UCP3) to cause its post-transcriptional inhibition in the protein level. The knockdown of UCP3 by siRNA showed the similar effect of miR-152 on myofiber type transition. Furthermore, the rescue experiment in the porcine myotube transfected with miR-152 mimics or/and UCP3 overexpression plasmid with or without the 3'UTR revealed that UCP3 mediates the action of miR-152 in slow-twitch myofiber formation. Taken together, our findings proposed a novel molecular mechanism through which miR-152 epigenetically regulates meat quality via promoting slow-twitch myofiber formation and skeletal myogenesis.

Mirrors Improve Rabbit Natural Behavior in a Free-Range Breeding System

The aim of this research was to evaluate the possible usefulness of mirrors in improving rabbit behavior in a free-range breeding system. Three groups (each consisting of nine replicates of three animals) were compared: isolated, isolated with mirrors and separated by a wire mesh (possible visual and olfactory contacts). Rabbits allowed to have a visual and olfactory contact showed a significantly higher expression of important natural behaviors (olfactory investigation, gnawing, alertness, stretching, locomotion) compared to the isolated rabbits (with or without mirrors); while rabbits in the mirror group showed higher allo-grooming activity than those isolated and no different locomotion activity than those separated by wire mesh. Thus, mirrors seemed to be able to modify the behavioral repertoire of isolated rabbits by acting on social perception in rabbits reared in small groups in a free-range system. Nevertheless, despite it being advisable to use a combination of different indicators in order to assess the stress level of an animal, the accuracy of serum cortisol, as well as of some secondary stress markers assay, appeared to be limited in this type of breeding.

Blood lactate and rectal temperature can predict exit velocity of beef feedlot steers

Interest in beef cattle temperament has increased due to growing consumer awareness of animal welfare and increased concern for handler safety. Temperament measures are based on behavioral responses to a perceived stressor. Subjective chute scoring has been used to give a numeric value to temperament; however, the subjectivity and variability among observers have been questioned. To deal with the perceived subjectivity and variability, other researchers have used exit velocity. Researchers have related faster exit velocities to increased cortisol and plasma lactate. The objectives of this study were to compare temperament between feedlot steers and heifers and to confirm chute side measures of temperament relationship to physiological responses to stress. Body temperature, blood and plasma lactate, serum glucose, salivary and serum cortisol concentrations were measured on Bos taurus commercial crossbred feedlot cattle (n = 197). Fast, medium, and slow classifications were developed from exit velocities. Plasma lactate was significantly different between all exit velocity classes. Exit velocity and physiological measures indicated that heifers were more excitable (faster exit velocities (P = 0.003), higher plasma lactate concentrations (P = 0.03), and cortisol concentrations (P = 0.001)). Simple correlations among these variables indicated body temperature (heifers r = 0.44, P < 0.0001; steers r = 0.45, P < .0001), plasma lactate (heifers r = 0.52, P < 0.0001; steers r = 0.63, P < 0.0001), blood lactate (heifers r = 0.53, P < 0.001; steers r = 0.59, P < 0.001), and glucose (heifers r = 0.54, P < 0.001; steers r = 0.32, P <0.003) were all related to exit velocity. Cortisol measures were not correlated to exit velocity in steers but were in heifers. Linear models constructed and evaluated using the Akaike information criterion indicated that blood lactate in combination with rectal temperature were strong candidates to predict exit velocity. Using the discriminate function analysis, the model correctly categorized fast and slow classifications 69.23% and 61.54%, respectively, indicating that in combination measures of body temperature and blood lactate can potentially increase accuracy of temperament identification or replace exit velocity as a measure of temperament. The plasma lactate and rectal temperature have the potential to become strong objective measures to augment or replace exit velocity.

Investigation of chemical composition of meat using spatially off-set Raman spectroscopy

Spatially off-set Raman spectroscopy (SORS) offers non-invasive chemical characterisation of the sub-surface of various biological tissues as it permits the assessment of diffusely scattering samples at depths of several orders of magnitude deeper than conventional Raman spectroscopy. Chemicals such as glycogen, glucose, lactate and cortisol are predictors of meat quality, however detection of these chemicals is limited to the surface of meat using conventional Raman spectroscopy as their concentration is higher within the tissue. Here, we have used SORS to detect spectral bands for glycogen, lactate, glucose and cortisol beneath the surface of meat tissue by spiking. To our knowledge, this is the first report on this method for potential application in meat quality analysis. We further validate our SORS spectral results using chemometric analysis to determine chemical-specific spectral characteristics suitable for chemical identification. The chemometric analysis clearly shows distinction of spiked metabolites into four distinct groups, even for such chemically similar compounds as glucose, glycogen and lactate.

Impact of space allowance on performance traits, brain neurotransmitters and blood antioxidant activity of New Zealand White rabbits

The objective of this trial was to investigate the effect of space allowance on performance, welfare-related parameters and the levels of brain neurotransmitters in growing male rabbits. In a cage housing system, a total of 96 weaned rabbits were accommodated on three space allowance conditions (S₁ = 1425 cm²/rabbit; S₂ = 850 cm²/rabbit; S₃ = 625 cm²/rabbit), with 8 replicate cages per each group. Rabbits in the S₁ and S₂ groups showed better daily feed intake and feed conversion ratio compared with the high stocking density group (p = 0.004 and 0.018, respectively). Compared to the highest stocking density group (S₃), rabbits in the S₁ and S₂ groups showed significantly lower serum cortisol, MDA and GSSH level (p = 0.026, 0.018 and 0.009, respectively). The concentration of dopamine in brain tissues was significantly decreased in the S₃ group compared with other experimental groups (P = 0.001). However, there was no significant effect of space allowance on the brain AChE level (P = 0.277). Brain serotonin and GABA levels showed a significant decrease in rabbits reared with a limited space allowance (S₃) compared with S₁ and S₂ groups (P = 0.001 and 0.038, respectively). The level of brain MDA was significantly increased in the S₃ group compared with the S₁ group (P = 0.006). However, there were no detectable differences in the brain ATP level in rabbits reared with different space allowance (P = 0.693). In conclusion, the current study indicates that the 850 cm²/rabbit stocking density has resulted in a better feed intake, and welfare-related conditions compared with the 625 cm²/rabbit. Furthermore, the limited space allowance may impair the most important brain neurotransmitters in male rabbits.

Traditional halal slaughter without stunning versus slaughter with electrical stunning of sheep (Ovis aries)

Thirty Nellore crossbred male sheep (Ovis aries) were divided into two groups of 15 animals each and subjected to either pre-slaughter electrical stunning followed by slaughter (ST) or traditional halal slaughter without stunning (NST) to investigate the changes in blood biochemical parameters, meat quality and proteomic profile. Higher (P < .05) pH, water holding capacity and Warner-Bratzler shear force were observed in meat from stunned sheep. Quantitative proteomic approach using DIGE was employed to find a panel of protein markers that could differentiate ST and NST muscle proteome. Comparison of muscle proteome of ST and NST samples by 2D-DIGE and MALDI-TOF/TOF MS analysis revealed 46 significant (P < .05) differentially expressed proteins. Our analysis revealed changes in the abundance of proteins involved in catalytic, structural, and stress related process. Current study has demonstrated variation meat quality and identified important proteins that correlate with meat texture and pre-slaughter stress in sheep that are slaughtered without and with electrical stunning.

Phytol Promotes the Formation of Slow-Twitch Muscle Fibers through PGC-1α/miRNA but Not Mitochondria Oxidation

Phytol is a side chain of chlorophyll belonging to the side-chain double terpenoid. When animals consume food rich in chlorophyll, phytol can be broken down to phytanic acid after digestion. It was reported that feeding animals with different varieties and levels of forage could significant improve pH and marbling score of steer and lamb carcasses, but the internal mechanism for this is still not reported. The marbling score and pH of muscle was mainly determined by skeletal muscle fiber type, which is due to expression of different myosin heavy-chain (MHC) isoforms. Here, we provide evidence that phytol can indeed affect the diversity of muscle fiber types both in vitro and in vivo and demonstrate that phytol can increase the expression of MHC I (p < 0.05), likely by upgrading the expression of PPARδ, PGC-1α, and related miRNAs. This fiber-type transformation process may not be caused by activated mitochondrial metabolism but by the structural changes in muscle fiber types.

Relationships among muscle fiber type composition, fiber diameter and MRF gene expression in different skeletal muscles of naturally grazing Wuzhumuqin sheep during postnatal development

The aim of this study was to determine the relationships among muscle fiber‐type composition, fiber diameter, and myogenic regulatory factor (MRF) gene expression in different skeletal muscles during development in naturally grazing Wuzhumuqin sheep. Three major muscles (i.e. the Longissimus dorsi (LD), Biceps femoris (BF) and Triceps brachii (TB)) were obtained from 20 Wuzhumuqin sheep and 20 castrated rams at each of the following ages: 1, 3, 6, 9, 12 and 18 months. Muscle fiber‐type composition and fiber diameter were measured using histochemistry and morphological analysis, and MRF gene expression levels were determined using real‐time PCR. In the LD muscle, changes in the proportion of each of different types of fiber (I, IIA and IIB) were relatively small. In the BF muscle, a higher proportion of type I and a 6.19‐fold lower proportion of type IIA fibers were observed (P < 0.05). In addition, the compositions of type I and IIA fibers continuously changed in the TB muscle (P < 0.05). Moreover, muscle diameter gradually increased throughout development (P < 0.05). Almost no significant difference was found in MRF gene expression patterns, which appeared to be relatively stable. These results suggest that changes in fiber‐type composition and increases in fiber size may be mutually interacting processes during muscle development.

Blood haematology, muscle pH and serum cortisol changes in pigs with different levels of drip loss

Objective

An experiment was conducted to study the blood haematology, muscle pH, and serum cortisol changes in pigs with different levels of drip loss.

Methods

Two groups (low and high) of 20 animals were selected from 100 pigs based on drip loss. All [Duroc× (Large White×Landrace)] pigs were slaughtered according to standard slaughtering procedures. At exsanguinations, blood samples were taken for the haematological parameters and serum cortisol analysis. The muscle samples were taken from longissimus dorsi muscle to evaluate the muscle pH and drip loss.

Results

Haematological parameters of low drip loss group showed higher content of white blood cells and monocytes than high drip loss group (p<0.05). The low drip loss group had higher muscle pH at 45 min (p<0.05) and 24 h (p<0.001) post-mortem than the high drip loss group. However, there was no significant difference in serum cortisol levels (p>0.05).

Conclusion

Drip loss is mainly affected by the muscle pH decline after slaughter and also might be affected by white blood cells and monocytes.

Development of class model based on blood biochemical parameters as a diagnostic tool of PSE meat

A fast, sensitive and effective method based on the blood biochemical parameters for the detection of PSE meat was developed in this study. A total of 200 pigs were slaughtered in the same slaughterhouse. Meat quality was evaluated by measuring pH, electrical conductivity and color at 45min, 2h and 24h after slaughtering in M. longissimus thoracis et lumborum (LD). Blood biochemical parameters were determined in blood samples collected during carcass bleeding. Principal component analysis (PCA) biplot showed that high levels of exsanguination Creatine Kinase, Lactate Dehydrogenase, Aspertate aminotransferase, blood glucose and lactate were associated with the PSE meat, and the five biochemical parameters were found to be good indicators of PSE meat Discriminant function analysis (DFA) was able to clearly identify PSE meat using the five biochemical parameters as input data, and the class model is an effective diagnostic tool in pigs which can be used to detect the PSE meat and reduce economic loss for the company.

Effects of pre-slaughter stressor and feeding preventative Chinese medicinal herbs on glycolysis and oxidative stability in pigs

A total of 64 5-month-old Pietrain pigs were randomly allocated to four treatments with four replicates per treatment according to body weight. The pigs were fed either a standard corn-soybean meal based control diet (treatments 1 and 2), the standard diet with 1% Lycium barbarum (LB) (treatment 3), or the standard diet with 1% Polygala tenuifolia Willd (PT) (treatment 4). Serum lactic acid and glucose concentrations were increased in stressed pigs (P < 0.05). Addition of the herbs in the diet had no effect on the serum lactic acid concentration, but 1% LB decreased (P < 0.05) serum glucose concentration in the stressed pigs. Pre-slaughter stress also decreased (P < 0.01) liver glycogen concentration and the decrease could be inhibited by addition of 1% LB in the diet (P > 0.05). Pre-slaughter stress increased the concentration of maleic dialdehyde (MDA) (P < 0.05) and decreased glutathione peroxidase (GSH-Px) activity in serum, while dietary 1% LB increased (P < 0.05) the activity of GSH-Px and decreased the concentration of MDA in the serum. In conclusion, pre-slaughter stress induces oxidative stress in pigs and dietary supplementation with 1% LB improves antioxidant capacity in stressed pigs before slaughtering.

Estimation of pork quality traits using exsanguination blood and postmortem muscle metabolites

The current study was designed to estimate the pork quality traits using metabolites from exsanguination blood and postmortem muscle simultaneously under the Korean standard pre- and post-slaughter conditions. A total of 111 Yorkshire (pure breed and castrated male) pigs were evaluated under the Korean standard conditions. Measurements were taken of the levels of blood glucose and lactate at exsanguination, and muscle glycogen and lactate content at 45 min and 24 h postmortem. Certain pork quality traits were also evaluated. Correlation analysis and multiple regression analysis including stepwise regression were performed. Exsanguination blood glucose and lactate levels were positively correlated with each other, negatively related to postmortem muscle glycogen content and positively associated with postmortem muscle lactate content. A rapid and extended postmortem glycolysis was associated with high levels of blood glucose and lactate, with high muscle lactate content, and with low muscle glycogen content during postmortem. In addition, these were also correlated with paler meat color and reduced water holding capacity. The results of multiple regression analyses also showed that metabolites in exsanguination blood and postmortem muscle explained variations in pork quality traits. Especially, levels of blood glucose and lactate and content of muscle glycogen at early postmortem were significantly associated with an elevated early glycolytic rate. Furthermore, muscle lactate content at 24 h postmortem alone accounted for a considerable portion of the variation in pork quality traits. Based on these results, the current study confirmed that the main factor influencing pork quality traits is the ultimate lactate content in muscle via postmortem glycolysis, and that levels of blood glucose and lactate at exsanguination and contents of muscle glycogen and lactate at postmortem can explain a large portion of the variation in pork quality even under the standard slaughter conditions.