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Simple Summary: Nutritional and organoleptic traits are important components of the meat industry, which can affect consumers' purchasing desire and the processing of meat quality. This study evaluated the effect of feeding system on the muscle fiber characteristics, antioxidant capacity, and nutritional and organoleptic traits of goat meat. It was found that the feeding system had great effect on muscle fiber composition, antioxidant capacity, nutritional value, and organoleptic traits of goat meat, but compared with grazing on mountain range (whole area with about 40% inclination), grazing on flatland (whole area with about 0% inclination) improved the meat nutritional value and quality by altering the myofiber characteristic and antioxidative status. This study assists us in comprehending the influence of diverse feeding systems on nutritional and organoleptic traits of goat meat so as to develop more appropriate measures to retain superior quality of goat meat and provide basic data for the development of goat meat products. The objective of this study was to evaluate the effect of feeding system on muscle fiber composition, antioxidant capacity, and nutritional and organoleptic traits of goat meat. Goats that grazed on flatland (whole area with about 0% inclination, FG group) and mountain range (whole area with about 40% inclination, MG group) were selected for the analysis. The results showed that grazing on flatland increased oxidized-twitch fiber percentage, the expression of the MyHC IIa gene (p < 0.001), the activity of glutathione peroxidase (GSH-Px) (p < 0.05), total antioxidant capacity (T-AOC) (p = 0.001), and radical scavenging ability (RSA) (p < 0.05); meanwhile, the MyHC IIb gene expression (p < 0.01) and malondialdehyde (MDA) content (p = 0.001) were decreased. Feeding system affected nutritional and organoleptic traits of goat meat, and grazing on flatland increased protein content, total content of monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), pH45min, a* value, and variety of volatile flavor compounds but decreased the content of saturated fatty acid (SFA), shear force, and b* value. In addition, the key flavor substances were screened using relative odor activity value (ROAV), including hexanal, heptanal, (E)-2-octenal, octanal, nonanal, decanal, (E)-2-nonenal, and 1-octen-3-ol. Among them, 1-octen-3-ol and (E)-2-nonenal were the most contributing flavor compounds in the FG and MG groups, respectively, providing distinctive odor to goat meat. [ABSTRACT FROM AUTHOR]

Linseed as a common oil crop that has been implicated in regulating the meat quality of animals. The aim of this investigation was to establish the effects of dietary linseed supplementation on carcass traits, meat quality, muscle fiber characteristics, volatile compounds and antioxidant capacity of sheep. Twenty‐four Sunit sheep were distributed into 2 groups with different diet: control (CO) fed a standard diet and linseed (LS, 8% of extruded linseed). The results showed that linseed not only increased M. longissimus thoracis (LT) increased the loin‐eye area but also decreased pH24h, L* and shear force. Meanwhile, linseed increased mRNA expression of MyHCI and MyHCIIx and decreased in cross‐sectional area (CSA) and muscle fiber diameter. In addition, linseed altered the composition of meat volatile flavor compounds, such as Z‐10‐Pentadecen‐1‐ol, pentanal, 2‐Octenal, (E)‐, decanal, butane, and 2‐heptanone. Moreover, linseed increased total antioxidative capacity (T‐AOC) activity, the mRNA expression of glutathione peroxidase (GSH‐Px) and catalase (CAT), decreased malondialdehyde (MDA) content. Overall, the results suggest that linseed is an effective feed additive in improving meat quality and flavor. The underlying mechanisms for its effectiveness may be partly due to a change in muscle fiber characteristics and antioxidant capacity. [ABSTRACT FROM AUTHOR]

Simple Summary: This manuscript investigated the effects of different feeding regimes on antioxidant activity, meat quality, fatty acid composition, lipid oxidation, and volatile matter production in the longissimus thoracis muscle of Sunit sheep during postmortem aging. It was found that pasture-fed sheep had better oxidative stability, meat quality, and fatty acid composition. At the same time, aging affected the oxidative stability, meat quality, and fatty acid composition of sheep meat, which in turn had an impact on the flavor composition of sheep meat. Aging also eliminates the differences caused by different feeding regimes to a certain extent. The purpose of this study was to investigate the effects of feeding regimes and aging time on the meat quality of sheep and to provide meat professionals with a theoretical basis that can be applied in practical production. It also accelerated the transition from traditional grazing to indoor rearing to maintain ecological balance. The effects of different feeding regimes on antioxidant activity, meat quality, fatty acid composition, lipid oxidation, and volatile matter production in the longissimus thoracis (LT) of Sunit sheep at 0, 24, 48, 72, and 96 h postmortem were investigated. The results showed that the activity of antioxidant enzymes, tenderness, water retention, and percentage of unsaturated fatty acids were significantly higher in the pasture-fed sheep (PF) than in the concentrate-fed sheep (CF) (p < 0.05). During postmortem aging, antioxidant activity, water retention, and the proportion of unsaturated fatty acids decreased in the PF and CF (p < 0.05), while malondialdehyde (MDA) content, the proportion of saturated fatty acids, and the content of flavor substances resulting from fat oxidation increased. After 24 h of LT muscle aging, the pH and shear force of the meat started to increase and the color stabilized. The differences between shear force values and lipid volatile flavor substance content of sheep meat under different feeding regimes disappeared with increasing aging time. PF had better oxidative stability and fatty acid composition. Postmortem aging changed the oxidative stability of sheep meat, thus affecting meat quality and fatty acid composition and consequently meat flavor composition, while aging also eliminated to some extent the differences caused by feeding regimes. [ABSTRACT FROM AUTHOR]

This study investigated the effects of probiotics on growth performance, meat quality, muscle fiber characteristics, volatile compounds, and antioxidant capacity in lambs. A total of 24 Sunit lambs were randomly allocated into two groups, each consisting of three replicates of four lambs. Throughout the experiment period, the lambs were fed with based diet (CON) and 10 g probiotics/d supplemented diet (PRO). Compared with the CON group, the number of lactic acid bacteria in fecal samples of PRO group was significantly increased (p <.05) and the coliforms were significantly decreased (p <.05). Dietary probiotics supplementation decreased pH24h, L*, and shear force (p <.05). The muscle fibers were switched from type IIB to type I, with a decrease in the mean cross‐sectional area (CSA) (p <.05) of longissimus thoracis (LT) muscle. Also, probiotics altered the composition of meat volatile flavor compounds, such as nonanal, undecanal, 1‐pentanol, 1‐hexanol, and 2,3‐octanedione. In addition, probiotics increased the total antioxidative capacity (T‐AOC) and catalase (CAT) activity of LT muscle, while it decreased superoxide dismutase (SOD) activity (p <.05). Overall, these results indicated that probiotics could be used as an effective feed additive by improving meat tenderness and flavor. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of oxidative stability variation on meat quality and flavor in biceps femoris (BF) and longissimus dorsi (LD) muscles of lambs during postmortem aging. The samples were stored at 4±1℃; the meat quality, flavor and muscle oxidative stability were measured on day 0, 1, 2, 3, and 4 of postmortem aging. The results showed that malondialdehyde (MDA) content increased in both muscle types; superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH‐Px) activities decreased, as did total antioxidative capacity (T‐AOC). LD muscle showed lower MDA content and antioxidative activity than BF muscle. Meat quality analyses indicated that aging increased the lightness (L*), redness (a*), and yellowness (b*) values of meat while improving its tenderness. Gas chromatography–mass spectrometry results showed that volatile flavor compounds were more abundant in LD muscle than in BF muscle. As the aging time extended, relative contents of aldehyde and alcohol increased in both muscles. The key flavor compounds during postmortem aging including heptanal, octanal, nonanal, and decanal were screened by relative odor activity value (ROAV), and the content of key flavor compounds showed the trend of increasing, which were usually associated with fresh green grass, nutty, and fat descriptors. In conclusion, the oxidative muscles displayed better antioxidative capacity, and postmortem aging altered the oxidative stability of lamb muscle, which affected the meat quality and flavor. Practical Application: Meat aging is an important strategy to improve the quality of various meat traits (including flavor). The results of this work could be of interest to meat professionals who will be able to apply in actual production by choosing the best aging time based on flavor and meat quality for different muscle parts. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of exercise training on muscle metabolism, fatty acid composition, carcass traits, and meat quality characteristics of Mongolian sheep. Fourteen Mongolian sheep were randomly divided into two groups (7 sheep in each) and placed in two adjacent livestock pens. One group of sheep was kept in the pen (Control [C] group) and the other group of sheep (Training [T] group) were driven away in a field to walk twice a day. The results showed a reduction in pH measured 45 min post mortem, L*, a*, and b* value, intramuscular fat, and carcass length, and an increase in the ultimate pH value and shear force in the meat of T group in comparison with that of C group (p <.050). Also, exercise training moderately affected the fatty acid composition of LT muscle. Compared with C group, the concentrations of myristoleic acid (C14:1) and stearic acid (C18:0) were increased (p <.050), while the concentrations of C20:3 n‐6, neurolic acid (C24:1), and n‐3 polyunsaturated fatty acid (PUFA) were decreased in T group (p <.050). Transcriptome analysis highlighted 621 genes differentially expressed in two groups, including 385 were up‐regulated (e.g., GLUT4 and PGC‐1α) and 236 were down‐regulated (e.g., PLIN1 and ACSL3) in T with respect to C group. Besides, considering these genes, a number of enrichment pathways related to muscle metabolic processes, involving carbohydrate metabolism, lipid metabolism, oxidation reduction process, and muscle tissue development, were highlighted. In conclusion, these results contributed to a better understanding of the possible biological and molecular processes underlying the effects of exercise training on muscle metabolism and meat quality in Mongolian sheep, and provide useful information for contributing to understand the phenotypic and functional differences in meat quality of sheep. [ABSTRACT FROM AUTHOR]

To investigate the effects of the activator of AMPK and high glucose on the differentiation of mouse SMSCs, primary SMSCs were isolated from mouse extensor digitorum longus muscle and grown to near confluence (80%). Postconfluent cells were cultured in a growth medium with different inductors: AICAR, glucose, and AICAR mixed with glucose. The specific protein expressions of SMSCs, myoblasts, adipocytes, and brown adipocytes were analyzed on days 0, 3, 5, 7, and 10. The results showed treatment with AICAR in SMSCs markedly activated AMPK phosphorylation (p <.05) and increased protein expression of Pax7 and MyoD (p <.05), high concentrations of intracellular glucose upregulated UCP‐1 protein expression and enhanced lipid accumulation (p <.05), the cowork of AICAR and glucose affected a decrease on MyoD, PPARg, and UCP‐1 expression (p <.05) and an increase on Pax7. The present study indicated that the certain energy supplements influence the direction of SMSC differentiation which may contribution on the structure of muscle and meat quality, sequentially. [ABSTRACT FROM AUTHOR]

The effects of two feeding regimens on meat quality, myosin heavy chain (MyHC) types, and key factors regulating muscle fiber type (AMP‐activated protein kinase [AMPK] and peroxisome proliferator‐activated receptor‐coactivator‐1α [PGC‐1α]) in the biceps femoris muscle of Mongolia sheep were investigated. A total of 20 Mongolia sheep were weaning for 90 days and divided into two groups (pasture group (P) and confinement group (C)) at 10.36 ± 0.35 kg of weaning weight. After weaning, sheep were pasture fed or confinement fed for 9 months. The results showed that live weights, carcass weight, intramuscular fat (IMF), and Warner–Bratzler shear force (WBSF) in P group were significantly lower (p <.05) than that in C group. Compared with P group, color evaluations with respect to L* and b* values were significantly higher (p <.05) in C group. Expression of the MyHC I gene in the P group was significantly higher, while MyHC IIa and MyHC IIb genes expression was significantly lower (p <.05) than that in C group. Also, AMPK activity and expression of AMPKα2 and PGC‐1α genes were significantly higher (p <.05) in P group compared with C group. The present study indicated that muscle fiber composition was one of the key differences leading to the differences of meat quality in different feeding regimens. AMPK, particularly AMPKα2, and PGC‐1α were considered to be two key factors regulating muscle fiber types in Mongolia sheep. The results support that AMPK activity and the expression of AMPKα2 and PGC‐1α genes may affect the composition of muscle fibers; thus, AMPK activity and the expression of AMPKα2 and PGC‐1α genes had an effect on meat quality by changed composition of muscle fibers. [ABSTRACT FROM AUTHOR]

The aim of the present work was to investigate the effects of feeding regimens (pasture vs. mixed diet) on meat quality, fatty acids, volatile compounds, and antioxidant properties in lamb meat. In total, 24 lambs were allotted into two feeding regimens at 10.23 kg live weight. Lambs were fed on pasture grass (PG group, n = 12) or mixed diet (M group, n = 12). Longissimusthoracis (LT) muscle samples from the M group had a higher intramuscular fat (IMF) (p < 0.05), pH45minvalue (p < 0.01), and ash (p < 0.05) than the PG group. In contrast, the shear force (p < 0.05), L*(p < 0.05), and b* (p < 0.001) in M group were lower than in PG group. Analyses indicated that PG group contained higher linolenic acid (C18:3n3) and docosatrienoic acid (C22:3n6) (p < 0.05) than the M group. Major volatile compounds in the muscles included hexanal, heptanal, nonanal, octanal, 1‐pentanol, 1‐hexanol, 1‐octen‐3‐ol, and 2,3‐octanedione. The levels of hexanal, nonanal, and 2,3‐octanedione were significantly lower in PG lamb muscle (p < 0.01). In contrast, 1‐pentanol and 1‐hexanol levels were higher in M lamb muscle (p < 0.01). Muscle from PG lamb exhibited higher catalase (CAT) and glutathione peroxidase (GPx) activity (p < 0.05). PG muscle also contained a higher radical‐scavenging ability (RSA; p < 0.001) and cupric‐reducing antioxidant capacity (CUPRAC; p < 0.05). Overall, the improved antioxidant status in PG muscle inhibited lipid peroxidation (aldehydes and ketones), thereby improving the meat quality. [ABSTRACT FROM AUTHOR]

This study evaluated the contributions of Clostridium butyricum on skeletal muscle development, gastrointestinal flora and meat quality of lambs. Eighteen Dorper (♂) × Small Tailed Han sheep (♀) crossed ewe lambs of similar weight (27.43 ± 1.94 kg; age, 88 ± 5 days) were divided into two dietary treatments. The control group was fed the basal diet (C group), and the probiotic group was supplemented with C. butyricum on the basis of the C group (2.5 × 108 cfu/g, 5 g/day/lamb; P group) for 90 d. The results showed that dietary C. butyricum elevated growth performance, muscle mass, muscle fiber diameter and cross-sectional area, and decreased the shear force value of meat (P < 0.05). Moreover, C. butyricum supplementation accelerated protein synthesis by regulating the gene expression of IGF-1/Akt/mTOR pathway. We identified 54 differentially expressed proteins that regulated skeletal muscle development through different mechanisms by quantitative proteomics. These proteins were associated with ubiquitin-protease, apoptosis, muscle structure, energy metabolism, heat shock, and oxidative stress. The metagenomics sequencing results showed that Petrimonas at the genus level and Prevotella brevis at the species level in the rumen, while Lachnoclostridium , Alloprevotella and Prevotella at the genus level in the feces, were significantly enriched in the P group. Also, butyric acid and valeric acid levels were elevated in both rumen and feces of the P group. Overall, our results support the idea that C. butyricum could change gastrointestinal flora, and affect skeletal muscle development and meat quality of lambs by modulating gut-muscle axis. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • Long-term physical exercise before slaughter resulted in faster muscle pH decline post-mortem and more yellow meat in Sunit sheep. • Physical exercise caused a shift of muscle fibers from oxidative to glycolytic type. • Physical exercise activated skeletal muscle satellite cells influencing the process of conversion from muscle to meat. Abstract The objective of this study was to investigate the effects of muscle exercise on meat quality characteristics and protein and gene expression of Sunit sheep. To this end, 24 Sunit sheep that had the same genetic background and had been raised on extensive pasture for their first 9 months were randomly divided into two groups (12 sheep each), which were raised separately for 3 months until slaughter. The first group of sheep was kept on pasture and allowed to move freely outdoors (M Group), whereas the other group of sheep was kept in one pen on the farm (control [C] group). After slaughter, samples of the longissimus dorsi muscle were taken to evaluate meat quality. The differences in the expression of muscle-exercise-related proteins and genes between the two groups were analyzed by Western blotting and RT-PCR techniques. The results showed reductions in the pH measured 1 h and 24 h post-mortem and in the a* value (redness) for meat colour in the longissimus dorsi muscle of the sheep in the M group in comparison with those in the C group (P < 0.01), while an increasing b* value (yellowness) for meat colour was observed in the M group sheep (P < 0.01). The greater (P < 0.05) levels of Pax7 and MyoD but not PPARγ in the M group indicated that the activated skeletal muscle satellite cells underwent myogenesis rather than adipogenesis. In addition, endurance exercise caused a shift in myosin heavy chain composition from the oxidative isoform to the glycolytic form (P < 0.01), which may have resulted in the pH decline and the colour change. In conclusion, exercise-induced activation of skeletal muscle satellite cells, which regulate the pH and colour of meat, was associated with the transformation of muscle fiber types in Sunit sheep. [ABSTRACT FROM AUTHOR]

Highlights • Feeding regimens effected gene expression of FADS1 and FADS2 in adipose tissue. • The content of n-3 PUFA, especially EPA and DHA is higher in pastured sheep. • Different tissues have variable sensibilities to feeding regimens. Abstract The present study investigated the effects of two feeding regimens on meat quality, fatty acid profile and metabolism as it relates to gene expression in Sunit sheep. Two feeding regimens were used (pasture feeding and barn feeding, PF and BF) each containing 10 Sunit sheep. Results of this study indicated that PF sheep had significantly (P < 0.05) higher L* and b* values in their muscle compared to BF sheep. Also, the fatty acid composition of longissimus dorsi muscle and subcutaneous adipose tissues differed between feeding regimens. In this respect, concentrations of palmitic acid (C16:0) in the subcutaneous adipose tissue were significantly (P < 0.05) higher in BF sheep. Pastured sheep exhibited greater concentrations of polyunsaturated fatty acids (PUFA) including: linolenic acid (C18:3) (P < 0.001), DHA (P < 0.05), EPA (P < 0.001) and CLA cis-9, trans-11(P < 0.05) in their muscle compared to BF sheep. The expression of nine candidate genes related to fatty acid metabolism were analyzed by qPCR. In longissimus dorsi muscle, expression of acetyl CoA carboxylase (ACACA; P < 0.05) was up-regulated in BF sheep. Expression of the peroxisome proliferator activated receptor (PPARγ) (P < 0.05), stearoyl CoA desaturase (SCD) (P < 0.01), fatty acid desaturase1 (FADS1) (P < 0.05) and fatty acid desaturase 2 (FADS2) (P < 0.05) were up-regulated in PF sheep. Pasture feeding also increased (P < 0.05) expression of lipoprotein lipase (LPL), PPARγ, SCD, FADS1and fatty acid elongase 5 (Elove5) in the subcutaneous adipose tissue, however, the feeding regimens did not change expression of fatty acid synthase (FASN) and carnitine palmitoyl transferase I (CPT1). The results of this study indicated that the feeding regimen could be an important tool in manipulating the fatty acid profile of animal adipose tissue by altering the gene expression of enzymes involved in fat metabolism. [ABSTRACT FROM AUTHOR]

Supplementing animal feed with probiotic additives can promote muscle production and improve meat quality. The study aimed to explore the effects of dietary probiotics supplementation on the performance, meat quality and muscle transcriptome profile in Sunit lamb. Overall, feeding probiotics significantly increased the body length, LT area, pH 24h and intramuscular fat (IMF) content, but decreased cooking loss and meat shear force compared to the control group (P <.05). A total of 651 differentially expressed genes (DEGs) were found in probiotic supplemented lambs. Pathway analysis revealed that DEGs were involved in multiple pathways related to muscle development and fat deposition, such as the ECM-receptor interactions, the MAPK signaling pathway and the FoxO signaling pathway. Therefore, dietary probiotic supplementation can improve muscle development and final meat quality in Sunit lambs by altering gene expression profiles associated with key pathways, providing unique insights into the molecular mechanisms by which dietary probiotics regulate muscle development in the lamb industry. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of muscle exercise on meat quality characteristics and protein and gene expression of Sunit sheep. To this end, 24 Sunit sheep that had the same genetic background and had been raised on extensive pasture for their first 9 months were randomly divided into two groups (12 sheep each), which were raised separately for 3 months until slaughter. The first group of sheep was kept on pasture and allowed to move freely outdoors (M Group), whereas the other group of sheep was kept in one pen on the farm (control [C] group). After slaughter, samples of the longissimus thoracis muscle were taken to evaluate meat quality. The differences in the expression of muscle-exercise-related proteins and genes between the two groups were analyzed by Western blotting and RT-PCR techniques. The results showed reductions in the pH measured 1 h and 24 h post-mortem and in the a* value (redness) for meat colour in the longissimus thoracis muscle of the sheep in the M group in comparison with those in the C group (P < 0.01), while an increasing b* value (yellowness) for meat colour was observed in the M group sheep (P < 0.01). The greater (P < 0.05) levels of Pax7 and MyoD but not PPARγ in the M group indicated that the activated skeletal muscle satellite cells underwent myogenesis rather than adipogenesis. In addition, endurance exercise caused a shift in myosin heavy chain composition from the oxidative isoform to the glycolytic form (P < 0.01), which may have resulted in the pH decline and the colour change. In conclusion, exercise-induced activation of skeletal muscle satellite cells, which regulate the pH and colour of meat, was associated with the transformation of muscle fiber types in Sunit sheep. [ABSTRACT FROM AUTHOR]