Glycogen concentrations in bovine longissimus dorsi muscle

FHL3 promotes the formation of fast glycolytic muscle fibers by interacting with YY1 and muscle glycolytic metabolism

The proportions of the various muscle fiber types are important in the regulation of skeletal muscle metabolism, as well as animal meat production. Four-and-a-half LIM domain protein 3 (FHL3) is highly expressed in fast glycolytic muscle fibers and differentially regulates the expression of myosin heavy chain (MyHC) isoforms at the cellular level. Whether FHL3 regulates the transformation of muscle fiber types in vivo and the regulatory mechanism is unclear. In this study, muscle-specific FHL3 transgenic mice were generated by random integration, and lentivirus-mediated gene knockdown or overexpression in muscles of mice or pigs was conducted. Functional analysis showed that overexpression of FHL3 in muscles significantly increased the proportion of fast-twitch myofibers and muscle mass but decreased muscle succinate dehydrogenase (SDH) activity and whole-body oxygen consumption. Lentivirus-mediated FHL3 knockdown in muscles significantly decreased muscle mass and the proportion of fast-twitch myofibers. Mechanistically, FHL3 directly interacted with the Yin yang 1 (YY1) DNA-binding domain, repressed the binding of YY1 to the fast glycolytic MyHC2b gene regulatory region, and thereby promoted MyHC2b expression. FHL3 also competed with EZH2 to bind the repression domain of YY1 and reduced H3K27me3 enrichment in the MyHC2b regulatory region. Moreover, FHL3 overexpression reduced glucose tolerance by affecting muscle glycolytic metabolism, and its mRNA expression in muscle was positively associated with hemoglobin A1c (HbA1c) in patients with type 2 diabetes. Therefore, FHL3 is a novel potential target gene for the treatment of muscle metabolism-related diseases and improvement of animal meat production.

Residual feed intake and the inclusion of crude glycerin in the diet of feedlot-finished Nellore cattle

Context The beef market faces an increasing demand for an environmentally friendly production system with high-quality final products. The use of strategies that improve system efficiency without detriment on quality are desired for both producers and consumer. Aims This study aimed to evaluate the effects of residual feed intake (RFI) and dietary inclusion of crude glycerin on carcass and meat quality traits of feedlot-finished Nellore cattle. Methods Nellore bulls selected for growth and classified as high (n = 14) and low (n = 14) RFI, with average liveweight of 328 kg and age of 552 days were used. Bulls received a high-concentrate diet for 96 days before slaughter and were randomly allocated to two experimental diets in a 2 × 2 factorial arrangement: RFI class (low or high) and dietary inclusion (CG) or not (WCG) of crude glycerin (20% on dry-matter basis). Data were analysed with the SAS MIXED procedure considering RFI class and diet as fixed effects and selection line as a random effect. Key results There were no significant differences between RFI classes for dry-matter intake during finishing or production traits. Dry-matter intake tended to be reduced by 16% in CG bulls, without alterations in production. Dietary glycerin inclusion tended to increase the protein content in the Longissimus muscle and significantly reduced the fat content. In low-RFI bulls, shear force was higher in unaged beef, and shear force and myofibrillar fragmentation index tended to be higher in meat aged for 14 days. RFI class did not affect Longissimus muscle fatty acid profile, which was highly influenced by dietary glycerin inclusion. Bulls allocated to the CG treatment had a reduction in saturated fatty acids, an increase in odd-chain fatty acids, and a trend towards increased omega-3 fatty acids, which significantly increased the omega-3:omega-6 ratio. Conclusions The use of Nellore bulls classified as low-RFI and crude glycerin inclusion in finishing diets of Nellore cattle do not compromise production, carcass traits or beef properties. Implications This approach increases the efficiency and sustainability of the production process and improves the nutritional characteristics of beef for human consumption.

Effects of Donkeys Rearing System on Performance Indices, Carcass, and Meat Quality

This study compared growth rates, carcass, and meat quality obtained from 24 male crossbred donkey foals reared for meat production under an intensive (I) or extensive (E) feeding system. Donkeys were slaughtered at 16 months of age; the average final body weight, hot and cold carcass weight, and hot and cold dressing percentage were significantly higher (p < 0.05) in the I group. Samples of Longissimus Thoracis et Lumborum (LTL) were taken from each foal for chemical and physical analysis. Group I showed significant (p < 0.05) higher intramuscular fat, while the E group showed significantly (p < 0.05) higher protein and unsaturated fatty acids (UFA) contents, including n-3 essential fatty acids. Saturated fatty acids (SFA) and glycogen were significantly higher (p < 0.05) in the intensive system, monounsaturated fatty acids (MUFA) were significantly higher in the extensive system. The ratio PUFA/SFA was significantly higher (p < 0.05) in group E. The Thrombogenic Index (TI) was significantly higher (p < 0.05) in the I group. Meat tenderness was significantly higher (p < 0.05) in group I. The feeding system had no effect on cholesterol content and meat color characteristics. Donkeys average daily gain, carcass weight, and some meat quality parameters were significantly affected by the rearing system.

Understanding the Determination of Meat Quality Using Biochemical Characteristics of the Muscle: Stress at Slaughter and Other Missing Keys

Despite increasingly detailed knowledge of the biochemical processes involved in the determination of meat quality traits, robust models, using biochemical characteristics of the muscle to predict future meat quality, lack. The neglecting of various aspects of the model paradigm may explain this. First, preslaughter stress has a major impact on meat quality and varies according to slaughter context and individuals. Yet, it is rarely taken into account in meat quality models. Second, phenotypic similarity does not imply similarity in the underlying biological causes, and several models may be needed to explain a given phenotype. Finally, the implications of the complexity of biological systems are discussed: a homeostatic equilibrium can be reached in countless ways, involving thousands of interacting processes and molecules at different levels of the organism, changing over time and differing between animals. Consequently, even a robust model may explain a significant part, but not all of the variability between individuals.

Comparison of Carcass and Meat Quality Obtained from Mule and Donkey

The aim of this study was to compare the carcass characteristics and the chemical and physical parameters of the meat produced by 10 male crossbred donkeys and 10 male mules slaughtered at 16 ± 1 years of age. The carcass weight and dressing percentage were significantly (p < 0.05) higher in mules. Samples of the muscle Longissimus thoracis (LT) were analyzed. Donkey meat showed a higher fat content, while the glycogen content was higher in the mule LT. The total collagen content was higher in the mule LT; in this muscle, the shear force values were higher compared to the donkey LT. The lightness parameter (L*) was lower in the mule LT, while the redness index (a*) was higher in the mule LT; this muscle showed a higher content of iron, while zinc was higher in the donkey muscle LT. The donkey LT muscle showed a higher content of essential amino acids (52.2%) compared to the mule LT (50.1%). The results obtained demonstrated that the chemical and physical traits of mule and donkey meat were similar to those of other kinds of equid meat.

Modelling postmortem evolution of pH in beef M. biceps femoris under two different cooling regimes

A model based on enzyme kinetics was developed to predict differences in postmortem pH change in beef muscles as affected by cooling rate. For the calibration and validation of the model, pH and temperature measurements were conducted at different positions in M. biceps femoris following conventional carcass cooling or faster cooling of the muscle after hot boning. The glycogen conversion, and, hence, the pH fall, was observed to significantly vary with position and cooling regime but only during the initial hours of cooling. Comparison of the cooling regimes indicated that fast cooling following hot boning avoids heat shortening induced by the combined effect of high temperature and low pH.

Effects of dietary inclusion of high concentrations of crude glycerin on meat quality and fatty acid profile of feedlot fed Nellore bulls

Crude glycerin, the main by-product of biodiesel production, can replace dietary energy sources, such as corn. The objective of this study was to evaluate the inclusion of up to 30% of crude glycerin in dry matter (DM) of the total diets, and its effects on meat quality parameters of feedlot Nellore bulls. Thirty animals (227.7 ± 23.8 kg body weight; 18 months old) were housed in individual pens and fed 5 experimental diets, containing 0, 7.5, 15, 22.5 or 30% crude glycerin (DM basis). After 103 d (21 d adaptation) animals were slaughtered and the Longissimus muscle was collected. The characteristics assessed were chemical composition, fatty acid profile, cholesterol, shear force, pH, color, water-holding capacity, cooking loss and sensory properties. The increasing inclusion of crude glycerin in the diets did not affect the chemical composition of the Longissimus muscle (P > 0.10). A quadratic effect was observed when levels of crude glycerin were increased, on the concentration of pentadecanoic, palmitoleic and eicosenoic fatty acids in meat (P < 0.05), and on the activity of the delta-9 desaturase 16 and delta-9 desaturase 18 enzymes (P < 0.05). The addition of crude glycerin increased the gamma linolenic fatty acid concentration (P < 0.01), and altered the monounsaturated fatty acids in Longissimus muscle of animals (P_quad. < 0.05). Crude glycerin decreased cholesterol content in meat (P < 0.05), and promoted higher flavor score and greasy intensity perception of the meat (P < 0.01). The inclusion of up to 30% crude glycerin in Nellore cattle bulls`diets (DM basis) improves meat cholesterol and sensory attributes, such as flavor, without affecting significantly the physical traits, the main fatty acid concentrations and the chemical composition.

Manejo pré-abate de ovelhas de descarte: perdas de peso corporal, qualidade da carne e comportamento animal

Objetivou-se com este estudo conhecer o comportamento de ovelhas da raça Santa Inês em diferentes estágios fisiológicos durante o manejo pré-abate, assim como a perda de peso corporal, valores de hematócrito do sangue das mesmas e a qualidade da carne. Utilizaram-se 21 ovelhas de descarte, que foram distribuídas nos respectivos tratamentos: T1 = ovelhas que permaneceram por 60 dias em lactação com seus respectivos cordeiros e abatidas um dia após o desmame dos mesmos; T2 = ovelhas que permaneceram por 60 dias em lactação com seus respectivos cordeiros e mais um período aproximado de 30 dias sem os cordeiros e posteriormente foram abatidas; e T3 = ovelhas que permaneceram por 60 dias em confinamento e que não pariram durante o ano. O peso das ovelhas após o transporte foi menor para as do tratamento 1 em comparação às do tratamento 2. Os valores de hematócrito no sangue das ovelhas antes do transporte, após o mesmo e após o jejum dos animais no curral de espera não diferiram entre si, com valor médio de 58,50%. Concluiu-se que a qualidade da carne proveniente de ovelhas de descarte em diferentes estágios fisiológicos não é alterada pelo manejo pré-abate, quando realizado de maneira correta (evitando o estresse animal), quanto ao pH da carne.

Novel l-lactic acid biosensors based on conducting polypyrrole-block copolymer nanoparticles

Novel polypyrrole-Pluronic F127 nanoparticles with conducting and biocompatibility properties were used to construct an l-lactic acid biosensor. This method proposes great potential for the detection and evaluation of meat quality.

Glycolytic potential and activity of adenosine monophosphate kinase (AMPK), glycogen phosphorylase (GP) and glycogen debranching enzyme (GDE) in steer carcasses with normal (<5.8) or high (>5.9) 24h pH determined in M. longissimus dorsi

Muscle glycogen concentration (MGC) and lactate (LA), activity of glycogen debranching enzyme (GDE), glycogen phosphorylase (GP) and adenosine monophosphate kinase (AMPK) were determined at 0.5h (T0) and 24h (T24) post-mortem in Longissimus dorsi samples from 38 steers that produced high pH (>5.9) and normal pH (<5.8) carcasses at 24h postmortem. MGC, LA and glycolytic potential were higher (P<0.05) in normal pH carcasses. GDE activity was similar (P>0.05) in both pH categories. GP activity increased between T0 and T24 only in normal pH carcasses. AMPK activity was four times higher in normal pH v/s high pH carcasses, without changing its activity over time. Results reinforce the idea that differences in postmortem glycogenolytic/glycolytic flow in L. dorsi of steers showing normal v/s high muscle pH at 24h, could be explained not only by the higher initial MGC in normal pH carcasses, but also by a high and sustained activity of AMPK and an increased GP activity at 24h postmortem.

Regulation of post-mortem glycolysis in ruminant muscle

As a tissue, muscle has the unique ability to switch its metabolic source of ATP, the energy currency underpinning muscle function. During oxygen debt, such as that occurring immediately following the death of animals, anaerobic metabolism is initiated in an attempt to restore homeostasis within the muscle. The cascade of biochemical events that are initiated is paramount in the context of meat quality. This review revisits this reasonably well-known subject but takes a new perspective by drawing on the understanding outside the traditional discipline of meat science. Our understanding of the intrinsic regulators of glycolytic flux has improved but knowledge gaps remain. Further efforts to understand how the glycolytic enzyme kinetics are influenced by both pre- and post-slaughter factors will be beneficial in the ongoing quest to maximise fresh meat quality.

Quality of donkey meat and carcass characteristics

A study based on 15 entire donkey males was carried out to evaluate carcass quality and nutritional characteristics of meat obtained by these animals slaughtered at 15 months of age and a mean final body weight of 181kg. The meat had a low (2.02g/100g) fat content, an appreciable (22.8g/100g) protein content, and cholesterol content was 68.7mg/100g. Glycogen was also determined (0.45g/100g) within 12h of sampling. Potassium was the mineral with the highest content (343mg/100g), followed by phosphorus (212mg/100g), sodium (52mg/100g) and magnesium (24mg/100g). Donkey meat obtained from young animals can be considered a good alternative to other red meats and not only for the production salami, or other fermented meat products.

The effect of dietary treatment on meat quality and on consumer perception of sheep meat eating quality

The aim of this experiment was to test the effects of dietary treatment on sheep meat eating quality as perceived by untrained Australian consumers. Six-month-old Suffolk × Merino lambs (n = 192) were allocated to 1 of 4 nutritional treatments for 60–77 days and were fed: (i) an irrigated perennial ryegrass–clover–kikuyu sward; (ii) irrigated perennial ryegrass–clover–kikuyu pasture for 48–61 days then poor quality straw for the last 12–16 days; (iii) a mixed ration treatment consisting of a high-energy pelleted diet (40% barley grain, 30% wheat grain, 15% hay and 12% lupin grain); or (iv) irrigated pasture for 37–51 days followed by a moderate-energy pelleted diet (36% wheat grain, 35% hay and 24.5% lupin grain) for 23–26 days. The starting liveweight of lambs was 31.5–35.5 kg and the final hot carcass weight was 19–20 kg. The nutritional treatment finishing system employing straw feeding for the last 12–16 days was associated with a loss of liveweight during this period, a decreased tissue depth at the GR site and a decreased content of intramuscular fat and glycogen in muscle. Untrained Australian consumers were asked to rate samples (scale 0–100) of the M. longissimus thoracis et lumborum (LL) from lambs for tenderness, liking of flavour, juiciness and overall liking and then classify the meat as unsatisfactory, good everyday or better than everyday. Straw feeding was also associated with significantly reduced consumer scores for juiciness (P<0.05) and liking of flavour (P<0.10) with no changes in tenderness and overall liking. There was no significant difference in the consumer acceptance of the LL obtained from lambs finished on pasture v. grain-based diets. It is concluded that nutritional finishing systems should be selected to prevent animals from losing weight pre-slaughter and that decisions on pasture v. grain based feeding systems be based on the cost of production.