Meat Characteristics Research Articles

Transcriptome and targeted metabolome analysis of lipid profiles, nutrients compositions and volatile compounds in longissimus dorsi of different pig breeds.

Improving meat quality is important for commercial production and breeding. The molecular mechanism of intramuscular fat (IMF) deposition and meat characteristics remain further study. This study aimed to study the mechanism of IMF deposition and meat characteristics including redox potential, nutrients compositions and volatile compounds in longissimus dorsi (LD) by comparing with different pig breeds including Shanghai white (SW), Duroc x (Landrace Yorkshire) (DLY) and Laiwu (LW) pigs. Results showed that the contents of IMF, triglyceride (TG), total cholesterol (TC), and redox potential parameters were lower, while the content of MDA and activity of lactate dehydrogenase (LDH) were higher in LD of SW pigs compared with LW pigs (p<0.05). No differences were observed about these parameters between SW and DLY pigs. Also, the contents of medium-long chain fatty acids and γ-aminobutyric acid (GABA) were higher, while Asp was lower in LD of SW pigs compared with LW pigs (p<0.05). Volatile compounds results showed that 6 ketones, 4 alkenes, 11 alkanes, 2 aldehydes, 1 alcohol were increased and cholesterol was decreased in SW pigs compared with LW pigs. Transcriptome results showed that differential expressed genes involved in lipid synthesis, metabolism and transport in LD between SW and LW pigs, which were further verified by qPCR. Spearman correlation showed that HSL and Nedd4 were positively related to contents of TG and IMF, while negatively related to volatile compounds and fatty acids (p<0.05). Plin3 and Mgll were negatively related to contents of TG, IMF and cholesterol, while positively related to MDA, LDH, and volatile compounds (p<0.05). PPARA was negatively related to contents of TC and IMF, and activity of SOD, while positively related to volatile compounds (p<0.05). Our study provided new insights into potential mechanisms of IMF deposition, nutrients composition and volatile compounds of muscular tissues of different pig breeds.

Preparation and flavor characteristics of plant-based meat flavoring by mixed fermentation of multiple strains

In this study, plant-based meat flavoring was prepared by mixed fermentation and thermal reaction. Based on the changes of amino acid nitrogen, reducing sugar, and total acid during the fermentation process and combined with sensory evaluation, the optimal fermentation conditions were determined as 4 % total inoculation amount of Monascus purpureus, Actinomucor elegans, and Bacillus subtilis with an inoculation ratio of 1:1:1, and 36 h of fermentation time. The odor characterization of meat flavoring was identified by solid-phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS), aroma extract dilution analysis (AEDA), quantitative measurements, odor activity value (OAV) and aroma recombination and omission experiments. 64 volatile compounds and 28 odorants were identified. The compounds with FD ≥ 27 were precisely quantified by five-point standard calibration curve and OAVs were calculated, and those with OAV ≥ 1 were subjected to aroma recombination and omission experiments. Finally, furfuryl mercaptan, difurfuryl disulfide, 4-methyl-5-ethylthiazole, 1-octanal, and 2-acetylthiophene were determined to be the key aroma-active compounds. These compounds have been recognized as key aroma-active compounds or detected in other meats or meat flavorings. In this study, we prepared plant-based meat flavoring through mixed fermentation, and provide new ideas for the development of plant-based thermal reaction meat flavoring process.

Libyan local pigeon: Preliminary description of meat characteristics

يعد الحمام أحد أنواع الدواجن البديلة الممكنة لإنتاج اللحوم. خصائص الذبيحة في فراخ الحمام المحلي الليبي لم يتم توصيفها من قبل. تهدف هذه الدراسة إلى وصف مبدئي لخصائص ذبيحة فراخ الحمام المحلي وتركيبها الكيميائي. أجريت الدراسة على ستة فراخ من سلالة الحمام المحلية الليبية تتراوح أعمارها بين (28-40 يومًا). منعت الطيور من الطعام والشرب لمدة 12 ساعة ووزنت (الوزن الحي)، ثم ذبحت ونزع ريشها باستخدام ماء ساخن (85 درجة مئوية) و أزيلت أحشاءها الداخلية وسجل وزن الذبيحة. بلغ متوسط الوزن الحي ووزن الذبيحة المنزوعة الأحشاء 283.38 و 207.81 جرام، على التوالي. كانت نسبة التصافي 73.36٪. يمثل الصدر والرجل (الفخذ + عصا الطبال) أعلى القطعيات: 34.91٪ و 5.82٪ من وزن الذبيحة، على التوالي. كانت نسبة اللحم إلى العظم في قطعيات الصدر والفخذ والجناح والظهر 10.55 و 5.49 و 3.12 و 3.16 على التوالي. كان محتوى لحم الفراخ من الرطوبة والبروتين الخام والدهن الخام والرماد 67.01 و 21.72 و 8.78 و 1.19٪، على التوالي. بناءً على النتائج المتحصل عليها من الدراسة الحالية، يمكن أن يشكل لحم الحمام أحد أنواع لحوم الدواجن البديلة في سوق لحوم الدواجن المحلي.

Influence of age at slaughter and sex on carcass characteristics, meat quality, fatty acids, and ribonucleotides in white-tailed yellow native chickens.

This study investigated the effects of age and sex on carcass and meat characteristics of one of Thailand's major indigenous chicken breeds, the white-tailed yellow native chicken (NC). A total of 120 one-day-old NC (60 males and 60 females) were raised, and harvested at either 16, 20 or 24 weeks. The results showed that body, carcass, breast and fillet weights did not differ (P > 0.05) between 16- and 20-week-old NC, but were lower (P < 0.05) than those of 24-week-old NC. Male NC had higher (P < 0.05) body, carcass, wing, back and thigh weights than female NC. Neither sex nor age affected muscle pH, sarcomere length, redness and yellowness, guanosine monophosphate, and hypoxanthine. The interaction between age and sex was significant (P < 0.05) for %dressing, %leg, L*, C14:1, C18:1n9 and C20:4n6. Shear force was lower in 16-week-old NC (P < 0.05). The 24-week-old NC had lower (P < 0.05) C13:0, C16:0, C18:0, C18:2n6t, C20:4n6, C22:6n-3, intramuscular fat and inosine 5'-monophosphate levels and higher (P < 0.05) C18:2n6c, C18:3n-3 and C20:3n-6 levels than the 16- and 20-week-old NC. Male NC had higher (P < 0.05) C13:0-, C14:0-, C18:2n6t-, C20:3n-6- and lower inosine levels than female NC. In conclusion, these data highlight age- and sex-specific differences in carcass and meat quality of NC and provide relevant information to support consumer-oriented decisions on the production, processing and nutritional value of NC.

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.

Revealing the global mechanism related to carnosine synthesis in the pectoralis major of slow-growing Korat chickens using a proteomic approach.

This study aimed to find global mechanisms related to carnosine synthesis in slow-growing Korat chickens (KRC) using a proteomic approach. M. pectoralis major samples were collected from 10-week-old female KRC including low-carnosine (LC, 2,756.6±82.88 μg/g; n = 5) and high-carnosine (HC, 4,212.5 ±82.88 μg/g; n = 5). We identified 152 common proteins, and 8 of these proteins showed differential expression between the LC and HC groups (p<0.05). Heat shock 70 kDa protein 8, Heat shock 70 kDa protein 2, protein disulfide isomerase family A, member 6, and endoplasmic reticulum resident protein 29 were significantly involved in protein processing in the endoplasmic reticulum pathway (false discovery rate<0.05), suggesting that the pathway is related to differential carnosine concentration in the M. pectoralis major of KRC. A high concentration of carnosine in the meat is mainly involved in low abundances of Titin isoform Ch12 and Connectin and high abundances of M-protein to maintain homeostasis during muscle contraction. These consequences improve meat characteristics, which were confirmed by the principal component analysis. Carnosine synthesis may occur when muscle cells need to recover homeostasis after being interfered with carnosine synthesis precursors, leading to improved muscle function. To the best of our knowledge, this is the first study to describe in detail the global molecular mechanisms in divergent carnosine contents in meat based on the proteomic approach.

The interaction of Lactiplantibacillus plantarum and Latilatilactobacillus sakei regulated the formation of characteristic quality attributes of low-salt fermented tilapia

The regulation of quality characteristics of fermented aquatic food based on microbial metabolic interaction is a hot spot in the innovative processing of aquatic products around the world. In this study, electronic sensory system, gas phase method and liquid phase method based on mass spectrometry were used to study the effects of the interaction between Lactiplantibacillus plantarum and Latilactobacillus sakei on the quality and flavor of dry-cured tilapia. The targeted supplementation of Latilactobacillus sakei S199 can improve the texture and flavor characteristics of tilapia meat fermented by Lactiplantibacillus plantarum 550. Latilactobacillus sakei S199 can cross metabolize with Lactiplantibacillus plantarum 550 to produce more 1-Octen-3-ol, 3-methyl-1-Butanol, 1-Hexanol, 2-ethyl-1-Hexanol, (E)-2-Octen-1-ol, 2-Heptanone, 3-Octanone, 2-Pentyl-Furan, and 2,5-diethyltetrahydro-Furan, and reduce the content of Heptanal, Nonanal, and Benzaldehyde to enhance the aroma of fermented tilapia fish. The aroma intensity increased by three times, from 129.46 μg/kg to 373.02 μg/kg, white the bitterness of tilapia meat fermented by the two bacteria was reduced by half, from 231.26 μg/g to 153.65 μg/g. The interaction of Lactiplantibacillus plantarum 550 and Latilactobacillus sakei S199 promoted proteolysis and utilized the FAAs and other small molecular compounds to generate other flavor compounds. The results were helpful to understand the effect of the interaction between Lactiplantibacillus plantarum 550 and Latilactobacillus sakei S199 on the flavor formation of dry cured tilapia.

Exploring the effects of ageing on instrumental and sensory characteristics of meat from Lidia breed females: A comparative study of two commercial types

The aim of this study was to assess the influence of ageing on instrumental and sensory qualities in Longissimus thoracis et lumborum (LTL) from heifers (n = 200) and cows (n = 100) of Lidia breed. The animals were slaughtered as heifers (24–48 months) or cull cows (> 48 months). For instrumental analysis, pars Thoracis aged at 7, 14 and 28 days was used; for sensory analysis, pars Lumborum aged at 14 and 28 days was evaluated. Heifers showed redder and yellower meat (P < 0.05) and cows showed slightly higher Water Holding Capacity (WHC): Thawing Loss (TL) = P < 0.05; Drip Loss (DL) = P < 0.01; Pressure Loss (PL) = P < 0.01; Cooking Loss (CL) = P < 0.05. Ageing generated changes in meat colour, with increases in lightness (L*, linear pattern, P < 0.001) and oscillations in a* and b* (quadratic patterns; P < 0.05 and P < 0.001, respectively). Ageing affected TL (increasing, P < 0.001) and PL (decreasing, P < 0.05), and generated a significant improvement in Warner Bratzler Shear Force (WBSF) values (P < 0.001). Commercial type revealed changes in consumer panel ratings for flavour (P < 0.05), juiciness (P < 0.01), tenderness (P < 0.001) and overall acceptability (P < 0.001), with better results in these parameters for cull cows. In contrast to the usual, ageing did not affect the sensory traits. There was no significant interaction between commercial type and ageing time, except for beef flavour, which worsened with ageing (P < 0.05).

Plasma activated water effects on behavior, performance, carcass quality, biochemical changes, and histopathological alterations in quail

BackgroundPlasma-activated water (PAW) is an innovative promising technology which could be applied to improve poultry health. The current study investigated the effects of drinking water supply with PAW on quail behaviour, performance, biochemical parameters, carcass quality, intestinal microbial populations, and internal organs histopathology. A total of 54 twenty-one-day-old Japanese quail chicks were randomly allotted to three treatments provided with PAW at doses 0, 1 ml (PAW-1), and 2 ml (PAW-2) per one litter drinking water. Each treatment contained 6 replicates (3 birds/ cage; one male and two females).ResultsThe results clarified that there were no significant (P > 0.05) changes in behaviour, and performance. For the biochemical indicators, the PAW-1 group showed significantly higher serum H2O2, total protein and globulin levels compared with the other groups (P = 0.015, < 0.001, and 0.019; respectively). PAW groups had significantly lower serum creatinine and urea levels than the control (P = 0.003). For the carcass quality, the internal organs relative weight between different treatments was not changed. In contrast, there was a significant increase in the meat colour, taste, and overall acceptance scores in PAW groups compared with the control one (P = 0.013, 0.001, and < 0.001; respectively). For the intestinal microbial population, lactobacilli count was significantly higher in PAW-2 compared with the control group (P = 0.014), while there were no changes in the total bacterial count between different treatment groups. Moreover, mild histological changes were recorded in the intestine, liver, and spleen of PAW groups especially PAW-2 compared with the control one.ConclusionsPAW offered benefits, such as reducing creatine and urea levels, improving meat characteristics, and increasing lactobacilli count, all of which are crucial for sustainable quail farming. Therefore, further research is needed.

Optimization of pulsed electric fields-assisted thawing process conditions and its effect on the quality of Zhijiang duck meat

Freezing storage is a common preservation method for industrialized duck meat. However, both the frozen storage and thawing processes of meat can affect meat quality. Therefore, appropriate thawing methods are crucial for maintaining good meat quality. In this study, a pulsed electric field (PEF) was used for thawing zhijiang duck meat and the freshed duck meats were used as control. Optimization of the PEF-assisted thawing process and its effect on the quality of zhijiang duck meat were analyzed. Our data showed that the shear force in the 2 kV/cm PEF-assisted thawing group was the lowest in PEF-assisted thawing groups. The color of zhijiang duck meat in the 2 kV/cm PEF-assisted thawing group was optimal. The 2 kV/cm PEF-assisted thawing could improve the texture characteristics of zhijiang duck meat and enhance water holding capacity of zhijiang duck meat. PEF-assisted thawing could better maintain the microstructure of zhijiang duck meat. Our data showed that if the intensity or duration of PEF treatment is too high, the quality of duck meat will actually decrease. Therefore, appropriate parameters should be selected in practical applications, which will provide a reference for the application of PEF-assisted thawing on the market.

Genome-wide association studies of color characteristics of chicken meat

Genome-wide association studies of color characteristics of chicken meat

Microbiological and physicochemical evaluation of chicken cuts submitted to peracetic acid application during the slaughter

Large-scale poultry slaughter is a highly automated process, which makes cross-contamination possible during the process due to failures in the cleaning and maintenance of automatic equipment, line speed, among other control parameters. To this end, using organic acids to decontaminate poultry meat is a unique strategy for reducing foodborne illnesses. Given the above, this work investigated the application of peracetic acid (PAA) in chicken breast and thigh cuts, to (a) evaluate the effectiveness of PAA as an antimicrobial against Enterobacteriaceae and aerobic mesophilic count (b) evaluate the impact of PAA on the color, texture and cooking loss of skinless chicken breast and chicken thighs with skin. Through the Central Composite Rotational Design (CCRD) with 11 trials and 3 replicates of the central point, the best conditions variable's concentration and time of application of PAA in the cuts were determined. In cuts treated with 1500 PAA solution, a reduction of 2.90 for Enterobacteriaceae in chicken breast was possible with conditions in the central point region and a reduction of 3.65 for Enterobacteriaceae in chicken thigh, when concentrations above 1800 ppm were applied. Peracetic acid (PAA) did not influence the physicochemical characteristics of chicken meat, since it did not change the appearance of fresh meat evaluated by objective analyses (color, texture, and cooking loss), which could impact consumer preference and acceptability.

Growth Performance, Meat Quality, and Lipid Oxidation in Pigs’ Fed Diets Containing Grape Pomace

Grape pomace is a winery byproduct that is rich in polyphenols with antioxidant capacity. This study investigated the effect of 0, 5, and 10% inclusion of dehydrated grape pomace (DGP) in finishing pig diets on the growth performance, carcass traits, fatty acid profile, fresh meat quality, and fat stability of a local pig genotype. A total of 36 pigs, 18 barrows, and 18 gilts (83.23 ± 6.03 kg and 132.1 ± 5.6 days old) were allotted in a randomized block design considering the initial weight (block) within sex, with six replicates of each sex per treatment. Including DGP in the diets did not affect daily weight gain or the feed-to-gain ratio; however, daily feed intake increased linearly (p &lt; 0.05) and backfat thickness at the last rib, backfat thickness at the first sacral vertebrae, P2 backfat thickness, fat area, and the percentage of lean meat decreased linearly (p &lt; 0.05) in pigs. The inclusion of DGP in pig diets did not affect the antioxidant potential evaluated by thiobarbituric acid-reactive substances in mini hamburgers or the quality characteristics of fresh meat, except for intramuscular fat (EE). The dietary inclusion of DGP linearly increased (p &lt; 0.05) EE, saturated fatty acids, monounsaturated fatty acids, and Σω-3 and reduced the ω-6:ω-3 ratio in a linear way (p &lt; 0.05) in the loin of pigs. We concluded that it is feasible to include up to 10% of DGP in pig diets without affecting growth performance, but carcass quality may be impaired due to increased adiposity. Furthermore, meat quality can be improved by increasing intramuscular fat and ω-3 fatty acid content, but fat stability is not affected when DGP is included at up to 10% of the diet for 49 days prior to slaughter.

Effect of a microencapsulated blend of organic acids and bioactive compounds on the quality and visual appraisal of broiler meat

For 2160 broilers, were raised from 1 to 42 d of age, was evaluated the consequences of microencapsulated blend of organic acids and bioactive compounds on dietary supplementation in broilers on meat quality and consumer acceptance during 200 days. Broilers were randomly distributed in a completely randomized design with 6 treatments: Negative control (NC): basal diet; Positive control (PC): NC+ Zinc bacitracin 15%; B150: NC+150 g/t of the microencapsulated blend of organic acids and bioactive compounds; B300: NC+300 g/t of the microencapsulated blend of organic acids and bioactive compounds; B450:NC+450 g/t of the microencapsulated blend of organic acids and bioactive compounds; and B600:NC+600 g/t of the microencapsulated blend of organic acids and bioactive compounds. The poultry meat characteristics (thawing loss, cooking loss, shear force, color and microstructure of the meat), oxidative stability (lipid oxidation, antioxidant activity DPPH and ABTS) and consumer acceptance (visual appraisal and willingness to buy) were evaluated. Color parameters (L and b), thawing losses and shear force were not significantly different among the treatments (NC, PC, B150, B300, B450 and B600; p > 0.05). The highest level of a was in the PC. The cooking losses were the greatest in B600. No treatment showed changes in muscle fibers. The antioxidant activity for DPPH was higher for B600. For ABTS, B150 and B300 presented the least lipid oxidation. When evaluating consumers' visual preference, B300 had the greatest in consumer preference and B150 and B300 had the greatest purchase intention on the first day of storage. After 6 days, B300 continued to be the most preferred and B150 and B450 began to show the greatest purchase intention. The B300 treatment showed a protective effect on lipid stability and consumer preference. These results highlight the importance of using a precise additive dosage during animal production to guarantee the meat's quality and satisfy consumers’ demands.

Genome-wide association study of growth and reproductive traits based on low-coverage whole-genome sequencing in a Chubao black-head goat population

The Chubao black-head goat is a novel hybrid breed that combines the advantages of Macheng black goats, such as good reproductive performance, strong adaptability, and resistance to rough feeding, with the superior growth and meat characteristics of Boer goats. Given the substantial economic importance of growth (such as birth weight, body height, body length, and chest circumference across different growth stages) and reproductive traits (particularly average litter size after first parity), the aim of this study was to identify significant SNPs and candidate genes associated with these traits in Chubao black-head goats. Through whole-genome sequencing (with 34 goats at approximately 15× coverage and 466 goats at approximately 1× coverage), genotype imputation, and quality control, 22,665,331 SNPs were identified and subsequently used for genetic analyses. Heritability estimates indicated that growth traits exhibit moderate to high heritability (ranging from 0.297 ± 0.071 to 0.535 ± 0.118), while reproductive traits demonstrated low to moderate heritability (with a value of 0.220 ± 0.108). By performing FarmCPU-based genome-wide association studies, we identified 48 potentially significant SNPs associated with growth traits and 7 with reproductive traits. Additionally, 85 candidate genes (such as COL14A1, ZNF148, and TTC39C) linked to growth traits were identified and enriched in pathways associated with fundamental molecular biological activities such as protein deubiquitination, regulation of mRNA stability, and the MAPK signaling pathway. Furthermore, 10 candidate genes (such as SOHLH2, CCNA2, and SOX7) associated with reproductive traits were identified and enriched in pathways related to specific reproductive processes such as oocyte differentiation, endoderm formation, and progesterone-mediated oocyte maturation. Overall, these findings provide valuable preliminary insights into the molecular mechanisms underlying growth and reproductive traits in Chubao black-head goats. However, further functional validation is needed to effectively use these potential SNPs and candidate genes in improving the breeding of these traits in this breed.

Metabolomic profiles and compositional differences involved in flavor characteristics of raw breast meat from slow- and fast-growing chickens in Thailand

This study aimed to differentiate the flavor characteristics of raw chicken breast meat from Thai slow-growing breeds (NC: native chicken, and KC: Korat/crossbred chicken) and fast-growing broilers (BR: broiler chicken) by using NMR-based metabolomic approaches along with multivariate data analysis. Chemical compounds related to chicken's flavor including free amino acids (FAA), ATP and its related compounds, sugars, as well as volatile compounds (VOC), were also investigated. BR had the highest total FAAs, followed by NC and KC (P < 0.05). In contrast, the accumulations of ATP degradation products, particularly ADP and IMP, were found at higher levels in the NC and KC (P < 0.05), while the highest total reducing sugars were noted in the KC (P < 0.05). Most VOCs found in the fresh breasts were products from the degradation of lipids, especially through lipid oxidation, which was found in varied types and proportions among samples. Not only chemical compounds but varying amounts of metabolites among samples were also detected. Apart from 21 identified metabolites, Glu, Gln, and betaine were the most prevalent in all samples with VIP > 1.00. Among 19 metabolic pathways, the most important pathways (P-value < 0.05, FDR < 0.05, impact > 0.05) were discovered to differentiate the flavor of raw chicken breast meat from various breeds. These metabolic pathways included (1) Ala, Asp and Glu metabolism; (2) D-Gln and D-Glu metabolism; (3) Purine metabolism; (4) β-Ala metabolism; (5) Aminoacyl-tRNA biosynthesis; (6) Nicotinate and nicotinamide metabolism; (7) Pyrimidine metabolism. Interestingly, based on the principal component analysis plot and partial least square-discriminant analysis (R2 = 0.9804; Q2 = 0.9782), NC and KC were clustered in the same area and discriminated from BR, indicating their similar flavor characteristics and metabolic profiles. Therefore, the findings could comprehend and distinguish the flavor of chicken breast meat of slow- from fast-growing chicken breeds based on their chemical characteristics and metabolite profiles.

Effect of precursor amino acids for carnosine synthesis on breast fiber microstructures and myofiber differentiation-related gene expression in slow-growing chicken.

: The effects of carnosine synthesis on the structural and microstructural determinants of meat quality have not been studied to date. Therefore, this study aimed to investigate the effect of supplementation with carnosine synthesis precursors on the characteristics and microstructure of breast muscle fibers in slow-growing Korat chickens (KR). : Slow-growing KR were fed a non-supplemented commercial diet (control group) or a commercial diet supplemented with 1.0% β-alanine, 0.5% L-histidine, or a combination of both 1.0% β-alanine and 0.5% L-histidine. At 10 weeks, KR were slaughtered, and the breast muscle was collected. Samples were fixed and extracted to study the microstructure, fat level, and porosity of the meat using X-ray and scanning electron microscopy, and real-time polymerase chain reaction was performed to analyze the expression of genes related to myofiber differentiation. : L-histidine supplementation significantly altered myofiber diameter and muscle fiber density and compactness by regulating muscle fiber-type differentiation via carnosine synthase (CARNS1) and myocyte enhancer factor 2C (MEF2C) expression, as well as myogenic differentiation antigen (MyoD) and myogenic regulatory factor 5 (Myf5) expression. While excess L-histidine potentially stimulated CARNS1 to modify muscle fiber arrangement and tenderness in breast meat, dietary β-alanine supplementation alone or in combination with L-histidine supplementation induced a relatively less remarkable but not significant (p<0.05) effect on the breast meat characteristics studied. : Interestingly, the combination of β-alanine and L-histidine supplementation had no effect on meat microstructure, meat porosity, and fat content in comparison with the control group. Thus, this combination had the best selectivity for improving meat quality. However, further studies are required to clarify the effects of carnosine levels on meat processing.

Effects of rumen-protected fat on performance, carcass and meat characteristics, and feeding behaviour of Nellore bulls finished in intensive grazing systems

Context Beef cattle production in the tropics is based on the grazing system. Concentrate supplementation has a significant influence on carcass gain and meat quality. Additionally, the inclusion of some lipid feedstuffs, such as rumen-protected fat (RPF), can increase the net energy for weight gain, and be an alternative to increase the productive performance and carcass traits of grazing beef cattle. Aims This study evaluated the effects of RPF on performance, carcass traits and feeding behaviour of Nellore bulls in an intensive grazing system during the rainy season. Methods Twenty-four Nellore bulls (initial bodyweight of 454.0 ± 46.1 kg) were used in a randomised completed block design, based on initial bodyweight. The animals were distributed in 12 paddocks (two bulls per paddock) in a continuous grazing system and randomly assigned to one of two treatments: control (n = 6), a concentrate without added protected fat provided ad libitum, and RPF (n = 6), a concentrate with the addition of 3% protected fat (Nutricorp, Araras, São Paulo, Brazil) provided ad libitum. Statistical analysis was performed using the MIXED procedure of SAS 9.4 with paddock as the experimental unit (12 paddocks). The principal model included fixed effect of treatment and block as a random effect. For forage characteristics, the experimental period was a considered fixed effect. The study lasted 105 days, and was divided into four periods. At the end of each period, forage collections were performed, bulls were weighed and feeding behaviour was recorded. After 105 days, the bulls were slaughtered in a commercial slaughterhouse, and three 2.54-cm Longissimus dorsi steaks of each animal were collected to evaluate the colour, the chemical and physical composition, and the sensory analysis of the meat. Keys results The inclusion of RPF in the concentrate did not affect (P &gt; 0.05) the final bodyweight, average daily gain, concentrate intake and feed efficiency, but there was a tendency (P &lt; 0.07) for higher carcass weight for the bulls that received RPF. Bulls supplemented with RPF had a greater (P &lt; 0.05) average carcass gain. For meat quality, an effect (P &lt; 0.01) was observed for hue (25.32 and 27.91 for control and RPF, respectively). Conclusions The addition of 3% RPF in the concentrate ration has the potential to improve carcass traits and meat quality of beef cattle in an intensive pasture finishing system. Implications The inclusion of RPF will increase dietary energy density of grazing beef cattle with a tendency to increase carcass gain. This can be an opportunity to increase the production per animal and income of farmers.

Research note: differential heterosis of spent laying hens’ carcass characteristics and meat quality in reciprocal crosses between White Leghorn and Beijing-You chickens

Hybridization is used extensively in commercial layer production. However, heterosis for carcass performance and meat quality of spent laying hens remains unclear, especially under the trend of extended laying cycles. In this study, indigenous Beijing-You chickens (Y) and elite White Leghorn layers (W) were selected to generate purebreds (WW and YY) and reciprocal crosses (WY and YW). Data on traits including carcass compositions, meat quality, and main nutrients for breast muscle were collected when chickens fed to 100 wks of age. Results showed that body weight (BW) and dressed weight for WY and YW with positive heterosis were significantly higher than WW (P < 0.05). YW had the heaviest breast and thigh of 232.28 g and 278.48 g, respectively. The abdominal fat weight for WY and YW were greatly higher than that for WW (P > 0.05). The yields of carcass compositions, including the dressed yield, half eviscerated yield, eviscerated yield, breast yield and thigh yield, did not differ among four genetic groups (P > 0.05), except for the yield of abdominal fat. The largest heterosis differences appeared in breast weight (12.26% in YW v.s. -0.46% in WY) and abdominal fat yield (15.26% in YW v.s. 24.55% in WY). Although BW for crossbreds were similar, the specific parts of the carcass between them were different. For meat quality, WY had negative heterosis (P < 0.05) with the lowest lightness and yellowness, whereas YW had the completely opposite trend. Neither pH1h nor pH24h values had difference among purebreds and reciprocal crossbreds (P > 0.05). The drip loss and cooking loss were 4.01%-4.77% and 15.59%-21.31% respectively among four genetic groups. The main nutrients of breast, including moisture, crude protein, intramuscular fat and unsaturated fatty acid, did not differ for purebreds and crossbreds (P > 0.05), except for saturated fatty acid. In general, the crossbreds even at the later laying period still showed divergent heterosis on carcass performance and meat characteristics. In view of the heterosis, Beijing-You chickens can use as the sire line in the crossbreeding to improve carcass compositions of spent hens.

Carcass and Meat Characteristics of Cull Heifers from Different Genetic Groups Fed Diets with Different Sources of Nonprotein Nitrogen in Confinement.

The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN-(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)-in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles.