Meat Marbling Research Articles

Fatty acid profile, mineral content, and palatability of beef from a multibreed Angus-Brahman population.

Consumers demand meat that is both healthy and palatable, 2 attributes of meat that are affected by lipid content. Many cattle in the southern United States are Bos indicus influenced, as this improves the ability to survive and thrive in these subtropical regions. However, these animals tend to have leaner carcasses and less marbled meat products. Thus, the objective of this study was to examine the effect of percent Brahman genetics on carcass characteristics, palatability, fatty acids profile, and minerals content in LM of steers from a multibreed population ranging from 100% Angus to 100% Brahman. Breed effect was significant for birth weight (P = 0.0003), weaning weight (P < 0.0001), HCW (P < 0.0001), dressing percentage (P = 0.0008), ribeye area (P = 0.002), quality grade (P < 0.0001), and marbling score (P < 0.0001), and all these traits except dressing percentage decreased as the percentage of Brahman increased. Among palatability traits, breed group had a significant effect only on tenderness (TEND) and connective tissue (CT) scores (P < 0.0001). Least squares means decreased from Angus (5.75 ± 0.13 TEND score and 6.29 ± 0.14 CT score, respectively) to Brahman (4.84 ± 0.10 TEND score and 5.49 ± 0.11 CT score, respectively) as indicated by a significant linear effect. Breed group significantly affected the percentage of several individual fatty acids, saturated fatty acids (SFA), and polyunsaturated fatty acids (PUFA), but not monounsaturated fatty acids (MUFA). The 100% Angus group had the highest percentage of SFA at 49.92%, which was significantly higher (P < 0.05) than the SFA percentage in the 50%, 75%, and 100% Brahman breed groups. Brangus animals also had an increased SFA percentage compared with the 100% Brahman animals (P < 0.05). No significant effect was identified for the concentration of PUFA across the 6 breed groups (P = 0.14). Least squares means decreased from 100% Angus to 100% Brahman for concentration of total fat, SFA, and MUFA (g/mg meat). The concentration of magnesium (P < 0.0001), phosphorus (P = 0.06), and potassium (P = 0.06) increased as the percentage of Brahman increased. Our study shows that breed has a significant effect on the fatty acid profile of beef. Cattle with high Brahman percentage, which are characterized by lower marbled meat, will present a more favorable healthfulness profile with reduced content of SFA and MUFA but the same content of PUFA as purebred Angus animals.

CHARACTERISTICS OF UKRAINIAN GREY CATTLE BY DNA-MARKERS

CHARACTERISTICS OF UKRAINIAN GREY CATTLE BY DNA-MARKERS

Development of a flexible Computer Vision System for marbling classification

Traditional marbling meat evaluation is a tedious, repetitive, costly and time-consuming task performed by panellists. Alternatively, we have Computer Vision Systems (CVS) to mitigate these problems. However, most of CVS are restricted to specific environments, configurations or muscle types, and marbling scores are settled for a particular marbling meat standard. In this context, we developed a CVS for meat marbling grading, which is flexible to different muscle colour contrasts and grading standards. Essentially, the proposed method segments an image pre-processed by illumination normalisation and contrast enhancement, analyses visible intramuscular fat pixels and attributes a score based on a desired meat standard defined in the learning step. Learning approach is an instance-based system making use of k-Nearest Neighbours algorithm (k-NN) to attribute a score from segmentation results. The algorithm classifies the new samples based on scores assigned by panellists. We investigated the optimal number of samples for modelling, focusing on the smallest number leading to acceptable accuracy, and considering two different animal species: bovine and swine. The CVS led to accuracy values equal to 81.59% (bovine) and to 76.14% (swine), using only three samples for each marbling score.

Microarray analysis of Longissimus thoracis muscle gene expressions in vitamin A-restricted Japanese Black steers in middle fattening stage.

Vitamin A (VA) restriction in beef cattle improves meat marbling; however, the underlying molecular mechanisms remain incompletely understood. We performed microarray analysis to clarify the effect of VA restriction on Longissimus thoracis gene expressions in Japanese Black steers. Six Japanese Black steers 13-14months of age were divided into two groups: S group (n=3), which received VA supplementation, and R group (n=3), in which dietary VA intake was restricted. Steers were fattened for 7months, following which tissue samples were obtained. Extracted RNA samples were analyzed by Affymetrix Genechip Bovine Genome Array. Lists of genes highly expressed in the R and S groups were obtained. The lists were functionally interpreted using functional annotation software, DAVID. In the R and S groups, 48 and 40 genes were significantly highly expressed, respectively. The gene list of the R group included CD36, LPL, GPAM, DGAT2, and SCD and additional genes annotated 'PPAR signaling pathway,' 'lipid biosynthesis' and 'mitochondrion,' whereas that of the S group included COL1A2, FN1 and DCN and additional genes annotated 'extracellular matrix.' Changes in the expression of these genes are possibly involved in marbling improvement in beef cattle by VA restriction.

Validation of blood vitamin A concentrations in cattle: comparison of a new cow-side test (iCheck\u2122 FLUORO) with high-performance liquid chromatography (HPLC)

BackgroundPlasma concentration of retinol is an accepted indicator to assess the vitamin A (retinol) status in cattle. However, the determination of vitamin A requires a time consuming multi-step procedure, which needs specific equipment to perform extraction, centrifugation or saponification prior to high-performance liquid chromatography (HPLC).MethodsThe concentrations of retinol in whole blood (n = 10), plasma (n = 132) and serum (n = 61) were measured by a new rapid cow-side test (iCheck™ FLUORO) and compared with those by HPLC in two independent laboratories in Germany (DE) and Japan (JP).ResultsRetinol concentrations in plasma ranged from 0.033 to 0.532 mg/L, and in serum from 0.043 to 0.360 mg/L (HPLC method). No significant differences in retinol levels were observed between the new rapid cow-side test and HPLC performed in different laboratories (HPLC vs. iCheck™ FLUORO: 0.320 ± 0.047 mg/L vs. 0.333 ± 0.044 mg/L, and 0.240 ± 0.096 mg/L vs. 0.241 ± 0.069 mg/L, lab DE and lab JP, respectively). A similar comparability was observed when whole blood was used (HPLC vs. iCheck™ FLUORO: 0.353 ± 0.084 mg/L vs. 0.341 ± 0.064 mg/L). Results showed a good agreement between both methods based on correlation coefficients of r2 = 0.87 (P < 0.001) and Bland-Altman blots revealed no significant bias for all comparison.ConclusionsWith the new rapid cow-side test (iCheck™ FLUORO) retinol concentrations in cattle can be reliably assessed within a few minutes and directly in the barn using even whole blood without the necessity of prior centrifugation. The ease of the application of the new rapid cow-side test and its portability can improve the diagnostic of vitamin A status and will help to control vitamin A supplementation in specific vitamin A feeding regimes such as used to optimize health status in calves or meat marbling in Japanese Black cattle.

RESEARCHING OF MEAT AND FAT COLOUR AND MARBLING IN BEEF

The studies of meat and fat colour and marbling in Longissimus dorsi of different cattle — beef-producing (Aberdeen-Angus,Herefordbreeds) and dual-purpose (Simmental, Black-and-white breeds) — allowed to define groups by the colour values according to Lab international colour model. Measurements were performed 24 hours post-mortem between 12th and 13th ribs. It was found that different ranges of meat colour differed primarily in L* (lightness) and a* (redness) values, while b* (yellowness) values did not significantly differ. The highest differentiation between ranges of fat colour was noted in b* values, whereas L* and a* slightly differed. Moreover, visual assessment of beef marbling by four grades (small, moderate, good, and rich) and instrumental (microstructural) analysis using a computer image analysis system were carried out. The morphometric study of marbling was conducted in accordance with the principles of system quantitative analysis. To perform quantitative measurements, object analysis parameters (area) were specified. Both automatic and manual measurements of specified parameters were used. The study of Longissimus dorsi marbling established high agreement between visual and instrumental evaluations of marbling.

Desempenho, características da carcaça e qualidade da carne de novilhos cruzados Hereford-Angus alimentados com silagem de grão úmido de sorgo

RESUMO Objetivou-se avaliar três tipos de silagem de grão úmido de sorgo (alto tanino, baixo tanino e branco), na forma de silagem de grão úmido, combinados com duas formas de fornecimento da ração (volumoso e concentrado fornecidos de forma separada ou misturada), sobre o consumo de matéria seca, evolução do peso vivo, ganho de peso médio diário, conversão alimentar e principais características de carcaça (área de olho de lombo, espessura de gordura subcutânea e marmorização in vivo e post mortem) e carne (cor, maciez e pH) de novilhos cruzados Hereford-Angus. Foram utilizados 48 bovinos machos, castrados, cruzados Hereford-Angus, com idade média de 20 meses, divididos em blocos casualizados, em fatorial 3 × 2. A regressão do ganho de peso de cada tratamento foi comparada utilizando-se contrastes ortogonais. Para consumo de matéria seca relativo, houve efeito do tipo de sorgo (P=0,002) e forma de fornecimento da ração (P=0,0005). A forma de fornecimento da ração pode interferir sobre o consumo de matéria seca absoluto e peso vivo médio (P=0,0001). Para a conversão alimentar foi observado efeito do tipo de sorgo (P=0,04. Observou-se efeito da forma de fornecimento da ração para a marmorização (P=0,04) post mortem. Não houve efeito do tipo de sorgo e da forma de fornecimento da ração sobre as características de carcaça e pesos dos cortes cárneos. O fornecimento do volumoso separado do concentrado na alimentação de bovinos confinados é viável do ponto de vista operacional e nutricional.

The adipokine Chemerin induces lipolysis and adipogenesis in bovine intramuscular adipocytes.

The adipokine Chemerin is reported to regulate adipogenesis and glucose homeostasis in vivo and in 3T3-L1 cells. Our team is focused on the role of Chemerin in metabolism and intramuscular adipocyte differentiation because intramuscular fat is the basic material for the formation of marbling in livestock and poultry meat. In this study, bovine intramuscular mature adipocytes were cultured in medium with Chemerin, and the process of lipolysis of mature adipocytes and the adipogenesis of de-differentiated preadipocytes were investigated. The results showed that Chemerin induced significant lipolytic metabolism in intramuscular mature adipocytes, indicated by increased levels of glycerol, FFA, and up-regulated expression of the lipolysis critical factors HSL, LPL, and leptin. Meanwhile, the expressions of adipogenic key factors PPARγ, C/EBPα, and A-FABP were decreased by Chemerin during lipolysis or dedifferentiation in mature adipocytes. The de-differentiated preadipocytes could re-differentiate into mature adipocytes. Intriguingly, the formation of cells' lipid droplets was promoted by Chemerin during preadipocyte differentiation. In addition, mRNA and protein expressions of PPARγ, C/EBPα, and A-FABP were up-regulated by Chemerin during preadipocytes differentiation. These results suggest that Chemerin promotes lipolysis in mature adipocytes and induces adipogenesis during preadipocyte re-differentiation, further indicating a dual role for Chemerin in the deposition of intramuscular fat in ruminant animals.

Effect of replacement of de-hulled barley with water-soaked barley in corn–soybean meal-based diet on growth performance, blood characteristics, and meat quality in finishing pigs

ABSTRACTA total of 144 crossbred pigs [(Yorkshire Landrace) × Duroc] with an average initial body weight (BW) of 61.7 kg were used to assess the effect of replacement of de-hulled barley (DB) with water soaked barley (WB) in corn-soybean meal-based diet on growth performance, blood characteristics, and meat quality in finishing pigs according to their BW and sex (12 replicates per treatment and 4 pigs per pen). The dietary treatments were: DB, basal diet containing 5% DB; WB1, basal diet + 5% WB (0–8 weeks of feeding); WB2, basal diet + 5% WB (4–8 weeks of feeding). At the end of week 4, the IgG concentration (p<.05) was higher in WB1 than DB and WB2. At the end of week 8, lymphocyte percent was higher (p<.05) in DB than WB1 whereas IgG concentration was higher in WB1 and WB2 than DB. The sensory evaluation of colour scored higher (p<.05) in WB1 and meat marbling scored higher (p<.05) in WB2 than in DB. A higher (p<.05) yellowness and drip loss (day 1 and day 5) was observed in DB than in WB1. In conclusion, replacement of DB with WB had a positive impact on blood characteristics and meat quality of finishing pigs.

Sequence analysis of the S1PR1 gene in river buffalo.

Recent developments in methodologies for genomic analyses have enabled a significant advance in understanding of the river buffalo genome. The S1PR1 gene has been mapped to buffalo chromosome 6 and bovine chromosome 3; this gene is of interest as it is a candidate for marbling in meat, an important economic trait. Here, we performed next generation sequencing in a buffalo BAC DNA clone and obtained a 54.5-kb sequence encompassing the entire buffalo S1PR1 gene as well as the 27 kb upstream region and the 22 kb downstream region. The gene had a total length of 4716 bp, including three exons and two introns; exons 1 and 2 were classified as non-protein-coding. In comparison with homologues from other species, the structural organization of buffalo S1PR1 was closest to that of the goat and in both species exon 2 of the gene was non-protein-coding. One hundred and nine repetitive elements were found within the buffalo gene and its boundary regions, with 50 SINE repeats being the most abundant. Alignment of S1PR1 sequences from the Murrah and Mediterranean breeds revealed two nucleotide substitutions (g.1176C>G and g.2740T>C), which represent potential SNPs that could be used in further studies of buffalo genetic structure.

Growth performance, carcass characteristics and meat quality of West African dwarf rams fed diets supplemented with water-washed neem fruit and/or yeast

This study was conducted to determine the growth performance, carcass characteristics and meat quality of rams fed diets containing water-washed neem (Azadirachta indica) fruits with or without baker’s yeast (Saccharomyces cerevisiae) supplementation. Twelve West African Dwarf (WAD) rams (19.88±3.37kg) were assigned to one of three dietary groups with 4 animals per group in a complete randomized design. Each group received a total mixed ration with one of the following: YS: (5.0g of yeast per animal per day); NF: (5.0% water-washed neem fruit inclusion in the diet) and YS/NF: (5.0% water-washed neem fruit inclusion in the diet and 5.0g of yeast per animal per day). The animals were fed at 5% of their body weight. At the end of the 56 days feeding trial, three animals per treatment were slaughtered after being starved for 16 hours and evaluated for carcass characteristics and meat quality. Average daily weight gain, average daily feed intake and feed efficiency were significantly (P&lt;0.05) higher in YS/NF compared to other treatments. Ribeye area was higher (P&lt;0.05) in NF than YS. The dressing percentage, percentage of neck, brisket, leg and meat were not significantly (P&gt;0.05) affected by the treatments. Water-washed neem fruits significantly (P&lt;0.05) increased the percentage of flank and rack. The proportion of bone was similar in YS and YS/NF but significantly (P&lt;0.05) higher than NF. Meat-bone ratio was similar in YS and YS/NF but significantly (P&lt;0.05) lower than NF. Significant (P&lt;0.05) reduction was observed in the proportion of fat. No significant (P&gt;0.05) difference was observed in the proportion of meat in all the treatments. There were no significant (P&lt;0.05) differences in meat marbling, cold loss and thermal shortening across the treatments except thermal loss which was lowest in NF. Cold shortening was similar in NF and YS/NF but higher (P&lt;0.05) than YS. Water holding capacity was similar in YS and YS/NF but higher than NF. NF, though similar to YS was on the overall more acceptable (P&lt;0.05) than YS/NF. The treatments did not significantly (P&gt;0.05) affect the DM, CP and ash content of the meat. However, ether extract and cholesterol components were similar in NF and YS/NF but significantly lower (P&lt;0.05) than YS. These results showed that the inclusion of water-washed neem fruit and baker’s yeast in the diet of WAD rams impacted positively on growth performance, carcass characteristics and meat quality of rams without any negative effect except for low water holding capacity which may influence the type of meat product such meat can be used for.Key words: Yeast, water-washed neem fruit, performance, carcass characteristics, meat qualities, West African Dwarf ram.

Marbling Analysis for Evaluating Meat Quality: Methods and Techniques

AbstractMarbling is one of the most important traits determining the quality of meat, and the richness of marbling is often considered by consumers as the primary factor when buying meat in view of its contribution to sensory characteristics of meat. In the market, there has been a constant demand for meat products with an assured degree of marbling. Conventionally, marbling of meat is assessed by visual appraisal or chemical analysis, which has the disadvantages of being subjective and time‐consuming. In order to improve the detection accuracy and production efficiency, a variety of modern instrumental techniques, including spectroscopic techniques, imaging techniques, and hyperspectral imaging, have been developed for marbling analysis. This paper gives a comprehensive overview on the recent advances in marbling analysis. What's more, the advantages, limitations and some perspectives on the future trends of these techniques are also presented.

Estimation of intramuscular level of marbling among Whiteheaded Mutton Sheep lambs

The aim of this work was to develop a non-invasive method to estimate the degree of the intramuscular fat in the Whiteheaded Mutton Sheep lambs by means of the USG technology and the neural image analysis. The classification process was based on the muscles USG images acquired on the hot carcass just post slaughter in three scanning points of 63 lamb carcasses: the longissimus muscle – over the last rib and the 3rd lumbar vertebrae, and the leg (musculus semimembranosus). The total of 568 USG images were obtained. The image characteristics were used to learn the artificial neural networks to recognize and classify the level of marbling in lamb meat. From among different tested neural networks, the PNN (Probabilistic Neural Network) type with the structure 13-404-5-1 was found to have the best classifying capability.

Influence of production system in local and conventional pig breeds on stress indicators at slaughter, muscle and meat traits and pork eating quality

Sensory quality of pork is a complex phenotype determined by interactions between genetic and environmental factors. This study aimed at describing the respective influences of breed and production system on the development of pork quality. Plasma stress indicators and Longissimus muscle (LM) composition, physicochemical and sensory quality traits were determined in two contrasted breeds – the conventional Large White (LW, n=40) and the French local Basque (B, n=60). Pigs were reared in either a conventional (C; n=20 per breed), alternative (A; sawdust bedding and outdoor area, n=20 per breed) or extensive system (E; free-range, n=20 B). All the pigs from A and C systems were slaughtered at the same slaughterhouse, whereas B pigs from the E system were slaughtered at a local commercial abattoir. Major breed differences were found for almost all traits under study. LM from B pigs exhibited higher lipid, lower water and collagen concentrations, as well as lower collagen thermal solubility (P<0.001). Although plasma stress indicators at slaughter did not differ between breeds, except lower (P<0.05) lactate levels in B pigs, they exhibited higher LM pH1 and pHu values, and lower meat lightness, hue angle, water (drip, thawing and cooking) losses, glycolytic potential and shear force. Sensory analyses highlighted higher redness, marbling, tenderness, juiciness and flavour scores (P<0.01) of meat from B compared with LW pigs. Within both LW and B breeds, compared with C, the A system did not (P>0.05) influence plasma stress indicators, LM chemical composition and physicochemical or sensory traits of pork. In contrast, within the B pigs, the E system affected the meat quality more. Lower plasma cortisol levels (P<0.05), but higher plasma lactate, creatine kinase and lactate dehydrogenase activities, and more skin lesions (P<0.05), indicating higher muscular activity during pre-slaughter handling, were found in pigs produced in the E compared with the C system. E pigs exhibited higher meat pH1 and pHu values and shear force (P<0.01) and exhibited lower lightness, hue angle and drip and thawing losses (P<0.01) compared with the C pigs, whereas LM lipid, protein or collagen concentrations were not affected. Regarding sensory traits, the E system produced redder meat, but did not impact the eating quality of pork. Altogether, this study demonstrates that differences in meat quality between B and LW breeds can be modulated by extensive pig production system.

Molecular Characterization, Expression Profile, and Association Study with Meat Quality Traits of Porcine PFKM Gene

Glycolytic potential is a hot aspect to meat quality research in recent years. Phosphofructokinase, muscle type (PFKM), is a key regulatory enzyme used to catalyze the irreversible conversion of fructose-6-phosphate to fructose-1,6-bisphosphate in glycolysis. The present study was designed to investigate the association of PFKM SNP and meat quality traits in pigs. In this study, the 2,864-bp full-length cDNA sequence of the porcine PFKM gene was obtained, which contained 30 bp of 5' UTR, 2,343 bp of coding region, and 491 bp of 3' UTR. The porcine PFKM mRNA was predominantly expressed in skeletal muscle and heart. One single nucleotide polymorphism (SNP) T129C in exon 13 of PFKM gene was detected, with its allele frequencies significantly different between Chinese indigenous pig breed and Western pig breeds. The SNP was significantly associated with meat color value (m. biceps femoris), meat marbling (m. longissimus dorsi), meat marbling (m. biceps femoris), intramuscular fat (m. longissimus dorsi) (P<0.01), and water moisture (m. longissimus dorsi) in the Large White×Meishan F2 population. These results laid a foundation for further investigations on the detailed physiological function of porcine PFKM gene.

Win–win strategies for high beef quality, consumer satisfaction, and farm efficiency, low environmental impacts and improved animal welfare

Meat quality includes intrinsic qualities (the characteristics of the product itself) and extrinsic qualities (e.g. animal health and welfare, environmental impacts, price). There is still a high level of variability in beef palatability, which induces consumer dissatisfaction. We also observe a general trend towards an increasing importance of healthiness and safety (intrinsic) and environmental issues and animal welfare (extrinsic). Most grading systems describe carcasses using only animal traits (e.g. weight, conformation, fatness, animal age and sex). In North American and Asian countries, emphasis has been put on maturity and marbling. The European system is mainly based on yield estimation. The Meat Standards Australia grading scheme, which predicts beef palatability for each cut, proved to be effective in predicting beef palatability in many other countries. Some genetic markers are available to improve beef quality. In addition, gene and protein expression profiling of the bovine muscle revealed that the expression level of many genes and the abundance of many proteins may be potential indicators of muscle mass, tenderness, flavour or marbling of meat. The integration of all these parameters is likely to predict better beef palatability. The integration of extrinsic qualities in the prediction model increases the difficulty of achieving a global evaluation of overall meat quality. For instance, with respect to environmental issues, each feeding system has its own advantages and disadvantages. Despite this, win–win strategies have been identified. For example, animals that were less stressed at slaughter also produced more tender meat, and in some studies the most economically efficient farms had the lowest environmental impact. In other cases, there are trade-offs among and between intrinsic and extrinsic qualities. In any case, the combination of the different integrative approaches appears promising to improve the prediction of overall beef quality. A relevant combination of indicators related to sensory and nutritional quality, social and environmental considerations (such as e.g. carbon footprint, animal welfare, grassland biodiversity, rural development) and economic efficiency (income of farmers and of other stakeholders of the supply chain, etc.) will allow the prediction of the overall quality of beef mainly for consumers but also for any stakeholder in the supply chain.

Differential expression and effect of the porcine ANGPTL4 gene on intramuscular fat.

In a previous study, we investigated differences in gene expression in backfat between Meishan and Large White pigs and their F1 hybrids, Large White x Meishan, and Meishan x Large White pigs. One potential differentially expressed sequence tag from the mRNA differential display was a homolog of the human angiopoietin-like 4 (ANGPTL4) gene, which encodes a protein that is secreted by both liver and white adipose tissues and can inhibit lipoprotein lipase activity and stimulate white adipose tissue lipolysis. Here, ANGPTL4 mRNA was found to be upregulated in the backfat of Large White compared with that in the Meishan pigs and the F1 hybrids, Meishan x Large White and Large White x Meishan, whereas expression was lowest both in the longissimus dorsi and the heart, as shown by the tissue distribution profile. Only one mutation, a G/A transition located in the third intron, was found. The ANGPTL4 G/A polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) showed a significant effect on intramuscular fat (IMF), water moisture of the longissimus dorsi, meat marbling of the longissimus dorsi, and pH of the longissimus dorsi (P < 0.05). This site seemed to be significantly (P < 0.05) additive in its actions on IMF, water moisture, and pH, whereas it showed significant dominance in its action on meat marbling (P < 0.05). This locus can be potentially considered as a marker for IMF improvement.

Performance, carcass and meat quality of ewes supplemented with magnesium oxide

The objective of this study was to evaluate the performance, the carcass and meat characteristics of ewes supplemented with magnesium oxide. Eighteen 6-year-old Santa Ines ewes were used in a completely randomized experimental design, where three levels of supplementation (0.0, 0.1 and 0.2% magnesium oxide in the concentrate) were tested, with six replicates. Final weight, weight gain, feed intake and feed conversion were not affected by levels of magnesium supplementation. Hot and cold carcass weights showed linear increasing and quadratic responses, respectively, according to supplementation with magnesium. Carcass measurements such as length, depth, and measures of arm and leg were not affected by supplementation. Depth and width of the longissimus muscle and rib-eye area were not affected; however, marbling and ether extract increased linearly with supplementation. Water loss and color were not affected. Lipid oxidation and shear force were not affected by supplementation, while the myofibrillar fragmentation index showed a quadratic regression. There was a linear decrease in pH with magnesium supplementation. Supplementation with magnesium can improve carcass and meat pH, but can act negatively by increasing the amount of marbling and ether extract of meat.

CARACTERÍSTICAS DE CARCAÇA E RECEITA INDUSTRIAL COM CORTES PRIMÁRIOS DA CARCAÇA DE MACHOS NELORE ABATIDOS COM DIFERENTES PESOS

The objective of this study was to evaluate the commercial cuts income and to study the carcass characteristics of non-castrated Nellore males slaughtered at different weights. Forty Nellore males with initial average weight of 350 kg were used. The animals were divided into four groups: animals with 0 and two teeth, with carcass weight up to238,0 kg (young and light carcass); 2-teeth animals with carcass weight ranging from 238,1 to 258,0 kg (young and medium carcass); 2-teeth animals with carcass weight above 258 kg (young and heavy carcass) and animals with four or six teeth, regardless of carcass weight (adults). After 84 days of feedlot, the animals were slaughtered in a commercial abattoir. There was no difference for carcass fat characteristics and meat marbling, as well as for commercial cuts percentages, hot carcass weight and yield. Income analysis showed that, depending on the wholesale price differences of the primary cuts of the carcass, studies on cattle breeding should seek to increase the conformation and hindquarter percentage, provided they meet the minimum finishing degree required by the abattoirs. KEYWORDS: commercial cuts; fatness level; industrial break-even point; non-castrated males; slaughter weight.

Association of a single nucleotide polymorphism in the akirin 2 gene with economically important traits in Korean native cattle

The akirin 2 gene, located on chromosome 9 in cattle, was previously reported to be associated with nuclear factor-kappa B (NF-κB), involved in immune reactions and marbling of meat. To determine whether a single nucleotide polymorphism (SNP) in akirin 2 is associated with economically important traits of Korean native cattle, the c.*188G>A SNP DNA marker in the 3'-UTR region of akirin 2 was analyzed for its association with carcass weight, longissimus muscle area and marbling. The c.*188G>A SNP was genotyped by polymerase chain reaction restriction fragment length polymorphism, and the frequency of the AA, AG, and GG genotypes were 6.82%, 71.29% and 21.88% respectively. This SNP was significantly associated with longissimus muscle area (Bonferroni corrected P<0.05), and marbling score (Bonferroni corrected P<0.01). These results suggest that the c.*188G>A SNP of akirin 2 might be useful as a DNA marker for longissimus muscle area and marbling scores in Korean native cattle.