Adult Steers Research Articles

Intradiscal treatment of the cartilage endplate for improving solute transport and disc nutrition.

Poor nutrient transport through the cartilage endplate (CEP) is a key factor in the etiology of intervertebral disc degeneration and may hinder the efficacy of biologic strategies for disc regeneration. Yet, there are currently no treatments for improving nutrient transport through the CEP. In this study we tested whether intradiscal delivery of a matrix-modifying enzyme to the CEP improves solute transport into whole human and bovine discs. Ten human lumbar motion segments harvested from five fresh cadaveric spines (38-66 years old) and nine bovine coccygeal motion segments harvested from three adult steers were treated intradiscally either with collagenase enzyme or control buffer that was loaded in alginate carrier. Motion segments were then incubated for 18h at 37 °C, the bony endplates removed, and the isolated discs were compressed under static (0.2MPa) and cyclic (0.4-0.8 MPa, 0.2Hz) loads while submerged in fluorescein tracer solution (376Da; 0.1mg/ml). Fluorescein concentrations from site-matched nucleus pulposus (NP) samples were compared between discs. CEP samples from each disc were digested and assayed for sulfated glycosaminoglycan (sGAG) and collagen contents. Results showed that enzymatic treatment of the CEP dramatically enhanced small solute transport into the disc. Discs with enzyme-treated CEPs had up to 10.8-fold (human) and 14.0-fold (bovine) higher fluorescein concentration in the NP compared to site-matched locations in discs with buffer-treated CEPs (p < 0.0001). Increases in solute transport were consistent with the effects of enzymatic treatment on CEP composition, which included reductions in sGAG content of 33.5% (human) and 40% (bovine). Whole disc biomechanical behavior-namely, creep strain and disc modulus-was similar between discs with enzyme- and buffer-treated CEPs. Taken together, these findings demonstrate the potential for matrix modification of the CEP to improve the transport of small solutes into whole intact discs.

86 Effects of Hurricane-Related Prenatal Stress on Postnatal Growth and Development of Steers and Heifers in a Limited Resource Beef cow-Calf System

Abstract Cost effective growth in beef calves is necessary for productivity of limited-resource pasture-based cow-calf operations. However, pasture-based production systems are often plagued by environmental stressors such as droughts, high ambient temperatures and adverse weather events that might impede calf growth and development. Our study evaluated the effects of prenatal stressors such as hurricanes on postnatal calf growth and development. Crossbred beef calves born from the same lineage in two different years were compared: Group 1, dams experienced effects of a category 5 hurricane in their late gestation. Group 2, dams experienced no adverse environmental effects their late gestation. Body weights and condition scores were collected at weaning, yearling age, 14 -15 months age and, and 20 months of age. Blood samples were collected periodically to evaluate metabolite and hormone profiles. Data were evaluated by mixed procedures of SAS, and significance determined at P&amp;lt; 0.05. Calf body weights during the juvenile periods were less (P&amp;lt; 0.05) in both steers and heifers born to dams that experienced hurricane-related stress during late gestation compared with their normal contemporaries. However, this weight difference was not evident during adult stages. Further, although blood cortisol was not different in yearling heifers, glucose and progesterone concentrations were decreased (P&amp;lt; 0.05; P&amp;lt; 0.01, respectively) in Group 1 heifers compared with the control group. In adult steers, serum cortisol differed (P&amp;lt; 0.001) between groups (965±38 vs 1282±40.5, pg/mL for Groups 1 and 2 respectively). Indeed, Group 1 steers exhibited decreased serum cortisol concentrations at both summer and fall periods when ambient temperatures were expected to present varied stressful challenges to the animals. Thus, detrimental effects of a natural disaster such as a hurricane may impede postnatal growth and development of heifers and steers as seen in this project. Further investigation is on this phenomenon is warranted. Funded by NIFA CBG # 2021-38821-34599.

Combined transcriptome and proteome analyses reveal differences in the longissimus dorsi muscle between Kazakh cattle and Xinjiang brown cattle.

ObjectiveWith the rapid development of proteomics sequencing and RNA sequencing technology, multi-omics analysis has become a current research hotspot. Our previous study indicated that Xinjiang brown cattle have better meat quality than Kazakh cattle. In this study, Xinjiang brown cattle and Kazakh cattle were used as the research objects.MethodsProteome sequencing and RNA sequencing technology were used to analyze the proteome and transcriptome of the longissimus dorsi muscle of the two breeds of adult steers (n = 3).ResultsIn this project, 22,677 transcripts and 1,874 proteins were identified through quantitative analysis of the transcriptome and proteome. By comparing the identified transcriptome and proteome, we found that 1,737 genes were identified at both the transcriptome and proteome levels. The results of the study revealed 12 differentially expressed genes and proteins: troponin I1, crystallin alpha B, cysteine, and glycine rich protein 3, phosphotriesterase-related, myosin-binding protein H, glutathione s-transferase mu 3, myosin light chain 3, nidogen 2, dihydropyrimidinase like 2, glutamate-oxaloacetic transaminase 1, receptor accessory protein 5, and aspartoacylase. We performed functional enrichment of these differentially expressed genes and proteins. The Kyoto encyclopedia of genes and genomes results showed that these differentially expressed genes and proteins are enriched in the fatty acid degradation and histidine metabolism signaling pathways. We performed parallel reaction monitoring (PRM) verification of the differentially expressed proteins, and the PRM results were consistent with the sequencing results.ConclusionOur study provided and identified the differentially expressed genes and proteins. In addition, identifying functional genes and proteins with important breeding value will provide genetic resources and technical support for the breeding and industrialization of new genetically modified beef cattle breeds.

The Meat of the Matter: Environmental Dissemination of Beef Cattle Agrochemicals.

Global demand for beef is projected to increase into the foreseeable future (Smith et al., 2018). This article is protected by copyright. All rights reserved.

Amino Acid Nutrition and Reproductive Performance in Ruminants.

Amino acids (AAs) are essential for the survival, growth and development of ruminant conceptuses. Most of the dietary AAs (including L-arginine, L-lysine, L-methionine and L-glutamine) are extensively catabolized by the ruminal microbes of ruminants to synthesize AAs and microbial proteins (the major source of AAs utilized by cells in ruminant species) in the presence of sufficient carbohydrates (mainly cellulose and hemicellulose), nitrogen, and sulfur. Results of recent studies indicate that the ruminal microbes of adult steers and sheep do not degrade extracellular L-citrulline and have a limited ability to metabolize extracellular L-glutamate due to little or no uptake by the cells. Although traditional research in ruminant protein nutrition has focused on AAs (e.g., lysine and methionine for lactating cows) that are not synthesized by eukaryotic cells, there is growing interest in the nutritional and physiological roles of AAs (e.g., L-arginine, L-citrulline, L-glutamine and L-glutamate) in gestating ruminants (e.g., cattle, sheep and goats) and lactating dairy cows. Results of recent studies show that intravenous administration of L-arginine to underfed, overweight or prolific ewes enhances fetal growth, thedevelopment of brown fat in fetuses, and thesurvival of neonatal lambs. Likewise, dietary supplementation with either rumen-protected L-arginine or unprotected L-citrulline to gestating sheep or beef cattle improved embryonic survival. Because dietary L-citrulline and L-glutamate are not degraded by ruminal microbes, addition of these two amino acids may be a new useful, cost-effective method for improving the reproductive efficiency of ruminants.

Growth of beef cattle as prediction for meat production: A review

Growth of beef cattle as prediction for meat production: A review

Metabolic studies reveal that ruminal microbes of adult steers do not degrade rumen-protected or unprotected L-citrulline.

In vitro and in vivo experiments were conducted to determine the metabolism of rumen-protected or unprotected l-citrulline (Cit) plus l-glutamine (Gln) by ruminal microbes. In the in vitro experiment, whole ruminal fluid (3 mL, containing microorganisms) from steers was incubated at 37 ºC with 5 mM Cit plus 6 mM Gln (in a rumen-protected or unprotected form) for 0, 0.5, 2, or 4 h after which times 50 µL samples were collected for AA and ammonia analyses. In the in vivo experiment, at 0.5 h before and 0, 0.5, 1, 2, 4, and 6 h after cannulated adult steers consumed 0.56 kg dried-distillers' grain mixed with 70 g Cit plus 70 g Gln (in a rumen-protected or unprotected form), samples of ruminal fluid and jugular venous blood were obtained for AA analyses. Results from both in vitro and in vivo experiments demonstrated extensive hydrolysis of rumen-unprotected Gln into glutamate, but little degradation of the rumen-protected Gln or rumen-protected and unprotected Cit by ruminal microbes. Concentrations of Cit and arginine in the plasma of steers consuming rumen-protected or unprotected AA increased at 1 and 2 h after the meal, respectively, when compared with values at 0 h. Collectively, these novel findings indicate that ruminal microbes of adult steers do not degrade extracellular Cit in a rumen-protected or unprotected form. Our results refute the view that all dietary AAs are extensively catabolized by ruminal microorganisms and also have important implications for dietary supplementation with Cit to ruminants to enhance the concentration of arginine in their plasma and their productivity.

Ruminal microbes of adult steers do not degrade extracellular L-citrulline and have a limited ability to metabolize extracellular L-glutamate1,2

The microbial population within the rumen has long been considered to have the capability of extensively degrading all dietary AA. Results from our feeding trials revealed that this dogma is not correct. In vitro studies were conducted to test the hypothesis that certain AA undergo little degradation by ruminal microbes. Whole ruminal fluid (3 mL, containing microorganisms) from cannulated adult steers (~500 kg, n = 6) was incubated at 37 °C with 5 mM l-glutamine, l-glutamate, l-arginine, or l-citrulline for 0, 0.5, 1, and 2 h to determine time-dependent changes in the metabolism of these AA. Additional ruminal fluid was incubated with 0, 0.5, 2 or 5 mM l-glutamine, l-glutamate, l-arginine, or l-citrulline for 2 h to determine dose-dependent changes in their metabolism. An aliquot (50 µL) of the incubation solution was collected at the predetermined time points for AA analyses. There was extensive hydrolysis of l-glutamine into l-glutamate and ammonia, and l-arginine into l-ornithine, l-proline, and ammonia, but the near absence of catabolism of extracellular l-glutamate and no degradation of extracellular l-citrulline by ruminal microbes. There was little uptake of 14C-labeled l-glutamate and no detectable uptake of 14C-labeled l-citrulline by the cells. These results indicate, for the first time, that ruminal microbes of adult steers do not degrade extracellular l-citrulline and that metabolism of extracellular l-glutamate is negligible compared with their ability to extensively catabolize extracellular l-arginine and l-glutamine.

Link N as a Therapeutic Agent to Treat Pain Associated with Intervertebral Disc Degeneration

Introduction The intervertebral discs (IVDs) are the largest avascular tissues in the body characterized by an abundant extracellular matrix and low cell density, with innervation limited at the most peripheral annular layers. During IVD degeneration, the neurotrophins, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), can stimulate nerve growth and hyperinnervation of the inner annulus fibrosus (AF) and nucleus pulposus (NP), which further could lead to back pain. Back pain can potentially be suppressed by BMP4 supplementation to decrease the density of innervation. Link N is a naturally occurring peptide that can stimulate BMP4 in human IVDs. The aim of the present study was to determine the effect of Link N on NGF, BDNF, and substance P (SP) in human AF cells stimulated with cytokines or punctured bovine discs and determine the possible mechanisms related to its effect. Material and Methods Human lumbar spines were obtained through Héma-Québec harvesting organ donation within 24 hour after death. Annulus fibrosus (AF) cells were isolated from AF region of human IVDs with Thompson grade 2 of degeneration, cultured in monolayers and stimulated with TNFα (100 ng/mL) and IL1β (10 ng/mL) in the presence or absence of Link N (1 µg/mL) for 48 hours. Total RNA was isolated and gene expression of neurotrophins, substance P, and their receptors was measured using RT PCR. AF cells isolated from human IVDs with Thompson grade 4 were cultured for 48 hours with or without Link N (1 µg/mL) and the NGF release in the media was measured by Western blotting. Coccygeal IVDs from the tails of adult bovine steers (20–25 months) were isolated with the cartilaginous endplates. After 24 hours preconditioning in complete DMEM, the IVDs were treated (control, capsaicin [1.5 µg/mL), punctured by 16 G needle, punctured by 16 G needle and incubated with Link N [10 µg/mL]) and the disc culture media was collected at different time points for analysis. SP in the media was concentrated by solid phase extraction and was assayed by Elisa. Results Proinflammatory cytokines IL1β and TNFα have been shown to trigger the expression of NGF and SP, as well as promoting the degradation of the extracellular matrix in human IVD cells. Our results demonstrate that gene expression of NGF, BDNF, TrkA, and TrkB significantly decreased in human disc cells stimulated with either IL-1β or TNFα supplemented with Link N when compared with the control. Additionally, Link N was also able to inhibit NGF release in the media when AF grade 4 was stimulated with IL-1β. Link N supplementation also led to a significant decrease in SP after 24 hour in injured discs, when compared with controls. Conclusion Link N can suppress the stimulation of NGF, BDNF, and their receptors TrkA and TrkB, respectively, as well as the neurotransmitter SP in degenerate discs. This suggests that Link N has the potential to inhibit pain induced by neuronal innervation caused by disc degeneration. Thus, administration of Link N has the potential to not only repair the discs in early stages of the disease but also suppress pain.

Overdominance effect of the bovine ghrelin receptor (GHSR1a)-DelR242 locus on growth in Japanese Shorthorn weaner bulls: heterozygote advantage in bull selection and molecular mechanisms.

Ghrelin and the ghrelin receptor (GHSR1a) are involved in growth hormone secretion, food intake, and several other important functions. Ghrelin acts on GHSR1a and induces signal transduction via the Gαq subunit. In our previous study, we identified the DelR242 (3R) allele, a truncated 3-arginine residue (3R) [major type: 4 arginine residues (4R)] of the third intracellular loop of GHSR1a, with a high frequency in Japanese Shorthorn bulls (0.43) but with a low frequency in other cattle breeds (0.00–0.09). To further investigate the reasons for the higher frequency of the 3R allele, we performed several experiments. In this study, we found a significant sex difference in the frequency of the 3R allele. Statistical analysis revealed a significant overdominance effect of the DelR242 locus on growth in Japanese Shorthorn weaner bulls. However, additive/dominance/overdominance effects of the 3R allele on carcass traits in adult steers and dams were not significant. The mode of the overdominance effect was estimated to be solely controlled by the single DelR242 locus without any other linked loci using linkage disequilibrium analysis in GHSR1a. These results indicated that 4R/3R heterozygotes had a selective advantage in weaner bulls because of their higher average daily gain than homozygotes. We discussed possible molecular mechanisms involved in the overdominance effect of the DelR242 locus on these traits in weaner bulls using a structural model of the complex consisting of a GHSR1a dimer and Gαq.

Characterization of transcriptional complexity during adipose tissue development in bovines of different ages and sexes.

BackgroundAdipose tissue has long been recognized to play an extremely important role in development. In bovines, it not only serves a fundamental function but also plays a key role in the quality of beef and, consequently, has drawn much public attention. Age and sex are two key factors that affect the development of adipose tissue, and there has not yet been a global study detailing the effects of these two factors on expressional differences of adipose tissues.ResultsIn this study, total RNA from the back fat of fetal bovines, adult bulls, adult heifers and adult steers were used to construct libraries for Illumina next-generation sequencing. We detected the expression levels of 12,233 genes, with over 3,000 differently expressed genes when comparing fetal and adult patterns and an average of 1000 differently expressed genes when comparing adult patterns. Multiple Gene Ontology terms and pathways were found to be significantly enriched for these differentially expressed genes. Of the 12,233 detected genes, a total of 4,753 genes (38.85%) underwent alternative splicing events, and over 50% were specifically expressed in each library. Over 4,000 novel transcript units were discovered for one library, whereas only approximately 30% were considered to have coding ability, which supplied a large amount of information for the lncRNA study. Additionally, we detected 56,564 (fetal bovine), 65,154 (adult bull), 78,061 (adult heifer) and 86,965 (adult steer) putative single nucleotide polymorphisms located in coding regions of the four pooled libraries.ConclusionHere, we present, for the first time, a complete dataset involving the spatial and temporal transcriptome of bovine adipose tissue using RNA-seq. These data will facilitate the understanding of the effects of age and sex on the development of adipose tissue and supply essential information towards further studies on the genomes of beef cattle and other related mammals.

NMR-Relaxation and PFG NMR Studies of Water Dynamics in Oriented Collagen Fibres with Different Degree of Cross-linking

For collagen based tissue engineering it is important to know how the changes in water-biomolecules interactions are handled by the degree of cross-links in collagen nano-scaffolds. When hydration properties of collagens with different cross-linking are detailed by NMR a role of water interactions in improving collagen scaffold characteristics for tissue engineering could be clarified. A description of water diffusion in collagen fibres with cross-links should lead to better understanding of internal interactions and knowledge of porous media structure of collagen tissues. This paper presents the results of one- and two-dimensional NMR methods in studying molecular anisotropy and microstructure of collagen fibres from 2 connective tissues with different cross-linking levels (fibres from adult steer and young calf) at water content of 0.6 g water/g of dry matter. The NMR relaxation times (T1 and T2) have been studied in oriented collagen fibres (at 0° to the static magnetic field B0). The apparent translation diffusion coefficients (Dapp) at two directions of applied gradient – along the direction of static magnetic field B0 and perpendicular to B0 – have been studied in oriented collagen fibres (at 0° to the static magnetic field B0). The diffusion time dependence of Dapp showed for both directions of applied gradient a restriction for motion of water molecules. A model of equally spaced plane parallel permeable barriers developed by Tanner for NMR diffusion studies has been used for the estimation of restricted distance and permeability coefficient. Anisotropy of Dapp in oriented fibres was observed in both collagen tissues. Application of 2D DDCOSY NMR spectroscopy with two pairs of collinear gradients on collagen fibres oriented along the static magnetic field and simulations of diffusion anisotropy showed similar features on 2D diffusion maps.

Effect of Link N on the Expression of Neurotrophins and Substance P Release by Human Intervertebral Disc Cells Stimulated with Proinflammatory Cytokines

IntroductionAlthough there are different causes of low back pain, intervertebral disc (IVD) degeneration is one of them. In healthy discs, nociceptive nerve fibers and mechanoreceptors penetrate up...

Cross‐link stabilization does not affect the response of collagen molecules, fibrils, or tendons to tensile overload

We investigated whether immature allysine-derived cross-links provide mechanically labile linkages by exploring the effects of immature cross-link stabilization at three levels of collagen hierarchy: damaged fibril morphology, whole tendon mechanics, and molecular stability. Tendons from the tails of young adult steers were either treated with sodium borohydride (NaBH₄) to stabilize labile cross-links, exposed only to the buffer used during stabilization treatment, or maintained as untreated controls. One-half of each tendon was then subjected to five cycles of subrupture overload. Morphologic changes to collagen fibrils resulting from overload were investigated using scanning electron microscopy, and changes in the hydrothermal stability of collagen molecules were assessed using hydrothermal isometric tension testing. NaBH4 cross-link stabilization did not affect the response of tendon collagen to tensile overload at any of the three levels of hierarchy studied. Cross-link stabilization did not prevent the characteristic overload-induced mode of fibril damage that we term discrete plasticity. Similarly, stabilization did not alter the mechanical response of whole tendons to overload, and did not prevent an overload-induced thermal destabilization of collagen molecules. Our results indicate that hydrothermally labile cross-links may not be as mechanically labile as was previously thought.

Babesia bovis biological clones and the inter-strain allelic diversity of the Bv80 gene support subpopulation selection as a mechanism involved in the attenuation of two virulent isolates

The virulence phenotype of Babesia bovis subpopulations was evaluated using biological clones derived from the high-virulence BboS2P and the low-virulence BboR1A strain and two original virulent isolates, BboL15 and BboL17, multiplied extensively in vitro or attenuated by successive passages in splenectomized calves. The virulence phenotype was assessed both by inoculation of normal Holstein adult steers and by analyses of polymorphic fragments of the single-copy Bv80 gene as a subpopulation marker. BboS2P and its nine derived clones contained a single 750bp fragment with identical nucleotide sequences and numbers of repeats. A single fragment of approximately 850bp was observed in BboR1A and its derived clones (Ca3B1, Ca2B1). Ca3B1 and Ca2B1 were differentiated by a stable deletion of 15 contiguous nucleotides in the Bv80 allele of Ca3B1. Both alleles were identified in the parental strain. Original isolates BboL15 and BboL17 contained two Bv80 fragments of different sizes. Interestingly, the heavy and light fragments persisted in the in vivo-attenuated strains and the virulent in vitro-multiplied strains, respectively. Despite the inter-strain allelic diversity of the Bv80 gene, the fragments had identical nucleotide sequences and numbers of repeats compared to their respective parental Bv80 genes. The high-virulence and low-virulence phenotypes remained unchanged after they were multiplied in vitro. In conclusion, the polymorphic B. bovis Bv80 gene, was a useful marker for differentiating subpopulations with different phenotypes. The brevity of the procedure to isolate one parasite from the original isolate or strain before in vitro cloning and the fact that the continuous in vitro multiplication did not modify the virulence phenotype of B. bovis clones strongly suggest that the in vivo-attenuated subpopulations existed in the original isolates before they were selected by passages in splenectomized calves.

Lesion Development and Replication Kinetics During Early Infection in Cattle Inoculated With Vesicular Stomatitis New Jersey Virus Via Scarification and Black Fly (Simulium vittatum) Bite

Vesicular stomatitis viruses are the causative agents of vesicular stomatitis, an economically important contagious disease of livestock that occurs in North, Central, and South America. Little is known regarding the early stages of infection in natural hosts. Twelve adult Holstein steers were inoculated with Vesicular stomatitis New Jersey virus (VSNJV) on the coronary bands (CB) of the feet via scarification (SC) or by VSNJV-infected black fly (Simulium vittatum) bite (FB). Three additional animals were inoculated on the neck skin using FB. Clinical disease and lesion development were assessed daily, and animals were euthanatized from 12 hours post inoculation (HPI) through 120 HPI. The animals inoculated in the neck failed to develop any clinical signs or gross lesions, and VSNJV was detected neither by in situ hybridization (ISH) nor by immunohistochemistry (IHC). Lesions on the CB were more severe in the animals infected by FB than by SC. In both groups, peak VSNJV replication occurred between 24 and 48 HPI in keratinocytes of the CB, as evidenced by ISH and IHC. There was evidence of viral replication limited to the first 24 HPI in the local draining lymph nodes, as seen through ISH. Successful infection via FB required logarithmically less virus than with the SC technique, suggesting that components in black fly saliva may facilitate VSNJV transmission and infection in cattle. The lack of lesion development in the neck with the same method of inoculation used in the CB suggests that specific characteristics of the CB epithelium may facilitate VSNJV infection.

Biosensor-based detection of reduced sex hormone-binding globulin binding capacities in response to growth-promoter administrations

Growth-promoting agents are illicitly used during animal rearing processes and the detection of their use is limited by new compounds and dosing practices that limit the efficiency of current testing which is based on residue analysis by liquid chromatography–tandem mass spectrometry (LC–MS/MS) and gas chromatography–mass spectrometry (GC–MS) methodology. An alternative approach is to use indirect biological evidence as a screening tool to identify growth-promoter treated animals thus improving the effectiveness of residue testing through the targeted sampling of these animals. Sex hormone-binding globulin (SHBG) is a glycoprotein which binds and controls the levels of sex-hormones within the circulation. Using a biosensor assay based on measurement of binding to an immobilised 1α-dihydrotestosterone (1α-DHT) derivative, reduced SHBG binding capacities were detected in growth-promoter treated animals. During the course of a veal treatment regime based on repeated oestradiol benzoate, nortestosterone decanoate and dexamethasone administrations, treated male and female calves were shown to have significantly lower SHBG capacities. To assess the effectiveness of using SHBG binding capacities as a biomarker of treatment and to investigate the role of individual growth-promoter components to the SHBG capacity lowering effects, adult heifer animals were subjected to repeated doses of nortestosterone decanoate. These animals also demonstrated a reduction in SHBG capacity levels at Day 39 of the study, in contrast to oestradiol benzoate treated adult steers who were found to have unaltered levels. These findings suggest that the measurement of SHBG binding capacities using a biosensor assay has potential in the identification of illegally treated animals, particularly those exposed to androgens.

Isolation and in vitro culture of intramuscular pre-adipocytes from Luxi adult Yellow cattle

AbstractThree Luxi adult Yellow steers were used to isolate and culture intramuscular pre-adipocytes in vitro as well as to examine factors influencing their proliferation and differentiation. The intramuscular pre-adipocytes were taken from adipose tissues within muscles between the sixth and seventh rib and cultured after digestion with collagenase I. The results showed that the separated cell populations were highly homogeneous, proliferative and doubled within 62 h. When the confluent pre-adipocytes were treated with 10 μg/ml insulin and 0.25 μmol/l dexamethasone, small lipid droplets appeared on day 2 and the number of lipid droplets rapidly increased around the nuclei on day 6. Their dynamic morphological changes, growth curve, Oil Red O staining, and reaction to insulin and dexamethasone all verified their pre-adipocyte identity. Under controlled conditions, the intramuscular pre-adipocytes resumed proliferating and differentiating in vitro. Interestingly, the proportion of cultured diploid pre-adipocytes reached more than 90% after six repeated cultures. This study confirms the existence of functionally active pre-adipocytes within the muscles of Chinese adult local breed cattle. These cell strains are a potentially useful model for understanding further the mechanism of intramuscular adipose deposition in tissues, in order to improve beef quality based on Chinese local breed beef cattle.

Ability of near infrared reflectance spectroscopy (NIRS) to estimate physical parameters of adult steers (oxen) and young cattle meat samples

The potential of NIRS-based models to predict several physical parameters of oxen and young cattle beef protected by a quality mark was evaluated. Fifty-three and 67 samples of Longissimus thoracis muscle corresponding to oxen and young cattle reared in extensive conditions were analyzed for pH, colour ( L ∗, a ∗, b ∗), water holding capacity (WHC) and Warner–Braztler shear force (WBSF), according to the conventional methods. Several factors which might have jeopardized the prediction of pH, a ∗, WHC and WBSF by NIRS are considered in the discussion section. However, the best NIR calibrations, tested by full cross-validation, were for L ∗ ( R 2 = 0.869; SE CV = 1.56) and b ∗ ( R 2 = 0.901; SE CV = 1.08) colour parameters in meat samples from young cattle. It can be concluded that NIRS could be a useful tool for estimating the colour of young cattle meat samples, primary consideration for consumers when making purchasing decisions.

Discrimination of adult steers (oxen) and young cattle ground meat samples by near infrared reflectance spectroscopy (NIRS)

Near infrared reflectance spectroscopy (NIRS) was used to discriminate different types of ground beef samples. Fifty-three and sixty-seven samples of longissimus thoracis muscle corresponding to adult castrated steers (over 4 years old) and young cattle (under 14 months old), respectively, were homogenized and scanned over the NIR range (1100–2500 nm). The results showed that NIRS could successfully discriminate 100% of ground beef samples depending on the sort of animal, probably as a consequence of differences in the intramuscular fat and water contents. Thus, NIRS is a fast, inexpensive, and non-destructive method that can be used to discriminate these beef products.