Quality traits of suckling-lamb meat covered by the protected geographical indication “Lechazo de Castilla y León” European quality label

The quality of suckling-lamb meat (derived from Churra, Castellana and Ojalada breeds), covered by the protected geographical indication (PGI) “Lechazo de Castilla y León”, and the effects of carcass weight (CW), breed and sex on quality were studied. The edible portion (EP) of 81 carcasses was analysed for proximate composition, fatty acid, cholesterol, amino acid and mineral contents. The longissimus thoracis and lumborum muscle (30 samples) were analysed for proximate composition, pH, myoglobin content, water holding capacity, Warner–Bratzler shear force, and total and soluble collagen content. This study contributes to characterization of suckling-lamb meat quality recognised in the European Union with a PGI label and provides new data on the composition of the EP of the carcasses. CW and breed had a significant effect on several quality traits, most related to fatness.     

Estrogen - Induced release of luteinizing hormone in prepubertal and postpubertal heifers

This experiment was designed to determine the age at which estradiol-17beta (E(2)) first induces a preovulatory-like surge of luteinizing hormone (LH) in prepubertal heifers. Responses of prepubertal animals 3 to 4 and 5 to 6 months of age were compared with those of postpubertal heifers that received 25 mg prostaglandin F(2)alpha at 0800 hr on day 15 of the estrous cycle. E(2) (500mug) induced surges of LH in 1 5 heifers 3 to 4 months of age, 3 3 heifers 5 to 6 months of age and 5 5 postpubertal heifers. Duration of response and interval between E(2) injection and peak of the response were longer in postpubertal heifers than in those 5 to 6 months old (P<0.10). Peak response and total amount of LH released were greater in animals 5 to 6 months old (P<0.10). Only one prepubertal heifer had elevated concentrations of progesterone following an LH surge. Four of 5 postpubertal heifers receiving E(2) and 3 of 4 postpubertal heifers receiving corn oil had corpora lutea and similar patterns of progesterone concentrations. We conclude that ability to release an LH surge in response to E(2) develops in heifers between 3 and 5 months of age, but that this induced surge does not cause ovulation.     

Dispersed central place foraging in Australian meat ants

Summary Australian meat ants often inhabit colonies with widely dispersed nest holes, and this study examines how resource is harvested and distributed in a colony ofIridomyrmex sanguineus Smith (Formicidae: Dolichoderinae). The three principal types of foragers (tenders, honeydew transporters, scavengers) exhibited nest hole fidelity, where harvested resource was consistently delivered to the same nest hole by each foraging individual. Australian meat ants thus use a harvesting system based on dispersed central place foraging. Evidence of frequent larval transport among nest holes, age polyethism developing in the direction of foraging, and the tendency for nest-associated workers to accept new nest holes more readily than foragers, suggests that workers develop fidelity to the particular nest hole in which they eclose. Coupled with larval transport, nest hole fidelity may allow a colony with widely dispersed nest holes to adjust its structure to more efficiently harvest a resource distributed unevenly in space or time.     

Influences of month of birth and age on patterns of luteinizing hormone secretion in prepubertal heifers

An experiment was done to determine if month of birth and age influenced patterns of luteinizing hormone (LH) secretion in prepubertal heifers. Mean concentrations of LH increased linearly (P < .05) in March-born heifers between one and seven months of age. This was partially due to an increase in number of LH pulses. The prepubertal pattern of LH concentrations was quadratic (P < .05) for heifers born in September because concentrations were slightly higher (P = .15) than those in March-born heifers at one month of age. There were no differences between groups during the remainder of the prepubertal period (3 to 7 months). There was a tendency (P = .18) for September-born animals to reach puberty at younger ages than those born in March. September-born heifers also had greater (P = .06) average daily gains, but body weights at puberty were similar for the two groups. These results show that season of birth influenced LH concentrations at one month of age, but did not significantly affect the increase between three and seven months of age.     

Proteome changes underpin improved meat quality and yield of chickens (Gallus gallus) fed the probiotic Enterococcus faecium

Background

Supplementation of broiler chicken diets with probiotics may improve carcass characteristics and meat quality. However, the underlying molecular mechanism remains unclear. In the present study, 2D-DIGE-based proteomics was employed to investigate the proteome changes associated with improved carcass traits and meat quality of Arbor Acres broilers (Gallus gallus) fed the probiotic Enterococcus faecium.

Results

The probiotic significantly increased meat colour, water holding capacity and pH of pectoral muscle but decreased abdominal fat content. These meat quality changes were related to the altered abundance of 22 proteins in the pectoral muscle following E. faecium feeding. Of these, 17 proteins have central roles in regulating meat quality due to their biological interaction network. Altered cytoskeletal and chaperon protein expression also contribute to improved water holding capacity and colour of meat, which suggests that upregulation of chaperon proteins maintains cell integrity and prevents moisture loss by enhancing folding and recovery of the membrane and cytoskeletal proteins. The down-regulation of β-enolase and pyruvate kinase muscle isozymes suggests roles in increasing the pH of meat by decreasing the production of lactic acid. The validity of the proteomics results was further confirmed by qPCR.

Conclusions

This study reveals that improved meat quality of broilers fed probiotics is triggered by proteome alterations (especially the glycolytic proteins), and provides a new insight into the mechanism by which probiotics improve poultry production.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1167) contains supplementary material, which is available to authorized users.     

基于RNA-Seq转录组测序技术揭示肉兔生长发育调控的分子机制

为研究肉兔肌肉生长发育调控的分子机制,本试验以84日龄齐卡巨型白兔和齐兴肉兔为研究对象,屠宰后取背最长肌组织并提取总RNA,反转录建立c DNA文库,利用Illumina HiSeq 2500测序平台进行测序,并进行序列分析和注释。筛选与肉兔肌肉生长发育相关的信号通路及差异表达基因,最后进行荧光定量PCR验证。结果表明:齐卡巨型白兔和齐兴肉兔背最长肌中显著差异表达基因总数为833个,其中齐卡巨型白兔中显著上调基因325个,显著下调基因508个。KEGG功能注释发现差异基因显著富集到PI3K-AKT通路、癌症通路和黏着斑通路,最终筛选出4个可能与生长发育显著相关的差异表达基因,为进一步对肉兔进行遗传改良提供了理论基础。     

2D DIGE proteomic analysis of early post mortem muscle exudate highlights the importance of the stress response for improved water‐holding capacity of fresh pork meat

Variation in water‐holding capacity (WHC), which presents a major economic burden to the swine industry, is considered to be underpinned by variation at a molecular and biochemical level. High‐resolution 2D DIGE followed by MS analysis and Western blot were used to unravel the proteome of muscle exudate, collected following centrifugation, in the pH 4–7 range. A first 2DE‐based protein map of this substrate was produced where 89 spots were successfully characterised. Two phenotypes divergent for WHC plus one intermediate were compared with a view to deciphering the biochemical processes impacting on variation in WHC. Twenty spots were observed to be altered across the phenotypes. Of these, 14 represented sixteen proteins including metabolic enzymes, stress response proteins and structural proteins. Triosephosphate isomerase and transferrin showed a major difference between the two extreme phenotypes, and may have potential as biological markers for WHC prediction. Several members of the HSPs family were highlighted. This proteomic study makes an important contribution towards a more detailed molecular view of the processes behind WHC and will provide a valuable resource for future investigations.     

Preface

The aim of the study was to introduce a convenient method for identification of differences among individual animals in genes supposed to influence meat performance in pigs. The set of seven candidate genes (IGF2, FOS, MC4R, DGAT1, MYF4, MYF, and MC3R) was used. To determine the genotypes, multiplex polymerase chain reaction (PCR) and minisequencing using SNaPshot system (Applied Biosystems; Forster City, CA, USA) were applied. The efficiency of this gene panel for routine testing in pigs was verified in the Black Pied P?e?tice pig breed by the statistical general linear model. The results showed that both the method and the gene panel are convenient for meat quality testing and offer reproducible results.     

Chianina beef tenderness investigated through integrated Omics

In the present study we performed an integrated proteomics, interactomics and metabolomics analysis of Longissimus dorsi tender and tough meat samples from Chianina beef cattle. Results were statistically handled as to obtain Pearson's correlation coefficients of the results from Omics investigation in relation to canonical tenderness-related parameters, including Warner Bratzler shear force, myofibrillar degradation (at 48 h and 10 days after slaughter), sarcomere length and total collagen content. As a result, we could observe that the tender meat group was characterized by higher levels of glycolytic enzymes, which were over-phosphorylated and produced accumulation of glycolytic intermediates. Oxidative stress promoted meat tenderness and elicited heat shock protein responses, which in turn triggered apoptosis-like cascades along with PARP fragmentation. Phosphorylation was found to be a key process in post mortem muscle conversion to meat, as it was shown not only to modulate glycolytic enzyme activities, but also mediate the stability of structural proteins at the Z-disk. On the other hand, phosphorylation of HSPs has been supposed to alter their functions through changing their affinity for target interactors. Analogies and breed-specific differences are highlighted throughout the text via a direct comparison of the present results against the ones obtained in a parallel study on Maremmana Longissimus dorsi. It emerges that, while the main cornerstones and the final outcome are maintained, post mortem metabolism in tender and tough meat yielding individuals is subtly modulated via specific higher levels of enzymes and amino acidic residue phosphorylation in a breed-specific fashion, and whether calcium homeostasis dysregulation was a key factor in Maremmana, higher early post mortem phosphocreatine levels in the Chianina tender group could favor a slower and prolonged glycolytic rate, prolonging the extent of the minimum hanging period necessary to obtain tender meat from this breed by a few days.     

Control of the risk of human toxoplasmosis transmitted by meat

One-third of the human world population is infected with the protozoan parasite Toxoplasma gondii. Recent calculations of the disease burden of toxoplasmosis rank this foodborne disease at the same level as salmonellosis or campylobacteriosis. The high disease burden in combination with disappointing results of the currently available treatment options have led to a plea for more effective prevention. In this review we describe Toxoplasma as a hazard associated with the consumption of undercooked meat or meat products and provide an analysis of the various options to control the risk of human toxoplasmosis via this source. Monitoring and surveillance programs may be implemented for pre-harvest control of Toxoplasma infection of farm animals, with the reduction of environmental oocyst load as the most important milestone. Alternatively, Toxoplasma safe meat can be obtained through simple post-harvest decontamination procedures, whereby freezing the meat may currently be the best option, although new technologies using irradiation or high-pressure treatment may offer promising alternatives. Influence of culture, religion and food handling customs may predispose a certain type of meat as an important source of infection, indicating that prevention needs to be tailored according to social habits in different regions in the world. The rationale for more stringent control measures to prevent toxoplasmosis both from disease and economic points of view is emphasized.