Metabolomic analysis of longissimus from underperforming piglets relative to piglets with normal preweaning growth

Background: Recent increases in intra-litter variability in weaning weight have raised swine production costs. A contributor to this variability is the normal birth weight pig that grows at a slower rate than littermates of similar birth weight. The goal of this study was to interrogate biochemical profiles manifested in skeletal muscle originating from slow growing(SG) and faster growing littermates(control), with the aim of identifying differences in metabolic pathway utilization between skeletal muscle of the SG pig relative to its littermates. Samples of longissimus muscle from littermate pairs of pigs were collected at 21 d of age for metabolomic analysis.Results: Birth weights did not differ between littermate pairs of SG and Control pigs(P > 0.05). Weaning weights differed by 1.51 ± 0.19 kg(P < 0.001). Random forest(RF) analysis was effective at segregating the metabolome of muscle samples by growth rate, resulting in a predictive accuracy of 81% versus random segregation(50%).Decreases in sugars in the pentose phosphate pathway(PPP) in the longissimus of SG pigs were detected(P < 0.05). Decreases were also apparent in glycolytic intermediates(glycerol-3-phosphate and lactate) and key glycolysis-derived intermediates(glucose-6-phosphate and fructose-6-phosphate; P < 0.05). SG pigs had increased levels of phospholipids, lysolipids, diacylglycerols, and sphingolipids(P < 0.05). Pathway analysis identified a cluster of molecules associated with muscle and collagen/extracellular matrix breakdown that are increased in the SG pig(glutamate, 3-methylhistidine and hydroxylated proline moieties; P < 0.05). Nicotinate metabolism was altered in SG pigs, resulting in a 78% decrease in the nicotinamide adenine dinucleotide pool(P < 0.05).Conclusions: These metabolomic data provide the first evidence for biochemical mechanisms that should be investigated to determine if they have a potential role in the slow growth in some normal birth weight piglets that contribute to increased intra-litter variability in weaning weights and provides essential information and potential targets for the development of nutritional intervention strategies.

Dietary supplementation of Lonicera macranthoides leaf powder improves amino acid profiles in serum and longissimus thoracis muscle of growing-finishing pigs

A 60-days feeding trial was conducted to determine the effect of dietary supplementation of Lonicera macranthoides leaf(LML) on growth performance, meat quality, and free amino acid profiles in growingfinishing pigs. L. macranthoides leaves were harvested, air-dried and milled to powder. A total of 288 crossbred barrows(Large White x Landrace) with an average initial BW of 54.0 ± 3.4 kg were randomly allocated to 3 treatment groups and fed either a basal diet or a diet supplemented with 0.5% or 1.0% LML powder. Results showed that diet supplemented with LML powder did not affect average daily feed intake(ADFI) and feed: gain ratio(P> 0.05) in growing-finishing pigs. Moreover, diet supplemented with LML powder showed no significant effects on carcass traits(P > 0.05) including dressing percentage,backfat thickness and loin muscle area, and meat quality traits(P > 0.05) including meat color, intramuscular fat and cooking loss. However, diet supplemented with LML powder significantly improved free amino acid profiles in serum and longissimus thoracis muscle in growing-finishing pigs. Most importantly, dietary LML powder increased total free amino acids content(P < 0.001) and essential free amino acid content(P < 0.001) in longissimus thoracis muscle. These results indicate that LML has the potential to improve the nutritional value of meat through improving free amino acid profiles.

iTRAQ-based quantitative proteomic analysis of longissimus muscle from growing pigs with dietary supplementation of non-starch polysaccharide enzymes

Non-starch polysaccharide enzymes（NSPEs） have long been used in the feed production of monogastric animals to degrade non-starch polysaccharide to oligosaccharides and promote growth performance. However, few studies have been conducted on the effect of such enzymes on skeletal muscle in monogastric animals. To elucidate the mechanism of the effect of NSPEs on skeletal muscle, an isobaric tag for relative and absolute quantification（i TRAQ） for differential proteomic quantitation was applied to investigate alterations in the proteome in the longissimus muscle（LM） of growing pigs after a 50-d period of supplementation with 0.6% NSPEs in the diet. A total of 51 proteins were found to be differentially expressed in the LM between a control group and the NSPE group. Functional analysis of the differentially expressed protein species showed an increased abundance of proteins related to energy production, protein synthesis, muscular differentiation, immunity, oxidation resistance and detoxification, and a decreased abundance of proteins related to inflammation in the LM of the pigs fed NSPEs. These findings have important implications for understanding the mechanisms whereby dietary supplementation with NSPEs enzymes can promote growth performance and improve muscular metabolism in growing pigs.

Meridian-like character of reflex electromyogram activity in longissimus dorsi muscles

We studied the temporal and spacial character of the electromyogram (EMG) evoked by acupuncture in long-issimus dorsi (LD) muscles of rat, and evaluated the effect of needling direction or local blockade on EMG propagation. When certain sites on LD muscle were acupunctured, asynchronous EMG could be activated not only at the acupunctured point, but also within the muscle region supplied by the adjacent 2-3 vertebral segments. The EMG evoked by stimulation on the borderline of aponeurosis and muscle venter was larger in amplitude than those on the other sites in the same vertebral segment. When the distance from the recorded site to stimulated site increased, the EMG amplitude decreased, and its latency prolonged. Acupuncture in an oblique direction toward rostral or caudal side of the muscle enhanced the EMG amplitude in the same direction. EMG activity was weakened and its propagation was blocked by local injection of procaine. These results indicated that the character of EMG propagation evoked by

Evaluation of Physicochemical,Microbiological and Sensory Stability of Frozen Stored Vacuum-Packed Lamb Meat

Nowadays, lamb meat represents only 7% of all meat produced in the world. In recent years the demand for standardized lamb meat cuts has been considered of great importance and the marketing occurs predominantly in the form of frozen cuts. Herewith, the main of this work was to evaluate the stability and safety of lamb meat during frozen storage. Meats were vacuum packed in high barrier multilayer plastic iflms and stored during 12 mon at （-18±1）℃. The meat stability was assessed by physical and chemical （lipid oxidation, objective color, pH value, cooking losses and instrumental texture）, microbiological （total count of psychrotrophic, coliform count at 45℃, coagulase-positive staphylococci and the presence of Salmonella） and sensory analysis （acceptance test and visual evaluation）. The vacuum packed lamb meat remained stable as to most physical and chemical indexes. Microbiological indexes showed good stability throughout the storage period according to Brazilian legislation standards to pathogenic microorganisms. Although a signiifcant reduction in tenderness （shear force increase from 3 to 8 kg）, it showed a good sensorial acceptance for all attributes tested, including texture, with scores of around 7 （like moderately） during the 12 mon of storage. Therefore, it can be concluded that, under the conditions applied in this study, lamb meat presents a shelf life of at least 12 mon when stored at-18℃.

Effects of organic chromium supplementation to finishing lambs diet on growth performance, carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium（Cr） to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs（age（4.5±0.2） mon;（25.8±3.6） kg body weight（BW）） were randomly assigned to three levels of supplemental organic Cr（0.0, 0.2 and 0.4 mg kg^–1 dry matter（DM）） in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed（contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels（0.2＋0.4） ppm Cr）. Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased（P〈0.05） as organic Cr level increased in the diet. Kidney fat decreased linearly（P〈0.05） as supplemental Cr increased. In Longissimus dorsi（LD）, the ash content decreased linearly, and shear force（kg cm^–2） increased（P〈0.05） as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.

Cloning and Identification of Porcine HSPC117 Gene Differentially Expressed in F_(1)Crossbreds and Their Parents

To investigate the molecular basis of porcine heterosis, suppression subtractive hybridization （SSH） was performed to detect the differences in gene expression between porcine longissimus dorsi of Meishan X Large White （MS × LW） F1 hybrids and their parents Meishan pigs. An expression sequence tag （EST） differentially expressed was found, designated as ML556, which was homologous to a hypothetical protein HSPC117, from human hematopoietic stem/progenitor cells （HSPCs）, and the full-length cDNA of porcine HSPC117 was cloned using rapid amplification of cDNA ends （RACE） method. Translation of the mRNA transcript revealed an open reading frame （ORF） of 505 amino acid residues encoding a peroxisomal targeting signal （PTS） with theoretical molecular weight of 55 kDa. Alignment analysis revealed that the deduced protein sequence exhibit 98, 98, 98, 97, and 97% identity with that of cattle, human, dog, rat, and mouse, respectively. The tissue expression analysis indicated that the porcine HSPC117 gene is highly expressed in muscle, spleen, lung, kidney, uterus, ovary and testis, moderately expressed in fat, heart, and liver, and not expressed in stomach and small intestine. The possible role of porcine HSPC117 and its relationship with porcine heterosis were discussed.

Organic practices and gender are effective strategies to provide healthy pork loin

This study evaluated the influence of husbandry（organic feed and management but not free-ranging vs. conventional） and sex（barrows vs. gilts） on pork meat quality. A total of 60 Longissimus thoracis pork muscle samples from different 3-way crossbred genotypes were chosen from 3 conventional and 2 organic pig farms. Technological meat quality was measured at 24 h post-mortem and muscle fatty acid content and composition was analysed by gas chromatography. The loin from organic pigs at 24 h of retail display had lower pH, but it had no detrimental effects on drip loss. All the International Commission on Illumination colour attributes except meat lightness differed between husbandry systems. Moisture and crude protein content were lower whereas intramuscular fat content was greater in organic than in conventional pork. Total saturated fatty acid（SFA）, monounsaturated fatty acid（MUFA）, polyunsaturated fatty acid（PUFA） and PUFA n-6 contents did not differ between husbandry systems, but total PUFA n-3（mainly C18：3 n-3） were greater in organic than in conventional pork. Sex did not affect ultimate p H or meat colour attributes but barrows showed lower moisture and greater intramuscular fat than gilts. Total SFA and MUFA content were similar but all the PUFA（both n-6 and n-3） were lower in barrows than in gilts. These results suggest that some bioactive compounds from dietary origin, i.e., linolenic acid（C18：3 n-3） content from dietary vegetable oils（soybean or olive olein）, might be used to highlight the nutritive value of（not free-ranging） organic pork meat. In addition, gilts were leaner than barrows and showed a more favourable PUFA/SFA ratio.