Meat quality, free fatty acid concentration, and oxidative stability of pork from animals fed diets containing different sources of selenium.

This study evaluates the effect of the source of dietary selenium supplementation (organic versus mineral) and the combined effect of organic selenium and vitamin E on the fatty acid composition and lipolysis in pork intramuscular fat and other meat quality characteristics such as drip loss and lipid stability. Higher vitamin E deposition, lower drip loss, and higher stability against oxidation were detected in muscle from pigs fed organic selenium. Also higher proportion of free fatty acids was observed in intramuscular fat from pigs fed organic selenium than those fed inorganic selenium, being these mainly coming from neutral lipid fraction. In addition, the inclusion of vitamin E in the diet enhanced such effect. Dietary organic selenium also increased Δ9-desaturase and elongase indexes and C18:1n-9 concentration. A related decrease of C18:0 concentration was also observed. Described differences in the lipid fraction composition could affect sensory characteristics of meat and meat products.

Developmental Stage, Muscle and Genetic Type Modify Muscle Transcriptome in Pigs: Effects on Gene Expression and Regulatory Factors Involved in Growth and Metabolism.

Iberian pig production includes purebred (IB) and Duroc-crossbred (IBxDU) pigs, which show important differences in growth, fattening and tissue composition. This experiment was conducted to investigate the effects of genetic type and muscle (Longissimus dorsi (LD) vs Biceps femoris (BF)) on gene expression and transcriptional regulation at two developmental stages. Nine IB and 10 IBxDU piglets were slaughtered at birth, and seven IB and 10 IBxDU at four months of age (growing period). Carcass traits and LD intramuscular fat (IMF) content were measured. Muscle transcriptome was analyzed on LD samples with RNA-Seq technology. Carcasses were smaller in IB than in IBxDU neonates (p < 0.001), while growing IB pigs showed greater IMF content (p < 0.05). Gene expression was affected (p < 0.01 and Fold change > 1.5) by the developmental stage (5,812 genes), muscle type (135 genes), and genetic type (261 genes at birth and 113 at growth). Newborns transcriptome reflected a highly proliferative developmental stage, while older pigs showed upregulation of catabolic and muscle functioning processes. Regarding the genetic type effect, IBxDU newborns showed enrichment of gene pathways involved in muscle growth, in agreement with the higher prenatal growth observed in these pigs. However, IB growing pigs showed enrichment of pathways involved in protein deposition and cellular growth, supporting the compensatory gain experienced by IB pigs during this period. Moreover, newborn and growing IB pigs showed more active glucose and lipid metabolism than IBxDU pigs. Moreover, LD muscle seems to have more active muscular and cell growth, while BF points towards lipid metabolism and fat deposition. Several regulators controlling transcriptome changes in both genotypes were identified across muscles and ages (SIM1, PVALB, MEFs, TCF7L2 or FOXO1), being strong candidate genes to drive expression and thus, phenotypic differences between IB and IBxDU pigs. Many of the identified regulators were known to be involved in muscle and adipose tissues development, but others not previously associated with pig muscle growth were also identified, as PVALB, KLF1 or IRF2. The present study discloses potential molecular mechanisms underlying phenotypic differences observed between IB and IBxDU pigs and highlights candidate genes implicated in these molecular mechanisms.

Early-postnatal changes in adiposity and lipids profile by transgenerational developmental programming in swine with obesity/leptin resistance.

Maternal malnutrition during pregnancy, both deficiency and excess, induces changes in the intrauterine environment and the metabolic status of the offspring, playing a key role in the growth, status of fitness/obesity and appearance of metabolic disorders during postnatal life. There is increasing evidence that these effects may not be only limited to the first generation of descendants, the offspring directly exposed to metabolic challenges, but to subsequent generations. This study evaluated, in a swine model of obesity/leptin resistance, the existence and extent of transgenerational developmental programming effects. Pre- and postnatal development, adiposity and metabolic features were assessed in the second generation of piglets, descendant of sows exposed to either undernutrition or overnutrition during pregnancy. The results indicated that these piglets exhibited early-postnatal increases in adiposity and disturbances in lipid profiles compatible with the early prodrome of metabolic syndrome, with liver tissue also displaying evidence of paediatric liver disease. These features indicative of early-life metabolic disorders were more evident in the males that were descended from overfed grandmothers and during the transition from milk to solid feeding. Thus, this study provides evidence supporting transgenerational developmental programming and supports the necessity for the development of strategies for avoiding the current epidemics of childhood overweight and obesity.

Quantification of γ- and α-tocopherol isomers in combination with pattern recognition model as a tool for differentiating dry-cured shoulders of Iberian pigs raised on different feeding systems.

BACKGROUND: Quantification of γ- and α-tocopherol in dry-cured shoulders of Iberian pigs was evaluated as a tool for differentiating feeding backgrounds or regimens. Samples (n = 115) were obtained over two different seasons from the four categories of pigs described in the Industry Quality Policy, i.e. pigs fed in free-range conditions (FREE-RANGE), pigs fed in free-range conditions and provided feed supplements (FREE-FEED), pigs fed outdoors with feed and with access to grass (FEED-OUT) and pigs fed in intensive conditions with feed (FEED). Linear discriminant functions were calculated and validated. RESULTS: The validation results showed that 20% of the muscle samples were not correctly classified into the four feeding categories, giving an 80% success rate. The FEED group had the lowest proportion of errors, with 100% of samples correctly classified. For the FREE-RANGE group, 87% of samples were assigned to the correct feeding system by cross-validation; however, 13% were considered as FREE-FEED. A higher rate of correct classification can be obtained when using three categories or by calculating the weight gain in free-range conditions using regression equations. CONCLUSION: Taking into account the high variability of the samples and the high success in classification, these results are of interest and may be applied in practical situations.

Lower Oral Doses of Micellized α-Tocopherol Compared to α-Tocopheryl Acetate in Feed Modify Fatty Acid Profiles and Improve Oxidative Status in Pigs.

This study evaluated the effect of vitamin E supplementation source, and the dose given to sows or piglets, on the fatty acid profile of colostrum, milk, subcutaneous and intramuscular fat, and the oxidative status of piglets at 39 days of age. Sows (n = 10) were given 150 mg dl-α-tocopheryl acetate/d in feed, or 75 or 50 mg micellized-d-α-tocopherol/d in water from Day 103 of pregnancy. Weaning piglets from each group of sows (n = 7) received 3.33 mg dl-α-tocopheryl acetate/d in feed, or 1.7 mg micellized-d-α-tocopherol/d or 1.1 mg micellized-d-α-tocopherol/d in water for 14 days. Colostrum from sows supplemented with micellized-d-α-tocopherol had a lower proportion of C20:0 (P = 0.02), C18:4 n-3 (P = 0.03) and a higher C18:1 n-9 to C18:0 ratio than those given dl-α-tocopheryl acetate. Supplementation with micellized-d-α-tocopherol decreased the C18:0 proportion (P = 0.04) and the C18:1 n-9 to C18:0 ratio (P = 0.03) in milk, whereas the C18:1 n-7 proportion increased (P = 0.03) compared to dl-α-tocopheryl acetate. Composition was affected by the d-α-tocopherol dose. A similar trend to that observed in milk was observed in fatty acid composition in piglet fat. Piglets supplemented with micellized-d-α-tocopherol at low doses did not have different ferric reducing antioxidant power in muscle tissues (P = 0.31) than when they were supplemented with dl-α-tocopheryl acetate. Piglets given 1.7 mg micellized-d-α-tocopherol/d had lower oxidized glutathione than those given 1.1 mg/d (P = 0.0055). In conclusion, oral supplementation of sows (75 mg/d) and piglets (1.7 mg/d) with micellized natural vitamin E modified the fatty acid profile of piglet tissues and improved their oxidative status.

Maternal malnutrition and offspring sex determine juvenile obesity and metabolic disorders in a swine model of leptin resistance.

The present study aimed to determine, in a swine model of leptin resistance, the effects of type and timing of maternal malnutrition on growth patterns, adiposity and metabolic features of the progeny when exposed to an obesogenic diet during their juvenile development and possible concomitant effects of the offspring sex. Thus, four groups were considered. A CONTROL group involved pigs born from sows fed with a diet fulfilling their daily maintenance requirements for pregnancy. The treated groups involved the progeny of females fed with the same diet but fulfilling either 160% or 50% of pregnancy requirements during the entire gestation (OVERFED and UNDERFED, respectively) or 100% of requirements until Day 35 of pregnancy and 50% of such amount from Day 36 onwards (LATE-UNDERFED). OVERFED and UNDERFED offspring were more prone to higher corpulence and fat deposition from early postnatal stages, during breast-feeding; adiposity increased significantly when exposed to obesogenic diets, especially in females. The effects of sex were even more remarkable in LATE-UNDERFED offspring, which had similar corpulence to CONTROL piglets; however, females showed a clear predisposition to obesity. Furthermore, the three groups of pigs with maternal malnutrition showed evidences of metabolic syndrome and, in the case of individuals born from OVERFED sows, even of insulin resistance and the prodrome of type-2 diabetes. These findings support the main role of early nutritional programming in the current rise of obesity and associated diseases in ethnics with leptin resistance.

Fetal and early-postnatal developmental patterns of obese-genotype piglets exposed to prenatal programming by maternal over- and undernutrition.

The present study evaluated the effect of nutritional imbalances during pregnancy, either by excess or deficiency, on fertility and conceptus development in obese-genotype swine (Iberian pig). Twenty-five multiparous sows were fed, from mating to farrowing, with a standard diet fulfilling either 1.6 folds their daily maintenance requirements for pregnancy (overfed group, n = 12) or only the 50% of such requirements (underfed group, n = 13). Ten out of 12 overfed but only two out of 13 underfed sows became pregnant (P<0.005). Fetal development was determined in the pregnant females at Days 35, 50, 75 and 90 of pregnancy. The embryos from undernourished sows were smaller than the embryos from overfed females as early as at 35 days of pregnancy (P<0.05) and remained smaller until Day 90 of gestation. However, at the end of pregnancy, there were significant changes in the developmental patterns of fetuses. Thus, weight and size of the offspring from both nutritional treatments were finally similar at delivery; the same was found at weaning. There was thereafter a sex-related effect on the growth during the early-postnatal period, with male piglets of both nutritional origins being significantly heavier and more corpulent at weaning that their sisters (P<0.05). In conclusion, fetal growth conditioned by malnutrition from periconceptional stages is mainly regulated at the end of the pregnancy, so that ensure an adequate body-weight and size and, therefore, the survival of the offspring. Afterwards, the early-postnatal development of the offspring is affected by sex, independently from nutritional origin, with male piglets growing faster than females.

Response of ApoA-IV in pigs to long-term increased dietary oil intake and to the degree of unsaturation of the fatty acids.

ApoA-IV is a protein constituent of HDL particles; the gene coding for it is a member of the ApoA-I-ApoC-III-ApoA-IV cluster. To investigate the effects of the quantity and the degree of saturation of dietary lipid on the long-term response of this Apo, and on the hypothetical coordinated regulation of the cluster in vivo, pigs were fed isoenergetic, cholesterol-free, low-lipid or lipid-enriched diets (containing either extra olive oil (rich in MUFA) or sunflower oil (rich in n-6 PUFA)) for 42 d. In animals fed on the control diet, ApoA-IV was mainly associated with plasma lipoproteins. An increase in plasma ApoA-IV concentration, mainly in the lipoprotein-free fraction, was induced by the lipid-enriched diets, independent of the degree of saturation of the fatty acids involved. The latter diets also led to increases in hepatic ApoA-I, ApoA-IV and ApoC-III mRNA levels, more so with the sunflower oil-rich diet. The present results show that porcine plasma ApoA-IV levels and their association with lipoproteins are very sensitive to increases in dietary lipids, independent of the degree of fatty acid saturation. Furthermore, hepatic expression of RNA appears to be coordinated along with that of the other members of the gene cluster.

Cloning, characterization and comparative analysis of pig plasma apolipoprotein A-IV.

Pig apolipoprotein (apo) A-IV cDNA was cloned, characterized and compared to the human ortholog. Mature porcine apo A-IV consists of 362 amino acids and displays a 75.6% sequence identity with human protein. Pig apo A-IV is the smallest reported mammalian apo A-IV because it lacks the repeated motifs of glutamine and glutamic acid at the carboxyl terminus. A phylogenic tree of apo A-IV mammalian proteins reveals that porcine apo A-IV is more closely related to humans and primates than to rodents. This protein is highly hydrophobic and is mainly associated with lipoproteins.

Effects of feeding elevated concentrations of monounsaturated fatty acids and vitamin E to swine on characteristics of dry cured hams.

Thirty Large White×Great York gilts were fed six experimental diets containing three levels of poly and monounsaturated fatty acids. Within each dietary fat treatment, one group was fed a basal level of vitamin E (20 mg α-tocopheryl acetate/kg diet) and the other group received a supplemented level (200 mg α-tocopheryl acetate/kg diet). Concentration of α-tocopherol was significantly higher in hams from pigs fed supplemented dietary levels of vitamin E (P<0.0001), but no significant effect of dietary fat was observed. Dietary vitamin E supplementation reduced the concentration of thiobarbituric acid reactive substances after 9 days storage of sliced samples (P<0.0001), while dietary fat source showed no significant effect. Significantly lower oxidation was observed in ham homogenates from pigs fed higher concentrations of monounsaturated fatty acids after 120 min of incubation under pro-oxidant conditions (P=0.013). No effect of dietary treatment was observed in ham volatile aldehyde profile. No significant effect of dietary vitamin E was observed on surface redness during storage, but a significant effect was observed for luminosity after 7 days of storage (P=0.033). Hams from pigs fed diets enriched in monounsaturated fatty acid showed higher 'a' values (P=0.040) in stored sliced samples. Sensory evaluation revealed a significant effect of dietary vitamin E on redness of ham slices (P<0.001). Dietary supplementation with vitamin E also produced a significantly higher odour and flavour intensity (P=0.006 and P=0.01 respectively). Dry cured ham samples from pigs fed higher amounts of monounsaturated fatty acids showed a significantly higher consistency fat than those from pigs fed polyunsaturated fatty acids.