Modulatory Effects of Breed, Feeding Status, and Diet on Adipogenic, Lipogenic, and Lipolytic Gene Expression in Growing Iberian and Duroc Pigs.

Meat quality depends on tissue composition which is in turn influenced by different factors, such as diet, genotype, age, or sex. We evaluated the effects of breed, 24 h fasting, and dietary energy source (HO: oleic acid versus CH: carbohydrates) on the expression of candidate genes involved in adipogenesis, lipogenesis, and lipolysis in the adipose tissue from Iberian and Duroc growing pigs. The Iberian pigs showed greater feed intake, backfat thickness, and saturated fatty acids (SFA) content in the subcutaneous fat, whereas the Duroc pigs had greater ham weight and polyunsaturated fatty acids (PUFA) content. In both breeds, the diet induced changes in the fatty acid (FA) composition of subcutaneous fat samples. The HO group had higher monounsaturated fatty acids (MUFA) and oleic acid, and lower SFA than the CH group. Regarding gene expression, breed and feeding status (fasting versus postprandial) had significant effects on gene expression, with quantitative interactions between them, while diet showed negligible effects. In general, adipogenic and lipogenic genes were upregulated in the Iberian pigs and in postprandial samples. In contrast, the expression of lipolytic genes showed complex interaction effects. Our results agree with the phenotypic differences between the Iberian and Duroc breeds and with the inhibition of lipogenesis by fasting. Quantitative interactions between breed and feeding status effects were observed, which indicates a different response to fasting of the two breeds, with the obese Iberian breed showing a more stable expression of lipogenic genes. These results highlight the complexity of lipid metabolism regulation, especially in relation to lipolysis processes.

Longissimus dorsi transcriptome analysis of purebred and crossbred Iberian pigs differing in muscle characteristics.

BACKGROUND: The two main genetic types in Iberian pig production show important phenotypic differences in growth, fattening and tissue composition since early developmental stages. The objective of this work was the evaluation of muscle transcriptome profile in piglets of both genetic types, in order to identify genes, pathways and regulatory factors responsible for their phenotypic differences. Contemporary families coming from pure Iberian pigs (IB) or from crossing with Duroc boars (DU×IB) were generated. Piglets (14 from each genetic type) were slaughtered at weaning (28 days) and longissimus dorsi was sampled for composition and gene expression studies. RNA was obtained and hybridized to Affymetrix Porcine Genechip expression arrays. RESULTS: Loin muscle chemical composition showed significant differences between genetic types in intramuscular fat content (6.1% vs. 4.3% in IB and DUxIB animals, respectively, P = 0.009) and in saturated (P = 0.019) and monounsaturated fatty acid proportions (P = 0.044). The statistical analysis of gene expression data allowed the identification of 256 differentially expressed (DE) genes between genetic types (FDR < 0.10), 102 upregulated in IB and 154 upregulated in DU×IB. Transcript differences were validated for a subset of DE genes by qPCR. We observed alteration in biological functions related to extracellular matrix function and organization, cellular adhesion, muscle growth, lipid metabolism and proteolysis. Candidate genes with known effects on muscle growth were found among the DE genes upregulated in DU×IB. Genes related to lipid metabolism and proteolysis were found among those upregulated in IB. Regulatory factors (RF) potentially involved in the expression differences were identified by calculating the regulatory impact factors. Twenty-nine RF were found, some of them with known relationship with tissue development (MSTN, SIX4, IRX3), adipogenesis (CEBPD, PPARGC1B), or extracellular matrix processes (MAX, MXI1). Correlation among the expression of these RF and DE genes show relevant differences between genetic types. CONCLUSION: These results provide valuable information about genetic mechanisms determining the phenotypic differences on growth and meat quality between the genetic types studied, mainly related to the development and function of the extracellular matrix and also to some metabolic processes as proteolysis and lipid metabolism. Transcription factors and regulatory mechanisms are proposed for these altered biological functions.

Prenatal programming in an obese swine model: sex-related effects of maternal energy restriction on morphology, metabolism and hypothalamic gene expression.

Maternal energy restriction during pregnancy predisposes to metabolic alterations in the offspring. The present study was designed to evaluate phenotypic and metabolic consequences following maternal undernutrition in an obese pig model and to define the potential role of hypothalamic gene expression in programming effects. Iberian sows were fed a control or a 50 % restricted diet for the last two-thirds of gestation. Newborns were assessed for body and organ weights, hormonal and metabolic status, and hypothalamic expression of genes implicated in energy homeostasis, glucocorticoid function and methylation. Weight and adiposity were measured in adult littermates. Newborns of the restricted sows were lighter (P <0·01), but brain growth was spared. The plasma concentration of TAG was lower in the restricted newborns than in the control newborns of both the sexes (P <0·01), while the concentration of cortisol was higher in females born to the restricted sows (P <0·04), reflecting a situation of metabolic stress by nutrient insufficiency. A lower hypothalamic expression of anorexigenic peptides (LEPR and POMC, P <0·01 and P <0·04, respectively) was observed in females born to the restricted sows, but no effect was observed in the males. The expression of HSD11B1 gene was down-regulated in the restricted animals (P <0·05), suggesting an adaptive mechanism for reducing the harmful effects of elevated concentrations of cortisol. At 4 and 7 months of age, the restricted females were heavier and fatter than the controls (P< 0·01). Maternal feed restriction induces asymmetrical growth retardation and metabolic alterations in the offspring. Differences in gene expression at birth and higher growth and adiposity in adulthood suggest a female-specific programming effect for a positive energy balance, possibly due to overexposure to endogenous stress-induced glucocorticoids.

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.

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.

Alleviating Heat Stress in Fattening Pigs: Low-Intensity Showers in Critical Hours Alter Body External Temperature, Feeding Pattern, Carcass Composition, and Meat Quality Characteristics.

Heat stress is a significant environmental problem that has a detrimental impact on animal welfare and production efficiency in swine farms. The current study was conducted to assess the effect of low-intensity showers, provided during critical high-temperature hours daily, on body external temperature, feeding pattern, and carcass and meat quality characteristics in fattening pigs. A total of 400 animals (200 barrows and 200 gilts) were randomly allotted in 40 pens. A shower nozzle was installed over 20 pens (half barrows and half gilts) where pigs received a low-intensity shower for 2 min in 30 min intervals from 12 to 19 h (SHO group). Another group without showers was also considered (CON). Feeder occupancy measurement, thermographic measures, and carcass and meat quality parameters were studied. In the periods with higher environmental temperatures, SHO animals showed an increase in the feeder occupancy rate compared to the CON group. A decrease in temperature was observed after the shower, regardless of the anatomical location (p < 0.005). The treatment with showers led to higher values than in the CON group of 4.72%, 3.87%, 11.8%, and 15.1% for hot carcass weight, lean meat yield, and fat thickness in Longissimus Dorsi (LD) and Gluteus Medius muscles, respectively (p < 0.01). Pork from CON showed a 14.9% higher value of drip loss, and 18.9% higher malondialdehyde concentration than SHO (p < 0.01); meanwhile, intramuscular fat content was 22.8% higher in SHO than in CON (p < 0.01). On the other hand, the CON group exhibited higher L* (2.13%) and lower a* and b* values (15.8% and 8.97%) compared to the SHO group. However, the pH20h of the CON group was significantly lower than that of the SHO group (p < 0.001), indicating a softer pH decrease. Related to fatty acids in subcutaneous outer and inner layers and intramuscular fat, the CON group showed higher ΣSFA and lower ΣMUFA and Δ9-desaturase indexes than SHO (p < 0.05). In conclusion, the amelioration of heat stress through showers at critical times should be considered an interesting tool that improves both carcass and meat quality, as well as animal welfare.

Correction: Gómez et al. Long-Term Effect of Maternal Antioxidant Supplementation on the Lipid Profile of the Progeny According to the Sow's Parity Number. Antioxidants 2024, 13, 379.

In the original publication [...].

Long-Term Effect of Maternal Antioxidant Supplementation on the Lipid Profile of the Progeny According to the Sow's Parity Number.

Pig feeding prior to the extensive fattening phase might affect the final lipid profile and product quality. This study evaluates how maternal supplementation with vitamin E (VITE) (100 mg/kg), hydroxytyrosol (HXT) (1.5 mg/kg), or combined administration (VE + HXT) affects the piglet's plasma and tissues' fatty acid profiles and lipid stability according to the sow's parity number (PN), as well as the possible changes to the lipid profile after extensive feeding. The sows' PN affected the total fatty acid profile of plasma, muscle, and liver of piglets, with lower Δ-9 and Δ-6 desaturase indices but higher Δ-5 in those from primiparous (P) than multiparous (M) sows. Dietary VITE was more effective at decreasing C16:0 and saturated fatty acids in the muscle of piglets born from M than P sows, and modified the liver phospholipids in a different way. Sows' supplementation with HXT increased C18:2n-6 in triglycerides and polyunsaturated fatty acids (PUFA) in muscle phospholipids. In the liver, HXT supplementation also increased free-PUFA and free-n-3 fatty acids. However, lipid oxidation of piglets' tissues was not affected by the antioxidant supplementation, and it was higher in the livers of piglets born from M sows. The fatty acid profile in the muscle of pigs after extensive feeding was not affected by the PN, but it was by the sows' antioxidant supplementation, with positive effects on quality by both compounds.

Maternal dietary antioxidant supplementation regulates weaned piglets' adipose tissue transcriptome and morphology.

Antioxidant supplementation in critical periods may be useful for improvement of piglet early viability and development. We have evaluated the effects of maternal perinatal diet inclusion of a high vitamin E level (VE, 100 mg all-rac-α-tocopheryl acetate /kg), hydroxytyrosol (HT, 1.5 mg/kg), or their combination (VEHT), in comparison to a control diet (C, 30 mg all-rac-α-tocopheryl acetate /kg), on the offspring homeostasis and metabolism, analysing the weaned piglets' adipose tissue transcriptome and adipocyte morphology. Diets were provided to pregnant Iberian sows (n = 48, 12 per treatment) from gestation day 85 to weaning (28 days postpartum) and 48 piglets (n = 12 per treatment) were sampled 5 days postweaning for dorsal subcutaneous adipose tissue analyses. RNA obtained from 6 animals for each diet was used for paired-end RNA sequencing. Results show that supplementation of sows' diet with either vitamin E or hydroxytyrosol had substantial effects on weaned piglet adipose transcriptome, with 664 and 587 genes being differentially expressed, in comparison to C, respectively (q-value<0.10, Fold Change>1.5). Genes upregulated in C were mainly involved in inflammatory and immune response, as well as oxidative stress, and relevant canonical pathways and upstream regulators involved in these processes were predicted as activated, such as TNF, IFNB or NFKB. Vitamin E, when supplemented alone at high dose, activated lipid biosynthesis functions, pathways and regulators, this finding being accompanied by increased adipocyte size. Results suggest an improved metabolic and antioxidant status of adipose tissue in animals born from sows supplemented with individual antioxidants, while the combined supplementation barely affected gene expression, with VEHT showing a prooxidant/proinflamatory functional profile similar to C animals. Different hypothesis are proposed to explain this unexpected result. Findings allow a deeper understanding of the processes taking place in adipose tissue of genetically fat animals and the role of antioxidants in the regulation of fat cells function.

Short- and Long-Term Effects of Split-Suckling in Pigs According to Birth Weight.

Forty-eight litters were used, with a total number of 645 piglets involved in the study. The split-suckling technique was applied to half of the litters at the end of farrowing by removing the heaviest piglets over three periods of 1 h. The piglets were individually weighed at 0, 1 d, and at weaning. Piglet losses were recorded daily. Traceability was maintained until the carcass splitting and meat analysis took place. Carcasses were eviscerated and weighed individually. Total mortality at weaning was affected by body weight, where the low-body-weight piglets showed a mortality rate almost four times higher than that of the normal-weight piglets. Mortality was highest in the first days of life, especially in the low-body-weight piglets. At weaning, split-suckling treatment caused a slight increase in mortality compared to the control group piglets (25% vs. 17.1%). Split-suckling had a positive effect on weight gain during the first 24 h of life (p = 0.014), and there was an interaction between treatment and parity (p = 0.007), with split-suckling being more effective in the primiparous sows compared to the multiparous sows. The piglets from litters receiving the split-suckling treatment had a lower average daily gain during the lactation period (p < 0.001) than the piglets from the control group. Weight gain during the first 24 h of life of the piglets subjected to split-suckling was higher than those of the control group. A lower IgG and α-tocopherol in plasma in the heavier piglets subjected to split-suckling treatment was observed in comparison to their respective control. The piglets from litters receiving the treatment showed a lower average daily gain during the lactation period (p < 0.001) than the piglets from the control group. No difference in slaughter weight was observed according to treatment. The pigs which received split-suckling treatment showed lower subcutaneous fat thickness (p < 0.0013) and higher lean meat yield (p < 0.0027), this effect being more marked in pigs from primiparous sows. Intramuscular fat concentration was higher in the Longissimus Dorsi muscle of the low-body-weight piglets. In the pigs that received split-suckling treatment, a higher concentration of C18:3n-3 (p = 0.036) and a tendency towards a higher concentration of C18:2n-6 (p = 0.107) and unsaturation index (p = 0.113) was observed in intramuscular fatty acids at slaughter, together with a lower concentration of C16:0 (p = 0.053) and SFA (p = 0.064). In conclusion, long-term response to split-suckling, particularly in low-birth-weight piglets, suggests an alteration in adiposity and metabolic regulation in these piglets that receive high levels of colostrum.

Maternal Supplementation of Vitamin E or Its Combination with Hydroxytyrosol Increases the Gut Health and Short Chain Fatty Acids of Piglets at Weaning.

An adequate intestinal environment before weaning may contribute to diarrhea predisposition and piglet development. This study evaluates how the dietary supplementation of vitamin E (VE) (100 mg/kg), hydroxytyrosol (HXT) (1.5 mg/kg) or the combined administration (VE + HXT) given to Iberian sows from gestation affects the piglet's faecal characteristics, short chain fatty acids (SCFAs), fatty acid profile or intestinal morphology as indicators of gut health; and quantify the contribution of the oxidative status and colostrum/milk composition to the piglet's SCFAs content and intestinal health. Dietary VE increased isobutyric acid (iC4), butyric acid (C4), isovaleric acid (iC5), and ∑SCFAs, whereas HXT increased iC4 and tended to decrease ∑SCFAs of faeces. Piglets from HXT-supplemented sows also tended to have higher faecal C20:4n-6/C20:2 ratio C22:6 proportion and showed lower occludin gene expression in the duodenum. The combination of both antioxidants had a positive effect on iC4 and iC5 levels. Correlation analyses and regression equations indicate that faecal SCFAs were related to oxidative status (mainly plasma VE) and colostrum and milk composition (mainly C20:2, C20:3, C20:4 n-6). This study would confirm the superiority of VE over HXT supplementation to improve intestinal homeostasis, gut health, and, consequently piglet growth.

Different Effect of Vitamin E or Hydroxytyrosol Supplementation to Sow's Diet on Oxidative Status and Performances of Weaned Piglets.

Different feeding strategies are being applied to sows in order to obtain homogeneous piglets' weights and improved health status. This study evaluated how the dietary supplementation of vitamin E (VE) (100 mg/kg), hydroxytyrosol (HXT) (1.5 mg/kg) or the combined administration (VE + HXT) given to Iberian sows from day 85 of gestation affected the growth pattern of the piglets and their oxidative status; and quantified what these effects were due to. Dietary VE and HXT improved the oxidative status of sows and piglets. Both VE and HXT modified the growth pattern at birth and performances of the piglets in a different way according to the growing period. Piglets' performances were positively correlated with plasma VE and negatively with plasma malondialdehyde (MDA) of the sow. However, the highest variation in growth patterns was explained by the colostrum composition. Significant linear equations were observed between piglets' performances and colostrum saturated (SAT), n-7 monounsaturated fatty acids (C16:1n-7 and C18:1n-7) and different desaturases indices. This study would confirm that VE supplementation to the sow diet could be more adequate than HXT for the improved development during the first weeks of a piglet's life. The combined administration of both antioxidants would not produce additional positive effects compared to the individual supplementation.

Dietary Vitamin E and/or Hydroxytyrosol Supplementation to Sows during Late Pregnancy and Lactation Modifies the Lipid Composition of Colostrum and Milk.

Modifying the composition of a sow's milk could be a strategy to improve the intestinal health and growth of her piglet during the first weeks of life. This study evaluated how dietary supplementation of vitamin E (VE), hydroxytyrosol (HXT) or VE+HXT given to Iberian sows from late gestation affected the colostrum and milk composition, lipid stability and their relationship with the piglet's oxidative status. Colostrum from VE-supplemented sows had greater C18:1n-7 than non-supplemented sows, whereas HXT increased polyunsaturated (∑PUFAs), ∑n-6 and ∑n-3 fatty acids. In 7-day milk, the main effects were induced by VE supplementation that decreased ∑PUFAs, ∑n-6 and ∑n-3 and increased the Δ-6-desaturase activity. The VE+HXT supplementation resulted in lower desaturase capacity in 20-day milk. Positive correlations were observed between the estimated mean milk energy output and the desaturation capacity of sows. The lowest concentration of malondialdehyde (MDA) in milk was observed in VE-supplemented groups, whereas HXT supplementation increased oxidation. Milk lipid oxidation was negatively correlated with the sow's plasma oxidative status and to a great extent with the oxidative status of piglets after weaning. Maternal VE supplementation produced a more beneficial milk composition to improve the oxidative status of piglets, which could promote gut health and piglet growth during the first weeks, but more research is needed to clarify this.

Short- and Long-Term Effects of Birth Weight and Neonatal Care in Pigs.

Swine industries worldwide face a loss in profit due to high piglet mortality, particularly as a consequence of the marked increase in prolificity and low birth weight (BW) of piglets. This research studied the effect of BW and individual neonatal care provided to piglets on preweaning mortality, and the long-term effects on growth and carcass and meat characteristics. Litters from seventy-one crossbred sows (PIC 34) were included in the trial. Half of each litter did not receive any further management, and the remaining half received the pre-established management protocol of early assistance of neonatal care (NC). Along lactation, the low-BW piglets (weight equal to or less than 1.1 kg) showed a threefold higher mortality rate than piglets of higher weights (32 vs. 10%; p = 0.001), with mortality particularly concentrated within the first week after birth. No effect of NC treatment was observed on mortality ratio caused by crushing, but a significant effect was observed in low-BW piglets who died of starvation (p < 0.01). The effect of NC on growth is dependent on BW, and heavier piglets at birth benefit from NC treatment to a higher extent than low-BW piglets. Low-BW piglets showed a higher fatness (p = 0.003), lower lean cut yield (p = 0.002) in carcasses, and higher intramuscular fat (IMF) content (2.29% vs. 1.91%; p = 0.01) in meat. NC treatment increased the lean content in carcasses from low-BW piglets (p < 0.01). The monounsaturated fatty acids concentration was higher in lower-than-normal-BW piglets (48.1% vs. 47.1%; p = 0.002) and the opposite effect was observed for polyunsaturated fatty acids (13.6% vs. 15.7%; p = 0.002). NC treatment induced a higher concentration of n-7 fatty acids. In conclusion, NC treatment may be a useful practice to reduce mortality in low-BW piglets. Moreover, NC could affect carcass fatness and meat quality, thus suggesting a long-term effect on metabolism.

Free-Range Feeding Alters Fatty Acid Composition at the sn-2 Position of Triglycerides and Subcutaneous Fat Physicochemical Properties in Heavy Pigs.

The nutritional value of fat consumption depends on both the fatty acid composition and the positional distribution of fatty acids within the triglyceride molecule. This research studies the effect of feeding with three different diets (4% lard-enriched; 11.5% high-oleic sunflower-enriched; and extensive feeding mainly with acorns) on the composition of fatty acids in the sn-2 position (and sn-1,3) of triglycerides and the textural properties of subcutaneous fat in heavy Iberian pigs (n = 210 castrated males). A moderate dietary enrichment with oleic acid in mixed diets did not alter the regulation of the sn-2 position of triglyceride (69.9% and 13.9% of palmitic and oleic acids, respectively), but the extremely high intake of oleic acid in pigs fed mainly on acorns changed the proportions of palmitic and oleic acids at the sn-2 position in the subcutaneous fat of pigs (55.0% and 27.2%, respectively). Hardness, adhesiveness, cohesiveness, gumminess, and chewiness showed the least values in EXT pigs, and the greatest values in LARD-fed barrows. SUN cohesiveness and gumminess did not differ from those fed LARD. In addition, Iberian pigs raised in free-range conditions had a more favorable nutritional lipid profile for human health compared to pigs fed conventional diets.

Influence of genetic background and dietary oleic acid on gut microbiota composition in Duroc and Iberian pigs.

BACKGROUND: Phenotypic variability for productive and meat quality traits has been largely studied in Iberian pigs, especially in genetic selection and nutritional experiments. Complex interactions among genetic background, diet composition and gut microbiota hinder the correct assessment of each factor's contribution on phenotypes. In order to disentangle these interactions, we evaluated changes in gut microbiota composition comparing 48 Iberian and Duroc pigs fed diets with different energy source (standard diet with carbohydrates vs sunflower oil-enriched diet with high oleic acid content). RESULTS: A higher richness was observed for Iberian pigs (p < 0.05) and compositional analysis was applied for beta-diversity, differential abundance and pairwise log-ratio analyses. We found significant differences in overall microbiota composition between breeds, and also between diets inside breeds, to a lesser extent. Differential abundance analysis revealed that Duroc animals have more proportion of Actinobacteria and Prevotella, while Iberian replace those microorganisms with other more variable taxa. According to dietary differences, high-oleic fed animals were richer in Prevotella. We also found microbial ratios capable of separating animals by breeds and diets, mostly related to Actinobacteria. CONCLUSION: This study reveals that both genetic background and diet composition might have a relevant impact in gut microbiota composition. The application of compositional data analysis has facilitated the identification of microorganisms and ratios as possibly related to metabolic changes due to genetic background and, to a lower extent, to dietary changes. This may lead to a relevant progress in the knowledge of interactions between pig genetics, environment and gut microbiota.

Changes in Biceps femoris Transcriptome along Growth in Iberian Pigs Fed Different Energy Sources and Comparative Analysis with Duroc Breed.

This experiment was conducted to investigate the effects of developmental stage, breed, and diet energy source on the genome-wide expression, meat quality traits, and tissue composition of biceps femoris muscle in growing pure Iberian and Duroc pigs. The study comprised 59 Iberian (IB) and 19 Duroc (DU) animals, who started the treatment at an average live weight (LW) of 19.9 kg. The animals were kept under identical management conditions and fed two diets with different energy sources (6% high oleic sunflower oil or carbohydrates). Twenty-nine IB animals were slaughtered after seven days of treatment at an average LW of 24.1 kg, and 30 IB animals plus all the DU animals were slaughtered after 47 days at an average LW of 50.7 kg. The main factors affecting the muscle transcriptome were age, with 1832 differentially expressed genes (DEGs), and breed (1055 DEGs), while the effect of diet on the transcriptome was very small. The results indicated transcriptome changes along time in Iberian animals, being especially related to growth and tissue development, extracellular matrix (ECM) composition, and cytoskeleton organization, with DEGs affecting relevant functions and biological pathways, such as myogenesis. The breed also affected functions related to muscle development and cytoskeleton organization, as well as functions related to solute transport and lipid and carbohydrate metabolism. Taking into account the results of the two main comparisons (age and breed effects), we can postulate that the Iberian breed is more precocious than the Duroc breed, regarding myogenesis and muscle development, in the studied growing stage.

Effects of L-Glutamine Supplementation during the Gestation of Gilts and Sows on the Offspring Development in a Traditional Swine Breed.

The use of amino acids during pregnancy, such as glutamine (Gln), seems to be a promising strategy in selected swine breeds to improve the offspring prenatal development. The main goal of the current study was to assess the development of the offspring from parity 1-3 sows of a traditional breed, which were supplemented with 1% glutamine after Day 35 of gestation, under farm conditions. A total of 486 (288 treated) piglets from 78 (46 treated) Iberian sows were used. At birth and slaughterhouse, fatty acid composition, metabolism, and mTOR pathway gene expression were analyzed. At birth, treated newborns showed greater amounts of specific amino acids in plasma, such as glutamine, asparagine, or alanine, and Σn-3 fatty acids in cellular membranes than control newborns. The expression of genes belonging to mTOR Complex 1 was also higher in treated piglets with normal birth-weight. However, these findings did not improve productive traits at birth or following periods in litters from supplemented gilts (parity 1) or sows (parities 2-3). Thus, further research is needed to properly understand the effects of prenatal glutamine supplementation, particularly in traditional swine breeds.

Breed, Diet, and Interaction Effects on Adipose Tissue Transcriptome in Iberian and Duroc Pigs Fed Different Energy Sources.

In this study, we analyzed the effects of breed, diet energy source, and their interaction on adipose tissue transcriptome in growing Iberian and Duroc pigs. The study comprised 29 Iberian and 19 Duroc males, which were kept under identical management conditions except the nutritional treatment. Two isoenergetic diets were used with 6% high oleic sunflower oil (HO) or carbohydrates (CH) as energy sources. All animals were slaughtered after 47 days of treatment at an average live weight of 51.2 kg. Twelve animals from each breed (six fed each diet) were employed for ham subcutaneous adipose tissue RNA-Seq analysis. The data analysis was performed using two different bioinformatic pipelines. We detected 837 and 1456 differentially expressed genes (DEGs) according to breed, depending on the pipeline. Due to the strong effect of breed on transcriptome, the effect of the diet was separately evaluated in the two breeds. We identified 207 and 57 DEGs depending on diet in Iberian and Duroc pigs, respectively. A joint analysis of both effects allowed the detection of some breed-diet interactions on transcriptome, which were inferred from RNA-Seq and quantitative PCR data. The functional analysis showed the enrichment of functions related to growth and tissue development, inflammatory response, immune cell trafficking, and carbohydrate and lipid metabolism, and allowed the identification of potential regulators. The results indicate different effects of diet on adipose tissue gene expression between breeds, affecting relevant biological pathways.

Changes in the fatty acid profile of the subcutaneous fat of swine throughout fattening as affected by dietary conjugated linoleic acid and monounsaturated fatty acids.

The fatty acid profile of the subcutaneous fat of pigs and its evolution throughout fattening as affected by dietary conjugated linoleic acid (CLA), monounsaturated fatty acids (MUFA), and their interaction (CLAxMUFA) were studied. Three levels (0, 1, and 2%) of an enriched CLA oil (28% cis-9, trans-11 and 28% trans-10, cis-12 CLA) were combined with two levels of MUFA (low, 19% average; and high, 39% average) for pig feeding (288 gilts). Subcutaneous shot-biopsies were taken from 48 animals at the beginning of the trial (S1, 70 kg), 14 days later (S2, 80 kg), and at slaughter (S3, 107 kg). Inclusion of CLA in the diet caused an increase during fattening in cis-9, trans-11 CLA, trans-10, cis-12 CLA, and saturated fatty acids (SFA) contents of pig backfat and a decrease in MUFA and polyunsaturated fatty acids (PUFA). MUFA supplementation also led to a MUFA enrichment of backfat. The interaction CLAxMUFA affected the SFA content. The rates of accumulation of CLA isomers, SFA, and MUFA throughout the trial did not follow a linear behavior, such rates being higher from S1 to S2 than from S2 to S3. These rates were also influenced by dietary CLA and MUFA levels. The increase in the ratio of saturated to unsaturated fatty acids of backfat caused by dietary CLA might be balanced by supplementation of pig diets with MUFA.