Backfat Fatty Acid Research Articles

THE EFFECT OF COCONUT OIL INTAKE ON THE MEAT FATTY ACID PROFILE OF PIGS

The article deals with the effect of adding coconut oil to the diet of heavy pigs on the concentration of fatty acids in leg meat, back fat, and liver. Lauric acid has several positive effects on the consumer. However, the concentration of this fatty acid in pig meat is very low or absent. Coconut oil, which contains a high concentration of lauric acid, was added to the pigs´ diet (30 g per head per day) for 18 days before slaughtering. This dietary intervention increased the concentration of lauric acid in leg meat and back fat but had no effect on the lauric acid concentration in pig liver. Concentrations of margaric and arachidic acids in leg meat, oleic, arachidic, and sum of mono-unsaturated fatty acids in back fat, palmitoleic and sum of saturated fatty acids in pig liver were affected by the addition of coconut oil to the diet of pigs. The monounsaturation index C18:1/C18:0 in leg meat was higher in the coconut oil group. The intake of small amounts of coconut oil affected the concentration of some fatty acids and increased the concentration of lauric acid in the leg meat and back fat of pigs.

Effect of protein-restricted diet during growing period on performance and carcass quality traits of Duroc x Iberian crossbred barrows under different management conditions

This study investigated the effects of feeding protein-restricted diets during the growing period on performance and carcass quality traits of Duroc (boars) x Iberian (sows) crossbred pigs slaughtered at commercial weight for local pig production. Two trials were conducted in different management conditions, with 28 and 33 barrows, respectively. In each trial, pigs were divided into two dietary groups, one group received a control diet (CD, 16.5 % crude protein, CP) and the other one was fed a protein restricted diet (PRD_1 for Trial 1: 12.4 % CP; and PRD_2 for Trial 2: 10.0 % CP). At 100 kg of body weight (BW), five pigs per group and trial were slaughtered, while the remaining pigs were fattened on a standard finishing diet until reaching 160 kg BW before slaughter. No significant changes in growth, carcass and ham composition or backfat thickness due to decreased protein supply during the growing period were observed. However, the intramuscular fat content increased in Longissimus thoracis et lumborum (LTL) and ham muscles of PDR_2 pigs. Furthermore, the backfat fatty acid (FA) profile presented higher proportion of oleic and monounsaturated FAs in pigs fed PRD diets, while polyunsaturated FA decreased in PDR_2 pigs. The PRD_1 group exhibited higher redness and thawing water loss in LTL, while PDR_2 group showed greater redness, yellowness and thawing water loss values compared to the CD group. Overall, the results indicate that feeding protein-restricted diets during growing period did not have a substantial impact on growth or meat quality. The success of implementing such diets may be influenced by factors such as the protein restriction level and the animal management conditions.

Pork Fat and Meat: A Balance between Consumer Expectations and Nutrient Composition of Four Pig Breeds.

Food fat content is one of the most controversial factors from a consumer's point of view. Aim: (1) The trends in consumer attitudes towards pork and the fat and meat compositions in Duroc and Altai meat breeds and Livny and Mangalitsa meat and fat breeds were studied. (2) Methods: Netnographic studies were used to assess Russian consumer purchasing behavior. Protein, moisture, fat, backfat fatty acid content from pigs, longissimus muscles, and backfat from (A) Altai, (L) Livny, and (M) Russian Mangalitsa breeds were compared with those from (D) Russian Duroc. Raman spectroscopy and histology were applied to the backfat analysis. (3) Results: The attitude of Russian consumers to fatty pork is contradictory: consumers note its high fat content as a negative factor, but the presence of fat and intramuscular fat is welcomed because consumers positively associate them with better taste, tenderness, flavor, and juiciness. The fat of the 'lean' D pigs did not show a "healthy" fatty acid ratio, while the n-3 PUFA/n-6 PUFA ratio in the fat of the M pigs was the best, with significant amounts of short-chain fatty acids. The highest UFA content, particularly omega 3 and omega 6 PUFA, was found in the backfat of A pigs with a minimum SFA content. The backfat of L pigs was characterized by a larger size of the adipocytes; the highest monounsaturated and medium chain fatty acid contents and the lowest short-chain fatty acid content; the ratio of omega 3 to omega 6 was 0.07, and the atherogenicity index in L backfat was close to that of D, despite the fact that D pigs are a meat type, while L pigs are a meat and fat type. On the contrary, the thrombogenicity index in L backfat was even lower than the D one. (4) Conclusions: Pork from local breeds can be recommended for functional food production. The requirement to change the promotion strategy for local pork consumption from the position of dietary diversity and health is stated.

Inclusion of olive by-products in growing diets causes minor effects on meat quality of Iberian pigs fattened in a traditional system

Aim of study: To evaluate two experimental diets based on olive cake supplied during the growth period as an alternative to the restricted feeding applied in the production of Iberian pigs fattened with acorn (Montanera system). Area of study: Southwest of Badajoz, Spain Material and methods: 44 Iberian pigs were divided in three diet groups: 1) control (C) group (n=15), 2) dry olive pulp (DOP) group, fed a compound feed elaborated with olive pulp (n=14), and 3) wet crude olive cake (WCOC) group, fed a compound feed and olive cake silage supplied ad libitum (n=15). Subcutaneous fat biopsies were taken and backfat thickness and longissimus thoracis et lumborum (LTL) area were measured. In addition, quality traits (intramuscular fat percentage, color, pigment content, water holding capacity and shear force) were measured in LTL. Backfat fatty acid profile and intramuscular fat were also analysed. Main results: Significant differences were observed between groups for most of the fatty acids in backfat at 95 kg but differences were of lower magnitude at 160 kg and affected only to C16:1, C18:0, C18:1, C20:0, C20:1 and ΣSFA. Otherwise, lower values for red color and myoglobin content and higher for thawing water losses were observed for DOP pigs. The WCOC did not affect the analysed quality traits. Research highlights: Experimental diets did not have an important impact on growth, carcass composition or meat quality. Therefore, WCOC dietary treatment could be an interesting alternative that could reduce the undesirable effects of feed restriction.

Finishing season and feeding resources influence the quality of products from extensive-system Gascon pigs. Part 1: Carcass traits and quality of fresh loin

Consumers perceive pork products from local breeds reared in extensive systems positively because of their specific quality properties and regional identity. The sensory, nutritional and technological qualities of these products depend, among other things, on pig production, especially its climatic conditions and the availability of feed resources, which can influence traits of muscle and fat tissue. The present study (part 1) was part of a larger project that assessed the influence of the finishing season and feeding resources on carcass and tissue traits and the quality of meat and dry-cured ham from Gascon pigs in an extensive system. Following the specifications of the Protected Designation of Origin “Noir de Bigorre”, castrated Gascon males were reared on rangelands (grassland and forest areas) and received a supplementary diet from 5 to 6 months of age until slaughter at a minimum of 12 months of age and ca. 170 kg live weight. Three finishing seasons were considered as follows: Winter (n = 18), Spring (n = 22) and Autumn (n = 23). To estimate specific effects of season on productive and quality traits and avoid bias due to effects of genes known to influence these traits, polymorphisms in the RYR1, PRKAG3, MC4R and LEPR genes were included in the analysis models. The finishing season did not influence growth rate. Compared to Winter pigs, Spring and Autumn pigs had slightly lower carcass fatness (P < 0.05), higher ultimate pH and redder and darker color of the Longissimus muscle (LM) (P < 0.01). Loin drip loss was low overall, but was higher for Spring pigs, whereas cooking loss and shear force were similar among seasons. Spring pigs tended to have the lowest LM lipid content, whereas LM myoglobin content remained unaffected. Autumn pigs had lower potential of lipid oxidation in LM than Winter and Spring pigs (P < 0.01), but muscle metabolic traits assessed via glycolytic and oxidative enzyme activities did not differ among seasons. The finishing season modified the backfat fatty acid (FA) profile, with a lower polyunsaturated FA percentage in Autumn pigs than Winter or Spring pigs (P < 0.001), even though the saturated and monounsaturated FA percentages did not differ. In particular, Spring pigs had the lowest n-6:n-3 and C18:2:C18:3 ratios (P < 0.001), as a result of grazing. Overall, Spring and Autumn finishing seasons seem more favorable to technological and sensory pork attributes, with an additional positive effect of Spring finishing on pork nutritional value.

Efficacy of corn dried distillers grains with solubles as a replacement for soybean meal in Boer-cross goat finishing diets

Due to increased use of dried distillers grains with solubles (DDGS) in animal feed and accessibility of ethanol plants in the Midwest, the effect of feeding DDGS in place of soybean meal (SBM) on growth, economics, carcass characteristics, backfat fatty acid profiles, and fecal microbiome of Boer-cross goats was evaluated. Forty-eight Boer-cross goats (approximately 70 d of age; 28.21 ± 0.96 kg) were blocked by BW and assigned to 1 of 4 dietary treatments in a completely randomized design. Treatments were 0 %, 33 %, 66 %, or 100 % DDGS replacing SBM, equating to the inclusion of 0 % (0DDGS), 10.3 % (10DDGS), 20.5 % (20DDGS), or 31.1 % (30DDGS) DDGS in the total diet. The inclusion rates of corn and soybean hulls were adjusted to maintain isocaloric and isonitrogenous diets. Goats were provided ad libitum access to feed and water for 47 d. There were 3 goats/pen and 4 pens/treatment. The inclusion of DDGS linearly improved (P = 0.01) average daily gain (ADG) and gain:feed (G:F; P = 0.001), without affecting average daily feed intake (ADFI; P > 0.10) in goats fed DDGS in place of SBM. Feed cost/kg gain decreased (P < 0.0001) with increased inclusion of DDGS, which led to a linear increase in value of gain (P = 0.02) with increased DDGS inclusion. Bacterial and archaeal genera with individual relative abundances greater than 1% in feces that were impacted by 30DDGS were increased Ruminococcus and Methanobrevibacter (P < 0.01) and decreased Lachnoclostridium (P = 0.02). Ruminococcus and Methanobrevibacter most likely increased in goats fed 30DDGS due to greater amounts of soluble fiber passing through the rumen, thus being fermented in the hindgut. While there were no differences detected in overall percentage of phyla Bacteroidetes (P = 0.36) and Firmicutes (P = 0.12) among treatments; the Firmicutes:Bacteroidetes was greater (P = 0.05) in goats fed 30DDGS than those fed 0DDGS. There was no observed impact (P = 0.47) of treatment on β-diversity, although Shannon Index tended to increase (P = 0.09) in goats fed 30DDGS possibly because more soluble fiber was available for fermentation in the hindgut. Polyunsaturated fatty acids over the 12th rib tended to increase quadratically (P = 0.06) with increased DDGS inclusion, yet there was no differences observed in the saturated fatty acid to unsaturated fatty acid ratio (P = 0.93) or iodine value (P = 0.36) with increased levels of DDGS. Up to 100 % of the SBM in a Boer-cross finishing goat ration can be replaced by corn DDGS with no detectable difference in growth performance, fecal microbial populations, carcass characteristics, or fatty acid profile.

Effect of chromium yeast supplementation on lipid profile of swine fat.

This study was conducted to evaluate the period of chromium yeast supplementation on lipid profile of backfat and Longissimus lumborum muscle of barrows. It was evaluated carcass samples from forty barrows, genetically similar. Pigs diets were supplemented with 0.4 mg kg-1 of chromium yeast in four periods (0, 38, 62 and 94 days before slaughter). The experimental design was completely randomized with four treatments, ten replicates, and each experimental unit consisting of one animal. Lipid profiles of backfat and Longissimus lumborum muscle were analyzed by gas chromatography. The increase in the period of chromium yeast use had a quadratic effect (P<0.05) for stearic and oleic fatty acids, and total saturated, monounsaturated and unsaturated fatty acids in backfat. DH-γ-linolenic and arachidonic fatty acids reduced when the period of chromium yeast use increased. In the meat, there was a quadratic effect (P<0.05) only in the γ-linoleic fatty acid. The use of chromium yeast for different periods influences the lipid profile of the backfat and the Longissimus lumborum muscle, with less effect in the meat.

Relationships between EUROP carcass grading and backfat fatty acid composition in Italian Large White heavy pigs

The amount and quality of covering adipose tissue affect the suitability of hind legs for the production of high-quality seasoned hams. To date, no studies exist on the correlation between EUROP carcass classification and backfat fatty acid (FA) composition in heavy pigs used for dry-cured hams. A sample of 898 Italian Large White heavy pigs was used to verify the relationship between carcass classification based on lean meat percentage and backfat FA composition. A Canonical Discriminant Analysis (CDA) was used to verify the power of individual FA and FA categories in discriminating among EUROP classes. The results proved that saturated FAs (i.e. palmitic, stearic and arachidic acids) and the n-6 polyunsaturated FAs have the highest discriminating power, thus permitting to differentiate among E, U, R, O carcass classes. For the first time, this work demonstrates the relationship between EUROP pig carcass grading, which is only based on an estimate of the percentage of lean meat, and backfat FA composition.

Association study between backfat fatty acid composition and SNPs in candidate genes highlights the effect of FASN polymorphism in large white pigs

The objective of the study was to test the associations between backfat fatty acid composition (FAC) in a sample of 536 Italian Large White pigs and single nucleotide polymorphisms (SNPs) located in candidate genes, using univariate and multivariate approaches. The strongest associations were identified for the SNP AY183428 c.265T>C in Fatty acid synthase (FASN) gene, with the T allele linked to lower backfat contents of stearic (P = 0.003) and arachidic (P < 0.0001) acids, and increased amounts of dihomo-γ-linolenic (P = 0.003) and arachidonic (P = 0.009) acids. These associations were in agreement with the results of a multivariate analysis performed on backfat FAC, and an in silico analysis of the sequence flanking FASN SNP suggested that the T allele may disrupt a putative exonic splicing enhancer sequence therefore possibly affecting FASN activity. If the results will be further confirmed, the studied FASN SNP could be of particular interest for better understanding the regulative patterns controlling porcine backfat FAC.

Programa de selección genética enfocada en la calidad de cerdos Ibéricos puros de montanera

Selection programs are not frequent in the extensive Iberian porcine sector. The traditional company of Iberian pig products located in Jabugo (Sierra de Huelva), Sanchez Romero Carvajal (SRC), with the collaboration and assessment of the Animal Breeding Department of INIA, is making since the year 2012 an unusual effort to develop and implement a breeding selection scheme focused on the Iberian purebred products labelled as Bellota. The animals involved in this program belong to one herd which is placed in two different farms, Montecastilla and Tejarejo (La Granada de Riotinto). 1,205 animals of known pedigree were controlled for selection of growth, body composition, meat and fat quality traits. The main registered traits were average daily gain in montanera, slaughter and carcass weight and weight of premium cuts (ham, shoulders and loins). Besides, backfat fatty acid profile and quality traits as intramuscular fat percentage, color, thawing and cooking water loss and shear force were measured in loin as quality traits. Breeding values for these traits were estimated using an Animal model. Genetic predictions for maternal traits (number of piglets born alive and litter weight at weaning) were performed also using Animal models. Data from 5,134 litters born in 88 batches of 1456 dams and 22 sires were used. This information allowed estimating heritability and genetic correlation as well as to build a combined index for each trait weighting the breeding values by their corresponding economic values. In addition to this, molecular genetic studies on some of the traits cited above are also being implemented. These studies will allow increasing the efficiency of the conventional selection program in the future.

Association study highlights the influence of ELOVL fatty acid elongase 6 gene region on backfat fatty acid composition in Large White pig breed

Dietary fatty acid (FA) composition has an impact on human health. There is an increasing request from consumers for healthier food and pork industry must respond to it without worsening performance and the technological properties of pork products. The inclusion of genetic markers for carcass FA composition in pig selection schemes could be a useful tool to reach the right balance between unsaturated and saturated FAs to satisfy market demands. With the aim of finding genomic regions associated with porcine backfat FA composition, a genome-wide association study was performed on 798 Italian Large White pigs genotyped using Illumina PorcineSNP60 k. The strongest associations with backfat contents of palmitic, palmitoleic, oleic, medium-chain and long-chain FAs were found for the Sus scrofa chromosome (SSC) 8 region located at 119 to 122 Mb, where the gene ELOVL FA elongase 6 is mapped. Palmitic, palmitoleic, stearic and oleic acid contents were also found associated with SSC14, in particular with the genomic region at 121 to 124 Mb, where stearoyl-CoA desaturase Δ9 gene lies. On the other hand, the genomic regions associated with backfat contents of arachidic, arachidonic, n-6 and n-3 FAs showed to harbour mainly genes involved in dietary lipids and carbohydrates digestion, absorption and utilisation. To our knowledge, this is the first study performed in Large White pigs identifying markers and genomic regions associated with backfat FA composition. The results validate in Large White some associations previously detected in other pig breeds and indicate the involvement of distinct metabolic pathways in the deposition pattern of essential and non-essential FAs.

Fatty acid composition of maize silages from different hybrids

Fatty acid composition of maize silages from different hybrids

Genome-wide association study confirm major QTL for backfat fatty acid composition on SSC14 in Duroc pigs

BackgroundFatty acid composition contributes importantly to meat quality and is essential to the nutritional value of the meat. Identification of genetic factors underlying levels of fatty acids can be used to breed for pigs with healthier meat. The aim of this study was to conduct genome-wide association studies (GWAS) to identify QTL regions affecting fatty acid composition in backfat from the pig breeds Duroc and Landrace.ResultsUsing data from the Axiom porcine 660 K array, we performed GWAS on 454 Duroc and 659 Landrace boars for fatty acid phenotypes measured by near-infrared spectroscopy (NIRS) technology (C16:0, C16:1n-7, C18:0, C18:1n-9, C18:2n-6, C18:3n-3, total saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids). Two QTL regions on SSC4 and SSC14 were identified in Duroc for the de novo synthesized fatty acids traits, whereas one QTL on SSC8 was detected in Landrace for C16:1n-7. The QTL region on SSC14 has been reported in previous studies and a putative causative mutation has been suggested in the promoter region of the SCD gene. Whole genome re-sequencing data was used for genotype imputation and to fine map the SSC14 QTL region in Norwegian Duroc. This effort confirms the location of the QTL on this chromosome as well as suggesting other putative candidate genes in the region. The most significant single nucleotide polymorphisms (SNPs) located on SSC14 explain between 55 and 76% of the genetic variance and between 27 and 54% of the phenotypic variance for the de novo synthesized fatty acid traits in Norwegian Duroc. For the QTL region on SSC8 in Landrace, the most significant SNP explained 19% of the genetic variance and 5% of the phenotypic variance for C16:1n-7.ConclusionsThis study confirms a major QTL affecting fatty acid composition on SSC14 in Duroc, which can be used in genetic selection to increase the level of fatty acid desaturation. The SSC14 QTL was not segregating in the Landrace population, but another QTL on SSC8 affecting C16:1n-7 was identified and might be used to increase the level of desaturation in meat products from this breed.

Feeding finishing heavy pigs with corn silages: effects on backfat fatty acid composition and ham weight losses during seasoning

The effect of diets containing corn silages (whole ear or high cut whole plant corn silages, WECS and HCCS, respectively) on fatty acid composition of back fat and the weight loss of thighs during the seasoning process were examined in Italian heavy pigs (from 90 to 160 kg of live weight). Two trials were conducted in the same farm, following an identical experimental protocol. In both trials, a control diet, based on dry corn, barley, wheat, extracted soybean meal, wheat bran and supplement (47, 23, 10, 9, 8 and 3% dry matter (DM), respectively) was compared with a diet containing 30% DM of WECS (trial 1) or 20% DM of HCCS (trial 2) in substitution of bran and part of the corn. The initial fresh weight of thighs was very homogeneous between the two trials and only at the end of seasoning the hams from pigs fed the corn silage diets were slightly lighter (of about 0.5 kg, p < .05). The dietary inclusion of corn silages determined a significant increase of the saturated fraction of the back fat (from 40.6 to 41.9%, p < .05), mainly due to the increase of the C 18:0 fatty acid (from 14.3 to 15.2%, p < .05). Overall, the calculated iodine value was favourable for the fat of pigs fed silages (62.63 vs. 64.24, p = .05). In conclusion, feeding corn silages to heavy pigs has limited impact on seasoning ham losses and can slightly improve backfat quality, in terms of fatty acid composition.

Effect of linseed and the combination of conjugated linoleic acid and linseed on the quality and oxidative stability of pig meat and subcutaneous fat

The aim of this experiment was to test the hypothesis that conjugated linoleic acid (CLA) in diets of finishing pigs fed linseed can improve the quality and oxidative stability of meat and subcutaneous fat. Twenty-four Prestice Black-Pied pigs (barrows and gilts) were divided into three groups and were fed a basal diet and diets supplemented with ground linseed (70 g/kg), or linseed combined with conjugated linoleic acid (20 g CLA-oil/kg). The trial duration was 53 days. Measurements included slaughter and meat quality parameters, oxidative stability determination, and fatty acid profile of meat and subcutaneous fat. The experimental data were analysed using one-way analysis of variance. Neither linseed nor linseed with CLA significantly influenced weight gain, lean percentage, muscle depth, backfat thickness, drip loss, meat shear force, dry matter, intramuscular fat or cholesterol (P &amp;gt; 0.05). Dietary supplementation with linseed increased the percentage of linolenic acid in the fatty acids of meat and backfat and resulted in higher production of aldehydes. Dietary CLA did not influence the susceptibility of lipids to oxidation. Supplementation with CLA significantly increased CLA proportions in fatty acids of meat and backfat, reduced proportions of monounsaturated fatty acids, and increased proportions of saturated fatty acids in backfat (P &amp;lt; 0.05). The concentration of CLA (in mg/100 g of fresh tissue) in backfat was almost fifty times higher than in meat. Both meat and backfat of pigs fed CLA-free diets contained CLA, probably as a result of microbial conversion of linoleic acid in the intestine. It can be concluded that CLA changed the fatty acid profile of meat and backfat, but did not improve oxidative stability and other meat quality traits of pigs fed linseed.

Re‐esterified oils from palm acid oil do not alter pork fatty acid composition

New fat products have been developed by chemically re‐esterifying acid oils (a by‐product of the food oil refining industry) with glycerol (a by‐product from biodiesel industry). These new products show lower free fatty acid content than acid oils and a fatty acid distribution within the positions of acylglycerols different from that of native oils. In this paper, we aim at assessing if the unique composition of re‐esterified palm oils (compared to native and acid oils) would affect pork and back fat fatty acid composition. A total of 24 pigs were fed one of the four experimental diets containing 4% experimental fat: native palm oil (PN), palm acid oil (PA), or two re‐esterified palm oils (PEL and PEH). Our results show that meat from pigs fed re‐esterified palm oils did not differ significantly in terms of total fatty acid and sn‐2 fatty acid compositions compared to PN or PA.Practical applications: Acid oils are by‐products of the food industry. They could be re‐utilized as feed ingredients but their free fatty acid content is usually high. High free fatty acid contents in diets have been related to low digestibility values when used in feed. New fat products have been developed by their chemical esterification with glycerol (a by‐product from biodiesel industry). Here, we have verified that these re‐esterified products would not alter pork fatty acid composition with respect to the use of native palm oil. Since results on productive parameters showed that they might increase feed efficiency and digestibility, overall the results support the re‐utilization of these fat by‐products in feed, alternative to the use of native palm oil or palm acid oil, provided that the benefits of the increase in feed efficiency counteract the cost of the esterification process.New fat products have been developed by chemically re‐esterifying palm acid oil (a by‐product of the palm oil refining industry) with glycerol. Compared to acid oils, they show a reduction of free fatty acids and an increase of partial acylglycerols. The fatty acid distribution within the positions of acylglycerols is different from that of native oils. This study has shown that their use in pig feed does not modify pork fatty acid composition compared to native or acid palm oil.

New insight into the SSC8 genetic determination of fatty acid composition in pigs.

BackgroundFat content and fatty acid composition in swine are becoming increasingly studied because of their effect on sensory and nutritional quality of meat. A QTL (quantitative trait locus) for fatty acid composition in backfat was previously detected on porcine chromosome 8 (SSC8) in an Iberian x Landrace F2 intercross. More recently, a genome-wide association study detected the same genomic region for muscle fatty acid composition in an Iberian x Landrace backcross population. ELOVL6, a strong positional candidate gene for this QTL, contains a polymorphism in its promoter region (ELOVL6:c.-533C < T), which is associated with percentage of palmitic and palmitoleic acids in muscle and adipose tissues. Here, a combination of single-marker association and the haplotype-based approach was used to analyze backfat fatty acid composition in 470 animals of an Iberian x Landrace F2 intercross genotyped with 144 SNPs (single nucleotide polymorphisms) distributed along SSC8.ResultsTwo trait-associated SNP regions were identified at 93 Mb and 119 Mb on SSC8. The strongest statistical signals of both regions were observed for palmitoleic acid (C16:1(n-7)) content and C18:0/C16:0 and C18:1(n-7)/C16:1(n-7) elongation ratios. MAML3 and SETD7 are positional candidate genes in the 93 Mb region and two novel microsatellites in MAML3 and nine SNPs in SETD7 were identified. No significant association for the MAML3 microsatellite genotypes was detected. The SETD7:c.700G > T SNP, although statistically significant, was not the strongest signal in this region. In addition, the expression of MAML3 and SETD7 in liver and adipose tissue varied among animals, but no association was detected with the polymorphisms in these genes. In the 119 Mb region, the ELOVL6:c.-533C > T polymorphism showed a strong association with percentage of palmitic and palmitoleic fatty acids and elongation ratios in backfat.ConclusionsOur results suggest that the polymorphisms studied in MAML3 and SETD7 are not the causal mutations for the QTL in the 93 Mb region. However, the results for ELOVL6 support the hypothesis that the ELOVL6:c.-533C > T polymorphism has a pleiotropic effect on backfat and intramuscular fatty acid composition and that it has a role in the determination of the QTL in the 119 Mb region.

Evolution of the fatty acid profile of subcutaneous back-fat adipose tissue in growing Iberian and Landrace × Large White pigs

The lipid content and fatty acid (FA) profile in pig tissues are strongly influenced by genotype and nutrient supply, with implications in meat quality. The de novo lipid synthesis and pattern of FA unsaturation could be an important cause of variation in the overall efficiency of energy utilization among breeds. To test the effects of pig genotype and CP supply on the evolution of back-fat tissue FA profile throughout the growing and finishing stages, 32 Iberian (IB) and Landrace × Large White (LR × LW) barrows were offered one of two diets differing in CP content (13% or 17% as fed). A pair-fed procedure (0.8 × ad libitum intake of IB pigs) was used. Subcutaneous fat samples were taken at the dorso-lumbar region at ∼38, 50, 65, 90 and 115 kg BW. Higher proportions of total monounsaturated FA (MUFA; P < 0.01) and lower proportions of total saturated FA (SFA; P < 0.01 to 0.05) were found in the outer back-fat layer of pigs both at 50 and 115 kg BW. Pig genotype affected the FA composition of both subcutaneous back-fat layers. The proportions of C18:0 and SFA in fat tissue were higher in IB than in LR × LW pigs from 38 to 65 kg BW, especially in the outer layer. In addition, MUFA contents were higher in IB pigs at 115 kg BW in both layers (+5% on average; P < 0.01). Increased proportions of C18:2 n-6 and polyunsaturated FA (PUFA) were found in LR × LW pigs, irrespective of the stage of growth and back-fat layer (P⩽0.02). At 50 kg BW, pigs receiving the high-protein diet presented the highest C18:2 n-6, C18:3 n-3, C20:5 n-3 and PUFA contents. A significant genotype × CP content interaction was observed for C18:3 n-3 because of the increased concentration of this FA in LR × LW pigs when offered the 17% CP diet (P < 0.05). Higher C16:0 and SFA contents (+5%; P = 0.03) were found in pigs offered the 13% CP diet and slaughtered at 115 kg BW. There was a genotype × CP interaction for MUFA concentration because of the higher MUFA content observed in IB pigs offered the highest protein content diet (P = 0.03). Our results suggest that genetic variation in de novo lipid synthesis and pattern of FA unsaturation might contribute to explain differences in back-fat FA profile of IB and LR × LW pigs under identical nutritional management. They could be also relevant to explain the low efficiency of nutrient and energy utilization in the IB pig.

Effects of increasing concentrations of glycerol in concentrate diets on nutrient digestibility, methane emissions, growth, fatty acid profiles, and carcass traits of lambs1

Two experiments were conducted to evaluate the effects of increasing concentrations of glycerol in concentrate diets on total tract digestibility, methane (CH4) emissions, growth, fatty acid profiles, and carcass traits of lambs. In both experiments, the control diet contained 57% barley grain, 14.5% wheat dried distillers grain with solubles (WDDGS), 13% sunflower hulls, 6.5% beet pulp, 6.3% alfalfa, and 3% mineral-vitamin mix. Increasing concentrations (7, 14, and 21% dietary DM) of glycerol in the dietary DM were replaced for barley grain. As glycerol was added, alfalfa meal and WDDGS were increased to maintain similar concentrations of CP and NDF among diets. In Exp.1, nutrient digestibility and CH4 emissions from 12 ram lambs were measured in a replicated 4 × 4 Latin square experiment. In Exp. 2, lamb performance was evaluated in 60 weaned lambs that were blocked by BW and randomly assigned to 1 of the 4 dietary treatments and fed to slaughter weight. In Exp. 1, nutrient digestibility and CH4 emissions were not altered (P = 0.15) by inclusion of glycerol in the diets. In Exp.2, increasing glycerol in the diet linearly decreased DMI (P < 0.01) and tended (P = 0.06) to reduce ADG, resulting in a linearly decreased final BW. Feed efficiency was not affected by glycerol inclusion in the diets. Carcass traits and total SFA or total MUFA proportions of subcutaneous fat were not affected (P = 0.77) by inclusion of glycerol, but PUFA were linearly decreased (P < 0.01). Proportions of 16:0, 10t-18:1, linoleic acid (18:2 n-6) and the n-6/n-3 ratio were linearly reduced (P < 0.01) and those of 18:0 (stearic acid), 9c-18:1 (oleic acid), linearly increased (P < 0.01) by glycerol. When included up to 21% of diet DM, glycerol did not affect nutrient digestibility or CH4 emissions of lambs fed barley based finishing diets. Glycerol may improve backfat fatty acid profiles by increasing 18:0 and 9c-18:1 and reducing 10t-18:1 and the n-6/n-3 ratio.

Backfat Fatty Acid Profile of Crossbred Pigs Fed a Diet Supplemented with Conjugated Linoleic acid or Sunflower Oil

Backfat Fatty Acid Profile of Crossbred Pigs Fed a Diet Supplemented with Conjugated Linoleic acid or Sunflower OilThe aim of the study was to investigate the impact of feeding pigs with different levels of conjugated linoleic acid (CLA) or sunflower oil (SFO) on the backfat fatty acid profile. The subjects of research were 60 crossbred gilts divided into 6 groups, which were fed different levels of conjugated linoleic acid or sunflower oil (0.5, 1.0 and 2.0%, respectively). All fatteners were kept and fed under standardized conditions. Animals were slaughtered at 95 kg of body weight. Fatty acid profile was determined in samples of backfat from each animal using gas chromatography. The significance of differences between groups was verified by Duncan's test. In the present study, a beneficial effect of adding CLA was that it reduced saturated fatty acids and increased unsaturated fatty acids in the adipose tissue (backfat) of pigs as compared to fatteners receiving SFO. The amount of monounsaturated fatty acids in the backfat decreased with increasing amounts of CLA or SFO. Modifying the fatty acid profile of pig backfat through addition of CLA or SFO would be beneficial to the health of consumers because relatively large amounts of fat pork, including backfat, are added to the sausages.