Interactions between genotype, dietary fat saturation and vitamin A concentration on intramuscular fat content and fatty acid composition in pigs

Sustainable pig diets: partial grain replacement with former food products and its impact on meat quality

This study investigated the effects of salty and sugary former foodstuff products (FFPs) on the quality traits and meat composition of 36 male castrated pigs (Swiss Large White breed) as well as sensory characteristics of the loins. The animals were fed three different diets for both the growing (G) and finishing (F) phases: (1) a standard diet (ST), 0% FFPs; (2) a diet with 30% of sugary FFPs (e.g., chocolate, biscuits, cakes) as a replacement for traditional ingredients (SU); and (3) a diet with 30% of salty FFPs (e.g., bread, pasta, and breadsticks) as a replacement for traditional ingredients (SA). For a comprehensive assessment of meat quality, protein and fat content in the LD were analyzed. AA and FA profile were determined both in the LD and backfat. Meat quality traits such as pH and temperature, thawing, cooking and drip losses, and shear force have been evaluated. Then, pork loins have been assessed for sensory attributes by a trained sensory panel. The SA diet decreased 20:5 n-3 levels (P < 0.001) in the muscle and 22:5 n-3 levels (P < 0.05) in both muscle and backfat but increased (P < 0.05) the ratio of mono-unsaturated to saturated fatty acids compared to the ST group. Both the SU and SA diets elevated (P < 0.001) the n-6:n-3 fatty acids ratio compared to the ST diet. Dietary treatments did not affect other meat quality traits. Regarding sensory attributes, the loin from pigs fed with SU and SA diets were sweeter (P < 0.001). Loins of SA pigs were more tender (P < 0.001), had a more intense pork aroma (P < 0.001) and had more flavor (P < 0.01) compared to ST loins. Overall, the use of FFPs affected the fatty acid profile of pork while improving the sensory quality of the loins, with no negative effects observed on the technological and nutritional quality of the meat.

Instrumental and Sensory Analyses of Salami from Autochthonous and Conventional Pig Breeds

Typical salami produced from Mora Romagnola (MR), an autochthonous pig breed extensively farmed within a geographically confined Italian area, are food products of commercial interest. This investigation aimed to highlight elements for the recognition and authentication of such typical salami. Five MR salami were analyzed using a sensory and instrumental approach, and the results were compared with those from eight salami made from a conventional pig breed. The sensory profiles were defined through attributes such as seasoning, pepper, garlic, fermented etc.; no differences in the products ascribable to the pig breed were highlighted. By analyzing volatile compounds, 33 molecules were detected; significant differences were found among samples, probably related to processing methods. Color differences between MR and conventional salami were identified by an electronic eye. According to instrumental texture analysis, large variability among the MR samples was detected, probably related to different types of salami (recipe, casing, size, ripening). Correlations were found among the sensory results, volatile compounds, and textural properties of the samples. Most differences do not appear to be specifically related to MR breed; only red color intensity evaluated by an electronic eye showed a correlation with breed, i.e., MR salami. This study highlights the large variability among the salami analyzed.

Genes Related to Fat Metabolism in Pigs and Intramuscular Fat Content of Pork: A Focus on Nutrigenetics and Nutrigenomics

Simple Summary

The intramuscular fat (IMF) or marbling is an essential pork sensory quality that influences the preference of the consumers and premiums for pork. IMF is the streak of visible fat intermixed with the lean within a muscle fibre and determines sensorial qualities of pork such as flavour, tenderness and juiciness. Fat metabolism and IMF development are controlled by dietary nutrients, genes, and their metabolic pathways in the pig. Nutrigenetics explains how the genetic make-up of an individual pig influences the pig’s response to dietary nutrient intake. Differently, nutrigenomics is the analysis of how the entire genome of an individual pig is affected by dietary nutrient intake. The knowledge of nutrigenetics and nutrigenomics, when harmonized, is a powerful tool in estimating nutrient requirements for swine and programming dietary nutrient supply according to an individual pig’s genetic make-up. The current paper aimed to highlight the roles of nutrigenetics and nutrigenomics in elucidating the underlying mechanisms of fat metabolism and IMF deposition in pigs. This knowledge is essential in redefining nutritional intervention for swine production and the improvement of some economically important traits such as growth performance, backfat thickness, IMF accretion, disease resistance etc., in animals.

Abstract

Fat metabolism and intramuscular fat (IMF) are qualitative traits in pigs whose development are influenced by several genes and metabolic pathways. Nutrigenetics and nutrigenomics offer prospects in estimating nutrients required by a pig. Application of these emerging fields in nutritional science provides an opportunity for matching nutrients based on the genetic make-up of the pig for trait improvements. Today, integration of high throughput “omics” technologies into nutritional genomic research has revealed many quantitative trait loci (QTLs) and single nucleotide polymorphisms (SNPs) for the mutation(s) of key genes directly or indirectly involved in fat metabolism and IMF deposition in pigs. Nutrient–gene interaction and the underlying molecular mechanisms involved in fatty acid synthesis and marbling in pigs is difficult to unravel. While existing knowledge on QTLs and SNPs of genes related to fat metabolism and IMF development is yet to be harmonized, the scientific explanations behind the nature of the existing correlation between the nutrients, the genes and the environment remain unclear, being inconclusive or lacking precision. This paper aimed to: (1) discuss nutrigenetics, nutrigenomics and epigenetic mechanisms controlling fat metabolism and IMF accretion in pigs; (2) highlight the potentials of these concepts in pig nutritional programming and research.

Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs

BACKGROUND

The composition of intramuscular fat depends on genetic and environmental factors, including the diet. In pigs, we identified a haplotype of three SNP mutations in the stearoyl-coA desaturase (SCD) gene promoter associated with higher content of monounsaturated fatty acids in intramuscular fat. The second of these three SNPs (rs80912566, C > T) affected a putative retinol response element in the SCD promoter. The effect of dietary vitamin A restriction over intramuscular fat content is controversial as it depends on the pig genetic line and the duration of the restriction. This study aims to investigate changes in the muscle transcriptome in SCD rs80912566 TT and CC pigs fed with and without a vitamin A supplement during the fattening period.

RESULTS

Vitamin A did not affect carcass traits or intramuscular fat content and fatty acid composition, but we observed an interaction between vitamin A and SCD genotype on the desaturation of fatty acids in muscle. As reported before, the SCD-TT pigs had more monounsaturated fat than the SCD-CC animals. The diet lacking the vitamin A supplement enlarged fatty acid compositional differences between SCD genotypes, partly because vitamin A had a bigger effect on fatty acid desaturation in SCD-CC pigs (positive) than in SCD-TT and SCD-TC animals (negative). The interaction between diet and genotype was also evident at the transcriptome level; the highest number of differentially expressed genes were detected between SCD-TT pigs fed with the two diets. The genes modulated by the diet with the vitamin A supplement belonged to metabolic and signalling pathways related to immunity and inflammation, transport through membrane-bounded vesicles, fat metabolism and transport, reflecting the impact of retinol on a wide range of metabolic processes.

CONCLUSIONS

Restricting dietary vitamin A during the fattening period did not improve intramuscular fat content despite relevant changes in muscle gene expression, both in coding and non-coding genes. Vitamin A activated general pathways of retinol response in a SCD genotype-dependant manner, which affected the monounsaturated fatty acid content, particularly in SCD-CC pigs.

Short-Term Spirulina (Spirulina platensis) Supplementation and Laying Hen Strain Effects on Eggs' Lipid Profile and Stability

Simple Summary

Spirulina is an alga rich in micronutrients of interest for improving the nutritional value and quality of the products. This study evaluates the transfer of some of these micronutrients (vitamins and fatty acids) in egg yolk when short periods of supplementation are used in hens of two different strains, and its consequent effects on some quality parameters. Short-term spirulina supplementation markedly modified vitamin content and color in yolk. Hen strain mainly affected the fatty acid profile, and a different response to retinol content and fatty acid proportions (mainly monounsaturated and desaturase activity) according to spirulina supplementation and breed of hens was observed.

Abstract

The aim of the study was to investigate the effect of short-term dietary spirulina supplementation (1% and 3%) and the strain of laying hens (White Leghorn: WL and Rhode Island Red: RIR) on color, nutritional value, and stability of yolk. Egg weight was not affected by any of the studied effects. Yolks from 3%-spirulina supplemented hens had higher retinol and lower α-tocopherol content (p = 0.0001) when compared to control. The supplementation with 1%-spirulina markedly decreased luminosity and increased redness (p = 0.0001) and yellowness (p = 0.0103). Short-term spirulina supplementation slightly modified the fatty acid composition of yolk. The C16-desaturase index increased with the algae, whereas other egg quality indices (hypocholesterolemic, thrombombogenic, n-6/n-3) were not modified. Hen strain mainly affected to the lipid profile. The RIR hens accumulated greater yolk retinol with supplementation doses of 3% (p < 0.05), while the WL hardly suffered changes in the accumulation. Also, yolks from RIR hens had lower C16:0 (p = 0.0001), C18:0 (p = 0.0001), saturated (SAT) (p = 0.0001), and thrombogenic index (p = 0.0001), C20:3n-6 (p = 0.0001), n-6/n-3 ratio (p = 0.003), Δ-6+5-desaturase (p = 0.0005), total elongase indices (p = 0.0001) when compared to WL. Moreover, RIR had higher monounsaturated (MUFA), Δ-9-desaturase and hypocholesterolemic indices (p < 0.05) than WL. A different response to spirulina supplementation was observed for C18:1n-9, MUFA, Δ-9-desaturase and thiesterase indices (p < 0.05) according to hen strain. Yolks from RIR had higher MUFA and Δ-9-desaturase indices than WL at 1%-spirulina supplementation, whereas these parameters were less affected in RIR supplemented with 3%. SAT and Δ-9-desaturase were significantly correlated (r = −0.38 and 0.47, respectively) with retinol content according to a linear adjustment (p < 0.05). Lipid oxidation of yolk was slightly modified by the dietary treatment or hen strain. It was detected a relationship between TBARS and α-tocopherol, C22:5n-3 or C22:6n-3 (p < 0.05). L* and a* were also inversely or positively related with yolk retinol content according to a linear response (p < 0.05). The administration of 1% of spirulina in diets of red hens would be an interesting alternative to get healthier eggs from the nutritional point of view, obtaining an adequate color and without modifications in other yolk quality traits.

Comparison of Growth Performance and Meat Quality Traits of Commercial Cross-Bred Pigs versus the Large Black Pig Breed

The meat quality of different pig breeds is associated with their different muscle tissue physiological processes, which involves a large variety of genes related with muscle fat and energy metabolism. Understanding the differences of biological processes of muscle after slaughter is helpful to reveal the meat quality development of different breeds. Therefore, eight native Large Black pigs (BP), with high fat content in meat, and seven cross-bred commercial pigs (CP), which had a high feed efficiency with high lean meat, were used to investigate the differences in their meat quality and RNA transcriptomes. The average daily gain (ADG) and hot carcass weight (HCW) of CP were higher than BP, but the back-fat thickness of BP was higher than CP (p < 0.05). The CP had higher a* (redness) but lower h (hue angle) than BP (p < 0.05). The metmyoglobin (MMb) percentage of CP was higher (p < 0.05) than BP. The fat content and oxygen consumption of longissimus dorsi (LD) muscles in BP were higher (p < 0.05) than CP. BP had higher monounsaturated fatty acids (MUFA) content, but CP had higher polyunsaturated fatty acids (PUFA) content (p < 0.05). The RNA-seq data highlighted 201 genes differentially expressed between the two groups (corrected false discovery rate (FDR) p < 0.05), with 75 up-regulated and 126 down-regulated genes in BP compared with CP using the fold change (FC). The real-time PCR was used to validate the results of RNA-seq for eight genes, and the genes related to lipid and energy metabolism were highly expressed in BP (p < 0.05). Based on the results, BP had superior intramuscular fat content to CP, while the growth performance of CP was better, and the transcriptomic differences between these two groups of pigs may cause the meat quality and growth performance variance.

Effects of Effective Microorganisms on Meat Quality, Microstructure of the Longissimus Lumborum Muscle, and Electrophoretic Protein Separation in Pigs Fed on Different Diets

Simple Summary

Pork is the most popular meat among consumers in Poland, but it can also be a source of pathogens. Therefore, there is a need to find effective prophylaxis in order to ensure that consumers have access to safe food with the desired nutritional qualities and, above all, food that is free of pathogens. In order to meet these expectations, producers use probiotics containing effective microorganisms (EMs) offered in the market. In this study the same probiotic, EM Bokashi, was used for the first time in combination with three nutritional variants with proteins of different origin.

Abstract

The aim of the study was to determine how effective microorganisms influence meat quality, the microstructure of the longissimus lumborum muscle, and electrophoretic protein separation. The study group consisted of 150 piglets divided into three feeding groups: C, E1, and E2. The feeding groups included C—a standard fodder blend with a full share of post-extracted soya meal; E1—a 50%/50% mix of pea and lupine/soya bean in phase I of fattening and a 75%/25% mix of pea and lupine/soya bean in phase II of fattening; and E2—a 50%/50% mix of pea and lupine/soya bean in phase I of fattening and in 100% pea and lupine in phase II of fattening. The experimental factor was the addition of the EM Carbon Bokashi probiotic to the diet (C + EM, E1 + EM, E2 + EM). Influence of the feeding system on the following parameters was also estimated. After slaughter, the meat quality, LL muscle microstructure, and electrophoretic protein separation were assessed. In the C + EM group, a lower water-holding capacity was demonstrated. Meat from pigs fed the effective microorganism additive was much harder in the E1+EM group compared to meat from pigs from the E1 group. A beneficial effect of effective microorganism was found in the E2 + EM group, where less thermal leakage from the meat was demonstrated. A beneficial effect of the feeding system on thermal leakage and loin eye area in the E2 + EM group was demonstrated. In the C + EM group, a lower total number of muscle fibers was demonstrated. The addition of effective microorganism caused an increase in the diameter of fast twitch fibers in the E1 + EM group. In the same group of pigs, effective microorganisms caused a lower proportion of fiber fission. This nutritional variant appears to be the most appropriate for proteins as well, because it led to the most favorable percentage of individual proteins after effective microorganisms supplementation in the longissimus lumborum muscle.

Effects of dietary fat saturation level on growth performance, carcass traits, blood lipid parameters, tissue fatty acid composition and meat quality of finishing pigs

Objective

The objective of this study was to investigate the effects of various dietary unsaturated to saturated fatty acids ratios (UFA to SFA ratios) on growth performance, carcass traits, blood lipid parameters, tissue fatty acid (FA) composition, and meat quality of finishing pigs.

Methods

A total of 45 crossbred pigs ([Duroc×Landrace]×Yorkshire), with an average initial body weight of 60.3±2.4 kg, were randomly allocated to three treatment groups of 1:1, 2:1, and 3:1 dietary UFA to SFA ratios.

Results

Both average daily gain and average daily feed intake of pigs were decreased linearly (p<0.05), whereas backfat thickness was decreased linearly (p<0.05) with increasing of dietary UFA to SFA ratio. Serum triglyceride and low density lipoprotein cholesterol were decreased quadratically or linearly (p<0.05) respectively, whereas high density lipoprotein cholesterol was increased quadratically (p<0.05) with increasing dietary UFA to SFA ratio. In M. longissimus thoracis, the proportion of C18:1 and monounsaturated FA was decreased linearly (p<0.05), whereas the proportion of C18:2n-6, C20:4n-6 and polyunsaturated FA (PUFA) were increased linearly (p<0.05) as dietary UFA to SFA ratio increased. In the subcutaneous adipose tissue, the proportion of SFA was decreased linearly (p<0.05), whereas the proportion of n-6 PUFA, n-3 PUFA, and the UFA to SFA ratios were increased linearly (p<0.05) with increasing of dietary UFA to SFA ratio. Meat color scores and shear force of pigs were decreased linearly (p<0.05), whereas drip loss and cooking loss were increased linearly (p<0.05) with increasing of dietary UFA to SFA ratio.

Conclusion

Appropriately boosted dietary UFA to SFA ratio could be conductive to optimize blood lipid parameters and tissue FA composition. However, when the ratio is too high or too low it tends to have negative effects on growth performance and meat quality.

A diet based on cured acorn-fed ham with oleic acid content promotes anti-inflammatory gut microbiota and prevents ulcerative colitis in an animal model

Background

Diets based on meat products are not recommended in the case of ulcerative colitis (UC). The objective here is to test if some traditional cured meat products, as acorn-fed ham (high levels of oleic acid), may be useful for controlling inflammatory diseases as UC in animal models, which could represent a new dietary complementary intervention in the prevention of this inflammatory disease in humans.

Methods

Two rat cohorts have been used: conventional vegetable rat feed and acorn-fed ham. UC was induced with DSS in drinking water ad libitum for 1 week. Short-chain fatty acids (SCFAs) and 16S rRNA metagenomics from bacterial populations were analyzed in cecum samples. Colon samples were analyzed for histological parameters.

Results

Acorn-fed ham diet induced changes in gut microbiota composition, with pronounced enrichments in anti-inflammatory bacterial genera (Alistipes, Blautia, Dorea, Parabacteroides). The animals with this diet showed a strong reduction in most parameters associated to ulcerative colitis: disease activity index, macroscopic score of colitis, epitelium alteration in colon mucosa, inflammatory cell density in colon, myeloperoxidase titers in colon, proinflammatory cytokines (IL-17, IFN-γ). Also, acorn-fed ham diet animals showed increased total antioxidant activity an oleic acid levels in plasma, as well as higher short-chain fatty acid concentrations in cecum (isobutyric, isovaleric and valeric).

Conclusions

In the acorn-fed ham cohort, as a result of the dietary intake of oleic acid and low intake of omega-6 fatty acids, a strong preventive effect against UC symptoms was observed.

Composition and functional diversity of fecal bacterial community of wild boar, commercial pig and domestic native pig as revealed by 16S rRNA gene sequencing

The bacterial community in mammalian gastrointestinal tract is abundant and complex. To date, little is known about the gut microbiota of wild boar. This study aimed to investigate the fecal bacterial diversity of wild boar and compare with commercial pig and domestic native pig. The diet composition showed that the diets of wild boar, commercial pig and domestic native pig were different from each other. More than 1,760,000 quality-filtered sequences were obtained, and the results revealed distinct compositions and diversity of fecal microbiota in three groups. PCoA and NMDS analyses showed that fecal bacterial communities of wild boar, commercial pig and domestic native pig formed distinctly different clusters. Although the three groups shared a large size of OTUs comprising a core microbiota community, a strong distinction existed at family and genus levels. Ruminococcaceae, Prevotellaceae and Christensenellaceae were more abundant in the feces of wild boar than in domestic native pig and commercial pig. At the genus level, the proportion of unidentified Christensenellaceae was remarkably higher in wild boar group, while commercial pig and domestic native pig group had a higher abundance of Streptococcus and Lactobacillus. Tax4Fun predictions of metagenome function showed statistically significant differences in the functions of fecal microbiota in three groups. There were more bacteria genes with amino acid metabolism, cell growth and death, cell motility, energy metabolism, immune system and environmental adaptation observed in wild boar feces, while commercial pig feces contained more bacteria genes with carbohydrate metabolism, drug resistance, aging, infectious diseases, lipid metabolism, endocrine and metabolic diseases. These results indicated that the fecal microbial ecosystem of the wild boar is significantly different from that of domestic native pig and commercial pig, suggesting that diet is an important factor leading to differences in bacterial abundance and diversity in feces.

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.

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Genetics and breeding for intramuscular fat and oleic acid content in pigs

The intramuscular fat (IMF) and oleic acid (OL) content have been favorably related to pork quality and human health. This influences the purchasing behavior of consumers and, therefore, also shifts the attention of breeding companies toward whether these traits are included into the breeding goal of the lines producing for high-valued markets. Because IMF and OL are unfavorably associated with lean content, a key economic trait, the real challenge for the industry is not simply to increase IMF and OL, but rather to come up with the right trade-off between them and lean content. In this paper we review the efforts performed to genetically improve IMF and OL, with particular reference to the research we conducted in a Duroc line aimed at producing high quality fresh and dry-cured pork products. Based on this research, we conclude that there are selection strategies that lead to response scenarios where IMF, OL, and lean content can be simultaneously improved. Such scenarios involve regular recording of IMF and OL, so that developing a cost-efficient phenotyping system for these traits is paramount. With the economic benefits of genomic selection needing further assessment in pigs, selection on a combination of pedigree-connected phenotypes and genotypes from a panel of selected genetic markers is presented as a suitable alternative. Evidence is provided supporting that at least a polymorphism in the leptin receptor and another in the stearoyl-CoA desaturase genes should be in that panel. Selection for IMF and OL results in an opportunity cost on lean growth. The extent to which it is affordable relies on the consumers' willingness to pay for premium products and on the cost to benefit ratio of alternative management strategies, such as specific dietary manipulations. How the genotype can influence the effect of the diet on IMF and OL remains a topic for further research.

Carotenoid intake and SCD genotype exert complementary effects over fat content and fatty acid composition in Duroc pigs

Nutritional and genetic strategies are needed to enhance intramuscular fat (IMF) and MUFA content without altering carcass leanness. Dietary vitamin A restriction has been suggested to specifically promote IMF, whereas a polymorphism of the () gene has shown to specifically increase MUFA. The purpose of this study was to investigate the combined effects of provitamin A (PVA) carotenoid intake and genotype (>) on hepatic retinoid content and on the liver, muscle (LM and gluteus medius [GM]), and subcutaneous fat (SF) content and fatty acid composition. Following a split-plot design, 32 castrated Duroc pigs, half of each of the 2 homozygous genotypes (CC and TT), were subjected from 165 to 195 d of age to 2 finishing diets differing in the PVA carotenoid content (an enriched-carotene diet [C+] and a control diet [C-]). Both diets were identical except for the corn line used in the feed. The C+ was formulated with 20% of a carotenoid-fortified corn (M37W-Ph3) whereas the C- instead used 20% of its near isogenic M37W line, which did not contain PVA carotenoids. No vitamin A was added to the diets. The C- was estimated to provide, at most, 1,300 IU of vitamin A/kg and the C+ to supply an extra amount of at least 800 IU vitamin A/kg. Compared with the pigs fed the C-, pigs fed with C+ had 3-fold more retinoic acid ( < 0.01) and 4-fold more gene expression in the liver ( = 0.06). The diet did not affect performance traits and backfat thickness, but pigs fed the C+ had less fat (4.0 vs. 5.0%; = 0.07) and MUFA (18.3 vs. 22.5%; = 0.01) in the liver, less IMF (5.4 vs. 8.3%; = 0.04) in the GM, and more fat content (90.4 vs. 87.9%; = 0.09) and MUFA (48.0 vs. 46.6%; = 0.04) in SF. The TT genotype at the gene increased MUFA ( < 0.05) in all tissues (21.4 vs. 19.5% in the liver, 55.0 vs. 53.1% in the LM, 53.9 vs. 51.7% in the GM, and 48.0 vs. 46.7% in SF for TT and CC genotypes, respectively). Liver fat and MUFA content nonlinearly declined with liver all- retinoic acid, indicating a saturation point at relatively low all- retinoic acid content. The results obtained provide evidence for a complementary role between dietary PVA and genotype, in the sense that the TT pigs fed with a low-PVA diet are expected to show higher and more monounsaturated IMF without increasing total fat content.

Recent advances in rapid and nondestructive determination of fat content and fatty acids composition of muscle foods

Conventional methods for determining fat content and fatty acids (FAs) composition are generally based on the solvent extraction and gas chromatography techniques, respectively, which are time consuming, laborious, destructive to samples and require use of hazard solvents. These disadvantages make them impossible for large-scale detection or being applied to the production line of meat factories. In this context, the great necessity of developing rapid and nondestructive techniques for fat and FAs analyses has been highlighted. Measurement techniques based on near-infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance and hyperspectral imaging have provided interesting and promising results for fat and FAs prediction in varieties of foods. Thus, the goal of this article is to give an overview of the current research progress in application of the four important techniques for fat and FAs analyses of muscle foods, which consist of pork, beef, lamb, chicken meat, fish and fish oil. The measurement techniques are described in terms of their working principles, features, and application advantages. Research advances for these techniques for specific food are summarized in detail and the factors influencing their modeling results are discussed. Perspectives on the current situation, future trends and challenges associated with the measurement techniques are also discussed.

Effects of the ratio of unsaturated fatty acid to saturated fatty acid on the growth performance, carcass and meat quality of finishing pigs

The effects on finishing pigs (80–100 kg BW) fed diets supplemented with oil sources containing different ratios of unsaturated to saturated fatty acids (UFA:SFA ratio) were evaluated in 15 barrows and 15 gilts (Duroc × Large White × Landrace). Three experimental diets were evaluated using a randomized complete block design, with broken rice, soybean meal and rice bran as the main feedstuffs in the control diet. Diets 2 and 3 consisted of the control diet supplemented with 3% oil, with UFA:SFA ratios of 2.5:1 and 5:1, respectively. Overall, there was no significant difference (P > 0.05) found in the average daily gain (ADG) of the pigs fed the treatment diets; however, the pigs fed the control diet and diet 3 had better (P < 0.05) feed conversion ratios (FCR) than the pigs fed diet 2. The pigs fed diets 2 and 3, which were supplemented with oil at UFA:SFA ratios of 2.5:1 and 5:1, had greater (P < 0.05) average daily feed intakes (ADFI) than the pigs in the control group. Additionally, it was found that the gender of the pigs had an effect (P < 0.05) on the FCR. Interaction effects between the experimental diets and the gender of the pigs (P < 0.05) were found in the ADFI and FCR. There were no significance differences (P > 0.05) among the treatment groups with regard to the carcass quality of the pigs; however, it was found that the gilts had greater (P < 0.01) loin eye areas than the barrows fed diets 2 and 3 and the loin eye area of pig fed diet 2 was the largest (P < 0.05). In the case of the meat quality parameters, it was clearly found that the pigs fed the control diet had a greater (P < 0.05) lightness (L^∗) in the meat colour, and the lowest cooking loss was found in the pigs fed the diet supplemented with fat containing the UFA:SFA ratio of 5:1. Overall, the dietary treatment did not significantly affect the drip loss, thawing loss and shear force of the pork. In conclusion, the supplementation of oil with UFA:SFA ratios of 2.5:1 and 5:1 has the potential to improve pork quality.

Vitamin A and arachidonic acid altered the skeletal mineralization in Atlantic cod (Gadus morhua) larvae without any interactions on the transcriptional level

The main object of this study was to evaluate the impact of different levels of vitamin A (VA) and arachidonic acid (ARA) in relation to eicosapentaenoic acid (EPA) on mineralization and gene expression in Atlantic cod larvae (Gadus morhua). First-feeding larvae were fed enriched rotifers from start-feeding until 29 days post hatch (dph). Larvae in four tanks were fed one of the following diets: control (EPA/ARA ratio: 15.8, 0.9μg VA g(-1)), control+VA (EPA/ARA ratio: 15.8, 7.8μg VA g(-1)), High ARA (EPA/ARA ratio: 0.9, 1.5μg VA g(-1)) or High ARA+VA (EPA/ARA ratio: 0.9, 12.0μg VA g(-1)). Larvae fed High ARA+VA were shorter at 29dph compared to the other groups and had significantly less mineralized bones when comparing larvae of similar size, showing interaction effects between VA and ARA. Although transcriptomic analysis did not reveal any interaction effects, a higher number of genes were differentially expressed in the high ARA fed larvae compared to control+VA fed larvae. Furthermore, bglap1, bglap2 and col10a1 were all down-regulated in larvae fed High ARA-diets and to a greater extent than larvae fed VA supplemented diet, indicating an additive effect on mineralization. In conclusion, this study showed that the dietary increase in ARA and VA altered the skeletal metabolism during larval development, most likely through signaling pathways specific for each nutrient rather than an interaction. The present study also demonstrates that VA could affect the larval response to ARA, even within the accepted non-toxic/non-deficient range.

Review: Pork belly quality, bacon properties and recent consumer trends

Soladoye, P. O., Shand, P. J., Aalhus, J. L., Gariépy, C. and Juárez, M. 2015. Review: Pork belly quality, bacon properties and recent consumer trends. Can. J. Anim. Sci. 95: 325–340. Several factors can affect pork belly quality and, subsequently, bacon quality. Going by the recent trends in the bacon market and bearing in mind the more choosy nature of the consuming populace, it is imperative to consider the factors that can affect or improve bacon quality, thereby sustaining the current market surge. In as much as both genetic and environmental factors have been identified as largely affecting muscle food quality, nutritional interventions also seem to be a very viable tool to improve the quality of meat and its products. Processing and storage methods can also affect bacon quality, including microbial quality, physicochemical attributes and palatability. Both objective and subjective measures have been explored in assessing belly quality, most of which use belly softness and fatty acid profile as yardsticks, whereas bacon quality has been widely assessed only subjectively in terms of fat quality and slice integrity. Although consumers’ and producers’ quality perceptions seem to be in conflict, it is the responsibility of all stakeholders in the bacon industries to come together in ensuring a balanced approach to satisfy both parties along the production chain.

Dietary vitamin A restriction affects adipocyte differentiation and fatty acid composition of intramuscular fat in Iberian pigs

The aim of this study was to investigate whether dietary vitamin A level is associated with differences in adipocyte differentiation or lipid accumulation in Iberian pigs at early growing (35.8kg live weight) and at finishing (158kg live weight). Iberian pigs of 16.3kg live weight were allocated to two feeding groups, one group received 10,000IU of vitamin A/kg diet (control); the other group received a diet with 0IU of vitamin A (var) for the whole experimental period. The dietary vitamin A level had no effect on growth performance and carcass traits. The early suppression of vitamin A increased the preadipocyte number in Longissimus thoracis (LT) muscle in the early growth period (P<0.001) and the neutral lipid content and composition (higher MUFA and lower SFA content) at the end of the finishing period (P<0.05). Vitamin A restriction in young pigs increases their lipogenic potential without affecting carcass traits.

Effect of micellized natural (D-α-tocopherol) vs. synthetic (DL-α-tocopheryl acetate) vitamin E supplementation given to turkeys on oxidative status and breast meat quality characteristics

This study evaluates the effect of vitamin E supplementation source (micellized natural vs. the synthetic form) and dosage (40, 80, or 120 mg/kg) on α-tocopherol concentration in plasma and muscle, antioxidant capacity, and breast meat quality in turkeys. Three hundred female turkeys were randomly selected at an average live weight 63.2 g±0.5 and distributed into 7 groups. One group (control) was fed a standard diet without vitamin E supplementation and the other 6 were given mixed diets supplemented with the natural (d-α-tocopherol) or synthetic (dl-α-tocopheryl acetate) form of vitamin E in 3 dosages (40, 80, or 120 mg/kg). Following 11 wk feeding, results showed that performance parameters were not modified either by source or dosage of vitamin E supplementation to the turkeys. Plasma and muscle α-tocopherol at d 9 of refrigerated storage were higher when turkeys were supplemented with the natural form at higher doses. Losses in the concentration of α-tocopherol in meat between the beginning and the end of the 9 d refrigerated storage were greater in the groups supplemented with the synthetic form of vitamin E compared to those receiving the natural supplementation. The relationship between plasma α-tocopherol and the Trolox equivalent antioxidant capacity followed a different trend depending on the vitamin E source. Intramuscular fat was not significantly affected by the vitamin E source supplementation; however the slope of the linear regression equation was lower for the natural form than for the synthetic form. Turkeys given the natural form had higher C18:1n-9 but lower C15:1, C17:1, C20:5n-3, and C22:6n-3 in breast muscle. Meat samples from turkeys supplemented with natural vitamin E had higher deoxymyoglobin at d 3, 6, and 9 and lower metmyoglobin at d 9 of refrigerated storage than those receiving the synthetic form. Dietary supplementation with medium doses (80 mg/kg) micellized d-α-tocopherol is an interesting feeding strategy for ensuring antioxidant status and improving meat quality.

Alternative method for intramuscular fat analysis using common laboratory equipment

A procedure to quantify intramuscular fat was developed using common inexpensive laboratory equipment. Three homogenization methods of lyophilized muscle samples (Ball-mill, Grinder and Mortar) and two extraction methods (Ball-mill or Vortex) were used in turkey meat and pork. Two-hundred mg of lyophilized and homogenized samples were accurately weighed and mixed with 1.5 mL of dichloromethane-methanol (8:2) and shaken either in a Mixer Mill (MM400, Retsch Technology) or in a Vortex. The final mixture was separated by centrifugation. Solvent was evaporated under a nitrogen stream and lipid content was gravimetrically determined. Besides, it was checked that the fatty acid profile was not altered by the protocol used. Moreover, the analysis of 4 replicas from the same sample showed different variation coefficients (16-29%) for the new procedures proposed over a wide range of IMF content. The combination of Grinder and Vortex methodologies can be proposed as a simple and inexpensive alternative to previous ones.

A functional variant in the stearoyl-CoA desaturase gene promoter enhances fatty acid desaturation in pork

There is growing public concern about reducing saturated fat intake. Stearoyl-CoA desaturase (SCD) is the lipogenic enzyme responsible for the biosynthesis of oleic acid (18 ∶ 1) by desaturating stearic acid (18 ∶ 0). Here we describe a total of 18 mutations in the promoter and 3' non-coding region of the pig SCD gene and provide evidence that allele T at AY487830:g.2228T>C in the promoter region enhances fat desaturation (the ratio 18 ∶ 1/18 ∶ 0 in muscle increases from 3.78 to 4.43 in opposite homozygotes) without affecting fat content (18 ∶ 0+18 ∶ 1, intramuscular fat content, and backfat thickness). No mutations that could affect the functionality of the protein were found in the coding region. First, we proved in a purebred Duroc line that the C-T-A haplotype of the 3 single nucleotide polymorphisms (SNPs) (g.2108C>T; g.2228T>C; g.2281A>G) of the promoter region was additively associated to enhanced 18 ∶ 1/18 ∶ 0 both in muscle and subcutaneous fat, but not in liver. We show that this association was consistent over a 10-year period of overlapping generations and, in line with these results, that the C-T-A haplotype displayed greater SCD mRNA expression in muscle. The effect of this haplotype was validated both internally, by comparing opposite homozygote siblings, and externally, by using experimental Duroc-based crossbreds. Second, the g.2281A>G and the g.2108C>T SNPs were excluded as causative mutations using new and previously published data, restricting the causality to g.2228T>C SNP, the last source of genetic variation within the haplotype. This mutation is positioned in the core sequence of several putative transcription factor binding sites, so that there are several plausible mechanisms by which allele T enhances 18 ∶ 1/18 ∶ 0 and, consequently, the proportion of monounsaturated to saturated fat.

A laboratory efficient method for intramuscular fat analysis

A new procedure to extract intramuscular fat (IMF) was developed to minimize sample amount, solvent use and time of analysis. Lyophilised samples (200mg) were accurately weighed in a safe-lock micro test tube, homogenized in 1.5 mL dichloromethane-methanol (8:2) and mixed in a mixer mill (MM400, Retsch technology). The final biphasic system was separated by centrifugation (8 min, 10,000 rpm). The extraction was repeated three times. Solvent was evaporated under nitrogen stream and lipid content was gravimetrically determined. Results from 64 determinations were compared to those obtained with other referred method and showed a linear response over the whole range of IMF content (1.6-6.9 g/100 g sample). Moreover, the analysis with different methodology of six replica from the same sample showed lowest variability (standard deviation intra-method) for the new methodology proposed over a wide range of IMF content. A cost and time efficient lipid extraction procedure was developed without loss of precision and accuracy and with a fatty acid profile comparable to other protocols.

Effects of genotype and dietary oil supplementation on performance, carcass traits, pork quality and fatty acid composition of backfat and intramuscular fat

A 42-day study was conducted to evaluate the effect of genotype: terminal sire line Duroc×F1 (DC×F1); terminal sire line Embrapa MS-115×F1 (MS-115×F1); and MS-115×Moura (MS-115×MO) and three dietary oil sources: soybean; canola; and canola+flax, on performance, carcass traits, pork quality, and fatty acid composition. Genotype affected the technological quality of pork and fatty acid profile. MS-115-sired pigs had better meat color and Duroc-sired pigs had higher intramuscular fat content, more saturated fat and better omega-6/omega-3 ratio. Moura breed influenced positively meat tenderness and intramuscular fat. Diet did not affect the technological quality of the meat. Canola or canola+flax oil diet supplementations increased monounsaturated and C18:3 and decreased C18:2 fatty acids, reducing the omega-6/omega-3 ratio. The best omega-6/omega-3 ratio was obtained through supplementation with canola+flax.

Meat and cancer

An increasing literature associates high intake of meat, especially red meat and processed meat with an increased risk of cancers, especially colorectal cancer. There is evidence that this risk may not be a function of meat per se, but may reflect high-fat intake, and/or carcinogens generated through various cooking and processing methods. The cancer risk may be modulated by certain genotypes. Cancers associated with high meat consumption may be reduced by the addition of anticarcinogens in the diet, especially at the same time as meat preparation or meat consumption, or modification of food preparation methods. Meat contains potential anticarcinogens, including omega-3 polyunsaturated fatty acids, and conjugated linoleic acid (CLA). Red meat, in particular, is an important source of micronutrients with anticancer properties, including selenium, vitamin B6 and B12, and vitamin D. Adjusting the balance between meat and other dietary components may be critical to protecting against potential cancer risks.