Lipid metabolism and secretory function of porcine intramuscular adipocytes compared with subcutaneous and perirenal adipocytes (original) (raw)
Related papers
animal, 2014
The production of pork with high amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the pig industry and consumers. Herein, we question the impact of dietary protein reduction (18% v. 13%) on fat deposition in the subcutaneous adipose tissue (SAT) and longissimus lumborum (LL) muscle using genetically diverse pigs for body fatness (lean v. fat). A clear effect of genotype was observed on plasma insulin (P = 0.004) and leptin (P < 0.001), as well as on backfat thickness (P < 0.001), with the fat pigs having higher values. Accordingly, IMF was higher in the fat pigs, when compared with their lean counterparts (P = 0.003), which was supported by enlarged adipocytes (P < 0.001). The area of lipid droplets within the LL fibres (P = 0.039) and extramyocellular lipids number (P = 0.017) were increased in pigs fed reduced protein diets, regardless of genotype, which is consistent with higher levels of plasma triacylglycerols (P = 0.002). The gene-expression pattern of lipogenic factors in the SAT was distinct from the LL muscle. In the SAT, PPARG expression was similar among genotypes (P > 0.05), whereas in the LL muscle it was higher in the lean pigs (P = 0.023), especially when fed on low protein diet (P = 0.057). The CEBPA and FABP4 mRNA levels were increased in the SAT of fat pigs (P < 0.001), without changes in the LL muscle (P > 0.05). The influence of diet on FABP4 expression in the SAT was dependent on pig's genetic background (P = 0.005). In conclusion, fat deposition was clearly influenced by genotype and, to a lesser extent, by dietary protein level, the SAT being more sensitive than the LL muscle. One can speculate that the pathways involved in lipid metabolism are downregulated in intramuscular adipocytes when compared with SAT fat cells. This result might be a direct consequence of the relatively low proportion of adipocytes found in the LL muscle.
Gene expression phenotypes for lipid metabolism and intramuscular fat in skeletal muscle of cattle
Journal of Animal Science, 2013
Gene expression phenotypes were evaluated for intramuscular fat (IMF) in bovine skeletal muscle as an alternative to traditional estimates of IMF%. Gene expression data from a time course of LM development in high-and low-marbling Bos taurus cattle crosses were compared to identify genes involved in intramuscular adipocyte lipid metabolism with developmentally similar gene expression profi les. Three sets of genes were identifi ed: triacylglyceride (TAG) synthesis and storage, fatty acid (FA) synthesis, and PPARγ-related genes. In an independent analysis in the LM of 48 Bos indicus cattle, TAG and FA gene sets were enriched in the top 100 genes of which expression was most correlated with IMF% (P = 1.2 × 10 −24 and 3.5 × 10 −9 , respectively). In general, genes encoding enzymes involved in the synthesis of FA and TAG in the intramuscular adipocytes were present in the top 100 genes. In B. indicus, effects of a steroid hormone growth promotant (HGP), 2 experimental sites [New South Wales (NSW) and Western Australia (WA)], and 3 tenderness genotypes on the expression levels of genes in the TAG gene set and the correlation of gene expression with IMF% were investigated. Although correlation
Background: This study investigates intramuscular (IM) adipocyte development and growth in the Longissimus muscle (LM) between Wagyu- and Angus-sired steers compared at a similar age and days on feed (DOF) endpoint or similar body weight (BW) endpoint by measuring IM adipocyte cell area and lipid metabolism gene expression. Methods: Angus-sired steers (AN, n=6) were compared with steers from two different Wagyu sires, selected for either growth or marbling, to be compared at a similar DOF (WA-GD, n=5 and WA-MD, n=5) in experiment 1 or BW (WA-GB, n=4 and WA-MB, n=5) in experiment 2, respectively. Results: In experiment 1, WA-MD steers had a greater percentage of IM fat in the LM compared with AN and WA-GD steers. In experiment 2, WA-MB steers had a greater percentage of IM fat in the LM compared with AN and WA-GB steers. The distribution of IM adipocyte area was unimodal at all biopsy collections, with IM adipocyte area becoming progressively larger as cattle age and BW increased (P≤...
Journal of animal science, 2006
Intramuscular fat content is generally associated with improved sensory quality and better acceptability of fresh pork. However, conclusive evidence is still lacking for the biological mechanisms underlying i.m. fat content variability in pigs. The current study aimed to determine whether variations in i.m. fat content of longissimus muscle are related to i.m. adipocyte cellularity, lipid metabolism, or contractile properties of the whole muscle. To this end, crossbred (Large White x Duroc) pigs exhibiting either a high (2.82 +/- 0.38%, HF) or a low (1.15 +/- 0.14%, LF) lipid content in LM biopsies at 70 kg of BW were further studied at 107 +/- 7 kg of BW. Animals grew at the same rate, but HF pigs at slaughter presented fatter carcasses than LF pigs (P = 0.04). The differences in i.m. fat content between the 2 groups were mostly explained by variation in i.m. adipocyte number (+127% in HF compared with LF groups, P = 0.005). Less difference (+13% in HF compared with LF groups, P = ...
Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1995
Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.
Mammalian Genome, 1998
The porcine A-FABP gene (FABP4) was isolated and sequenced to study the role of A-FABP in the differentiation of intramuscular fat (IMF) accretion in pigs. The coding sequence of the porcine A-FABP gene is highly conserved across human, mouse, and rat. Moreover, all the functionally important amino acids are conserved. This high similarity extends into the first 270 bp of the 5Ј upstream region. Within this region, a 56-bp nucleotide sequence was completely identical with the corresponding sequence in the mouse A-FABP gene, which contains the transcription factor binding sites for C/EBP and AP-1, and is implicated in the differentiation-dependent regulation of A-FABP. The A-FABP gene was assigned to porcine Chromosome (Chr) 4 by a porcine sequence-specific PCR on a cell hybrid panel, fully consistent with comparative mapping data with human and mouse. In the first intron of the porcine A-FABP gene, a microsatellite sequence was detected that was polymorphic for all six pig breeds tested. This genetic variation within the A-FABP gene was associated with differences in IMF content and possibly growth in a Duroc population, whereas no effect on backfat thickness and drip loss of the meat were detected. A considerable and significant contrast of approximately 1% IMF was observed between certain genotype classes. We conclude that the A-FABP locus is involved in the regulation of intramuscular fat accretion in Duroc pigs.
Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1996
Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.
BMC Genomics, 2020
Background: This study used a genome-wide screen of gene expression to better understand the metabolic and functional differences between commercially valuable intramuscular fat (IMF) and commercially wasteful subcutaneous (SC) fat depots in Bos taurus beef cattle. Results: We confirmed many findings previously made at the biochemical level and made new discoveries. The fundamental lipogenic machinery, such as ACACA and FASN encoding the rate limiting Acetyl CoA carboxylase and Fatty Acid synthase were expressed at 1.6-1.8 fold lower levels in IMF, consistent with previous findings. The FA elongation pathway including the rate limiting ELOVL6 was also coordinately downregulated in IMF compared to SC as expected. A 2-fold lower expression in IMF of ACSS2 encoding Acetyl Coenzyme A synthetase is consistent with utilisation of less acetate for lipogenesis in IMF compared to SC as previously determined using radioisotope incorporation. Reduced saturation of fat in the SC depot is reflected by 2.4 fold higher expression of the SCD gene encoding the Δ9 desaturase enzyme. Surprisingly, CH25H encoding the cholesterol 25 hydroxylase enzyme was3 6 fold upregulated in IMF compared to SC. Moreover, its expression in whole muscle tissue appears representative of the proportional representation of bovine marbling adipocytes. This suite of observations prompted quantification of a set of oxysterols (oxidised forms of cholesterol) in the plasma of 8 cattle exhibiting varying IMF. Using Liquid Chromatography-Mass Spectrometry (LC-MS) we found the levels of several oxysterols were significantly associated with multiple marbling measurements across the musculature, but (with just one exception) no other carcass phenotypes. Conclusions: These data build on our molecular understanding of ruminant fat depot biology and suggest oxysterols represent a promising circulating biomarker for cattle marbling.
Journal of Food Science, 2013
This study investigated the role of lipogenic enzyme expression in breed-specific fat deposition in pigs. Objectives: (i) determine effect of breed on the relative abundance of the key lipogenic enzymes stearoyl-CoA desaturase (SCD), delta-6 desaturase ( 6D), and fatty acid synthase (FAS) in pig subcutaneous adipose tissue. (ii) Investigate breedspecific relationships between lipogenic enzyme abundance and fatty acid composition. Large White × Piétrain, Piétrain, and Duroc × Piétrain pigs were used. Expression of SCD, 6D, and FAS was analyzed by Western blotting. Fatty acid composition was determined by gas chromatography. FAS protein in Large White × Piétrain pigs was similar to the Piétrain breed, but was significantly higher than Duroc × Piétrain. A positive relationship was found between FAS abundance and the saturated fatty acids (SFAs), for Large White × Piétrain pigs, but not for the other breeds. 6D was significantly higher in Large White × Piétrain compared with Duroc × Piétrain and Piétrain. This was accompanied by significantly higher total n−3 poly-unsaturated fatty acids (PUFAs) in the Large White × Piétrain when compared to the other breeds. Conclusions: (i) increased subcutaneous adipose tissue SFA content in Large White × Piétrain pigs (but not Piétrain and Duroc × Piétrain) is related to increased abundance of FAS protein; (ii) high n−3 PUFA content in Large White × Piétrain pigs is related to activation of 6D protein synthesis; (iii) SCD and 6D abundance does not contribute to between-breed differences in MUFA and n−6 PUFA content of pig subcutaneous adipose tissue.