Intramuscular fat, the total lipid deposited within skeletal muscle, has been regarded as a potential factor responsible for meat quality in animal production and insulin resistance in humans. The objective of present study was to identify candidate genes which control intramuscular fat accumulation through using animal models. PIC pigs (lean-type) and Rongchang pigs (obese-type) were used. By scanning the mRNA samples of longissimus dorsi muscle with Affymetrix Gene-Chip microarray technology, sus scrofa chloride intracellular channel 5 (CLIC5) was isolated, and its mRNA abundance and protein expression level were reversely related with the intramuscular fat content of pigs. Furthermore, over-expression of CLIC5 dramatically increased the proliferation of 3T3-L1 preadipocytes, while inhibited adipocytic differentiation accompanied by the down-regulation of c/EBPalpha, LPL, and PPARgamma protein. Our results suggest that CLIC5 might be a crucial regulator of adipose accumulation in skeletal muscle of pigs.

Background Superanutriton of selenium (Se) in an effort to produce Se-enriched meat may inadvertently cause lipid accumulation. Se-enriched Cardamine violifolia (SeCv) contains over 80% of Se in organic forms. Objective This study was to determine whether feeding chickens a high dose of SeCv could produce Se-biofortified muscle without altering their lipid metabolism. Methods Day-old male broilers were allocated to 4 groups (6 cages/group and 6 chicks/cage), and were fed either a corn-soy base diet (BD, 0.13–0.15 mg Se/kg), the BD plus 0.5 mg Se/kg as sodium selenite (SeNa) or as SeCv, or the BD plus a low-Se Cardamine violifolia (Cv, 0.21 mg Se/kg). At week 6, concentrations of Se and lipid and expression of selenoprotein and lipid metabolism-related genes were determined in the pectoral muscle and liver. Results The 4 diets showed no effects on growth performance of broilers. Compared with the other 3 diets, SeCv elevated (P < 0.05) Se concentrations in the pectoral muscle and liver by 14.4 to 127%, and decreased (P < 0.05) total cholesterol concentrations by 12.5 to 46.7%, and(or) triglyceride concentrations by 28.8 to 31.1% in the pectoral muscle and(or) liver, respectively. Meanwhile, SeCv enhanced (P < 0.05) muscular α-linolenic acid (80.0%) and hepatic arachidonic acid (58.3%) concentrations compared with SeNa and BD, respectively. SeCv downregulated (P < 0.05) the cholesterol and triglyceride synthesis-related proteins (SREBF2 and DGAT2) and upregulated (P < 0.05) hydrolysis and β-oxidation of fatty acid-related proteins (LPL, FABP1, and CPT1A), SELENOP1 and TXRND activity in the pectoral muscle and(or) liver compared with SeNa. Conclusions Compared with SeNa, SeCv effectively raised Se and reduced lipids in the liver and muscle of broilers. The effect was mediated through the regulation of the cholesterol and triglyceride biosynthesis and utilization-related genes.