Functional and association studies of the cholesteryl ester transfer protein (CETP) gene in a Wannan Black pig model

Some polymorphisms of the human CETP gene are causally and significantly associated with serum lipids levels; however, the information regarding this gene in pigs is sparse. To evaluate the effects of CETP on blood lipid traits and fat deposition in pig, porcine CETP tissue expression patterns were observed by quantitative real‐time polymerase chain reaction (qPCR) first. High expression was detected in liver, spleen, gluteus medius (GM) muscle and backfat. A de novo polymorphism (AF333037:g.795C>T) in the intron 1 region of porcine CETP was identified. This polymorphism was further genotyped by direct sequencing of the PCR products of 390 Wannan Black pigs, a Chinese native breed population. Association analyses at 45 and 300 days of age revealed highly significant associations between CETP genotypes and serum lipid traits. Furthermore, this polymorphism was proved to be associated with differences in liver CETP mRNA levels: pigs at 300 days of age with the TT genotype had higher levels than did those with other genotypes (P = 0.021). Additionally, analysis at 300 days of age showed that GM CETP mRNA expression correlated positively with serum lipids levels as well as with carcass backfat thickness and intramuscular fat content in GM. These results indicate that CETP is involved in serum, adipose and muscle lipid metabolism in pigs. The mechanisms underlying such relationships and their functional implications are worthy of further research.     

Genetics of serum and muscle lipids in pigs

Pork meat is one of the most important sources of animal protein in the human diet. Its nutritional properties are partly determined by intramuscular fat content and composition, with existing general consensus about the detrimental effects of cholesterol and saturated fat on cardiovascular health in humans. Because of their physiological resemblance, pigs can be also used as a valuable animal model to study the genetics of human diseases such as atherosclerosis, obesity and dyslipidaemias. Heritability estimates and QTL maps of porcine muscle and serum lipid traits evidence that a considerable amount of genetic variance determining these phenotypes exists, but its molecular basis remains mostly unknown. The recent advent of high‐throughput genotyping and sequencing technologies has revolutionised the field of animal genomics. With these powerful tools, finding needles in the genomic haystack has become increasingly feasible. However, these methodological advances should not be deemed as magic bullets. The goal of identifying the many polymorphisms that shape the variability of lipid phenotypes is so challenging that success can be achieved only under the scope of large international consortia.     

Reduced protein diets increase intramuscular fat of psoas major,a red muscle,in lean and fatty pig genotypes

The present study aims to assess the effects of pig’s genotype (lean v. fatty) and dietary protein level (control v. reduced) on intramuscular fat (IMF) content, fatty acid composition and fibre profile of psoas major, a representative red muscle in pig’s carcass scarcely studied relative to white longissimus lumborum. The experiment was conducted on 40 intact male pigs (20 Alentejana purebred and 20 Large White×Landrace×Pietrain crossbred) from 60 to 93 kg of live weight. Pigs were divided and allocated to four dietary groups: control protein diet equilibrated for lysine (17.5% of CP and 0.7% of lysine) and reduced protein diet (RPD) not equilibrated for lysine (13.1% of crude protein and 0.4% of lysine) within a 2×2 factorial arrangement (two genotypes and two diets). Alentejana purebred had higher IMF content (15.7%) and monounsaturated fatty acids (MUFA) (8.9%), whereas crossbred pigs had higher PM weight (46.3%) and polyunsaturated fatty acids (PUFA) (20.1%). The genotype also affected colour with higher lightness (15.1%) and yellowness (33.8%) and lower redness (9.9%) scores in crossbred pigs. In line with this, fatty pigs displayed more oxidative fibres (29.5%), whilst lean pigs had more glycolytic (54.4%). Relative to fatty acids, RPD increased MUFA (5.2%) and SFA (3.2%) but decreased PUFA (14.8%). Ultimately, RPD increased IMF content (15.7%) in the red muscle under study, with no impact on glycolytic to oxidative fibre type transformation.     

Mapping and association studies of diabetes related genes in the pig

The mitogen-activated protein kinase 8 (MAPK8), resistin (RETN), 11 beta hydroxysteroid dehydrogenase isoform 1 (HSD11B1) and protein kinase B Akt2 (AKT2) genes are all genes known to affect insulin signalling and have been implicated in the progression of obesity and type 2 diabetes in humans. In this study, polymorphisms in the porcine diabetes related MAPK8, RETN, HSD11B1 and AKT2 genes were identified, mapped and their associations with phenotypic measurements in swine were analysed. Polymorphisms detected in the MAPK8, RETN and HSD11B1 loci were used to genotype a Berkshire-Yorkshire pig breed reference family. Using linkage analysis, RETN, HSD11B1 and MAPK8 genes were mapped to pig chromosomes 2, 9 and 14, respectively, while the AKT2 gene was physically mapped to pig chromosome 6q21. Results presented here suggest associations between the polymorphisms in the MAPK8, RETN and HSD11B1 genes with several phenotypic measurements, including fat deposition traits in the pig. Because these genes have been implicated in obesity and diabetes in humans, and this study suggests associations with fat related traits, further research on these genes in swine may provide useful information on genetic factors underlying lean pork production.     

齐口裂腹鱼和鲤鱼H-FABP基因的克隆及其表达谱

心型脂肪酸结合蛋白（heart fatty acid binding protein, H-FABP）的水平与影响肉质性状的肌内脂肪含量有关,鱼类H-FABP的表达水平对其肌内脂肪含量是否相关仍未见报道.本研究获得齐口裂腹鱼和鲤鱼心脏型脂肪酸结合蛋白基因序列,利用半定量RT-PCR分析其表达特性并测定肌内脂肪含量,比较H-FABP基因在不同生活环境的2种鲤科鱼肌内脂肪沉积中的作用.结果显示,齐口裂腹鱼和鲤鱼H-FABP基因的ORF为402 bp,编码133个氨基酸,它们的氨基酸序列相同,与人、猪、小鼠、斑马鱼、大西洋鲑、虹鳟等的同源性为71.3%~ 90%;H-FABP基因在2种鲤科鱼的心、肌肉、脂肪、肝、脑、脾、肾和鳃等组织中均有表达,肝中的表达量显著高于其它组织（P<0.05）,H-FABP基因的肌肉表达谱在齐口裂腹鱼和鲤鱼中存在明显差异：齐口裂腹鱼中的表达随生长发育呈上升趋势,在大体重鱼（500 g）中的表达显著高于小体重鱼（P<0.05),其表达与肌内脂肪含量呈显著正相关（R=0.370,P<0.05）;H-FABP基因在鲤鱼生长发育中呈下降趋势,而小体重鱼（50~60 g）中的表达显著高于其它大体重鱼(P<0.05),其表达与肌内脂肪含量呈显著负相关（R=-7.083,P<0.01）.据此推测,齐口裂腹鱼和鲤鱼肌肉组织H-FABP基因表达与肌内脂肪关联性的差异可能与2种鱼的生活环境不同有关.     

Malic enzyme 1 genotype is associated with backfat thickness and meat quality traits in pigs

Malic enzyme 1 (ME1) is a part of the tricarboxylate shuttle that provides NADPH and acetyl-CoA required in fatty acid biosynthesis. The pig ME1 locus maps on the proximal end of chromosome 1, where a quantitative trait loci (QTL) affecting fat deposition has been previously described. We amplified fragments of 1457 and 1459 bp that corresponded to the complete coding region and the 3'-untranslated region (UTR), respectively, of the pig ME1 gene. The sequences of these two fragments in pigs from three breeds (Landrace, Large White and Piétrain) contained five single nucleotide polymorphisms (SNP) in the 3'-UTR: C1706T, G1762T, A1807C, C1857A and T1880A. Three haplotypes were found in two generations of a selected Landrace population: H1 (C1706 G1762 A1807 C1857 A1880), H2 (C1706 G1762 A1807 C1857 T1880) and H3 (T1706 T1762 C1807 A1857 T1880). Using Bayesian association analyses, significant associations (highest posterior density at 95%) between ME1 genotype and backfat (BF) thickness at 171 days and muscular pH were found in a Landrace population.     

Genome-wide association study identifies quantitative trait loci regions involved in muscle acidic profile in Large White heavy pigs

The widespread use of genome-wide association studies resulted in the discovery of genomic regions associated with fatty acid (FA) composition in different porcine tissues, but little information exists about the genes involved in FA composition of meat obtained from heavy pigs selected for the production of Italian dry-cured hams. To this objective, we genotyped with a single nucleotide polymorphism (SNP) panel 795 Italian Large White heavy pigs to identify the markers and genomic regions associated with Semimembranosus muscle FA profile. Heritability estimates for intramuscular fat FA profile were of low-to-moderate magnitude, suggesting that these traits may be improved with genomic selection. On the whole, 45 SNPs were significantly associated with 14 FAs, and 4 of them (ALGA008109, ALGA0081097, CASI0010164 and SIRI0000267) were associated with more than 1 FA. The palmitoleic : palmitic and oleic : stearic ratios displayed the highest number of significant markers and the most significant associations (Bonferroni adjusted P < 5.00E−07). Of particular interest, the palmitoleic : palmitic ratio was strongly associated with markers located at 111 to 114 Mb on chromosome 14, in the same chromosomal region where Stearoyl-CoA desaturase Δ9 (SCD) gene is located. Several significant chromosomal regions were found; some of them harbour key genes playing pivotal roles in FA desaturation and elongation, such as SCD and some members of the Elongation of Very Long-Chain FA (ELOVL) gene family. The results suggest that the identification of causal mutations in these regions may provide a set of markers useful for selection schemes aimed at improving FA composition in pork products.     

Effect of sex,dietary glycerol or dietary fat during late fattening,on fatty acid composition and positional distribution of fatty acids within the triglyceride in pigs

The effect of sex, source of saturated fat (lard v. palm oil) and glycerol inclusion in the fattening diet on composition and fatty acid positional distribution in the triglyceride molecule was studied in pigs from 78 to 110 kg BW. Average daily gain and carcass characteristics, including ham and loin weight, were not affected by dietary treatment but sex affected backfat depth (P<0.01). A significant interaction between sex and glycerol inclusion was observed; dietary glycerol increased lean content in gilts but not in barrows (P<0.05 for the interaction). Individual and total saturated fatty acid (SFA) concentrations were greater in barrows than in gilts. In contrast, the concentration of total polyunsaturated fatty acids (PUFA) and of C18:2n-6, C18:3n-3, C20:3n-9 and C20:4n-6 in the intramuscular fat (IMF) was higher (P<0.05) in gilts than in barrows. Sex did not affect total monounsaturated fatty acids (MUFA) concentration in the IMF. The proportion of SFA in the subcutaneous fat (SF) was higher in barrows than in gilts (P<0.001). Within the individual SFA, sex affected only the concentrations of C14:0 and C16:0 (P<0.001). Dietary fat did not affect total SFA or PUFA concentrations of the IMF but the subcutaneous total MUFA concentration tended to be higher (P=0.079) in pigs fed lard than in pigs fed palm oil. Dietary glycerol increased total MUFA and C18:1n-9 concentration in the IMF and increased total MUFA and decreased C18:2n-6, C18:3n-3 and total PUFA concentrations in the SF. The data indicate that altering the fatty acid composition of the triglyceride molecule at the 2-position, by dietary intervention during the fattening phase, is very limited.     

Autofluorescence excitation‐emission matrices as a quantitative tool for the assessment of meat quality

Commercially produced meat is currently graded by a complex and partly subjective multiparameter methodology; a quantitative method of grading, using small samples would be desirable. Here, we investigate the correlation between commercial grades of beef and spectral signatures of native fluorophores in such small samples. Beef samples of different commercial grades were characterized by fluorescence spectroscopy complemented by biochemical and histological assessment. The excitation‐emission matrices of the specimens reveal five prominent native autofluorescence signatures in the excitation range from 250 to 350 nm, derived mainly from tryptophan and intramuscular fat. We found that these signatures reflect meat grade and can be used for its determination.      

Porcine NAMPT gene: search for polymorphism,mapping and association studies

NAMPT encodes an enzyme catalysing the rate‐limiting step in NAD biosynthesis. The extracellular form of the enzyme is known as adipokine visfatin. We detected SNP AM999341:g.669T>C (referred to as 669T>C) in intron 9 and SNP FN392209:g.358A>G (referred to as 358A>G) in the promoter of the gene. RH mapping linked the gene to microsatellite SW944. Linkage analysis placed the gene on the current USDA – USMARC linkage map at position 92 cM on SSC9. Association analyses were performed in a wild boar × Meishan F₂ family (W × M), with 45 traits recorded (growth and fattening, fat deposition, muscling, meat quality, stress resistance and other traits), and in a commercial Landrace × Chinese‐European (LCE) synthetic population with records for 15 traits (growth, fat deposition, muscling, intramuscular fat, meat colour and backfat fatty acid content). In the W × M, SNP 669T>C was associated with muscling, fat deposition, growth and fattening, meat quality and other traits and in the LCE with muscling, meat quality and backfat fatty acid composition. In the W × M, SNP 358A>G was associated with muscling, fat deposition, growth and other traits. After correction for multiple testing, the NAMPT haplotypes were associated in the W × M with, in descending order, muscling (q = 0.0056), growth (q = 0.0056), fat deposition (q = 0.0109), fat‐to‐meat ratio (q = 0.0135), cooling losses (q = 0.0568) and longissimus pH_U (q = 0.0695). The SNPs are hypothesized to be in linkage disequilibrium with a causative mutation affecting energy metabolism as a whole rather than fat metabolism alone.     

Joint analysis of additive,dominant and first‐order epistatic effects of four genes (IGF2, MC4R,PRKAG3 and LEPR) with known effects on fat content and fat distribution in pigs

LEPR, MC4R, IGF2 and PRKAG3 are genes with known effects on fat content and distribution in pig carcass and pork. In a study performed with Duroc × Landrace/Large White pigs, we have found that IGF2 has strong additive effects on several carcass conformational traits and on fatty acid composition in several anatomical locations. MC4R shows additive effects on saturated fatty acid content in several muscles. On the other side, almost no additive effect has been found for PRKAG3 and very few for LEPR. In this work, no dominant effect has been found for any of the four genes. Using a Bayesian Lasso approach, we have been able now to find first‐order epistatic (mainly dominant–additive) effects between LEPR and PRKAG3 for intramuscular fat content and for saturated fatty acid content in L. dorsii, B. femoralis, Ps. major and whole ham. The presence of interactions between genes in the shaping of traits of such importance as intramuscular fat content and composition highlights the complexity of heritable traits and the difficulty of gene‐assisted selection for such traits.     

An effect of a missense mutation in the porcine melanocortin-4 receptor (MC4R) gene on production traits in Polish pig breeds is doubtful

A missense G-A SNP in the porcine melanocortin-4 receptor (MC4R) gene that causes an Asp-Asn substitution at position 298 of the corresponding MC4R protein is considered to be economically important, although published results on its effect are inconsistent. We analysed the association of this MC4R polymorphism with production traits in 679 gilts from two breeds, Polish Large White (PLW) and Polish Landrace (PL), as well as one synthetic line 990. The frequency of the A allele differed significantly among the breeds with frequencies of 0.76, 0.29 and 0.16 in PLW, PL and line 990 respectively. There was no evidence of an effect of this polymorphism on daily food intake, backfat thickness or abdominal fat. The A allele was correlated with higher test daily gains and lower levels of intramuscular fat in PL, and increased levels of intramuscular fat in PLW.     

Evaluation of the Chinese indigenous pig breed Dahe and crossbred Dawu for growth and carcass characteristics, organ weight, meat quality and intramuscular fatty acid and amino acid composition

The objectives of the experiment were to evaluate growth and carcass characteristics, organ weight, meat quality and intramuscular fatty acid (FA) and amino acid composition between the Chinese indigenous pig breed Dahe and the crossbred Dawu. The Dahe pigs had lower average daily gain (P < 0.001) and a higher feed conversion ratio (P < 0.001) compared with the Dawu pigs. The Dahe pigs contained less lean meat percentage (P < 0.001) and more carcass fat percentage (P < 0.001) compared with the Dawu pigs. For organ weight, the Dahe pigs had lower relative heart weight and small intestine weight, respectively, compared with that of the Dawu pigs (P < 0.001). In addition, the Dahe pigs showed higher pH values (at 45 min and 24 h, P < 0.001 and P < 0.001, respectively), higher Marbling score (P < 0.05), lower Minolta L values (at 45 min and 24 h, P < 0.001 and P < 0.05, respectively) and lower muscle fiber area (P < 0.05) than did the Dawu pigs. C18:1, C16:0, C18:0 and C18:2 were the main FAs and nine essential amino acids were found in the Longissimus dorsi of the two breeds.     

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Enhancing healthy fatty acids (FAs) in ewe milk fat and suckling lamb tissues is an important objective in terms of improving the nutritional value of these foods for the consumer. The present study examined the effects of feeding-protected lipid supplements rich in unsaturated FAs on the lipid composition of ewe milk, and subsequently in the muscle and subcutaneous adipose tissues of lambs suckling such milk. Thirty-six pregnant Churra ewes with their new-born lambs were assigned to one of three experimental diets (forage/concentrate ratio 50 : 50), each supplemented with either 3% Ca soap FAs of palm (Control), olive (OLI) or fish (FO) oil. The lambs were nourished exclusively by suckling for the whole experimental period. When the lambs reached 11 kg BW, they were slaughtered and samples were taken from the Longissimus dorsi and subcutaneous fat depots. Although milk production was not affected by lipid supplementation, the FO diet decreased fat content (P<0.001), whereas the OLI milk FA profile resembled that of the Control diet. In contrast, although FO drastically diminished the contents of stearic and oleic acids (P<0.001), all the saturated even-numbered carbon FAs from 6:0 to 14:0 increased (P<0.05). FO also produced the highest levels of c9,t11-18:2 (2.21%) and n-3 FAs, 20:5 n-3 (0.58%), 22:5 n-3 (0.48%) and 22:6 n-3 (0.40%). The high levels of trans-11 18:1 (7.10%) obtained from the FO diet would suggest that Ca soaps only confer partial protection in the rumen. In contrast, the lack of significant differences in trans-10 18:1 levels (P>0.05) and other trans-FAs between Control and FO treatments would indicate that FO treatment does not alter rumen biohydrogenation pathways under the assayed conditions. Changes in dam milk FA composition induced differences in the FA profiles of meat and fat depots of lambs, preferentially incorporated polyunsaturated FAs into the muscle rather than storing them in the adipose tissue. In the intramuscular fat of the FO treatment, all the n-3 FAs reached their highest concentrations: 0.97 (18:3 n-3), 2.72 (20:5 n-3), 2.21 (22:5 n-3) and 1.53% (22:6 n-3). In addition, not only did FO intramuscular fat have the most cis-9, trans-11 18:2 (1.66%) and trans-11 18:1 (3.75%), but also the lowest n-6/n-3 ratio (1.80) and saturated FA content were not affected. Therefore, FO exhibited the best FA profile from a nutritional point of view.     

绵羊肌肉中FAS基因和HSL基因的发育性变化及其对肌内脂肪含量的影响

选取不同日龄的雄性哈萨克羊和新疆细毛羊共54只,屠宰后取背最长肌,用索氏抽提法检测肌内脂肪(intramuscular fat,IMF)含量,用荧光实时定量PCR法检测肌肉脂肪酸合成酶(fatty acid synthase,FAS)和激素敏感脂肪酶(hormone-sensitive lipase,HSL)基因表达的发育性变化,并分析基因表达对肌内脂肪沉积的影响。结果表明:1)随着日龄的增加,雄性哈萨克羊的IMF含量持续上升,各生长时期差异显著(P<0.05),而新疆细毛羊的IMF含量在各生长时期无显著差异(P>0.05)。雄性哈萨克羊的IMF含量30~90日龄期间极显著高于新疆细毛羊(P<0.01)。2)FAS基因mRNA水平在哈萨克羊肌肉中初生时最高(P<0.05),然后随日龄的增加呈下降趋势;在新疆细毛羊肌肉中,FAS mRNA水平表现出"下降-上升-下降-上升"的发育模式,其中60日龄显著高于90日龄(P<0.05),其余日龄之间差异不显著。HSL基因在2品种绵羊肌肉中的表达模式基本类似,在哈萨克羊肌肉中随年龄的增加而下降,初生时的水平显著高于60~90日龄(P<0.05);在新疆细毛羊中30日龄时达到最高(P<0.01),到60日龄时下降到最低(P<0.05),随后保持这种低表达水平。3)FAS和HSL基因mRNA的表达量均与哈萨克羊IMF含量呈负相关,相关系数分别为:r=-0.485(P=0.02),r=-0.423(P=0.05);在哈萨克羊中两基因表达量水平比值(FAS:HSL)与IMF呈极显著负相关r=-0.552(P=0.01)。在新疆细毛羊中两基因的表达水平及比值均与IMF无显著相关性(P>0.05)。     

Identification of a 3.7-Mb region for a marbling QTL on bovine chromosome 4 by identical-by-descent and association analysis

QTL mapping for growth and carcass traits was performed using a paternal half-sib family composed of 325 Japanese Black cattle offspring. Nine QTL were detected at the 1% chromosome-wise significance level at a false discovery rate of less than 0.1. These included two QTL for marbling on BTA 4 and 18, two QTL for carcass weight on BTA 14 and 24, two QTL for longissimus muscle area on BTA 1 and 4, two QTL for subcutaneous fat thickness on BTA 1 and 15 and one QTL for rib thickness on BTA 6. Although the marbling QTL on BTA 4 has been replicated with significant linkages in two Japanese Black cattle sires, the three Q (more marbling) haplotypes, each inherited maternally, were apparently different. To compare the three Q haplotypes in more detail, high-density microsatellite markers for the overlapping regions were developed within the 95% CIs (65 markers in 44–78 cM). A detailed haplotype comparison indicated that a small region (<3.7 Mb) around 46 cM was shared between the Qs of the two sires, whose dams were related. An association of this region with marbling was shown by a regression analysis using the local population, in which the two sires were produced and this was confirmed by an association study using a population collected throughout Japan. These results strongly suggest that the marbling QTL on BTA 4 is located in the 3.7-Mb region at around 46 cM.     

Rearing system and oleic acid supplementation effect on carcass and lipid characteristics of two muscles from an obese pig breed

Quality of pork depends on genotype, rearing and pre- and post-slaughter conditions. However, no information is available on rearing system changes and oleic acid supplementation on carcass characteristics and fatty acid (FA) profile of pork from the Alentejano (AL) pig, an obese breed. This study evaluates the effects of feeding low (LO) or high oleic acid diets (HO) to AL pigs reared in individual pens (IND) or outdoor (OUT) with access to pasture. Carcass composition was obtained and longissimus dorsi and semimembranosus samples were collected to analyse chemical composition and neutral and polar intramuscular lipids FA profile by gas chromatography. Statistical analysis was performed by a two-way ANOVA for rearing system and diet effects. OUT-reared pigs presented leaner carcasses than IND-reared ones. Both muscles presented lower intramuscular lipid content in OUT-reared pigs. Treatments affected the FA profile of muscles. Overall, OUT-reared pigs presented lower n-6/n-3 FA ratios, whereas pigs fed the HO diet exhibited lower saturated fatty acids (SFA), higher monounsaturated fatty acids (MUFA) levels and lower thrombogenic indexes on neutral intramuscular lipids than LO-fed pigs. On the polar fraction, OUT-reared pigs presented lower SAT and n-6/n-3 FA ratio, and higher polyunsaturated fatty acids (PUFA) levels on both muscles. Pigs fed the HO diet exhibited higher MUFA and lower PUFA levels on both muscles, and lower SAT levels on semimembranosus. This study shows rearing system and oleic acid supplementation have complementary effects and influence carcass composition and the nutritional quality of meat.     

Effects of supplementation of rumen-protected choline on growth performance,meat quality and gene expression in longissimus dorsi muscle of lambs

This study determined the effects of rumen-protected choline (RPC) on growth performance, blood lipids, meat quality and expression of genes involved in fatty-acid metabolism in young lambs. A total of 24 Dorper × Hu lambs (about 20 kg body weight) were kept in individual pens and fed diets with 0%, 0.25%, 0.50% and 0.75% RPC for 60 d. Supplementation of 0.25% RPC increased average daily gain of lambs, whereas treatments had no significant effect on feed intake. The pH values of meat were increased at 0.25% RPC and both, dripping loss and shear force of meat, were significantly decreased in RPC-supplemented lambs. No significant changes were observed for dressing percentage and intramuscular fat. RPC supplementations had no significant effect on the concentrations of triglycerides and cholesterols in serum, but the concentration of high-density lipoprotein was decreased at 0.50% RPC and that of low-density lipoprotein was increased at 0.75% RPC. In m. longissimus dorsi, the expressions of cluster of differentiation 36 (CD36), acetyl-CoA carboxylase (ACC) and fatty-acid synthase (FASN) genes were increased at 0.25% RPC. Supplementation of 0.75% RPC increased the expressions of lipoprotein lipase (LPL) and FASN genes, decreased the expression of ACC gene and had no effect on CD36 gene. The results of this study showed that supplementation of 0.25% RPC could promote growth performance of lambs and improve meat quality. This may be mediated by effects on blood lipid profiles and the metabolism of fatty acids in skeleton muscles. However, the beneficial effects of 0.25% RPC supplementation need to be validated with a larger number of animals. Higher doses, particularly 0.75% RPC, showed adverse effects on live weight gain and ACC expression.