Genome-wide association analysis identify candidate genes for feed efficiency and growth traits in Wenchang chickens.

BACKGROUND: Wenchang chickens are one of the most popular local chicken breeds in the Chinese chicken industry. However, the low feed efficiency is the main shortcoming of this breed. Therefore, there is a need to find a more precise breeding method to improve the feed efficiency of Wenchang chickens. In this study, we explored important candidate genes and variants for feed efficiency and growth traits through genome-wide association study (GWAS) analysis. RESULTS: Estimates of genomic heritability for growth and feed efficiency traits, including residual feed intake (RFI) of 0.05, average daily food intake (ADFI) of 0.21, average daily weight gain (ADG) of 0.24, body weight (BW) at 87, 95, 104, 113 days of age (BW87, BW95, BW104 and BW113) ranged from 0.30 to 0.44. Important candidate genes related to feed efficiency and growth traits were identified, such as PLCE1, LAP3, MED28, QDPR, LDB2 and SEL1L3 genes. CONCLUSION: The results identified important candidate genes for feed efficiency and growth traits in Wenchang chickens and provide a theoretical basis for the development of new molecular breeding technology.

Copy number variations within fibroblast growth factor 13 gene influence growth traits and alternative splicing in cattle.

Previous researches revealed a copy number variation (CNV) region in the bovine fibroblast growth factor 13 (FGF13) gene. However, its effects remain unknown. This study detected the various copy number types in seven Chinese cattle breeds and analysed their population genetic characteristics and effects on growth traits and transcription levels. Copy number Loss was more frequent in Caoyuan Red cattle and Xianan cattle than in the other breeds. Association analysis between CNV and growth traits of Qinchuan indicated that the CNV was significantly related to chest depth, hip width and hucklebone width (P < 0.05). Additionally, the growth traits of individuals with copy number Loss were significantly inferior to those with copy number Gain or Median (P < 0.05). Besides, we found two splicing isoforms, AS1 and AS2, in FGF13 gene, which resulted from alternative 5' splicing sites of intron 1. These isoforms showed varied expression levels in various tissues. Moreover, CNV was significantly and negatively associated with the mRNA expression of AS1 (r = -0.525, P < 0.05). The CNVs in bovine FGF13 gene negatively regulated growth traits and gene transcription. These observations provide new insights into bovine FGF13 gene, delivering potentially useful information for future Chinese cattle breeding programs.

The Construction of lncRNA/circRNA-miRNA-mRNA Networks Reveals Functional Genes Related to Growth Traits in Schima superba.

Schima superba is a precious timber and fire-resistant tree species widely distributed in southern China. Currently, there is little knowledge related to its growth traits, especially with respect to molecular breeding. The lack of relevant information has delayed the development of modern breeding. The purpose is to identify probable functional genes involved in S. superba growth through whole transcriptome sequencing. In this study, a total of 32,711 mRNAs, 525 miRNAs, 54,312 lncRNAs, and 1522 circRNAs were identified from 10 S. superba individuals containing different volumes of wood. Four possible regulators, comprising three lncRNAs, one circRNA, and eleven key miRNAs, were identified from the regulatory networks of lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA to supply information on ncRNAs. Several candidate genes involved in phenylpropane and cellulose biosynthesis pathways, including Ss4CL2, SsCSL1, and SsCSL2, and transcription factors, including SsDELLA2 (SsSLR), SsDELLA3 (SsSLN), SsDELLA5 (SsGAI-like2), and SsNAM1, were identified to reveal the molecular regulatory mechanisms regulating the growth traits of S. superba. The results not merely provide candidate functional genes related to S. superba growth trait and will be useful to carry out molecular breeding, but the strategy and method also provide scientists with an effective approach to revealing mechanisms behind important economic traits in other species.

Regional testing of triploid hybrid clones of populus tomentosa.

BACKGROUND: Triploid Populus tomentosa, a timber tree species, has been widely planted in northern China owing to its potential high yields and high wood quality. Though genetic variances in growth traits and wood properties have been reported across several planting sites, regional testing of triploid hybrid clones of P. tomentosa has not been conducted on a large scale. RESULTS: Ten 5-year clonal trials were used to evaluate the inheritance of growth traits, to determine suitable deployment zones, and to identify optimal triploid clones at each experimental site to determine the clones that would be suitable at all sites. A total of 2,430 trees from nine triploid hybrid clones were sampled during the ten trials. The clonal and site effects and clone × site interactions were highly significant (P < 0.001) for all the studied growth and yield traits. The estimated repeatability of means for diameter at breast height (DBH) and tree height (H) was 0.83, which was slightly higher than for stem volume (SV) and estimated stand volume (ESV) (0.78). The Weixian (WX), Gaotang (GT), and Yanzhou (YZ) sites were each considered to be suitable deployment zones, and the Zhengzhou (ZZ), Taiyuan (TY), Pinggu (PG), and Xiangfen (XF) sites were found to be the optimal deployment zones. The TY and ZZ sites were the best discriminative environments, and the GT and XF sites were the best representative environments. GGE pilot analysis revealed that yield performance and stability were significantly different among all the studied triploid hybrid clones across the ten test sites. It was therefore necessary to develop a suitable triploid hybrid clone that could do well at each site. Taking into account both yield performance and stability, the triploid hybrid clone S2 was determined to be an ideal genotype. CONCLUSIONS: For triploid hybrid clones, the WX, GT, and YZ sites represented suitable deployment zones and the ZZ, TY, PG, and XF sites represented optimal deployment zones. Yield performance and stability were significantly different among all the studied triploid hybrid clones across the ten test sites. Developing a suitable triploid hybrid clone that could do well at all sites was therefore desirable.

Comparison of the growth performance between pure Moghani sheep and crosses with Texel or Booroola sheep carrying major genes contributing to muscularity and prolificacy.

This study aimed to compare growth performance between Moghani sheep and crossbred lambs resulting from crossbreeding between Moghani pure breed ewes and the lines of rams e.g., Texel Tamlet, Texel Dalzell, Booroola Merino, and Booroola Romney. The first visible phenotypic characteristic was the presence of lean tail in all F1 crossbred lambs, whereas Moghani pure sheep is a well-known large fat-tailed breed. Moreover, the first generation of backcross (BC1) lambs from mating four types of F1 crossbred rams with Moghani pure ewes revealed lean-tailed to short fat-tailed. Comparative results showed that the F1 crossbred lambs had significantly (p < 0.0001) greater birth weight (BW) than the Moghani pure breed lambs. Despite no significant differences observed between Moghani pure breed sheep and its F1 crossbred lambs for body weight at pre-weaning, but F1 crossbred lambs achieved significantly (p < 0.0001) greater body weight after weaning compared to Moghani sheep. The growth performance of BC1 lambs was outperformed than F1 crossbred and Moghani sheep. These results encourage the continuation of the Moghani sheep crossbreeding programs to improve overall lamb growth, particularly post-weaning and to benefit from a better reproductive efficiency by elimination or reduction of the fat tail.

Identification of genes related to growth traits from transcriptome profiles of duck breast muscle tissue.

The growth and development of duck skeletal muscle is an important economic trait that is genetically regulated. The internal mechanism underlying the regulation of skeletal muscle growth and development in ducks remains unclear. The purpose of this study was to identify candidate genes related to the growth of duck skeletal muscle. RNA-sequencing technology was used to compare the transcriptome of duck breast muscles in an F2 population with the high breast muscle rate (HB) and the low breast muscle rate (LB). A total of 14,522 genes were confirmed to be expressed in the breast muscle, and 173 differentially expressed genes (DEGs) were identified between the HB and LB groups. Functional analysis showed that these DEGs were mainly involved in biological processes and pathways of fat metabolism and muscle growth, especially the FABP3 and MYL4 involved in the PPAR signaling pathway and cardiac muscle contraction pathway. These findings deepened our understanding of the molecular mechanisms involved in muscle growth in ducks and provided a theoretical basis for improving duck production and breeding of ducks.

Investigation of Genetic Effects of Nucleotide Variants Within the Goat PRNT Gene on Growth Performance.

Our previous study has firstly pointed that three nucleotide variants (g.-11C > T, g.117A > G, and g.149C > T) of the goat PRNT gene can significantly influence litter size. Given litter size is positively correlated with growth performance, we consider whether the PRNT gene also acts on the growth performance in goats. In this work, a correlation analysis among different litter size types and growth traits of Shaanbei white cashmere (SBWC) goats was performed, and results showed that a positive correlation did exist in our detected population (P < 0.01). Then, the association among different genotypes of three variations and goat growth performance was measured. Our results pointed to g.117A > G being significantly associated with the cannon circumference (P = 4.60E-05) while no significant effect was found between another two SNPs and growth traits after the Bonferroni's correction (P*n < 0.05). Together, this is the first report about the influence of the PRNT gene on the growth of goat and g.117A > G can be regarded as a possible DNA marker applying for MAS breeding.

Age-Dependent Growth-Related QTL Variations in Pacific Abalone, Haliotis discus hannai.

Pacific abalone is a high-value, commercially important marine invertebrate. It shows low growth as well as individual and yearly growth variation in aquaculture. Marker-assisted selection breeding could potentially resolve the problem of low and variable growth and increase genetic gain. Expression of quantitative trait loci (QTLs) for growth-related traits, viz., body weight, shell length, and shell width were analyzed at the first, second, and third year of age using an F1 cross population. A total of 37 chromosome-wide QTLs were identified in linkage groups 01, 02, 03, 04, 06, 07, 08, 10, 11, 12, and 13 at different ages. None of the QTLs detected at any one age were expressed in all three age groups. This result suggests that growth-related traits at different ages are influenced by different QTLs in each year. However, multiple-trait QTLs (where one QTL affects all three traits) were detected each year that are also age-specific. Eleven multiple-trait QTLs were detected at different ages: two QTLs in the first year; two QTLs in the second year; and seven QTLs in the third year. As abalone hatcheries use three-year-old abalone for breeding, QTL-linked markers that were detected at the third year of age could potentially be used in marker-assisted selection breeding programs.

Analysis of Growth Trajectories and Verification of Related SNPs in Populus deltoides.

As an important timber genus with high economic and ecological values, Populus is a model for dissecting the genetic architecture of growth traits in perennial forest trees. However, the genetic mechanisms of longitudinal growth traits in poplar remain incompletely understood. In this study, we conducted longitudinal genetic analysis of height and diameter at breast height (DBH) in eleven-year poplar clones using ultra-deep sequencing datasets. We compared four S-shaped growth models, including asymptotic, Gompertz, logistic, and Richard, on eleven-year height and DBH records in terms of five metrics. We constructed the best-fitting growth model (Richard) and determined poplar ontogenetic stages by virtue of growth curve fitting and likelihood ratio testing. This study provides some scientific clues for temporal variation of longitudinal growth traits in Populus species.

Growth rate and efficiency-related traits in Kermani lambs: estimations of (co)variance components and genetic parameters.

Using Kermani sheep, the current study estimated (co)variance components and genetic parameters for average daily gain, Kleiber's ratio, growth efficiency, and relative growth rate. Data were analyzed by the average information restricted maximum likelihood (AI-REML) method using six animal models with different combinations of direct and maternal effects. The best-fitting model was determined after testing for improvement in log-likelihood values. The estimates of h2 for average daily gain (ADG), Klieber's ratio (KR), growth efficiency (GE), and relative growth rate (RGR) in pre- and post-weaning phases were 0.13 ± 0.6 and 0.17 ± 0.02, 0.12 ± 0.04, and 0.16 ± 0.03; 0.05 ± 0.05 and 0.07 ± 0.03 and 0.06 ± 0.02 and 0.07 ± 0.01, respectively. Maternal heritabilities (m2) ranged from 0.03 ± 0.01 for relative growth rate in pre-weaning phase to 0.11 ± 0.04 for average daily gain in post-weaning period. The maternal permanent environmental component (Pe2) accounted for 3 to 13% to the phenotypic variance for all the studied traits. Estimated values of additive coefficient of variations (CVA) ranged from 2.79% for relative growth rate at 6 months of age to 23.74% for growth efficiency at yearling age. Genetic and phenotypic correlations among traits were ranged from -0.687 to 0.946 and -0.648 to 0.918, respectively. The result indicated that selection for growth rate and efficiency-related traits would also be less effective in achieving genetic change, because there was little additive genetic variation among Kermani lambs.

Characterization and expression of MUSTN1 gene from different duck breeds.

Muscle growth rate and muscle mass are important economic traits in animal production. Musculoskeletal embryonic nuclear protein 1 (MUSTN1) gene has been implicated in myofusion as well as skeletal muscle growth and repair; however, the exact role and expression of MUSTN1 in different duck breeds are not fully understood. To gain insights into the biological functions of MUSTN1 in skeletal muscle development, the MUSTN1 coding sequence of Pekin ducks (BD) and Cherry Valley ducks (CD) was compared to various other animals using the Editseq in DNAstar and MEGA software. The results showed that the duck had the highest homology with chicken. The RT-qPCR and western blot were performed to estimate the mRNA and protein expression pattern of MUSTN1 in leg muscles of BD and CD at 3 and 6-weeks of age. At 3 weeks of age, the mRNA and protein expression levels of MUSTN1 were significantly higher in BD than in CD (p < 0.05). At 6 weeks, the expression level was higher in BD than in CD. In conclusion, MUSTN1 might play a key role in positive regulation of muscle growth and development of ducks.

Genotype-environment interaction and stability of fiber properties and growth traits in triploid hybrid clones of Populus tomentosa.

BACKGROUND: Clones provide a sensitive method for evaluating genotypic stability and detecting genotype-environment (G × E) interactions because of non-additive genetic effects among clones and there being no genetic effect among ramets of an ortet. With this study, we aimed to confirm and expand earlier findings, estimate stability parameters, and provide accurate estimates of clonal repeatabilities and genetic gains for a triploid breeding program of P. tomentosa Carr. RESULTS: Six 5-year-old clonal trials established in Northern China were used to determine the clonal variation, clone × site interactions, and the stability parameters of fiber properties of wood and growth traits. 360 trees from ten hybrid clones were collected from six sites. The clonal and site effects had a highly significant effect (P < 0.001) for all studied traits. While the clone × site interactions had a highly significant effect (P < 0.001) on fiber length (FL), coarseness (C), and tree growth (tree height [H], diameter at breast height [DBH] and stem volume [SV]), and a moderate effect (P < 0.05) on fiber width (FW) and fiber length/width (FL/W). For FL and SV, most of the triploid hybrid clones had higher reaction norms to the improvement in growth conditions and higher phenotypic plasticity. The estimated clonal repeatability of FW (0.93) was slightly higher than for FL (0.89), FL/W (0.83), C (0.91), DBH (0.76), H (0.85), and SV (0.80). Three clonal testing sites were sufficient to estimate quantitative parameters of fiber properties, however, more clonal testing sites would help improve the accuracy of quantitative parameters of the growth traits. CONCLUSIONS: Our results highlight that accurate estimation of quantitative parameters for growth traits in triploid hybrid clones of P. tomentosa requires more clonal testing sites than the fiber properties.

A 5-bp mutation within MSTN/GDF8 gene was significantly associated with growth traits in Inner Mongolia White Cashmere goats.

Myostatin (MSTN) gene, also known as growth and differentiation factor 8 (GDF8) gene, is a negative regulator of skeletal muscle growth and development, especially the number, size and type of muscle fibers. Its mutations contribute to the double-muscling (DBM) phenomenon which significantly increases the muscle mass. Hence, variations within MSTN/GDF8 gene receive so much attention in several kinds of species such as bovines, poultries, goats, sheep, horses. A 5-base pairs (bp) indel in the 5' untranslated region (5'UTR) of goat MSTN/GDF8 was verified to be significantly associated with growth traits except Inner Mongolia White Cashmere (IMWC) goats. Given that almost all sample sizes were below 150, we enlarged sample sizes to more than 500 to uncover the association between the 5-bp indel and growth traits in IMWC goats. Only two genotypes (deletion/deletion (DD) and insertion/deletion (ID)) were found, and DD genotypes were dominant genotypes. The detected locus displayed low genetic diversity (PIC = 0.090). Interestingly, the association analyses revealed that the 5-bp indel had a significant effect on the chest depth (p = 0.003), and DD genotypes were dominant genotypes. Hinted that the 5-bp indel could act as an effective marker in molecular marker-assisted selection (MAS) processes for selection of excellent goat individuals.

Genetic variants in MYF5 affected growth traits and beef quality traits in Chinese Qinchuan cattle.

Myogenic factor 5 plays actively roles in the regulation of myogenesis. The aims of this study are to identify the evolution information of MYF5 protein among 10 domestic and mammalian animals, to uncover the expression patterns of MYF5 gene in calves and adults of Qinchuan cattle, and to expose the genetic variants of the MYF5 gene and explore its effect on cattle growth traits and beef quality traits in Qinchuan cattle. The bioinformatics results showed that the MYF5 proteins highly conserved in different mammalian or domestic animals apart from chicken. The expression level of MYF5 gene in the heart, muscle, lung, large intestine and liver was greater than that of other tissues. PCR amplicons sequencing identified four novel SNPs at g.5738A>G, g.5785C>T and g.5816A>G in the 3rd exon region and g.6535A>G in the 3' UTR. Genotypic frequencies of g.5785C>T was harshly deviated from the HWE (P < .05). Genetic diversity was low or intermediate for the four SNPs and those SNPs were in the weak linkage disequilibrium. Association analysis results indicated g.5785C>T, g.5816A>G and g.6535A>G significant effect on growth performance and beef quality traits of Qinchuan cattle. H1H3 diplotype had greater body size and better beef quality. All the results implicate that the MYF5 gene might be applied as a promising candidate gene in Qinchuan cattle breeding.

Genotype frequency distributions of 28 SNP markers in two commercial lines and five Chinese native chicken populations.

BACKGROUND: Modern breeding in the poultry industry mainly aims to produce high-performance poultry lines and breeds in two main directions of productivity, meat and eggs. To understand more about the productive potential of lowly selected Chinese native chicken populations, we selected 14 representative SNP markers strongly associated with growth traits or carcass traits and 14 SNP markers strongly associated with egg laying traits through previous reports. By using the MassArray technology, we detected the genotype frequency distributions of these 28 SNP markers in seven populations including four lowly selected as well as one moderately selected Sichuan native chicken populations, one commercial broiler line and one commercial layer line. RESULTS: Based on the genotype frequency distributions of these 28 SNP markers in 5 native chicken populations and 2 commercial lines, the results suggested that these Chinese indigenous chicken populations have a relatively close relationship with the commercial broiler line but a marked distinction from the commercial layer line. Two native chicken breeds, Shimian Caoke Chicken and Daheng Broilers, share similar genetic structure with the broiler line. CONCLUSIONS: Our observations may help us to better select and breed superior domestic chickens and provide new clues for further study of breeding programs in local chicken populations.

Estimation of (co)variance components for birth weight in Nellore cattle using alternative data editing criteria.

The aim of this study was to estimate the (co)variance components and breeding values for birthweight (BW) in Nellore cattle by considering or not identical weights that exhibit a high frequency within the contemporary group (CG). A total of 175,258 BW records of Nellore cattle born between 2002 and 2018 were used. The CG was formed by farm, year of birth, sex and feeding regime at birth. CGs with more than 16% of identical BW values were eliminated, generating a data file called BWd. Another file was created without removing these animals (BWt). A mixed linear model was used for statistical analysis, which included fixed and random effects. In both data files analysed, single-trait analysis was performed by Bayesian inference. The mean direct and maternal heritability for BW and the correlation between direct and maternal effects were 0.27, 0.07 and -0.07 for BWt, respectively, and 0.30, 0.093 and -0.07 for BWd. This method should affect the estimation of genetic merits of animals for BW, providing greater safety in the choice of sires.

Association of growth traits with a structural variation downstream of the KCNJ11 gene: a large population-based study in chickens.

1. The potassium voltage-gated channel subfamily J member 11 gene (KCNJ11) is involved in the insulin secretion pathway. Studies have shown that mutation in this gene is associated with muscle weakness. The objective of the present study was to establish the association between KCNJ11 gene polymorphism and chicken growth performance and to analyse its expression pattern. 2. A novel 163-bp insertion/deletion (indel) polymorphism was identified in the region downstream of the KCNJ11 gene in 2330 individuals from ten populations by polymerase chain reaction (PCR). An F2 resource population was used to investigate the genetic effects of the chicken KCNJ11 gene. Association analysis showed that the indel was significantly associated with chicken growth traits and that the phenotypic value of the ins-ins (II) genotype is higher than that of the ins-del (ID) and del-del (DD) genotypes. 3. Gene expression for different genotypes showed that birds carrying the II allele had a higher expression level than the DD genotypes. Analysis of tissue and spatiotemporal expression patterns indicated that the KCNJ11 gene was highly expressed in muscle tissues, with the highest levels in muscle tissue at one week of age, and that a 10% crude protein diet reduced the expression of this gene, average daily gain and muscle fibre diameter. 4. The results suggested that this novel 163-bp indel has the potential to become a new target for marker-assisted selection.

A longitudinal quantitative trait locus mapping of chicken growth traits.

Since the growth traits of chickens are largely related to the production of meat and eggs, it is definitely important to understand genetic basis of growth traits. Although many quantitative trait loci (QTLs) that affect growth traits have recently been reported in chickens, little is known about genetic architecture of growth traits across all growth stages. Therefore, we conducted a longitudinal QTL study of growth traits measured from 0 to 64 weeks of age using 134 microsatellite DNA markers on 26 autosomes from 406 F2 females, which resulted from an intercross of Oh-Shamo and White Leghorn chicken breeds. We found 27 and 21 independent main-effect QTLs for body weight and shank length, respectively. Moreover, 15 and 4 pairs of epistatic QTLs were found for body weight and shank length, respectively. Taken together, the present study revealed 48 QTLs for growth traits on 21 different autosomes, and these loci clearly have age-specific effects on phenotypes throughout stages that are important for meat and egg productions. Approximately 60% of Oh-Shamo-derived alleles increased the phenotypic values, corresponding to the fact that Oh-Shamo traits were higher than those of White Leghorn. On the other hand, remaining Oh-Shamo alleles decreased the phenotypic values. Our results clearly indicated that the growth traits of chickens are regulated by several main and epistatic QTLs that are widely distributed in the chicken genome, and that the QTLs have age-dependent manners of controlling the traits. This study implies importance of not only cross-sectional but also longitudinal growth data for further understanding of the complex genetic architecture in animal.

High-density genetic map construction and quantitative trait loci identification for growth traits in (Taxodium distichum var. distichum × T. mucronatum) × T. mucronatum.

BACKGROUND: 'Zhongshanshan' is the general designation for the superior interspecific hybrid clones of Taxodium species, which is widely grown for economic and ecological purposes in southern China. Growth is the priority objective in 'Zhongshanshan' tree improvement. A high-density linkage map is vital to efficiently identify key quantitative trait loci (QTLs) that affect growth. RESULTS: In total, 403.16 Gb of data, containing 2016,336 paired-end reads, was obtained after preprocessing. The average sequencing depth was 28.49 in T. distichum var. distichum, 25.18 in T. mucronatum, and 11.12 in each progeny. In total, 524,662 high-quality SLAFs were detected, of which 249,619 were polymorphic, and 6166 of the polymorphic markers met the requirements for use in constructing a genetic map. The final map harbored 6156 SLAF markers on 11 linkage groups, and was 1137.86 cM in length, with an average distance of 0.18 cM between adjacent markers. Separate QTL analyses of traits in different years by CIM detected 7 QTLs. While combining multiple-year data, 13 QTLs were detected by ICIM. 5 QTLs were repeatedly detected by the two methods, and among them, 3 significant QTLs (q6-2, q4-2 and q2-1) were detected in at least two traits. Bioinformatic analysis discoveried a gene annotated as a leucine-rich repeat receptor-like kinase gene within q4-2. CONCLUSIONS: This map is the most saturated one constructed in a Taxodiaceae species to date, and would provide useful information for future comparative mapping, genome assembly, and marker-assisted selection.

Comparative performance of growth, vertebral structure and muscle composition in diploid and triploid Paralichthys olivaceus.

Growth, skeletal structure and muscle composition of cold-shock-induced triploid olive flounder Paralichthys olivaceus were investigated. The average values of total length and total weight of triploids were higher than those of diploids from 5 to 11 months posthatch (mph). The growth difference disappeared after 11 mph. The skeletal structure of flounder at 11 mph was observed by X-ray imaging method. There are four kinds of vertebral deformity including vertebrae fusion, one-sided compression, two-sided compression and vertically shifted. The trunk region (V8-18) and tailing end of the vertebral column were the predominant locations of deformity. In general, the frequencies of vertebral deformities in triploids (60.0%) were higher than those in diploids (33.3%, p < 0.05). Both the number of fish with deformed vertebrae and the average frequencies of deformed vertebrae in triploids were significantly higher than those in diploids (p < 0.05). The muscle tissues of diploid and triploid flounder at 11 mph contain the same types of fatty acid and free amino acid profiles. The number of fatty acids with significant higher contents in diploids and triploids was one and ten, respectively (p < 0.05). The contents of free amino acids showed no difference between triploid and diploid fish.