Examining the Genetic Background of Porcine Muscle Growth and Development Based on Transcriptome and miRNAome Data

Comparative muscle transcriptome of Mali and Hampshire breeds of pigs: a preliminary study

Muscle development is an important priority of pig breeding programs. There is a considerable variation in muscularity between the breeds, but the regulation mechanisms of genes underlying myogenesis are still unclear. Transcriptome data from two breeds of pigs with divergent muscularity (Mali and Hampshire) were integrated with histology, immunofluorescence and meat yield to identify differences in myogenesis during the early growth phase. The muscle transcriptomics analysis revealed 17,721 common, 1413 and 1115 unique transcripts to Hampshire and Mali, respectively. This study identified 908 differentially expressed genes (p < 0.05; log2FC > ±1) in the muscle samples, of which 550 were upregulated and 358 were downregulated in Hampshire pigs, indicating differences in physiological process related to muscle function and development. Expression of genes related to myoblast fusion (MYMK), skeletal muscle satellite cell proliferation (ANGPT1, CDON) and growth factors (HGF, IGF1, IGF2) were higher in Hampshire than Mali, even though transcript levels of several other myogenesis-related genes (MYF6, MYOG, MSTN) were similar. The number of fibers per fascicle and the expression of myogenic marker proteins (MYOD1, MYOG and PAX7) were more in Hampshire as compared to Mali breed of pig, supporting results of transcriptome studies. The results suggest that differences in muscularity between breeds could be related to the regulation of myoblast fusion and myogenic activities. The present study will help to identify genes that could be explored for their utility in the selection of animals with different muscularities.

Benchmarking of bioinformatics tools for NGS-based microRNA profiling with RT-qPCR method

MicroRNAs are vital gene expression regulators, extensively studied worldwide. The large-scale characterization of miRNAomes is possible using next-generation sequencing (NGS). This technology offers great opportunities, but these cannot be fully exploited without proper and comprehensive bioinformatics analysis. This may be achieved by the use of reliable dedicated software; however, different programs may generate divergent results, leading to additional discrepancies. Thus, the aim of this study was to compare three bioinformatic algorithms dedicated to NGS-based microRNA profiling and validate them using an alternative method, namely RT-qPCR. The comparison analysis revealed differences in the number and sets of identified miRNAs. The qPCR confirmed the expression of the investigated microRNAs. The correlation analysis of NGS and qPCR measurements showed strong and significant coefficients for a subset of the tested miRNAs, including those detected by all three algorithms. Single miRNA variants (isomiRs) showed different levels of correlation with the qPCR data. The obtained results revealed the good performance of all tested programs, despite the observed differences. Moreover, they implied that some specific miRNAs may be differentially estimated using NGS technology and the qPCR method, regardless of the used bioinformatics software. These discrepancies may stem from many factors, including the composition of the isomiR profile, their abundance, length, and investigated species. In conclusion, in this study, we shed light on the bioinformatics aspects of miRNAome profiling, elucidating its complexity and pinpointing potential features influencing validation. Thus, qPCR validation results should be open to interpretation when not fully concordant with NGS results until further, additional analyses are conducted.

Transcriptional atlas analysis from multiple tissues reveals the expression specificity patterns in beef cattle

Background

A comprehensive analysis of gene expression profiling across tissues can provide necessary information for an in-depth understanding of their biological functions. We performed a large-scale gene expression analysis and generated a high-resolution atlas of the transcriptome in beef cattle.

Results

Our transcriptome atlas was generated from 135 bovine tissues in adult beef cattle, covering 51 tissue types of major organ systems (e.g., muscular system, digestive system, immune system, reproductive system). Approximately 94.76% of sequencing reads were successfully mapped to the reference genome assembly ARS-UCD1.2. We detected a total of 60,488 transcripts, and 32% of them were not reported before. We identified 2654 housekeeping genes (HKGs) and 477 tissue-specific genes (TSGs) across tissues. Using weighted gene co-expression network analysis, we obtained 24 modules with 237 hub genes (HUBGs). Functional enrichment analysis showed that HKGs mainly maintain the basic biological activities of cells, while TSGs were involved in tissue differentiation and specific physiological processes. HKGs in bovine tissues were more conserved in terms of expression pattern as compared to TSGs and HUBGs among multiple species. Finally, we obtained a subset of tissue-specific differentially expressed genes (DEGs) between beef and dairy cattle and several functional pathways, which may be involved in production and health traits.

Conclusions

We generated a large-scale gene expression atlas across the major tissues in beef cattle, providing valuable information for enhancing genome assembly and annotation. HKGs, TSGs, and HUBGs further contribute to better understanding the biology and evolution of multiple tissues in cattle. DEGs between beef and dairy cattle also fill in the knowledge gaps about differential transcriptome regulation of bovine tissues underlying economically important traits.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01269-4.

In Utero Fetal Weight in Pigs Is Regulated by microRNAs and Their Target Genes

Impaired skeletal muscle growth in utero can result in reduced birth weight and poor carcass quality in pigs. Recently, we showed the role of microRNAs (miRNAs) and their target genes in prenatal skeletal muscle development and pathogenesis of intrauterine growth restriction (IUGR). In this study, we performed an integrative miRNA-mRNA transcriptomic analysis in longissimus dorsi muscle (LDM) of pig fetuses at 63 days post conception (dpc) to identify miRNAs and genes correlated to fetal weight. We found 13 miRNAs in LDM significantly correlated to fetal weight, including miR-140, miR-186, miR-101, miR-15, miR-24, miR-29, miR-449, miR-27, miR-142, miR-99, miR-181, miR-199, and miR-210. The expression of these miRNAs decreased with an increase in fetal weight. We also identified 1315 genes significantly correlated to fetal weight at 63 dpc, of which 135 genes were negatively correlated as well as identified as potential targets of the above-listed 13 miRNAs. These miRNAs and their target genes enriched pathways and biological processes important for fetal growth, development, and metabolism. These results indicate that the transcriptomic profile of skeletal muscle can be used to predict fetal weight, and miRNAs correlated to fetal weight can serve as potential biomarkers of prenatal fetal health and growth.

Comparative Analysis of MicroRNA Expression Profiles Between Skeletal Muscle- and Adipose-Derived Exosomes in Pig

Skeletal muscle and adipose tissues are both involved in regulation of metabolism. In the skeletal muscle-adipose tissue crosstalk, exosomes may play an important role but the main components of exosomes are not clear. In this study, we found skeletal muscle-derived exosomes can inhibit adipogenesis of porcine preadipocytes. We identified microRNA expression profiles of muscle exosomes and adipose exosomes by high-throughput sequencing. There were 104 (both novel and known microRNAs) microRNAs differentially expressed (DE miRNAs) between M-EXO (muscle-derived exosomes) and A-EXO (adipose–derived exosomes) groups. A total of 2,137 target genes of DE miRNAs for M-EXO and 2,004 target genes of DE miRNAs for A-EXO were detected. Bioinformatic analyses revealed that some DE miRNAs of M-EXO (especially miR-221-5p) were mainly enriched in lipid-related metabolism processes. The findings may serve as a fundamental resource for understanding the detailed functions of exosomes between the skeletal muscle-adipose crosstalk and the potential relationship between skeletal muscle atrophy and obesity.

Dynamic transcriptome and histomorphology analysis of developmental traits of hindlimb thigh muscle from Odorrana tormota and its adaptability to different life history stages

Background

Systematic studies on the development and adaptation of hindlimb muscles in anura amphibians are rare. Here, we integrated analysis of transcriptome and histomorphological data for the hindlimb thigh muscle of Odorrana tormota (concave-eared torrent frog) at different developmental stages, to uncover the developmental traits of hindlimb thigh muscle from O. tormota and its adaptability to different life history stages.

Results

The development of hindlimb thigh muscle from O. tormota has the following characteristics. Before metamorphosis, myogenous cells proliferate and differentiate into myotubes, and form 11 muscle groups at G41; Primary myofibers and secondary myofibers appeared during metamorphosis; 11 muscle groups differentiated continuously to form myofibers, accompanied by myofibers hypertrophy after metamorphosis; During the growth process of O. tormota from G42 to G46, there were differences between the sexes in the muscle groups that differentiate into muscle fibers, indicating that there was sexual dimorphism in the hindlimb thigh muscles of O. tormota at the metamorphosis stages. Some genes and pathways related to growth, development, and movement ability of O. tormota at different developmental stages were obtained. In addition, some pathways associated with adaptation to metamorphosis and hibernation also were enriched. Furthermore, integrated analysis of the number of myofibers and transcriptome data suggested that myofibers of specific muscle groups in the hindlimbs may be degraded through lysosome and ubiquitin pathways to transform into energy metabolism and other energy-related substances to meet the physiological needs of hibernation.

Conclusions

These results provide further understanding the hindlimb thigh muscle development pattern of frogs and their adaption to life history stages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07677-0.

Prenatal Skeletal Muscle Transcriptome Analysis Reveals Novel MicroRNA-mRNA Networks Associated with Intrauterine Growth Restriction in Pigs

Intrauterine growth restriction (IUGR) occurs in 15–20% of pig neonates and poses huge economic losses to the pig industry. IUGR piglets have reduced skeletal muscle growth, which may persist after birth. Prenatal muscle growth is regulated by complex molecular pathways that are not well understood. MicroRNAs (miRNAs) have emerged as the main regulators of vital pathways and biological processes in the body. This study was designed to identify miRNA–mRNA networks regulating prenatal skeletal muscle development in pigs. We performed an integrative miRNA–mRNA transcriptomic analysis in longissimus dorsi muscle from IUGR fetuses and appropriate for gestational age (AGA) fetuses at 63 days post conception. Our data showed that 47 miRNAs and 3257 mRNAs were significantly upregulated, and six miRNAs and 477 mRNAs were significantly downregulated in IUGR compared to AGA fetuses. Moreover, 47 upregulated miRNAs were negatively correlated and can potentially target 326 downregulated genes, whereas six downregulated miRNAs were negatively correlated and can potentially target 1291 upregulated genes. These miRNA–mRNA networks showed enrichment in biological processes and pathways critical for fetal growth, development, and metabolism. The miRNA–mRNA networks identified in this study can potentially serve as indicators of prenatal fetal growth and development as well as postnatal carcass quality.

Key Genes Regulating Skeletal Muscle Development and Growth in Farm Animals

Simple Summary

Skeletal muscle mass is an important economic trait, and muscle development and growth is a crucial factor to supply enough meat for human consumption. Thus, understanding (candidate) genes regulating skeletal muscle development is crucial for understanding molecular genetic regulation of muscle growth and can be benefit the meat industry toward the goal of increasing meat yields. During the past years, significant progress has been made for understanding these mechanisms, and thus, we decided to write a comprehensive review covering regulators and (candidate) genes crucial for muscle development and growth in farm animals. Detection of these genes and factors increases our understanding of muscle growth and development and is a great help for breeders to satisfy demands for meat production on a global scale.

Abstract

Farm-animal species play crucial roles in satisfying demands for meat on a global scale, and they are genetically being developed to enhance the efficiency of meat production. In particular, one of the important breeders’ aims is to increase skeletal muscle growth in farm animals. The enhancement of muscle development and growth is crucial to meet consumers’ demands regarding meat quality. Fetal skeletal muscle development involves myogenesis (with myoblast proliferation, differentiation, and fusion), fibrogenesis, and adipogenesis. Typically, myogenesis is regulated by a convoluted network of intrinsic and extrinsic factors monitored by myogenic regulatory factor genes in two or three phases, as well as genes that code for kinases. Marker-assisted selection relies on candidate genes related positively or negatively to muscle development and can be a strong supplement to classical selection strategies in farm animals. This comprehensive review covers important (candidate) genes that regulate muscle development and growth in farm animals (cattle, sheep, chicken, and pig). The identification of these genes is an important step toward the goal of increasing meat yields and improves meat quality.

MicroRNA expression profile in bovine mammary gland parenchyma infected by coagulase-positive or coagulase-negative staphylococci

MicroRNAs (miRNAs) are short, non-coding RNAs, 21-23 nucleotides in length which are known to regulate biological processes that greatly impact immune system activity. The aim of the study was to compare the miRNA expression in non-infected (H) mammary gland parenchyma samples with that of glands infected with coagulase-positive staphylococci (CoPS) or coagulase-negative staphylococci (CoNS) using next-generation sequencing. The miRNA profile of the parenchyma was found to change during mastitis, with its profile depending on the type of pathogen. Comparing the CoPS and H groups, 256 known and 260 potentially new miRNAs were identified, including 32 that were differentially expressed (p ≤ 0.05), of which 27 were upregulated and 5 downregulated. Comparing the CoNS and H groups, 242 known and 171 new unique miRNAs were identified: 10 were upregulated (p ≤ 0.05), and 2 downregulated (p ≤ 0.05). In addition, comparing CoPS with H and CoNS with H, 5 Kyoto Encyclopedia of Genes and Genomes pathways were identified; in both comparisons, differentially-expressed miRNAs were associated with the bacterial invasion of epithelial cells and focal adhesion pathways. Four gene ontology terms were identified in each comparison, with 2 being common to both immune system processes and signal transduction. Our results indicate that miRNAs, especially miR-99 and miR-182, play an essential role in the epigenetic regulation of a range of cellular processes, including immunological systems bacterial growth in dendritic cells and disease pathogenesis (miR-99), DNA repair and tumor progression (miR-182).

Skeletal Muscle Transcriptome Analysis of Hanzhong Ma Duck at Different Growth Stages Using RNA-Seq

As one of the most important poultry worldwide, ducks (Anas platyrhynchos) are raised mainly for meat and egg products, and muscle development in ducks is important for meat production. Therefore, an investigation of gene expression in duck skeletal muscle would significantly contribute to our understanding of muscle development. In this study, twenty-four cDNA libraries were constructed from breast and leg muscles of Hanzhong Ma ducks at day 17, 21, 27 of the embryo and postnatal at 6-month-old. High-throughput sequencing and bioinformatics were used to determine the abundances and characteristics of transcripts. A total of 632,172,628 (average 52,681,052) and 637,213,938 (average 53,101,162) reads were obtained from the sequencing data of breast and leg muscles, respectively. Over 71.63% and 77.36% of the reads could be mapped to the Anas platyrhynchos genome. In the skeletal muscle of Hanzhong duck, intron variant (INTRON), synonymous variant (SYNONYMOUS_CODING), and prime 3' UTR variant (UTR_3_PRIME) were the main single nucleotide polymorphisms (SNP) annotation information, and "INTRON", "UTR_3_PRIME", and downstream-gene variant (DOWNSTREAM) were the main insertion-deletion (InDel) annotation information. The predicted number of alternative splicing (AS) in all samples were mainly alternative 5' first exon (transcription start site)-the first exon splicing (TSS) and alternative 3' last exon (transcription terminal site)-the last exon splicing (TTS). Besides, there were 292 to 2801 annotated differentially expressed genes (DEGs) in breast muscle and 304 to 1950 annotated DEGs in leg muscle from different databases. It is worth noting that 75 DEGs in breast muscle and 49 DEGs in leg muscle were co-expressed at all developmental points of comparison, respectively. The RNA-Seq data were confirmed to be reliable by qPCR. The identified DEGs, such as CREBL2, RHEB, GDF6, SHISA2, MYLK2, ACTN3, RYR3, and STMN1, were specially highlighted, indicating their strong associations with muscle development in the Hanzhong Ma duck. KEGG pathway analysis suggested that regulation of actin cytoskeleton, oxidative phosphorylation, and focal adhesion were involved in the development of skeletal muscle. The findings from this study can contribute to future investigations of the growth and development mechanism in duck skeletal muscle.

Characterization of Autozygosity in Pigs in Three-Way Crossbreeding

Crossbreeding in livestock can be used to increase genetic diversity. The resulting increase in variability is related to the heterozygosity of the crossbred animal. The evolution of diversity during crossbreeding can be assessed using genomic data. The objective of this study was to describe patterns of runs of homozygosity (ROH) in animals resulting from three-way crossbreeding, from parental pure lines, and in their crossbred offspring. The crossbreeding scheme consisted of a first crossbreeding Pietrain boars and Large White sows, after which the offspring of the Pietrain × Large White were crossed with Duroc boars. The offspring of the second crossbreeding are called G0, the offspring of G0 boars and G0 sows are called G1. All the animals were genotyped using the Illumina SNP60 porcine chip. After filtering, analyses were performed with 2,336 animals and 48,579 autosomal single nucleotide polymorphism (SNP). The mean ROH-based inbreeding coefficients were shown to be 0.27 ± 0.05, 0.23 ± 0.04, and 0.26 ± 0.04 for Duroc, Large White, and Pietrain, respectively. ROH were detected in the Pietrain × Large White crossbred but the homozygous segments were fewer and smaller than in their parents. Similar results were obtained in the G0 crossbred. However, in the G1 crossbreds the number and the size of ROH were higher than in G0 parents. Similar ROH hotspots were detected on SSC1, SSC4, SSC7, SSC9, SSC13, SSC14, and SSC15 in both G0 and G1 animals. Long ROH (>16 Mb) were observed in G1 animals, suggesting regions with low recombination rates. The conservation of these homozygous segments in the three crossbred populations means that some haplotypes were shared between parental breeds. Gene annotation in ROH hotspots in G0 animals identified genes related to production traits including carcass composition and reproduction. These findings advance our understanding of how to manage genetic diversity in crossbred populations.

MicroRNA profiling of the pig periaqueductal grey (PAG) region reveals candidates potentially related to sex-dependent differences

Background

MicroRNAs indirectly orchestrate myriads of essential biological processes. A wide diversity of miRNAs of the neurodevelopmental importance characterizes the brain tissue, which, however, exhibits region-specific miRNA profile differences. One of the most conservative regions of the brain is periaqueductal grey (PAG) playing vital roles in significant functions of this organ, also those observed to be sex-influenced. The domestic pig is an important livestock species but is also believed to be an excellent human model. This is of particular importance for neurological research because of the similarity of pig and human brains as well as difficult access to human samples. However, the pig PAG profile has not been characterized so far. Moreover, molecular bases of sex differences connected with brain functioning, including miRNA expression profiles, have not been fully deciphered yet.

Methods

Thus, in this study, we applied next-generation sequencing to characterize pig PAG expressed microRNAs. Furthermore, we performed differential expression analysis between females and males to identify changes of the miRNA profile and reveal candidates underlying sex-related differences.

Results

As a result, known brain-enriched, and new miRNAs which will expand the available profile, were identified. The downstream analysis revealed 38 miRNAs being differentially expressed (DE) between female and male samples. Subsequent pathway analysis showed that they enrich processes vital for neuron growth and functioning, such as long-term depression and axon guidance. Among the identified sex-influenced miRNAs were also those associated with the PAG physiology and diseases related to this region.

Conclusions

The obtained results broaden the knowledge on the porcine PAG miRNAome, along with its dynamism reflected in different isomiR signatures. Moreover, they indicate possible mechanisms associated with sex-influenced differences mediated via miRNAs in the PAG functioning. They also provide candidate miRNAs for further research concerning, i.e., sex-related bases of physiological and pathological processes occurring in the nervous system.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-020-00343-2.

Identification of mRNA Degradome Variation Dependent on Divergent Muscle Mass in Different Pig Breeds

The search is still on for the molecular processes associated with the development and metabolism of skeletal muscles. Selection conducted in farm animals is focused on high muscle mass because it delivers higher economic profit. The present study aimed to shed light on mRNA degradome signals that could be characteristic for molecular processes associated with an abundance of muscle mass and to identify miRNA regulatory networks controlling these processes in pigs applying next-generation-sequencing (NGS). In the study, over 10,000 degraded transcripts were identified per sample, with the highest abundance for genes encoding mitochondrial proteins (COXs, NDs, CYTB, ATP6 and ATP8). Moreover, only 26% of the miRNA targets were found within this degraded transcript pool, which suggested for miRNAs other molecular mechanism at different level of gene expression than mRNA degradation. On the other hand, a small share of the identified degraded transcripts associated with miRNA regulation suggests a different mechanism of mRNA degradation for identified degraded transcropts. Subsequently, most of the miRNA gene degraded targets, such as ENO3, CKM, CRYAB and ADAM19 encode proteins involved in the muscle mass control. The present study showed an interesting dependence between miRNAs and their targets. Nevertheless, the complete view of the miRNA regulatory network could be a subject of further advanced research, which would employ a miRNA transfection procedure in skeletal muscle cell cultures.

Taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling

Gossypol, a toxic polyphenol extracted from cotton seeds, is hazardous to human and animal health. Taurine is considered as an essential or semi-essential amino acid and has diverse cytoprotective effects. This study was aimed to investigate the protective effect and molecular mechanism of taurine against apoptosis of C2C12 mouse myoblasts induced by gossypol. C2C12 mouse myoblasts were exposed to gossypol (0, 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM). Cell numbers were rapidly decreased with increasing concentrations of gossypol. Gossypol significantly induced apoptosis, decreased Bcl2 expression, and increased the protein levels of Bax and the cleaved caspase 3. Taurine (0.24 mM) treatment largely rescued the cell number decreased by gossypol, attenuated gossypol-induced cell apoptosis. GPR87 knockdown abolished the inhibition by taurine of cell apoptosis. Furthermore, GPR87 overexpression attenuated cell apoptosis induced by gossypol. Both taurine treatment and GPR87 overexpression stimulated AKT phosphorylation but inhibited AMPK phosphorylation, whereas gossypol had the opposite effects. Taurine treatment promoted GPR87 expression and subcellular localization and partially rescued the inhibition of gossypol on this expression. In summary, these data reveal that taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling.

miR-9-5p Inhibits Skeletal Muscle Satellite Cell Proliferation and Differentiation by Targeting IGF2BP3 through the IGF2-PI3K/Akt Signaling Pathway

MicroRNAs are evolutionarily conserved, small non-coding RNAs that play critical post-transcriptional regulatory roles in skeletal muscle development. We previously found that miR-9-5p is abundantly expressed in chicken skeletal muscle. Here, we demonstrate a new role for miR-9-5p as a myogenic microRNA that regulates skeletal muscle development. The overexpression of miR-9-5p significantly inhibited the proliferation and differentiation of skeletal muscle satellite cells (SMSCs), whereas miR-9-5p inhibition had the opposite effect. We show that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is a target gene of miR-9-5p, using dual-luciferase assays, RT-qPCR, and Western Blotting, and that it promotes proliferation and differentiation of SMSCs. In addition, we found that IGF2BP3 regulates IGF-2 expression, using overexpression and knockdown studies. We show that Akt is activated by IGF2BP3 and is essential for IGF2BP3-induced cell development. Together, our results indicate that miR-9-5p could regulate the proliferation and differentiation of myoblasts by targeting IGF2BP3 through IGF-2 and that this activity results in the activation of the PI3K/Akt signaling pathway in skeletal muscle cells.

Mammalian Annotation Database for improved annotation and functional classification of Omics datasets from less well-annotated organisms

Next-generation sequencing technologies and the availability of an increasing number of mammalian and other genomes allow gene expression studies, particularly RNA sequencing, in many non-model organisms. However, incomplete genome annotation and assignments of genes to functional annotation databases can lead to a substantial loss of information in downstream data analysis. To overcome this, we developed Mammalian Annotation Database tool (MAdb, https://madb.ethz.ch) to conveniently provide homologous gene information for selected mammalian species. The assignment between species is performed in three steps: (i) matching official gene symbols, (ii) using ortholog information contained in Ensembl Compara and (iii) pairwise BLAST comparisons of all transcripts. In addition, we developed a new tool (AnnOverlappeR) for the reliable assignment of the National Center for Biotechnology Information (NCBI) and Ensembl gene IDs. The gene lists translated to gene IDs of well-annotated species such as a human can be used for improved functional annotation with relevant tools based on Gene Ontology and molecular pathway information. We tested the MAdb on a published RNA-seq data set for the pig and showed clearly improved overrepresentation analysis results based on the assigned human homologous gene identifiers. Using the MAdb revealed a similar list of human homologous genes and functional annotation results regardless of whether starting with gene IDs from NCBI or Ensembl. The MAdb database is accessible via a web interface and a Galaxy application.

Sequential feeding with high-fat/low-crude protein diets for two lines of growing-finishing pigs under daily cyclic high ambient temperature conditions1

This study was conducted to evaluate the effects of sequential feeding technique in two genetic lines (GL; Line A [cross having a greater proportion of Pietrain] and Line B [cross having a lower proportion of Pietrain]) of growing-finishing pigs reared under daily cyclic high ambient temperature conditions. Seventy-eight castrated male pigs (22 ± 2.5 kg BW) were housed in a single group and were allocated to one of the three feeding programs: control (CON, 24 h control diet), high-fat/low-crude protein (HF/LP, 24 h high-fat/low-crude protein diet), and sequential feeding (SEQ, control diet from 1800 to 1000 h and HF/LP diet from 1001 to 1759 h). Cyclic high ambient temperature was induced by exposing the pigs to 22ºC ambient temperature from 1800 to 1000 h (time-period 22ºC, TP22) and to 30ºC from 1001 to 1759 h (TP30). The experimental period lasted 84 days and was divided into 3 growth phases, growing 1 (from day 0 to 20), growing 2 (from day 21 to 48) and finishing (from day 49 to 83). Feed intake was recorded in real time using an automatic feeder system. Pigs were weighed at the beginning and end of each experimental phase. Animal body composition was measured through dual-energy X-ray absorptiometry on days 0, 35, and 70. The ambient temperature averaged 22.3 ± 0.4ºC during TP22 and 30.2 ± 0.5ºC during TP30, characterizing the condition of daily ambient temperature variation that which pigs are usually exposed in tropical climate areas. During growing phase 1, the feeding programs had negligible effects on pig performance (P > 0.05), whereas during growing phase 2, ADG was greater in SEQ than in CON pigs (7%; P = 0.04). During the finishing phase, HF/LP pigs had greater ADFI (+ 10%) and ADG (+ 8%) than CON pigs. Lean mass and gain did not differ among feeding programs (P > 0.05). Overall, fat mass and gain were similar between SEQ and HF/LP pigs (P > 0.05), and both were greater than those of CON pigs (P < 0.05). On the basis of pig performance per phase, the supply of high-fat/low-crude protein diets (SEQ and HF/LP feeding) improved the performance of pigs under daily cyclic high ambient temperature. However, the use of these techniques resulted in fatter carcasses and in higher energy cost of gain. Finally, pigs with greater proportion of Pietrain genes had decreased growth performance in our experimental conditions.