Comparison of LC-PUFAs Biosynthetic Characteristics in Male and Female Tilapia at Different Ontogenetic Stages.

Tilapia possess the ability to biosynthesize long-chain polyunsaturated fatty acids (LC-PUFA); however, variations in this capacity across different growth stages and between sexes remain poorly understood. This study evaluated the LC-PUFA biosynthetic capacity in male and female tilapia fed two distinct diets-perilla oil (rich in α-linolenic acid, ALA) and peanut oil (rich in linoleic acid, LA)-over 24 weeks, spanning four growth stages (I-IV, from fry to adult). The results revealed that during stages I to III, both diets produced similar final body weights.

Synergistic Regulation of Pigment Cell Precursors' Differentiation and Migration by and in Nile Tilapia.

The evolutionary loss of in specific vertebrate lineages, such as mammals and cypriniform fish, raises fundamental questions about its functional necessity and potential redundancy or synergy with paralogous endothelin receptors in pigment cell development. In teleosts possessing both and (e.g.

Creation of colorless transparent tilapia using CRISPR/Cas9 mediated multi-gene mutation.

Transparent mutant fish have been obtained from small-sized fish (medaka, zebrafish, and killifish), and are often used as experimental models in biological and medical research. However, transparent fish have never been created in medium- or large-sized fish through gene editing. In this study, mutants without xanthophores, erythrophores and pigmented melanophores were first obtained by crossing to form tyrb;csf1ra double mutant tilapia.

Dual cyp17a1/a2 knockout unveils paralog-specific steroid pathways in fish reproduction.

Cyp17a is a key enzyme in steroidogenesis and reproduction in vertebrates. In teleosts, two paralogous genes, cyp17a1 and cyp17a2, have been identified, and while the potential impact of mutations in these genes have been studied, a comprehensive comparative analysis of their regulatory mechanisms in teleost reproduction remains lacking. In this study, we established a double mutant (dko) of cyp17a1 and cyp17a2 and conducted a transcriptome analysis of their gonads to systematically investigate the differences in steroidogenesis and gene expression between the two genes.

Prepubertal exposure to 17β-estradiol downregulates motor protein genes, impairs sperm flagella formation, and reduces fertility in Nile tilapia (Oreochromis niloticus).

Studies have demonstrated that adult male fish exposed to estrogenic endocrine-disrupting compounds (EDCs) exhibit reduced sperm motility and fertility. However, the effects of prepubertal estrogenic EDC exposure on testicular development and subsequent reproductive capacity remain poorly understood. In this study, prepubertal male (XY) tilapia at 30 days after hatching (dah) were exposed to 17β-estradiol (E2) for 60 days, covering the prepubertal period, to investigate its impact on testicular development and fertility at sexual maturity.

A novel modified peptide derived from tilapia piscidin 4 with improved cytotoxicity, stability and antibacterial activity against fish pathogens and its underlying antibacterial mechanism.

Tilapia piscidin 4 (TP4) is an amphiphilic cationic antimicrobial peptide derived from Nile tilapia (Oreochromis niloticus), known for its broad-spectrum antimicrobial activity, potent anti-tumor effects, and immunomodulatory property. However, its significant toxicity and poor stability pose major challenges for practical applications. In this study, the TP4 sequence was modified by deleting nine amino acids from the N-terminal region and substituting glycine at the 13th position with cysteine, resulting in a modified peptide designated TP4-16G4C (FSACKAIHRLIRRRRR).

Carotenoids, instead of pteridines, determine color of xanthophores and erythrophores in tilapia.

There has been controversy over whether the chromogenic substances of xanthophores and erythrophores are pteridines or carotenoids in fish. In this study, we first extracted and quantified carotenoids and pteridines from erythrophores and xanthophores in tilapia, respectively. The results showed that the carotenoids and pteridines in erythrophores were significantly higher than those of xanthophores, and the carotenoids were significantly higher than the pteridines in both types of cells.

The origin, evolution, and translocation of sex chromosomes in Silurus catfish mediated by transposons.

Background: Sex chromosome (SC) evolution is a longstanding topic of focus in evolutionary biology. Teleosts often exhibit rapid turnover of SCs and sex-determining (SD) genes, alongside a diverse range of SC differentiation mechanisms.

Results: On the basis of new chromosome-scale assemblies of three Silurus species (S.

Transcriptome-derived evidence reveals the regulatory network in the skeletal muscle of the fast-growth mstnb male tilapia.

Myostatin (Mstn) negatively regulates muscle growth and Mstn deficiency induced "double-skeletal muscle" development in vertebrates, including tilapias. In this study, we performed a transcriptomic analysis of skeletal muscle from both wild-type and mstnb males to investigate the molecular mechanisms underlying skeletal muscle hypertrophy in mstnb mutants. We identified 4697 differentially expressed genes (DEGs), 113 differentially expressed long non-coding RNAs (DE lncRNAs), 211 differentially expressed circular RNAs (DE circRNAs), and 98 differentially expressed microRNAs (DE miRNAs).

Investigating the molecular mechanisms of oocyte maturation and ovulation in Nile tilapia: A focus on the steroidogenic enzyme Cyp17a2.

Previous research has highlighted the significant role of progestins and glucocorticoids in fish oocyte maturation and ovulation. To clarify the molecular mechanisms underlying these processes, comprehensive investigations were conducted using a mutant Nile tilapia ( ) model. Analysis revealed pronounced Cyp17a2 expression in ovarian somatic cells of the tilapia.

Is Responsible for Androgen-Induced Masculinization in Nile Tilapia.

17α-Methyltestosterone (MT) is a widely used androgen for all-male fish production in aquaculture. However, the molecular mechanism underlying MT-induced masculinization remains unclear. In this study, we aim to identify the key gene responsible for MT-induced masculinization using the Nile tilapia () , , and mutants, which exhibit male-to-female sex reversal.

Steroid hormone-deprived sex reversal in cyp11a1 mutant XX tilapia experiences an ovary-like stage at molecular level.

Fish sex is largely influenced by steroid hormones, especially sex hormones. Here, we established a steroid hormone-free genetic model by mutation of cyp11a1 in Nile tilapia, which was confirmed by EIA assay. Gonadal phenotype and transcriptome analyses showed that the XX mutants displayed sex reversal from female to male but with defective spermatogenesis.

Sex chromosome turnover and biodiversity in fishes.

The impact of sex chromosomes and their turnover in speciation remains a subject of ongoing debate in the field of evolutionary biology. Fishes are the largest group of vertebrates, and they exhibit unparalleled sexual plasticity, as well as diverse sex-determining (SD) genes, sex chromosomes, and sex-determination mechanisms. This diversity is hypothesized to be associated with the frequent turnover of sex chromosomes in fishes.

Mutation of mpv17 results in loss of iridophores due to mitochondrial dysfunction in tilapia.

Mpv17 (mitochondrial inner membrane protein MPV17) deficiency causes severe mitochondrial DNA depletion syndrome in mammals and loss of pigmentation of iridophores and a significant decrease of melanophores in zebrafish. The reasons for this are still unclear. In this study, we established an mpv17 homozygous mutant line in Nile tilapia.

Hypogonadotropic hypogonadism in male tilapia lacking a functional rln3b gene.

Relaxin 3 is a neuropeptide that plays a crucial role in reproductive functions of mammals. Previous studies have confirmed that rln3a plays an important role in the male reproduction of tilapia. To further understand the significance of its paralogous gene rln3b in male fertility, we generated a homozygous mutant line of rln3b in Nile tilapia.

Star1 gene mutation reveals the essentiality of 11-ketotestosterone and glucocorticoids for male fertility in Nile Tilapia (Oreochromis niloticus).

Steroidogenic acute regulatory protein (Star) plays an essential role in the biosynthesis of corticosteroids and sex steroids by mediating the transport of cholesterol from the outer to the inner membrane of mitochondria. Two duplicated Star genes, namely star1 and star2, have been identified in non-mammalian vertebrates. To investigate the roles of star genes in fish steriodogenesis, we generated two mutation lines of star1 and star1/star2 in Nile tilapia (Oreochromis niloticus).

The cellular expression patterns of gdnfa and gdnfb in the gonads of Nile tilapia and their differential response to retinoic acid.

In mammals, glial cell derived neurotrophic factor (GDNF) plays a critical role in the self-renewal and maintenance of spermatogonial stem cells (SSCs) in testis and oogenesis in ovary, whilst retinoic acid (RA), the key factor of meiosis initiation, can downregulate its expression. Unlike mammals, two Gdnf replication genes are widely present in teleost fishes, however, our understanding of them is still poor. In the present study, two paralogous gdnf from Nile tilapia (Oreochromis niloticus), namely as Ongdnfa and Ongdnfb, were characterized, and then their cellular expression profiles in testis and ovary and responsiveness to RA treatment at the tissue and cellular levels were investigated.

Genome-wide analysis of two different regions of brain reveals the molecular changes of fertility related genes in rln3a mutants in male Nile tilapia (Oreochromis niloticus).

Relaxin3 (rln3) has been associated with various emotional and cognitive processes, including stress, anxiety, learning, memory, motivational behavior, and circadian rhythm. Notably, previous report revealed that Rln3a played an indispensable role in testicular development and male fertility in Nile tilapia (Oreochromis niloticus). However, the underlying molecular mechanisms remain largely unknown.

Nile Tilapia () Mutations Disrupt Cardiovascular Development and Vascular Integrity through Smoothened Signaling.

Hedgehog (Hh) signaling is crucial in cardiovascular development and maintenance. However, the biological role of Patched1 (Ptch1), an inhibitory receptor of the Hh signaling pathway, remains elusive. In this study, a Ptch1 ortholog was characterized in Nile tilapia (), and its function was investigated through CRISPR/Cas9 gene knockout.

Dmrt1 is the only male pathway gene tested indispensable for sex determination and functional testis development in tilapia.

Sex is determined by multiple factors derived from somatic and germ cells in vertebrates. We have identified amhy, dmrt1, gsdf as male and foxl2, foxl3, cyp19a1a as female sex determination pathway genes in Nile tilapia. However, the relationship among these genes is largely unclear.

Disruption of Zar1 leads to arrested oogenesis by regulating polyadenylation via Cpeb1 in tilapia (Oreochromis niloticus).

Oogenesis is a complex process regulated by precise coordination of multiple factors, including maternal genes. Zygote arrest 1 (zar1) has been identified as an ovary-specific maternal gene that is vital for oocyte-to-embryo transition and oogenesis in mouse and zebrafish. However, its function in other species remains to be elucidated.

Smoothened mediates medaka spermatogonia proliferation via Gli1-Rgcc-Cdk1 axis†.

The proliferation of spermatogonia directly affects spermatogenesis and male fertility, but its underlying molecular mechanisms are poorly understood. In this study, Smoothened (Smo), the central transducer of Hedgehog signaling pathway, was characterized in medaka (Oryzias latipes), and its role and underlying mechanisms in the proliferation of spermatogonia were investigated. Smo was highly expressed in spermatogonia.

Characterization of the male-specific region containing the candidate sex-determining gene in Amur catfish (Silurus asotus) using third-generation- and pool-sequencing data.

Amur catfish (Silurus asotus) is an ecologically and economically important fish species in Asia. Here, we assembled the female and male Amur catfish genomes, with genome sizes of 757.15 and 755.