The African catfish, Clarias gariepinus , is a commercially vital fish that is cultured worldwide, but it often exhibits low‐quality flesh despite high production, which limits its market value. Consequently, there is increasing interest in identifying alternative feed ingredients that can improve flesh quality without severely compromising growth performance. Previous studies have shown that the inclusion of raw faba beans (...

A new cyprinid gudgeon, Saurogobio rarus sp. nov., is described here based on morphological and molecular data. Morphologically, the new species resembles its congener S. dabryi the most, but with distinct differences. S. rarus sp. nov. has the naked area on chest restricted to or a little over the pectoral‐fin base, as opposed to extending much over the pectoral base or extending to posterior portion of the pectoral fin rays...

NOD‐like receptors (NLRs) serve as crucial innate immune sensors in multicellular organisms, recognizing diverse pathogen‐associated components and regulating immune responses such as nuclear factor kappa B (NF‐κB) signalling and inflammatory pathways. To elucidate the roles of NLRC3 , NLRC5 and NLRX1 in the innate immunity of the Mastacembelus armatus , this study first characterized these genes and examined their response to...

Faba bean ( Vicia faba L.) has garnered interest from the aquatic feed industry as a plant‐based ingredient that may enhance muscle hardness and crispness in tilapia. However, faba beans contain numerous anti‐nutritional factors (ANFs) that could affect animal growth and health through their metabolic products. Germination effectively reduces the content of ANFs in faba beans; however, the effects of germinated faba beans on t...

Gut microbiota stability is crucial for maintaining fish health. In aquaculture, antibiotics and disinfectants are frequently used to manipulate the host gut microbiota, but the combined effects on asymptomatic fish remain unclear. We investigated the effects of single and combined treatments with antibiotics and disinfectants on grass carp ( Ctenopharyngodon idella ) gut health, immune response, microbiome dynamics and transc...

The hemicultrine fishes are a group of small‐sized cyprinids, widely distributed but endemic to East Asian rivers and lakes. Till now, the taxonomic boundaries and relationships within this group remain poorly explored. In the present study, we study the phylogeny of this group, providing suggestions for classification of the hemicultrine group. Using two mitochondrial and three nuclear genes, and samples representing all gene...

To improve the accuracy and efficiency of fish behavior assessment, this paper focuses on quantitatively exploring the variations and relationships between different monitoring dimensions. A systematic comparison was conducted between 3D and 2D behavioral factors using an infrared tracing system, during both day and night. Significant differences in swimming distance were observed among the different monitoring methods, as det...

Conservation practices from the perspective of functional diversity (FD) and conservation prioritization need to account for the impacts of exotic species in freshwater ecosystems. This work first simulated the influence of exotic species on the values of FD in a schemed mechanistic model, and then a practical case study of conservation prioritization was performed in the Min River, the largest river in southeastern China, to...

Growth rate is a commercial trait in aquaculture that is influenced by multiple factors, among which genetic composition plays a fundamental role in the growth rate of species. The phoenix barb ( Spinibarbus denticulatus denticulatus ) is a widely distributed freshwater fish species in South China. Although S. d. denticulatus is reared in South China, the molecular mechanisms underlying the growth rate of the species remain un...

Sex change in teleost fishes is commonly regulated by social factors. In species that exhibit protogynous sex change, such as the orange‐spotted grouper Epinephelus coioides , when the dominant males are removed from the social group, the most dominant female initiates sex change. The aim of this study was to determine the regulatory mechanisms of socially controlled sex change in E. coioides . We investigated the seasonal var...

Sexual patterns of teleosts are extremely diverse and include both gonochorism and hermaphroditism. As a protogynous hermaphroditic fish, all orange‐spotted groupers ( Epinephelus coioides ) develop directly into females, and some individuals change sex to become functional males later in life. This study investigated gonadal restructuring, shifts in sex hormone levels and gene profiles of cultured mature female groupers durin...

A full‐length complementary (c)DNA sequence encoding follistatin‐related protein 3 ( fsrp‐3 ) was determined from skeletal muscle in Chinese mandarin fish Siniperca chuatsi , its molecular structure was characterised and its function suggested. The putative structure of S. chuatsi Fsrp‐3 contains an N‐terminal domain and two follistatin domains. Quantitative reverse‐transcription (qRT)‐PCR assays revealed that fsrp‐3 messenger...

Socially controlled sex change in teleosts is a dramatic example of adaptive reproductive plasticity. In many cases, the occurrence of sex change is triggered by a change in the social context, such as the disappearance of the dominant individual. The orange‐spotted grouper Epinephelus coioides is a typical protogynous hermaphrodite fish that changes sex from female to male and remains male throughout its life span. In this st...

This study tested whether eutrophication could influence life‐history traits of a cyprinid, Chanodichthys erythropterus , in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length ( L ∞ ) and the growth performance index ( I GRO ) were significantly affected by eutrophication. The gonado‐somatic index ( I G ) and relative fecundity ( F R ) were significantly lower in mesotrophic lakes than in eutrophic...

In this study, the full‐length neuropeptide Y ( npy ) complementary (c) DNA was cloned in ya fish Schizothorax prenanti . npy cDNA was composed of 789 nucleotides with a 288 nucleotide open reading frame encoding a protein of 96 amino acids. The deduced amino acid sequences contained a 28 amino acids signal peptide followed by a 36 amino acids mature neuropeptide Y (NPY). The npy mRNA was expressed mainly in the brain and eye...

In this study, the role of chicken gonadotropin‐releasing hormone II ( cgnrhII ) in feeding regulation was investigated in Schizothorax prenanti . First, the full‐length S. prenanti cgnrhII cDNA consisted of 693 bp with an open reading frame of 261 bp encoding a protein of 86 amino acids. Next, cgnrhII was widely expressed in the central and peripheral tissues. Last, there were significant changes in cgnrhII mRNA expression in...

In this study, the cDNA sequence encoding interleukin‐1 ( Il ‐1) receptor‐like protein of orange‐spotted grouper Epinephelus coioides was obtained. The newly identified sequence was named soluble type I Il ‐1 receptor ( sIl‐1rI ) owing to its structural composition, which had two Ig‐like domains, lack of transmembrane region and the Toll/interleukin‐1 receptor ( TIR ) domain, similar to the brown rat Rattus norvegicus soluble...

In this study, complementary DNA (cDNA) and DNA sequences of major histocompatibility complex (MHC) class IIB genes ( mhcIIB ) were cloned from orange‐spotted grouper Epinephelus coioides . The gene structure of E. coioides mhcIIB consists of five exons and four introns, and its deduced amino acid sequence length is 249 amino acids, including a signal peptide, a peptide‐binding region, an IGC1 domain, a transmembrane region an...

The morphology of gametes and the fertilization biology of Japanese flounder Paralichthys olivaceus (Po), summer flounder Paralichthys dentatus (Pd) and their hybrids were examined. Multiple generations (two hybrids: Po♀× Pd♂ (F1) and Pd♀× Po♂; two backcrosses: F1♀× Po♂ and F1♀× Pd♂) were obtained by artificial insemination. Comparison of egg ultrastructure among Po, Pd and F1 showed the morphology of micropyle region and the...

To understand the molecular mechanisms associated with digestive physiology of the stomach of orange‐spotted grouper Epinephelus coioides , a cDNA library was constructed and 331 expressed sequence tags (EST) were generated and annotated. About 37·17% of 226 identified ESTs were possibly related to digestive enzymes. Two type‐A pepsinogens differing in putative isoelectric point were identified and characterized for the first...