Fish & Shellfish Immunology

Infection-induced hemolysis results in intravascular hemolysis, which releases hemoglobin (Hb) into the tissues. Free Hb exhibits cytotoxic, oxidative, and pro-inflammatory effects, leading to systemic inflammation, vascular constriction dysfunction, thrombosis, and proliferative vascular lesions. Currently, the impact of intravascular hemolysis on the middle kidney in fish is unclear. Here, the injection of phenylhydrazine (PHZ) was used to establish a persistent hemolysis model in grass carp. The determination results revealed that the PHZ-induced hemolysis caused conspicuous tissue damage in the kidneys of grass carp, increased the levels of Cr in the serum and the expression indicators of kidney injury-related genes in the middle kidney...

Crucian carp (Carassius carassius) is an important aquatic economic animal, and the immune barrier function of its intestine has been a focus of research into oral vaccines and drugs. However, the histological structures of the intestinal barrier and its adjacent areas have not been clearly established, and little subcellular evidence is available to elucidate the spatial distribution of intracellular biological processes. In this study, the spatial distribution of autophagy and endosome formation in the intestinal epithelial cells (IECs) of crucian carp were analyzed...

Alternative splicing serves as a pivotal source of complexity in the transcriptome and proteome, selectively connecting various coding elements to generate a diverse array of mRNAs. This process encodes multiple proteins with either similar or distinct functions, contributing significantly to the intricacies of cellular processes. The role of alternative splicing in mammalian immunity has been well studied. Remarkably, the immune system of fish shares substantial similarities with that of humans, and alternative splicing also emerges as a key player in the immune processes of fish...

Excess utilization of plant protein sources in animal feed has been found to adversely affect the antioxidant properties and immunity of animals. While the role of gut microbes in plant protein-induced inflammation has been identified in various models, the specific mechanisms regulating gut microbes in crustaceans remain unclear. Accordingly, this study was designed to investigate the effects of replacing fishmeal with soybean meal (SM) on the hepatopancreas antioxidant and immune capacities, and gut microbial functions of crayfish, as well as the potential microbial regulatory mechanisms...

Copper/zinc superoxide dismutase (Cu/Zn-SOD) can effectively eliminate reactive oxygen species (ROS)，avoid damage from O2 to the body, and maintain O2 balance. In this study, multi-step high-performance liquid chromatography (HPLC), combined with Mass Spectrometry (MS), was used to isolate and identify Cu/Zn-SOD from the serum of Pinctada fucata martensii (P. f. martensii) and was designated as PmECSOD. With a length of 1864 bp and an open reading frame (ORF) of 1422 bp, the cDNA encodes a 473 amino acid protein...

Non-specific cytotoxic cells (NCCs) are vital immune cells involved in teleost's non-specific immunity. As a receptor molecule on the NCCs' surface, the non-specific cytotoxic cell receptor protein 1 (NCCRP-1) is known to play a crucial role in mediating their activity. Nevertheless, there have been limited studies on the signal molecule that transmits signals via NCCRP-1. In this study, a yeast two-hybrid (Y2H) library of tilapia liver and head kidney was constructed and subsequently screened with the bait vector NCCRP-1 of Oreochromis niloticus (On-NCCRP-1) to obtain a C-type lectin (On-CTL) with an interacting protein sequence...

In mammals, IL-22 is considered as a critical cytokine regulating of immunity and homeostasis at barrier surfaces. Although IL-22 have been functional characterization in different species of fish, the studies about distinct responses of IL-22 in different organs/tissues/cell types is rather limited. Here, we identified and cloned IL-22 gene (named as Ec-IL-22) from grouper (Epinephelus coioides). Ec-IL-22 gene was detected in all orangs/tissues examined, and was induced in intestine, gill, spleen, head kidney, and primary head kidney/intestine leukocytes following the stimulation of LPS and poly(I:C), as well as Vibrio harveyi and Singapore grouper iridovirus infection (SGIV)...

A type of fermented bile acids (FBAs) has been produced through a biological method, and its effects on growth performance, metabolism, and intestinal microbiota in largemouth bass were investigated. The results demonstrated that incorporating 0.03% to 0.05% FBAs diet could improve the final weight, weight gain and specific growth rate, and decrease the feed conversion ratio. Dietary FBAs did not significantly affect the levels of high-density lipoprotein, low-density lipoprotein, and triglycerides, but decreased the activities of α-amylase in most groups...

This study investigated the effects of fish protein hydrolysate derived from barramundi on growth performance, muscle composition, immune response, disease resistance, histology and gene expression in white shrimp (Penaeus vannamei). In vitro studies demonstrated FPH enhanced mRNA expressions of key immune-related genes and stimulated reactive oxygen species (ROS) production and phagocytic activity in shrimp hemocytes. To evaluate the effects of substituting fish meal with FPH in vivo, four isoproteic (43%), isolipidic (6%), and isoenergetic diets (489 kcal/100g) were formulated with fish meal substitution levels of 0% (control), 30% (FPH30), 65% (FPH65), and 100% (FPH100)...

This study aimed to elucidate the effects of dietary fermented products of Bacillus velezensis T23 on the growth, immune response and gut microbiota in Pacific white shrimp (Litopenaeus vannamei). Shrimp were fed with diets containing fermentation products of B. velezensis T23 at levels of (0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 g/kg) for 4 weeks, to assess the influence on shrimp growth. The results showed that 0.3 and 0.4 g/kg T23 supplementation improved shrimp growth and feed utilization. Based on these results we selected these three diets (Control, 0...

Streptococcosis, the most common bacterial disease of fish in recent years, is highly infectious and lethal, and has become an important factor hindering the healthy and sustainable development of aquaculture. Chicken egg yolk antibody (IgY) has the advantages of high antigen specificity, inexpensive and easy to obtain, simple preparation, no toxic side effects, and in line with animal welfare, which is a green and safe alternative to antibiotics. In this study, the potential of specific IgY in the treatment of gastrointestinal pathogens was explored by observing the effects of specific IgY on intestinal flora, pathological tissue, apoptosis, oxidative stress, and inflammatory response of tilapia...

B-cell lymphoma/leukemia-2 (BCL2), an anti-apoptotic factor in the mitochondrial regulatory pathway of apoptosis, is critically important in immune defenses. In this study, a novel BCL2 gene was characterized from Pteria penguin (P. penguin). The PpBCL2 was 1482 bp long, containing an open reading frame (ORF) of 588 bp encoding 195 amino acids. Four highly conserved BCL-2 homology (BH) domains were found in PpBCL2. Amino acid alignment and phylogenetic tree showed that PpBCL2 had the highest similarity with BCL2 of Crassostrea gigas at 65...

Members of the Signal Transducer and Activator of Transcription (STAT) family function pivotally as transcriptional activators integral to the modulation of inflammatory responses. The aquaculture of silver pomfret is frequently compromised by the imposition of exogenous stressors, which include thermal fluctuations, notably low-temperatures, diminished oxygen levels, and the onslaught of bacterial pathogens. Notwithstanding the critical impact of these stressors, the scientific literature presents a notable gap in our understanding of the STAT pathway's role in the silver pomfret's adaptive response mechanisms...

Akirin2 is pivotal for regulating host immunological responses in vertebrates, including antibacterial immunity and inflammation. However, the functional significance of Akirin2 in invertebrates remains largely unexplored. In this study, we cloned the complete cDNA sequence of Akirin2 from A. japonicus (AjAkirin2) and elucidated its immunological mechanism upon pathogen infection. The whole AjAkirin2 cDNA sequence spanned 1014 bp, which comprised a 630 bp open reading frame encoding 209 amino acids, a 230 bp 5'-untranslated region (UTR), and a 154 bp 3'-UTR...

Toll-like receptors (TLRs) are one of the extensively studied pattern recognition receptors (PRRs) and play crucial roles in the immune responses of vertebrates and invertebrates. In this study, 14 TLR genes were identified from the genome-wide data of Octopus sinensis. Protein structural domain analysis showed that most TLR proteins had three main structural domains: extracellular leucine-rich repeats (LRR), transmembrane structural domains, and intracellular Toll/IL-1 receptor domain (TIR). The results of subcellular localization prediction showed that the TLRs of O...

Vibrio harveyi causes high mortality and severely limits grouper culture. The gut microbiota is an important biological barrier against pathogen invasion. In this study, we investigated dynamic changes in the intestinal microbial community, gene transcription and immune responses signatures of pearl gentian grouper (Epinephelus fuscoguttatus♂ × Epinephelus lanceolatus♀) at 0, 3 and 7 days (referred to as d0, d3 and d7 groups, respectively) after infection with V. harveyi. The results demonstrated that the d7 treatment reduced the gut microbial diversity and increased the proportion of Proteobacteria and Cyanobacteria...

In aquaculture, fluctuating water temperatures can act as a potent stressor, influencing the virulence and transmission dynamics of pathogenic bacteria, potentially triggering outbreaks and impacting fish health. The purpose of this work was to examine the impact of Shewanella spp. infection on hematological, biochemical, and antioxidant-immune parameters of Nile tilapia (Oreochromis niloticus) under different water temperatures. For this purpose, 180 fish were divided into 6 groups in triplicate (30 fish per group; 10 fish per replicate)...

The copepod Lernathropus kroyeri constitutes one of the major parasites for the Mediterranean aquaculture, infesting the sea bass Dicentrarchus labrax causing thus disruptions of growth performance and occasionally mortalities. Despite the large spread and the high frequency of this parasite in mariculture farms of Eastern Mediterranean, L. kroyeri genetic profile from aquaculture as well as the pathophysiological response of D. labrax have not been studied so far. Keeping this in mind, in the present study we investigated the L...

MicroRNAs are increasingly recognized for their pivotal role in the immune system, yet the specific regulatory functions of fish-derived microRNAs remain largely unexplored. In this research, we discovered a novel miRNA, Cse-miR-144, in the Chinese tongue sole (Cynoglossus semilaevis), characterized by a 73-base pair precursor and a 21-nucleotide mature sequence. Our findings revealed that the expression of Cse-miR-144 was notably inhibited by various Vibrio species. Utilizing bioinformatics and dual-luciferase assay techniques, we established that the pro-inflammatory cytokine gene CsMAPK6 is a direct target of Cse-miR-144...

Deubiquitinating enzyme A (DUBA), a member of the ovarian tumor (OTU) subfamily of deubiquitinases (DUBs), is recognized for its negative regulatory role in type I interferon (IFN) expression downstream of Toll-like receptor 3 (TLR3). However, its involvement in the TLR3 signaling pathway in fish remains largely unexplored. In this study, we investigated the regulatory role of DUBA (OmDUBA) in the TLR3 response in rainbow trout (Oncorhynchus mykiss). OmDUBA features a conserved OTU domain, and its expression increased in RTH-149 cells following stimulation with the TLR3 agonist poly(I:C)...