Aquaculture Reports最新文献

{"title":"Selenium-enriched Lacticaseibacillus paracasei enhances growth performance, antioxidant capacity, and gut health in Micropterus salmoides","authors":"Jiacong Deng ,&nbsp;Zhihong Chen ,&nbsp;Xu Chen ,&nbsp;Xiangzhu Shi ,&nbsp;Jinlin Fan ,&nbsp;Xucong Lv ,&nbsp;Yinggu Kuang","doi":"10.1016/j.aqrep.2026.103452","DOIUrl":"10.1016/j.aqrep.2026.103452","url":null,"abstract":"<div><div>This study establishes <em>Lacticaseibacillus paracasei</em> ACCC10639 as a selenium-enriched probiotic through dual-phase optimization for <em>Micropterus salmoides</em> aquaculture. Strain selection under gradient sodium selenite stress (4–64 mg/L) revealed 32 mg/L Na₂SeO₃ as the optimal production concentration, achieving 13.78 mg/g organic selenium (59.8 % organic speciation) while maintaining 70 % biomass viability. Subsequent dose-response trials identified 2.0 g/kg as the optimal dietary supplementation level through multi-parameter evaluation of growth performance, antioxidant capacity, and microbiota modulation. At this dual-optimized regimen (32 mg/<span>L</span>-manufactured biomass and 2.0 g/kg feed dose), the selenized probiotic induced systemic improvements versus non-selenized controls: 12.7 % higher specific growth rate (3.89 vs 3.45 %/d), 18.6 % lower feed conversion ratio (1.40 vs 1.72), and 70 % enhanced glutathione peroxidase activity (79.4 vs 46.8 U/mgprot). Hepatic lipid peroxidation was 29 % reduced (MDA 1.06 vs 1.50 nmol/mgprot), accompanied by 15.2 % decreased hepatosomatic index. Ecological analysis using weighted UniFrac distances revealed tight microbiota clustering (NMDS stress=0.02) and distinct community separation via Principal Coordinate Analysis (72.9 % variation along PC1) in the SeLp group, with Firmicutes dominance at 89.8 % (+9.4 points) and butyrate production peaking at 182 % control levels. Pathogen suppression reached 97.6 % (<em>Aeromonas</em>) and 99.7 % (<em>Vibrio</em>). Spearman correlations revealed <em>Lactobacillus</em> abundance strongly associated with growth (ρ=0.92) and oxidative stress mitigation (ρ=-0.94), while butyrate emerged as a key antioxidant mediator (ρ=-0.94 with MDA). These findings validate selenium probiotic optimization through strain-specific production (32 mg/L) and dose-dependent application (2.0 g/kg), providing a sustainable strategy to replace inorganic selenium in carnivorous aquaculture.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103452"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First insight into the insemination-induced spawning method in pikeperch (Sander lucioperca) without the presence of a male","authors":"Ádám Varga ,&nbsp;Balázs Kucska ,&nbsp;József Horváth ,&nbsp;Nguyễn Ngọc Quyến ,&nbsp;Tamás Szabó ,&nbsp;Uroš Ljubobratović ,&nbsp;Türker Bodur ,&nbsp;Hüseyin Sevgili ,&nbsp;Hajime Matsubara ,&nbsp;Tamás Müller","doi":"10.1016/j.aqrep.2026.103421","DOIUrl":"10.1016/j.aqrep.2026.103421","url":null,"abstract":"<div><div>The insemination-based propagation method, in which sperm is inseminated and stored in the ovary until ovulation, may offer a unique approach to induced spawning in externally fertilizing, nest-spawning fish species. This study evaluated the effectiveness and limitations of this technique in pikeperch (<em>Sander lucioperca</em>) propagation under artificial conditions in the absence of males. In the experiment, ten female pikeperch were hormonally induced with carp pituitary extract and inseminated via catheter. Oocyte maturation was monitored by serial biopsies, and spawning was facilitated using artificial substrates. Results showed that eight out of ten experimental females ovulated spontaneously, but exhibited considerable variation in the timing of egg release (83–100 h post-hormone administration). Fertilisation rates ranged widely (0–83.9 %), with no clear correlation to the latency time of sperm in the ovary. The absence of males led to atypical egg dispersion and could have contributed to inadequate ovulation success as well. While insemination-induced spawning can enable reproduction without males and may increase genetic diversity by using multiple sperm samples, its efficiency is constrained by species-specific sperm viability and the absence of natural spawning behavior. Further optimisation is necessary for broader application in pikeperch aquaculture.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103421"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The serotonin receptor 5-HTR modulates larval settlement and metamorphosis in Manila clam Ruditapes philippinarum","authors":"Hongsu Yang ,&nbsp;Lei Zhang ,&nbsp;Biao Wu ,&nbsp;Zhihong Liu ,&nbsp;Liqing Zhou ,&nbsp;Peizhen Ma ,&nbsp;Zhuanzhuan Li ,&nbsp;Xiujun Sun","doi":"10.1016/j.aqrep.2026.103445","DOIUrl":"10.1016/j.aqrep.2026.103445","url":null,"abstract":"<div><div>The Manila clam (<em>Ruditapes philippinarum</em>), as one of the most economically significant shellfish species in China, faces major challenges in seed production due to the high mortality during larval settlement and metamorphosis. 5-Hydroxytryptamine (5-HT) has been identified as a crucial neurotransmitter involved in regulating larval settlement and metamorphosis in molluscs. However, the underlying signaling mechanisms of its receptor (5-HTR) in molluscs remain poorly understood. In this study, the full-length cDNA sequence of 5-HT1R gene (1343 bp) is successfully cloned, encoding a protein of 393 amino acids. Bioinformatics analysis results reveal that the encoded protein has the typical characteristics of G protein-coupled receptors, including seven transmembrane domains and a molecular weight of 45.61 kDa. Quantitative real-time PCR (qPCR) results show that 5-HT1R expression in gill tissue of adult clams is significantly higher than that in other tissues, followed by adductor muscle and foot tissues. Whole-mount <em>in situ</em> hybridization illustrates its dynamic expression pattern throughout larval development, especially during larval settlement and metamorphosis. Prior to larval settlement and metamorphosis, 5-HT1R is predominantly localized in the apical sensory organ (ASO) of the larva, while the positive signals are progressively diminished during metamorphosis and eventually disappear after metamorphosis. Moreover, chemical induction experiments of larval settlement and metamorphosis using 5-HT agonists and antagonists have proved that 1 μM 5-HT treatment significantly enhances larval settlement and metamorphosis (60.9 %), whereas antagonists (clozapine) markedly suppress this process. These evidences indicate that 5-HT1R exerts the crucial regulatory function during larval settlement and metamorphosis of <em>R. philippinarum</em>. This study not only provides a theoretical foundation for elucidating the molecular mechanism underlying larval settlement and metamorphosis, but also offers potential targets for further investigation of 5-HT signaling pathway in bivalves.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103445"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developing standard production diets for early juvenile Diadema antillarum sea urchins","authors":"Casey G. Hudspeth ,&nbsp;Aaron R. Pilnick ,&nbsp;Alex Petrosino ,&nbsp;Jessica N. Smith ,&nbsp;Joshua T. Patterson","doi":"10.1016/j.aqrep.2026.103430","DOIUrl":"10.1016/j.aqrep.2026.103430","url":null,"abstract":"<div><div>High post-settlement mortality represents a major bottleneck in sea urchin aquaculture. Better understanding of diet requirements during this early juvenile stage and the development of novel feeding protocols offers potential to advance culture outcomes. Here we describe a series of experiments investigating dietary effects on early juvenile growth and survival of an ecologically important species <em>Diadema antillarum,</em> the long-spined sea urchin. Due to a die-off event in the 1980s, natural populations of this keystone reef herbivore are exceedingly low; closed-life cycle aquaculture can potentially supplement wild populations with captive-reared individuals. Current standard-practice methods utilize naturally-derived biofilms as a first-feeding diet. However, inconsistent composition and surface colonization can lead to unpredictable yields from one cohort to the next. To address this limitation, two replicated experiments initiated at different timepoints post-metamorphosis compared effects of the following diet treatments on growth and survival: naturally biofilmed glass tiles, a benthic diatom <em>Navicula perminuta</em>, flocculated live planktonic microalgae <em>Rhodomonas salina</em> and <em>Chaetoceros muelleri</em>, and a non-feeding treatment. Significant differences were noted among treatments in both experiments. Throughout the first three weeks post-settlement, juveniles in the treatment fed <em>N. perminuta</em> grew larger than those in the natural biofilm treatment. Flocculated microalgae then resulted in higher growth than biofilm throughout weeks 4–7 post-metamorphosis. Survival was consistent across treatments, except in the non-feeding treatment. These findings expand understanding of dietary needs during this delicate life stage. Further, recommendations are provided for applying these methods to other ecologically and commercially relevant sea urchin species.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103430"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing tilapia robustness: Moringa essential oil improves growth, gut morphology, innate immunity, antioxidant capacity, and ammonia tolerance in Nile tilapia","authors":"Amr I. Zaineldin ,&nbsp;Safaa E. Abdo ,&nbsp;Gehan I.E. Ali ,&nbsp;Aly S. Saif ,&nbsp;Mohammed Rashed ,&nbsp;Walid S. Abdo ,&nbsp;Ehab Elsebaey ,&nbsp;Mahmoud A.O. dawood","doi":"10.1016/j.aqrep.2026.103428","DOIUrl":"10.1016/j.aqrep.2026.103428","url":null,"abstract":"<div><div>This study investigated Moringa oleifera essential oil (MEO) as a functional feed additive for Nile tilapia (<em>Oreochromis niloticus</em>), focusing on ammonia stress mitigation. A 56-day trial allocated 300 fish into five groups (0 %, 0.5 %, 1 %, 1.5 %, or 2 % MEO supplementation). Results demonstrated that MEO significantly enhanced growth performance, increasing final body weight, weight gain, specific growth rate, feed intake, feed efficiency, and protein efficiency ratio, while reducing the feed conversion ratio (FCR). Optimal inclusion levels were 1.3–1.4 % for growth. Furthermore, histological examination demonstrated that MEO supplementation significantly improved intestinal morphology, characterized by increased villus height, enhanced goblet cell density, and greater villous branching complexity compared to control groups. The MEO-supplemented groups exhibited significantly higher immun<em>e response</em>, evidenced by elevated innate immune responses (lysozyme activity, IgM levels, phagocytosis). Concurrently, antioxidant capacity improved through upregulated activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT), elevated total serum protein, coupled with a reduction in malondialdehyde (MDA). Furthermore<em>,</em> the oligopeptide transporter (<em>PepT1</em>), <em>M</em>ucin (<em>Muc</em>), Insulin like growth factor (<em>IGF-1</em>), Growth hormone <em>receptor</em> (<em>GHR1</em>), <em>G</em>lutathione peroxidase (<em>GPx</em>), Catalase (<em>CAT</em>), <em>L</em>ysozyme (<em>LYZ</em>), Complement (<em>C3</em>) genes expression significantly increased in MEO supplemented groups. Following ammonia challenge, Moringa oleifera essential oil (MEO) supplementation significantly enhanced ammonia tolerance in Nile tilapia (<em>Oreochromis niloticus</em>), as evidenced by prolonged LT50 values, while simultaneously suppressing stress responses through reduced plasma cortisol and glucose levels. Collectively, our findings indicate that dietary MEO inclusion improves growth performance while positively modulating physiological status through three key mechanisms: enhanced immune function, strengthened antioxidant defenses, and effective prevention of ammonia stress-induced physiological disruptions. This positions MEO as a multifunctional feed additive for sustainable tilapia aquaculture under challenging environmental conditions.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103428"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of amino acid chelate micronutrients on physiology and intestinal flora of Litopenaeus vannamei fed with cottonseed protein concentrate (CPC) replacement of fishmeal in diet","authors":"Xianglong Song ,&nbsp;Chao Li ,&nbsp;Beiping Tan ,&nbsp;Xiaohui Dong ,&nbsp;Qihui Yang ,&nbsp;Shuyan Chi ,&nbsp;Shuang Zhang ,&nbsp;Shiwei Xie ,&nbsp;Hongyu Liu","doi":"10.1016/j.aqrep.2026.103451","DOIUrl":"10.1016/j.aqrep.2026.103451","url":null,"abstract":"<div><div>Concentrated cottonseed protein (CPC) serves as an ideal protein replacement for fish meal in diets, though excessive use can adversely affect aquatic life. Organic trace element replacements can sustain the growth and metabolic functions of <em>Litopenaeus vannamei</em>, aiding in the conservation of high-quality protein resources such as fish meal. The purpose of this experiment is to explore the impact of substituting fish meal with CPC as a protein source, along with substituting amino acid trace element chelates, on the growth, immune antioxidant capacity, and intestinal microbiota of <em>Litopenaeus vannamei</em>. Four experimental diets were formulated: the control group FM (no CPC substitution, supplemented with inorganic trace elements), the inorganic trace element group C0 (CPC substituted for 40 % fish meal, supplemented with inorganic trace elements), and the experimental group C1 (CPC substituted for 40 % fish meal, amino acid trace element chelates substituted for 40 % inorganic trace elements). and C2 (CPC replacing 40 % fish meal, amino acid chelated trace minerals replacing 60 % inorganic trace minerals). Each group had three replicates. At the end of a 10-week feeding trial, the research results are as follows: Group C2 had significantly higher crude protein and crude lipid contents compared to Group C0 (<em>P</em> &lt; 0.05). In comparison to Group C0, the FM group demonstrated much higher activities of CuZn-SOD, GPX, and CAT (<em>P</em> &lt; 0.01), group C0 exhibited notably lower activities compared to Groups C1 and C2 (<em>P</em> &lt; 0.05). Relative abundances of major intestinal microbiota species in Groups C1 and C2 underwent significant changes. Compared to Groups C0 and C2, the expression levels of lipid metabolism genes were much higher in Group C1 (<em>P</em> &lt; 0.05). In fish meal replacement diets with CPC, using 40 % amino acid chelates can mitigate adverse effects of plant protein and enhance shrimp lipid metabolism, immune antioxidants, and intestinal flora.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103451"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoperiod modulates ontogenetic opsin expression in the endangered salmonid Brachymystax tsinlingensis during early development","authors":"Xing-chen Guo ,&nbsp;Shi-hui Huang ,&nbsp;Zhen-lu Wang ,&nbsp;Yi-zhou Wang ,&nbsp;Zhi-peng Chu ,&nbsp;Zhuo Liu ,&nbsp;Huan Ye ,&nbsp;Dong-mei Xiong ,&nbsp;Yu Li ,&nbsp;Miao An ,&nbsp;Jian Shao","doi":"10.1016/j.aqrep.2026.103435","DOIUrl":"10.1016/j.aqrep.2026.103435","url":null,"abstract":"<div><div>Photoperiod orchestrates key developmental events in salmonids, like smoltification. The endangered, light-sensitive <em>Brachymystax tsinlingensis</em> faces a juvenile production bottleneck, possibly mediated by visual opsins. To optimize light conditions from an opsin plasticity perspective, we quantified ontogenetic expression of all five visual opsins (<em>RH1</em>, <em>RH2</em>, <em>SWS1</em>, <em>SWS2</em>, <em>LWS</em>) from embryos to juveniles (59 days) under six photoperiods. Results revealed distinct, photoperiod-sensitive expression patterns: <em>RH1</em>, <em>SWS2</em>, and <em>LWS</em> expression was delayed, and opsin dynamics varied significantly across treatments. Despite this, all opsins increased throughout development regardless of photoperiod, with <em>RH1</em>, <em>SWS1</em>, and <em>LWS</em> being most abundant, indicating a strong genetic component. This demonstrates precise illumination requirements for early development. Rearing under complete darkness or natural-like cycles supports full opsin repertoire development, aiding conservation of this endangered species.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103435"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of various dietary levels of carbohydrate/lipid ratios on growth and health status of juvenile Ussuri catfish (Pseudobagrus ussuriensis)","authors":"Yichen Bai ,&nbsp;Xuqiu Lian ,&nbsp;Peizhong Yu ,&nbsp;Jiawei Dong ,&nbsp;Zhiyuan Xue ,&nbsp;Peng Liu ,&nbsp;Yuhong Yang","doi":"10.1016/j.aqrep.2026.103415","DOIUrl":"10.1016/j.aqrep.2026.103415","url":null,"abstract":"<div><div>To investigate the effects of dietary carbohydrate/lipid (CHO: L) ratios on the growth performance, nonspecific immune responses, oxidative status, and disease resistance of Ussuri catfish (<em>Pseudobagrus ussuriensis</em>), and to determine the optimal dietary CHO: L ratio, we designed six isonitrogenous and isocaloric diets (with carbohydrate-lipid ratios ranging from 0.89 to 7.02) for an 8-week feeding trail on <em>Pseudobagrus ussuriensis</em>. The results showed that the WG and SGR first increased and then decreased, reaching the highest values when the CHO:L ratio was 2.02. Meanwhile, the plasma LZM activity, complement 3 level, and respiratory burst activity reached their maximum values. In addition, when the CHO:L ratio was 2.02, the SOD activity, CAT activity, and TAC in the fish liver reached the highest values, and the MDA level decreased as the CHO:L ratio increased from 0.89 to 2.02 and then leveled off. Moreover, as the CHO:L ratio increased from 0.89 to 7.02, the mRNA levels of <em>TNF-α</em>, <em>IL-1β</em>, and <em>HSP70</em> all showed a trend of first decreasing and then increasing and reached their lowest values when the CHO:L ratio was 2.02. In contrast, the mRNA expression level of <em>IL-10</em> in the fish liver first increased and then decreased, reaching the highest value when the CHO:L ratio was 2.02. It is worth noting that when the CHO:L ratio exceeds 2.02, the mortality rate of fish after infection with <em>Aeromonas hydrophila</em> increases, and the mortality rate reaches the highest when the CHO:L ratio is 7.02. To sum up, based on various physiological indicators, the feed with a CHO:L ratio of 2.02 is most suitable for the needs of juvenile <em>Pseudobagrus ussuriensis</em>. This finding provides a reliable reference for the precise nutritional requirement of juvenile <em>Pseudobagrus ussuriensis</em>., which has certain reference value for actual aquaculture production.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103415"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrolysate of a low-carbon microbe protein improved the performance and antioxidant capacity in Micropterus salmoides","authors":"Shiyou Chen ,&nbsp;Xiaofang Liang ,&nbsp;Jie Wang ,&nbsp;Hao Wang ,&nbsp;Yaping Zhu ,&nbsp;Chongyang Li ,&nbsp;Shifeng Ma ,&nbsp;Junjun Wang ,&nbsp;Min Xue","doi":"10.1016/j.aqrep.2026.103429","DOIUrl":"10.1016/j.aqrep.2026.103429","url":null,"abstract":"<div><div>Low-fishmeal diets (LFM) represent a promising strategy for sustainable aquaculture, yet their practical efficacy remains inconsistent. <em>Clostridium autoethanogenum</em> protein hydrolysate (CAPH), derived from a low-carbon microbial protein with potential physiological regulatory functions, was evaluated in this study. We investigated graded CAPH supplementation (1.5 % and 3 %) in an LFM diet (24 % fishmeal) for largemouth bass, using a high-fishmeal control diet (HFM, 30 % fishmeal) as the benchmark. Results indicated that the LFM group achieved growth performance and physiological indices comparable to the HFM, confirming baseline adaptability to reduced fishmeal content. Notably, dietary 1.5 % CAPH significantly improved growth, while decreasing the feed conversion ratio. Further analysis revealed that CAPH improved intestinal morphological characteristics and enhanced the activity of intestinal digestive enzymes (alkaline phosphatase, trypsin, and amylase). CAPH addition upregulated the mRNA level of genes related to intestinal peptide transport (<em>pept1</em> and <em>pept2</em>) and amino acid transport (<em>lat1</em>, <em>lat2</em>, <em>sant2</em>, and <em>sant4</em>), corresponding with increased plasma amino acid concentrations. Additionally, CAPH (1.5 %) activated hepatic mTOR signaling, evidenced by elevated mRNA level of <em>mtor</em>, alongside reduced <em>4e-bp1</em> gene expression. CAPH enhances antioxidant responses by reducing reactive oxygen species (ROS) and increasing total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity. Accordingly, the activated hepatic Nrf2-keap1 signaling were observed in CAPH groups. These findings demonstrate that dietary fishmeal reduction from 30 % to 24 % maintained comparable growth performance in largemouth bass. In comparison, CAPH supplementation optimally enhances growth performance, feed utilization, and antioxidant capacity through coordinated regulation of digestive function, peptide/amino acid transport, Nrf2-keap1, and mTOR pathways.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103429"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution and diversity of antibiotic resistance genes and bacterial communities in aquaculture systems in Guangdong, China","authors":"Quanfa Zhong ,&nbsp;Weihao Li ,&nbsp;Zhibing Chen ,&nbsp;Zhifei Li ,&nbsp;Yun Xia ,&nbsp;Kai Zhang ,&nbsp;Jingjing Tian ,&nbsp;Hongyan Li ,&nbsp;Wenping Xie ,&nbsp;Guangjun Wang ,&nbsp;Jun Xie ,&nbsp;Wangbao Gong","doi":"10.1016/j.aqrep.2026.103433","DOIUrl":"10.1016/j.aqrep.2026.103433","url":null,"abstract":"<div><div>Antibiotics are increasingly used and released into the environment due to the rapid development of aquaculture, resulting in spread of antibiotic resistance. This study investigated the distribution and diversity of antibiotic resistance genes (ARGs) in the aquaculture waterbody of different aquaculture systems in Guangdong, as well as their associations with opportunistic pathogens. A comparative analysis of 92 samples revealed that selected ARGs were more prevalent in freshwater aquaculture systems (FAS) than in marine aquaculture systems (MAS), with higher accumulation levels of tetracycline (Tet) and sulfonamide (Sul) resistance genes observed in FAS. Notably, certain ARGs such as <em>tetG_F</em> and <em>mphA</em> were more abundant in MAS compared to FAS, suggesting differing antibiotic selection pressures across the two systems. Analysis of bacterial communities revealed distinct compositions: FAS was dominated by <em>Acidobacteria</em> and <em>Chloroflexi</em>, while <em>Actinobacteria</em> and <em>Bacteroidetes</em> were more prevalent in MAS. Network analysis showed positive correlations between opportunistic pathogens and selected ARGs, suggesting that these pathogens may serve as reservoirs for resistance genes and pose potential public health risks. Bacterial community assembly in MAS was primarily driven by stochastic processes, whereas both deterministic and stochastic processes influenced community structure in FAS. Moreover, TN, NH₄⁺ , NO₂^-, and PO₄^3- strongly influence bacterial communities and ARGs, with greater effects in MAS. Overall, this study reveals the complex interactions among microbial diversity, ARGs, and environmental factors, providing a theoretical foundation for mitigating the spread of antibiotic resistance in aquaculture and improving ecosystem health.</div></div>","PeriodicalId":8103,"journal":{"name":"Aquaculture Reports","volume":"47 ","pages":"Article 103433"},"PeriodicalIF":3.7,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}