Browsing by Author "Canario, Adelino"
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- 11-ketotestosterone inhibits the alternative mating tactic in sneaker males of the peacock blenny, Salaria pavoPublication . Oliveira, R. F.; Carneiro, L. A.; Gonçalves, D.; Canario, Adelino; Grober, M. S.In the peacock blenny, Salaria pavo, a species with courtship sex-role reversal, smaller, younger males mimic the courtship behavior and the nuptial coloration of females in order to get access to nests during spawning and to parasitize egg fertilization from nest-holder males. Later in their life, sneakers transform both morphologically and behaviorally into nest-holder males. In the present paper we investigate the activational role of 11-ketotestosterone (KT), the most potent androgen in most teleost species, to promote the switch between tactics in sneaker males of S. pavo. Sneakers were implanted either with KT or with control (i.e. castor oil) silastic implants. A week after implantation they were subjected to a set of behavioral tests and morphometric measurements. KT treatment promoted the differentiation of secondary sex characters, such as the anal glands, and inhibited the expression of female courtship behavior. KT-treated sneakers also showed a trend toward less frequent display of female nuptial coloration. There was no effect of KT treatment on the expression of typical nest-holder male behavior. Finally, there was no effect of KT treatment on the number or soma size of arginine vasotocin neurons in the preoptic area, which are often associated with the expression of vertebrate sexual behavior. Thus, KT seems to play a key role in mating tactic switching by inhibiting the expression of female courtship behavior and by promoting the development of male displaying traits (e.g. anal glands). The lack of a KT effect on behavior typical of nest-holding males and vasotocinergic preoptic neurons suggests that a longer time frame or other endocrine/social signals are needed for the initiation of these traits in males that are switching tactics.
- Bacterial 16S ribosomal gene fingerprints as a tool to diagnose and mitigate fish larvae gut dysbiosisPublication . NAJAFPOUR, BABAK; Canario, Adelino; Power, Deborah MaryDysbiosis is associated with shifts in the diversity or relative abundance of beneficial versus harmful bacteria, leading to health issues in organisms. This study investigated gut bacterial dysbiosis associated with larval quality using 16S rRNA gene sequencing. The gut microbiome of gilthead sea bream and European sea bass, key commercial species and vertebrate models, was examined in high- and low-quality larvae batches from several European hatcheries. Larval quality, hatchery site and species influenced bacterial diversity in the gut. Individuals from larval batches that performed well had higher microbial diversity in the gut and individuals from batches that performed poorly had a gut microbiota dominated by pathogenic Vibrio (e.g., V. aestuarianus and V. cortegadensis). The bacterial dysbiosis index revealed a notable predominance of Fusobacteriota and Firmicutes phyla, Thermoanaerobacteria class and Lactobacillaceae, Moritellaceae, Clostridiaceae, Thiotrichaceae and Shewanellaceae families in good-quality larvae batches, and a prevalence of the Proteobacteria phylum, Gammaproteobacteria class, Sphingomonadaceae and Vibrionaceae families in the gut of individuals from poor-quality larvae batches. A positive dysbiosis index (cutoff >0.4) was associated with a high risk of decreased larval performance and quality. Additionally, the abundance of Clostridium_sensu_ stricto_15, Shewanellaceae_unclassified, Cetobacterium, Psychrilyobacter, Moritella and Latilactobacillus genera in the gut of good production batches, and the Vibrio genus in the gut of poor production batches, identified these genus as potential markers for diagnosing and mitigating bacterial dysbiosis in fish and potentially other vertebrates.
- Behavioural responses to visual and chemical cues in Mozambique tilapia (Oreochromis mossambicus): a putative pheromonal activity for 17β-estradiol 3-glucuronatePublication . Ashoori, Samyar; Canario, Adelino; Hubbard, PeterIn reproduction of Mozambique tilapia (Oreochromis mossambicus), chemical communication mainly relies on urinary steroidal glucuronides (sex pheromones) that dominant males release to prime the final ovulation in pre-ovulatory females and increase reproductive readiness. However, the role of steroids in chemical communication in females has received less attention. Here, we aimed to determine whether 17 beta-estradiol 3-glucuronate released by pre-ovulatory females functions as a reproductive signal towards males. We investigated the preference of focal males to visual, chemical (female conditioned water), and a combination of both stimuli from pre-ovulatory or post-spawning females, as well as 10- 9 M 17 beta-estradiol 3-glucuronate. Compared to the control zone, where no stimuli were present, males were more responsive (time spent near the stimuli, digging behaviour, and urination frequency) in the visual and visual + chemical zones than in the chemical-only zone. Males preferred pre-ovulatory to post-spawning female-conditioned water. Interestingly, the time spent by focal males near the source of 17 beta-estradiol 3-glucuronate was similar to pre-ovulatory conditioned water. However, there was no significant difference in digging and urine pulses in response to 17 beta-estradiol 3-glucuronate compared to the control group. We suggest that male tilapia recognise the ovulation status of females using visual and chemical cues, and 17 beta-estradiol 3-glucuronate is part of the odorant content released by pre-ovulatory females to communicate their reproductive status.
- Bile acids as putative social signals in Mozambique tilapia (Oreochromis mossambicus)Publication . Ashouri, Samyar; Da Silva, José Paulo; Canario, Adelino; Hubbard, PeterChemical cues provide potential mates with information about reproductive status and resource-holding potential. In the Mozambique tilapia (Oreochromis mossambicus), males can distinguish female reproductive status through chemical cues, and accessibility of males to females depends on their position in the hierarchy, determined in part by chemical cues. Here, we hypothesized that tilapia faecal cues are attractive to conspecifics once released into the water. C18 solid-phase extracts of faeces from dominant males and pre-ovulatory females evoked stronger olfactory epithelium electrical responses (EOG) than, respectively, subordinate males and postspawning females. Mass spectrometry of the reverse-phase C18 high-performance liquid chromatography fractions of these extracts with highest EOG, identified by amino acids and bile acids. Faeces from pre-ovulatory females contain significantly higher concentrations of cholic acid (CA) and taurocholic acid (TCH) than both post-spawning females and males. A pool of amino acids had no effect on aggression or attraction in males. However, males were attracted to the scent of pre-ovulatory female faeces, as well as CA and TCH, when applied separately. This attraction was accompanied by increased digging behaviour compared to the odour of postspawning females. CA and TCH exert their action through separate receptor mechanisms. These findings are consistent with a role for faeces - and bile acids therein - in chemical communication in this species, acting as an attractant for males to reproductive females.
- Characterization and refinement of growth related quantitative trait loci in European sea bass (Dicentrarchus labrax) using a comparative approachPublication . Louro, Bruno; Kuhl, Heiner; Tine, Mbaye; de Koning, Dirk-Jan; Batargias, Costas; Volckaert, Filip A. M.; Reinhardt, Richard; Canario, Adelino; Power, DeborahThe identification of genetic markers for traits of interest for aquaculture, such as growth, is an important step for the establishment of breeding programmes. As more genomic information becomes available the possibility of applying comparative genomics to identify and refine quantitative trait locus (QTLs) and potentially identify candidate genes responsible for the QTL effect may accelerate genetic improvement in established and new aquaculture species. Here we report such an approach on growth related traits in the European sea bass (Dicentrarchus labrax), an important species for European aquaculture. A genetic map was generated with markers targeted to previously identified QTL for growth which reduced distance and improved resolution in these regions. A total of 36 significant QTLs were identified when morphometric traits were considered individually in maternal half sibs, paternal half sibs and sib-pair analysis. Twenty seven new markers targeted to the growth QTLs, obtained by comparative mapping, reduced the average distance between markers from 23.4, 9.1, and 5.8 cM in the previous map to 3.4, 2.2, and 5.2 cM, on linkage group (LG) LG4, LG6 and LG15 respectively. Lists of genes embedded in the QTL - 591 genes in LG4, 234 genes in LG6 and 450 genes in LG15 - were obtained from the European sea bass genome. Comparative mapping revealed conserved gene synteny across teleost fishes. Functional protein association network analysis with the gene products of the 3 linkage groups revealed a large global association network including 42 gene products. Strikingly the association network was populated with genes of known biological importance for growth and body weight in terrestrial farm animals, such as elements of the signaling pathways for Jak-STAT, MAPK, adipocytokine and insulin, growth hormone, IGFI and II. This study demonstrates the feasibility of a comparative genomics combined with functional gene annotation to refine the resolution of QTL and the establishment of hypothesis to accelerate discovery of putative responsible genes.Statement of relevance: This study demonstrates the feasibility of a comparative genomics approach, combined with functional annotation to refine the resolution of QTL and establishment of hypothesis to accelerate discovery of candidate genes. As production of genomic data is becoming more accessible, the implementation of this strategy will rapidly and efficiently provide the tools required for genetic selection in new candidate aquaculture species. (C) 2016 Elsevier B.V. All rights reserved.
- Chemical diplomacy in male tilapia: urinary signal increases sex hormone and decreases aggressionPublication . Saraiva, João; Keller-Costa, Tina; Hubbard, Peter; Rato, Ana; Canario, AdelinoAndrogens, namely 11-ketotestosterone (11KT), have a central role in male fish reproductive physiology and are thought to be involved in both aggression and social signalling. Aggressive encounters occur frequently in social species, and fights may cause energy depletion, injury and loss of social status. Signalling for social dominance and fighting ability in an agonistic context can minimize these costs. Here, we test the hypothesis of a 'chemical diplomacy' mechanism through urinary signals that avoids aggression and evokes an androgen response in receiver males of Mozambique tilapia (Oreochromis mossambicus). We show a decoupling between aggression and the androgen response; males fighting their mirror image experience an unresolved interaction and a severe drop in urinary 11KT. However, if concurrently exposed to dominant male urine, aggression drops but urinary 11KT levels remain high. Furthermore, 11KT increases in males exposed to dominant male urine in the absence of a visual stimulus. The use of a urinary signal to lower aggression may be an adaptive mechanism to resolve disputes and avoid the costs of fighting. As dominance is linked to nest building and mating with females, the 11KT response of subordinate males suggests chemical eavesdropping, possibly in preparation for parasitic fertilizations.
- Chromosome-level genome assembly of largemouth bass (Micropterus salmoides) using PacBio and Hi-C technologiesPublication . He, Kuo; Zhao, Liulan; Yuan, Zihao; Canario, Adelino; Liu, Qiao; Chen, Siyi; Guo, Jiazhong; Luo, Wei; Yan, Haoxiao; Zhang, Dongmei; Li, Lisen; Yang, SongThe largemouth bass (Micropterus salmoides) has become a cosmopolitan species due to its widespread introduction as game or domesticated fish. Here a high-quality chromosome-level reference genome of M. salmoides was produced by combining Illumina paired-end sequencing, PacBio single molecule sequencing technique (SMRT) and High-through chromosome conformation capture (Hi-C) technologies. Ultimately, the genome was assembled into 844.88 Mb with a contig N50 of 15.68 Mb and scaffold N50 length of 35.77 Mb. About 99.9% assembly genome sequences (844.00 Mb) could be anchored to 23 chromosomes, and 98.03% assembly genome sequences could be ordered and directed. The genome contained 38.19% repeat sequences and 2693 noncoding RNAs. A total of 26,370 protein-coding genes from 3415 gene families were predicted, of which 97.69% were functionally annotated. The high-quality genome assembly will be a fundamental resource to study and understand how M. salmoides adapt to novel and changing environments around the world, and also be expected to contribute to the genetic breeding and other research.
- Circannual prevalence of tetrodotoxins in trumpet shells: sea stars as a possible source of contamination and Implications for food safetyPublication . Pais, Maria; Carvalho, Flávia; Frade, Magda; Reis Costa, Pedro; Silva, José Paulo da; Marçalo, Ana; Canario, Adelino; Lage, SandraTetrodotoxin (TTX) is a potent neurotoxin, first identified in fish from the Tetraodontidae family but also detected in marine invertebrates. A Human poisoning episode after consumption of trumpet shell Charonia lampas, likely caught off the Portuguese mainland southern coast - Algarve, together with the increasing reports of TTX in European waters, led the European Food Safety Authority (EFSA) to recommend maximum safe limits for Human consumption of shellfish meat. However, data on temporal and species incidence of TTX are lacking. In the present study, TTX and its analogues were analysed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) in trumpet shells and in one of their potential prey sources of TTX, the sea star Astropecten aranciacus. The estimated toxicity, based on a Toxicity Equivalency Factors approach, of non-edible trumpet shell tissues consistently surpassed EFSA limits (44 mu g TTX equivalent (eq.) kg(-1)) over the studied year. A correlation between TTX concentration and bottom seawater temperature suggests a possible role of this parameter in TTX uptake. TTX levels in edible trumpet shell tissues and all but one sea star individual were below quantification limits. However, several TTX analogues were quantified in the sea stars, resulting in estimated toxicities (monthly averages) ranging from 7 to 64 mu g TTX eq kg(-1) in the digestive glands and from 0.3 to 27 mu g TTX eq. kg(-1) in the stomachs. Therefore, the sea star is a possible TTX source for trumpet shells. Despite the absence of TTX in common edible parts of trumpet shells, whole-shell sales in markets pose a consumer risk, highlighting the need for TTX monitoring and public awareness programs to prevent poisoning.
- Climate change impacts on fish reproduction are mediated at multiple levels of the brain-pituitary-gonad axisPublication . Servili, A.; Canario, Adelino; Mouchel, O.; Muñoz-Cueto, J.A.Anthropogenic emissions of carbon dioxide in the atmosphere have generated rapid variations in atmospheric composition which drives major climate changes. Climate change related effects include changes in physicochemical proprieties of sea and freshwater, such as variations in water temperature, salinity, pH/pCO(2) and oxygen content, which can impact fish critical physiological functions including reproduction. In this context, the main aim of the present review is to discuss how climate change related effects (variation in water temperature and salinity, increases in duration and frequency of hypoxia events, water acidification) would impact reproduction by affecting the neuroendocrine axis (brain-pituitary-gonad axis). Variations in temperature and photoperiod regimes are known to strongly affect sex differentiation and the timing and phenology of spawning period in several fish species. Temperature mainly acts at the level of gonad by interfering with steroidogenesis, (notably on gonadal aromatase activity) and gametogenesis. Temperature is also directly involved in the quality of released gametes and embryos development. Changes in salinity or water acidification are especially associated with reduction of sperm quality and reproductive output. Hypoxia events are able to interact with gonad steroidogenesis by acting on the steroids precursor cholesterol availability or directly on aromatase action, with an impact on the quality of gametes and reproductive success. Climate change related effects on water parameters likely influence also the reproductive behavior of fish. Although the precise mechanisms underlying the regulation of these effects are not always understood, in this review we discuss different hypothesis and propose future research perspectives.
- Comparative ontogeny of the digestive tract of Oncorhynchus mykiss female x Salmo trutta caspius male triploid hybrids to their parental speciesPublication . Najafpour, Babak; Dorafshan, Salar; Paykan Heyrati, Fatemeh; Canario, Adelino; Power, Deborahthe ontogeny of the gastrointestinal tract of the hybrid between female rainbow trout, RT (Oncorhynchus mykiss) and male Caspian brown trout, CBT (Salmo trutta caspius) was compared to the parental species. Larvae were collected for histology and enzymatic assays (amylase, lipase and trypsin) at 3, 6, 9, 12, 15, 18, 21, 26, 31, 35, 40 and 45 days post-hatch (dph). the development of the gastrointestinal tract (GI-tract) and the onset of digestive enzyme production was variable between groups. the GI-tract post-hatch was a relatively simple tubular structure, and a rudimentary oesophagus was differentiated from other regions at 3 dph in all studied groups. the pyloric caeca and the U-shaped stomach were clearly visible at 26, 35 and 40 dph in RT, triploid hybrid and CBT, respectively. An abrupt increase in trypsin activity at 31, 35 and 45 dph was identified in CBT, RT and the triploid hybrid, respectively. the increasing activity of trypsin and decreasing activity of lipase during larval development suggests that the CBT, RT and triploid hybrid rely more on dietary proteins than lipids with increasing age. the hybrid grew better and had a faster GI-tract development than CBT, while RT performed best overall.