The tub gurnard, Chelidonichthys lucerna, is considered the most important commercial fish species of the family Triglidae captured by the Portuguese traditional fisheries. However, the data available about its population structure, movement patterns and habitat connectivity is, at present, scarce. In this study, otolith chemistry and shape analyses of 90 individuals captured, between March and June 2016, in the three main fishing grounds of the Portuguese mainland coast (Matosinhos, Aveiro and Peniche) were investigated. Otolith morphological (shape indices and elliptic Fourier descriptors) and elemental (Ba:Ca, Fe:Ca, Mg:Ca, Mn:Ca, Sr:Ca and Zn:Ca) signatures of individuals with similar length range were assessed through uni and multivariate statistical tests. The overall combination of otolith elemental chemistry and morphology techniques revealed the highest re-classification success (74%) of samples to their original location and the existence of significant differences among sampling regions. However, linear discrimination function analyses and canonical analyses of principal coordinates did not fully discriminate C. lucerna individuals from the three sampling regions of Portugal. Moreover, the hereby data revealed a partial overlap among individuals from the different sampling regions. The obtained shape and chemical signatures suggest that C. lucerna is apparently a unique, although not necessarily homogenous, single population-unit in Portugal mainland, and that these fish populations should not be managed separately for fisheries purposes.

Brown trout is an environmental freshwater sentinel species and is economically important for recreational fishing and aquaculture. Despite that, there is limited knowledge regarding morpho-physiological variations in adults throughout the reproductive cycle. Thus, this study aimed to analyze the fitness and gonadal maturation of cultured adult brown trout in four reproductive phases (spawning capable—December, regressing—March, regenerating—July, and developing—November). The systematic evaluation of males and females was based on biometric, biochemical, and hormonal parameters, along with a histomorphological grading of gonads and the immunophenotype location of key steroidogenic enzymes. The total weight and lengths reached the lowest levels in December. Gonad weights were higher in December and November, while the opposite pattern was found for liver weights. The lowest levels of cholesterol and total protein were also noted during those stages. The 11-ketotestosterone (11-KT) and testosterone (T) for males, and estradiol (E2) and T for females, mostly explained the hormonal variations. The immunohistochemistry of cytochrome P450c17 (CYP17-I), aromatase (CYP19), and 17β-hydroxysteroid dehydrogenase (17β-HSD) showed sex and site-specific patterns in the distinct reproductive phases. The sex- and season-specific changes generated discriminative multi-parameter profiles, serving as a tool for environmental and aquaculture surveys.

The brown trout (Salmo trutta) is a commercially and ecologically significant salmonid fish, yet its hepatic cellular and functional dynamics throughout the reproductive cycle remain poorly characterised, particularly in males. This study investigated seasonal and sex-specific liver plasticity across four reproductive stages: spawning capable (December), regressing (March), regenerating (July), and developing (November). We quantified mRNA and protein abundance of key oestrogen-responsive targets—vitellogenin (VtgA) and zona pellucida (ZP) proteins—alongside cell turnover markers, caspase 3 (Casp3) and proliferating cell nuclear antigen (PCNA). These molecular endpoints were integrated with stereological analyses to estimate hepatocyte, nuclear, and cytoplasmic volumes. Results revealed stage-dependent mobilisation and transient hepatic retention of reproductive proteins; females exhibited stronger vitellogenic signatures and more pronounced seasonal shifts than males. Although VtgA and ZP mRNA levels peaked during the developing and spawning-capable stages, males maintained low but consistent levels throughout the cycle, indicating constitutive hepatic oestrogen sensitivity. Regarding cell turnover, PCNA protein data indicated heightened proliferative activity during the spawning-capable and regressing stages. In contrast, while Casp3 mRNA levels remained stable across all stages, protein detection suggested a post-transcriptional increase in apoptotic signalling during the developing phase, consistent with controlled tissue remodelling rather than extensive cell loss. Stereological data confirmed enlarged hepatocyte and nuclear volumes during periods of high secretory and proliferative demand. Overall, these findings demonstrate significant stage-dependent and sex-specific plasticity in brown trout liver, providing a robust reference framework for ecological monitoring, endocrine disruption assessments, and studies of teleost reproductive physiology.

Introdução: A síndrome de Wernicke-Korsakoff (SWK) é uma das mais graves consequências do abuso de álcool. O impacto cognitivo da patologia é derivado da neurotoxicidade alcóolica e deficiência de tiamina, podendo progredir para estupor, coma e morte. Objetivo: Realizar um estudo de caso de paciente alcoolista portador de SWK e construir um plano de assistência de enfermagem. Métodos: Estudo de caso com abordagem qualitativa. O estudo foi realizado no Hospital Universitário Oswaldo Cruz (HUOC), em Recife, Brasil, fevereiro a março de 2016. Resultados: Identificamos 14 diagnósticos de enfermagem: confusão crônica/memória prejudicada/processos do pensamento perturbados/ comunicação verbal prejudicada; deambulação prejudicada/risco de quedas; déficit no autocuidado; nutrição desequilibrada menor que as necessidades/fadiga; volume excessivo de líquido/integridade tissular prejudicada; risco de sangramento; integridade da pele prejudicada; perfusão tissular ineficaz. Conclusão: A enfermagem tem especial importância na execução das ações de educação em saúde e tratamento de alcoolistas prevenindo as complicações da doença.

Fatty acids are energy sources, and their profiles are used as biomarkers of metabolic status and physiological changes in fish. Within this context, the main aim of this study was to identify the fatty acids that best discriminate the reproductive status of male and female farmed brown trout. The fatty acid composition in liver and plasma samples from the adults of both sexes was monitored along four distinct reproductive stages, namely the spawning capable (December), regressing (March), regenerating (July), and developing (November) stages. Irrespective of the sex and stage, the most representative fatty acids were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1 n-9), arachidonic acid (20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3), and docosahexaenoic acid (DHA, 22:6 n-3). There were no significant sex differences in fatty acid classes in the liver and plasma. Despite this, there were several changes in individual fatty acid levels between the sexes. In the liver, both males and females showed high monounsaturated fatty acid and low polyunsaturated fatty acid (PUFA) levels during the regressing and regenerating stages. At spawning capable and developing stages, a reverse profile was noted. The plasma profiles were mainly influenced by changes in saturated fatty acids and PUFAs in males and by PUFA in females. Based on the most representative fatty acids, four patterns were established for female plasma samples, one for each reproductive stage. This scenario suggests that female plasma samples are promising for the discrimination of gonadal reproductive status, and this potential can be further explored in aquaculture and environmental monitoring studies.

Introduction: The liver is a central metabolic regulator responsible not only for energy storage and allocation but also for the production of essential egg proteins. In seasonal breeders such as brown trout, physiological demands increase during spawning, requiring strong metabolic and structural adaptations. Understanding the cellular mechanisms underlying these fluctuations is essential for clarifying how liver function is regulated during reproduction. Objective: The aim of this study was to investigate cellular mechanisms underlying liver remodelling during the reproductive cycle of male and female brown trout by examining proliferation and apoptosis markers at both molecular and protein levels during four distinct reproductive stages: spawning capable, regressing, regenerating, and developing. Methodology: Adult male and female brown trout were sampled at four reproductive stages. Liver gene expression of proliferating cell nuclear antigen (PCNA) and caspase-3 was analysed using qRT-PCR. At the protein level, liver tissue sections were immunolabelled with antibodies against PCNA and caspase-3. Caspase-3 staining intensity was quantified using ImageJ, while PCNA expression was assessed by counting positively stained nuclei. Results: PCNA gene expression was upregulated during the regressing stage, while PCNA-positive nuclei immunolabelling increased during the regressing and spawning-capable stages. Caspase-3 transcript levels showed no significant differences among stages, whereas immunostaining increased during regenerating and developing stages. Conclusions: Overall, the liver undergoes dynamic cellular remodelling throughout the reproductive cycle, balancing proliferation and apoptosis to meet reproductive demands. The results suggest that proliferation is more evident during regenerating stages, while apoptotic activity may be regulated post-transcriptionally. PCNA also indicates that proliferative activity may persist during spawning capable stages, reflecting ongoing mitotic readiness despite reduced overall proliferation.