Search Results (129)

The most used technique to assess cortisol in zebrafish is trunk sampling, a terminal procedure. Extracting cortisol non-terminally in adult zebrafish remains challenging, limiting longitudinal studies, and the reduction of the number of zebrafish used in research. This study explored non-terminal methods for cortisol measurement in adult zebrafish under acute and chronic stress, focusing on housing water and skin mucus as alternatives to terminal trunk sampling. Oxidative stress markers (cerebral and hepatic) were also assessed to confirm stress responses. In experiment A, zebrafish were exposed to no stress, acute stress (AS), or chronic stress for 14 days (CS14) to evaluate skin mucus and trunk cortisol as biomarkers. In experiment B, in addition to CS14, a 7-day unpredictable chronic stress protocol (CS7) was tested to discard stress habituation. Results showed significant effects on cerebral oxidative stress: AS increased ROS and AChE activity, CS7 reduced GPx and AChE, and CS14 raised GPx in experiment A, while it increased protein carbonyls and decreased ATPase levels in experiment B. Trunk and skin mucus cortisol increased following AS. Under chronic stress, trunk and skin mucus cortisol levels were not significantly altered, but water cortisol increased at CS7. In conclusion, skin mucus and trunk cortisol levels are reliable biomarkers for acute stress, while water cortisol holds promise for chronic stress. Full article

Aquaculture is a crucial global food production sector that faces challenges in water quality management, food safety, and stress-related health concerns in aquatic species. Cortisol, a key stress biomarker in fish, and Escherichia coli (E. coli) contamination in bivalve mollusks are critical indicators that require sensitive and real-time detection methods. Liquid crystal (LC)-based immunosensors have emerged as a promising solution for detecting biological analytes due to their high sensitivity, rapid response, and label-free optical detection capabilities. Therefore, this study explores the development and application of LC-based immunosensors for the detection of cortisol in artificial and real recirculating aquaculture system (RAS) samples, as well as E. coli in real contaminated water and clam samples during the depuration processes of bivalve mollusks. The biosensors exhibited the capacity to detect cortisol with a response time in seconds and a limit of detection (LOD) of 0.1 ng/mL. Furthermore, they demonstrated specificity to cortisol when tested against different interfering substances, including testosterone, glucose, and cholesterol. Furthermore, it was possible to correlate cortisol concentrations in different filtration stages and track E. coli contamination during depuration. The results confirm the feasibility of LC-based immunosensors as a user-friendly, portable, and efficient diagnostic tool for aquaculture applications. Full article

Objectives: This study investigates the effects of 600 mg/day Ashwagandha root extract on physiological stress biomarkers, perception of recovery, muscle strength and aerobic capacity in team sports athletes during pre-season training, a period associated with elevated cortisol and accumulated training stress. Methods: Fifty-six athletes (26.8 ± 4.4 years, 1.74 ± 0.10 m, 79.4 ± 17.3 kg, 11.0 ± 7.1 career years) across rugby, water polo and football were randomly assigned to an Ashwagandha (ASH; n = 28, 14 males and 14 females) or placebo (PLA; n = 28, 14 males and 14 females) group for 42 days. Salivary biomarkers were assessed after training, muscle strength and aerobic capacity were measured during training, and perception of recovery was evaluated with Hooper Index (HI) the following day. Mixed ANOVA was used to determine group × time interactions and Bonferroni post hoc analyses were conducted for multiple pairwise comparisons. Results: In female athletes, salivary cortisol increased significantly in PLA (p = 0.001), while recovery parameters such as the overall HI score (p = 0.001), Delayed Onset Muscle Soreness (DOMS) (p = 0.008) and perception of fatigue (p = 0.026) scores improved significantly in ASH. In males, salivary cortisone increased significantly in PLA (p = 0.022), while Countermovement Jump (CMJ) improved significantly in ASH (p = 0.018). Pull-up performance increased in both PLA (p = 0.004) and ASH (p < 0.0001) in males. Conclusions: Supplementation with 600 mg/day of Ashwagandha root extract for 42 days may stabilise stress biomarkers, improve perception of recovery and enhance muscle strength in team sports athletes during pre-season training. The trial is registered on ClinicalTrials.gov with the ID NCT07041853. Full article

Global warming and the increasing frequency of marine heatwaves (MHWs) threaten marine ecosystems and aquaculture. For the economically important spotted seabass (L. maculatus), the neuroendocrine basis of its stage-specific thermal responses has yet to be elucidated. This study examined the transcriptomic, physiological, and behavioral adaptations to chronic heat stress in late larval and late juvenile seabass over 14 days. After thermal acclimation, larvae demonstrated a marked behavioral shift, preferring warmer waters (26–34 °C). While heat stress upregulated key thermosensory genes (e.g., trpv1, trpv4) in the brain across both stages, it induced distinct expression profiles in the skin, suggesting a developmental transition from peripheral to central dominance in thermosensation. Brain transcriptomics revealed stage-specific pathway activation: juveniles engaged in neuroactive ligand-receptor interactions and MAPK signaling, whereas larvae showed enrichment in phosphatidylinositol signaling and protein processing. Both stages showed activation of the hypothalamic-pituitary-interrenal (HPI) axis (upregulation of crh, crhr1, crhr2, pomc) and heat shock response (hsp70, hsp90), accompanied by elevated serum cortisol. Notably, energy metabolism diverged significantly: larvae maintained appetite and developed hyperglycemia, while juveniles exhibited severe feeding suppression and hypoglycemia, which was correlated with differential regulation of appetite genes (npy, orexin, cck). Our results elucidate the distinct neuroendocrine mechanisms underlying thermal acclimation in L. maculatus and provide a scientific basis for developing climate-resilient aquaculture practices for this species. Full article

With increasing global demand for fishery products, saline-alkaline aquaculture has emerged as a potential solution. However, limited information exists regarding the tolerance and adaptability of red tilapia (Oreochromis spp.) to alkaline environments. This study evaluated the acute semi-lethal toxicity of alkaline water and its physiological effects on juvenile red tilapia (44.80 ± 1.09 g; 12.84 ± 1.02 cm). Fish were exposed to NaHCO₃ for 96 h at five alkalinity levels (50, 55, 60, 65, and 70 mmol/L). Survival declined significantly with increasing alkalinity, and the 96 h LC₅₀ was 60.66 mmol/L, indicating relatively high alkaline tolerance. Gill tissue and serum samples were collected at 0, 12, 24, 48, and 96 h under 50 mmol/L NaHCO₃ and freshwater (control). Under prolonged alkaline exposure, gill structure exhibited marked alterations, with SLL and ILCMT progressively decreasing over time. Serum antioxidant responses were impaired, showing a sustained decline in SOD activity and a rise in MDA content, indicating the onset of oxidative stress. TAOC, CAT, and GSH-Px displayed a biphasic response, rising initially before declining with continued stress. TP and GLU levels remained largely stable throughout. Energy metabolism indices also shifted dynamically: TC showed a transient increase followed by a decrease, whereas TG and LDH initially declined before rising later in the exposure period. Stress-related markers, including cortisol, T3, ALP, and ACP, were notably elevated during the exposure. Additionally, serum ion concentrations (K⁺, Ca²⁺, Na⁺, Cl⁻) increased gradually over the 96 h period, reflecting progressive osmoregulatory disturbance under alkaline stress. Overall, this study shows that juvenile red tilapia (Oreochromis spp.) have high alkaline tolerance (96 h LC₅₀ = 60.66 mmol/L NaHCO₃), but exposure to alkaline water causes significant physiological stress, affecting gill structure, antioxidant defense, metabolism, and ion balance. These results offer valuable insights into their adaptability to saline-alkaline aquaculture. Full article

Background/Objectives: Research confirms that diet can influence the onset or course of depression. Polyphenols are bioactive plant compounds with proven beneficial effects on health. The aim of this study was to assess the relationship between polyphenol intake and the health status of individuals with major depressive disorder (MDD). Methods: The study included 44 participants. Health status was assessed using questionnaires adapted into Polish, body composition analysis, and laboratory blood tests. Polyphenol intake was estimated using the Phenol-Explorer program. Results: Among men, polyphenol intake was positively associated with glycated hemoglobin levels (R = 0.70; p = 0.038). Lower polyphenol intake in women was associated with poorer physical health (p = 0.014) and overall quality of life (p = 0.013). Polyphenol intake enhanced the effects of visceral fat content, muscle mass, severity of depressive symptoms (positive), and severity of stress symptoms (negative) on triglyceride levels. Polyphenol intake was positively associated with LDL cholesterol levels, and this relationship was attenuated by body water and fat content. Polyphenol intake weakened the relationship between fat content (negative) and quality of life (positive) with cortisol levels (R² = 0.61; p < 0.001). Conclusions: Polyphenols act both directly and mediate the effects of other factors on the health status of individuals with MDD. Despite their proven beneficial effects, further research is needed to explore their potential impact and mechanisms of action in patients with MDD. Full article

The increasing frequency and intensity of heatwaves due to climate change pose significant challenges to sturgeon aquaculture. This study investigated the effects of gradual heat stress (1 °C every 8 h) on two reciprocal hybrid sturgeon strains (Acipenser baerii ♀ × A. schrenckii ♂, (BS hybrid); A. schrenckii ♀ × A. baerii ♂, (SB hybrid)), focusing on their antioxidant defense mechanisms, heat shock protein (HSP) expression, and liver and gill tissue histology. When water temperature raised to 34.3 °C (about 104 h), LOE (loss of equilibrium) individuals appeared. Twenty-four hours after sampling, fifteen BS hybrid sturgeon remained alive, whereas no SB hybrid sturgeon survived. In this study, the slow heat stress significantly elevated the expression of HSP-related genes (hsc70, hsp70, hsp90) in both the liver of BS hybrid sturgeon and the gills of SB hybrid sturgeon. However, in the gills of BS hybrid sturgeon and the liver of SB hybrid sturgeon, the expression of hsp family genes in the experimental groups was either lower than or comparable to the control group. Significant liver damage, including cellular vacuolization and necrosis, was observed in BS hybrids, while SB hybrid sturgeon exhibited more pronounced gill tissue damage. Among the four antioxidant enzymes—superoxide dismutase (SOD), lactate dehydrogenase (LDH), catalase (CAT) glutathione peroxidase (GPx)—only LDH activity was elevated in the hepatic tissue of BS hybrid sturgeon, corresponding to increased serum lactate levels, while gill LDH activity was higher in SB hybrid sturgeon. In both hybrids, LDH activity exhibited an increasing trend in the kidney. However, total antioxidant capacity (T-AOC) remained unchanged across all three tissues. Both plasma cortisol and lactate were substantially affected by thermal stress. MDA remained at a relatively stable level after heat stress and recovery. These results demonstrate differential tissue-specific responses to heat stress in the reciprocal hybrids. More importantly, the BS hybrid sturgeon exhibited significantly higher thermal tolerance and post-stress survival compared to the SB hybrid sturgeon. These findings reveal that the choice of maternal parent is a critical factor influencing heat resistance in these hybrids, providing a key basis for selective breeding programs and optimizing aquaculture management. Full article

Accelerated population growth has driven the search for efficient food production systems such as aquaponics, which integrates aquaculture and hydroponics in a closed-loop configuration. In conventional aquaculture and hydroponic systems, intensification often causes physiological stress, nutrient imbalances, and resource inefficiencies. This study tested the hypothesis that, in an intensive aquaponic configuration, the synergy between aquaculture and hydroponic modules helps mitigate stress, improve nutrient and water use efficiency, and sustain overall performance compared to stand-alone hydroponic and aquaculture systems. The experiment was conducted under greenhouse conditions over three consecutive 180-day cycles, comparing an intensive aquaponic system with aquaculture and hydroponic modules. Tilapia in aquaponics showed 30% lower cortisol and 22% lower glucose (p < 0.05) than in aquaculture, indicating reduced stress. Tomatoes showed 25% higher catalase activity and 18% higher phenolic content (p < 0.05), reflecting moderate oxidative stress. Tilapia productivity reached 38.4 kg m⁻³ (+11.7%), tomato yield was 22.7% lower than in hydroponic conditions, and N–P use efficiencies were 23.3% and 20.7% (p < 0.05). Water use efficiency improved by 17.4%. Despite reduced plant growth, aquaponics decreased fish stress and enhanced nutrient recovery, supporting its potential as a sustainable, resource-efficient alternative for integrated food production under intensive conditions. Full article

Water temperature is a key factor affecting the growth, feeding performance and physiological status of Atlantic salmon parr in aquaculture. To determine optimal conditions, parr (average weight 31.27 ± 0.35 g) were reared for 60 days at 10, 14, 18, and 22 °C. The survival and condition factors were similar across treatments. The growth rate and feed efficiency were highest at 14 °C, coinciding with elevated antioxidant activity. Feed intake was lowest at 10 °C. Whole-body protein and lipid contents remained unaffected, while moisture and ash contents were lowest at 14 °C. Most plasma biochemical indicators were stable; however, total protein was lowest at 14 °C. Glutathione peroxidase activity peaked at 14 °C, whereas cortisol levels remained unchanged. Heat shock proteins (HSP70, HSP90) increased with temperature, while insulin-like growth factor binding proteins (IGFBP1A, IGFBP1B) decreased at temperatures equal to or greater than 18 °C. Interferon alpha (IFNA) and thioredoxin (TRX) were lowest at 14 °C and highest at 22 °C. Overall, 14 °C appears optimal for growth and antioxidant capacity, although molecular stress markers suggest mild physiological trade-offs. These findings can inform temperature management strategies to enhance productivity and welfare in sustainable salmon aquaculture. Full article

The effects of administering 10 mL of maternal bovine appeasing substance (mBAS) or water (control; CT) at weaning (day 0) before transport on feedlot adaptation and efficiency were evaluated in twenty-two Angus-influenced heifers (n = 11/treatment) over 28 days. Body weight (BW), salivary cortisol, blood for complete blood cell count, rectal temperature, chute score and exit speed were collected on days 0, 14 and 27. Intake, feeding duration, frequency and rate, as well as activity and rumination were monitored daily using automated systems. Average daily gain (ADG) and gain-to-feed ratio (G:F) were calculated for each 14-day interval as well as for the entire feeding period. Treated heifers spent less time eating (p ≤ 0.06) on weeks 1 and 2, with greater feeding rate and activity (p < 0.01) in week 1, followed by reduced activity (p ≤ 0.05) in weeks 2, 3 and 4. Rumination was longer (p < 0.05) in weeks 3 and 4, coinciding with greater (p ≤ 0.05) final BW, ADG_0–27, ADG_14–27, and G:F_0–27, G:F_14–27. Lymphocyte and hematocrit were lower (p < 0.05) on days 14 and 27, respectively, and platelets tended to be greater (p = 0.08) than CT for the entire period. Treated heifers achieved numerically greater profit margins than CT. Overall, mBAS enhanced feedlot adaptability post-weaning, improving production efficiency, which may translate into potential profitability; however, this interpretation should be viewed cautiously considering some design limitations. Full article

Intensified aquaculture production has significantly increased farmed fish exposure to various stressors that compromise welfare and productivity, demanding innovative approaches to enhance sustainable production. Aquaculture environments subject fish to multiple stressors. These include high-density housing, handling, transportation, and fluctuating water quality. Such stressors activate the hypothalamic–pituitary–interrenal axis, resulting in a cascade of endocrine responses. This subsequently impairs feeding behavior, growth performance, and immune function. Psychobiotics exert beneficial effects by producing neuroactive compounds, including gamma-aminobutyric acid, short-chain fatty acids, serotonin, and dopamine. Key bacterial genera such as Lactobacillus, Bifidobacterium, Bacillus, and Enterococcus demonstrate significant psychobiotic properties. Experimental evidence from zebrafish and commercially relevant species demonstrates that psychobiotic interventions consistently reduce cortisol levels, normalize stress responses, and improve behavioral outcomes. These effects occur through the microbiome–gut–brain axis, a bidirectional system connecting the nervous and gastrointestinal systems by neural, endocrine, and immune pathways. Nevertheless, significant challenges persist, such as species-specific efficacy, limitations in mechanistic understanding, and the need for standardized evaluation protocols. This review examines psychobiotics as promising interventions for stress management in aquaculture systems. We conclude that psychobiotics may offer a sustainable approach for mitigating aquaculture stress responses and enhancing both fish welfare and production efficiency through targeted microbiome modulation. Full article

Suspended solids are small particles transported in the water column, which can damage marine ecosystems and impair the health of aquatic organisms. This study evaluated the physiological responses of clams (Venerupis philippinarum) and Atlantic Bay scallops (Argopecten irradians) to suspended solid exposure. Four concentrations (100–1000 mg/L) were tested, with a control group maintained at 0 mg/L. At each time point (1, 2, 4, 6, 8, and 12 days), hemolymph samples were collected from five individuals per group to measure GOT, GPT, ALP, and cortisol. Exposure to suspended solids significantly increased these biochemical indicators compared with the control. Quantitative survival analysis showed that Venerupis philippinarum survival declined to 83.3% (25/30) at 500 mg/L and 76.7% (23/30) at 1000 mg/L after 5 days, while the control maintained 100% survival. In Argopecten irradians, survival remained close to 100% in most treatments, with a slight reduction to 83.3% (25/30) at 1000 mg/L. No mortality occurred in the control group without suspended solids, whereas mortality was evident under combined temperature stress and suspended solid exposure. These findings demonstrate that suspended solids induce stress responses in both species, with early mortality in Venerupis philippinarum likely caused by particle adhesion to the gills, leading to reduced respiratory efficiency. Full article

Background/Objectives: This study examined the effects of 2 weeks of betaine versus placebo supplementation (3 g/d) on 60 km cycling performance, gut permeability, and shifts in plasma metabolites. Methods: Participants included 21 male and female non-elite cyclists. A randomized, placebo-controlled, double-blind, crossover design was used with two 2-week supplementation periods and a 2-week washout period. Supplementation periods were followed by a 60 km cycling time trial. Six blood samples were collected before and after supplementation (overnight fasted state), and at 0 h, 1.5 h, 3 h, and 24 h post-exercise. Five-hour urine samples were collected pre-supplementation and post-60 km cycling after ingesting a sugar solution containing lactulose 5 g, ¹³C mannitol 100 mg, and ¹²C mannitol 1.9 g in 450 mL water. Other outcome measures included plasma intestinal fatty acid binding protein-1 (I-FABP), muscle damage biomarkers (serum creatine kinase, myoglobin), serum cortisol, complete blood cell counts, and shifts in plasma metabolites using untargeted metabolomics. Results: The time to complete the 60 km cycling bout differed significantly between the betaine and placebo trials (mean ± SE, 112.8 ± 2.3, 114.2 ± 2.6 min, respectively, (−1.41 ± 0.7 min) (effect size = 0.475, p = 0.042). No trial differences were found for I-FABP (interaction effect, p = 0.076), L:¹³CM (p = 0.559), the neutrophil/lymphocyte ratio (p = 0.171), serum cortisol (p = 0.982), serum myoglobin (p = 0.942), or serum creatine kinase (p = 0.694). Untargeted metabolomics showed that 214 metabolites exhibited significant trial treatment effects and 130 significant trial x time interaction effects. Betaine versus placebo supplementation was linked to significant increases in plasma betaine, dimethylglycine (DMG), sarcosine, methionine, S-adenosylhomocysteine (SAH), alpha-ketoglutaramate, and 5′methylthioadensone (MTA), and decreases in plasma carnitine and numerous acylcarnitines. Conclusions: Betaine supplementation modestly improved 60 km cycling performance but had no effect on gut permeability. The metabolomics data supported a strong influence of 2-week intake of betaine on the one-carbon metabolism pathway during the 24 h recovery period. Full article

Small ruminant production is increasingly affected by heat stress, with recent heat waves highlighting growing economic and welfare-related challenges. Chronic exposure to elevated temperatures disrupts thermoregulation, reduces feed intake, slows growth, compromises meat quality, and increases mortality. This study evaluated the effects of chromium-yeast supplementation at different doses and timepoints on physiological and molecular stress biomarkers in heat-stressed lambs. Forty-eight clinically healthy 6-month-old Katahdin lambs (average weight 20 ± 2.9 kg) were assigned to a 2 × 4 factorial design, with two ambient temperature conditions (heat stress [HS] and thermoneutral [TN]) and four levels of dietary Cr-yeast (0, 0.2, 0.4, and 0.8 mg/kg of dry matter intake). Lambs were housed individually in pens (1.2 × 2.5 m), with ad libitum access to water, and fed a 50:50 corn silage and concentrate diet (excluding mineral premix) twice daily. Blood samples were collected at days 0, 30, and 60 to evaluate plasma cortisol and the expression of hsp60 and hsp70. Chromium bioavailability was assessed by blood levels using absorption chromatography, and glucose clearance was measured at the end of the experiment. Significant reductions in cortisol and hsp70 expression were observed after 30 days of Cr-yeast supplementation under HS conditions (p < 0.05), particularly at the highest dose. For hsp60, a significant reduction was observed at the highest dose on day 30 under HS (p < 0.05). These effects were not sustained on day 60 (p > 0.05). No significant differences were detected under TN conditions (p > 0.05). These findings suggest that Cr-yeast may offer short-term physiological and cellular protection against chronic heat stress in lambs. Full article

Saline–alkaline water resources are globally widespread, and their rational development offers significant potential to alleviate freshwater scarcity. Saline–alkaline water aquaculture farming not only affects fish growth and survival but also impairs reproductive and developmental functions. Largemouth bass (Micropterus salmoides), an economically important fish, has demonstrated excellent high tolerance to such environments, in order to investigate the effects of alkaline water aquaculture environments on its growth performance, sex hormone levels, gonadal development, and molecular adaptation mechanisms. In this study, largemouth bass were chronically exposed to freshwater (0.55 mmol/L), low alkalinity (10 mmol/L), or high alkalinity (25 mmol/L) and cultured for 80 days. Alkalinity exposure more severely impacted the growth rate of females. High alkalinity significantly increased the hepatosomatic index and decreased the gonadosomatic index in both sexes; moreover, it induced oxidative stress in both sexes, evidenced by reduced superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAOC) levels and elevated malondialdehyde (MDA) content. Furthermore, the levels of sex hormones Serum estradiol (E2), 11-ketotestosterone (11-KT), and testosterone were significantly reduced, accompanied by either an elevated ratio of primary oocytes and follicular atresia, or by reduced spermatogenesis. Apoptotic signals appeared in gonadal interstitial cells, with upregulated expression of genes P53, Bax, Casp3, and Casp8. Ultrastructural damage included fewer mitochondria and cristae blurring, further indicating tissue damage causing dysfunction. Transcriptome results showed that oxidative stress damage and energy metabolism imbalance caused by carbonate alkalinity were key to the delayed gonadal development, which was mainly manifested in enrichment of the ECM–receptor interaction and PI3K-Akt signaling pathways in females exposed to low alkalinity, and the GnRH secretion and chemokine signaling pathways in males. Glycosphingolipid biosynthesis and Ferroptosis pathway were enriched in females exposed to high alkalinity, and the Cortisol synthesis and secretion pathway were enriched in males. Overall, high-alkalinity exposure significantly delayed gonadal development in both sexes of largemouth bass, leading to reproductive impairment. Full article