Animals

2021

Jump to: 2020

11 pages, 1825 KiB

Open AccessCommunication

Welfare in Nile Tilapia Production: Dorsal Fin Erection as a Visual Indicator for Insensibility

by Bruno Camargo-dos-Santos, Clarissa Lerois Carlos, João Favero-Neto, Nina Pacheco Capelini Alves, Bruno Bastos Gonçalves and Percília Cardoso Giaquinto

Animals 2021, 11(10), 3007; https://doi.org/10.3390/ani11103007 - 19 Oct 2021

Cited by 3 | Viewed by 3016

Abstract

In aquaculture, to ensure animal welfare in pre-slaughter and slaughter stages, it is fundamental that fish are insensible. A method for evaluating fish insensibility is based on visual sensibility indicators (VSI) assessment (i.e., self-initiated behavior, responses to stimuli and reflexes). However, many stimuli [...] Read more.

In aquaculture, to ensure animal welfare in pre-slaughter and slaughter stages, it is fundamental that fish are insensible. A method for evaluating fish insensibility is based on visual sensibility indicators (VSI) assessment (i.e., self-initiated behavior, responses to stimuli and reflexes). However, many stimuli used to assess fish responses are painful. Therefore, this study verifies whether the presence/absence of a dorsal fin erection (DFE) response can be used as a painless VSI in Nile tilapia (Oreochromis niloticus). Three stunning protocols were applied to fish: benzocaine anesthesia (40 mg/L and 80 mg/L), ice water immersion (0–1, 2–3 and 5–6 °C) and CO₂ stunning. After these stunning methods were applied in fish, the time of loss and return of DFE was observed, along with the vestibulo-ocular reflex (VOR). All fish stunned using benzocaine and ice water immersion lose both VSIs, while 95% of fish stunned using CO₂ lose these VSIs. In all treatments, DFEs return quicker than VOR. Therefore, DFE can be used as a VSI in Nile tilapia, which is simple for producers to assess and does not require a painful stimulus. However, the DFE alone does not totally ensure fish insensibility and must be used together with other well-established VSIs at fish farms. Full article

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10 pages, 1502 KiB

Open AccessArticle

Transport and Recovery of Turbot (Scophthalmus maximus) Sedated with MS-222 and Eugenol: Effects on Intermediary Metabolism and Osmoregulation

by Jie Cao, Qi Wang, Weiqiang Qiu, Jun Mei and Jing Xie

Animals 2021, 11(8), 2228; https://doi.org/10.3390/ani11082228 - 29 Jul 2021

Cited by 10 | Viewed by 3863

Abstract

This study focused on the anesthetic waterless keep-alive transport technique for turbot. MS-222 and eugenol were used to anesthetize turbot and then the waterless keep-alive transport was conducted. The blood physiological changes and flesh quality changes of turbot were evaluated after cooling and [...] Read more.

This study focused on the anesthetic waterless keep-alive transport technique for turbot. MS-222 and eugenol were used to anesthetize turbot and then the waterless keep-alive transport was conducted. The blood physiological changes and flesh quality changes of turbot were evaluated after cooling and during the simulated waterless transport. The results show that the temperature lowered from 13 to 2 °C, resulting in a decrease in moisture, fat and protein contents of all samples. Compared to the control turbot, the turbots treated with MS-222 and eugenol presented higher pH and glycogen content. During the simulated waterless transport, the pH, ATP and glycogen contents in MS-222- and eugenol-treated turbots decreased and the IMP and lactate levels increased. For the blood biochemical indices, blood glucose, cortisol and urea nitrogen increased with the increase in transport time in MS-222- and eugenol-treated turbots. At sampling time, the changes in blood physiological indices were significantly higher in the control samples than those in the MS-222- and eugenol-treated samples. The results indicate that the turbot samples treated with MS-222 or eugenol could reduce stress during cooling and simulated waterless transport. Full article

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9 pages, 273 KiB

Open AccessReview

Twenty Years of Research in Seabass and Seabream Welfare during Slaughter

by Ignacio de la Rosa, Pedro L. Castro and Rafael Ginés

Animals 2021, 11(8), 2164; https://doi.org/10.3390/ani11082164 - 22 Jul 2021

Cited by 7 | Viewed by 4456

Abstract

The behavioural responses of fish to a stressful situation must be considered an adverse reaction caused by the perception of pain. Consequently, the handling prior to stunning and the immediacy of loss consciousness following stunning are the aspects to take into account during [...] Read more.

The behavioural responses of fish to a stressful situation must be considered an adverse reaction caused by the perception of pain. Consequently, the handling prior to stunning and the immediacy of loss consciousness following stunning are the aspects to take into account during the slaughtering process. The most common commercial stunning method in seabream and seabass is based on hypothermia, but other methods such as electrical stunning, carbon dioxide narcosis or anaesthetic with clove oil, are discussed in relation to the time to reach the unconsciousness stage and some welfare indicators. Although seawater plus ice slurry is currently accepted in some guidelines of fish welfare well practices at slaughter, it cannot be considered completely adequate due to the deferred speed at which cause loss of consciousness. New methods of incorporating some kind of anaesthetic in the stunning tank could be a solution to minimize the impact on the welfare of seabass and seabream at slaughtering. Full article

20 pages, 14108 KiB

Open AccessArticle

Exploring the Multimodal Role of Yucca schidigera Extract in Protection against Chronic Ammonia Exposure Targeting: Growth, Metabolic, Stress and Inflammatory Responses in Nile Tilapia (Oreochromis niloticus L.)

by Zizy I. Elbialy, Abdallah S. Salah, Ahmed Elsheshtawy, Merna Rizk, Muyassar H. Abualreesh, Mohamed M. Abdel-Daim, Shimaa M. R. Salem, Ahmad El Askary and Doaa H. Assar

Animals 2021, 11(7), 2072; https://doi.org/10.3390/ani11072072 - 12 Jul 2021

Cited by 27 | Viewed by 6228

Abstract

Ammonia is a critical hazardous nitrogen metabolic product in aquaculture. Despite trials for its control, ammonia intoxication remains one of the most critical issues to overcome. In this study, we explored the modulatory effect and potential mechanism by which Yucca schidigera extract (YSE) [...] Read more.

Ammonia is a critical hazardous nitrogen metabolic product in aquaculture. Despite trials for its control, ammonia intoxication remains one of the most critical issues to overcome. In this study, we explored the modulatory effect and potential mechanism by which Yucca schidigera extract (YSE) can ameliorate ammonia intoxication-induced adverse effects on tilapia health and metabolism. A total number of 120 Nile tilapia were evenly assigned into four groups with three replicates each. The first group served as normal control group; the second group was exposed to ammonia alone from the beginning of the experiment and for four weeks. The third group was supplied with YSE in water at a dose of 8 mg/L and exposed to ammonia. The fourth group was supplied with YSE only in water at a dose of 8 mg/L. YSE supplementation succeeded in improving water quality by reducing pH and ammonia levels. Moreover, YSE supplementation markedly alleviated chronic ammonia-induced adverse impacts on fish growth by increasing the final body weight (FBW), specific growth rate (SGR), feed intake and protein efficiency ratio (PER) while reducing the feed conversion ratio (FCR) via improvements in food intake, elevation of hepatic insulin-like growth factor (ILGF-1) and suppression of myostatin (MSTN) expression levels with the restoration of lipid reserves and the activation of lipogenic potential in adipose tissue as demonstrated by changes in the circulating metabolite levels. In addition, the levels of hepato-renal injury biomarkers were restored, hepatic lipid peroxidation was inhibited and the levels of hepatic antioxidant biomarkers were enhanced. Therefore, the current study suggests that YSE supplementation exerted an ameliorative role against chronic ammonia-induced oxidative stress and toxic effects due to its free radical-scavenging potential, potent antioxidant activities and anti-inflammatory effects. Full article

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14 pages, 4953 KiB

Open AccessArticle

Dietary Synbiotics Can Help Relieve the Impacts of Deltamethrin Toxicity of Nile Tilapia Reared at Low Temperatures

by Mahmoud S. Gewaily, Safaa E. Abdo, Eman M. Moustafa, Marwa F. AbdEl-kader, Ibrahim M. Abd El-Razek, Mohamed El-Sharnouby, Mohamed Alkafafy, Sayed Haidar Abbas Raza, Mohammed F. El Basuini, Hien Van Doan and Mahmoud A. O. Dawood

Animals 2021, 11(6), 1790; https://doi.org/10.3390/ani11061790 - 15 Jun 2021

Cited by 27 | Viewed by 4730

Abstract

The optimal water temperature for the normal growth of Nile tilapia is between 26 and 28 °C, and the toxicity of pesticides is strongly related to water temperature. An alternate approach to augmenting the resistance of fish to ambient water toxicity and low [...] Read more.

The optimal water temperature for the normal growth of Nile tilapia is between 26 and 28 °C, and the toxicity of pesticides is strongly related to water temperature. An alternate approach to augmenting the resistance of fish to ambient water toxicity and low water temperature via synbiotic feeding was proposed. In this study, fish were allocated into four groups with 10 fish in each replicate, where they were fed a basal diet or synbiotics (550 mg/kg) and kept at a suboptimal water temperature (21 ± 2 °C). The prepared diets were fed to Nile tilapia for 30 days with or without deltamethrin (DMT) ambient exposure (15 μg/L). The groups were named control (basal diet without DMT toxicity), DMT (basal diet with DMT toxicity), synbiotic (synbiotics without DMT toxicity), and DMT + synbiotic (synbiotics with DMT toxicity). The results displayed upregulated transcription of catalase, glutathione peroxidase, and interferon (IFN-γ) genes caused by DMT exposure and synbiotic feeding when compared with the controls. Moreover, HSP70 and CASP3 genes displayed increased transcription caused by DMT exposure without synbiotic feeding. However, fish fed with synbiotics showed downregulated HSP70 and CASP3 gene expressions. The transcription of IL-1β and IL-8 genes were also decreased by DMT exposure, while fish fed synbiotics showed upregulated levels. DMT exposure resulted in irregular histopathological features in gills, intestine, spleen, and liver tissues, while fish fed synbiotics showed regular, normal, and protected histopathological images. Our results indicated that dietary synbiotics ameliorated histopathological damages in DMT-exposed tilapia through alleviation of oxidative stress and inflammation as well as enhancing the immunity. Full article

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20 pages, 2163 KiB

Open AccessArticle

Environmental Salinity Modifies Mucus Exudation and Energy Use in European Sea Bass Juveniles

by Borja Ordóñez-Grande, Pedro M. Guerreiro, Ignasi Sanahuja, Laura Fernández-Alacid and Antoni Ibarz

Animals 2021, 11(6), 1580; https://doi.org/10.3390/ani11061580 - 28 May 2021

Cited by 13 | Viewed by 3924

Abstract

The European sea bass (Dicentrarchus labrax) is a euryhaline marine teleost that can often be found in brackish and freshwater or even in hypersaline environments. Here, we exposed sea bass juveniles to sustained salinity challenges for 15 days, simulating one hypoosmotic [...] Read more.

The European sea bass (Dicentrarchus labrax) is a euryhaline marine teleost that can often be found in brackish and freshwater or even in hypersaline environments. Here, we exposed sea bass juveniles to sustained salinity challenges for 15 days, simulating one hypoosmotic (3‰), one isosmotic (12‰) and one hyperosmotic (50‰) environment, in addition to control (35‰). We analyzed parameters of skin mucus exudation and mucus biomarkers, as a minimally invasive tool, and plasma biomarkers. Additionally, Na⁺/K⁺-ATPase activity was measured, as well as the gill mucous cell distribution, type and shape. The volume of exuded mucus increased significantly under all the salinity challenges, increasing by 130% at 50‰ condition. Significantly greater amounts of soluble protein (3.9 ± 0.6 mg at 50‰ vs. 1.1 ± 0.2 mg at 35‰, p < 0.05) and lactate (4.0 ± 1.0 µg at 50‰ vs. 1.2 ± 0.3 µg at 35‰, p < 0.05) were released, with clear energy expenditure. Gill ATPase activity was significantly higher at the extreme salinities, and the gill mucous cell distribution was rearranged, with more acid and neutral mucin mucous cells at 50‰. Skin mucus osmolality suggested an osmoregulatory function as an ion-trap layer in hypoosmotic conditions, retaining osmosis-related ions. Overall, when sea bass cope with different salinities, the hyperosmotic condition (50‰) demanded more energy than the extreme hypoosmotic condition. Full article

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13 pages, 932 KiB

Open AccessArticle

High Stocking Density and Food Deprivation Increase Brain Monoaminergic Activity in Gilthead Sea Bream (Sparus aurata)

by Marcos Antonio López-Patiño, Arleta Krystyna Skrzynska, Fatemeh Naderi, Juan Miguel Mancera, Jesús Manuel Míguez and Juan Antonio Martos-Sitcha

Animals 2021, 11(6), 1503; https://doi.org/10.3390/ani11061503 - 22 May 2021

Cited by 9 | Viewed by 2869

Abstract

In teleosts, brain monoamines (dopamine and serotonin) participate in the early response to different acute stressors. However, little is known regarding their role during chronic stress. In a 2 × 2 factorial design, the influence of a high stocking density (HSD) and/or food [...] Read more.

In teleosts, brain monoamines (dopamine and serotonin) participate in the early response to different acute stressors. However, little is known regarding their role during chronic stress. In a 2 × 2 factorial design, the influence of a high stocking density (HSD) and/or food deprivation (FD) on the brain monoaminergic activity in gilthead sea bream (Sparus aurata) was evaluated. Following a 21-day experimental design, samples from the plasma and brain regions (telencephalon, hypothalamus, and optic tectum) were collected. The dopamine (DA), serotonin (5HT), and their main metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and 5 hydroxyindoleacetic acid (5HIAA), contents were HPLC-assessed in brain tissues, and the ratios DOPAC/DA and 5HIAA/5HT were calculated as indicators of enhanced monoaminergic activity. The plasma levels of cortisol and catecholamine were also evaluated. The cortisol levels increased in fish exposed to HSD and normally fed but, also, in all FD groups, whereas the NA levels decreased in LSD-FD animals. Within the brain, the dopaminergic and serotonergic activities in telencephalon and hypothalamus increased in fish subjected to HSD and in the telencephalon of LSD-FD fish. While DA (hypothalamus) and 5HT (telencephalon) increased in the animals submitted to a HSD, food-deprived fish did not show such an increase. Taken together, our results supported the hypothesis of brain monoaminergic activity participating in maintaining and orchestrating the endocrine response to chronic stress in fish. Full article

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18 pages, 3885 KiB

Open AccessArticle

Calibrating Accelerometer Tags with Oxygen Consumption Rate of Rainbow Trout (Oncorhynchus mykiss) and Their Use in Aquaculture Facility: A Case Study

by Walter Zupa, Sébastien Alfonso, Francesco Gai, Laura Gasco, Maria Teresa Spedicato, Giuseppe Lembo and Pierluigi Carbonara

Animals 2021, 11(6), 1496; https://doi.org/10.3390/ani11061496 - 21 May 2021

Cited by 15 | Viewed by 3261

Abstract

Metabolic rates are linked to the energetic costs of different activities of an animal’s life. However, measuring the metabolic rate in free-swimming fish remains challenging due to the lack of possibilities to perform these direct measurements in the field. Thus, the calibration of [...] Read more.

Metabolic rates are linked to the energetic costs of different activities of an animal’s life. However, measuring the metabolic rate in free-swimming fish remains challenging due to the lack of possibilities to perform these direct measurements in the field. Thus, the calibration of acoustic transmitters with the oxygen consumption rate (MO₂) could be promising to counter these limitations. In this study, rainbow trout (Oncorhynchus mykiss Walbaum, 1792; n = 40) were challenged in a critical swimming test (U_crit) to (1) obtain insights about the aerobic and anaerobic metabolism throughout electromyograms; and (2) calibrate acoustic transmitters’ signal with the MO₂ to be later used as a proxy of energetic costs. After this calibration, the fish (n = 12) were implanted with the transmitter and were followed during ~50 days in an aquaculture facility, as a case study, to evaluate the potential of such calibration. Accelerometer data gathered from tags over a long time period were converted to estimate the MO₂. The MO₂ values indicated that all fish were reared under conditions that did not impact their health and welfare. In addition, a diurnal pattern with higher MO₂ was observed for the majority of implanted trout. In conclusion, this study provides (1) biological information about the muscular activation pattern of both red and white muscle; and (2) useful tools to estimate the energetic costs in free-ranging rainbow trout. The use of acoustic transmitters calibrated with MO₂, as a proxy of energy expenditure, could be promising for welfare assessment in the aquaculture industry. Full article

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16 pages, 903 KiB

Open AccessArticle

Aflatoxicosis Dysregulates the Physiological Responses to Crowding Densities in the Marine Teleost Gilthead Seabream (Sparus aurata)

by Andre Barany, Juan Fuentes, Gonzalo Martínez-Rodríguez and Juan Miguel Mancera

Animals 2021, 11(3), 753; https://doi.org/10.3390/ani11030753 - 9 Mar 2021

Cited by 6 | Viewed by 2493

Abstract

Several studies in fish have shown that aflatoxin B1 (AFB1) causes a disparity of species-dependent physiological disorders without compromising survival. We studied the effect of dietary administration of AFB1 (2 mg AFB1 kg⁻¹ diet) in gilthead seabream (Sparus aurata) juveniles [...] Read more.

Several studies in fish have shown that aflatoxin B1 (AFB1) causes a disparity of species-dependent physiological disorders without compromising survival. We studied the effect of dietary administration of AFB1 (2 mg AFB1 kg⁻¹ diet) in gilthead seabream (Sparus aurata) juveniles in combination with a challenge by stocking density (4 vs. 40 g L⁻¹). The experimental period duration was ten days, and the diet with AFB1 was administered to the fish for 85 days prior to the stocking density challenge. Our results indicated an alteration in the carbohydrate and lipid metabolites mobilization in the AFB1 fed group, which was intensified at high stocking density (HSD). The CT group at HSD increased plasma cortisol levels, as expected, whereas the AFB1-HSD group did not. The star mRNA expression, an enzyme involved in cortisol synthesis in the head kidney, presented a ninefold increase in the AFB1 group at low stocking density (LSD) compared to the CT-LSD group. Adenohypophyseal gh mRNA expression increased in the AFB1-HSD but not in the CT-HSD group. Overall, these results confirmed that chronic AFB1 dietary exposure alters the adequate endocrinological physiological cascade response in S. aurata, compromising the expected stress response to an additional stressor, such as overcrowding. Full article

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15 pages, 2123 KiB

Open AccessArticle

Effects of Fouling Management and Net Coating Strategies on Reared Gilthead Sea Bream Juveniles

by Jordi Comas, David Parra, Joan Carles Balasch and Lluís Tort

Animals 2021, 11(3), 734; https://doi.org/10.3390/ani11030734 - 8 Mar 2021

Cited by 10 | Viewed by 2476

Abstract

In aquaculture, biofouling management is a difficult and expensive issue. Cuprous oxide has been commonly used to prevent fouling formation. To cheapen net management and reduce the use of copper, the industry has proposed several alternatives. Currently, polyurethane coatings are being explored and [...] Read more.

In aquaculture, biofouling management is a difficult and expensive issue. Cuprous oxide has been commonly used to prevent fouling formation. To cheapen net management and reduce the use of copper, the industry has proposed several alternatives. Currently, polyurethane coatings are being explored and commercially implemented. With this alternative, net cleaning is done in situ, reducing the number of nets necessary to raise a batch, thus ideally reducing operational costs. This pilot study compared this new strategy to the use of cuprous oxide. The results show that nets treated with antifouling perform better and bioaccumulation of copper in fish tissues do not pose health risks to fish. Alternatives involving on-site cleaning need to improve efficiency. Although the conditions of this work are not completely comparable to commercial aquaculture conditions, the results might indicate the strengths and constrains of the solutions tested in real life. Full article

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19 pages, 3869 KiB

Open AccessArticle

The Lack of Light-Dark and Feeding-Fasting Cycles Alters Temporal Events in the Goldfish (Carassius auratus) Stress Axis

by Nuria Saiz, Miguel Gómez-Boronat, Nuria De Pedro, María Jesús Delgado and Esther Isorna

Animals 2021, 11(3), 669; https://doi.org/10.3390/ani11030669 - 3 Mar 2021

Cited by 17 | Viewed by 3138

Abstract

Vertebrates possess circadian clocks, driven by transcriptional–translational loops of clock genes, to orchestrate anticipatory physiological adaptations to cyclic environmental changes. This work aims to investigate how the absence of a light-dark cycle and a feeding schedule impacts the oscillators in the hypothalamus-pituitary-interrenal axis [...] Read more.

Vertebrates possess circadian clocks, driven by transcriptional–translational loops of clock genes, to orchestrate anticipatory physiological adaptations to cyclic environmental changes. This work aims to investigate how the absence of a light-dark cycle and a feeding schedule impacts the oscillators in the hypothalamus-pituitary-interrenal axis of goldfish. Fish were maintained under 12L:12D feeding at ZT 2; 12L:12D feeding at random times; and constant darkness feeding at ZT 2. After 30 days, fish were sampled to measure daily variations in plasma cortisol and clock gene expression in the hypothalamus-pituitary-interrenal (HPI) axis. Clock gene rhythms in the HPI were synchronic in the presence of a light-dark cycle but were lost in its absence, while in randomly fed fish, only the interrenal clock was disrupted. The highest cortisol levels were found in the randomly fed group, suggesting that uncertainty of food availability could be as stressful as the absence of a light-dark cycle. Cortisol daily rhythms seem to depend on central clocks, as a disruption in the adrenal clock did not impede rhythmic cortisol release, although it could sensitize the tissue to stress. Full article

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2020

Jump to: 2021

11 pages, 1681 KiB

Open AccessArticle

Phenylalanine and Tyrosine as Feed Additives for Reducing Stress and Enhancing Welfare in Gilthead Seabream and Meagre

by Natalia Salamanca, Inmaculada Giráldez, Emilio Morales, Ignacio de La Rosa and Marcelino Herrera

Animals 2021, 11(1), 45; https://doi.org/10.3390/ani11010045 - 29 Dec 2020

Cited by 24 | Viewed by 3532

Abstract

Increased aquaculture production is associated with a growing interest in improving fish welfare. For this reason, the search for strategies to mitigate stress has intensified, one of these strategies being food supplementation with amino acids. The objective of this study was to evaluate [...] Read more.

Increased aquaculture production is associated with a growing interest in improving fish welfare. For this reason, the search for strategies to mitigate stress has intensified, one of these strategies being food supplementation with amino acids. The objective of this study was to evaluate the effects of dietary phenylalanine (Phe) and Tyrosine (Tyr) on the stress response and metabolism of juvenile gilthead seabreams (Sparus aurata) and meagres (Argyrosomus regius). Fish batches were fed a control diet and two diets supplemented with 5% Phe or Tyr for seven days. At the end of the experiment fish were stressed by air exposure for 3 min and then sacrificed for the extraction of blood and brain. Classical plasma stress markers were analyzed (glucose, lactate, proteins, cortisol), as well as hormones derived from those amino acids (adrenaline, noradrenaline and dopamine). Despite interspecific differences, fish fed the diets supplemented with Phe or Tyr showed a reduction on several stress markers. However, interspecific differences were detected for many indicators. Concretely, hormonal stress markers were significantly attenuated in meagres fed the enriched diets. Moreover, the stress condition favored a mobilization of amino acids towards the brain, especially in supplemented diets, hence this amino acid excess could be used as an energy substrate to cope with stress. Full article

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13 pages, 2429 KiB

Open AccessArticle

Coexistence of Three Divergent mtDNA Lineages in Northeast Asia Provides New Insights into Phylogeography of Goldfish (Carssius auratus)

by Lei Cheng, Cuiyun Lu, Le Wang, Chao Li and Xiaoli Yu

Animals 2020, 10(10), 1785; https://doi.org/10.3390/ani10101785 - 1 Oct 2020

Cited by 1 | Viewed by 2095

Abstract

Goldfish (Carassius aurautus), which is a middle size cyprinid, widely distribute throughout Eurasia. Phylogeographic studies using mtDNA markers have revealed several divergent lineages within goldfish. In this study, mtDNA variations were determined to elucidate the phylogeographical pattern and genetic structure of [...] Read more.

Goldfish (Carassius aurautus), which is a middle size cyprinid, widely distribute throughout Eurasia. Phylogeographic studies using mtDNA markers have revealed several divergent lineages within goldfish. In this study, mtDNA variations were determined to elucidate the phylogeographical pattern and genetic structure of goldfish in Northeast Asia. A total of 1054 individuals from Amur river basin were analyzed, which including five newly collected populations and four previously reported populations. Three distinct mtDNA lineages were identified in those samples, two of which corresponded to two known lineages C2 and C6, respectively. The third lineage referred to as C7, following six known lineages of goldfish in mainland Eurasia. AMOVA results suggested that most of the genetic variations were among lineages, rather than among populations or twice samplings. We noted that the control region (CR) and cytochrome b (cytb) sequences of lineage C7 have been reported in previous studies, respectively. However, the evolutionary position and distribution pattern of this lineage was not discussed in the context of the species. Our results showed that “odd” CR and “hidden” cytb sequences from Central Asia represent the same mtDNA lineage of goldfish. The known samples of C7 lineage were collected from Central Asia (Eastern Kazakhstan and Western Mongolia) to East Asia (Northeast China and Far East Russia), which suggested that it had a wider distribution, rather than limit in Central Asia. Full article

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19 pages, 1327 KiB

Open AccessArticle

Evaluation of an Acute Osmotic Stress in European Sea Bass via Skin Mucus Biomarkers

by Borja Ordóñez-Grande, Pedro M. Guerreiro, Ignasi Sanahuja, Laura Fernández-Alacid and Antoni Ibarz

Animals 2020, 10(9), 1546; https://doi.org/10.3390/ani10091546 - 1 Sep 2020

Cited by 16 | Viewed by 3535

Abstract

European sea bass is a marine teleost which can inhabit a broad range of environmental salinities. So far, no research has studied the physiological response of this fish to salinity challenges using modifications in skin mucus as a potential biological matrix. Here, we [...] Read more.

European sea bass is a marine teleost which can inhabit a broad range of environmental salinities. So far, no research has studied the physiological response of this fish to salinity challenges using modifications in skin mucus as a potential biological matrix. Here, we used a skin mucus sampling technique to evaluate the response of sea bass to several acute osmotic challenges (for 3 h) from seawater (35‰) to two hypoosmotic environments, diluted brackish water (3‰) and estuarine waters (12‰), and to one hyperosmotic condition (50‰). For this, we recorded the volume of mucus exuded and compared the main stress-related biomarkers and osmosis-related parameters in skin mucus and plasma. Sea bass exuded the greatest volume of skin mucus with the highest total contents of cortisol, glucose, and protein under hypersalinity. This indicates an exacerbated acute stress response with possible energy losses if the condition is sustained over time. Under hyposalinity, the response depended on the magnitude of the osmotic change: shifting to 3‰ was an extreme salinity change, which affected fish aerobic metabolism by acutely modifying lactate exudation. All these data enhance the current scarce knowledge of skin mucus as a target through which to study environmental changes and fish status. Full article

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13 pages, 1964 KiB

Open AccessFeature PaperArticle

Fin Erosion of Salmo salar (Linnaeus 1758) Infested with the Parasite Caligus rogercresseyi (Boxshall & Bravo 2000)

by Margarita P. González, Sandra L. Marín, Melinka Mancilla, Hernán Cañon-Jones and Luis Vargas-Chacoff

Animals 2020, 10(7), 1166; https://doi.org/10.3390/ani10071166 - 9 Jul 2020

Cited by 6 | Viewed by 2337

Abstract

Fin condition is a simple indicator of fish welfare, which anticipates detrimental effects on fish in aquaculture systems. This study evaluated the fin condition of Salmo salar at different abundances of the parasite Caligus rogercresseyi. Fish were exposed to infestation with copepodids [...] Read more.

Fin condition is a simple indicator of fish welfare, which anticipates detrimental effects on fish in aquaculture systems. This study evaluated the fin condition of Salmo salar at different abundances of the parasite Caligus rogercresseyi. Fish were exposed to infestation with copepodids and the cohort was allowed to develop to the adult stage. The relative fin index was measured. Significant differences between infested and control fish for both pectoral and anal fins were observed. Moreover, there were significant negative relationships between fin condition and parasite abundances for pectoral, anal, and pelvic fins, suggesting that infestations with C. rogercresseyi could be a possible cause for fin damage in Atlantic salmon. Moreover, this damage was associated with increased stress levels, suggesting that damage can be related to physiological changes on infested fish. According to these results, pectoral fin assessments have the potential to provide information on the welfare of fish with C. rogercresseyi infestation. Determining the causes of poor fin development may improve fish welfare, even when infested by parasites. Full article

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