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16 pages, 2900 KiB

Open AccessArticle

Effects of Dietary Ferroporphyrin Supplementation on Growth Performance, Antioxidant Capacity, Immune Response, and Oxygen-Carrying Capacity in Gibel Carp (Carassius auratus gibelio)

by Kai Wang, Lu Zhang, Hualiang Liang, Mingchun Ren, Haifeng Mi, Dongyu Huang and Jiaze Gu

Animals 2024, 14(21), 3104; https://doi.org/10.3390/ani14213104 - 28 Oct 2024

Viewed by 554

Abstract

An eight-week experiment was conducted to study the effects of dietary ferroporphyrin (FPR) supplementation on growth performance, antioxidant capacity, immune response, and oxygen-carrying capacity in gibel carp. The results demonstrated that the addition of FPR increased the moisture content of the whole fish [...] Read more.

An eight-week experiment was conducted to study the effects of dietary ferroporphyrin (FPR) supplementation on growth performance, antioxidant capacity, immune response, and oxygen-carrying capacity in gibel carp. The results demonstrated that the addition of FPR increased the moisture content of the whole fish body. Supplementation with 0.01% FPR significantly increased the plasma albumin (ALB), total protein (TP), and total cholesterol (TC) contents. The addition of 0.03% and 0.04% FPR significantly increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, respectively, while the glucose (GLU), TC, and total triglyceride (TG) levels showed opposite trends. In terms of antioxidant capacity, the 0.03% and 0.04% dietary FPR supplementation increased malondialdehyde (MDA) levels. The activity of glutathione peroxidase (GPx) exhibited an opposite trend to MDA levels. The supplementation of 0.03% of FPR resulted in a notable reduction in mRNA expression levels of nrf2, keap1, cat, and gpx. Regarding immunity, 0.01% FPR supplementation down-regulated the expression levels of il-1β mRNA, while 0.02% FPR down-regulated il-6 and nf-κb expression levels. Furthermore, 0.02% FPR supplementation significantly up-regulated the il-10 mRNA expression levels. In terms of oxygen-carrying capacity, high levels of FPR (0.03% and 0.04%) were found to influence the epo and vegf mRNA expression. In conclusion, the incorporation of dietary 0.01–0.02% FPR improved the immune system of gibel carp without affecting their antioxidant and oxygen-carrying capacity. However, supplementation with higher levels of FPR (0.03–0.04%) led to decreased antioxidant and oxygen-carrying capacity. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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14 pages, 1864 KiB

Open AccessArticle

Dietary Thymol Supplementation Promotes Antioxidant Responses and Thermal Stress Resistance in Rainbow Trout, Oncorhynchus mykiss

by Morteza Yousefi, Seyyed Morteza Hoseini, Yury Anatolyevich Vatnikov, Arfenya Karamyan and Evgeny Vladimirovich Kulikov

Animals 2024, 14(20), 2988; https://doi.org/10.3390/ani14202988 - 16 Oct 2024

Viewed by 552

Abstract

Rainbow trout fingerlings were fed, in triplicate, diets supplemented with 0 (CTL), 50 (50 TM), 100 (100 TM), 200 (200 TM), 400 (400 TM) and 800 (800 TM) mg/kg of thymol, followed by 48 h of thermal stress. Growth performance and humoral immunological [...] Read more.

Rainbow trout fingerlings were fed, in triplicate, diets supplemented with 0 (CTL), 50 (50 TM), 100 (100 TM), 200 (200 TM), 400 (400 TM) and 800 (800 TM) mg/kg of thymol, followed by 48 h of thermal stress. Growth performance and humoral immunological parameters showed no significant responses to dietary thymol concentrations. Fish fed 50–400 mg/kg thymol diets had significantly higher survival after heat stress. Plasma cortisol, glucose, hepatic glutathione peroxidase, glutathione reductase and erythrocyte catalase significantly increased after thermal stress, whereas total plasma antioxidant capacity, ascorbate, and hepatic/erythrocyte reduced-glutathione significantly decreased. There were significant elevations in plasma ascorbate and hepatic glutathione reductase in the 50 TM, 100 TM and 200 TM groups; plasma total antioxidant capacity in the 100 TM and 200 TM groups; hepatic glutathione peroxidase in the 200 TM group; and hepatic-reduced glutathione in the 100 TM, 200 TM and 400 TM groups, compared to CTL. The highest hepatic superoxide dismutase and lowest hepatic malondialdehyde were observed in the 100 TM group before heat stress. These parameters significantly increased after thermal stress in the treatment groups, except in the 100 TM and 200 TM groups. Hepatic catalase showed no significant difference among the treatment groups before thermal stress. Hepatic catalase significantly increased after heat stress in all treatment groups, except in the 100 TM group. Erythrocyte superoxide dismutase significantly increased in the 100 TM group before heat stress, whereas erythrocyte malondialdehyde significantly decreased in the 100 TM and 200 TM groups after thermal stress. Based on the results, 100 mg/kg of thymol can promote antioxidant power and thermal stress resistance in rainbow trout. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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13 pages, 2011 KiB

Open AccessArticle

Enhancement of Thermal Tolerance and Growth Performances of Asian Seabass (Lates calcarifer) Fed with Grape Extract Supplemented Feed

by Salman Akram, Naveen Ranasinghe, Tsung-Han Lee and Chi-Chung Chou

Animals 2024, 14(18), 2731; https://doi.org/10.3390/ani14182731 - 20 Sep 2024

Viewed by 776

Abstract

Cold snaps during the winter present a critical challenge for Asian seabass (Lates calcarifer) in Taiwan, as sudden temperature drops significantly affect their growth and survival. This study explores the effects of dietary grape extract (GE) from Vitis vinifera on the [...] Read more.

Cold snaps during the winter present a critical challenge for Asian seabass (Lates calcarifer) in Taiwan, as sudden temperature drops significantly affect their growth and survival. This study explores the effects of dietary grape extract (GE) from Vitis vinifera on the growth performance, oxidative stress regulation, and thermal tolerance of this commercially valuable fish. Over a 60-day feeding trial, four dietary groups were tested: a control diet without GE and three diets supplemented with GE at 2% (GE20), 3% (GE30), and 4% (GE40) with commercial feed. The results demonstrated that GE supplementation positively influenced growth, with the GE20 group achieving the best weight gain and feed conversion ratio among all groups. The upregulation of the growth-related gene igf-1 in the liver of the GE20 group further supported its superior growth performance. Additionally, GE-fed groups showed increased expression of antioxidant-related genes sod1 and sod2 in the liver, while gpx1 exhibited a significant increase only in the GE20 group, indicating enhanced antioxidant defenses. Cat gene expression remained unchanged, and higher GE doses reduced the expression of gpx1, cat, and igf-1. Furthermore, GE supplementation improved cold tolerance in all treated groups compared to the control. These findings suggest that dietary GE at 20 g/kg is particularly effective in enhancing growth performance and cold tolerance in Asian seabass, offering a promising strategy for boosting fish health and adaptability in aquaculture. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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14 pages, 1844 KiB

Open AccessArticle

High Levels of Erucic Acid Cause Lipid Deposition, Decreased Antioxidant and Immune Abilities via Inhibiting Lipid Catabolism and Increasing Lipogenesis in Black Carp (Mylopharyngodon piceus)

by Yan Liu, Dingfei Ma, Qiangwei Li, Leping Liu, Wenya Gao, Yuanyuan Xie and Chenglong Wu

Animals 2024, 14(14), 2102; https://doi.org/10.3390/ani14142102 - 18 Jul 2024

Cited by 1 | Viewed by 776

Abstract

This study investigated the effects of dietary erucic acid (EA) on growth, lipid accumulation, antioxidant and immune abilities, and lipid metabolism in black carp fed six diets containing varying levels of EA (0.00%, 0.44%, 0.81%, 1.83%, 2.74%, and 3.49%), for 8 weeks. Results [...] Read more.

This study investigated the effects of dietary erucic acid (EA) on growth, lipid accumulation, antioxidant and immune abilities, and lipid metabolism in black carp fed six diets containing varying levels of EA (0.00%, 0.44%, 0.81%, 1.83%, 2.74%, and 3.49%), for 8 weeks. Results showed that fish fed the 3.49% EA diet exhibited lower weight gain, compared to those fed the 0.81% EA diet. In a dose-dependent manner, the serum triglycerides and total cholesterol were significantly elevated in the EA groups. The 1.83%, 2.74%, and 3.49% levels of EA increased alanine aminotransferase and aspartate aminotransferase activities, as well as decreased acid phosphatase and alkaline phosphatase values compared to the EA-deficient group. The hepatic catalase activity and transcriptional level were notably reduced, accompanied by increased hydrogen peroxide contents in the EA groups. Furthermore, dietary EA primarily increased the C22:1n-9 and C20:1n-9 levels, while decreasing the C18:0 and C18:1n-9 contents. In the EA groups, expressions of genes, including hsl, cpt1a, cpt1b, and ppara were downregulated, whereas the fas and gpat expressions were enhanced. Additionally, dietary EA elevated the mRNA level of il-1β and reduced the expression of il-10. Collectively, high levels of EA (2.74% and 3.49%) induced lipid accumulation, reduced antioxidative and immune abilities in black carp by inhibiting lipid catabolism and increasing lipogenesis. These findings provide valuable insights for optimizing the use of rapeseed oil rich in EA for black carp and other carnivorous fish species. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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16 pages, 3368 KiB

Open AccessArticle

Effects of Low-Lipid Diets on Growth, Haematology, Histology and Immune Responses of Parr-Stage Atlantic Salmon (Salmo salar)

by Byoungyoon Lee, Junoh Lee, Saeyeon Lim, Minjae Seong, Hanbin Yun, Sijun Han, Kang-Woong Kim, Seunghan Lee, Seong-Mok Jeong, Mun Chang Park, Woo Seok Hong, Se Ryun Kwon and Youngjin Park

Animals 2024, 14(11), 1581; https://doi.org/10.3390/ani14111581 - 27 May 2024

Viewed by 3637

Abstract

Lipids in fish diets provide energy and play important roles in immunity and metabolism. Atlantic salmon, a species that migrates from freshwater to seawater, requires high energy, especially during smoltification. Juvenile teleosts have low lipid requirements, and a high dietary lipid content is [...] Read more.

Lipids in fish diets provide energy and play important roles in immunity and metabolism. Atlantic salmon, a species that migrates from freshwater to seawater, requires high energy, especially during smoltification. Juvenile teleosts have low lipid requirements, and a high dietary lipid content is known to have negative effects on their growth and digestion. Therefore, this study evaluated the effect of two commercial rainbow trout feeds (low-lipid, 13.41% and 14.6%) on the growth and immune responses of early parr-stage Atlantic salmon compared to commercial salmon feed (high-lipid, 29.52%). Atlantic salmon parr (weight: 14.56 ± 2.1 g; length: 11.23 ± 0.44 cm) were randomly divided into three groups and fed either one of two commercial rainbow trout feeds (RTF1 and RTF2) or the commercial salmon feed (ASF) for 12 weeks. At the end of the feeding trial, growth, haematology, histology and gene expression analyses were performed. There were no significant differences in weight gain rates or feed efficiency between the groups (p > 0.05). Superoxidate dismutase, glutathione peroxidase, lysozyme and immunoglobulin M activities were not different among the experimental groups (p > 0.05). A histological examination of the liver and intestinal tissues showed no pathological symptoms of inflammatory response or lipid accumulation in any of the groups. In an intestinal transcriptome analysis using RNA-seq, the expression levels of several genes linked to lipids, immune-related proteins, cytokines and chemokines did not differ significantly between the groups (p > 0.05). Commercial rainbow trout feed with low lipid content has no clear negative impact on the development of Atlantic salmon during the early parr stage (14.5 to 39.6 g). This study provides basic information for the development of economical feed for early parr-stage Atlantic salmon. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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20 pages, 2465 KiB

Open AccessArticle

Dietary Artemisia arborescens Supplementation Effects on Growth, Oxidative Status, and Immunity of Gilthead Seabream (Sparus aurata L.)

by Odysseas-Panagiotis Tzortzatos, Dimitra K. Toubanaki, Markos N. Kolygas, Yannis Kotzamanis, Efstratios Roussos, Vasileios Bakopoulos, Achilleas Chatzopoulos, Fotini Athanassopoulou and Evdokia Karagouni

Animals 2024, 14(8), 1161; https://doi.org/10.3390/ani14081161 - 11 Apr 2024

Viewed by 1757

Abstract

Fish infectious diseases are one of the main constraints of the aquaculture sector. The use of medicinal plants provides a sustainable way of protection using safe, eco-friendly compounds in a more cost-effective way of treatment, compared to antibiotics. The aim of the present [...] Read more.

Fish infectious diseases are one of the main constraints of the aquaculture sector. The use of medicinal plants provides a sustainable way of protection using safe, eco-friendly compounds in a more cost-effective way of treatment, compared to antibiotics. The aim of the present study is the assessment of Artemisia arborescens (AA) feed-supplementation effects on gilthead seabream (Sparus aurata). Fish with an average initial body weight of 109.43 ± 3.81 g, were divided into two groups based on AA feed composition (A25 and A50). Following two months of ad libitum feeding, the effect of diets on fish weight and length were measured. Fish serum and mucus were analyzed for non-specific immune parameters (nitric oxide, lysozyme, myeloperoxidase, protease-/anti-protease activity, and complement), antibody responses, oxidative stress (cytochrome P450 1A1, metallothionein), and metabolism markers (total protein, alkaline phosphatase, and glucose). Expression levels of antioxidants (sod1, gpx1), cytokines (il-1b, il-10, tfgb1, and tnfa), hepcidin, and heat shock protein grp75 genes were measured in spleen samples. A results analysis indicated that A. arborescens use as a feed supplement has a compromised positive effect on the growth performance, immune response, and blood parameters of gilthead seabream. Overall, the suitability of A. arborescens as an efficient food supplement for gilthead seabream health improvement was investigated, setting the basis for its application assessment in Mediterranean aquaculture. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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24 pages, 6545 KiB

Open AccessFeature PaperArticle

Effects of Dietary Plant Protein Replacement with Insect and Poultry By-Product Meals on the Liver Health and Serum Metabolites of Sea Bream (Sparus aurata) and Sea Bass (Dicentrarchus labrax)

by Valeria Donadelli, Patrizia Di Marco, Alberta Mandich, Maria Grazia Finoia, Gloriana Cardinaletti, Tommaso Petochi, Alessandro Longobardi, Emilio Tibaldi and Giovanna Marino

Animals 2024, 14(2), 241; https://doi.org/10.3390/ani14020241 - 12 Jan 2024

Cited by 5 | Viewed by 1583

Abstract

The liver health of Gilthead sea bream and European sea bass, fed with fish meal-free diets, including various proportions of plant proteins, as well as insect and poultry by-product meals, was investigated through biochemical and histological analyses using a new liver index (LI) [...] Read more.

The liver health of Gilthead sea bream and European sea bass, fed with fish meal-free diets, including various proportions of plant proteins, as well as insect and poultry by-product meals, was investigated through biochemical and histological analyses using a new liver index (LI) formula. Four isoproteic (45% Dry Matter, DM) and isolipidic (20% DM) diets were compared, including a plant-based control diet (CV) and three other test diets, in which 40% of a plant protein-rich ingredient mixture was replaced with meals from Hermetia illucens (H40) or poultry by-product (P40) alone, or in combination (H10P30). The trials lasted 12 and 18 weeks for sea bream and sea bass, respectively. The results obtained thus far highlighted species-specific differences in the physiological response to dietary changes. In sea bream, the biochemical and histological responses suggest favorable physiological and liver health statuses, with higher serum cholesterol (CHO) and triglyceride (TAG) levels, as well as moderate hepatocyte lipid accumulation, with the H10P30 diet compared to the CV (p < 0.05). In sea bass, all diets resulted in elevated serum TAG levels and lipid accumulation in the liver, particularly in fish fed the P40 one (p < 0.05), which resulted in the highest LI, coupled with a higher frequency of severe lipid accumulation, hypertrophy, cord loss, peripheral nuclei displacement, and pyknosis. In conclusion, sea bream adapted well to the test diets, whereas sea bass exhibited altered hepatic lipid metabolism leading to incipient liver steatosis, likely due to the high lipid contents of the diets, including the insect and poultry meals. The LI formula developed in this study proved to be a reliable tool for assessing the effects of dietary changes on the liver health of sea bream and sea bass, consistent with biochemical and histological findings. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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16 pages, 4211 KiB

Open AccessArticle

Tissue Lipid Profiles of Rainbow Trout, Oncorhynchus mykiss, Cultivated under Environmental Variables on a Diet Supplemented with Dihydroquercetin and Arabinogalactan

by Natalia N. Fokina, Irina V. Sukhovskaya, Nadezhda P. Kantserova and Liudmila A. Lysenko

Animals 2024, 14(1), 94; https://doi.org/10.3390/ani14010094 - 27 Dec 2023

Cited by 1 | Viewed by 1194

Abstract

Reared rainbow trout are vulnerable to environmental stressors, in particular seasonal water warming, which affects fish welfare and growth and induces a temperature response, which involves modifications in tissue lipid profiles. Dietary supplements of plant origin, including the studied mix of a flavonoid, [...] Read more.

Reared rainbow trout are vulnerable to environmental stressors, in particular seasonal water warming, which affects fish welfare and growth and induces a temperature response, which involves modifications in tissue lipid profiles. Dietary supplements of plant origin, including the studied mix of a flavonoid, dihydroquercetin and a polysaccharide, arabinogalactan (25 and 50 mg per 1 kg of feed, respectively), extracted from larch wood waste, were shown to facilitate stress tolerance in fish and also to be beneficial for the safety of natural ecosystems and the sustainability of aquaculture production. This four-month feeding trial aimed to determine the effects of the supplement on liver and muscle lipid accumulation and the composition in rainbow trout reared under environmental variables. During periods of environmental optimum for trout, a consistent increase in energy lipid stores, particularly triacylglycerols (2.18 vs. 1.49-fold over a growing season), and an overall increase in lipid saturation due to lower levels of PUFAs, such as eicosapentaenoic (20:5n-3), docosahexaenoic (22:6n-3) and arachidonic (20:4n-6) acids, were observed in both control and supplement-fed fish, respectively. However, in fish stressed by an increase in ambient temperature, dietary supplementation with dihydroquercetin and arabinogalactan reduced mortality (3.65 in control vs. 2.88% in supplement-fed fish, p < 0.05) and alleviated the high-temperature-induced inhibition of lipid accumulation. It also stabilised the membrane phospholipid ratio and moderated the fatty acid composition of fish muscle and liver, resulting in higher levels of n-3 PUFAs and their precursors. Thus, the natural compounds tested are beneficial in accelerating fish tolerance to environmental stressors, reducing mortality and thermal response, and moderately improving fillet quality attributes by increasing the protein/lipid ratio and the abundance of fatty acids essential for human nutrition. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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15 pages, 333 KiB

Open AccessArticle

Impacts of Temperature on the Growth, Feed Utilization, Stress, and Hemato-Immune Responses of Cherry Salmon (Oncorhynchus masou)

by Jang-Won Lee and Balamuralikrishnan Balasubramanian

Animals 2023, 13(24), 3870; https://doi.org/10.3390/ani13243870 - 15 Dec 2023

Cited by 1 | Viewed by 1269

Abstract

Cherry salmon (Oncorhynchus masou) hold commercial value in aquaculture, and there is a need for controlled laboratory studies to isolate the specific effects of temperature on their growth, feeding, and well-being. We examined the effects of different temperatures (10 °C, 14 [...] Read more.

Cherry salmon (Oncorhynchus masou) hold commercial value in aquaculture, and there is a need for controlled laboratory studies to isolate the specific effects of temperature on their growth, feeding, and well-being. We examined the effects of different temperatures (10 °C, 14 °C, 18 °C, and 22 °C) on juvenile cherry salmon (average mass 29.1 g) in triplicate tanks per treatment over eight weeks. The key parameters assessed included growth rate, feed efficiency, stress response, and hemato-immune responses. Our objectives were to determine the most and less favorable temperatures among the four designated temperatures and to assess the adverse effects associated with these less favorable temperatures. The results showed that body weight, growth rates, feed intake, and feed efficiency were significantly higher at 10 °C and 14 °C compared to 18 °C and 22 °C. Reduced appetite and feeding response were observed at 22 °C. Red blood cell parameters were significantly lower at 22 °C. At 10 °C, the results showed significantly increased plasma cortisol levels, gill Na⁺/K⁺-ATPase activity, body silvering, and decreased condition factors, suggesting potential smoltification. The potential smoltification decreased with increasing temperatures and disappeared at 22 °C. Furthermore, the plasma lysozyme concentrations significantly increased at 18 °C and 22 °C. In conclusion, our study identifies 10 °C and 14 °C as the temperatures most conducive to growth and feed performance in juvenile cherry salmon under these experimental conditions. However, temperatures of 22 °C or higher should be avoided to prevent compromised feeding, reduced health, disturbed immune responses, impaired growth, and feed performance. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

15 pages, 2227 KiB

Open AccessArticle

Molecular Cloning, Tissue Distribution, and Pharmacological Characterization of GPR84 in Grass Carp (Ctenopharyngodon Idella)

by Yang Li, Wei-Jia Song, Shao-Kui Yi, Hui-Xia Yu, Hao-Lin Mo, Ming-Xing Yao, Ya-Xiong Tao and Li-Xin Wang

Animals 2023, 13(19), 3001; https://doi.org/10.3390/ani13193001 - 23 Sep 2023

Cited by 1 | Viewed by 1359

Abstract

The G-protein-coupled receptor GPR84, activated by medium-chain fatty acids, primarily expressed in macrophages and microglia, is involved in inflammatory responses and retinal development in mammals and amphibians. However, our understanding of its structure, function, tissue expression, and signaling pathways in fish is limited. [...] Read more.

The G-protein-coupled receptor GPR84, activated by medium-chain fatty acids, primarily expressed in macrophages and microglia, is involved in inflammatory responses and retinal development in mammals and amphibians. However, our understanding of its structure, function, tissue expression, and signaling pathways in fish is limited. In this study, we cloned and characterized the coding sequence of GPR84 (ciGPR84) in grass carp. A phylogenetic analysis revealed its close relationship with bony fishes. High expression levels of GPR84 were observed in the liver and spleen. The transfection of HEK293T cells with ciGPR84 demonstrated its responsiveness to medium-chain fatty acids and diindolylmethane (DIM). Capric acid, undecanoic acid, and lauric acid activated ERK and inhibited cAMP signaling. Lauric acid showed the highest efficiency in activating the ERK pathway, while capric acid was the most effective in inhibiting cAMP signaling. Notably, DIM did not activate GPR84 in grass carp, unlike in mammals. These findings provide valuable insights for mitigating chronic inflammation in grass carp farming and warrant further exploration of the role of medium-chain fatty acids in inflammation regulation in this species. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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17 pages, 9887 KiB

Open AccessArticle

Effects of White Fish Meal Replaced by Low-Quality Brown Fish Meal with Compound Additives on Growth Performance and Intestinal Health of Juvenile American Eel (Anguilla rostrata)

by Wenqi Lu, Haixia Yu, Ying Liang and Shaowei Zhai

Animals 2023, 13(18), 2873; https://doi.org/10.3390/ani13182873 - 9 Sep 2023

Cited by 1 | Viewed by 1454

Abstract

With a reduced supply and increased price of white fish meal (WFM), the exploration of a practical strategy to replace WFM is urgent for sustainable eel culture. A 70-day feeding trial was conducted to evaluate the effects of replacing WFM with low-quality brown [...] Read more.

With a reduced supply and increased price of white fish meal (WFM), the exploration of a practical strategy to replace WFM is urgent for sustainable eel culture. A 70-day feeding trial was conducted to evaluate the effects of replacing WFM with low-quality brown fish meal (LQBFM) with compound additives (CAs) on the growth performance and intestinal health of juvenile American eels (Anguilla rostrata). The 300 fish (11.02 ± 0.02 g/fish) were randomly distributed in triplicate to four groups (control group, LQBFM20+CAs group, LQBFM30+CAs group and LQBFM40+CAs group). They were fed the diets with LQBFM replacing WFM at 0, 20%, 30% and 40%, respectively. The CAs were a mixture of Macleaya cordata extract, grape seed proanthocyanidins and compound acidifiers; its level in the diets of the trial groups was 0.50%. No significant differences were found in the growth performance between the control and LQBFM20+CAs groups (p > 0.05), whereas those values were significantly decreased in LQBFM30+CAs and LQBFM40+CAs groups (p < 0.05). Compared to the control group, the activity of glutamic-pyruvic transaminase was significantly increased in LQBFM30+CAs and LQBFM40+CAs groups, while lysozyme activity and complement 3 level were significantly decreased in those two groups (p < 0.05). There were decreased antioxidant potential and intestinal morphological indexes in the LQBFM30+CAs and LQBFM40+CAs groups, and no significant differences in those parameters were observed between the control group and LQBFM20+CAs group (p > 0.05). The intestinal microbiota at the phylum level or genus level was beneficially regulated in the LQBFM20+CAs group; similar results were not shown in the LQBFM40+CAs group. In conclusion, with 0.50% CA supplementation in the diet, LQBFM could replace 20% of WFM without detrimental effects on the growth and intestinal health of juvenile American eels and replacing 30% and 40%WFM with LQBFM might exert negative effects on this fish species. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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22 pages, 7630 KiB

Open AccessArticle

Dietary High Glycinin Reduces Growth Performance and Impairs Liver and Intestinal Health Status of Orange-Spotted Grouper (Epinephelus coioides)

by Yanxia Yin, Xingqiao Zhao, Lulu Yang, Kun Wang, Yunzhang Sun and Jidan Ye

Animals 2023, 13(16), 2605; https://doi.org/10.3390/ani13162605 - 12 Aug 2023

Cited by 5 | Viewed by 1517

Abstract

The aim of the study was to investigate whether the negative effects of dietary glycinin are linked to the structural integrity damage, apoptosis promotion and microbiota alteration in the intestine of orange-spotted grouper (Epinephelus coioides). The basal diet (FM diet) was [...] Read more.

The aim of the study was to investigate whether the negative effects of dietary glycinin are linked to the structural integrity damage, apoptosis promotion and microbiota alteration in the intestine of orange-spotted grouper (Epinephelus coioides). The basal diet (FM diet) was formulated to contain 48% protein and 11% lipid. Fish meal was replaced by soybean meal (SBM) in FM diets to prepare the SBM diet. Two experimental diets were prepared, containing 4.5% and 10% glycinin in the FM diets (G-4.5 and G-10, respectively). Triplicate groups of 20 fish in each tank (initial weight: 8.01 ± 0.10 g) were fed the four diets across an 8 week growth trial period. Fish fed SBM diets had reduced growth rate, hepatosomatic index, liver total antioxidant capacity and GSH-Px activity, but elevated liver MDA content vs. FM diets. The G-4.5 exhibited maximum growth and the G-10 exhibited a comparable growth with that of the FM diet group. The SBM and G-10 diets down-regulated intestinal tight junction function genes (occludin, claudin-3 and ZO-1) and intestinal apoptosis genes (caspase-3, caspase-8, caspase-9, bcl-2 and bcl-xL), but elevated blood diamine oxidase activity, D-lactic acid and endotoxin contents related to intestinal mucosal permeability, as well as the number of intestinal apoptosis vs FM diets. The intestinal abundance of phylum Proteobacteria and genus Vibrio in SBM diets were higher than those in groups receiving other diets. As for the expression of intestinal inflammatory factor genes, in SBM and G-10 diets vs. FM diets, pro-inflammatory genes (TNF-α, IL-1β and IL-8) were up-regulated, but anti-inflammatory genes (TGF-β1 and IL-10) were down-regulated. The results indicate that dietary 10% glycinin rather than 4.5% glycinin could decrease hepatic antioxidant ability and destroy both the intestinal microbiota profile and morphological integrity through disrupting the tight junction structure of the intestine, increasing intestinal mucosal permeability and apoptosis. These results further trigger intestinal inflammatory reactions and even enteritis, ultimately leading to the poor growth of fish. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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13 pages, 2038 KiB

Open AccessArticle

Molecular Characterization and Functional Analysis of Hypoxia-Responsive Factor Prolyl Hydroxylase Domain 2 in Mandarin Fish (Siniperca chuatsi)

by Yang Yu, Jian He, Wenhui Liu, Zhimin Li, Shaoping Weng, Jianguo He and Changjun Guo

Animals 2023, 13(9), 1556; https://doi.org/10.3390/ani13091556 - 6 May 2023

Cited by 5 | Viewed by 1797

Abstract

With increased breeding density, the phenomenon of hypoxia gradually increases in aquaculture. Hypoxia is primarily mediated by the hypoxia-inducible factor 1 (HIF-1) signaling pathway. Prolyl hydroxylase domain proteins (PHD) are cellular oxygen-sensing molecules that regulate the stability of HIF-1α through hydroxylation. In this [...] Read more.

With increased breeding density, the phenomenon of hypoxia gradually increases in aquaculture. Hypoxia is primarily mediated by the hypoxia-inducible factor 1 (HIF-1) signaling pathway. Prolyl hydroxylase domain proteins (PHD) are cellular oxygen-sensing molecules that regulate the stability of HIF-1α through hydroxylation. In this study, the characterization of the PHD2 from mandarin fish Siniperca chuatsi (scPHD2) and its roles in the HIF-1 signaling pathway were investigated. Bioinformation analysis showed that scPHD2 had the conserved prolyl 4-hydroxylase alpha subunit homolog domains at its C-terminal and was more closely related to other Perciformes PHD2 than other PHD2. Tissue-distribution results revealed that scphd2 gene was expressed in all tissues tested and more highly expressed in blood and liver than in other tested tissues. Dual-luciferase reporter gene and RT-qPCR assays showed that scPHD2 overexpression could significantly inhibit the HIF-1 signaling pathway. Co-immunoprecipitation analysis showed that scPHD2 could interact with scHIF-1α. Protein degradation experiment results suggested that scPHD2 could promote scHIF-1α degradation through the proteasome degradation pathway. This study advances our understanding of how the HIF-1 signaling pathway is regulated by scPHD2 and will help in understanding the molecular mechanisms underlying hypoxia adaptation in teleost fish. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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21 pages, 2219 KiB

Open AccessArticle

Physiological Response of Grower African Catfish to Dietary Black Soldier Fly and Mealworm Meal

by Askale Gebremichael, Balázs Kucska, László Ardó, Janka Biró, Mária Berki, Éva Lengyel-Kónya, Rita Tömösközi-Farkas, Robert Egessa, Tamás Müller, Gergő Gyalog and Zsuzsanna J. Sándor

Animals 2023, 13(6), 968; https://doi.org/10.3390/ani13060968 - 7 Mar 2023

Cited by 8 | Viewed by 3101

Abstract

A six-week experiment was carried out to test the effects of total (100%) and partial (50%) replacement of fish meal in the diet of African catfish growers with black soldier fly (B) meal, yellow mealworm (M) meal, and a 1:1 combination of both [...] Read more.

A six-week experiment was carried out to test the effects of total (100%) and partial (50%) replacement of fish meal in the diet of African catfish growers with black soldier fly (B) meal, yellow mealworm (M) meal, and a 1:1 combination of both (BM) on the production and health of fish. A total of 420 fish with an average initial body weight of 200 ± 0.5 g were randomly distributed in triplicate to seven diet groups (C, B50, B100, M50, M100, BM50, and BM100, respectively). The growth performance and feed utilization of fish fed with partial or total replacement levels of FM with B were not significantly affected (p > 0.05) during the 6 weeks of feeding. In contrast, significant differences were observed between the groups fed with a diet where FM was totally replaced with M meal and the control in terms of final body weight, specific growth rate, feed conversion ratio, protein efficiency ratio, and protein productive value. Among the blood plasma biochemistry parameters, total cholesterol exhibited a significant difference (p = 0.007) between the M treatments and the control diet. The fatty acid profile of the liver was changed with respect to the long-chain polyunsaturated fatty acid content in all experimental groups. Parallel with this, the upregulation of elovl5 and fas genes in liver was found in all experimental groups compared to the control. Overall, this study shows that fish meal cannot be substituted with yellow mealworm meal in the practical diet of African catfish without compromising the growth, health and feed utilization parameters. Full article

(This article belongs to the Special Issue Physiological Responses of Fishes to Nutrition Management and Environmental Stresses)

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