{"title":"Evaluation of global warming effects on juvenile rainbow trout: focus on immunohistochemistry and osmoregulation.","authors":"Zehra Alkan, Boran Karataş, Ahmet Sepil","doi":"10.1007/s10695-024-01431-5","DOIUrl":"10.1007/s10695-024-01431-5","url":null,"abstract":"<p><p>The negative effects of global warming also directly affect aquatic populations. Consequences such as evaporation due to chronic temperature increase, increase in salinity, and increase in stock density per unit volume are potential stress factors. While creating the trial design, an attempt was made to simulate the effects of global warming, especially on species living in salty and brackish water biotopes. In this study, changes in the gills of rainbow trout (Oncorhynchus mykiss) acclimated to 0, 20, and 38 ‰ of saline in the laboratory were examined histologically and immunohistochemically and blood serum osmolarity. In addition, the water temperature was changed, and experiments were carried out at 16, 19, and 22 °C for each salinity group in parallel with the increase in salinity. However, to simulate the decrease in water volume and intensive stocking due to the potential impact of climate change, the study was carried out using 15 fishes in low-volume aquariums (45 L). Tap water that had been kept for at least 3 days was used in the aquariums. To protect the water quality, independent aquariums with sponge filters were used, and since the aim was to keep dissolved oxygen low, no ventilation system other than the sponge filter was used. In order to minimize the deterioration in water quality during the trial, a 15% water change was performed by performing a bottom flush every 4 days and water of the same temperature and salinity was added as much as the reduced volume. In addition, since increasing stock density due to temperature increase and water decrease will cause the amount of dissolved oxygen to decrease, pure oxygen was not entered into any tank throughout the experiment, and the concentration was requested to be at a low level (7 ± 0.13 mg/L) in all groups. The trials were terminated at the end of the 71st day. Increased serum osmolarity values were observed due to the increase in salinity, and the highest serum osmolarity value was measured at 644 mOsm/kg in the 38 ‰ salinity group. Differences between the groups were found to be statistically significant (p < 0.05). It was observed that the number of cells containing Na<sup>+</sup>/K<sup>+</sup>-ATPase increased depending on salinity. Also, the number of chloride cells reached the maximum level in the 38 ‰ salinity group. Due to increasing salt levels, an increase in mucus cells, limited onset hyperplasia, aneurysm, lamellar separation, and necrosis were observed in the gill tissue.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-13"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142767590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elen Monique de Oliveira Sousa, Nayara Yoshimini de Oliveira, Ianka Agra da Silva, Renata Ávila Ozório, Emilly Monteiro Lopes, Maurício Laterça Martins, Mônica Yumi Tsuzuki
{"title":"Use of the microalgae Tisochrysis lutea in a \"green water\" system increases the absorption area in the intestine of larvae of the seahorse Hippocampus reidi Ginsburg, 1933.","authors":"Elen Monique de Oliveira Sousa, Nayara Yoshimini de Oliveira, Ianka Agra da Silva, Renata Ávila Ozório, Emilly Monteiro Lopes, Maurício Laterça Martins, Mônica Yumi Tsuzuki","doi":"10.1007/s10695-024-01428-0","DOIUrl":"10.1007/s10695-024-01428-0","url":null,"abstract":"<p><p>The study aimed to investigate the influence of different microalgae used in green water culture on the intestinal morphology of the seahorse Hippocampus reidi during the first 15 days of life. Four treatments were tested in triplicate, consisting of two microalgae (Tisochrysis lutea-ISO and Chaetoceros muelleri-CHO), used either individually (TISO and TCHO) or combined (TIC 1:1) in larval rearing water, and a treatment without microalgae (TWM). Larvae (6.68 ± 0.55 mm) were fed copepods (Parvocalanus crassirrostris; 2 ind mL<sup>-1</sup>) and rotifers (Brachionus rotundiformis; 8 ind mL<sup>-1</sup>) from the first to the seventh day, and from the eighth day onwards, with Artemia sp. nauplii (2 ind mL<sup>-1</sup>). For the analysis of intestinal histomorphometry, histological analysis of the tissue was performed on day 0 (initial) and after 7 and 15 days. The results demonstrate a significant increase in weight and weight gain of the larvae on the 15th day in the treatments with the addition of the microalgae T. lutea, whether alone or combination with other microalgae, compared to TWM. In relation the intestinal histomorphometry of larvae, the ANCOVA revealed that, on the 7th and 15th day, only the treatments with microalgae significantly affected the surface area of the intestinal villi. The intestinal histomorphometry of larvae from TISO showed higher values of villus height (85.29 ± 1.23 µm<sup>2</sup>) compared to TWM (69.42 ± 2.82 µm<sup>2</sup>) and TCHO (76.92 ± 2.23 µm<sup>2</sup>) (P < 0.05) but did not show significant differences compared to TIC (80.127 ± 2.08 µm<sup>2</sup>), which reflected on the villi surface area. Therefore, larvae from TISO (3603.43 ± 151.31 µm<sup>2</sup>) and TIC (3550.29 ± 120.99 µm<sup>2</sup>) showed significantly higher values of this parameter compared to TWM (3026.79 ± 147.64 µm<sup>2</sup>) and TCHO (3069.09 ± 126.18 µm<sup>2</sup>) (P < 0.05). In conclusion, the protocol for H. reidi larvae rearing in a green water system with the addition of the microalgae T. lutea resulted in an increase in the intestinal absorption area, resulting in improved performance of the larvae.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-12"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142791466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
My Phuong Le, Warren Burggren, Gil Martinez-Bautista
{"title":"Development and sex affect respiratory responses to temperature and dissolved oxygen in the air-breathing fishes Betta splendens and Trichopodus trichopterus.","authors":"My Phuong Le, Warren Burggren, Gil Martinez-Bautista","doi":"10.1007/s10695-024-01411-9","DOIUrl":"10.1007/s10695-024-01411-9","url":null,"abstract":"<p><p>Ventilation frequencies of the gills (f<sub>G</sub>) and the air-breathing organ (f<sub>ABO</sub>) were measured in juveniles and adults of the air-breathing betta (Betta splendens) and the blue gourami (Trichopodus trichopterus) in response to temperature and hypoxia. Ventilatory rates were evaluated after 1 h of exposure to 27 °C (control), 23 and 31 °C (PO<sub>2</sub> = 21.0 kPa), after acute temperature changes (ATC) from 23 to 27, and 27 to 31 °C, and under progressive hypoxia (PH; PO<sub>2</sub> = ~ 21 to 2.5 kPa). Complex, multi-phased ventilatory alterations were evident across species and experimental groups revealing different stress responses and shock reactions (e.g., changes in temperature sensitivity (Q<sub>10</sub>) of f<sub>G</sub> between 1-h exposure and ACT in both species). Female and male gourami showed differences in Q<sub>10</sub> over the temperature range 23-31 °C. No such Q<sub>10</sub> differences occurred in betta. Juveniles of both species showed higher Q<sub>10</sub> for f<sub>ABO</sub> (~ 3.7) than f<sub>G</sub> (~ 2.2). Adult fish exhibited variable Q<sub>10</sub>s for f<sub>G</sub> (~ 1.5 to ~ 4.3) and f<sub>ABO</sub> (~ 0.8 to ~ 15.5) as a function of temperature, suggesting a switch from aquatic towards aerial ventilation in response to thermal stress. During PH, juveniles from both species showed higher f<sub>G</sub> than adults at all oxygen levels. Females from both species showed higher f<sub>G</sub> compared with males. Collectively, our results suggest that environmental cues modulate ventilatory responses in both species throughout ontogeny, but the actual responses reflect species-specific differences in natural habitat and ecology. Finally, we strongly suggest assessing physiological differences between male and female fish to avoid masking relevant findings and to facilitate results interpretation.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-22"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142827683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nururshopa Eskander Shazada, Mohammad Abdul Momin Siddique, Songpei Zhang, Zhijun Ma, Marek Rodina, Otomar Linhart
{"title":"Effect of appropriate extenders to maintain sperm functionality during short-term storage of sterlet (Acipenser ruthenus) sperm with fertilization assay under hatchery conditions.","authors":"Nururshopa Eskander Shazada, Mohammad Abdul Momin Siddique, Songpei Zhang, Zhijun Ma, Marek Rodina, Otomar Linhart","doi":"10.1007/s10695-024-01413-7","DOIUrl":"10.1007/s10695-024-01413-7","url":null,"abstract":"<p><p>Short-term storage and management of sperm in vitro is an easy and economical process in which suitable extenders can be utilized to extend the storage period and prevent sperm function impairment. Therefore, the current study aimed to evaluate the effect of suitable extenders during the short-term storage of sterlet sperm and determine their fertilizing capacity and hatching success. Three extenders containing a composition of 16, 20, and 24 mM NaCl, 1 mM KCl, 0.1 mM CaCl<sub>2</sub>, 10 mM Tris, pH 8.0 with osmolarity of 46, 55, and 62 mOsm/kg, were used to dilute the sperm of four sexually mature sterlet males (n = 4). Using a CASA system, the motility and velocity of undiluted and diluted sperm with extenders (E1 - E3) were assessed over 6 days at 0-2 °C. The short-term stored diluted sperm was then used in the fertilization and hatching assay, and undiluted fresh and stored sperm was used as a control. A two-way factorial analysis of variance (ANOVA) model confirmed significant effects on sperm motility, curvilinear velocity (VCL), and straight-line velocity (VSL) (P < 0.001), as well as their interaction with the extender. The model was decomposed into a one-way ANOVA to examine the impacts of extenders and storage time. With increasing storage periods, the sperm motility and velocity gradually decreased for diluted sperm with three extenders (E1-E3) but sharply decreased for undiluted sperm (Control). The motility of undiluted sperm was found 3.77 ± 4.09% at 4 days, whereas sperm diluted with extenders showed 57.57 ± 12.33% (E1), 64.34 ± 11.86% (E2), and 61.40 ± 12.41% (E3) motility at 6 days. This study explored extenders optimized with higher osmolarity (39-62 mOsm/kg) and lower K<sup>+</sup> (1 mmol/L) as the most suitable medium for storing sterlet sperm for 6 days. After 6 days post storage, sperm diluted with extenders E1-E3 achieved a fertilization rate of 31.29 ± 14.2%, 31.66 ± 8.84%, and 30.67 ± 10.02%, respectively, and hatching success of 29.58 ± 13.4%, 30.50 ± 7.89%, and 27.95 ± 9.62%, respectively with freshly ovulated eggs.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-12"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11611934/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142767420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Physiological and biochemical responses of Labeo rohita to neonicotinoids imidacloprid, clothianidin, and their mixture.","authors":"Sadaya Kumar Gajula, Anand Konkala, Madhusudan Reddy Narra","doi":"10.1007/s10695-024-01412-8","DOIUrl":"10.1007/s10695-024-01412-8","url":null,"abstract":"<p><p>Neonicotinoids, widely used insecticides, pose severe environmental risks due to their persistence in soil and water, adversely affecting non-target organisms and ecosystem integrity. The present study examined the 56 days effects of imidacloprid (66.6 mg/l), clothianidin (30 mg/l), and their combination (33.3 mg/l and 15 mg/l) on Labeo rohita, using one-third of the LC<sub>50</sub> sub-lethal concentrations. Survival, weight gain, and the hepatosomatic index decreased insignificantly in the IMI group and significantly in the CLO and Mix groups. Haematological indicators, including erythrocyte counts, haemoglobin, and haematocrit values, were also significantly reduced. Blood glucose and serum creatinine levels increased, while serum albumin, globulin, and plasma total proteins decreased. White blood cell counts elevated, while immunoglobulin (IgM), respiratory burst, and lysozyme activities were significantly inhibited. Liver, brain and muscle lactate and malate dehydrogenases were elevated, whereas succinate and glutamate dehydrogenases were decreased. Liver aspartate aminotransferase activity was substantially higher than that of brain and muscle, which had considerably higher levels of alanine aminotransferase in muscle than in the brain and liver. Additionally, muscle alkaline phosphatase activity was significantly higher than in the liver and brain, whereas liver acid phosphatase showed a greater elevation than in the muscle and brain. The physiological, haematological, and biochemical indices peaked on day 28 and slight recovery was observed on day 56 (IMI > CLO > Mix). The study highlights that the mixture of insecticides poses greater hazards compared to a single active compound, and the indiscriminate use of these insecticides jeopardizes non-target organisms, ecosystems, and public health.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-13"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142767593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-omics analysis and longitudinal study of reprogramming by dietary creatine to endogenous metabolism in largemouth bass (Micropterus salmoides).","authors":"Haodong Yu, Yukang Nie, Xinping Ran, Shaoyun Li, Keming Rong, Xuezhen Zhang","doi":"10.1007/s10695-024-01417-3","DOIUrl":"10.1007/s10695-024-01417-3","url":null,"abstract":"<p><p>Creatine is a feed additive with physiological pleiotropic properties and also an energy homeostasis protector in vertebrates and is successfully used in terrestrial livestock and aquaculture. Here, two feeding trials were performed to investigate dietary creatine on endogenous creatine metabolism and physiological reprogramming in largemouth bass. The results showed that the endogenous creatine metabolism genes AGAT, GAMT, and SLC6A8 of largemouth bass are highly conserved with the amino acid sequences of other teleosts and are clustered separately from mammals. Among the 16 major tissues in largemouth bass, both creatine synthesis genes (agat, gamt) and transporter gene slc6a8 are most highly expressed in muscle. Muscle has a high threshold but sensitive creatine negative feedback to regulate endogenous creatine metabolism. Dietary creatine intake significantly inhibits endogenous creatine synthesis and transport in muscle in a dose-dependent manner, and this inhibitory effect recovers with a decrease in dietary creatine content. In addition, physiological creatine saturation required prolonged exogenous creatine intake, and it would be shortened by high doses of creatine, which provides guidance for maximizing economic benefits in aquaculture. Metabolome and transcriptome showed that dietary creatine significantly affected the metabolism of the creatine precursor substance-arginine. Exogenous creatine intake spared arginine that would otherwise be used for creatine synthesis, increased arginine levels, and caused reprogramming of arginine metabolism. Overall, these results demonstrate that the addition of creatine to largemouth bass diets is safe and recoverable, and the benefits of creatine intake in largemouth bass are not limited to enhancing the function of creatine itself but also include a reduction in the metabolic burden of essential amino acids to better growth performance.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-18"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142784752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Membrane progesterone receptor e (paqr9) is necessary for chorion elevation in zebrafish.","authors":"Md Razain Tanvir, Takumi Mouri, Eisei Tsutsumi, Umme Habiba Mustary, Md Almamun Farid, Md Forhad Hossain, Yuki Omori, Chihiro Yamamoto, Akiteru Maeno, Toshinobu Tokumoto","doi":"10.1007/s10695-024-01435-1","DOIUrl":"10.1007/s10695-024-01435-1","url":null,"abstract":"<p><p>Paqr9 is a gene encoding membrane progestin receptor e (mPRe), the fifth subtype of the five mPR subtypes, and is currently classified a member of the progestin and adipoQ receptor (PAQR) family, which consists of 11 genes. To elucidate the physiological functions of the mPR subtypes, we established gene knockout (KO) fish via genome editing of seven paqr genes in zebrafish and analyzed their phenotypes. The null-mutant strain of paqr9 (paqr9<sup>-/-</sup>) that we established in this study presented reduced chorion elevation and a high percentage of abnormal embryos. Embryos exhibit various kinds of abnormal morphology, which are thought to be caused by insufficient elevation of the chorion. Immunohistochemical staining of ovaries with an anti-Paqr9 antibody revealed that Paqr9 was expressed in the periplasm of oocytes and the surface of chorion in the wild type, whereas signals were absent in paqr9<sup>-/-</sup> zebrafish. In histological sections, the periplasmic connection between the oocyte plasma membrane and chorion was absent in paqr9<sup>-/-</sup> oocytes. The number of cortical alveoli (CA) that are responsible for chorion elevation was significantly reduced in paqr9<sup>-/-</sup> zebrafish. SEM revealed that fiber-supported knob-like structures (KSs) on the chorion were absent in paqr9<sup>-/-</sup> zebrafish. These results indicate that Paqr9 is required for the preparation of CA during oogenesis. Insufficient formation of the chorion resulted in the abnormal development of embryos.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-12"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142791464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stranded heavy fuel oil exposure causes deformities, cardiac dysfunction, and oxidative stress in marine medaka Oryzias melastigma using an oiled-gravel-column system.","authors":"Zhonglei Ju, Xishan Li, Xin Li, Cen Liang, Zhu Xu, Huishu Chen, Deqi Xiong","doi":"10.1007/s10695-024-01437-z","DOIUrl":"https://doi.org/10.1007/s10695-024-01437-z","url":null,"abstract":"<p><p>Heavy fuel oil (HFO) stranded on the coastline poses a potential threat to the health of marine fish after an oil spill. In this study, an oiled-gravel-column (OGC) system was established to investigate the toxic effects of stranded HFO on marine medaka Oryzias melastigma. HFO 380# (sulfur content 2.9%) was chosen as one type of high sulfur fuel oil for acute toxicity tests. The marine medaka larvae were exposed to the OGC system effluents with oil loading rates of 0 (control), 400, 800, 1600, and 3200 µg HFO/g gravel for 144 h, respectively. Results showed that a prevalence of blue sac disease signs presented teratogenic effects, including decreased circulation, ventricular stretch, cardiac hemorrhage, and pericardial edema. Moreover, the treatments (800, 1600, and 3200 µg oil/g gravel) induced severe cardiotoxicity, characterized by significant bradycardia and reduced stroke volume with an overt decrease in cardiac output. Additionally, the antioxidant enzyme activities, including catalase (CAT), peroxidase (POD), and glutathione S-transferase (GST) were significantly upregulated at 800-3200 µg oil/g gravel except for a marked inhibition of CAT activity at 3200 µg oil/g gravel. Furthermore, significantly elevated protein carbonyl (PCO) levels were detected, suggesting that the organisms suffered severe protein oxidative damage subjected to the exposure. Overall, stranded HFO 380# exposure activated the antioxidant defense system (up-regulated POD and GST activities) of marine medaka and disrupted CAT activity, which could result in an oxidative stress state (elevated PCO levels) and might further contribute to cardiac dysfunction, deformities, and mortality.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-21"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142853609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hanwei Yan, Jinxing Du, Shengjie Li, Caixia Lei, Tao Zhu, Linqiang Han, Hongmei Song
{"title":"Chronic heat stress is capable of reducing the growth performance, causing damage to the liver structure, and altering the liver glucose metabolism and lipid metabolism in largemouth bass (Micropterus salmoides L.).","authors":"Hanwei Yan, Jinxing Du, Shengjie Li, Caixia Lei, Tao Zhu, Linqiang Han, Hongmei Song","doi":"10.1007/s10695-024-01416-4","DOIUrl":"10.1007/s10695-024-01416-4","url":null,"abstract":"<p><p>High temperatures cause abnormal energy metabolism and inhibit the growth of fish in aquaculture. However, the mechanism of energy metabolism under chronic heat stress is still unknown. In this study, largemouth bass (Micropterus salmoides, LMB) was treated with 25℃, 29℃, and 33℃ for 8 weeks. Then, the growth performance, liver tissue damage, serum lipid indicator, hepatic glycogen, and triglyceride levels were analyzed. The growth data showed that the 33℃ group had a lower weight gain rate (WGR), specific growth rate (SGR), feeding rate (FR), and higher feed conversion rate (FCR) in comparison with those in the 25℃ and 29℃ groups. However, there were no significant differences between the 25℃ and 29℃ groups. The most severe damage to liver tissue was observed in the 33℃ group, characterized by cellular vacuolation and marginalization of cell nuclei. The levels of triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol in the serum were decreased with the rising temperatures. However, the hepatic triglyceride levels were increased, with a decrease in hepatic glycogen levels. Compared with the 25℃ group, the expressions of gluconeogenesis pathway-related genes (phosphoenolpyruvate carboxykinase (Pepck) and glucose-6-phosphatase (G6pase)) and glucose transport pathway-related gene (glucose transporter 2 (Gltu2)) were down-regulated in the 33℃ group. In contrast, the expression of the glycolysis pathway-related gene (pyruvate kinase (Pk)) was up-regulated. In addition, the expressions of fatty acid β oxidation pathway-related genes (peroxisome proliferator-activated receptor-Alpha (Pparα) and carnitine palmityl transferase 1 (Cpt1)), adipogenesis pathway-related genes (peroxisome proliferator-activated receptor-Gamma (Pparγ), fatty acid synthase (Fas), acetyl-CoA carboxylase (Acc)), and lipolysis pathway-related genes (adipose triglyceride lipase (Agtl) and hormone-sensitive lipase (Hsl)) were down-regulated under chronic heat stress. In conclusion, our results indicated that enhancement of the glycolysis pathway and inhibition of the gluconeogenesis pathway and lipid metabolism contribute to coping with chronic heat stress for LMB. Our study provides useful information for alleviating the heat stress response of LMB through nutritional regulation in the future.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-12"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142812542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fishmeal intervention after short-term novel proteins stimulates compensatory growth and affects intestinal health in largemouth bass (Micropterus salmoides).","authors":"Lukuan Li, Yu Wang, Xianjun Zhou, Chunfang Wang","doi":"10.1007/s10695-024-01436-0","DOIUrl":"10.1007/s10695-024-01436-0","url":null,"abstract":"<p><p>This research utilized a compensatory growth phenomenon aimed at reducing the use of fishmeal in aquatic animal feed. However, the compensatory growth triggered by fishmeal restriction with novel protein replacement has yet to be understood. Five isonitrogenous and isolipidic diets containing different proteins were manufactured, with fishmeal serving as the control and diets containing novel proteins, i.e., Chlorella (Chlorella vulgaris), cottonseed protein concentrate, Clostridium autoethanogenum, and yellow mealworm (Tenebrio molitor), serving as the experimental diets. Largemouth bass (Micropterus salmoides) with a starting body weight of 4.73 ± 0.04 g were respectively fed these five diets for the first 29 days (first stage), followed by a fishmeal diet for the remaining 29 days (second stage). The diet of fishmeal, Chlorella vulgaris, cottonseed protein concentrate, Clostridium autoethanogenum, and Tenebrio molitor was referred to as FM, ChM, CSM, CAP, and TM, respectively. All novel protein groups showed a 60-73% higher weight gain compared to the fishmeal group during the second phase; however, they did not reach the weight level seen in the control group. In addition, the second stage of fishmeal intervention resulted in a reduction of approximately 35% in the area of positive Alcian blue (AB) staining of intestinal tissues in the CSM group, and about 40% in the CAP group, compared to the first stage. Furthermore, the area of intestinal apoptosis in TM was enlarged after fishmeal intervention while it was decreased in other experimental groups. At day 58, gene expression analysis of the CAP group fish at the end of the trial revealed increased levels of the anti-apoptotic gene bcl-2, as well as higher expression of intestinal inflammatory cytokines il-1β, tnf-α, nf-κb p65, and il-10, compared to the FM group. In terms of the biochemical indices, the levels of catalase (CAT) and glutathione peroxidase (GSH-Px) were reduced in CSM on day 58. An assessment of potential microbial function at end of trial demonstrated that CAP could reduce the lipid metabolism and amino acid metabolism, and increased carbohydrate metabolism pathways in the largemouth bass intestine. In conclusion, both CAP and ChM groups showed promise to reduce fishmeal with respect to intestinal health rather than growth. This study should be of value to practitioners wishing to use novel proteins to reduce fishmeal via the utilization of the compensatory growth phenomenon.</p>","PeriodicalId":12274,"journal":{"name":"Fish Physiology and Biochemistry","volume":"51 1","pages":"1-20"},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142799982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}