Fish Physiology and Biochemistry最新文献

Currently, deacetylated chitin (chitosan) nanoparticles (CNPs) are successfully utilized in aquaculture practices. This trial demonstrates the efficacy of CNPs in combating diazinon (DZN) toxicity in African catfish, Clarias gariepinus, via monitoring hepato-renal function, serum immune trait, hormonal function, and hepato-renal antioxidant activity. Four groups were allocated as follows: a control group, a CNPs group (0.66 ml/L CNPs), a DZN exposed group (0.598 ppm, 1/10 LC50), and a DZN + CNPs group (0.598 ppm DZN + 0.66 ml/L CNPs), all for 30 days. Exposure to 0.598 PPm DZN resulted in a severe decline in the immune parameters (albumin, globulin, immunoglobulins (IgG, IgM), and total proteins), neurological indicator, acetylcholinesterase (AchE), reproductive hormones (Testosterone (T.) and Luteinizing Hormone (LH)), and the superoxide dismutase (SOD) and total antioxidant capacity (TAC) readings in both hepatic and renal samples. Moreover, a clear increment in hepatic and renal indicators (AST, ALT, urea, and creatinine), lipid peroxidation (LPO), and some reproductive indices including follicle stimulating hormone (FSH) and serum 17-β estradiol (E2) was clearly increased. Interestingly, the dietary inclusion of CNPs markedly palliated the toxicity by DZN with significant improvement in the immune-reproductive indices, plus normalizing the values of hepato-renal function and augmenting the activity of antioxidant parameters. Thus, the present study demonstrates the efficacy of CNPs in mitigating low-dose DZN toxicity, resulting in significant improvements in physiological, biochemical, and reproductive parameters. This highlights the promising potential of CNPs as a viable strategy for enhancing the health of C. gariepinus, thereby promoting the sustainability of the aquaculture industry and safeguarding human health.

Stress plays a key role in mental, neurological, endocrine, and immune disorders. The zebrafish (Danio rerio) is rapidly gaining popularity as s model organism in stress physiology and neuroscience research. Although the leopard (leo) fish are a common outbred zebrafish strain, their behavioral phenotypes and stress responses remain poorly characterized. Here, we examined the effects of a 5-week chronic unpredictable stress (CUS) exposure on adult leo zebrafish behavior, cortisol levels, and brain gene expression. Compared to their unstressed control leo counterparts, CUS-exposed fish showed paradoxically lower anxiety-like, but higher whole-body cortisol levels and altered expression of multiple pro- and anti-inflammatory brain genes. Taken together, these findings suggest that behavioral and physiological (endocrine and genomic) responses to CUS do differ across zebrafish strains. These findings add further complexity to systemic effects of chronic stress in vivo and also underscore the importance of considering the genetic background of zebrafish in stress research.

This study examined the energy-dependent physiological responses, including stress, innate immune, and antioxidant systems, as well as indicators of energy mobilization, in pacu (Piaractus mesopotamicus) exposed to intermittent cold, aiming to assess the correlations between these responses. The fish were acclimated to 28 °C, divided into two groups, a control group maintained at 28 °C, and another exposed to 16 °C for two 24 h periods with a 5-day interval between them. The fish were sampled at six time points: baseline (after acclimatization to 28 °C), 24 h after the 1st exposure to 16 °C, after 5 days of recovery at 28 °C, 24 h after the 2nd exposure to 16 °C, and after 24 and 48 h of recovery at 28 °C. The reduction in temperature activated the stress response, the innate immune system, and the antioxidative system as well as mobilized lipids from the visceral stores and preserved the circulating levels of triglycerides. Intermittent exposure of fish to cold increased plasma cortisol after both exposures, activated leukocyte respiratory activity after the 2nd exposure, and triggered the compensatory lysozyme response after temperature recovery in both cold exposures in addition to increasing the number of circulating monocytes and granulocytes. The activity of the enzymes catalase (CAT) and superoxide dismutase (SOD) increased after the 1st and 2nd cold exposures, respectively. Glutathione peroxidase (GPx) activity increased after the 2nd exposure compared to the control. The subtropical fish pacu was sensitive to intermittent cold exposure and was able to display protective physiological responses.

High cadmium (Cd) concentrations pose a threat to aquatic life globally. This study examined the efficiency of adding purslane (Portulaca oleracea L.) leaf powder (PLP) to Oreochromis niloticus diets on Cd's negative effects. PLP was analyzed using high-performance liquid chromatography, and its main constituents were gallic acid, chlorogenic acid, and pyrocatechol. Nile tilapia (180 fish, 34.5 ± 0.5 g) were divided into four groups in triplicate. A basal diet was given to the control group. The PLP group received a basal diet containing 10 g PLP/kg diet. The Cd group was exposed to 50 µg/L water. The Cd + PLP group was exposed to Cd and fed diets containing PLP. Results showed that PLP significantly rescued Cd-induced effects. PLP improved fish survival, feed conversion ratio, and growth retardation caused by Cd. PLP also restored decreased activities of lipase, trypsin, and amylase in the intestine. Furthermore, PLP corrected disturbances in leptin and growth hormone levels induced by Cd. PLP mitigated pathological alterations, replenished antioxidants (SOD, CAT, and GSH), and reduced lipid peroxidation in the intestinal tissues. PLP supplementation depleted significant Cd accumulation in the intestine and muscles. Additionally, PLP corrected altered expressions of tight junction proteins (zo-1, zo-2, and claudin-4) and nutrient transporters (glut-1, slc15a2, slc26a6, and slc4a4) in Cd-exposed fish. Conclusively, PLP shows promise as a dietary supplement to mitigate Cd's harmful impacts on fish growth. Its antioxidant activity and regulation of intestinal tight junction proteins and nutrient transporters contribute to its effectiveness. PLP supplementation holds the potential for reducing the detrimental effects of Cd in aquaculture.

A 60-day feeding trial was conducted to evaluate the combined effect of dietary soy phytoestrogens, specifically genistein and daidzein, on the gonadal recrudescence and maturation of male Cyprinus carpio (Linnaeus, 1758). Adult male C. carpio (60 ± 10 g) were fed with a diet with no added genistein or daidzein (C), 110 mg/100 mg genistein (GL), 210 mg/100 g genistein (GH), 4 mg/100 g daidzein (DL), 8 mg/100 g daidzein (DH), combination of 110 mg/100 mg genistein and 4 mg/100 g daidzein (DGL, equivalent to 17.5% soybean meal) and combination of 210 mg/100 g genistein and 8 mg/100 g daidzein (DGH, equivalent to 35% soybean meal) for 60 days. The fish were spent by injection of the inducing agent before the experiment to maintain the homogeneity in maturity stages. Serum 11-ketotestosterone and 17β-estradiol levels increased substantially (p < 0.05), while serum cortisol and 17α,20β dihydroxy progesterone levels were significantly (p < 0.05) lower in GH, DH, DL, DGL and DGH groups. The gene expression of cyp19a1a and 20β-HSD were significantly downregulated (p < 0.05) in GH, DH, and DGH. The ratio of spermatozoa to spermatocytes was lower in high doses of phytoestrogens and their combination treatments (GH, DH and DGH) than in the lower dose fed groups. The GSI (gonad somatic index) values showed a dose-dependent increase in the isoflavone-fed groups. Hence, the study concluded that the feeding of diets with a combination of 210 mg/100 g genistein and 8 mg/100 g daidzein (DGH), which is equivalent to 35% of soybean meal in the diet, disrupted the sex steroid profile and steroidogenic enzymes expression and caused a delay in maturation in the male common carp. Thus, soybean meal can be included in the diet of male common carp broodstock at levels up to 17.5%. However, inclusion levels above 35% have been shown to impair normal reproductive function.

The current investigation assessed the beneficial impacts of dietary sodium chloride (NaCl) on the growth performance, oxidant/antioxidant, and immune responses of Nile tilapia (Oreochromis niloticus) and its adaptability to different salinity levels. After acclimating the fish to the laboratory conditions for 2 weeks, the acclimated fish (10.5 ± 0.16 g) were randomly distributed into 25 110-L rectangular glass tanks (15 fish/tank) to represent five groups in five replicates. The fish were fed with experimental feeds fortified with 0.0 (control), 5, 10, 15, and 20 g NaCl/kg feed for 60 days. Following the nutritional experiment, fish of all groups were adapted to different salinity levels from 0 to 32 g /L for a further 3 weeks, during which fish mortality was recorded. Blood samples were taken after the feeding trial and at a salinity level of 24 g/L. Growth performance and hematological parameters (WBCs, RBCs, hemoglobin, and hematocrit), total protein, albumin, globulin, digestive enzymes, antioxidant activity, and immunity status were markedly improved with increased NaCl rates in the fish diets up to 10 g/kg feed, after which all previous parameters were declined. On the other hand, feeding fish on a diet containing 10 g NaCl/kg feed showed substantially lower levels of cortisol, glucose, cholesterol, triglycerides, aspartate transaminase (AST), alanine transaminase (ALT), and malondialdehyde (MDA). Exposing the control fish group to salinity stress (32 g/L) for 3 weeks markedly decreased their digestive enzyme activity, immunity status, and antioxidant response, along with significant increases in cortisol, glucose, cholesterol, triglycerides, AST, ALT, and MDA levels. Conversely, feeding fish on a diet containing 10 g NaCl/kg feed alleviated the negative impacts of salinity stress and helped fish to tolerate salinity stress up to 24 g/L.

To identify candidate genes and pathways involved in testicular development in Takifugu rubripes, a comparative transcription analysis was conducted across the various developmental stages of the testis (stages II to V). A total of 9520 differentially expressed genes (DEGs) were identified among the different stages, and they were significantly clustered into six clusters (P < 0.05). One thousand four hundred eleven DEGs such as gndf, wnt1, and cyp17b1 were found to be decreased from stage II to V. In contrast, 994 DEGs such as fn1, ift81, and cdc25a were found to be increased from stage II to V. Six thousand three hundred eighteen DEGs (e.g., dmrt1, sdk2, and chrna1) were identified as being expressed at similar levels at stages II and III. However, they were subsequently found to be decreased from stage III to IV. Four hundred one DEGs exhibited a significant upregulation trend from stage II to III. These genes were expressed at similar levels in stages III, IV, and V, including chrnd, wnt4a, and cyp7a1. The highest expression levels of 200 DEGs (e.g., ccnb2, cdk1, and sycp2) were observed in stage IV, while 196 DEGs (e.g., chmp1b, hsd17b3, and zp3) exhibited the highest expression level in stage III. Those DEGs were mainly enriched in the pathways (e.g., neuroactive ligand-receptor interaction, cell adhesion molecules, and calcium signaling pathways) associated with testicular development. Quantitative polymerase chain reaction of eight randomly selected genes validated the RNA sequencing results. This study may provide new insights into the molecular regulatory mechanisms governing testicular development and spermatogenesis in T. rubripes.

The present study evaluated the potential of Ashoka, Saraca asoca leaf meal (SLM), in carp diets following fermentative processing with a tannase-producing fish gut bacterium, Bacillus subtilis (KP765736). The processing of SLM led to a significant (P < 0.05) reduction in major anti-nutrients (tannin, trypsin inhibitor, and crude fiber), while crude protein content increased. Seven sets of isonitrogenous (35% crude protein) and isocaloric (18.82 kJg^-1) diets were prepared using raw (R1, R2, R3) and fermented SLM (F1, F2, F3) at 10%, 20%, and 30% levels by weight replacing fishmeal and de-oiled rice bran in the reference diet (RD). Diets were fed to rohu, Labeo rohita fingerlings (4.01 ± 0.08 g), for 70 days in triplicate. Fish fed diets containing 30% fermented SLM (F3) exhibited significantly (P < 0.05) better growth (241.25%), improved nutrient utilization, and enhanced activities of digestive enzymes compared to raw SLM-fed groups. Furthermore, tannin accumulation in the liver and muscle was significantly lower (P < 0.05) in fish fed fermented SLM diets compared to those fed raw SLM diets. Additionally, tannin contents in the diets were noticed to be positively correlated (P < 0.05) with tannin accumulation in fish tissues and negatively correlated (P < 0.05) with growth. Hepatic and muscle enzymes associated with carbohydrate metabolism in fish fed RD performed similarly to those reared on fermented SLM diets. Conversely, key enzymes involved in protein metabolism, hexose monophosphate shunt, and the tri-carboxylic-acid cycle showed increased activities in fish fed raw SLM diets, indicating dietary stress and a shift from carbohydrate metabolism to protein catabolism. Moreover, protein, glycogen, and amino acids in hepatopancreas and muscle showed a progressive increase with the gradual inclusion of fermented SLM in the diets. In conclusion, this study might suggest incorporating 30% (w/w) fermented SLM in the diets of rohu without interfering with growth, feed utilization, and metabolic function.

Hydroxycinnamic acid derivatives are a class of phenolic acid compounds, including sinapic acid, ferulic acid, and caffeic acid, which are widely found in plants. This experiment was conducted to study the effects of hydroxycinnamic acid derivatives (sinapic acid, ferulic acid, and caffeic acid) on the growth performance, muscle physical parameters, and intestinal morphology of tilapia. A total of 320 tilapia fingerlings (9.99 ± 0.12 g) were randomly divided into 4 groups with 4 replicates per group and 20 tilapia per replicate. Each group was fed a basal diet (control group), and the experimental diet supplemented with 0.52 mmol/kg sinapic acid, ferulic acid, and caffeic acid, respectively. After 8 weeks of feeding, the growth indexes and serum indexes of tilapia were measured, and the body, muscle composition, and muscle physical parameters, as well as the intestinal morphology were analyzed. The results showed that the addition of hydroxycinnamic acid derivatives to the diets significantly increased the weight gain rate (WGR) compared with the control (p < 0.05), with improvements of approximately 14.93%, 27.27%, and 28.06% for sinapic acid, ferulic acid, and caffeic acid, respectively. In the caffeic acid and ferulic acid groups, the final mean weight (FBW) was significantly increased and the feed coefficient (FCR) was significantly decreased compared with the control (p < 0.05). Compared with the control group, the hydroxycinnamic acid derivatives group had significantly lower levels of aspartate aminotransferase (AST), glucose (GLU), triglyceride (TG), and lactate dehydrogenase (LDH) (p < 0.05), but had significantly higher levels of albumin (ALB), total protein (TP), alkaline phosphatase (ALP), and blood urea nitrogen (BUN) (p < 0.05). There were no significant differences in alanine aminotransferase (ALT) and total cholesterol (TCHO) among all groups (p > 0.05). Besides, moisture, crude protein, crude fat, and ash in whole fish and muscle among all groups showed no significant differences (p > 0.05). In addition, hardness, gumminess, adhesiveness, and resilience of muscle in tilapia fed the hydroxycinnamic acid derivative were significantly higher than that of the control group (p < 0.05). Chewiness, springiness, stringiness, and cohesiveness showed no statistically significant differences among the treatments (p > 0.05). The analysis of intestinal morphology showed that the villus height and muscle thickness of the foregut and hindgut in the fish fed hydroxycinnamic acid derivatives were significantly higher than those in the control fish (p < 0.05), but the villus width of the foregut and hindgut did not differ significantly among the treatment groups (p > 0.05). In conclusion, dietary hydroxycinnamic acid derivatives can improve the growth, muscle physical parameters, and intestinal morphology of tilapia. Ferulic acid and caffeic acid had stronger beneficial effects on tilapia than sinapic acid.