Nucleotides supplementation (Nucleoforce fish™) in Caspian roach (Rutilus caspicus) diet: Growth performance, skin mucosal immune response, and resistance to salinity stress.

In this study, the growth, epidermal mucosal immunity, expression of growth-related genes, cross-protection, and resistance to salinity stress of Caspian roach were scrutinized in response to dietary levels of nucleotides (NT). Accordingly, 1200 fish (0.51 ± 0.01 g) were fed ad libitum with a basal diet (38.88 % crude protein and 10.04 % crude lipid in dry basis) containing incremental levels of NT at 0 (NT-0; control), 0.3 g kg-1 (NT-0.3), 0.6 g kg-1 (NT-0.6), and 1.2 g kg-1 (NT-1.2) for 8 weeks in triplicates. The growth performance was significantly increased in the fish fed with NT-0.6 and NT-1.2 diets compared to the control group (p < 0.05). A significant elevation in the growth hormone and insulin-like growth factor-I gene expression was recorded in NT-added groups at 0.6 and 1.2 g kg-1 compared to the control group (p < 0.05). In contrast to the control group, feeding on NT-0.6 and NT-1.2 diets had a remarkable effect on the skin mucus soluble protein and immunoglobulin levels (p < 0.05). After the feeding trial, we examined how salinity stress (15 g/l salinity) lonely and salinity stress under non-lethal thermal shock (+10 °C) affected heat shock protein (HSP70). Then, the mRNA expression of HSP70 gene from the gill was analyzed at 0, 2, 8, and 24 h post-challenge tests. The HSP70 gene expression level was approximately up-regulated more than 2-fold in NT-6 and NT-1.2 treatments compared to the control group under the salinity stress. Altogether, this research represents that the addition of NT at 0.6 and 1.2 g kg-1 in Caspian roach diet can improve overall performance and resistance to salinity stress.

Therapeutic Role of Hemp (Cannabis sativa) Against Copper-Induced Toxicity in Labeo rohita and Cirrhinus mrigala.

For decades hemp has been used as a therapeutic agent for enhancing immunity in animals. Current study was conceptualized to find out the protective role of dietary hemp seed products (hemp seed oil (HO) and hemp seed (HS)) against copper-induced toxicity in fish. Fingerlings of Labeo rohita (Rohu) and Cirrhinus mrigala (Mrigal) were exposed to copper at 20% of the 96 h LC50 (1.34 and 1.52 ppm, respectively) for 30 days. Following Cu exposure, fish were maintained on two types of hemp (Cannabis sativa)-supplemented feeds, on graded levels of hemp seed oil (HO: 1%, 2%, 3%) and hemp seed (HS: 5%, 10%, 15%) for 50 days, while one group was the control (without any copper exposure as well as any supplementation). Copper exposure significantly increased (P < 0.05) WBCs, hematocrit, MCHV, eosinophils, and lymphocytes in L. rohita and also in C. mrigala as compared to control. Copper exposure also significantly (P < 0.05) changed lysozymes, plasma protein, and IgM in both species, in comparison to control. Moreover, alkaline phosphatase, bilirubin, serum glutamic-pyruvic transaminase, and aspartate transaminase were significantly (P < 0.05) changed by copper exposure in comparison to control in both species. Additionally, Antioxidant enzymes like catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase were also significantly (P < 0.05) increased in the brain, gills, liver, and muscle of copper-exposed group in both species as compared to control. Interestingly, all the altered parameter of blood, serum, liver function tests, and antioxidant enzymes (in different organs) because of copper toxicity were successfully reverted to normal level in hemp seed oil (HO) and hemp seed (HS)-supplemented fed groups of both species. In conclusion, hemp seed supplementation showed significant (P < 0.05) improved results against copper toxicity. Thus, it could be recommended as an animal feed ingredient for its therapeutic role.

Black cardamom (Amomum subulatum) extract improves growth potential, antioxidant status, immune parameters and response to crowding stress in Catla catla.

Natural herbs are excellent alternatives to synthetic compounds to enhance the growth performance and health status of fish. This study was conducted to evaluate the efficacy of black cardamom (Amomum subulatum) extract (BCE) as an herbal supplement in improving the growth, antioxidant status, haematology, and serum biochemistry of Catla catla. The acclimatized fish (N = 900; average initial weight = 14.44 ± 0.33 g) were allocated into five groups (60 fish/group in triplicate) in hapas (4 × 2 × 2.5 ft) and provided with feed containing 0 (control), 0.5, 1, 2 and 4 g/kg BCE for 90 days before being subjected to 8 days of crowding stress. After 90 days, significantly higher feed utilization and growth were observed in all BCE-fed treatments compared to the control; however, the maximum values of these parameters were noted in the 2 g/kg BCE-fed treatment. Moreover, the BCE-fed groups exhibited a significant increase in antioxidant indices (glutathione peroxidase, superoxide dismutase and catalase), with a significant reduction in malondialdehyde levels, indicating a higher antioxidant capacity compared to the control. Significant improvements in haematological parameters, such as an increase in haematocrit, haemoglobin and red blood cells and a decrease in white blood cells, were observed in BCE-fed treatments compared to the control. Furthermore, BCE-fed groups showed a significant decrease in serum glucose, cortisol and triglycerides, while total protein, globulin and albumin levels were significantly higher compared with the control. During the feeding trial of 90 days, no mortality was observed; however, the lowest cumulative mortality was noted in the 2 g/kg BCE group after crowding stress of 8 days. In conclusion, the use of BCE in feed can enhance the growth performance, antioxidant status, haematology, and serum biochemistry of C. catla and improve the resistance against crowding stress. The optimum levels of BCE for C. catla were estimated based on weight gain % (1.78 g/kg; R2 = 0.97), feed conversion ratio (1.65 g/kg; R2 = 0.98), MDA content (1.66 g/kg; R2 = 0.93) and serum lysozyme activity (1.72 g/kg; R2 = 1) using broken-line regression analysis.

Effects of a high-fat and high-carbohydrate diet on appetite regulation and central AMPK in the hypothalamus of blunt snout bream (Megalobrama amblycephala).

Adenosine monophosphate-activated protein kinase (AMPK) is a sensor of cellular energy changes and controls food intake. This study investigates the effect of a high-calorie diet (high fat diet [HFD], high carbohydrate diet [HCD] and high energy diet [HED]) on appetite and central AMPK in blunt snout bream. In the present study, fish (average initial weight 45.84 ± 0.07 g) were fed the control, HFD, HCD and HED in four replicates for 12 weeks. At the end of the feeding trial, the result showed that body mass index, specific growth rate, feed efficiency ratio and feed intake were not affected (p > 0.05) by dietary treatment. However, fish fed the HFD obtained a significantly higher (p < 0.05) lipid productive value, lipid gain and lipid intake than those fed the control diet, but no significant difference was attributed to others. Also, a significantly higher (p < 0.05) energy intake content was found in fish-fed HFD, HCD and HED than those given the control diet. Long-term HFD and HCD feeding significantly increased (p < 0.05) plasma glucose, glycated serum protein, advanced glycation end product, insulin and leptin content levels than the control group. Moreover, a significantly lower (p < 0.05) complex 1, 2 and 3 content was found in fish-fed HFD and HCD than in the control, but no differences (p > 0.05) were attributed to those in HED. Fish-fed HED significantly upregulated (p < 0.05) hypothalamic ampα 1 and ampα 2 expression, whereas the opposite trend was observed in the hypothalamic mammalian target of rapamycin than those in HFD and HCD compared to the control. However, hypothalamic neuropeptide y, peroxisome proliferator-activated receptor α (pparα), acetyl-coa oxidase and carnitine palmitoyltransferase 1 were significantly upregulated (p < 0.05) in the HCD group, while the opposite was seen in cholecystokinin expression compared to those in the control group. Our findings indicated that the central AMPK signal pathway and appetite were modulated according to the diet's energy level to regulate nutritional status and maintain energy homoeostasis in fish.

Cross-species apical microinjected selenomethionine toxicity in embryo-larval fishes.

Selenium (Se) is an essential micronutrient that becomes toxic when exposures minimally exceed those that are physiologically required. Studies on Se contaminated aquatic environments have identified that embryo-larval fishes are at particular risk of Se toxicity, primarily due to maternal Se transfer to developing eggs during oogenesis. This study emulated these exposures in embryo-larval fathead minnow (FHM), rainbow trout (RBT), white sucker (WSu), and white sturgeon (WSt) using embryonic selenomethionine (SeMet) microinjections. Adverse Se-outcomes observed across these species included spinal and edematous deformities, total individuals deformed, and reduced survival. Spinal deformity was the most sensitive sublethal endpoint and developed at the lowest concentrations in WSt (10 % effects concentration (EC10) = 12.42 µg (total) Se/g dry weight (d.w.)) followed by WSu (EC10 = 14.49 µg Se/g d.w.) and FHM (EC10 = 18.10 µg Se/g d.w.). High mortality was observed in RBT, but SeMet influences were confounded by the species' innate sensitivity to the microinjections themselves. 5 % hazardous concentrations derived across exposure type data subsets were ∼49 % higher when derived from within-species maternal transfer exclusive data as opposed to all, or within-species microinjection exclusive, data. These results support the current exclusion of SeMet microinjections during regulatory guideline derivation and their inclusion when studying mechanistic Se toxicity across phylogenetically distant fishes.

Potentials of Aloe barbadensis inclusion in fish feeds on resilience to Aeromonas hydrophila infection in freshwater fish Labeo rohita.

Aquatic bacterial pathogens can cause severe economic loss in aquaculture industry. An opportunistic pathogen, Aeromonas hydrophila is responsible for Motile Aeromonas Septicemia, leading to high mortality rates in fish. The present study was focused on the efficacy of Aloe barbadensis replacing fishmeal diets on hematological, serum biochemical, antioxidant, histopathological parameters, and disease resistance against A. hydrophila infection in Labeo rohita. Isonitrogenous fishmeal replaced diets (FMR) were prepared with varying levels of A. barbadensis at D1 (0%) (control), D2 (25%), D3 (50%), D4 (75%) and D5 (100%) then fed to L. rohita. After 60 days of post-feeding, the experimental fish were challenged with A. hydrophila. Blood and organs were collected and examined at 1- and 15-days post infection (dpi). The results demonstrated that on 1 dpi, white blood cells (WBC), total protein, cholesterol and low-density lipoprotein (LDL) levels were significantly increased in D3 diet fed groups. The D2 and D3 diet fed group showed decreasing trends of serum glutamic pyruvic transaminase (SGPT) and antioxidant enzymes activity on 15 dpi. The histopathological architecture results clearly illustrated that the D3 diet fed group had given a higher protective effect by reducing the pathological changes associated with A. hydrophila infection in liver, intestine and muscle. Higher percentage of survival rate was also observed in D3 diet fed group. Therefore, the present study suggested that the dietary administration of A. barbadensis up to 50% fishmeal replacement (D3 diet) can elicit earlier antioxidant activity, innate immune response and improve survival rate in L. rohita against A. hydrophila infection.

Immuno-physiological effects of dietary reishi mushroom powder as a source of beta-glucan on Rohu, Labeo rohita challenged with Aeromonas veronii.

Beta-glucans have immense potential to stimulate immune modulation in fish by being injected intramuscularly, supplemented with feed or immersion routes of administration. We studied how supplementing Labeo rohita's diet with reishi mushroom powder containing beta-glucan influenced immunological function. A supplemented diet containing 10% reishi mushroom powder was administered for 120 days. Afterwards, analyses were conducted on different immunological parameters such as antioxidants, respiratory burst, reactive oxygen species (ROS), alternative complement activity, and serum immunoglobulin, which resulted significant increases (p < 0.05; p < 0.01) for the reishi mushroom-fed immune primed L. rohita. Additionally, analyzing various hematological parameters such as erythrocytes and leukocytes count were assessed to elucidate the immunomodulatory effects, indicating positive effects of dietary reishi mushroom powder on overall fish health. Furthermore, the bacterial challenge-test with 1.92 × 104 CFU/ml intramuscular dose of Aeromonas veronii showed enhanced disease-defending system as total serum protein and lysozyme activity levels accelerated significantly (p < 0.01). Nevertheless, reishi mushroom powder contained with beta-glucan ameliorated the stress indicating parameters like acetylcholinesterase (AChE), serum-glutamic pyruvic transaminase (SGPT) and serum-glutamic oxaloacetic transaminase (SGOT) enzyme activities results suggested the fish's physiology was unaffected. Therefore, the results indicated that adding dietary reishi mushroom as a source of beta-glucan could significantly boost the immune responses in Rohu.

A trait-based approach to determine the risks of Zn to the overall health status of native fish species Barbus meridionalis.

Fish adapt to changing environments by maintaining homeostasis or making energy trade-offs that impact fitness. We investigated the effect of Zn on the fitness and physiology of Barbus meridionalis, a native cyprinid fish species, under two exposure scenarios. The Osor stream's mine-effluent reach represented long-term (chronic) exposure, while the upstream reach served as a control/acute exposure. Acute exposure involved exposing B. meridionalis to 1mg/L Zn for 96 h in the laboratory. We examined physiological traits (Standard metabolic rate SMR, Maximum metabolic rate MMR, Absolute Aerobic scope AAS, Critical swimming capacity Ucrit) and antioxidant system, AS (Superoxide dismutase, SOD; Catalase, CAT; Glutathione peroxidase, GPX; Glutathione-S-transferase, GST; Glutathione, GSH; Thiobarbaturic acid reactive substances, TBARS) biomarkers. The results indicated that Zn had no significant effect on osmoregulatory cost (SMR) in either exposure scenario but impaired energetically costly exercise (low MMR). AAS reduction in both exposure groups suggested compromised energy allocation for life-history traits, evidenced by decreased locomotor performance (Ucrit) after acute exposure. Tissue-specific and time-dependent responses were observed for AS biomarkers. The fish exhibited ineffective control of oxidative damage, as evidenced by high TBARS levels in the liver and gills, despite increased CAT and GSH in the liver under acute conditions. Our findings demonstrate differential responses at the subcellular level between the two exposure scenarios, while trait-based endpoints followed a similar pattern. This highlights the utility of a trait-based approach as a supplementary endpoint in biomonitoring studies, which provides insights into impacts on individual fitness and population demography.

Fructooligosaccharide and Bacillus subtilis synbiotic combination promoted disease resistance, but not growth performance, is additive in fish.

Species diversification from major to minor carps for their sturdiness and initial higher growth, and also a quest for antibiotic-free aqua farming in the subcontinent, mandates search for and evaluation of alternatives. An experiment was performed to investigate the potential of fructooligosaccharide (FOS) and Bacillus subtilis (BS) (alone or as synbiotics) in promoting growth and immunity against infections in Labeo fimbriatus fingerlings. Six iso-nitrogenous and iso-lipidic diets containing combinations of two levels of FOS (0% and 0.5%) and three levels of BS (0, 104, 106 CFU/g feed) were fed to fish for 60 days. At the end of the feeding trial, twenty-four fish from each group were injected intra-peritoneally with pathogenic strain of Aeromonas hydrophila O:18 to test the immunoprotective efficacy of the supplements against bacterial infection. BS, but not FOS, significantly improved (P < 0.05) growth and feed utilisation attributes like percentage weight gain (PWG), specific growth rate (SGR) and feed conversion ratio (FCR). There were interactive effects of FOS and BS on PWG, SGR and FCR; however, the effects were not additive in nature. These beneficial effects of BS, alone or in combination with FOS, were corroborated by increased protease activity, microvilli density and diameter and number of goblet cells. Overall beneficial effects of FOS and BS included improved erythrocyte (RBC), hemoglobin (Hb), total protein and globulin levels. Total leucocyte (WBC) count and immunological parameters like respiratory burst activity of leucocytes (NBT reduction), lysozyme activity, albumin: globulin ratio and post-challenge survival were significantly improved by both FOS and BS, and their dietary combination yielded the highest improvement in these parameters. Synergistic effects of FOS and BS as dietary supplements indicate that a combination of 106 CFU/g BS and 0.5% FOS is optimal to improve growth, feed utilisation, immune functions, and disease resistance in L. fimbriatus fingerlings.

Expanding non-invasive approaches for fish-health monitoring: A survey of the epidermal mucous metabolomes of phylogenetically diverse freshwater fish species.

There is a pressing need for more-holistic approaches to fisheries assessments along with growing demand to reduce the health impacts of sample collections. Metabolomic tools enable the use of sample matrices that can be collected with minimal impact on the organism (e.g., blood, urine, and mucus) and provide high-throughput, untargeted biochemical information without the requirement of a sequenced genome. These qualities make metabolomics ideal for monitoring a wide range of fish species, particularly those under protected status. In the current study, we surveyed the relative abundances of 120 endogenous metabolites in epidermal mucus across eight freshwater fish species belonging to seven phylogenetic orders. Principal component analysis was used to provide an overview of the data set, revealing strong interspecies relationships in the epidermal mucous metabolome. Normalized relative abundances of individual endogenous metabolites were then used to identify commonalities across multiple species, as well as those metabolites that showed notable species specificity. For example, taurine was measured in high relative abundance in the epidermal mucus of common carp (Cyprinus carpio), northern pike (Esox lucius), golden shiner (Notemigonus crysoleucas), rainbow trout (Oncorhynchus mykiss), and rainbow smelt (Osmerus mordax), whereas γ-amino butyric acid (GABA) exhibited a uniquely high relative abundance in flathead catfish (Pylodictis olivaris). Finally, hierarchical cluster analysis was used to evaluate species relatedness as characterized by both the epidermal mucous metabolome (phenotype) and genetic phylogeny (genotype). This comparison revealed species for which relatedness in the epidermal mucous metabolome composition closely aligns with phylogenetic relatedness (e.g., N. crysoleucas and C. carpio), as well as species for which these two measures are not well aligned (e.g., P. olivaris and Polyodon spathula). These, and other findings reported here, highlight novel areas for future research with fish, including development of epidermal mucous-based markers for non-invasive health monitoring, sex determination, and hypoxia tolerance.

Maternal Transfer and Effects of Selenium on Early Life Stage Development of Redside Shiner (Richardsonius balteatus).

Maternal transfer of selenium (Se) to developing fish eggs during vitellogenesis can cause larval deformity and mortality. Previous studies have shown wide variation among fish species in both the magnitude of maternal transfer (exposure) and the egg Se concentration causing effects (sensitivity). We studied maternal transfer and effects of Se on early life stage development, survival, and growth of redside shiner (Richardsonius balteatus), a small-bodied cyprinid that has been reported to have relatively high ovary:muscle Se concentration ratios. Gametes were collected from lentic areas in southeast British Columbia (Canada) with a range of dietary Se concentrations related to weathering of waste rock from coal mining. Eggs were fertilized and reared in the laboratory from hatch to the onset of exogenous feeding. Larvae were assessed for survival, length, weight, Se-characteristic deformities, and edema. Eggs from a total of 56 females were collected, with egg Se concentrations from 0.7 to 28 mg/kg dry weight. Maternal transfer varied among sites, with egg:muscle Se concentration ratios ranging from <1 to >4. We also found that sampling residual ovaries can overestimate Se concentrations in ripe eggs by up to a factor of 5.7. A correlation between larval weight and egg Se concentration was identified, although the relationship was weak (r2 < 0.1) and appeared to be a site effect. No other relationships were observed between larval endpoints and egg Se concentrations up to the highest concentration tested, indicating that the effects threshold for this species may be >28 mg/kg dry weight in eggs. These data indicate that redside shiner is less sensitive to maternally transferred Se than most other tested fish species. Environ Toxicol Chem 2023;42:2350-2357. © 2023 SETAC.

Dietary berberine against intestinal oxidative stress, inflammation response, and microbiota disturbance caused by chronic copper exposure in freshwater grouper (Acrossocheilus fasciatus).

Berberine (BBR) is known for its strong antioxidant, anti-inflammatory, and capacity to preserve intestinal microbiota balance in fish. This study aimed to investigate the protective effects of berberine against copper-induced toxicity in the intestine of freshwater grouper Acrossocheilus fasciatus. The experiment involved four groups: a control group, a Cu group exposed to 0.02 mg/L Cu2+, and two BBR groups fed with 100 or 400 mg/kg of berberine diets and exposed to the same Cu2+ concentration. Three replicates of healthy fish (initial weight 1.56 ± 0.10 g) were subjected to their respective treatments for 30 days. Results showed that none of the treatments significantly affected the survival rate, final weight, weight gain, and feed intake (P > 0.05). However, supplementation with 100 and 400 mg/kg of BBR significantly lowered the antioxidant activities, and glutathione peroxidase (gpx) and superoxide dismutase (sod) expression levels, as well as reduced malondialdehyde (MDA) content caused by Cu2+ exposure (P < 0.05). Berberine inclusion significantly downregulated proinflammatory factors NLR family pyrin domain containing 3 (nlrp3), interleukin 1 beta (il1ß), interleukin 6 cytokine family signal transducer (il6st) but upregulated transforming growth factor beta 1 (tgfß1) and heat shock 70 kDa protein (hsp70) expression. Moreover, berberine at both levels maintained the intestinal structural integrity and significantly improved gap junction gamma-1 (gjc1) mRNA level compared to the Cu group (P < 0.05). Based on 16S rDNA sequencing, the richness and diversity of intestinal microbiota in different groups were not significantly influenced. Berberine reduced the Firmicutes/Bacteroidota ratio and stifled the growth of some specific pathogenic bacteria such as Pseudomonas, Citrobacter, and Acinetobacter, while boosting the richness of potential probiotic bacteria, including Roseomonas and Reyranella compared with the Cu group. In conclusion, berberine showed significant protective effects against Cu2+-induced intestinal oxidative stress, inflammation response, and microbiota disturbance in freshwater grouper.

Effects of Curcumin on Oxidative Stress and Ferroptosis in Acute Ammonia Stress-Induced Liver Injury in Gibel Carp (Carassius gibelio).

This study investigated the potential role of curcumin (CUR) in preventing oxidative stress and ferroptosis induced by ammonia exposure in gibel carp. Experimental fish (initial weight: 11.22 ± 0.10 g, n = 150) were fed diets supplemented with or without 0.5% CUR for 56 days, followed by a 24 h ammonia (32.5 mg/L) exposure. Liver damages (aspartate aminotransferase (AST), alanine aminotransferase (ALT), adenosine deaminase (ADA), and alkaline phosphatase (ALP)) and oxidative stress enzyme activities (reactive oxygen species (ROS), malondialdehyde (MDA); and the content of antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GPx)) were induced by ammonia stress. The antioxidant capacity was decreased, as indicated by inhibited gene expression of nuclear factor erythroid 2-related factor 2 (nrf2), heme oxygenase-1 (ho-1), catalase (cat), and sod. Ferroptosis was induced by ammonia stress, as suggested by upregulated mRNA levels of nuclear receptor coactivator 4 (ncoa4), transferrin receptor 1 (tfr1), and iron-responsive element-binding protein 2 (ireb2), and downregulated expression of glutathione peroxidase 4 (gpx4), ferroportin (fpn), and ferritin heavy chain 1 (fth1). In addition, both mRNA and protein levels of ferroptosis markers acyl-CoA synthetase long-chain family member 4 (ACSL4) and prostaglandin-endoperoxide synthase 2 (PTGS2) were upregulated, while cystine/glutamate antiporter (SLC7A11) was downregulated. However, liver injury and ferroptosis in fish induced by ammonia could be attenuated by CUR. Collectively, these findings demonstrate that CUR ameliorates oxidative stress and attenuates ammonia stress-induced ferroptosis. This study provides a new perspective on potential preventive strategies against ammonia stress in gibel carp by dietary CUR.

Complimentary effect of exogenous enzymes, essential amino acids and essential fatty acids supplemented de-oiled rice bran (DORB) based diets on hematology, liver and intestinal histoarchitecture in Labeo rohita.

A 60-day feeding trial was conducted to study the hematology, liver, and intestinal histoarchitecture of Labeo rohita fed with a combination of exogenous enzymes, essential amino acids, and essential fatty acids to DORB (De-oiled rice bran) based diets. Three treatments viz., T1 [DORB + phytase and xylanase (0.01% each)], T2 [DORB + phytase (0.01%) + xylanase (0.01%) + L-lysine(1.4%) + L-methionine (0.4%) + EPA and DHA (0.5%)] and T3 [DORB + phytase (0.01%), xylanase and cellulase (0.075%) + L-lysine (1.4%) +L-methionine (0.4%) + EPA and DHA (0.5%)] were used in the present study. Serum total protein, albumin content and A/G ratio varied significantly (p < 0.05) among groups. Globulin content did not vary significantly among groups (p ≥ 0.05). The Hb content, RBC and MCV count varied significantly (p < 0.05) whereas MCH, MCHC content, WBC and lymphocyte count did not vary significantly among groups (p > 0.05). The liver and intestine examination revealed no visible alteration and showed normal histo-architecture. Based on the finding it is concluded that DORB supplemented with exogenous enzymes, essential amino acids and essential fatty acids with phytase (0.01%), xylanase and cellulase (0.075%), L-lysine (1.4%), DL-methionine (0.4%) and EPA and DHA (0.5%) improves the health of L. rohita.

Effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Amur minnow (Rhynchocypris lagowskii).

Probiotics are widely used in aquaculture. This article aims to study the effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Rhynchocypris lagowskii. B. amyloliquefaciens LSG2-8 were added to R. lagowskii basal diets (CK) as additives at four concentrations: 1.0 × 106 (D-6), 1.0 × 107 (D-7), 1.0 × 108 (D-8) and 1.0 × 109 (D-9) CFU g-1 by dry weight of basal diet. After a 56-day feeding experiment, the activities of intestinal digestive enzymes and immunity-related enzymes of R. lagowskii on group D-6, D-7, D-8 and D-9 diet were significantly higher than the control (P < 0.05). In molecular experiments, the authors found that the levels of TGF-ß mRNA, IL-10 mRNA, ZO-1 mRNA and claudin-3 mRNA in group D-8 R. lagowskii were significantly higher (P < 0.05) than those of the control and other groups. Furthermore, the levels of IL-1ß and IL-8 mRNA of R. lagowskii on group D-6, D-7, D-8 and D-9 diet were significantly lower than those of the control (P < 0.05). In addition, the authors found that B. amyloliquefaciens LSG2-8 can regulate the intestinal flora balance and improve the intestinal structure of R. lagowskii. In conclusion, B. amyloliquefaciens LSG2-8 can improve the intestinal barrier function of R. lagowskii and can be used as a feed additive in aquaculture.

Comprehensive GIS based risk surveillance of organochlorine pesticides (OCPs) in edible fish species of River Chenab, Pakistan.

The present study was conducted to evaluate Carcinogenic (TR) and non-carcinogenic (THQ) human health risk of organochlorine pesticides (OCPs) in three edible fish species (Labeo boga, Channa marulius and Wallago attu) of River Chenab, Pakistan using USEPA human health risk assessment model. Holistic GIS (Geographic information system) based Geo-Statistical approach has been employed for the first time in River Chenab, Pakistan to categorize contaminated risk zones of OCPs based on single pollution index. The ∑OCPs concentrations in fish species were ranged from 5.09 to 414 ng/g with the prevalence of dieldrin. Results of single pollution index of DDE, aldrin, dieldrin and ∑endosulfan revealed River Chenab as polluted and risk zone area. Distribution pattern assessed significantly higher (p < 0.05) concentrations of OCPs in downstream area suggesting substantial pollution of surrounded industrial region. The human health risk assessment depicted no harmful non-carcinogenic (THQ) risk except for ΣOCPs concentration of C. marulius. Significant carcinogenic (TR) health risk exhibited by all examined OCPs from maximum of the studied sites. Therefore, the high carcinogenic human health risk had highlighted an immediate removal of continuous disposal of OCPs in the River Chenab.

Ameliorative role of dietary acidifier potassium formate on growth metrics, blood chemistry, gut health and well-being indices of rohu, Labeo rohita fingerlings.

Organic acids and their derivatives have been attributed to growth and well-being improvement in fish when supplemented in their diets. Therefore, this study was conducted to evaluate the ameliorative role of potassium formate (PF) in rohu Labeo rohita fingerlings. A total of 240 healthy rohu fingerlings (9.0 ± 0.5 g ± SE) were randomly divided into four equal groups in triplicates. Fish were fed with isonitrogenous feeds: PF10 (10 g PF/kg), PF20 (20 g PF/kg) and PF30 (30 g PF/kg). Feed without PF supplementation served as control. The results indicated that the specific growth rate (SGR) and feed conversion ratio (FCR) were significantly (p<0.05) higher in PF10. Total serum globulin content was found significantly (p<0.05) elevated in PF10 after the bacterial challenge. Non-specific lysozyme activity was significantly higher (p<0.05) after the challenge. The digestive protease enzyme activity was significantly (p<0.05) improved in PF10 treatment. Additionally, the digestive morphology of the treated fish was seen to be improved. Greater villus area, increased villus number, reduced lumen space in the hindgut, reduced vacuolation in mucosal folds and proliferation of goblet cells-like changes were observed in the PF-supplemented fish. Significantly (p<0.05), a higher relative percentage of survival (RPS) was observed in PF10 and PF20 treatments. The study revealed that the dietary supplementation of rohu fingerlings with lower levels of potassium formate could enhance the nutritional efficiency and physiological activities of rohu fingerlings. This study serves as a baseline for future research on the application of formic acid derivatives and other acidifiers in carp culture.

Dietary supplementation with Lycium barbarum polysaccharides conducive to maintaining the health of Luciobarbus capito via the enhancement of enzyme activities and the modulation of gut microbiota.

Lycium barbarum polysaccharide (LBP) is the main active component of Lycium barbarum (L. barbarum), which has important medicinal and nutritional value. However, the effect of LBP treatment on Luciobarbus capito (L. capito) still remains unknown. Given this, the current work aims to probe the underlying effect of different levels of LBP treatment (i.e. 0.10, 0.50 and 1.00 g/L) on L. capito in the context of enzymatic activity analysis, histological observations and gut microbiota analysis. Compared with control group, the activities of hepatic antioxidant enzymes, intestinal digestive enzymes and hepatic immune enzyme were found to be significantly increased after 0.10 g/L LBP and 0.50 g/L LBP treatment (P < 0.05). This result indicated that moderate levels of LBP treatment could dramatically enhance the immunity and antioxidant capacity of L. capito. Furthermore, the compositional structures of the gut microbiota in L. capito were found to be greatly shaped after LBP treatment, whereas the diversity and abundance of the gut microbiota were only found to be slightly changed (P > 0.05). No significant changes were screened in the morphologic structures of gut constructions. This work would provide theoretical and experimental basis for future application of LBP as supplement in the culture process of the farmed fish.

The effects of the water-soluble fractions of crude oil on liver and kidney tissues of Caspian Kutum juveniles, Rutilus frisii.

The lethal and histopathological impacts of crude oil's Water-Soluble Fraction (WSF) on the liver and kidney tissues of juvenile Rutilus frisii were investigated. The LC50 96 h of WSF was calculated at 33.95 ppm. Fish exposed to two concentrations (0.1 LC50 and LC50) of WSF and control for 24 and 96 h were used for histopathological studies. Tissues in the control group and 0.1 LC50-24 h were healthy, and no specific damages were observed. With increasing exposure time (96 h) and concentration (LC50), damages' type, frequency, and intensity gradually increased. Cloudy swelling, loss of cell boundary, nuclei deformation, and congestion of blood vessels were found in the liver, enlarged glomeruli, reduced Bowman's space, and occlusion of the tubular lumen, were found in the kidney. It is demonstrated that the WSF of crude oil can cause severe damage to the tissues of juvenile Kutum, depending on the exposure concentration.

Effect of ajwain (Trachyspermum ammi) extract and gamma irradiation on the shelf-life extension of rohu (Labeo rohita) and seer (Scomberomorus guttatus) fish steaks during chilled storage.

Fishes are highly perishable, mainly stored and transported under frozen condition; however, they are mainly preferred as fresh or in chilled form for consumption because frozen storage compromises the texture quality and other sensory attributes. Shelf-life enhancement of rohu and seer fish steaks was studied using combination of ajwain extract (various concentrations) and γ-irradiation (various doses) under chilled storage (4 °C). These were analyzed periodically by microbiological, sensory, color and biochemical analyses during storage. Gas chromatography - mass spectrometry (GC-MS) analysis showed thymol as major component. High performance liquid chromatography (HPLC) analysis showed the presence of nine phenolic compounds including thymol in ajwain extract. The best result was achieved when samples were dipped in 10 % ajwain extract with 2 kGy gamma irradiation dose. An extended shelf-life of 5 and 10 days in case of rohu and seer fish steaks were attained respectively using this combination. These results were confirmed by microbial, biochemical and sensory analyses. The present study thus promises potential application of the above protocol in fishery industry for good quality of fish and commercial benefits.