Enhancing farmed striped catfish (Pangasianodon hypophthalmus) robustness through dietary ß-glucan.

ß-glucan is a well-documented feed additive for its potent immunostimulatory properties in many farmed fish species. This study examined how it can also be a promising growth promoter, modulate antioxidant enzyme activities, and act as an anti-stress agent in striped catfish (Pangasianodon hypophthalmus). A 12-week feeding experiment was untaken to determine the effects of dietary ß-glucan supplementation at graded levels (0, 0.5, 1.0, and 1.5 g kg-1). Measured indicators suggest that a dietary inclusion level of 1.5 g kg-1 ß-glucan gave the highest positive responses: weight gain (120.10 g fish-1), survival (98.30%), and lower FCR (1.70) (P<0.05). Whole body proximate analysis had only revealed that crude protein was significantly affected by the dietary inclusion of ß-glucan (P<0.05), with the highest protein content (19.70%) being in fish that were fed with 1.5 g kg-1 ß-glucan. Although other inclusion levels (i.e., 0.5 and 1 g kg-1) of ß-glucan did not enhance body protein content (P>0.05). The assessment of fatty acid composition in muscle, liver, and adipose tissues showed modifications with the inclusion of ß-glucan. Antioxidative-related enzyme activities (inc. catalase, glutathione peroxidase, and superoxide dismutase) that were measured in the liver had higher levels when fed with ß-glucan inclusion diets (P<0.05). Following the feed trial, fish were subjected to crowding stress treatment. It was subsequently found that catfish fed with ß-glucan-based diet groups had lower levels of blood stress-related indicators compared to the control group with no dietary ß-glucan. The use of 1.5 g kg-1 of dietary ß-glucan resulted in the lowest measured levels of cortisol (43.13 ng mL-1) and glucose (50.16 mg dL-1). This study has demonstrated that the dietary inclusion of ß-glucan can have functional benefits beyond the immunological enhancements in striped catfish. Furthermore, its use can increase production levels and mitigate the stress associated with intensive farming practices.

Feasibility of replacing fish oil with sunflower oil on the growth, body composition, fatty acid profile, antioxidant activity, stress response, and blood biomarkers of Labeo rohita.

A 90-day study was conducted to investigate the effects of substituting sunflower oil (SFO) for fish oil (FO) on various parameters in Labeo rohita (initial weight 18.21 ± 0.22 g). Five experimental diets with different levels of SFO (up to 7%) substitution for FO (0%, 25%, 50%, 75%, and 100%) were formulated, ensuring equal levels of nitrogen and lipids. The results indicated that even with 100% substitution of SFO with FO, there were no significant differences (P>0.05) were observed in growth performance. The survival rate (SR), hepato-somatic index (HSI), and viscero-somatic index (VSI) as well as whole-body composition were also nonsignificant by SFO substitution. However, the fatty acid profiles in both muscle and liver were influenced (P<0.05) by dietary substitution. Saturated fats (SFA) decreased, while monounsaturated fats (MUFA), and linoleic acid (LA) increased (P<0.05). On the other hand, the contribution of linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) decreased (P<0.05) as the amount of SFO in the diet increased. Hematology parameters, including red blood cells (RBCs), hemoglobin (Hb), and hematocrit (Hct), were not affected. Globulin (GLO) levels decreased significantly (P<0.05), while alanine transaminase (ALT) and aspartate transaminase (AST) activity showed nonsignificant increases (P>0.05). Total protein (TP) increased (P<0.05) at 100% SFO inclusion in the diet, and albumin (ALB) levels increased (P<0.05) at 75% and 100% SFO inclusion in the diet. Cholesterol (CHOL), triacylglycerol (TG), and high-density lipids (HDL) were not significantly affected (P>0.05), while low-density lipids (LDL) were significantly increased (P<0.05) compared to the control group. Cortisol (CORT) and glucose (GLU) levels showed nonsignificant (P>0.05) changes. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities in the liver and serum were not significantly (P>0.05) affected, while malondialdehyde (MDA) status was significantly (P<0.05) reduced. In conclusion, the fatty acid profile of the muscle and liver of fish was modified by the diets, and FO can be substituted with SFO up to 100% for L. rohita, which is beneficial for growth and immunity while marinating the lipid contents in fish. Our study revealed that fully replacing fish oil with SFO shows promise in fully replacing FO without compromising the growth and overall health status of the fish.

Administration of vitamin E and C enhances immunological and biochemical responses against toxicity of silver nanoparticles in grass carp (Ctenopharyngodon idella).

The aim of the current study was to evaluate the toxic effect of silver nanoparticles (Ag-NPs) on biochemical biomarkers, immune responses, and the curative potential effects of vitamin C and E on grass carp. Fish (n = 420) with an average initial body weight of 8.045 ± 0.13 g were shifted to glass aquaria (36 x 18 x 18 inches, filled with 160-L tap water) in triplicates. Aquaria were randomly designated as A, B, C, D with alone Ag-NPs (Control (0), 0.25, 0.50, 0.75 mg/L) and E, F, G with Ag-NPs + Vit. C + Vit. E (0.25+0.25+0.25, 0.50+0.50+0.50, 0.75+0.75+0.75 mg/L). NPs particles were administrated viz, oral and intravenous routes for 7 days. The results indicated that both routes had non-significant effect, but levels of Ag-NPs had significant effect. Treatments C, D and G showed significant decrease in levels of RBC, HGB and HCT except for WBC and NEUT levels, which significantly increased. ALT, ALP, AST, urea, and creatinine showed significant increase in activity in the C, D, and G groups. CAT, SOD decreased significantly in all Ag-NPs alone groups, while significantly increased with vitamin E and C. LYZ, TP, ALB, GLB showed significant low activity in the B, C, and D groups while significantly high activity in the E, F, and G groups. Cortisol, glucose and triglycerides showed significant increase in the B, C, and D groups, while E, F, and G groups showed significant low levels of triglycerides, COR, and GLU. Cholesterol level was same across all treatment groups. In conclusion, vitamin E and C as powerful antioxidants protect the fish against Ag-NPs except high dose level of 0.75mg/L, while 0.25mg/L of Ag-NPs was presumably safe for C. idella.

The influence of dietary protein concentration on digestive enzyme activities, growth, and body composition in juvenile bullseye snakehead (Channa marulius).

The bullseye snakehead (Channa marulius) is considered as an affordable and robust freshwater fish for farming in Asia. However, there is limited knowledge on the species' full nutritional requirements to date with extensive gaps in our knowledge and particularly in precision aspects of protein requirements. Therefore, a three-month feeding trial was conducted under semi-intensive farming conditions to determine the protein requirement of bullseye snakehead using test diets containing 40 (P40), 45 (P45), 50 (P50), and 55% (P55) crude protein levels. The growth performance results revealed that the 55% dietary protein group (P55) had the highest final mean weight (14.09 g fish-1), and net weight gain (12.82 g fish-1). When compared to other dietary treatments, the final weight (R2 = 0.921), and weight gain (R2 = 0.913), displayed a linear increasing trend as dietary protein is raised. The lowest FCR was observed in 50% (1.94±0.01) and 55% (1.97±0.01) CP diet groups compared to dietary treatments. Further analysis has shown that the body protein content also significantly increased as dietary protein was raised to 55%. Although, a reverse trend was found in body lipid levels with increasing protein in the diet. The incremental dietary protein also elevated proximal intestinal protease activity but decreased amylase and lipase activity. The overall essential and non-essential amino acids levels of snakehead fillet muscle reflected an increase in dietary protein. Overall, this study has shown that the fish fed a diet with 55% crude protein attained the highest growth performance and nutrient profile of the whole fish when compared to other dietary treatments tested. It would appear we did not obtain the maximum potential for growth under the present experimental conditions due to the upper protein constraint of 55% in the diet. Further quantitative studies are suggested.

Effects of dietary Hyssop, Hyssopus officinalis, extract on physiological and antioxidant responses of rainbow trout, Oncorhynchus mykiss, juveniles to thermal stress.

The present study aimed at assessing the effects of dietary Hyssop, Hyssopus officinalis, extract on rainbow trout, Oncorhynchus mykiss, responses to thermal stress. The juveniles (69.8 ± 0.38 g) were stocked in 12 through-flow tanks at a density of 12 fish per tank. Methanolic extract of Hyssop (HME) was added to diet at 0, 100, 250, and 500 mg/kg and the fish were fed (3% of biomass) over a 70-d period: 62 d at 13.3 ± 0.08°C and 7 d at 21-22°C. At the end of the trial, the plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), triiodothyronine (T3), thyroxin (T4), cortisol, glucose, lactate, total antioxidant capacity (TAC), ascorbate, and the gill glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), and malondialdehyde (MDA). The results showed that HME had no significant effects on fish growth performance, survival, and feed efficiency. Dietary 250 mg/kg HME significantly decreased plasma ALT activity (P < 0.001), but showed no significant effects on plasma AST) (P = 0.106) activity, T3 (P = 0.992), and T4 (P = 0.070) levels. Thermal stress significantly (P < 0.001) increased plasma ALT and AST activities, but lowered plasma T3 and T4 levels. Dietary HME and thermal stress had interaction effects on plasma cortisol (P < 0.001), glucose (P = 0.007), lactate (P = 0.010), LDH (P = 0.005), TAC (P = 0.038), ascorbate (P < 0.001), and the gill GPx (P = 0.001), GR (P < 0.001), GST (P < 0.001), and MDA (P = 0.001). Thermal stress significantly increased plasma cortisol, glucose, lactate, and LDH, the gill GPX, GR, and GST, but dietary HME supplementation significantly reduced such elevations, particularly at 250 mg/kg level. Dietary HME significantly increased plasma TAC before the thermal stress and mitigated the stress-induced decreased in TAC, particularly at 250 mg/kg level. Dietary HME significantly decreased the gill MDA before and after the thermal stress, and lowest MDA was observed in 250 mg/kg HME level. Based on the present results, 250 mg/kg HME is recommended as suitable dose to improve antioxidative responses and hepatoprotection in rainbow trout under heat stress.

Peritoneal Dialysate Glucose Load and Systemic Glucose Metabolism in Non-Diabetics: Results from the GLOBAL Fluid Cohort Study.

BACKGROUND AND OBJECTIVES: Glucose control is a significant predictor of mortality in diabetic peritoneal dialysis (PD) patients. During PD, the local toxic effects of intra-peritoneal glucose are well recognized, but despite large amounts of glucose being absorbed, the systemic effects of this in non-diabetic patients are not clear. We sought to clarify whether dialysate glucose has an effect upon systemic glucose metabolism. METHODS AND MATERIALS: We analysed the Global Fluid Study cohort, a prospective, observational cohort study initiated in 2002. A subset of 10 centres from 3 countries with high data quality were selected (368 incident and 272 prevalent non-diabetic patients), with multilevel, multivariable analysis of the reciprocal of random glucose levels, and a stratified-by-centre Cox survival analysis. RESULTS: The median follow up was 5.6 and 6.4 years respectively in incident and prevalent patients. On multivariate analysis, serum glucose increased with age (ß = -0.007, 95%CI -0.010, -0.004) and decreased with higher serum sodium (ß = 0.002, 95%CI 0.0005, 0.003) in incident patients and increased with dialysate glucose (ß = -0.0002, 95%CI -0.0004, -0.00006) in prevalent patients. Levels suggested undiagnosed diabetes in 5.4% of prevalent patients. Glucose levels predicted death in unadjusted analyses of both incident and prevalent groups but in an adjusted survival analysis they did not (for random glucose 6-10 compared with <6, Incident group HR 0.92, 95%CI 0.58, 1.46, Prevalent group HR 1.42, 95%CI 0.86, 2.34). CONCLUSIONS: In prevalent non-diabetic patients, random glucose levels at a diabetic level are under-recognised and increase with dialysate glucose load. Random glucose levels predict mortality in unadjusted analyses, but this association has not been proven in adjusted analyses.