Bentonite-supplemented diets improved fish performance ammonia excretion haemato-biochemical analyses immunity antioxidants and histological characteristics of European seabass Dicentrarchus labrax.

The purpose of this research was to examine the potential effects of bentonite (BN) supplemented diets on growth, feed utilization, blood biochemistry, and histomorphology of Dicentrarchus labrax. Six treatments in triplicate were tested: B0, B0.5, B1.0, B1.5, B3.0, and B4.5, which represented fish groups fed diets supplemented with 0, 0.5, 1, 1.5, 3, and 4.5% BN, respectively. For 84 days, juveniles' seabass (initial weight = 32.73 g) were fed diets containing 46% protein, three times daily at 3% of body weight. With a 5% daily water exchange, underground seawater (32 ppt) was used. Findings revealed significant improvements in water quality (TAN and NH3), growth (FW, WG and SGR) and feed utilization (FCR, PER and PPV) in fish fed BN-supplemented diets, with the best values in favor of the B1.5 group. Additional enhancements in kidney function indicators (urea and uric acid) and liver enzymes were observed in fish of the BN-treated groups along with a decrease in cholesterol level in the B1.5 group. Further improvements in fish innate immunity (hemoglobin, red blood cells, glucose, total protein, globulin, and immunoglobulin IgM), antioxidant activity (total antioxidative capacity and catalase), and decreased cortisol levels in fish of the BN-treated groups. Histological examinations of the anterior and posterior intestines and liver in groups B1.5 and B3 revealed the healthiest organs. This study recommends BN at a concentration of 1.5% as a feed additive in the Dicentrarchus labrax diet.

Natural zeolite for heavy metal, ammonia removal, and physiological responses in European sea bass (Dicentrarchus labrax) juveniles tanks with different densities.

The present study aims to investigate the influence of zeolite usage and stocking densities on various parameters, including ammonia removal from water, accumulation of heavy metals in fish organs, water quality, growth performance, feed efficiency, muscle composition, as well as hematological and biochemical parameters in European seabass (Dicentrarchus labrax) over a 90-day duration. A total of 2400 D. labrax with an initial weight of 9.83 ± 2.02 g and initial length of 9.37 ± 0.32 cm were distributed among 24 tanks. The research involved six distinct treatment groups, with two different zeolite levels (0 and 15 ppt) and three stocking density levels (50, 100, and 150 fish/m3), each replicated four times. The results of the research demonstrate a statistically significant improvement (p < 0.05) in water quality measures with the introduction of zeolite. The successful implementation of this amendment mitigated the adverse effects of fish density on water quality parameters. Higher stocking density negatively impacted European sea bass growth, feed utilization, and hemato-biochemical indicators. Zeolite use effectively alleviated these adverse effects, particularly on performance, feed utilization, hematological, and biochemical parameters. The study's results indicate that the utilization of zeolite has shown to be efficacious in mitigating the accumulation of heavy metals in both water and fish organs, while concurrently augmenting fish attributes. However, the increase in density led to a significant decrease in the accumulation of heavy metals in both water and fish organs. The present study highlights the capacity of natural zeolites to mitigate the negative consequences associated with water quality concerns. The efficiency of these zeolites in limiting the accessibility of heavy metals in polluted water is shown, hence minimizing their accumulation in fish organs. In addition, the improvement of fish performance has the capacity to have a beneficial influence on both the well-being and efficiency of fish in aquaculture. Additional research is essential to fully understand the complex molecular pathways involved in utilizing natural zeolite under different fish densities.

Dietary Wood and Activated Charcoal Improved Ammonium Removal, Heavy Metals Detoxification, Growth Performance, Blood Biochemistry, Carcass Traits, and Histopathology of European Seabass.

A 120-day growth trial was completed to assess rearing water quality and fish performance in terms of growth, feed efficacy, digestive enzymes, immunity, and antioxidant activity of seabass fed an experimental diet (ED) supplemented with commercial wood charcoal (WC) and activated wood charcoal (AC). Three levels (0, 10, and 20 g) of WC and AC were administered, representing five treatments: control (CD) fish-fed ED without additives, (WC-1) fish-fed ED containing 10 g kg-1 WC, (WC-2) fish-fed ED containing 20 g kg-1 WC, (AC-1) fish-fed ED containing 10 g kg-1 AC, and (AC-2) fish-fed ED containing 20 g kg-1 AC. Three hundred fish (60.12 ± 0.20 g/fish) were stocked in 15 cement tanks (4.0 m × 2.0 m × 1.2 m, water volume 5 m3 each) at 20 fish/tank and a daily feed ration of 3% of body weight. Results revealed significant improvements with increased growth variables (final weight, weight gain, and specific growth rate), decreased FCR, and decreased ammonia levels and heavy metals (Cu, Cd, Fe, Mn, and Zn) content in rearing water, muscle, and liver with fish fed WC and AC supplemented diets. Furthermore, considerable improvements in digestive enzymes, immunity, and antioxidant activity, with enhanced kidneys, liver, intestines, gills, and spleen. Fish fed the WC-1 diet had a higher final weight (171.90 g), better FCR (1.25), and improved internal organs than the other groups.