Search

Setting up nutritional requirements with high-quality, time-saving marine finfish larvae is a big issue for increasing aquaculture profit. In the current study, we evaluated the nutritional value of two enrichment diets [DHA oil emulsion-enriched Artemia (Art-DHA-Selco) and mixed algae-enriched Artemia (Art-MA)] and two-timing protocol (2 & 24 h) for serving European Sea bass. Larval growth performance and survival percentage, as well as biochemical compositions of the enriched Artemia and for the fed larvae after 25 rearing days, were determined. The results revealed that survival percentage (S%), feed conversion ratio (FCR), and protein efficiency ratio (PER) was insignificantly affected by the two factors (diets and time) or the interaction between them. Otherwise, growth in terms of final body weight (FBW), specific growth rate (SGR) as well as productive protein value (PPV) differed significantly at (P≤ 0.01) among treatments in both factors. Concerning biochemical analysis, the highest protein value was recorded in Art-MA at 24 h. In contrast, lipid and carbohydrate levels were considerably higher in Art-MA 2 h than in the Art-DHA. That decrease in protein content, FBW, and SGR in the 2 h period in the MA treatment may attribute to the smaller size of the Artemia metanauplii in the 2 h than those after 24 h. That can be overcome by starting with Artemia metanauplii at the end with Instar II before enrichment process so that the size is big enough to give better results. The results revealed that PUFAs percentages were significantly highest especially EPA percentage in the enriched Art-MA 2 h followed by its correspondence Art-MA at 24 h compared with Art-DHA or un-enriched ones. Otherwise, the fatty acid composition (FA) of post-larvae surpassed greatly in EPA and n3/n6 ratios as diet reflection in the algal short-term duration. Based on the results and the documented drawbacks of DHA-Selco, the authors recommended using mixed algae in the enrichment protocol for feeding larval stages over the short term.

Large quantities of sludge are produced during water treatment processes. Recently, sludge has been treated as waste and disposed of in landfills, which increases the environmental burdens and the operational cost. Therefore, sludge reuse has become a significant environmental issue. In this study, adsorption of copper ions (Cu2+) onto calcined sludge was investigated under various operational conditions (with varying temperature, Cu2+initial concentration, pH, and sludge dosage). The prepared sludge material was characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and Brunauer-Emmett-Teller (BET) surface area. The sorption capacity of sludge was directly proportional to the initial Cu2+concentration and inversely proportional to the sludge dosage. The optimum operational pH and solution temperature were 6.6 and 80°C, respectively. The experimental results followed a Langmuir isotherm and pseudo-first-order adsorption kinetics. Thermodynamic parameters such as activation energy, change in free energy, enthalpy, and entropy were calculated. Thermodynamic analyses indicated that the sorption of copper ions onto the calcined sludge was driven by a physical adsorption process. The prepared sludge was proven to be an excellent adsorbent material for the removal of Cu2+from an aqueous solution under optimum conditions.

Adding medicinal herbs to aquafeed is recommended for feasible aquaculture activity. This study tested for 90 days the effect of dietary sage (Salvia officinalisL.) on the growth performance, feed efficacy, blood indices, non-specific immunity, and intestinal microbiota of European sea bass (Dicentrarchus labrax; n = 300 fish). Fish with an initial weight of 12 ± 0.1 g/fish were distributed in five treatments and fed sage at 0, 2, 4, 6, and 8 g/kg. Dietary sage at 2 g/kg diet improved the growth, feed consumption, and growth hormone secretion in European sea bass. The blood parameters in European sea bass fed on experimental diets showed normal levels for healthy fish. Significantly higher lysozyme and phagocytic activities were recorded with sage supplement at the 4 g/kg diet compared to other groups. Regarding overall bacterial count, fish given a sage-free diet (the control) showed more significant microbiota numbers, Vibrio, Escherichia coli, and acid-fermentative bacteria. Remarkably, fish fed on diets fortified with sage displayed lower records of the total bacterial count, Vibrio, and Escherichia colithan the control. Moreover, fish fed a diet enriched with high levels of sage (6 or 8 g/kg) showed increased acid-fermentative bacteria. The regression analysis showed that the optimum quantity of sage at 3.6 – 4.1 g/kg diet is recommended based on the weight gain, specific growth rate (SGR), phagocytic activity, feed conversion ratio (FCR), and lysozyme activity. In conclusion, the dietary incorporation of sage (2 – 4 g/ kg diet) enhanced growth, feed efficacy, blood indices, non-specific immune responses, and sustained healthier gut flora in European sea bass.

An 84-day growing trial was conducted to evaluate Liza ramada'sperformance and health. Five treatments (3 replicates) were tested using anexperimental diet (ED) supplemented with rosemary oil (RO) or RO and amylase-lipase (AL) enzymes as follows; (T1) fish-fed ED with no additives “control”; (T2) fish fed ED containing 0.5kg ton-1RO; (T3) fish fed ED containing 0.5kg RO and 0.917kg AL ton-1; (T4) fish fed ED containing 1 kg ton-1RO; and (T5) fish fed ED containing 1 kg RO and 0.917kg AL ton-1. A total of 150 Liza ramadafish (7.30±0.01 g/fish) were housed in 15 hapas (10 fish/hapa) and fed tested diets twice daily at 4-3% of body weight. Findings revealed that fish that received RO and RO+AL supplemented diets had lower NH3 levels and higher survival rates (24.32, 51.34, 37.83, and 54.05%) in groups T2, T3, T4, and T5, respectively when compared to the control. Furthermore, improvements in FW, WG, SGR, and FCR were recorded for fish-fed supplemented diets with better values at T5. Moreover, liver enzyme activity, kidney function indices, and intestinal histomorphometric measurements were improved in fish-fed RO+AL treated diets. The recommended treatment is T5 (1 kg RO and 0.917 kg AL ton-1).

A 30-day feeding trial was performed to assess the potential of the dietary supplementation of Coenzyme Q10 (CoQ10) and lipoic acid on acclimatized European seabass larvae with a preliminary weight and length of 2.7 mg and 12.42 mm (25 dph = days post-hatching). Seven experimental groups were fed on the basal micro-diet (56 % crude protein and 13 % crude lipid) without any supplement in the control group or with the addition of CoQ10 at levels of 5, 10, and 15 mg/kg or α-lipoic acid at levels of 50, 100, and 150 mg/kg, respectively. Larvae fed on a diet enriched with CoQ10 at levels of 5 and 10 mg/kg showed the highest values for final weight, weight gain, specific growth rate (SGR), the protein efficiency ratio (PER), and the lowest value for feed conversion ratio (FCR) as well as no morphological or histological abnormalities. Also, the group fed a diet supplemented with CoQ10 at 5 mg/kg gave the highest values for final length and survival. The survival rate ranged from 54.59 % to 79.82 % and the lowest rate was in the group fed a diet enhanced with lipoic acid at 150 mg/kg. Meanwhile, the lowest records for final weight, weight gain, protein efficiency ratio, and the presence of morphological and histological abnormalities were in groups fed on the control diet and with high levels of lipoic acids (100 and 150 mg/kg). Moreover, all lipoic acid groups showed deleterious signs in the histological structure of the intestine and liver. However, significantly lower values of catalase (CAT) and glutathione peroxidase (GPx) were found in the fish group fed on the basal diet, while the peak values were in groups fed on diets fortified with CoQ10 at 5 and 10 mg/kg. In addition, larvae fed CoQ10 at levels of 5 or 10 mg/kg performed better in terms of CAT and GPx activities than that fed lipoic acid at levels of 100 or 150 mg/kg. Furthermore, the control group displayed lower levels of insulin-like growth factor 1 (IGF-1), CAT, and GPx -related gene expressions while considerable upregulations of IGF-1 and GPx were noted in larvae groups fed on diets improved with CoQ10 at levels of 5 or 10 mg/kg and lipoic acid at 50 mg/kg compared to the others. Also, upregulations in CAT were found with CoQ10 at levels of 5 or 10 mg/kg compared to their counterparts in the other groups. In conclusion, dietary CoQ10 at 5 or 10 mg/kg improves the performance and well-being of European seabass.