Search

This study reports on the synthesis and characterization of ZnO–Ag@AgBr/SBA-15 composites using natural halloysite clay from Yenbai Province, Vietnam, as a silica aluminum source.

The paper reported synthesizing 1,4-dihydropyridine (1,4-DHP) from β-ketoester, aromatic aldehyde, and ammonium acetate via a two-step, using heterogeneous catalyst Amberlyst-15 in high yields at room temperature. The method was applied to synthesize some 1,4-DHP derivatives. Moreover, the catalyst was reused at least five times without loss of catalytic activity under eco-friendly conditions.

In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a global pandemic. In Vietnam, the incidence rate started climbing in May 2021, reaching an all-time high of 9,000 cases per day, and is projected to increase even further. Direct patient contact, as has always been the case in conventional medical practice, now constitutes significant transmission risk during the height of COVID-19. Healthcare workers, while accounting for a minor proportion of the population, are two to three times more likely to contract COVID-19, especially those who provide outpatient care or home-based service. The pandemic has led to a significant increase in the adoption of telemedicine, as hospitals are overwhelmed with critically ill patients, demand for healthcare soars, and transmission risk remains serious. With appropriate attention and further advancement of Vietnam's telehealth infrastructure, telemedicine will become an indispensable weapon to combat COVID-19 and an important modality of medical care during and after the pandemic.

The study was executed to find out the potential effects spent coffee ground (SCG) on Nile tilapia's skin mucosal and serum immunities, disease prevention, and growth rate reared in a biofloc system. Nile tilapia fingerlings (average weight 15.25 ± 0.07 g) were disseminated into 15 aquaria (150 L tank−1) at a density of 20 fish per aquarium and treated five diets: SCG1 (control), SCG2 (10 g kg−1), SCG3 (20 g kg−1), SCG4 (40 g kg−1), and SCG5 (80 g kg−1) for eight weeks. A Completely Randomized Design (CRD) with three replications was applied. Growth rate, skin mucus, and serum immunities were quantified every 4 weeks; whereas the challenge study was conducted at the termination of the feeding trial. The outputs indicated that dietary incorporation of SCG give rise to the enhancement of SGR and FCR in comparison with the control, with best levels noted in fish fed SCG2 diet. Similarly, significant enhancements in skin mucosal and serum immunities were revealed in fish treated SCG2 over the control and other SCG diets. Likewise, higher survival rates against Streptococcus agalactiae were displayed in fish fed SCG, with the maximum level displayed in the fish treated SCG2. In conclusion, dietary supplementation of SCG2 (10 g kg−1) can be potential used as immunostimulants in tilapia aquaculture.

The supplementation of fish diets with phytogenics can increase growth performance and can modulate immune system response. European perch Perca fluviatilis (initial weight 25.0 ± 0.4 g) were fed a diet including 0 (Control), 10 (G10), 20 (G20), and 30 (G30) g kg−1 garlic powder. No significant difference in the growth parameters and somatic indices were observed. Significantly higher fat digestibility was observed in G10 and G30 diets compared to in the control and G20 diets(p &lt, 0.05). Significantly greater red blood cell and white blood cell counts were observed with the G10 diet (p &lt, 0.05). Garlic significantly decreased serum cholesterol in all of the experimental groups. Serum albumin was significantly higher in the G10 and G20 diets (p &lt, 0.05). Immediately after the overcrowding stress challenge, the garlic groups showed significantly higher cortisol levels than the control group, while no significant difference was observed in the glucose concentration among groups. At 1 h post-stress, all of the groups that had been fed a garlic-supplemented diet showed lower cortisol levels than the control group, and this trend was maintained at 6 and 24 h post stress (p &lt, 0.05), and glucose level in all garlic groups was significantly lower than control (p &lt, 0.05). Garlic at 10 g kg−1 in feed can improve apparent fat digestibility and selected blood parameters and can enhance resistance against high-density and net handling stress in Eurasian perch.

The use of insect meal in aquafeed formulations has recently gained attention. Detailed knowledge about the inclusion levels for pikeperch (

Simple Summary Herbal medicine feed supplements are used as growth promoters, immune system stimulants, and to combat stress. We evaluated the effects of garlic powder in the diet of European perch. The inclusion of garlic powder was shown to improve whole body composition, feed digestibility, and biochemical and immunohematological effects, and increased resistance against overcrowding stress. Abstract The supplementation of fish diets with phytogenics can increase growth performance and can modulate immune system response. European perch Perca fluviatilis (initial weight 25.0 ± 0.4 g) were fed a diet including 0 (Control), 10 (G10), 20 (G20), and 30 (G30) g kg−1 garlic powder. No significant difference in the growth parameters and somatic indices were observed. Significantly higher fat digestibility was observed in G10 and G30 diets compared to in the control and G20 diets(p < 0.05). Significantly greater red blood cell and white blood cell counts were observed with the G10 diet (p < 0.05). Garlic significantly decreased serum cholesterol in all of the experimental groups. Serum albumin was significantly higher in the G10 and G20 diets (p < 0.05). Immediately after the overcrowding stress challenge, the garlic groups showed significantly higher cortisol levels than the control group, while no significant difference was observed in the glucose concentration among groups. At 1 h post-stress, all of the groups that had been fed a garlic-supplemented diet showed lower cortisol levels than the control group, and this trend was maintained at 6 and 24 h post stress (p < 0.05), and glucose level in all garlic groups was significantly lower than control (p < 0.05). Garlic at 10 g kg−1 in feed can improve apparent fat digestibility and selected blood parameters and can enhance resistance against high-density and net handling stress in Eurasian perch.

In the present study, a possible nature immunostimulant and growth promoter—humic substances (HS) originating from Siberian leonardite mineraloid—were tested on juvenile Clarias gariepinus performance. Feed additive was applied onto commercial pelleted feed at four HS levels—0, 1, 3, and 6% w/w (HS0, HS1, HS3, HS6, respectively). Diets were tested in five repetitions (in total, n = 1800 individuals, mean body weight 28.1 ± 6.2 g) for 56 days. Growth and production parameters, fish condition and somatic indices, and overall mortality were evaluated after 14, 28, 42, and 56 days of exposure. Whereas, plasma samples were collected only after 0, 28, and 56 days, when fish health status was assessed with biochemical parameters (total proteins, TP, alanine aminotransferase, ALT, aspartate aminotransferase, AST, lactate dehydrogenase, LDH, cholesterol, CHOL, triglycerides, TAG) and fish antioxidant status with glutathione (reduced glutathione, GSH, oxidized glutathione, GSSG, glutathione ratio GSH/GSSG). Although a significantly positive effect of HS feed additive on growth performance was not found in the present study, moderately positive effects were found regarding biochemical parameters (ALT, AST, LDH, CHOL, and TAG) and antioxidants (GSH/GSSG ratio) that were improved especially in the HS3 group.

Effects of feeding dietary defatted black soldier fly (Hermetia illucens) larvae meal (HI) on intestine microbiota, and on histomorphology, oxidative enzyme activities in liver and intestine of pikeperch (Sander lucioperca) were investigated. Four isoproteic (45% crude protein) and isolipidic (18% ether extract) diets were formulated to include 0% (CO), 9% (HI9), 18% (HI18) and 36% (HI36) of HI as replacement for fishmeal at 0, 25, 50, and 100%, respectively, and were fed to triplicate groups of juvenile pikeperch (initial body weight, 68.7 ± 7.1 g) for 84 days. No adverse effects were detected on the intestine of pikeperch fed diet groups, in terms of histomorphology (P > 0.05), while fish fed free or low levels of HI (≤ 9% in diet) showed significant liver degeneration (P < 0.05). Dietary HI significantly affected the oxidative enzyme activities of catalase and glutathione peroxidase in the liver, and glutathione S-transferase in the intestine (P < 0.05), while activity of superoxide dismutase in both liver and intestine was HI-dose independent (P > 0.05). Feeding HI-containing diets positively modulated the richness and diversity of intestinal microbiota, especially for HI18 group (P < 0.05). Inclusion HI up to 18% (50% fishmeal replacement) in pikeperch diets increased abundance of Clostridium, Oceanobacillus, Bacteroides, and Faecalibacterium genera, whereas the predominant bacterium, Cetobacterium was found in control and HI36 groups. This study reveals the potential of HI as an immune and health booster for juvenile pikeperch.

Simple Summary The replacement of fishmeal by insect meal is a promising strategy to obtain more sustainable fish feeds, a major goal in aquaculture. Black soldier fly Hermetia illucens larva meal has a high crude protein and fat content, essential for omnivorous and carnivorous fish. We used partially defatted H. illucens larva meal as a substitute for 20%, 40% and 60% of the fishmeal in standard diets for Eurasian perch and measured its effect on growth performance, feed utilization, body indices, fish body composition and blood indices. We found no significant differences in survival, size heterogeneity, hematology indices; or in whole-body dry matter, crude protein and ether extract content. The 60% inclusion reduced final body weight, specific growth rate, feeding rate, protein efficiency ratio, condition factor and hepatosomatic index. The fish-in-fish-out index decreased proportionally with increased H. illucens meal inclusion. Partially defatted H. illucens larva meal seems to be a promising alternative to fishmeal for Eurasian perch nutrition at moderate inclusion level. Abstract Insect meal is gaining increased attention in aquafeed formulations due to high protein content and an essential amino acid profile similar to that of fishmeal. To investigate insect meal in feed for European perch Perca fluviatilis, a promising candidate for European intensive culture, we replaced standard fishmeal with partially defatted black soldier fly Hermetia illucens larva meal at rates of 0%, 20%, 40% and 60% (groups CON, H20, H40 and H60, respectively) and compared growth performance, somatic indices, hematological parameters, whole-body proximate composition and occurrence of spleen lipidosis. In addition, we assessed the economic and environmental sustainability of the tested feeds by calculating economic conversion ratio (ECR) and economic profit index (EPI). The tested groups did not differ in survival rate. Significant differences were documented in final body weight and specific growth rate, with the highest values in CON, H20 and H40. The proximate composition of fish whole-body at the end of the experiment did not differ in dry matter, crude protein or ether extract, while organic matter, ash and gross energy composition showed significant differences. The fatty acid content and n-3/n-6 ratio showed a decreasing trend with increasing H. illucens larva meal inclusion. No differences were found in hematological parameters among tested groups. The H. illucens larva meal inclusion significantly affected ECR and EPI, even at 20% inclusion level the cost of diets did not differ from the control fish meal based diet. Results suggested that 40% inclusion of H. illucens larva meal can be used successfully in standard diets for perch.

Background: Yellow mealworm (Tenebrio molitor) larvae meal (TM), one of seven approved insect species used in aquafeeds, is a frequently investigated candidate for fish diets. Results: This study aimed to investigate the effects of dietary defatted TM on production performance, serum biochemistry, nutrient digestibility, fillet traits, intestinal microbiota, and environmental impacts of perch (Perca fluviatilis). Four experimental diets, characterized by defatted TM inclusion levels of 0, 6.8, 13.5 and 20.3%, respectively, or 0, 25, 50, and 75% at the expense of fishmeal (TM0, TM25, TM50, and TM75, respectively) were fed to juvenile perch (bodyweight 20.81 ± 3.36 g, total length 117.7 ± 7.2 mm) (quadruplicated per diet) for 105 days. Inclusion levels of 6.8% or 25% fishmeal replacement by defatted TM did not show a significant effect on specific growth rate and feed conversion ratio (P > 0.05), while further levels of 13.5 and 20.3%, or 50 and 75% fishmeal replacement with defatted TM, respectively, displayed a significant delay in these indices compared to the control diet (P < 0.001). The aspartate aminotransferase activities in perch’s serum increased with increasing dietary TM (P = 0.044). Nutrient digestibility of perch exhibited TM-dose dependent (P < 0.05). Dietary defatted TM did not lead to any significant changes in the fillet composition of perch (P > 0.05). Defatted TM did not modify diversity of fish gut microbiota (Chao1 index, P = 0.742; Shannon index, P = 0.557; and observed species, P = 0.522), but significantly reduced abundance of Lactobacillus (P = 0.018) and Streptococcus (P = 0.013) while fed TM75 relative to TM0. TM-containing diets generated a comparable amount of total solid waste and solid phosphorus waste with TM0, except TM25, whereas solid nitrogen waste significantly increased with elevated TM levels (P < 0.001). Perch fed TM25 was comparable with TM0 for global warming potential, acidification, and land use (P > 0.05), whereas TM50 and TM75 exerted heavier burdens on energy use, eutrophication, and water use than TM0 (P < 0.001). Fishmeal replacement by TM significantly reduced economic fish-in fish-out (P < 0.001).Conclusion: The inclusion of 6.8% or 25% fishmeal replacement by defatted insect meal (T. molitor) in European perch diets resulted in comparable production performance but entailed heavier burdens associated with solid outputs waste and environmental impacts. The present study underlined the major bottleneck of a substantial inclusion of defatted insect meal (T. molitor) in fish diets associated with solid nitrogen waste and environmental consequences associated with one unit of farmed perch produced. Our multidisciplinary study suggested important aspects while formulating diets for fish, using insect meals regarding production performance and environmental issues.

Stable isotope analysis was conducted to investigate stable isotope ratios of carbon (δ13C) and nitrogen (δ15N), diet-tissue discrimination factors of carbon (Δ13C) and nitrogen (Δ15Ν). Bayesian mixing models were performed to assess relative contribution of insect meal and other ingredients to the development of tissues of European perch (Perca fluviatilis). Accordingly, four experimental formulations, characterized by the increasing inclusion levels of yellow mealworm (Tenebrio molitor) larvae meal (TM) at 0, 6.8, 13.5 and 20.3% as replacement for fishmeal at 0 (TM0), 25 (TM25), 50 (TM50) and 75% (TM75), respectively, were fed to juvenile perch (initial bodyweight, 20.81 ± 3.36 g) in a recirculated aquaculture system for 105 days. δ13C and δ15N of TM were -16.75 and 3.53‰ and significantly distinguished from other terrestrial and marine feed components (P 0.05) but did reduce in muscle (P 0.95). Soy-derived ingredients, soybean meal and soy protein, were an important ingredient in the development of all tissues regardless of dietary TM. The present study provided insightful information on the role of various diet components in perch tissues, which could underlie further development of aquafeed formulations for emerging perch farming in Europe.

Simple Summary Restocking programmes are of crucial importance for the stabilisation of wild sturgeon stocks. Despite massive restocking, the survival rate of post-released fish is very low. The low survival is most likely caused by poor fish adaptability due to hatchery rearing practices. This study aimed to provide a deeper understanding of the effect of different feeding applications with day and night regimes and periods of starvation on the modified swimming behaviour of Siberian sturgeons reared in recirculating aquaculture conditions. Our data showed that the modified behaviour of the Siberian sturgeon in our study was caused by fish starvation rather than by the method of feed application or day/night light regimes. Abstract Restocking programmes of different fish species have been implemented worldwide. However, the survival of hatchery-reared fish after release to riverine ecosystems is at a very low level. One of the reasons for the high mortality rate of post-released fish is their modified swimming behaviour due to the hatchery rearing practice. To investigate one of the possible causes for modified swimming behaviour, Acipenser baerii larvae were exposed to surface- and bottom-feeding applications with day and night light regimes in a factorial design. We also analysed the effect of 5 and 10 days of starvation after different feeding applications on sturgeon swimming behaviour. The surface-feeding application was previously expected to promote the frequent Siberian sturgeon swim up to the mid- and top-water layers in our rearing facilities. However, our results indicated that the modified behaviour of the Siberian sturgeon in our study was caused by fish starvation and a possible predator-free environment rather than by the method of feed application or the day/night light regimes. These results may be used to improve the implementation of restocking programmes either through modified hatchery rearing practice or the training of foraging skills with predator stimuli.

We assessed swimming capacity, energy expenditure, and physiological responses of European perch (Perca fluviatilis) fed four isonitrogenous and isoenergetic diets containing yellow mealworm (Tenebrio molitor) larvae meal at 0, 25, 50, and 75% substitution for fishmeal (abbreviated diets, TM0, TM25, TM50, and TM75). Each diet was fed to quadruplicate group of perch (initial biometrics, body weight 20.81 ± 3.36 g, total length 11.77 ± 0.72 cm) for 119 days. At the terminal of feeding trial following 24 h starvation, eighty fish (20 fish/diet group) were individually selected for swimming performance tests, which were conducted in a 10 L enclosed swimming tunnel with velocity increased from 5 cm/s in 2 cm/s increments every 60 s. Exercised fish, fish experienced swimming tests, and non-exercised fish, fish not involved in swimming tests were, at the same time, sampled for serum biochemistry, muscle traits. Whole-body of non-exercised fish were also analyzed for proximate composition and fatty acid profile. Critical swimming speed (Ucrit, cm/s and body length/s), oxygen consumption (MO2, mg/kg/h), and energy cost of transport (COT, J/kg/m) of perch did not differ among diet treatments. Exercised perch significantly increased serum glucose and cortisol compared to non-exercised fish. Substitution of fishmeal by T. molitor larvae meal induced significant changes in aspartate aminotransferase across treatment groups, lactate dehydrogenase in TM0 and TM75, K+ concentration in fish fed TM75, and muscle water content in TM50 of exercised compared to non-exercised perch. Oleic acid of whole-body fish had a significant linear correlation with the critical swimming speed of European perch. Since fish swimming behavior is an indicator of animal welfare, our findings suggest that dietary insect meals could ensure the welfare of farmed fish.

Insect meal is gaining increased attention in aquafeed formulations due to high protein content and an essential amino acid profile similar to that of fishmeal. To investigate insect meal in feed for European perch Perca fluviatilis, a promising candidate for European intensive culture, we replaced standard fishmeal with partially defatted black soldier fly Hermetia illucens larva meal at rates of 0%, 20%, 40% and 60% (groups CON, H20, H40 and H60, respectively) and compared growth performance, somatic indices, hematological parameters, whole-body proximate composition and occurrence of spleen lipidosis. In addition, we assessed the economic and environmental sustainability of the tested feeds by calculating economic conversion ratio (ECR) and economic profit index (EPI). The tested groups did not differ in survival rate. Significant differences were documented in final body weight and specific growth rate, with the highest values in CON, H20 and H40. The proximate composition of fish whole-body at the end of the experiment did not differ in dry matter, crude protein or ether extract, while organic matter, ash and gross energy composition showed significant differences. The fatty acid content and n-3/n-6 ratio showed a decreasing trend with increasing H. illucens larva meal inclusion. No differences were found in hematological parameters among tested groups. The H. illucens larva meal inclusion significantly affected ECR and EPI, even at 20% inclusion level the cost of diets did not differ from the control fish meal based diet. Results suggested that 40% inclusion of H. illucens larva meal can be used successfully in standard diets for perch.

A palladium-catalyzed one-pot reaction for the synthesis of benzo[b]carbazolediones is described which proceeds by amination of 2,3-dibromonaphthoquinone, Suzuki cross-coupling with (2-bromo­phenyl)boronic acid, and subsequent intramolecular C–N Buchwald–Hartwig cyclization with amines.

A palladium-catalyzed one-pot reaction for the synthesis of benzo[b]carbazolediones is described which proceeds by amination of 2,3-dibromonaphthoquinone, Suzuki cross-coupling with (2-bromo­phenyl)boronic acid, and subsequent intramolecular C–N Buchwald–Hartwig cyclization with amines.