Aquaculture Feed Research Articles

Utilizing Invasive Pterygoplichthys pardalis as a Sustainable Fish Meal Substitute and Euphorbia hirta Extract Supplement: Effects on Growth Performance, Organosomatic Indices, Hematological Profiles, and Serum Biochemistry in Chinese Bullfrogs (Hoplobatrachus chinensis).

This research examined the efficacy of substituting commercial fish meal (CFM) with Pterygoplichthys pardalis meal (PPM) in Hoplobatrachus chinensis diets, with and without Euphorbia hirta extract (EHE) supplementation. The study utilized six dietary treatments: a control diet (0% PPM, no EHE) and five experimental diets with varying PPM levels (0%+, 25%+, 50%+, 75%+, and 100%+), each fortified with 300 mg/kg EHE. The experiment spanned 90 days. The analysis revealed that PPM exhibited superior amino acid profiles compared to CFM, both in quality and quantity, while CFM demonstrated higher fatty acid content. The growth metrics showed a significant decline only in the group receiving 100% PPM replacement with EHE supplementation. Most organosomatic indices remained consistent across the treatments, with the exception of intraperitoneal fat, which decreased in all EHE-supplemented groups. Blood parameters, including white blood cells, red blood cells, and hematocrit, along with serum proteins (total protein, globulin, and albumin), displayed an upward trend in all EHE-supplemented groups. The 50%+ and 75%+ PPM replacement groups exhibited significantly elevated serum glucose levels (p < 0.05). Liver enzymes (alanine transaminase and aspartate transaminase) showed no significant variations among the treatments. The results indicate that PPM can serve as an effective replacement for up to 75% of CFM in H. chinensis feed, without compromising their growth performance. Moreover, supplementing with EHE helps to enhance essential biochemical indices in the body, without adversely affecting liver function. This investigation offers valuable perspectives on the development of sustainable aquaculture feed and the potential application of invasive fish species in aquatic animal nutrition.

Contaminated Characteristics Variation in Different Aquaculture Modes: A Case Study in Northern China

Various aquaculture modes have been developed to satisfy the growing demands of aquatic products. The contaminated characteristics may distribute along with the aquaculture modes, threatening the ecological environment to varying degrees. Herein, the five most common aquaculture modes (small-scale intensive mode, extensive free-range mode, concentrated contiguous mode, funnel-type mode, and recirculating aquaculture system) were selected to study the contaminated characteristics (including nine kinds of water quality parameters and eight kinds of antibiotics) in Henan Province, a province in northern China, and analysed using high-performance liquid chromatography tandem secondary mass spectrometry (HPLC–MS/MS). The funnel-type mode, as a unique mode developed in Henan Province, appears highest in nutrient content, wherein TN and TP concentrations reach 29.28 mg/L and 2.20 mg/L, respectively. The small-scale intensive mode has the highest average antibiotic concentration in five different aquaculture modes, with a concentration of 502 ng/L. Overall, the most abundant antibiotic was quinolones (QNs), followed by sulfonamides (SAs), chloramphenicols (CAs), and tetracyclines (TCs). Pearson correlation analysis showed that ENR had a strong positive correlation with TN, TP, and Zn, indicating the enrofloxacin (ENR) may have existed as the addictive in aquaculture feed. Moreover, the risk quotient (RQ) analysis indicated that ENR posed a medium to high risk, highlighting the importance of antibiotics man-agement in aquaculture. This work provides theoretical guidance for the formulation of aquaculture water pollutant control of different aquaculture modes.

Evaluation of the Effect of Various Substrates on the Attachment of Juvenile Brown Mussel (Mytilopsis adamsi)

Brown mussel (Mytilopsis adamsi) is a potential alternative feed for lobster and crustacean aquaculture in Indonesia, with a balanced nutritional content of 13.29% protein and 80.30% water content, and does not compete with human food needs. This study was conducted because brown mussels are not consumed by humans so they can be concentrated as lobster feed without competing food sources. Cultivating brown mussels is expected to increase lobster productivity in Indonesia and provide consistent fresh feed for cultured lobsters. The development of brown mussels as lobster feed is also encouraged by the Ministry of Marine Affairs and Fisheries (KKP) to overcome the problem of inconsistent feed supply and improve feed quality for lobsters. This study aimed to assess the effect of four types of substrates (80% paranet, PE rope, white net, and paris cloth) on the attachment of juvenile brown mussels for 30 days at BPBL West Lombok, using a completely randomized design with 6 replicates. The results showed that PE rope had the highest attachment density in the water column (1.62 fish/cm2) and at the bottom of the container (6.91 fish/cm2). The absolute growth rate was recorded in white netting (860 µm for AP length and 1630.17 µm for DV), while the highest specific growth rate was found in paris cloth for AP (0.154%/day) and PE rope for DV (0.186%/day). It can be concluded that the study showed that PE rope was the best substrate in terms of density. White Net excelled in the absolute growth of brown mussel juveniles. Fabric stood out for AP length-specific growth rate, while rope performed best for DV-specific growth rate. The substrate at the bottom of the container consistently gave better results than that in the water column. Further research is recommended to assess the effect of varying attachment density on other substrate types, as well as longer rearing duration.

The study of high-protein plant components on the example of soybeans and corn for aquaculture feed

It is important to use nutritious compound feeds with high content of protein in order to obtain qualitative marketable fish products under an intensive cultivation. During the production of high-protein aquaculture feeds, protein-rich animal and plant ingredients should be added to the composition. To such components refer: fish flour, meat-and-bone meal, wheat, corn, various types of soybeans, etc. Animal ingredients can be partially replaced by vegetable ingredients, but should not be 100%. Popular plant-based feed additives are soybean and corn. They are rich sources of plant protein which make them an ideal supplement to form a complete fish diet, especially in conditions of the intensive cultivation. These ingredients are often cheaper in comparison to animal proteins, which is the reason why the use of these ingredients makes feed more affordable for fish producers. For producers, semi-finished products of two or more ingredients are produced now as pellets or dry mixes. It is made to simplify the production process. In the majority of cases, these additives include a combination of animal protein and plant protein. This paper considers plant components such as soybean and corn in combination with fish flour for the manufacture of compound feeds. It also presents amino acid compositions of these components. Studies on the determination of the amount of proteins, fats and carbohydrates in experimental feeds containing soybean and corn are conducted and described. In the course of the experiment it is revealed that the feed with soybean content has a higher percentage of crude protein content, but the feed with corn has a higher content of carbohydrates in its composition.

Impact of β-Carotene Enrichment on Carotenoid Composition and Gene Expression in Artemia Metanauplii.

Carotenoids play essential nutritional and physiological roles in aquatic animals. Since aquatic species cannot synthesize carotenoids de novo, they must obtain these compounds from their diet to meet the physiological and adaptive requirements needed in specific aquaculture stages and conditions. Carotenoid supplementation in Artemia represents a promising strategy to enhance pigmentation, health, and growth in aquaculture species, particularly in larvae and other early developmental stages. In this study, a β-carotene enrichment process was applied to Artemia metanauplii to investigate the biological fate and potential effects of β-carotene. The results indicated significant β-carotene uptake by Artemia, with peak levels observed at 12 h. Alongside β-carotene, two xanthophylls-canthaxanthin and echinenone-were detected in Artemia, each exhibiting distinct patterns during the enrichment and subsequent depletion phases. The transcriptome analysis identified 2705 differentially expressed genes (DEGs), offering valuable insights into gene functions associated with carotenoid absorption, metabolism, and antioxidant mechanisms. The findings suggest that β-carotene enrichment enhances metabolic activity and energy pathways, supporting the physiological functions of Artemia. Notably, unlike other crustaceans, Artemia lack certain enzymes necessary for converting β-carotene into astaxanthin, restricting them to producing keto-carotenoids like canthaxanthin. Furthermore, the study highlights the upregulation of genes encoding lipid transport proteins, such as CD36 and ABC transporters, which may contribute to carotenoid absorption in Artemia. Additional functional insights are provided by the gene BCO2, which regulates pigmentation by preventing excessive carotenoid accumulation, along with ketolase and hydroxylase enzymes in carotenoid metabolic pathways. This research advances our understanding of carotenoid metabolism in crustaceans, with potential implications for aquaculture nutrition and feed formulation.

A preliminary study on the effects of substituting fishmeal with defatted black soldier fly (Hermetia illucens) larval meal on Asian seabass (Lates calcarifer) juveniles: Growth performance, feed efficiency, nutrient composition, disease resistance, and economic returns.

This study aims to develop an alternative aquafeed derived from insect meal for Lates calcarifer juveniles, with the objectives of exploring the physiological performance, biological parameters, and economic analysis of substituting fishmeal (FM) with defatted black soldier fly (Hermetia illucens) larvae (BSFL) as part of the diet of L. calcarifer juveniles. Five practical diets were formulated to include 0% (BSFL0, serves as control group), 5% (BSFL5), 10% (BSFL10), 15% (BSFL15), and 20% (BSFL20) of BSFL meal, partially or fully replacing FM, respectively. Each diet was randomly assigned to triplicate groups of 30 fish (10.70 ± 0.07 g) per tank (300 L). The fish were fed twice daily to apparent satiation. A 56-day feeding trial was conducted to evaluate the impacts of defatted BSFL meal replacing FM on the growth performance, feed efficiency, composition analysis of fish muscle, cumulative mortality rate challenged with Vibrio parahaemolyticus, and economic returns of L. calcarifer. These results show that differences in weight gain and specific growth rate among the different treatments were statistically significant (p < 0.05), except for the absence of significant variation (p < 0.05) between BSFL0 and BSFL5, and followed by BSFL10 > BSFL0 > BSFL5 > BSFL15 > BSFL20. However, the feed conversion ratio and protein efficiency ratio showed the opposite trend as above. Although the diets experienced a decline in crude protein content and an increase in crude fat content with the increasing proportion of BSFL substituting FM, the crude protein and fat content of fish muscle were only slightly influenced. It is worth mentioning that levels of nonessential amino acids, delicious amino acids, saturated fatty acids, omega-6, omega-9 in BSFL10 group all showed an increase compared with the control group. After a 7-day challenge test with V. parahaemolyticus, the cumulative mortality rates of the BSFL5 and BSFL10 groups, respectively, dropped to 5.20%, 5.28% compared to the control group's 16.88%; however, the mortality rates of BSFL15 (34.67%) and BSFL20 (41.77%) groups were found to be significantly (p < 0.05) increased. From an economic perspective, the incidence cost for each experimental group showed a trend as BSFL10 < BSFL0 < BSFL5 < BSFL15 < BSFL20, whereas the profit index in each treatment exhibited the opposite trend as above. It was concluded that low (5%) or moderate (10%) levels of BSFL substituting FM in aquaculture feed could improve the physiological performances, disease resistance, and economic returns of L. calcarifer. However, excessive substitution (>15%) leads to a negative effect. From an economic point of view, 10% inclusion of BSFL in practical diets is recommended for L. calcarifer juveniles.

Dietary intake of soya flour synergistically influences carcinogenic action in fish, Channa punctatus.

Influence of dietary intake on Physiological and biochemical status of the living being is an established fact. Similarly, certain Micronutrients associated with the biochemical component of parent products and their byproducts are often deleterious to the Consumers. A classical example is Cyclopropenoid fatty acids (CPFA), a natural constituent present in triglyceride fraction of the fat of cotton plants. It acts Synergistically with aflatoxin B1, if at all present in the diet due to infestation of some toxic fungi A. flavus and A.parasiticus. Studies on Channa punctatus, an air breathing teleost administered with three concentrations of pure crystalline aflatoxin B1( 15, 30 and 45 ppm) intraperitonially and reared on standard diet formulation (SDF) added with Soya flour (SF) Supplements. In contrast, the pathological lesions in the group reared on Soya flour supplement was almost comparable to the control group receiving similar concentration of aflatoxinB1 and reared on SDF. The Soya flour is usually used as dietary supplement for pets and livestock in order to meat protein requirements from the left out amount of the oil following extraction. In particular, the findings gain significance on account of the fact that the Soya flour (SF) is one of the major ingredientsof aqua culture feed formulation all through the country.. KEYWORDS :Dietary factors , Aflatoxin B1, Synergistic Action, Carcinogenicity.

Influence of Continuous and Short-Term Direct Current Stimulation on the Growth and Nutrient Composition of Nitzschia closterium f. minutissima with Prospects for Large-Scale Production

This study investigates the effects of continuous and short-term direct current (DC) stimulation on the growth and nutrient composition of Nitzschia closterium f. minutissima, a marine diatom with significant potential in aquaculture feed. We explored the optimal conditions of DC stimulation by applying both short-term and continuous treatments at varying voltages (0 V, 1 V, 3 V, 5 V, 10 V for short-term; 0 V, 0.05 V, 0.5 V, 1 V for continuous). The results demonstrated that short-term DC stimulation significantly enhanced cell density and lipid accumulation, with maximum cell density increasing by 13.14% under 1 V stimulation compared to the control. However, continuous stimulation was less effective and showed growth inhibition in several cases. Nutrient analysis revealed that short-term stimulation, particularly at 3 V, led to a 67.66% increase in lipid content, while moderate continuous stimulation (0.5 V) showed a 39.47% increase in biomass dry weight. These findings suggest that short-term DC stimulation is a promising approach to optimize microalgal growth and nutrient accumulation for large-scale aquaculture production.

Amino acid composition of different sources of protein feed for aquaculture

Properly formulated feed helps increase the profitability of aquaculture production and achieve high quality products. In addition, it is important to take environmental aspects into account when producing compound feeds for aquaculture. It is necessary to use ingredients that do not harm the environment and do not pollute water. Production processes should also be optimized to reduce waste and maximize the use of all feed components. With the development of technology and scientific research in the field of aquaculture, new methods and solutions are emerging to improve the quality of feed. For example, adding probiotics and antioxidants can boost fish immunity and improve their growth. It is also important to take into account the characteristics of the digestive system of each type of fish when creating compound feeds to ensure optimal absorption of nutrients. In general, the quality of feed plays an important role in the successful development of aquaculture production. Continuous improvement of feed composition and production technologies helps improve production efficiency and ensure high productivity. The article examines the amino acid composition of various protein sources used in aquaculture feeds, such as fishmeal, black soldier fly larvae, vegetable protein concentrate, and provides a brief description of the amino acids necessary for the fish body. During the study, it was revealed that different types of protein sources contain different amounts of essential amino acids necessary for adequate nutrition of fish. Studying and comparing the amino acid composition of different protein sources allows us to optimize feed for aquaculture, providing fish with all the necessary nutrients for their health and rapid growth.

Effects of angler’s groundbaits on fish physiology and growth

Although angler’s groundbaits (GBs) can be an important food resource for fish, we do not know much about the effects of GB consumption on the growth and health of fish. To fill this knowledge gap, we conducted a controlled, six-week long feeding trial (feeding ration: 2% of body weight) with common carp at 22 °C (Cyprinus carpio, mean initial body weight: 557 g) to test the effect of two GBs composed mostly of animal-derived ingredients (AN-GBs) and two plant-based GBs (PL-GBs) relative to one aquaculture feed, as a control (five treatment altogether). Consumption of PL-GBs resulted in lower growth rate than AN-GBs, presumably due to the low protein content. However, the unit biomass increment per unit nitrogen input was higher in PL-GBs. Although PL-GBs resulted in reduction of hepatic energy reserves, hepatosomatic index, viscerosomatic index, and body condition did not differ among the treatments. We did not find differences in expression of inflammatory cytokines in the liver. In conclusion, AN-GBs more effectively increases the carrying capacity of fisheries, but fish sequester a higher portion of nitrogen content of PL-GBs –PL-GB input can be more effectively counterbalanced by fish removal. Finally, the GB consumption does not pose a health risk to fish.

Strategies for feeding tilapia in smallholder aquaculture systems: a study of aquaculture feed access and availability in two districts of Northern Province, Zambia

ABSTRACT Aquaculture contributes to agricultural development, economic growth, and poverty reduction initiatives in Zambia. In northern and rural regions of the country, development requires improvements to the management of local and farm-generated inputs. Fish farmers have limited market access and purchasing power, which restricts access to commercial inputs, such as formulated feeds and chemical fertilizers. Instead, farmers adopt integrated-agriculture-aquaculture (IAA) practices, whereby on-farm resources supply essential inputs. Research is limited regarding local systems of resource management, and this hinders development of innovations for improving efficiency. This mixed-methods study explored local patterns of resource utilization. Smallholders (n = 63) participated in surveys and interviews regarding resource management. A series of quantitative analyses, including descriptive statistics, principal component analyses (PCA), and multinomial logistic regression (logit) models, identified relationships between these resources, household livelihood, and system productivity. Qualitative analyses explored farmer perceptions regarding seasonal resource availability. Results suggested that livestock manure, homemade feeds comprising maize and soybean, garden residues, and kitchen wastes were the most frequently selected inputs. Logit models of feeding intensity found that income, proximity to Luwingu Town, experience in aquaculture, and access to extension services were key household resources. High-intensity feeding strategies incorporated commercial feeds, chemical fertilizers, as well as home-made feeds containing a wide diversity of both high- and low-quality ingredients. Low-intensity feeding strategies incorporated only farm waste and termites. Potential innovations that may improve system performance in resource poor contexts are considered and recommendations for additional research are offered.

Nutrient content of various water-based alternative protein sources as candidates for raw material feed in aquaculture

Nutrient content of various water-based alternative protein sources as candidates for raw material feed in aquaculture

Exploring the Freshwater Cladocera (Pleuroxus spp.) as New Potential Live Feed in Aquaculture

In freshwater lakes, cladocera play a crucial role in the food chain, as they are the primary source of nutrition for nearly all aquatic species. Pleuroxus spp. are very suitable for aquaculture due to their ease of handling, rapid growth, non-selective filter feeder, high nutritional value, and remarkable ability to adapt to many environmental conditions. Silver barbs are in high demand in the aquaculture business due to their excellent flavours and rapid development rate. In this study, Pleuroxus spp. was cultured in a control condition with water quality maintained at the room temperature of 26 ± 1 °C and pH of 7.0 ± 0.5. Five treatments of Pleuroxus spp. were prepared, which comprised of T1 (control) = unfed, T2 = coffee grounds, T3 = corn flour, T4 = wheat flour, and T5 = sugarcane waste. Pleuroxus spp. were fed with a selected diet solutions at a concentration of 0.5 g/L daily. The result shows that Pleuroxus spp. given T3 (24.88 ± 5.48 ind/mL) had a greater population density than T4 (22.13 ± 4.83 ind/mL), T2 (21.06 ± 5.27 ind/mL), and T5 (20.56 ± 4.92 ind/mL) dietary treatments. Pleuroxus spp. given T3 had the greatest survival rate (97.9 ± 9.8%) when compared to other diets, T4 (86.81 ± 19.07%), T2 (82.71 ± 16.56%), and T5 (75.00 ± 21.08%). Silver barb showed the highest amount of daily weight gain in treatment T3 (0.11 ± 0.001 mg/days; p &lt; 0.05) compared with other dietary treatments. The maximum specific growth rate (SGR) (%) was achieved when fed with T3 (13.37 ± 0.02%; p &lt; 0.05). The feed conversion ratio (FCR) was shown to be significantly different (p &lt; 0.05). The FCR of larvae fed with different nutritional treatments ranged from 1.22 to 4.12, depending on the treatment. In comparison to other diets, the T3 treatment (1.22 ± 0.03) achieved the highest FCR ratio. In short, pre-feeding of zooplankton with prospective diets has built a baseline of improved aquaculture feeding procedures that may be employed in the future aquaculture businesses.

An integrated three-stream network model for discriminating fish feeding intensity using multi-feature analysis and deep learning.

Feed costs constitute a significant part of the expenses in the aquaculture industry. However, feeding practices in fish farming often rely on the breeder's experience, leading to feed wastage and environmental pollution. To achieve precision in feeding, it is crucial to adjust the feed according to the fish's feeding state. Existing computer vision-based methods for assessing feeding intensity are limited by their dependence on a single spatial feature and manual threshold setting for determining feeding status constraints. These models lack practicality due to their specificity to certain scenarios and objectives. To address these limitations, we propose an integrated approach that combines computer vision technology with a Convolutional Neural Net-work (CNN) to assess the feeding intensity of farmed fish. Our method incorporates temporal, spatial, and data statistical features to provide a comprehensive evaluation of feeding intensity. Using computer vision techniques, we preprocessed feeding images of pearl gentian grouper, extracting temporal features through optical flow, spatial features via binarization, and statistical features using the gray-level co-occurrence matrix. These features are input into their respective specific feature discrimination networks, and the classification results of the three networks are fused to construct a three-stream network for feeding intensity discrimination. The results of our proposed three-stream network achieved an impressive accuracy of 99.3% in distinguishing feeding intensity. The model accurately categorizes feeding states into none, weak, and strong, providing a scientific basis for intelligent fish feeding in aquaculture. This advancement holds promise for promoting sustainable industry development by minimizing feed wastage and optimizing environmental impact.

Feeding global aquaculture.

The growth of animal aquaculture requires ever more feed. Yet, fish and crustacean farming is argued to be sustainable because wild fish use is low and has improved over time. Here, accounting for trimmings and by-products from wild fish in aquaculture feed, and using four different sources of industry-reported feed composition data, we find ratios of fish inputs to farmed outputs of 0.36 to 1.15-27 to 307% higher than a previous estimate of 0.28. Furthermore, a metric that incorporates wild fish mortality during capture and excludes unfed systems raises the wild fish mortality-to-farmed fish output ratio to 0.57 to 1.78. We also evaluate terrestrial ingredients in aquaculture feeds. Widely cited estimates of declines in wild fish use from 1997 to 2017 entailed a trade-off of more than fivefold increase in feed crops over the same period. Our assessment challenges the sustainability of fed aquaculture and its role in food security.

Rational Nitrogen Reduction Helps Mitigate the Nitrogen Pollution Risk While Ensuring Rice Growth in a Tropical Rice–Crayfish Coculture System

The incorporation of aquaculture feed within a rice–crayfish coculture system significantly enhances nitrogen cycling, thereby diminishing the reliance on chemical fertilizers. However, this benefit is often overlooked in practice, and farmers continue to use large quantities of chemical fertilizers to maximize production, resulting in excessive soil fertility and water nitrogen pollution. Thus, avoiding nitrogen pollution in rice–crayfish coculture systems has become a pressing issue. In this study, we conducted a two-year experiment with two rice cultivars, and a 33.3% reduction in nitrogen fertilizer in a rice–crayfish coculture system (RC), to systematically analyze the overall nitrogen balance, rice nitrogen nutrition, and soil fertility, as compared with a rice monoculture system (RM). Our findings revealed the following: (1) Under the 33.3% reduction in nitrogen fertilizer, the nitrogen surplus in the rice–crayfish coculture system was comparable to that in the rice monoculture, and was controlled at an environmental safety level. (2) Nitrogen utilization efficiency and the accumulation of nitrogen in the rice–crayfish coculture were comparable to those in the rice monoculture. The nitrogen cycle in this system was able to provide the nitrogen required for rice growth after nitrogen fertilizer reduction. (3) The rice–crayfish coculture significantly improved the overall soil fertility and the effectiveness of soil nitrogen nutrition. Furthermore, cutting off the application of nitrogen fertilizer after the mid-tillering stage effectively controlled the total nitrogen content in soil after rice maturity. In conclusion, reducing nitrogen fertilizer in a rice–crayfish coculture system is feasible and beneficial. It ensures rice production, reduces the risk of excessive nitrogen surplus and surface pollution, and promotes a greener, more environmentally friendly paddy field ecosystem.

Nitrogen, phosphorus, and carbon dynamics in biofloc system of Nile tilapia fed with high non-starch polysaccharides diet

While microbiota need to consume organic carbon to maintain water quality, commercial aquaculture feed produces a post-feeding waste with a carbon to nitrogen ratio that is too low to allow the bacteria to mineralize all the waste. The goal of this study was to investigate the effects of replacing starch-rich ingredients used in a Control-diet with non-starch polysaccharides (NSP) rich ingredients resulting in a High-NSP-diet on the water quality and nutrient budgets in biofloc tanks with Nile tilapia (Oreochromis niloticus). The main NSP-rich ingredients in the High-NSP-diet were palm kernel meal, rice bran and corn gluten feed. Both diets were isonitrogenous, but the High-NSP-diet contained 3 times more fiber than the Control-diet.After 8 weeks of cultivation, the individual fish growth and feed conversion ratio was similar between two dietary treatments, but due to a lower survival in tanks fed the High-NSP-diet the total biomass gain was slightly better in the Control-diet tanks. The contribution of biofloc to fish growth with the High-NSP-diet was 17 %, compared to 14 % when feeding the Control-diet. The water quality was similar between both dietary treatments, with less accumulation of nutrients in the water column in the High-NSP-diet tanks. This was shown by a 4 % lower retention efficiency of carbon (C), 12 % of nitrogen (N) and 7 % of phosphorus (P) in the water column in High-NSP-diet fed tanks than in the Control-diet tanks. The High-NSP-diet did not affect the C, N, and P concentration of the biofloc, with a relatively stable concentration of C and N among weeks and a steady increase in P concentration until week six (W6). The biofloc concentration increased until W6 and decreased in week eight.Correlation analysis revealed strong correlations between the concentrations of total suspended solids (TSS), total organic matter (TOM) and NO3, and between TSS and Chl-a. Subsequent regression analysis showed that the TSS concentration can be best predicted based on the TOM concentrations in tanks fed the Control-diet and based on the NO3 concentration in tanks fed the High-NSP-diet. This approach will help modellers or farmers to predict the amount of TSS based on a limited number of other water quality parameters. Economic analysis showed that in spite of a lower production at system level when feeding the High-NSP-diet, due to the lower cost of this diet, the effect on income is negligible, with a higher 0.03 USD profit per kg fish produced compared to the Control-diet.

Sustainable seafood: advances in traceability, assessment, monitoring and resource management

This review presents a synopsis of advances in some techniques and technologies that support seafood traceability while addressing some of the complexities currently challenging the integration necessary to coordinate commercial, national and international efforts in achieving seafood sustainability. These advances rely on tools such as blockchain data handling, eDNA or eRNA (together ‘eNA’) sampling, DNA metabarcoding, artificial intelligence and mobile applications. The microbiota associated with seafood organisms can also be monitored using eNA, to enable detection and management of any potential pathogenic developments in wild or aquaculture stocks. For successful and efficient traceability, it is necessary to guarantee data reliability and to support regulatory auditing. To ensure sustainability, however, also requires sampling, monitoring and assessments of the resource status as well as appropriate management. Effective traceability of seafood-related products will also help to resolve other problems, such as endangered species entering supply chains for aquaculture feed. Considering the still large proportion of seafood that is currently obtained and processed illegally, there is a pressing need for coherent local, national and international policies rooted in shared goals among stakeholders and supported by even-handed enforcement. This has been recently facilitated through a trend to shift liability from fishers to importers, and onwards throughout the value chain. In hand with these regulatory changes, the technologies described here will play a central role in achieving the vision for sustainable seafood supplies by the end of this decade.

Dietary Chitosan Nanoparticles Enhance Growth, Antioxidant Defenses, Immunity, and Aeromonas veronii biovar sobria Resistance in Nile tilapia Oreochromis niloticus

While chitosan is widely used in aquaculture feed, chitosan nanoparticles (CNPs) offer potential advantages due to their enhanced absorption. This study investigated the safe use of CNP levels in Nile tilapia feed, evaluating its impact on growth, immunity, and disease resistance. Five experimental diets were formulated and supplemented with zero chitosan (served as a control group), 1g/kg of chitosan (CS), and 1, 3, and 5 g/kg of CNPs. Each diet was randomly assigned to three replicate groups of 45 fish per group (15 fish/tank) with an average weight of (42.10 ± 0.05g, mean ± S.E.) twice daily (09:00 a.m. and 4:00 p.m.) to apparent satiation for two months. At the end of the feeding trial, fish fed 5 g/ kg of CNPs had the highest growth performance. However, no significant variations (p &gt; 0.05) in somatic index were seen between the experimental groups. All chitosan and CNP-enriched groups exhibited improved intestinal morphology compared to the control group, characterized by increased villus length and width, reduced necrosis of intestinal tips, and better overall tissue integrity, with the CNP 3g and 5g groups demonstrating the most favorable intestinal structure. The CNP-treated groups (3, 5 g/kg) had significantly higher blood indices and serum globulin. Malondialdehyde (MDA) levels were lower in the CNP-treated groups compared to the chitosan macromolecule group. There was a substantial rise in glutathione (GSH), total antioxidant capacity (TAC), phagocytic index, and respiratory burst activity in the 5 g/kg CNP-treated group. The dietary addition of 5 g/kg of CNPs raised mRNA expression for TLR-2, MUC-2, and IGF-1, but there was no significant difference in HSP70 expression across treatments. After the experimental challenge with Aeromonas veronii biovar sobria, the groups that received 3 and 5 g/kg of CNPs exhibited the lowest mortality rates. Overall, the results suggest that including 5g/kg of CNPs in fish food is safe and effective for enhancing their health and growth, making it a promising addition to aquaculture feed.

Optimizing feeding frequencies in fish: A meta-analysis and machine learning approach

Feeding is a critical factor in aquaculture, directly impacting cultivation success and profitability. Feeding frequency determines feed intake and regulates fish appetite and nutrient utilization. However, the effects of increased feeding frequency on fish growth and feed conversion ratio (FCR) can vary depending on species, cultivation conditions, feeding rates. This variability can lead to inconsistencies in interpretations, with individual studies often lacking in statistical power. To address this issue, we analyzed data from 145 study cases across 53 publications to quantify the impact of feeding frequency on average daily weight gain (ADG) and FCR. Our meta-analysis revealed that increasing feeding frequency could reduce FCR, but it did not enhance ADG when daily feed amounts were fixed. Only when each feeding reached satiation did increased feeding frequency boost ADG. We found that the relationship between feeding frequency and ADG in fish is quadratic, with most fish species achieving optimal ADG at four feedings per day. Traditional approaches suggest that fish appetite recovery is linked to gastric evacuation time, defining an optimal feeding interval at 80 % gastric evacuation. However, our research indicates that this approach is not suitable for all fish species. Therefore, we developed a Gradient Boosting Machine (GBM) model that predicts FCR (R2 = 0.9303) and ADG (R2 = 0.7249) based on environmental variables, fish characteristics, culture period, and feeding frequency. This study provides a scientific basis for formulating more efficient and sustainable aquaculture feeding strategies, optimizing growth and feed utilization across different fish species.