Fishmeal In Aquafeeds Research Articles

Vertical Haloponics: Sustainable and Resilient Productions Using Brackish Water

While the rapidly growing global population will require a significant increase in food production in the next years, the current climate, sanitary and geopolitical crises highlight the weaknesses of the actual food production systems, excessively dependent on external inputs and involving extremely complex nested scales and non-linear processes. Thus, appears clearly the need of accelerating the transition toward agricultural solutions and food systems based on the principles of the “Green Deal”, encompassing ecological resilience, environmental sustainability, local production, and universal access to healthy foods. Aquaponics (AP) can provide short and eco-friendly food supply chains with increased resource-use efficiency, high environmental sustainability, and food resilience. The sustainability of AP systems could be further increased by exploiting water resources that are not suitable for other purposes (brackish and salt water - haloponics), applying the vertical farming technology for both aquatic and vegetable species, reducing the use of fish meal in aquafeeds, valorizing the system residues (sludge) for agronomic purposes.The VERTICHALPONICS project aims to develop an innovative food production system by implementing an interdisciplinary approach. Since aquaponics combines recirculation aquaculture and hydroponics, within a close loop, it is considered environment friendly. However, given the different technical approaches, it is necessary to evaluate the differences in impacts and specially to assess whether the vertical system is really resource-efficient and economically viable for farmers, in comparison to the business-as-usual. The environmental and economic sustainability of the system is measured by the mean of a combined LCA and the LCC analysis (EN ISO 14040-44 and ISO 15686-5:2017 standards). The system expansion will be used to evaluate the beneficial effect of reducing the overall environmental burden from by-product recovery and utilization of side wastes, specifically the sludge produced. The method applied are Recipe and IPCC 2013 Global Warming Potential 100a. Environmental impact indicators will be provided using both mid-point and end-point categories thank to the Recipe Method, while the IPCC 2013 Global Warming Potential 100a will be applied to calculate the direct global warming potential of the system. Moreover, the inclusion of the agronomic valorization of the sludge will be analyzed to understand the potential in terms of avoided impacts.

Effects of substituting fish meal with Chlorella meal on growth performance, whole-body composition, pigmentation, and physiological health of marbled eel (Anguilla marmorata)

Chlorella meal is considered a promising alternative to fish meal in aquafeeds, but the effects of incorporating Chlorella meal as a feed ingredient on the growth and quality of eel have not been explored. The effects of partially substituting fish meal (0 %, 5 %, 10 %, 15 %, and 20 %) with Chlorella meal on the growth performance, whole-body composition, pigmentation, and physiological health of marbled eel (Anguilla marmorata) were evaluated in this study. The results revealed that dietary inclusion of Chlorella meal significantly increased the final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR), but it significantly decreased the feed conversion rate (FCR), with these parameters exhibiting linear trends (P < 0.05). The whole-body protein and fat contents were significantly higher in all groups fed with diets containing Chlorella meal compared to the control group (P < 0.05). In addition, the dorsal and abdominal skin of marbled eel exhibited an orange-yellow color, and the color intensity increased with increasing levels of dietary Chlorella meal. The color change corresponded to increased values of a* (redness), b* (yellowness), and lutein content in the fish skin (P < 0.05). The physiological health of marbled eel also improved in the groups where Chlorella meal was included. The optimal replacement rate was approximately 10 % (9 % Chlorella meal supplementation), because the whole-body protein content and most physiological health parameters were highest under this condition, and the growth performance did not show a significant increase when the fish meal replacement rate exceeded 10 % (P > 0.05). These findings indicate the potential of Chlorella meal as a promising alternative to fish meal in feed formulations, offering benefits in enhancing growth performance and quality of marbled eel.

Turning fishery waste into aquafeed additives: Enhancing shrimp enzymes immobilization in alginate-based particles using electrohydrodynamic atomization

Alternative protein ingredients are gradually replacing fish meal in aquafeeds. However, farmed animals often struggle to digest the provided feed, which leads to inefficient nutrient assimilation. This results in a high feed conversion ratio and in water quality deterioration. Fish waste-derived proteases show great potential as bioactive ingredients to enhance protein digestibility. To achieve this, a suitable carrier is essential to include exogenous proteases in the fish feed formulation. Therefore, this research aimed to immobilize a shrimp enzyme extract into different alginate-based microcapsules through electrodynamic atomization and compare their structural and functional properties. Morphology, physicochemical and thermal properties, and in vitro protein release were evaluated for the following microcapsules made from various materials: alginate (A), alginate-chitosan (AC), alginate-bentonite (AB), alginate-bentonite previously subjected to a sonication treatment (ABs), and a combination of all materials (ABsC or ABC). The average sizes ranged from 360 to 790 μm (wet) and 260–516 μm (freeze-dried), confirming the expected differences, with larger sizes for those including chitosan and bentonite. ABsC proved to be the most suitable system for immobilizing exogenous proteases, as these particles exhibited high encapsulation efficiency in both wet and freeze-dried versions and displayed controlled protein release under typical conditions of the proximal intestine. This was further confirmed through an in vivo trial. Two bioassays were conducted with tilapia (Oreochromis niloticus) (n = 42, 2.6 ± 0.58 g) to evaluate the distribution of ABsC-rodamine labeled particles in digestive organs and digestive enzyme activity. ABsC remained in the intestine for over 7 h, and a significant increase in total proteolytic activity was observed 60 min after feeding. These findings suggest that ABsC microcapsules could serve as effective carriers for exogenous proteases in feeds for aquaculture.

Assessment of Full-Fat Tenebrio molitor as Feed Ingredient for Solea senegalensis: Effects on Growth Performance and Lipid Profile.

Tenebrio molitor (TM) is considered as one of the most promising protein sources for replacing fish meal in aquafeeds, among other things because it is rich in protein, a good source of micronutrients and has a low carbon footprint and land use. However, the main drawback of TM is its fatty acid profile, in particular its low content of n-3 PUFA. This study evaluates the effects of partially replacing plant or marine-derived with full-fat TM meal at two different levels on growth performance and lipid profiles of Senegalese sole (Solea senegalensis). For this purpose, a control diet (CTRL) and four experimental isoproteic (53%) and isolipidic (16%) diets were formulated containing 5 and 10% TM meal replacing mostly fish meal (FM5 and FM10), or 10 and 15% TM meal replacing mostly plant meal (PP10 and PP15). Fish (215 g) were fed at 1% of their body weight for 98 days. The final body weight of fish fed the experimental diets containing TM meal was not different from that of fish fed the CTRL diet (289 g). However, the inclusion of TM meal resulted in a gradual improvement in growth rate and feed efficiency in both cases (replacement of fish or plant meals), and significant differences in specific growth rate (SGR) were observed between fish fed the CTRL diet (SGR = 0.30% day-1) and those fed diets with the highest TM meal content (PP15; SGR = 0.35% day-1). The experimental groups did not show any differences in the protein content of the muscle (19.6% w/w). However, significant differences were observed in the total lipid content of the muscle, with the FM10, PP10, and PP15 groups having the lowest muscle lipid contents (2.2% ww). These fish also showed the lowest neutral lipid content in muscle (6.6% dw), but no differences were observed in the total phospholipid content (2.6% dw). Regarding the fatty acid profile, fish fed FM10, PP10 and PP15 had lower levels of linoleic acid (18:2n-6) and higher levels of oleic acid (18:1n-9) in liver and muscle compared to fish fed CTRL. However, no differences were found between fish fed CTRL and TM-based diets for docosahexaenoic acid (22:6n-3) and total n-3 PUFA in liver and muscle. In conclusion, our study demonstrated that full-fat TM inclusion up to 15% in S. senegalensis diets had no negative effects or even some positive effects on fish survival, growth performance, nutrient utilization and flesh quality.

Utilization of Black Soldier Fly (Hermetia illucens) Larvae as a Potential Substitute for Fish Meal in the Production of Nile Tilapia (Oreochromis niloticus L.)

Utilization of quality aqua-feed relies heavily on fish meal sources of protein because of its nutritional balance. However, due to its limited supply, high cost, and decline of wild fish populations, aquaculture production has shifted focus to cheaper and more readily available alternatives to guarantee sustainable aquaculture productivity. Black soldier fly (Hermetia illucens) larvae are a promising replacement for fish meal in fish diets due to their relatively high crude protein, lipid and mineral contents, and the bioactive potential with anti-microbial, and other probiotic properties. This study determined the effect of partially replacing fish meal with black soldier fly meal (BSFLM) on the growth performance of Nile tilapia (Oreochromis niloticus). Four isonitrogenous (30% crude protein) diets in which fish meal protein was gradually substituted with BSFLM were prepared as follows: No BSFLM (control)-T0; 25% (BSFLM25)-T25, 50% (BSFLM50)-T50 and 75% (BSFLM75)-T75. The feeds were fed to the Nile tilapia fingerlings (mean weight 25 &amp;plusmn;5 g) which were randomly stocked in 12 cages at a stocking density of 30 fish per cage. The experimental fish were manually fed at 3% of the body weight for 28 days, and 4% of the body weight for 154 days twice a day. The study found that 25% and 50% replacement of fish meal protein with BSFLM resulted in the best growth performance of Nile tilapia, as measured by final mean body weight gain (BWG), specific growth rate (SGR), feed conversion ratio (FCR) and condition factor (K). This suggests that BSFLM is a promising alternative to fish meal in aqua-feeds in the production of Nile tilapia.

Sustainable Fish Feeds with Insects and Probiotics Positively Affect Freshwater and Marine Fish Gut Microbiota.

Aquaculture is the fastest-growing agricultural industry in the world. Fishmeal is an essential component of commercial fish diets, but its long-term sustainability is a concern. Therefore, it is important to find alternatives to fishmeal that have a similar nutritional value and, at the same time, are affordable and readily available. The search for high-quality alternatives to fishmeal and fish oil has interested researchers worldwide. Over the past 20 years, different insect meals have been studied as a potential alternate source of fishmeal in aquafeeds. On the other hand, probiotics-live microbial strains-are being used as dietary supplements and showing beneficial effects on fish growth and health status. Fish gut microbiota plays a significant role in nutrition metabolism, which affects a number of other physiological functions, including fish growth and development, immune regulation, and pathogen resistance. One of the key reasons for studying fish gut microbiota is the possibility to modify microbial communities that inhabit the intestine to benefit host growth and health. The development of DNA sequencing technologies and advanced bioinformatics tools has made metagenomic analysis a feasible method for researching gut microbes. In this review, we analyze and summarize the current knowledge provided by studies of our research group on using insect meal and probiotic supplements in aquafeed formulations and their effects on different fish gut microbiota. We also highlight future research directions to make insect meals a key source of proteins for sustainable aquaculture and explore the challenges associated with the use of probiotics. Insect meals and probiotics will undoubtedly have a positive effect on the long-term sustainability and profitability of aquaculture.

Effect of varied daily feeding intensities on growth performance and feed utilisation of South African dusky kob (Argyrosomus japonicus) juveniles reared in a recirculating aquaculture system

Several aquaculture studies have concluded that feed constitutes the heaviest cost in aquaculture enterprises. Consequently, researchers continue to investigate strategies that can lower feed costs such as the use of protein rich plant sources and insect meals to partially or completely substitute the expensive fishmeal in aquafeeds. However, this approach has often faced numerous challenges such as anti-nutrients in plant protein sources that limit their use and suboptimal polyunsaturated fatty acids profile in terrestrial protein sources such as insect meal. Precision feeding is a strategy that could also reduce aquafeed feed costs and enhance the economic sustainability of aquaculture. There is discordance regarding the feeding intensity that should be used for fish such as dusky kob. The current study was designed to compare the effect of three feeding intensities (2.8 %, 3.5 % and 4 % of body weight (BW)) on growth performance and feed utilisation of juvenile dusky kob (Argryrosomus japonicus). Dusky kob juveniles were randomly and evenly allocated to 18 tanks with a volume of 465 L. Each feeding intensity was randomly allocated to six tanks carrying 66 fish each. The average temperature and dissolved oxygen were 25°C and 5.5-6.0 mg/l, respectively. Commercial dusky kob diet was offered twice daily at the rate of 2.8%, 3.5% and 4% of body weight (BW). A feeding intensity × fish age (weeks) interaction effect was noted on fish feed intake (P&lt;0.05) but not on weight gain, feed conversion ratio (FCR), and specific growth rate (SGR). The overall weight gain after six weeks of feeding was similar across the three feeding intensities (P&gt;0.05). The 2.8% BW feeding rate promoted 1.06%/day SGR as compared to 1.21%/day and 1.48%/day for 3.5% and 4.0% BW feeding rates, respectively. Similar weight gains and FCR recorded across the three feeding intensities may suggest that the lowest feeding intensity (2.8% BW) should be used for dusky kob feeding to reduce feeding costs. Key words: Aquaculture, Feed, Dusky kob, Rations, Growth performance, FCR, RAS, SGR

Hermetia illucens for Replacing Fishmeal in Aquafeeds: Effects on Fish Growth Performance, Intestinal Morphology, and Gene Expression in the Zebrafish (Danio rerio) Model

For improving aquafeed sustainability, insect meal is currently considered the most promising alternative to fishmeal. However, in this regard, more data are still necessary to avoid possible negative impacts on fish growth performance, metabolism, and welfare. The present study investigated the effects of increasing the inclusion of Hermetia illucens meal (0%, 17%, 33% and 50% of the feed, equating to 0%, 34%, 66% and 100% fishmeal replacement) on fish mortality, growth performance, intestine morphology, and gene expression of intestinal carriers. The results showed no adverse effects on fish mortality, feed intake and body weight and a positive effect on feed conversion ratio. Body weight gain was higher when 17% and 50% of Black soldier fly meals’ feed included (34% and 100% fishmeal replacement, respectively). Gut morphology was not affected by the dietary treatments except for the area of PAS-positive goblet cells that was higher in the treatment fed 33% of insect meal. The mRNA expression of intestinal epithelium functionality-specific marker genes, such as slc15a1 (alias pept1, alias slc15a1b), gata4 and nfkb1b, confirmed that the insect meal-based diets might replace fishmeal-based diets without negative effects. Overall, the results of the present study suggest that using Hermetia illucens larvae meal as a replacement for fishmeal in aquafeeds might help to enhance sustainability while assuring favorable fish growth performance and gut health.

Fishmeal replacement by mealworm (Tenebrio molitor) in diet of farmed Pacific white shrimp (Litopenaeus vannamei): effects on growth performance, serum biochemistry, and immune response

Reducing the use of fishmeal (FM) in shrimp feed means significant savings in the amount of FM consumed globally and subsequently reducing production costs and environmental impacts. Insect meal (IM) is one of the protein sources to replace FM in aquafeeds. In this regard, this study was conducted with the aim of investigating the effect of replacing FM with mealworm (MW,Tenebrio molitor) on the growth performance, haemolymph biochemical responses, and innate immunity ofLitopenaeus vannamei. Shrimps with a mean weight of 7.41 ± 0.13 gram were cultured in 300-liter fiberglass tanks (with a useful drainage volume of 200 liters) with a density of 20 shrimp per tank over a period of 60 days. Dietary treatments, including the control treatment (no mealworm; T0), 15% (T15), 30% (T30), 60% (T60), and 100% (T100) level of replacing FM with mealworm (MW), each with three replications, were investigated in the form of a randomized design. The results of this study showed a significant difference in body weight gain (BWG), feed efficiency (FE), feed conversion ratio (FCR), and hepatopancreas index (HPI) among the treatments (P&lt; 0.05). With the increase of the replacement of FM with MW up to 30%, BWG, FE, and HPI were significantly increased then reduced. The levels of cholesterol (Chol), triglycerides (Tg), and glucose (Glu) showed a decreasing trend with increasing replacement of FM with MW and revealed a significant difference with the control treatment at high levels of replacement (P&lt; 0.05). Besides, the results showed that replacing FM with MW had a significant effect on the activities of superoxidase dismutase (SOD), phenol oxidase (PO), lysozyme (LZM), acid phosphatase (ACP), alkaline phosphatase (ALP) and the total count of hemocytes (THC) in the practical diets compared to the control group (P&lt; 0.05). Overall, the findings suggest that MW is a promising alternative protein source forL. vannamei, as it enhances both growth performance and the immune system. The study recommends the use of MW in the diet of farmed species in the aquaculture industry, given its lack of adverse impacts on growth performance and its potential to reduce environmental consequences resulting from its production. The results also underscore the importance of exploring alternative protein sources to reduce dependence on FM and enhance sustainability in the aquaculture industry.

Optimizing heterotrophic production of Chlorella sorokiniana SU-9 proteins potentially used as a sustainable protein substitute in aquafeed

Alternative protein sources for the reduction/replacement of fish meal in aqua-feeds are in urgent demand. Microalgae are considered sustainable protein sources for aquaculture due to their high-quality proteins with a complete profile of essential amino acids. This study examined the heterotrophic production of proteins from Chlorella sorokiniana SU-9. Culture parameters for maximal biomass and protein production are as follows: glucose – 10 g/L glucose, sodium nitrate – 1.5 g/L, and iron – 46 μM iron in BG-11 medium. Under optimal conditions, biomass content, protein content and protein productivity of SU-9 reached 4.14 ± 0.20 g/L, 403 ± 33 mg/g and 382 ± 36 mg/L/d, respectively. The protein profile of Chlorella sorokiniana SU-9 is comparable to fishmeal and soybean meal. The essential amino acids arginine, lysine and cysteine, along with glutamine and glutamate, were high. The production cost of SU-9 can be significantly reduced under heterotrophic cultivation conditions, making it a potential protein substitute in aquafeed.

Recent advances in the utilization of insects as an ingredient in aquafeeds: A review.

The aquafeed industry continues to expand in response to the rapidly growing aquaculture sector. However, the identification of alternative protein sources in aquatic animal diets to replace conventional sources due to cost and sustainability issues remains a major challenge. Recently, insects have shown tremendous results as potential replacers of fishmeal in aquafeed. The present study aimed to review the utilization of insects in aquafeeds and their effects on aquatic animals' growth and feed utilization, immune response and disease resistance, and fish flesh quality and safety. While many insect species have been investigated in aquaculture, the black soldier fly (Hermetia illucens), and the mealworm (Tenebrio molitor) are the most studied and most promising insects to replace fishmeal in aquafeed. Generally, insect rearing conditions and biomass processing methods may affect the product's nutritional composition, digestibility, shelf life and required insect inclusion level by aquatic animals. Also, insect-recommended inclusion levels for aquatic animals vary depending on the insect species used, biomass processing method, and test organism. Overall, while an appropriate inclusion level of insects in aquafeed provides several nutritional and health benefits to aquatic animals, more studies are needed to establish optimum requirements levels for different aquaculture species at different stages of development and under different culture systems.

Substitution of fish meal with Madagascar cockroach (Gromphadorhina portentosa) meal in diets for juvenile Nile tilapia (Oreochromis niloticus): effects on growth, nutrient assimilation, and nitrogen turnover rates.

Among the wide variety of alternative ingredients aimed to substitute fish meal in aquafeeds, insect meals have been recently proposed as novel, nutritionally good dietary components. In the present study, five isoproteic and isoenergetic experimental diets formulated with varying dietary levels of Madagascar cockroach meal substituting fishmeal on a dietary protein basis (0, 25, 50, 75, and 100%) were supplied to.Nile tilapia juveniles (Oreochromis niloticus) for 29days. Production parameters were compared among treatments, and the relative assimilation of the dietary nitrogen supplied by fishmeal and insect meal was estimated. To this end, nitrogen stable isotope analyses were applied to diets and fish muscle tissue. The isotopic changes elicited by the experimental ingredients were used to estimate the time required to reach isotopic equilibrium, the nitrogen turnover rates, and nitrogen residency times in muscle tissue. The latter were short and ranged from 4.7 to 6.2 d, except in diet containing 100% cockroach meal (7.8 d). No statistical differences were detected in final mean weight, specific growth, and survival rates among treatments. The relative proportions of dietary nitrogen and total dry matter supplied by insect and fish meal to growth were similar to the established dietary proportions after these were corrected for their respective apparent digestibility coefficients. The cockroach meal present in diets containing both main ingredients supplied relatively high proportions of dietary nitrogen (from 16 to 69%) to the biosynthesis of fish muscle tissue.

Fermented Soybean Meal (FSBM) in African Catfish (Clarias gariepinus) Diets: Effects on Growth Performance, Fish Gut Microbiota Analysis, Blood Haematology, and Liver Morphology.

The study revealed the potential of fermented soybean meal (FSBM) as a fish meal (FM) replacement in African catfish (Clarias gariepinus) feed formulation. Five isonitrogenous diets (32% crude protein) were prepared with five different levels of FSBM as FM replacement, namely 0% FSBM (T1), 40% FSBM (T2), 50% FSBM (T3), 60% FSBM (T4), and 70% (T5). The experimental fish was given the formulated diet for eight consecutive weeks. At the end of the feeding trial, the fish were subjected to growth performance, blood parameters, blood chemical, liver histology, and gut microbiota assessment. The study findings demonstrated that the experimental fish that received the T2 diet exhibited significantly higher (p &lt; 0.05) growth performance. Experimental fish that received diet T2 had significantly higher (p &lt; 0.05) white blood cell (WBC) and significantly lower (p &lt; 0.05) in terms of cholesterol (CHOL), albumin (ALB), globulin (GLOB), and total protein (TP). The replacement of FSBM to FM significantly affected liver morphology on the sinusoid, vacuole, nucleus, and erythrocytes. Gut microbiota composition analysis showed a significantly high abundance (p &lt; 0.05) of Akkermansia muciniphila in the experimental fish that received the T2 diet. The gut microbiota indicates that the experimental fish is in a healthy condition. In conclusion, replacing 40% FSBM with FM in aquafeed could enhance C. gariepinus growth performance and health conditions.

Interactions between intestinal morphology, digestion, inflammatory responses, and gut microbiota of juvenile channel catfish elicited by dietary enzymatic rice protein

The reduction of fishmeal in aquafeeds has been the concern of researchers. Replacing fishmeal with plant proteins affects intestinal function and inflammation, but the interaction between the intestinal responses and gut microbiota remains unclear. In this study, juvenile channel catfish (Ictalurus punctatus) was fed with four diets in which enzymatic rice protein (RP) replaced fishmeal at levels of 0 (FM), 2.5% (RP2.5), 5.0% (RP5.0), and 7.5% (RP7.5) for 8 weeks to solve the problem mentioned above. Quantification of intestinal morphology showed that 2.5% or 5.0% RP significantly increased villus length and goblet cell number, accompanied by higher activities of intestinal trypsin, alkaline phosphatase (AKP), and Na+/K+-ATPase (NKA) in RP2.5 group (P < 0.05). In contrast, 7.5% RP slightly damaged the intestinal mucosa and significantly reduced the activities of amylase, AKP, and NKA, as well as decreased serum complement 4 (C4) and immunoglobulin M (IgM). Noteworthy, RT-qPCR showed that 2.5% RP significantly down-regulated intestinal mRNA expression level of il8, while up-regulated mif, tlr4, tlr7, tgfβ3, and cldn2. In contrast, 7.5% RP up-regulated the mRNA expression levels of il1β, il8, and mif, while down-regulated cldn3d. Analysis of gut microbiota showed that 2.5% RP increased the relative abundance of Bacteroidetes and significantly activated potential functions of gut microbiota involved in carbohydrate metabolism. The 7.5% RP increased the diversity of the gut microbiota, accompanied by a significant increase in the relative abundance of conditionally pathogenic bacteria such as Vibrio, Serratia, and Aeromonas (classified as Proteobacteria). Notably, Vibrio was the biomarker species with the greatest difference between the FM and RP7.5 groups (genus level). Correlation analysis indicated that Vibrio may affect immunity through the C4 pathway and further lead to gut inflammation and digestive impairment. Taken above, these results indicated that RP could affect intestinal morphology, digestion, and inflammation, and interact with the composition and potential function of gut microbiota. The low RP supplement (2.5%) improved intestinal morphology and digestion, while high supplement (7.5%) disrupted gut microbiota homeostasis, resulting in damage to intestinal mucosa and inflammatory response.

Systematic review and meta‐analysis of production performance of aquaculture species fed dietary insect meals

AbstractThe present work employed a systematic review and meta‐analysis to quantify the overall effects of various types of insect meal on special growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) of aquatic animals. A total of 107 studies published from 1990 to 2021, targeting 23 freshwater and 17 marine fish species, employing 17 insect species as a replacement for fishmeal, was compiled. Overall, a significantly higher Hedges’ g value for SGR and lower FCR was found in aquatic animals fed dietary larval defatted mealworm Tenebrio molitor and pupal full‐fat silkworm Bombyx mori compared with fishmeal diet. The majority of dietary insect meals had a negative linear correlation with Hedges’ g of growth performance, except larval fly Chrysomya megacephala, which had a positive linear relationship, and of prepupal defatted black soldier fly Hermetia illucens, which had a negative quadratic relationship. Some insect meals, including G. bimaculatus, adult grasshoppers of Oxya fuscovittata and Zonocerus variegatus and larval full‐fat Cirina butyrospermi, supported adequate growth of aquatic animals at plausible inclusion levels. At as low as 2.2%, insect‐derived chitin supported growth performance and improved feed utilization of marine fish species. In the quest to minimize fishmeal in aquafeeds, insect meal holds enormous potential but is not the sole option; rather, integrating insect meal and novel/conventional materials is more strategic. The present study lays the groundwork for further multidisciplinary considerations for the effective use of insect meal as an alternative aquafeed protein with the goal of long‐term sustainability.

A Review on the Use of Distillers Dried Grains with Solubles (DDGS) in Aquaculture Feeds

Abstract Distillers dried grains with solubles (DDGS) to replace fishmeal (FM) or other plant protein sources and its effects on an aquatic animal’s growth performance and health system is rarely discussed. In recent times FM use in aquafeed has been a problem for the aquaculture industry because of the depletion of fish resources in the ocean and the high cost of FM. For that reason, researchers are focusing on reducing the cost of aquafeed production by lowering the inclusion of FM in aquafeed. One of the low-cost alternative protein sources to replace FM is DDGS. The present review discusses the compilation of available literature review and other works on the use of DDGS to replace FM in aquafeed and how it improves the growth performance, immune health system, and disease resistance in an aquatic animal. It focuses on the production of DDGS, the nutritional composition of DDGS, the chemical and physical characteristics of DDGS, and the effects of the DDGS inclusion in aquafeed on the aquatic animal. Apart from improving the growth performance of the aquatic animal when included in aquafeed, it also helps improve the immune health system of the animal. It also helps boost the immune system of the aquatic animal to fight diseases and increase disease resistance when included in aquafeed. Furthermore, DDGS also contains some constituents like carotenoids that help improve the meat quality of the animal when included in aquafeed. The current review also discusses the management and use of technology to improve the aquaculture industry, educate farmers on reducing diseases during the culturing periods, and increase productivity and profit in a friendly environment.

Digesta and Plasma Metabolomics of Rainbow Trout Strains with Varied Tolerance of Plant-Based Diets Highlights Potential for Non-Lethal Assessments of Enteritis Development.

The replacement of fishmeal in aquafeeds is essential to the sustainability of aquaculture. Besides the procurement of alternative protein sources, fish can also be selected for better performance on plant-based alternative diets. Rainbow trout (Oncorhynchus mykiss) is one such species in which the strain ARS-Sel has been selected for higher growth and enhanced utilization when fed soy-based diets. The aim of this study was to compare fish growth and plasma and digesta metabolomes between ARS-Sel and two commercial strains (CS-1 and CS-2), when fed plant-protein (PM) and fishmeal-based (FM) diets, and to correlate them with the onset of enteritis. An NMR-metabolomics approach was taken to assess plasma and digesta metabolite profiles. Diet and strain showed significant effects on fish growth, with the ARS-Sel fish receiving the PM diet reaching the highest final weight at sampling. Multivariate analysis revealed differences between plasma and digesta metabolite profiles of ARS-Sel and CS (CS-1 considered together with CS-2) PM-fed groups in the early stages of enteritis development, which was confirmed by intestinal histology. As reported in previous studies, the ARS-Sel strain performed better than the commercial strains when fed the PM diet. Our findings also suggest that metabolomic profiles of plasma and digesta, samples of which can be obtained through non-lethal methods, offer valuable insight in monitoring the occurrence of enteritis in carnivorous aquaculture species due to plant-based diets.

Interaction and effects of graded levels of dietary phytic acid on the moulting performance, whole body mineral composition and availability on the freshwater prawn Macrobrachium rosenbergii

The presence of anti-nutritional factors such as phytic acid (PA) in a number of potentially useful plant ingredients has been a major impediment to their use as replacements for fishmeal in aquafeeds. This study builds on an earlier studying investigating the growth performance and nutrient utilisation in the juvenile Malaysian giant river prawn, Macrobrachium rosenbergii exploring the effects and interactions of dietary PA with minerals on growth (somatic tissue). Additionally, the study set out to determine the changes in whole-body mineral composition and also on muscle tissues and the carapace, when different levels of PA were included within the diet. The hypothesis under test was that PA, as a mineral-binding agent by chelating di- and trivalent cations inhibits mineral availability. To explore this, effects of graded levels of PA (i.e. 0.26–control, 6.48, 11.28, 16.53, 21.45 and 26.16 g PA kg−1) on the moult frequency and mineral availability in juvenile M. rosenbergii (mean initial carapace length of 6.22 ± 0.52 mm; mean initial weight of 0.20 ± 0.01 g; n = 20 per replicate) fed over a period of 140 days were determined. The levels of PA assessed in this feed trial had no major detrimental effects on moult frequency. Negative effects (p < 0.05) of high PA levels (i.e. 21.45–26.16 g PA kg−1), however, were found on the whole-body phosphorus concentration. An increasing trend, although not significantly so, was recorded for the calcium content in the whole-body and carapace with increasing PA inclusion. Significant changes (p < 0.05) were observed in the levels of zinc, copper, potassium and sodium in the carapace, particularly in the prawns fed the diet containing 11.28 g PA kg−1, which suggests that the specific minerals were either selectively utilised or retained in the carapace. These changes may have a serious impairment hence caution should be exercised to ensure that the anti-nutritive effects of PA are minimised.

In situ fatty acid production supports shrimp yields in diets lacking fish oil and fishmeal

Using capture fishery-derived fish oil and fishmeal in aquafeeds is unsustainable. This study mimicked semi-intensive shrimp ponds, including primary producers, in mesocosm tanks. Fatty acid mass balances were computed to distinguish between diet-based and primary production-based LC-PUFA contributions to shrimp (Litopenaeus vannamei) production and meat quality. Performance and body fatty acid composition were compared of shrimp fed a commercial diet containing fish oil and fishmeal (control), with a fishmeal- and fish oil-free diet (low LC-PUFA diet: LOW). Six mesocosms were each stocked with 60 juvenile shrimp and randomly assigned to the two diets. After an 8-week grow-out period, biomass production, survival and proximate body composition were similar between diets. Control shrimp contained twice as much LC-PUFA and omega-3 fatty acids than LOW shrimp. Large quantitative losses (85%) were found in both treatments of the LC-PUFA-precursors alpha-linolenic acid (ALA) and linoleic acid (LA) that were being used as energy source by the shrimp instead for LC-PUFA synthesis. Whereas losses were also observed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the control group, there was a gain for these components in the LOW tanks. LOW shrimp sourced at least 32% of their total EPA gain and 15% of their total DHA gain from the algal-based food web. This quantitative analysis of the fate of major dietary fatty acids strongly suggests that the pond's primary production can provide shrimp additional LC-PUFA. Finding a balance between LC-PUFA contribution through formulated feed and natural production seems possible and deserves further research.

Effect of a phytogenic feed additive on the growth performance and immunity of Pacific white leg shrimp, Litopenaeus vannamei, fed a low fishmeal diet

AbstractPlant‐derived products have been suggested to partially replace fishmeal in aquafeed; however, often at decreased growth performance, inflammatory responses, and increased susceptibility to diseases. This study assessed the effects of the commercial phytogenic feed additive Digestarom PEP MGE on the growth, nutritional performance, and immune response of L. vannamei. Juvenile shrimp (N = 540) were stocked in 36 tanks (V = 100 L) for 63 days and fed one of the four experimental diets: (i) standard formulation (control, 24% fishmeal), (ii) low fishmeal diet (5%), (iii) low fishmeal diet plus 0.2 g/kg Digestarom PEP MGE, and (iv) low fishmeal diet plus 0.4 g/kg Digestarom PEP MGE. The results obtained after 63 days of feed supplementation suggest that the blend of essential oils tested compensated for the negative performance and health consequences of the low fishmeal diet. Particularly, the survival, FCR, total hemocyte count, and respiratory burst of the shrimp fed a low fishmeal diet supplemented with this phytogenic improved up to the levels recorded for shrimp fed a high fishmeal diet. Overall, results suggest that Digestarom PEP MGE can be incorporated into shrimp low fishmeal diets to compensate for the negative performance and immunological effects of partially replacing fishmeal with plant‐based protein.