Fish Feed Research Articles

Europium Nanoparticle-Based Lateral Flow Strip Biosensors for the Detection of Quinoxaline Antibiotics and Their Main Metabolites in Fish Feeds and Tissues.

Olaquindox (OLA) and quinocetone (QCT) have been prohibited in aquatic products due to their significant toxicity and side effects. In this study, rapid and visual europium nanoparticle (EuNP)-based lateral flow strip biosensors (LFSBs) were developed for the simultaneous quantitative detection of OLA, QCT, and 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in fish feed and tissue. The EuNP-LFSBs enabled sensitive detection for OLA, QCT, and MQCA with a limit of detection of 0.067, 0.017, and 0.099 ng/mL (R2 ≥ 0.9776) within 10 min. The average recovery of the EuNP-LFSBs was 95.13%, and relative standard deviations were below 9.38%. The method was verified by high-performance liquid chromatography (HPLC), and the test results were consistent. Therefore, the proposed LFSBs serve as a powerful tool to monitor quinoxalines in fish feeds and their residues in fish tissues.

Astaxanthin Supplementation as a Potential Strategy for Enhancing Mitochondrial Adaptations in the Endurance Athlete: An Invited Review.

Astaxanthin, a potent antioxidant found in marine organisms such as microalgae and krill, may offer ergogenic benefits to endurance athletes. Originally used in fish feed, astaxanthin has shown a greater ability to mitigate various reactive oxygen species and maintain the structural integrity of mitochondria compared to other exogenous antioxidants. More recent work has shown that astaxanthin may improve: (1) cycling time trial performance, (2) cardiorespiratory measures such as submaximal heart rate during running or cycling, (3) recovery from delayed-onset muscle soreness, and (4) endogenous antioxidant capacity such as whole blood glutathione within trained populations. In this review, the history of astaxanthin and its chemical structure are first outlined before briefly describing the various adaptations (e.g., mitochondrial biogenesis, enhanced endogenous antioxidant capacity, etc.) which take place specifically at the mitochondrial level as a result of chronic endurance training. The review then concludes with the potential additive effects that astaxanthin may offer in conjunction with endurance training for the endurance athlete and offers some suggested practical recommendations for athletes and coaches interested in supplementing with astaxanthin.

Gyrodactylus in the spotlight: how exposure to light impacts disease and the feeding behavior of the freshwater tropical guppy (Poecilia reticulata).

Artificial light at night (ALAN) negatively impacts organisms in many ways, from their feeding behaviors to their response and ability to deal with disease. Our knowledge of ALAN is focused on hosts, but we must also consider their parasites, which constitute half of all described animal species. Here, we assessed the impact of light exposure on a model host-parasite system (Poecilia reticulata and the ectoparasitic monogenean Gyrodactylus turnbulli). First, parasite-free fish were exposed to 12:12 h light:dark (control) or 24:0 h light:dark (ALAN) for 21 days followed by experimental infection. Second, naturally acquired G. turnbulli infections were monitored for 28 days during exposure of their hosts to a specified light regime (6:18 h, 12:12 h, or 24:0 h light:dark). Experimentally infected fish exposed to constant light had, on average, a greater maximum parasite burden than controls, but no other measured parasite metrics were impacted. Host feeding behavior was also significantly affected: fish under ALAN fed faster and took more bites than controls, whilst fish exposed to reduced light fed slower. Thus, ALAN can impact parasite burdens, even in the short term, and altering light conditions will impact fish feeding behavior. Such responses could initiate disease outbreaks or perturb food-webs with wider ecological impacts.

Study of the influence of fish feeding on the example of carp (Cyprinus carpio L.) under conditions of chemical pollution of the aquatic environment

The study of the influence of chemicals in the aquatic environment on the nutrition of fish, which lead to gradual pollution of the aquatic environment and violation of living conditions, and the development of methods for improving the nutritional properties of fish, which is an important branch of science that combines fish biology, in-depth study of nutrition and rational management, has been established fish resources and environmental sustainability. In recent years, a significant amount of research has been conducted aimed at understanding the relationships between fish nutrition, their development and the quality of fish products, the influence of chemicals on these processes in today's conditions using the example of carp (Cyprinus carpio L.). Analyzing the data, it was found that the quality of fish nutrition depends on the quality and composition of water, which affects the growth, development and health of fish. Considering the requirements of nutrients such as proteins, fats, vitamins and minerals, good nutrition can improve the quality of fish production. Special attention is paid to the role of proteins in the metabolism of fish using the example of cyprinus carp (Cyprinus carpio L.), growth and development, as well as adaptation to the interesting study of the composition of tissue proteins of carp during cadmium and lead intoxication. This year's carp (Cyprinus carpio L.), which is a widespread object of pond culture in Ukraine, was used for the experiment. A detailed analysis indicates that taking into account the effect of toxic substances on fish nutrition is necessary to ensure their health and optimal fish production. The development of new feeding strategies and the use of special additives is becoming a key aspect not only for improving the quality of products, but also for ensuring compliance with safety standards and environmental sustainability in the field of aquaculture and fisheries. Such research identifies new ways to create sustainable and healthy fish populations, contributing to the coordinated development of the agro-industrial sector and the preservation of aquatic ecosystems.

Loss of Gcn2 exacerbates gossypol induced oxidative stress, apoptosis and inflammation in zebrafish

Gossypol, a naturally occurring compound found in cottonseed meal, shows promising therapeutic potential for human diseases. However, within the aquaculture industry, it is considered an antinutritional factor. The incorporation of cottonseed meal into fish feed introduces gossypol, which induces intracellular stresses and hinders overall health of farmed fish. The aim of this study is to determine the role of General control nonderepressible 2 (gcn2), a sensor for intracellular stresses in gossypol-induced stress responses in fish. In the present study, we established two gcn2 knockout zebrafish lines. A feeding trial was conducted to assess the growth-inhibitory effect of gossypol in both wild type and gcn2 knockout zebrafish. The results showed that in the absence of gcn2, zebrafish exhibited increased oxidative stress and apoptosis when exposed to gossypol, resulting in higher mortality rates. In feeding trial, dietary gossypol intensified liver inflammation in gcn2−/− zebrafish, diminishing their growth and feed conversion. Remarkably, administering the antioxidant N-acetylcysteine (NAC) was effective in reversing the gossypol induced oxidative stress and apoptosis, thereby increasing the gossypol tolerance of gcn2−/− zebrafish. Exposure to gossypol induces more severe mitochondrial stress in gcn2−/− zebrafish, thereby inducing metabolic disorders. These results reveal that gcn2 plays a protective role in reducing gossypol-induced oxidative stress and apoptosis, attenuating inflammation responses, and enhancing the survivability of zebrafish in gossypol-challenged conditions. Therefore, maintaining appropriate activation of Gcn2 may be beneficial for fish fed diets containing gossypol.

Electromyographic Analysis of Upper- and Lower-extremity Muscles in Adults during Agro-healing Activities

This study investigated the activity of upper- and lower-extremity muscles for 15 agricultural tasks of agro-healing. For the development of an agro-healing program using farm resource types, 15 selected agro-healing activities (namely, digging, raking, fertilizing, planting transplants, tying plants to stakes, watering, harvesting, washing, cutting, cooking, collecting natural objects, decorating natural objects, interacting with dogs, walking dogs, and feeding fish) were extracted and performed in a total of 21 adults (average age: 42.29 ± 14.76 years) at D Care Farm in Cheongju, Korea, from June to July 2022. Before these activities, informed consent was obtained from participants and muscle activity of the upper and lower extremities was measured. Muscle activation during activity performance was measured using electromyography (EMG), and the rating of perceived exertion for each activity was investigated. Bipolar surface EMG electrodes were attached at 16 locations on the left and right upper-extremity muscles (anterior deltoid, biceps brachialis, brachioradialis, and flexor carpi ulnaris) and lower-extremity muscles (vastus lateralis, vastus medialis, biceps femoris, and gastrocnemius). The results indicated that the activity of the lower-extremity muscles was higher than that of the upper-extremity muscles during 15 agricultural activities. During plant-mediated activity and animal-assisted activities, the rate of right muscle use was higher than that of left muscle use among the upper-extremity muscles, whereas the rate of right and left muscle use showed a similar tendency among the lower-extremity muscles. During plant-mediated activities, agricultural activities involving the use of heavy tools highly activated the right forearm muscle (flexor carpi ulnaris), whereas holding and interacting with animals highly activated the left forearm muscles (biceps brachialis, brachioradialis, and flexor carpi ulnaris). It is expected that the EMG data obtained in this study can be used as basic biomechanical data when designing an agro-healing program to improve physical function.

Some recent advancements in fish nutrition and feed technology in India

The advancements in fish nutrition outlined here provide a promising picture of a thriving and sustainable aquaculture industry. By embracing these innovations, exploring alternative ingredients, optimising nutrient utilisation, and tailoring feed strategies to specific systems, we can confidently navigate the future of seafood production, ensuring food security for generations to come while safeguarding the health of our planet. In the pursuit of sustainable aquaculture, researchers have focused on eco-friendly nutritional strategies, aiming to minimize environmental impact and conserve natural resources. Nutrient recycling, a fundamental concept in sustainable aquaculture, involves utilizing fish waste as organic fertilizer for plant crops resulting in a circular economy and reducing the carbon footprint. . KEYWORDS :Fish Nutrition, Feed Technology, Recent Advancement

Development of gadgets and systems in plastic for use in freshwater aquaculture

The usage of plastics has transformed the agricultural production sector and has great impactin improving the overall scenario in all production systems including fisheries and aquaculture.Nylon fishnets, components of RAS, aquaponics and biofloc (BF)systems, plastic pipe framed nylon net cages, pen culture in water locked areas, etc. are some of the important uses of plastics in aquaculture. The AICRP on PEASEM, ICAR-CIFA, Bhubaneswar Centre is working since its inception in 1988 and contributed several plasticulture technologies and products for the development of aquaculture systems and processes (APA/CIFA 1988-2005; Mohapatra et.al., 2003, 2011 and 2016). The design and fabrication of the plastic gadgets and systems have been done considering the biological requirements of the aquaculture. The developed technologies are fully or partially adopted and accepted by the farming communities of the country. The paper presents some of the developed gadgets and systems that are presently in use in aquaculture in the country. Those are portable FRP carp hatchery having capacity of 1.0-1.2 million spawn production per cycle; portable FRP magur hatchery for incubation of 50,000 eggs per cycle; portable FRP pabda hatchery for production of 25,000-30,000 early fry per operation; different types of fixed and floating cages; live fish transportation tank of 1200l capacity which can be transported in a jeep trailer, power trailer or trolley; FRP silos of different sizes for fish rearing; feeders of different types such as demand, semiautomatic and automatic for fish feeding; plastic covered ponds for raising fishes in winter season; floating nursery for fish seed and aquaponics.. KEYWORDS :Modern farming Technique, Gedgets Plastic, Aquaculture

Effect of Solid-State Fermentation on Phytochemical and Proximate Composition of Millet Bran Meal

The majority of a fish farm's overall operating expenses involve costs related to feeds. Commercial feeds are often too expensive for fish farmers. Consequently, farmers do use agricultural by-products and locally available fish feed ingredients to improve pond productivity and minimise cost. This study was aimed at evaluating the effects of solid-state fermentation on phytochemical components and proximate composition of millet bran meal for possible incorporation in fish feed production. Millet bran was collected in three different bowls, ground to powder, and then sieved and fermented using a solid-state fermentation procedure. Each sample was fermented (wet at 10% moisture and kept in a container at ambient temperature) for 24 hours (1 day), 96 hours (4 days), and 168 hours (7 days). Afterwards, the fermented samples were sun-dried for 94 hours (4 days approximately). Quantitative phytochemical screening was carried out on the samples which were analysed for proximate composition. The results revealed that fermenting millet bran for seven days (168hrs) using solid-state fermentation method reduced the alkaloid content from 14.69±1.24 to 10.12±0.16, phytate from 5.73±1.32 to 3.25±0.73, tannins from 6.62±0.53 to 4.62±0.84, oxalate from 17.78±1.65 to 13.82±0.53. However, it increases flavonoids from 11.95±1.82 to 13.08±1.35 and phenols from 23.78±1.65 to 31.71±0.62. The study also elucidates an increase in crude protein from 9.23±0.64 to 19.77±0.53 and a reduction in crude fibre from 7.41±0.52 to 6.02±1.14. This study demonstrates that solid-state fermented millet bran meal can be incorporated as an essential part of feed production.

THE EFFECTIVENESS OF MAGGOT (Hermetia illucens) AS CATFISH FEED IN AQUAPONIC FARMING SYSTEMS

The nutritional composition of maggots can be utilized as a substitute for pellets to reduce the cost of purchasing fish feed through an aquaponic system integrated with spinach plants. This study aimed to determine the effectiveness of maggots as catfish feed in an aquaponic farming system. The study was conducted from February to July 2021 at the Agroecotechnology Experimental Farm of Trilogy University, Jakarta. Meanwhile, maggot proximate testing was carried out at the Center for Agro Industry, Bogor, West Java. The experiment employed a one-factor Randomized Group Design (RAK) (catfish feed) with three levels: pellets (P0), maggot (P1), and a combination of pellets and maggot (P2). The results showed that using maggot as a substitute for catfish feed in the aquaponic system was considered effective because the weight and length of catfish harvested were as good as those fed with pellets. However, the growth of spinach plants integrated with catfish through the aquaponic system is still not optimal compared to conventional cultivation in general. Nevertheless, the growth results were still better than those integrated with catfish fed with pellet or combination feed. The spinach growth results indicated that the plant had a height of 18.20 cm, a total of 6.14 strands of leaves, a stem diameter of 2.25 mm, a root length of 35.51 cm, and a weight of 20.97 grams.

Selenium‐chitosan engineered nanocomposite as efficient formulated fish diet evaluated for sustainable aquaculture practice of Oreochromis niloticus (Nile tilapia) fishes

AbstractOreochromis niloticus a Nile tilapia fish is widely used for fish culture practice in many countries for its easy acclimatization and high yield at a short pace of time. Selenium‐chitosan (SeCh) nanoparticles are efficiently used in agriculture, medicine, and aquaculture practices in several studies. The significant approach of Selenium‐Chitosan incorporated fish feed will be evaluated in the present study to achieve the better aquaculture practice in future. In the present study, SeCh nanoparticle was chemically synthesized and incorporated with formulated fish feed. Selenium formulated fish feed contains 31.49 g of carbohydrates and 41.52 g of proteins. SeCh‐fed O. niloticus fingerlings exhibited significantly increased specific growth rates in terms of weight gain, and feed conversion ratio. Chemical characterization of SeChNPs through FTIR spectroscopy indicates the presence of an adjuvant combination of selenium and chitosan presence through functional groups of COO stretch, CH, CC, and CN stretch representing at 3226, 2878, and 1734 cm−1, respectively. Scanning electron microscopy (SEM) and EDX analysis revealed the structural properties of SeChNPs as a fibrous pattern that contains Carbon, Oxygen, and Selenium elements as predominant peak values. SeChNPs incorporated fish feed has higher protein content which is a standard hallmark for a fish feed and an essential prerequisite for fish growth. The formulated SeCh fish feed in the present study is an innovative approach which can be taken further for higher level testing and processing for developing as a better fish feed in terms of feasible and efficient fish growth enhancer.

Antibacterial and gut health effects of Amomum tsao-ko in aquatic feed: A sustainable alternative to chemical antibiotics.

Amomum tsao-ko Crevost et Lemarie (Zingiberaceae), an aromatic plant, has been considered to have diverse medicinal values and economic significance. It has been reported to possess antibacterial, antioxidant, and antidiabetic effects. With the increasing risk of diseases in aquaculture, there is a need for alternative solutions to chemical antibiotics. Plant extracts have shown promise as natural feed additives for aquatic animals. In this study, the antibacterial effect of Amomum tsao-ko crude extracts was evaluated using the Oxford cup method. The extracts exhibited significant antimicrobial activity against Salmonella typhimurium and Salmonella enteritidis. Furthermore, the addition of Amomum tsao-ko to fish feed resulted in notable changes in the gut structure of zebrafish and tilapia. The length and morphology of intestinal villi were enhanced, promoting improved digestion. Analysis of the gut microbial community revealed that Amomum tsao-ko supplementation induced key changes in the gut microbial community composition of both zebrafish and tilapia. Notably, a 1% inclusion of Amomum tsao-ko resulted in a marked rise in Proteobacteria levels in zebrafish, which diminished at 10% dosage. The supplement elicited mixed reactions among other bacterial phyla like Actinobacteria and Verrucomicrobiota. Fluctuations were also observed at the genus level, pointing to the concentration of Amomum tsao-ko playing a pivotal role in influencing the structure of intestinal bacteria. The findings of this study suggest that Amomum tsao-ko has antibacterial properties and can positively influence the gut health of fish. The potential use of Amomum tsao-ko as a natural feed additive holds promise for improving aquaculture practices and reducing reliance on chemical antibiotics. Further research is needed to explore the full potential and applications of Amomum tsao-ko in fish feed development.

How do fish consume microplastics? An experimental study on accumulation pattern using Nile tilapia (Oreochromis niloticus).

The aim of this study was to investigate microplastic (MP) exposure by Nile tilapia (Oreochromis niloticus) in laboratory conditions. A total of 150 tilapia fishes were equally distributed randomly in 15 different glass tanks with five experimental conditions. Observed results depicted that the presence of MPs in different organs was mainly accumulated from the fish feed rather than externally added MPs in the culture tanks. It was also revealed that the gastrointestinal tract (GIT) was found to be the most susceptible to MPs accumulation followed by gills and muscles in order. However, muscle contained the least size of MPs followed by GITs and gills. A statistical test showed significant correlations among the average length and weight of fish with MP exposure. A filamentous shape was found to be dominant in both GITs and gills while fragment shape was dominant in muscles. FTIR results revealed a total of 12 different polymers in the fish of which two polymers (polyvinyl alcohol and ethylene vinyl acetate) were not detected in the feed-only tanks. Polypropylene (PP) and polyethylene terephthalate (PET) were found to be dominant polymers in all the experimental GIT, gills, and muscle organs. FESEM results indicated the presence of different textures including cracks, edges, flakes, scratches, grooves, and adhering particles. EDX results exhibited the presence of Na, Si, K, Ni, Cu, Zn, As, and Cd in the analyzed samples that may pose additional health risks. Thus, this study could act as baseline data for laboratory-based studies of aquaculture species in future research.

Sustainable Fish Feed: A Comprehensive Life Cycle Analysis

The concept of sustainability is used as an interpretation in terms of three dimensions - environmental, economic, and social dimensional balance. Several methodologies and tools have been developed to enable sustainability assessment in different sectors and different scales. To assess sustainability, it is necessary to clearly define the system and its elements and to select the appropriate indicators. Each method has advantages and disadvantages, but combining several methods can help overcome a weakness. The aquaculture sector continues to grow all over the world and therefore, to reduce the impact of the sector, it is necessary to evaluate reasonable alternatives. The aim of the study is to evaluate several fish feed compositions according to environmental parameters using life cycle analysis (LCA), for economic parameters using life cycle costs (LCC), for social parameters using social life cycle analysis (S-LCA), as well as comparing technical parameters. The result is an evaluation of fish feed considering several dimensions, to benefit the fish from this feed, as well as to reduce the impact on the environment from the production of feed.

Evaluation of Aflatoxins and Heavy Metals Exposure in the Local Feeds of Fish and Shrimp in Bangladesh.

This study aims to comprehensively assess the presence of aflatoxins, pervasive fungal toxins, and heavy metals (lead, chromium, cadmium) in the local feed of fish and shrimp. Forty-eight samples of the fish and shrimp feed were collected from the Dhaka and Sathkhira districts of Bangladesh respectively. Aflatoxins (B1, B2, G1, G2) were analyzed by high-performance liquid chromatography (HPLC) with fluorescence detector, and atomic absorption spectrophotometry (AAS) was used for the heavy metal detection after sample digestion. The standard analytical methods of the Association of Official Analytical Chemists were followed for analyzing the proximate composition of the feed samples. The findings revealed the high toxic concentration of total aflatoxins particularly in fish feed (196.25 μg/kg). Concurrently, varying concentrations of heavy metals, including lead (Pb) and chromium (Cr), were detected, with the highest levels found in shrimp feed at 3.324 and 174.6 mg/kg, respectively. In comparison, highest contamination of cadmium (Cd) was found in fish feed at 0.398 mg/kg. The outcomes are growing concerns regarding the quality of locally sourced feed and emphasizing the need for prompt corrective actions. Otherwise, neglecting this concern may lead to the possibility of both fish and, ultimately, humans who consume them being vulnerable to the absorption and accumulation of these assessed toxic compounds.

Fish feeding rate affects the productive performance of whiteleg shrimp and lebranche mullet integrated culture using biofloc technology

Fish feeding rate affects the productive performance of whiteleg shrimp and lebranche mullet integrated culture using biofloc technology

Application of Cystoseira myrica phycosynthesized selenium nanoparticles incorporated with nano-chitosan to control aflatoxigenic fungi in fish feed.

The recurrent contaminations of feed materials with mycotoxigenic fungi can endanger both farmed animals and humans. Biosynthesized nanomaterials are assumingly the ideal agents to overcome fungal invasion in feed/foodstuffs, especially when utilizing sustainable sources for synthesis. Herein, the phycosynthesis of selenium nanoparticles (SeNPs) was targeted using Cystoseira myrica algal extract (CE), and the conjugation of CE/SeNPs with chitosan nanoparticles (NCt) to produce potential antifungal nanocomposites for controlling Aspergillus flavus isolates in fish feed. The phycosynthesis of SeNPs with CE was effectually carried out and validated using visible/UV analysis, X-ray diffraction and transmission microscopy; CE/SeNPs had diameters of 8.7 nm and spherical shapes. NCt/CE/SeNPs nanocomposite (173.3 nm mean diameter) was achieved and the component interactions were validated via infrared spectroscopic analysis. The antifungal assessment of screened nanomaterials against three Aspergillus flavus strains indicated that NCt/CE/SeNPs exceeded the fluconazole action using qualitative/quantitative assays. Severe alteration/distortions in A. flavus mycelial structure and morphology were microscopically observed within 48 h of NCt/CE/SeNPs treatment. The treatment of feed ingredients (crushed corn and feed powder) by blending with nanomaterials (NCt, CE/SeNPs and NCt/CE/SeNPs) led to significant reduction in A. flavus count/growth after storage for 7 days; NCt/CE/SeNPs could completely inhibit any fungal growth in feed material. The pioneering phycosynthesis of CE/SeNPs and their nanoconjugation with NCt generated bioactive antifungal agents to control A. flavus strains. The innovatively constructed NCt/CE/SeNPs nanocomposite is advised for application as an effectual, biosafe and natural fungicidal conjugate for the protection of fish feed from mycotoxigenic fungi. © 2024 Society of Chemical Industry.

БАЛЫҚ ДЕРНӘСІЛДЕРІН ӨСІРУ ҮШІН ОҢТАЙЛЫ ҚОРЕК РЕСУРСЫ РЕТІНДЕ АРТЕМИЯЛАРДЫ ӨНДІРУ

In aquaculture, the use of Artemia as an optimal nutrient resource for fish fry is an object of growing interest. The advantages of using Artemia include the possibility of mass cultivation under controlled conditions, the possibility of long-term storage in frozen form and resistance to external environmental conditions. Artemia, belonging to crustaceans, is a rich source of protein, fat, vitamins and minerals necessary for the healthy development of fish larvae. Due to the high content of unsaturated fatty acids, omega-3 and omega-6, fry contribute to the development of a healthy immune system, which reduces the risk of many diseases. Their small size and mobility make them available for cultivation, which ensures a high level of quality and reduces feed consumption. The results of the study show that the use of crustaceans as the main food source for fish farming contributes to improving the life, growth and health of fry. This makes them a successful type of feed in aquaculture and an optimal resource for fish farming. Further research in this area can lead to increased efficiency of fish farming, development of practices and improvement of the overall potential of the aquaculture industry. This article discusses the advantages of using Artemia, its biological value, ease of cultivation and versatility in the nutrition of various fish larvae. Various methods and technologies of growing Artemisia are analyzed, as well as their application in breeding species of fish larvae. Special attention is paid to optimizing the maximum growth of fish larvae and feeding conditions.

Effect of Scoparia dulcis Extract on Lipid Oxidation in Fish Feed, Growth Performance, and Hypoxia Tolerance in Juvenile Jian Carp (Cyprinus carpio var. Jian)

Lipid oxidation and hypoxia can lead to oxidative damage in aquatic animals. This study explored the effects of Scoparia dulcis extracts (SDE) on lipid oxidation, fish growth performance, digestive ability, antioxidant capacity, and hypoxia tolerance ability. The results showed that SDE decreased malonaldehyde (MDA), conjugated diene (CD), and peroxide value (PO) in the linoleic acid and linolenic acid as well as in fish feed. Broken-line analysis revealed that the optimal acetone extract of S. dulcis (AE) supplements was 4.02, 4.01, and 4.01 g kg−1 determined from PO, CD, and MDA, respectively. Dietary AE supplementation increased feed intake and specific growth rate and activities of amylase, trypsin, and lipase as well as alkaline phosphatase in fish hepatopancreas and gut. Polynomial regression analysis showed that optimal dietary AE supplement was 3.61 g kg−1 diet determined from weight gain. Furthermore, dietary AE supplementation decreased MDA content and increased glutathione content and the activities of glutathione peroxidase, catalase, superoxide dismutase, and glutathione reductase in fish digestive organs, gills, erythrocytes, and muscle. Dietary AE supplementation increased durative time (DT) and oxygen consumption rate (OCR) under hypoxia condition. Based on polynomial regression analysis, optimal dietary AE supplements were 4.73 and 4.60 g kg−1 diet determined from DT and OCR for hypoxia tolerance in fish, respectively. According to our current research, SDE’s antioxidant capacity may be attribute to their phenolic chemicals.

A novel family of defensin-like peptides from Hermetia illucens with antibacterial properties.

The world faces a major infectious disease challenge. Interest in the discovery, design, or development of antimicrobial peptides (AMPs) as an alternative approach for the treatment of bacterial infections has increased. Insects are a good source of AMPs which are the main effector molecules of their innate immune system. Black Soldier Fly Larvae (BSFL) are being developed for large-scale rearing for food sustainability, waste reduction and as sustainable animal and fish feed. Bioinformatic studies have suggested that BSFL have the largest number of AMPs identified in insects. However, most AMPs identified in BSF have not yet undergone antimicrobial evaluation but are promising leads to treat critical infections. Jg7197.t1, Jg7902.t1 and Jg7904.t1 were expressed into the haemolymph of larvae following infection with Salmonella enterica serovar Typhimurium and were predicted to be AMPs using the computational tool ampir. The genes encoding these proteins were within 2 distinct clusters in chromosome 1 of the BSF genome. Following removal of signal peptides, predicted structures of the mature proteins were superimposed, highlighting a high degree of structural conservation. The 3 AMPs share primary sequences with proteins that contain a Kunitz-binding domain; characterised for inhibitory action against proteases, and antimicrobial activities. An in vitro antimicrobial screen indicated that heterologously expressed SUMO-Jg7197.t1 and SUMO-Jg7902.t1 did not show activity against 12 bacterial strains. While recombinant SUMO-Jg7904.t1 had antimicrobial activity against a range of Gram-negative and Gram-positive bacteria, including the serious pathogen Pseudomonas aeruginosa. We have cloned and purified putative AMPs from BSFL and performed initial in vitro experiments to evaluate their antimicrobial activity. In doing so, we have identified a putative novel defensin-like AMP, Jg7904.t1, encoded in a paralogous gene cluster, with antimicrobial activity against P. aeruginosa.