Fish Meal Research Articles

Rethinking Freshwater Cage Aquaculture: A Case in Ghana

Lakes around the world, including Ghana’s Lake Volta, are facing insidious threats from pollutants due to high dependency on aquatic ecosystems. Cage aquaculture is expanding across Africa because of its potential to address food insecurity, provide livelihoods, and boost local economies. However, the uncontrolled expansion of cage aquaculture can have significant negative impacts on water resources, including environmental footprints that threaten biodiversity. Given the intensification of cage aquaculture for tilapia farming on Lake Volta, we advocate for a transition to inland-integrated aquaculture systems that promote circularity. Strengthening stakeholder collaboration is essential for enhancing competence in mapping inland aquaculture areas, identifying eco-friendly alternatives and reinforcing aquaculture regulations, with particular emphasis on cage culture on Lake Volta. These strategies can reduce the pressures imposed by tilapia cage farms on the lake while promoting best management practices. Additionally, capacity building must be an ongoing process to address knowledge gaps, including the development of effective preparedness plans executed during emergencies. The ongoing pollution from illegal mining in the Black Volta River, a tributary of Lake Volta, along with endemic diseases in the lake, further compounds fish health and welfare issues. This underscores the urgent need to implement inland transition strategies to protect the lake, mitigate disease spread, and ensure safe fish food production.

Evaluating Inclusion of Commercial Pistachio By-Product as a Functional Ingredient in Rainbow Trout Fishmeal and Plant Meal-Based Diets

To meet the growing demand for sustainable aquaculture, plant proteins are being explored as alternative sources in fish diets. However, some plant proteins can have adverse health effects on fish, prompting research into functional feed ingredients to mitigate these issues. This study investigated pistachio shell powder (PSP), rich in antioxidants, as a functional feed ingredient for rainbow trout (Oncorhynchus mykiss). The effects of PSP inclusion (0%, 0.5%, 1%, 2%) on growth performance, intestinal health, and gut microbiota were assessed in fish fed either a fishmeal (FM) or plant meal (PM) diet over a 12-week feeding period. The results indicated that PSP inclusion at 1% significantly (p < 0.05) improved weight gain and growth performance in FM treatments, with no impact on growth in PM treatments. No significant differences were observed in other growth parameters, intestinal morphology, or oxidative stress markers, although a trend toward the downregulation of inflammatory genes was noted in PM treatments at 2% PSP inclusion. PSP inclusion did not significantly alter gut microbiota alpha diversity but affected beta diversity at the 0.5% level in the FM treatments (p < 0.05). Differential abundance analysis of gut microbiota revealed taxa-specific responses to PSP, particularly the genus Candidatus arthromitus, increasing in relative abundance with PSP inclusion in both the FM- and PM-based treatments. Overall, PSP inclusion up to 2% did not have significant adverse effects on the growth, intestinal health, or antioxidant status of rainbow trout.

Effects of dietary fish meal replacement by Periplaneta americana meal on growth, metabolism, intestinal health and resistance against Aeromonas hydrophila of Micropterus salmoides

An 8-week culture experiment was conducted to investigate the effects of partial replacement of fish meal (FM) with Periplaneta americana meal (PAM) on growth performance, body composition, serum biochemical parameters, intestinal health and resistance against Aeromonas hydrophila of largemouth bass, Micropterus salmoides. A total of 450 healthy largemouth bass with an initial body weight (IBW) of 14.55±0.09 g were randomly divided into five groups. Five experimental diets were prepared by replacing 0 % (P0), 15 % (P15), 30 % (P30), 45 % (P45) and 60 % (P60) of the FM in the basal diet with PAM, respectively. The results showed that final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) were no significant difference in P15 and P30 compared with the control group (P > 0.05). Crude protein of whole fish body was significantly increased and crude lipid was significantly decreased in all PAM groups (P < 0.05). In the P30, the antioxidant enzyme activities were significantly higher than those in the control and other experimental groups, and malondialdehyde (MDA) was significantly decreased (P < 0.05). The activities of α-amylase and pepsin increased significantly in P15 and P30 and decreased significantly in P45 and P60 (P < 0.05). Lipase was significantly increased in all groups except P15 than in the control group (P < 0.05). There were no significant differences in villus height (VH), crypt depth (CD), and muscle thickness (MT) among all groups (P > 0.05), but villus width (VW) was significantly decreased in P45 and P60 (P < 0.05). The relative expression of IL-10 and TGF-β1 were first up-regulated and then down-regulated, while IL-8 was opposite (P < 0.05). The relative expression of Casp3, Casp9 and IFN-γ were significantly up-regulated in P45 and P60 (P < 0.05). After injecting A. hydrophila, all groups of largemouth bass experienced mortality, but cumulative mortality was lowest in the P30. In conclusion, PAM can partially replace FM in the diet of juvenile largemouth bass. The replacement of no more than 30 % is unlikely to adversely affect growth performance, and can increase the crude protein content of the whole fish body, and is beneficial to intestinal health.

Effect of dietary glycerol monolaurate supplementation on gene expression, intestinal mucosa and microbiota of juvenile black sea bream (Acanthopagrus schlegelii).

Glycerol monolaurate (GML) is a chemical compound derived from the combination of lauric acid and glycerol, exhibiting potent antimicrobial properties. An eight-week feeding trial was conducted to evaluate the effects of dietary supplementation of Glycerol Monolaurate (GML) on juvenile black sea bream. The control diet included 24% fish meal, while five additional diets were formulated with increasing GML concentrations: 0.01% (GML1), 0.02% (GML2), 0.04% (GML3), 0.08% (GML4), and 0.16% (GML5). Each diet was assigned to triplicate tanks. At the end of the experiment, serum immune and antioxidant in liver were non-significantly different among the groups. The relative gene expression of IGF-1 and GH in liver was statistically higher in the GML3 treated. The relative gene expression of IL-1, TGF, TNF-1, CCK, CLDN1, CASS-3 and GPR41 in intestine were statistically higher in the GML3 group. The photomicrographs of transmission electron microscope of the intestine were also studied. The GML supplemented groups had longer brush borders. The cells seemed to be joined by an intact junctional complex without visible intercellular spaces. The observed variations in phyla, class, and genus did not demonstrate statistical significance. Proteobacteria, Cyanobacteria, Firmicutes and Actinobacteria in the phylum, and Oxyphotobacteria, Bacteroidia, Holophagae and Negativicutes in the class, Brevundimonas, and Achromobacter in the genera were all substantially increased with higher levels of GML supplementation. Based on these results, it is suggested that glycerol monolaurate (GML) may serve as a potential dietary supplement for promoting different gene expression and intestinal health in black sea bream.

The on growth, histology of intestinal and hepatopancreas of using black soldier fly (Hermetia illucens) larvae meal in the diets of Pontastacus leptodactylus juvenile

ABSTRACT In 60 days of feeding, a trial was conducted to evaluate the effects on liver, gut histology, and growth performance of using defatted black soldier fly Hermetia illucens (BSF) larvae meal as a fish meal (FM) protein alternative in the diet of Pontastacus leptodactylus. Fish meal protein was replaced with BSF meal protein at 0%, 20%, 40%, 60%, 80%, and 100%. Six hundred crayfish with an initial weight of 0.033 g were randomly divided into 24 experimental groups with four repetitions. There were no significant differences observed in cheliped, molting numbers, or survival rates between the groups (p > .05). However, adding more than 60% BSF to feeds caused pathological findings in the hepatopancreas,and the intestines. The results of this study showed that 40% defatted BSF meal can be used as a protein source replacement for fish meal protein without affecting the survival rate and growth of P. leptodactylus juveniles.

MrFeed Pro50 FF supplementation improves growth of Largemouth Bass fed a diet containing 160‐g/kg fish meal

AbstractObjectiveThis study aimed at evaluating the role of a novel commercial product, MrFeed Pro50 FF (MP50), as a functional ingredient with which to formulate low‐fish‐meal diets for Largemouth Bass Micropterus nigricans.MethodsSeven test diets were examined. A reference diet (RD) contained 400‐g/kg fish meal, and a control diet (C) was formulated by replacing 60% of the fish meal in RD with poultry by‐product meal. The other five diets were formulated by adding MP50 to C at 5.0 (D50), 7.5 (D75), 10.0 (D100), 12.5 (D125), or 15.0 (D150) g/kg. Fish (initial body weight = 9.2 ± 0.1 g) were fed the test diets for 8 weeks.ResultThe MP50 supplementation level significantly affected weight gain, final body weight, carbon retention efficiency, energy retention efficiency (ERE), hepatosomatic index (HSI), viscerosomatic index (VSI), the ratio of fish meal consumption to fish production (RCP), and carbon waste. The weight gain of fish fed D50, D75, and D100 was greater than that of fish fed C and D150. The ERE was greater in fish fed D50 and D100 than in fish fed C and D75. The HSI and VSI were greater and nitrogen and carbon wastes were lower for fish fed D50 and D100 than in fish fed C. Fish fed D50, D75, and D100 exhibited greater weight gain and lower RCP values compared with fish fed RD. The weight gain of fish fed RD did not significantly differ from the weight gain of fish fed C, D125, and D150, confirming that the minimum fish meal level could be reduced to 160 g/kg.ConclusionThis study indicates that MP50 at 5.0–10.0 g/kg can be used as a functional ingredient in low‐fish‐meal diets for Largemouth Bass.

Thraustochytrids and Algae as Sustainable Sources of Long-Chain Omega-3 Fatty Acids for Aquafeeds

There is limited ability to biosynthesize long-chain omega-3 fatty acids such as EPA and DHA in food webs leading to humans. Seafood is the key source of ω3 LC-PUFA, with aquaculture expected to meet rising global demand; however, marine fish have a high dietary requirement for EPA and DHA themselves. This was traditionally met using unsustainable dietary fish oil and fish meal, but limited supply and environmental concerns have dictated research on replacements. Among the industrial sources of EPA and DHA, microalgae and especially thraustochytrids stand out as resources with high concentrations. Although unicellular, thraustochytrids are not microalgae as they are not photosynthetic but instead are microheterotrophs. This removes the light requirement and facilitates high yields of monoculture for the production of single-cell oils. The availability, in high concentrations, of usually one or the other essential fatty acid permits a calibration of the EPA and DHA dose, which is especially useful as their effects have mainly been considered together in medical and aquaculture research. EPA and DHA have different effects on cell function and are precursors of different bioactive compounds. Using thraustochytrids, microalgae, and heterotrophic dinoflagellates, the importance of DHA has been investigated. DHA was essential for optimizing the growth of the early life stages of scallops and finfish and was preferentially incorporated into fish membrane phospholipids. The production of microalgae and microheterotrophs can contribute to the treatment of wastewater and waste gas, further enhancing their sustainability and reducing the environmental costs of aquaculture.

Dietary administration of Bacillus amyloliquefaciens AV5 on antioxidant activity, blood parameters, and stress responses of Nile tilapia (Oreochromis niloticus) raised under hypoxia and temperature variability

The ability of Nile tilapia to tolerate hypoxia, as well as low and high temperatures, presents a significant economic concern, as it adversely affects their growth and leads to increased mortality rates. A 42-day feeding trial was conducted to evaluate the impact of adding Bacillus amyloliquefaciens AV5 to a fish meal on the physiological response of Nile tilapia. Three meals were administered to fish (23.4 ± 0.3g) in triplicates. The diets included GC (without B. amyloliquefaciens AV5), G1 (106 cfu/g), and G2 (108 cfu/g). After the treatment trial, we assessed the antioxidant parameters, hemato-immunological indices, and stress-related genes in O. niloticus. Subsequently, we subjected the fish to hypoxia for 20h and low and high temperatures for 3h each. The findings demonstrated a significant rise in white blood cells, red blood cells, haemoglobin, and hematocrit levels in the blood of fish that were fed a meal supplemented with B. amyloliquefaciens AV5, compared to the control group (GC) (P<0.05), the serum of all fish groups that were supplemented with B. amyloliquefaciens AV5 exhibited an increase in catalase, total antioxidant capacity and superoxide dismutase activity and a decrease in lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, pyruvate kinase, myeloperoxidase, glucose, cortisol (P < 0.05). In addition, all fish diet groups that received B. amyloliquefaciens AV5 as a supplement exhibited elevated levels of HIF-1α and HSP70 expression in their livers (P<0.05). Nile tilapia in the G2 diet, exhibited improved values in most evaluated indices under various stress settings (P<0.05). These data indicate that the G2 supplement may be used as a preventive measure to weaken the impacts of environmental stress on O. niloticus.

Review on Silk Worm Pupal Meal: A Protein Source in Aquatic Animal Nutrition as a Replacement of Fish Meal

Amongst the insect meals, silkworm pupal meal is the most efficient fish meal replacement. It can be utilized in aquatic animal feeds as pupal meal, deoiled silkworm pupal meal and fermented pupal meal, to increase growth performance. It also has a significant impact on animal body composition and digestive enzyme activity. India is the world's second-largest producer of silk, and a vast amount of silkworm pupae waste is discharged into the environment, which can be used as protein in feed. It has a strong nutritional profile that is near or equal to fish meal, consists of 50-80% of crude protein on dry matter, rich in important amino acid profile, (methionine 3.5, lysine 7.0, aspartic acid 10.4, threonine 5.2, serine 5.0, glutamic acid 13.9, proline 5.2, glycine 4.8, alanine 5.8, cystine 1.0, valine 5.5, isoleucine 5.1, leucine 7.5, tyrosine 5.9, phenylalanine 5.1, histidine 2.6, and arginine 5.6) and lipid content ranges from 20-40% in freshly spent pupa and less than 10% in defatted pupa. The oil derived from pupa is high in alpha-linolenic acid, oleic acid, palmitic acid and the gross energy values range from 5.09 to 6.28 MJ/kg. It also contains interesting minerals and vitamins, which piqued the interest of researchers in its use in aqua feed. Aside from the nutritional profile, nutrient digestibility, and the effect of diet on organoleptic quality revealed that SWP meal is equivalent to fish meal in all respects. So, the current review focuses on the effects of silkworm pupal meal on aquatic animals when supplied through diets.

Effects of Substituting Fishmeal with Soy Protein Concentrate Supplemented with Essential Amino Acids in the Olive Flounder (Paralichthys olivaceus) Diet on the Expression of Genes Related to Growth, Stress, Immunity, and Digestive Enzyme.

This study identified the effects of substituting fishmeal (FM) with soy protein concentrate (SPC) supplemented with lysine and methionine in the olive flounder (Paralichthys olivaceus) diet on the expression of genes related to growth, stress, immunity, and digestion. Three experimental diets were prepared; the control diet (Con) contained 60% FM, and the experimental diets contained 25% (SPC25) and 50% (SPC50) FM replaced by SPC. After the 140-day feeding period, weight gain, specific growth rate, feed availability, biological indices, and chemical composition of the muscle were not significantly affected by the dietary treatments. The gene expression levels of growth-related genes (IGF, GFB-3), immune-related genes (IL-8 and caspase), and stress-related genes (SOD, GPX, PRX, TRX) were higher in Con fish than in those fed the SPC25 and SPC50 diets. Chymo-TRY2, TRY2, and TRY3 in the stomach of fish fed the SPC25 diet were higher than fish fed the Con or SPC50 diets. TRY2 and lipase of fish fed the SPC25 diet were higher than those of fish fed the other diets but TRY3 was not significantly affected by the treatments in the intestine. In conclusion, substituting 25% FM with SPC was the most effective diet for the expression of growth, immune, stress, and digestive enzyme genes.

Hydroxyprolyl-Glycine in 24 H Urine Shows Higher Correlation with Meat Consumption than Prolyl-Hydroxyproline, a Major Collagen Peptide in Urine and Blood.

Background. Urinary collagen peptides, the breakdown products of endogenous collagen, have been used as biomarkers for various diseases. These non-invasive biomarkers are easily measured via mass spectrometry, aiding in diagnostics and therapy effectiveness. Objectives. The objective of this study was to investigate the effects of consuming collagen-containing meat on collagen peptide composition in human blood and urine. Methods. Ten collagen peptides in 24 h urine were quantified. Results. Prolyl-hydroxyproline (Pro-Hyp) was the most abundant peptide. Except for hydroxyprolyl-glycine (Hyp-Gly), levels of other minor collagen peptides showed high correlation coefficients with Pro-Hyp (r = 0.42 vs. r > 0.8). Notably, 24 h urinary Hyp-Gly showed a correlation coefficient of r = 0.72 with meat consumption, significantly higher than the coefficient for Pro-Hyp (r = 0.37). Additionally, the levels of Pro-Hyp and Hyp-Gly in the blood of seven young women participants increased similarly after consuming fish meat, while before ingestion, only negligible amounts of Hyp-Gly were present. To examine which peptides are generated by the degradation of endogenous collagen, mouse skin was cultured. The amount of Pro-Hyp released from the skin was approximately 1000-fold higher than that of Hyp-Gly. Following consumption of collagen-containing meat, both Pro-Hyp and Hyp-Gly are released in blood and excreted into urine, although Pro-Hyp is primarily generated from endogenous collagen even under physiological conditions. Conclusions. Therefore, in 24 h urine samples, the non-negligible fraction of Pro-Hyp is contributed by endogenous collagen, making 24 h urine Hyp-Gly level a potential biomarker for evaluating meat consumption on the day.

Exploring Fish Parvalbumins through Allergen Names and Gene Identities

Parvalbumins are the main source of food allergies in fish meat, with each fish possessing multiple different parvalbumins. The naming convention of these allergens in terms of allergen codes (numbers) is species-specific. Allergen codes for parvalbumin isoallergens and allergen variants are based on sequence identities relative to the first parvalbumin allergen discovered in that particular species. This means that parvalbumins with similar allergen codes, such as catfish Pan h 1.0201 and redfish Seb m 1.0201, are not necessarily the most similar proteins, or encoded by the same gene. Here, we aim to elucidate the molecular basis of parvalbumins. We explain the complicated genetics of fish parvalbumins in an accessible manner for fish allergen researchers. Teleost or modern bony fish, which include most commercial fish species, have varying numbers of up to 22 parvalbumin genes. All have derived from ten parvalbumin genes in their common ancestor. We have named these ten genes “parvalbumin 1-to-10” (PVALB1-to-PVALB10), building on earlier nomenclature established for zebrafish. For duplicated genes, we use variant names such as, for example, “PVALB2A and PVALB2B”. As illustrative examples of our gene identification system, we systematically analyze all parvalbumin genes in two common allergy-inducing species in Japan: red seabream (Pagrus major) and chum salmon (Oncorhynchus keta). We also provide gene identifications for known parvalbumin allergens in various fish species.

Evaluation of storage stability of poultry by-product meal incorporated fish feed under aerobic storage condition

The research focused on development of fish feed utilising poultry by-product meal (PBM) as a substitute for fish meal (FM) and evaluating its shelf life under aerobic packaging conditions. Initially, a basal diet (C) was formulated to meet the nutritional requirements for optimal growth of Tilapia by using FM as the major protein source. After analysing the nutritional composition of PBM, an isoproteinaceous diet (T) was formulated by replacing FM with PBM. The product was packed in HDPE bags and kept at room temperature and analysed for physico chemical and microbial characteristics for 45 days at weekly intervals. Moisture content of both C and T decreased significantly (p0.05) was found between C and T. The TBARS value of both C and T followed an increasing trend. This increase in C was not significant (p&lt;0.01) between 28th and 35th day, and between 42nd and 45th day but that of T increased significantly (p&lt;0.01) throughout the storage period. T consistently displayed the highest TBARS value during storage period. Tyrosine Value (TV) of both C and T also increased during storage and was significant (p&lt;0.01) up to 42nd day of storage. C exhibited the highest TV throughout the storage period. Similarly, total viable count (TVC) of both C and T increased on storage. The increase in TVC for C was not significant (p&lt;0.01) between 21st and 28th days, whereas that of T was significant (p&lt;0.01) throughout the storage period. On 45th day, T exhibited highest count and was significantly different (p&lt;0.01) from C. Throughout the 45-day storage period, no observable coliform count or yeast and mould count was noted in either C or T. The present study indicated that fish feed can be effectively prepared by utilising PBM and can be stored under room temperature up to 45 days. Keywords: Poultry by-product meal, fish meal, fish feed, storage stability

Natural Feed Supplements From Crustacean Processing Side Streams for Improved Growth of Finfishes and Crustaceans: A Review.

Natural feed additives of plant/animal/microbial origin are researched as supplements in aquaculture to improve the properties of feed, minimize the usage of chemical alternatives, reduce food safety risks and ensure sustainability to combat global food and nutritional security. Side streams generated during shellfish processing possess valuable ingredients: protein, lipids, carotenoids, minerals and chitins. Considering the current trend of organic farming and antibiotic-free fish and shellfish, crustacean processing side streams and their derivatives seem promising and emerging resources as natural additives/supplements for formulating high-quality feeds with superior benefits. Lower concentrations of chitin and chitosan in diets are reported to stimulate the growth of shellfish and finfish under controlled conditions. Oligomers of chitosan and nano-chitosan are also the other potential derivatives as natural supplements in feed for better growth performance of aquaculture varieties. This review focuses on the significance of crustacean processing side streams and their derivatives, especially shrimp head meal, chitin, chitosan and chitosan oligosaccharides as potential natural additives in aquafeeds for promoting the growth performance of cultured fin fishes and shell fishes. Utilization in aquafeeds and the development of natural value-added supplements from crustacean processing side streams, especially shrimp head and shell leftover, offer an answer to the negative environmental impact due to its dumping; reduce the dependency on food fish for fish meal production & fishmeal for aquafeeds; solution to maintain the economic viability of the fish farmers & industry as well as to ensure the supply of safer and healthy aquatic foods to meet the objectives of sustainable development goals.

Biological invasions into planktonic and bottom communities of the Kaliningrad (Vistula) Lagoon of the Baltic Sea and their impact on the food supply and fish catches

Biological invasions into planktonic and bottom communities of the Kaliningrad (Vistula) Lagoon of the Baltic Sea and their impact on the food supply and fish catches

Effect of Dietary Supplementation of Glycerol Monolaurate on Growth Performance, Digestive Enzymes, Serum Immune and Antioxidant Parameters, and Intestinal Morphology in Black Sea Bream.

An eight-week feeding trial was conducted to examine the impact of dietary supplementation with glycerol monolaurate (GML) on juvenile black sea bream. A basal diet was formulated containing 24% fish meal, while five additional diets were prepared, each supplemented with varying levels of GML: GML1 (0.01%), GML2 (0.02%), GML3 (0.04%), GML4 (0.08%), and GML5 (0.16%). Triplicate tanks were randomly allocated to each diet, each containing 20 fish with an initial weight of 1.55 ± 0.05 g. By the trial's end, the GML3 group displayed a notably higher final body weight (FBW), weight gain (WG), specific growth rate (SGR), and protein efficiency ratio (PER) compared to the other groups (p < 0.05), but the FCR was significantly higher in the control group. However, no significant differences were observed in the MFI, PPV, CF, HSI, IPF, VSI, or SR among the groups (p > 0.05). Regarding the proximate compositions of the dorsal muscle and whole body, no substantial differences were observed across the groups (p > 0.05). Additionally, there were no significant variations in digestive enzyme activity (p > 0.05), serum immune, or biochemical parameters in the midgut and hindgut among the treatment groups. But in the serum immune response IgM, C3 and C4 were significantly higher in the GML3 group as compared to the other groups (p < 0.05). However, the GML3 group exhibited significantly greater fore-intestinal villus height, crypt depth, villus height per crypt depth, and the number of goblet cells per villus compared to the other groups (p < 0.05). Overall, GML supplementation, particularly GML3, significantly improved growth indicators like the final body weight and intestinal morphology. While certain parameters remained unaffected, these findings suggest GML's potential as a beneficial dietary supplement in fish diets.

High soybean dietary supplementation with quercetin improves antioxidant capacity of spotted sea bass Lateolabrax maculatus

This study aimed to examine the effect of quercetin (QUE) on the antioxidant capacity of spotted sea bass that were fed a high soybean meal diet. 44 % fish meal was used as a healthy control, and soybean meal instead of 50 % fish meal induced a negative reaction. On this basis, 0.25, 0.50, 0.75, and 1.00 g/kg QUE were added, respectively. A total of 540 spotted sea bass were randomly allocated into 6 groups and provided with diets that corresponded to their respective groups for a duration of 56 days. The results showed a significant decrease in the antioxidant capacity of spotted sea bass fed a high soybean meal diet. The inclusion of QUE considerably improved the antioxidant capacity of spotted sea bass. This was evidenced by the notable rise in glutathione (GSH) levels in the intestine and liver, as well as the elevated levels of catalase (CAT) and total antioxidant capacity (T-AOC) in the liver. Furthermore, transcriptome results showed that the S-transferase (GST) gene in the glutathione metabolism pathway was significantly down-regulated by high soybean meal, while with the addition of QUE, noteworthy alterations in genes associated with the PI3K-Akt signaling pathway, Foxo signaling pathway, and AMPK signaling pathway. These signaling pathways are involved in signal transduction, apoptosis, and oxidative stress. On the other hand, genes related to energy metabolism, such as phosphoenolpyruvate carboxykinase (PEPCK), were observed to be upregulated. These pathways could potentially contribute to the antioxidant properties of QUE.

Pervasive Microplastic Ingestion by Commercial Fish Species from a Natural Lagoon Environment

Microplastics have emerged as a significant global environmental concern in the recent decade. The aim of this study was to elucidate microplastic contamination of commercial fish species in a natural lagoon environment. Microplastic contamination was examined in the gastrointestinal tracts and gills of 157 commercial fish from 18 species with varying feeding habits in a vital and sensitive lagoon ecosystem, which connects to the Indian ocean. Microplastics were extracted using digestion, followed by stereomicroscopic inspection using Nile Red stain, and identified via μ-FTIR analysis. Over half of studied fishes ingested microplastics (54.14%). Filaments (50%) and blue items (43%) were the most commonly ingested. Of all the fish species, Eubleekeria splendens had the highest average concentration of microplastics in GIT (1.41 ± 2.52 items/g w.w. tissues), although no statistically significant difference in amount of ingested microplastics (items/g w.w. tissues) was observed among species. The highest concentrations of inhaled microplastics were recorded in Sillago vincenti (1.38 ± 1.30 items/g w.w. tissues). The majority of the extracted microplastics (33%) belonged in the size class 500–1500 μm with rayon, polyethylene terephthalate, and polypropylene as the primary polymers. This study found no correlation between microplastic ingestion and fish species and feeding habits, but a positive correlation with fish size was observed. These findings reveal widespread microplastic contamination in edible fish, posing potential risks to commercially important species due to increasing pollution in lagoon ecosystems.

Determination of the protein value of novel poultry meal ingredients for rainbow trout, Oncorhynchus mykiss

AbstractThe aim of this study was to assess the digestible protein value of three novel poultry products (Pea/Lentil‐PM, Hen on Hen‐PM, and soybean meal (SBM)‐PM), then a growth trial with a 2 × 5 design was conducted where SBM‐PM was included at five levels: 0, 5, 10, 15, and 30% in both a fish meal (FM)‐based diet and a plant protein (PP)‐based diet. Thirty rainbow trout (initial size = 10.7 ± 0.15 g; Troutlodge Inc, Sumner, WA) per tank were stocked into a 15°C recirculating system. Fish in triplicate tanks were fed twice daily to apparent satiation for 12 weeks. SBM‐PM had no effect on final weight (p = 0.3665; FM 233 vs. PP 237) or growth rate (p = 0.4703; FM 2070% vs. PP 2097%). Significant interactions between dietary protein and SBM‐PM for both intake (p = 0.0080) and FCR (p = 0.0081) indicate increased intake of fish fed the plant protein‐based diet without SBM‐PM. Regression modeling of this effect yields a polynomial model with an R‐square of 0.78; p &lt; 0.0001 explained by the relationships: and , respectively. These values suggest that the SBM‐PM can be included up to 30% in rainbow trout feeds to reduce feed costs without negatively impacting performance.

Replacement of fish meal with defatted black soldier fly (Hermetia illucens) in diet of Pacific white shrimp (Litopenaeus vannamei): growth, flesh quality and transcriptome

Abstract This study evaluated the impacts of replacing fish meal (FM) with defatted black soldier fly (Hermetia illucens; BSF) on the growth performance, flesh quality and transcriptome of Pacific white shrimp (Litopenaeus vannamei). In a diet containing 560 g/kg FM, BSF was used to replace 0%, 20%, 40%, 60%, 80% and 100% of dietary FM (BSF0, BSF20, BSF40, BSF60, BSF80 and BSF100). Thus, six isonitrogenous and isolipidic diets were prepared, and then fed to juvenile Pacific white shrimp (1.70 ± 0.10 g) for 60 days. In growth performance, the BSF20 group showed the similar FCR and WGR to the control group (), and the other four BSF groups presented significantly lower WGR and higher FCR than the BSF0 group (). The flesh chewiness and the contents of crude lipid, collagen and total amino acid in flesh were significantly decreased (), and flesh cooking loss, thawing loss was significantly increased when the replaced FM was ≥40% (). When the replaced FM reached 60%, the flesh hardness, heat-insoluble collagen content, shear force, body surface redness and the ratio of n-3/n-6 fatty acids were significantly lower (), while n-6 polyunsaturated fatty acid content and total free amino acid content in flesh were significantly higher than those of the BSF0 group (). Hepopancreatic samples were used for transcriptomic analysis, and a total of 1,456 differentially expressed genes (DEGs) were identified between the BSF groups and BSF0 group, which were mainly involved in growth-promoting, energy metabolism and antioxidant capacity key pathways and genes, including the cathepsin L, folate synthesis pathway, redox-related genes and glutathione metabolism pathway. In conclusion, in a diet containing 560 g/kg FM, BSF could successfully replace 20% of dietary FM, and higher FM replacement (≥40%) decreased the growth performance and flesh quality of Pacific white shrimp.