Aquaculture Nutrition最新文献

The aquafeed industry relies on fish meal as a major protein source, but its use raises economic and environmental concerns, prompting the search for sustainable alternatives. This study compared the apparent digestibility coefficients (ADCs) of dry matter (DM), energy, protein, phosphorus, lipids, and amino acids (AAs) for selected protein ingredients in Coho salmon. For this purpose, one reference and seven test diets corresponding to beer yeast (BY), corn gluten meal (CGM), cottonseed meal (CSM), peanut meal (PNM), rapeseed meal (RSM), soybean meal(SBM), and soy protein concentrate (SPC) were formulated with the ratio of 70:30 of the reference diet and one of the test ingredients. 1200 fish were randomly distributed into 24 glass aquaria (each with a diameter of 3.0 m and a depth of 1.5 m, water volume 8.5 m³) with three aquaria per experimental diet (total n = 50 ^∗24 = 1200). The experiment lasted for 8 weeks. The results indicated that ADCs of DM ranged from 43.34% for RSM to 72.90% for SPC. Similarly, the highest ADCs of crude protein (72.69% to 86.76%), lipid (77.09% to 87.72%), and gross energy (74.12% to 55.44%) were observed in SPC, and the lowest were found in RSM. However, the ADCs of phosphorus ranged from 36.14% (RSM) to 47.35% (SBM). The ADCs of proximate nutrients for BY, CGM, PNM, SBM, and SPC were significantly higher (p  < 0.05) than other protein ingredients (RSM, CGM). Similar patterns of digestibility were observed for individual AAs of the test ingredients. Overall, the diet containing SPC appeared to be more suitable and compatible with the reference diet. Conversely, PNM, BY, SBM, and CGM showed some potential as aquafeed ingredients, whereas CSM and RSM appear to be the least viable options. Such information aids in better feed formulation by focusing on nutrient absorption rather than raw ingredient composition.

Feeding marine larvae commonly relies on live prey, which must be enriched with lipid emulsions and/or microalgae rich in long-chain polyunsaturated fatty acids (LC-PUFA) before being added to larval tanks. This enrichment enhances the nutritional value of live feed and supports larval health and growth. Microalgae are also used in aquaculture as a primary feed source for larvae and for maintaining water quality. However, in-house microalgal cultures are costly, prone to contamination, and require complex harvesting. Sourcing live microalgae from external specialized facilities is also expensive and complicated, as it involves transporting highly diluted biomass, creating a major bottleneck in hatcheries. Consequently, alternative formats of microalgal biomass, including fresh or dried forms, are gaining attention for their ease of use, nutritional stability, and antioxidant potential. To evaluate some of these concentrated biomass substitutes, different formats of Isochrysis galbana (spray-dried [ISD], fresh [IFRE], and frozen [IFRO]) were tested on the rotifer Brachionus plicatilis and Artemia. Prior to the assay, the total antioxidant capacity and lipid composition of the microalgal products were evaluated. Subsequently, live prey were fed the different I. galbana formats for 24 h, after which prey survival, lipid composition, and oxidative status were assessed. Our results showed that fresh/frozen I. galbana exhibited the highest in vitro antioxidant activity, particularly in the ethyl acetate fraction. However, rotifer survival was compromised when using the IFRE format. The spray-dried microalgae was the best format to enhance phospholipid retention in both zooplankton species, also increasing DHA/EPA (22:6n–3/20:5n–3) ratio and n–3 LC-PUFA content in rotifers. ISD also reduced lipid peroxidation in Artemia without negatively affecting the live prey culture. In conclusion, based on lipid composition and antioxidant potential, ISD was the most effective format for feeding rotifers and Artemia.

The study of flow and transformation of energy and nutrients via mathematical modelling provides an in silico tool approach for designing scientific experiments, improving precision in aquaculture production and reducing the need for experimental animals. The proposed nutritional bioenergetics model is based on the dynamic energy budget (DEB) theory, a mechanistic framework to study individual metabolism. The model is an extension of the typical DEB models in that it includes a digestion module where the protein and non-protein food components contribute to assimilation via the concept of a synthesising unit (SU). The model allows predictions for measurable quantities of interest for aquaculture, including feeding rate, oxygen consumption, carbon dioxide, ammonia and solid waste production, under various temperatures and feeding conditions, both in terms of quantity and macronutrient composition. The feeding schedule’s effects, such as the diurnal variation in waste production in response to feeding frequency, are also captured. The model quantifies the effects of the dietary protein-to-energy ratio on food intake and assimilation; energy-rich diets or those with excessive or poor amounts of protein show reduced intake. The model has been parametrised and validated for rainbow trout (Oncorhynchus mykiss) to demonstrate its capabilities. Testing the model with diverse datasets has shown that it predicts weight gain well, and to a lesser extent, oxygen consumption and total ammonia production. The proposed model could be a useful in silico tool for fish researchers, technicians and farm operators.

This study examined the growth performance, cellular signaling, and gut microbiome of gilthead sea bream (Sparus aurata) fed four diets using low-trophic-level ingredients for 65 days. Control (C) diet contained fish meal (FM) as the main protein source and fish oil (FO) as a lipid source. In the 0%FMFO diet all FM and FO present in the C diet was replaced with a combination of microalgae, insect meal (IM), and tunicate meal (TM). IM and TM diets were formulated to contain 20% of the novel protein ingredients, replacing 68.09% and 45.91% of FM in diet C, respectively. Compared to diet C, feed utilization and growth performance of S. aurata fed 0%FMFO diet was not different (p > 0.05) and TM diet had a significantly lower (p  < 0.05) specific growth rate (SGR), higher (p  < 0.05) feed conversion ratio (FCR) and decreased fillet lipid content (p < 0.05). In liver and foregut of fish fed TM diet the activity of lactate dehydrogenase (L-LDH) significant increased (p < 0.05), indicating higher glycolytic potential, whereas the decrease in Hsp70, Hsp90, AMPK, and p38 MAPK may indicate reduced stress response. Fish midgut microbiome included beneficial taxa for the host. The results suggested that the mixture of algae, insect, and TM could replace all FM and FO in gilthead sea bream diets without affecting the fish growth performance.

With the rising incorporation of alternative protein sources in fish diets, understanding amino acid (AA) supplementation strategies, including glycine, optimizes fish growth performance and immune function. A 12-week feeding trial evaluated the effect of dietary glycine (Gly) supplementation on the growth performance and blood biochemistry of juvenile Florida pompano (Trachinotus carolinus; 19.55 ± 0.32 g). Experimental diets incorporated soybean meal (SBM), poultry by-product meal (PBM), and corn protein concentrate, and were formulated to contain 40% crude protein and 8% crude lipid. Glycine was supplemented at 0%, 0.25%, 0.5%, and 1%, with alanine (Ala) adjustments to ensure all diets were isonitrogenous. Growth metrics, including final weight (FW) (85.21–90.93 g), weight gain (WG) (336%–366%), and feed conversion ratio (FCR) (1.61–1.69), showed no significant differences among treatments. A significant linear decrease in the hepatosomatic index (R² = 0.244, p = 0.027), stable liver enzymes, and a significant increase in serum cholesterol at 1% glycine supplementation (R² = 0.507; p = 0.002) suggest that glycine may influence hepatic metabolism, potentially through enhanced bile acid conjugation. Whole-body proximate composition and AA profiles remained unchanged, and serum lysozyme activity (SLA) showed no significant variation across treatments (p = 0.730). These findings suggest that glycine supplementation did not enhance growth but influenced some metabolic parameters. Further research is suggested to clarify the underlying mechanisms under various cultural conditions and stress challenges.

Understanding the molecular underpinnings of feed efficiency (FE) is crucial for advancing sustainable aquaculture, particularly under fishmeal-free (FM-free) dietary strategies. This study investigated the physiological, transcriptomic, and metabolomic differences between high-FE and low-FE Larimichthys crocea individuals fed a plant-based diet. High-FE fish exhibited significantly higher activities of hepatic amylase (AMS), hepatic lipase (HL), and lipoprotein lipase (LPL), as well as changed serum albumin (ALB) and peroxidase (POD) levels, suggesting enhanced digestive function and antioxidant capacity. Transcriptomic analysis revealed 239 differentially expressed genes (DEGs), with significant enrichment in steroid biosynthesis, ribosome biogenesis, and autophagy pathways. Genes involved in glycolysis were downregulated, indicating a metabolic shift toward increased reliance on lipid and protein catabolism. Metabolomic profiling identified 359 differentially expressed metabolites (DEMs), primarily comprising lipids and amino acids, enriched in pathways related to amino acid metabolism, energy production, and ABC transporter activity. Integrative O2PLS and correlation analyses identified tightly linked gene–metabolite pairs, such as pfkp and peptide fragment, and highlighted mao as a regulatory factor that links energy and protein digestion. Protein–protein interaction (PPI) analysis identified five hub genes (tpi1, tktl2, fdps, pgam1, and ldha) that are central to metabolic coordination. These findings offer comprehensive insights into the metabolic reprograming and regulatory mechanisms underlying enhanced FE in L. crocea, highlighting potential molecular targets for selective breeding and feed optimization in FM-free aquaculture systems.

Herbal bioactive compounds are effective in enhancing the antioxidant and immune status of fish, as they effectively neutralize oxidative stress. The present study examined the effectiveness of Ivy (Hedera helix) leaf extract (ILE) on growth performance, immune responses, antioxidant parameters, and the expression of immune-related genes in rainbow trout (Oncorhynchus mykiss). Four test diets were prepared as follows: a control diet at 0 mg of ILE (ILE0) and diets of 100 mg (ILE100), 150 mg (ILE150), and 200 mg (ILE200) of ILE/kg. A total number of 240 rainbow trout, with an initial weight of 6.38 ± 0.30 g, were divided into 12 tanks and fed on the experimental diets for 8 weeks. Results indicated that ILE150 and ILE200 exhibited significantly higher final weight (FW), weight gain, and specific growth rate compared to the control and ILE100 treatments. Additionally, fish fed with ILE showed significantly higher activity of digestive enzymes, including trypsin, pepsin, proteases, lipase, and amylase compared to the control group. The experimental diets also significantly affected hematological indices, including erythrocytes, leukocytes, hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration, and mean corpuscular hemoglobin, and their highest levels were observed in ILE150 and ILE200. Furthermore, a notable reduction was observed in aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) activities in all ILE-supplemented diets. Serum antioxidant enzymes, including catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD), significantly increased in ILE150 and ILE200, but serum malondialdehyde (MDA) levels significantly declined in treatments fed with ILE compared to the control group. Alternative complement, total immunoglobulin, total protein, and lysozyme levels were significantly higher in ILE-supplemented-diet treatments. The results also showed a significant upregulation of immune-related genes, such as interleukin 1β, interleukin-6, interleukin-8, and lysozyme, in ILE150 and ILE200 compared to the control and ILE100. In conclusion, administering ILE at doses of 150–200 mg/kg diet could improve the growth performance and immune-antioxidant capacity of rainbow trout.

In this study, the freshwater microalga Coelastrella terrestris NIOF17/005 was utilized as a feed additive for the Pacific whiteleg shrimp (Litopenaeus vannamei). Coelastrella terrestris was characterized morphologically, phylogenetically (using 18s rRNA), and biochemically. Shrimp diets were supplemented with C. terrestris at 0, 1, 2.5, and 5 g/kg. After a 56-day feeding trial, the biochemical analysis of C. terrestris revealed a composition of 38.12% protein, 37.82% lipids, and 15.75% carbohydrates, with valuable bioactive compounds including polyunsaturated fatty acids and antioxidant substrates. The supplementation of 2.5 g/kg C. terrestris significantly improved the growth performance of L. vannamei (10.23 g final weight), survival rate (92.67%), and feed conversion ratio (1.71). The whole-body composition analysis of L. vannamei indicated enhanced protein content (59.74%) and lipid content (7.92%) in the algal-supplemented groups in comparison to the control. Digestive enzyme activities of amylase and lipase increased significantly, with peak activities observed at 2.5 g/kg supplementation (49.55 and 60.06 IU/L, respectively). Nonspecific immunity parameters, including lysozyme (4.47 µg/mL), superoxide dismutase (SOD; 10.77 IU/g), and catalase (CAT; 10.47 IU/g) activities, were substantially elevated in shrimp-fed C. terrestris-supplemented diets, with optimal levels at 2.5 g/kg. The gene expression analysis showed that both studied growth-related genes and immunity-related genes were upregulated. These genes reached their maximum expression at a supplementation level of 2.5 g/kg, with the expression levels being approximately 2–3 times higher in the supplemented group in comparison to the control group. In conclusion, these findings suggested that the inclusion of C. terrestris NIOF17/005 (2.5 g/kg) into shrimp feed formulations could enhance productivity, improve shrimp health, and potentially increase the sustainability of shrimp farming operations.

Macroalgae have long been utilized as a natural feed source in abalone aquaculture. The switch to formulated feeds improves nutritional control while reducing the cost instability of natural feeds. Recently, lipid supplementation has received a lot of attention since it is essential to the early developmental and broodstock stages of aquatic species. The present study aimed to investigate how the growth and reproductive performances of female broodstock Haliotis discus hannai were affected by the dietary supplementation of five lipids: fish oil (FO), perilla seed oil (PO), safflower oil (SO), olive oil (OO), and lard (LO). A total of 500 adult female abalones were randomly divided into five groups (four replicates per group) and fed with five lipid-supplemented diets for 90 days. The LO group was the worst (p < 0.05), while the FO group significantly showed the best growth performance, gonad index (GI), fertility, fertilization rate, larvae hatching rate, and larval attachment rate (p < 0.05). Meanwhile, the FO and PO groups exhibited significantly higher levels of very low-density lipoprotein (VLDL), vitellogenin (VTG), gonadotropin-releasing hormone (GnRH), progesterone (PROG), and 17β-estradiol (E₂) than the LO group (p < 0.05), indicating their higher ovarian developmental maturity. Furthermore, histological and fatty acid analysis revealed that the FO group contained high levels of polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which may contribute to ovarian maturation and egg quality. Therefore, the best lipids for improving the growth and reproductive performances of female abalone might be FO enriched in highly unsaturated fatty acids rather than plant-derived lipids, providing new insights into nutritional research and applications in vegetarian mollusks.

Pomelo peel is a main by-product of pomelo consumption, while most of the by-products are discarded as wastes with environmental threats. Indeed, it contains many nutrients and bioactive ingredients, which makes it a promising source of aquatic feedstuff. In this study, a 56-day feeding trial was set out to assess the dietary application of pomelo peel and soybean meal (SBM) (1:4 ratio) fermented compound (PSFC) in large yellow croaker (Larimichthys crocea). Results indicated that dietary PSFC improved weight gain rate (WGR) and specific growth rate (SGR), but did not affect feed utilization, body shape parameters and survival rate (SR) of croakers. Moreover, PSFC significantly decreased serum diamine oxidase (DAO) activity and D-lactate concentration, increased muscle thickness and villus height, as well as upregulated occludin, claudin-11, ZO-1 and JAM mRNA levels. The inhibition of proinflammatory IL-1β and promotion of anti-inflammatory IL-4/13b and IL-10 expressions were documented in croakers fed with PSFC. Dietary PSFC upregulated intestinal TLR1, TLR2A, and TLR2B expression, which had significantly positive correlations with improved inflammatory status. Furthermore, PSFC application caused clear alterations in the intestinal microbiota of croakers, which characterized with decreased relative abundances of Verrucomicrobiota and Acidobacteriota and increased relative abundances of unclassified_Muribaculaceae and Akkermansia. Overall, PSFC can significantly improve growth and intestinal health of L. crocea, and showed potential as protein source on L. crocea culture. This work offers a novel insight into the development of fermented protein sources for aquafeeds using pomelo peel and SBM as fermentation ingredients.