Aquaculture Nutrition最新文献

The present study determined the apparent digestibility coefficients (ADCs) of dry matter, nutrients, and energy in selected seven animal protein ingredients, including Peruvian fish meal (PFM), native fish meal (NFM), Antarctic krill meal (AKM), native shrimp meal (NSM), poultry by-product meal (PBPM), meat and bone meal (MBM), and hydrolyzed feather meal (HFM) for coho salmon (Oncorhynchus kisutch) post-smolts (initial body weight: 212.73 ± 5.15 g). Using yttrium oxide (Y₂O₃, 0.5 g/kg) as an inert marker, a reference diet was formulated to contain ~440 g/kg of crude protein and 200 g/kg of crude lipid, whereas the test diets were composed of the reference diet and one of the test ingredients at a ratio of 70:30. The dry matter ADCs of the test animal protein ingredients ranged from 65.14% to 83.77%. The ADC of energy followed a similar trend to that of dry matter (69.03%–87.52%). The crude protein and lipid in all the test ingredients were well digested by the post-smolts with ADCs ranging from 74.12% to 91.67% and 75.44% to 92.38%, respectively. The MBM and HFM had significantly (p < 0.05) lower amino acid ADCs than other animal protein ingredients, resulting in lower levels of protein digestion in these two terrestrial animal ingredients. The ADCs of phosphorus varied greatly among the animal protein ingredients, with the highest in PBPM (70.52%) and the significantly (p < 0.05) lowest in MBM (37.31%). These ADCs data suggest that PFM, NFM, AKM, NSM, and PBPM can be prioritized as high-quality protein sources and provide more accurate information for the nutrient and energy utilization of coho salmon.

This study evaluated the digestibility of defatted black soldier fly larvae (BSFL, Hermetia illucens) meals as alternative protein sources to partially replace fish meal (FM) in blue shrimp (Penaeus stylirostris) diets. It also examined the relationship between in vivo and in vitro digestibility methods to support the development of a reliable in vitro approach. Two BSFL-based mixes were tested: one with a higher chitin content (H70), and the other with a lower chitin content and also presenting a more balanced essential amino acid profile (M70). Each replaced 60% of FM in experimental diets (H20 and M20, respectively) and were compared to a control diet containing no BSFL meal. Apparent digestibility coefficients (ADCs) were measured in vivo using chromium oxide (Cr₂O₃; 1%) as an inert marker. In vitro digestibility was assessed using the pH-stat method with shrimp hepatopancreas enzyme extracts. In vivo results showed that the M20 feed had significantly higher digestibility than the control (p <0.05), while no significant difference in protein ADC was observed among diets. In vitro results indicated that the H20 feed had lower digestibility than the control (p <0.05). The ranking of protein digestibility (Control ≥ M20 ≥ H20) was consistent between both methods. A satisfactory correlation was found between in vivo and in vitro protein digestibility (R² = 0.691), which improved substantially after adjusting the in vitro assay temperature to match in vivo conditions (R² = 0.864). These findings suggest that the pH-stat method is a promising tool for preliminary assessment of ingredient digestibility, more precisely protein digestibility, in shrimp diets. Moreover, industrial BSFL meal appears to be a viable protein source for replacing upto 60% of FM in shrimp feed formulations without compromising shrimp survival or digestibility.

This study aimed to determine the effect of dual-strains probiotic (DSP) consisting of Lactobacillus casei and Bacillus subtilis on bacterial metagenomic profile, gut physiology, and digestive enzyme levels of African catfish (Clarias gariepinus) infected by Aeromonas hydrophila. The ratio between L. casei and B. subtilis was 1:1 each with a density of 10⁸ CFU/mL. Catfish (n = 8 fish per tank, three replicates per treatment) were fed diets supplemented with 0%, 5%, 10%, or 15% DSP for 42 days. On the 35th day, selected groups were intraperitoneally challenged with A. hydrophila at a dose of 0.1 mL × 10⁸ CFU/mL. The observed parameters included bacterial counts and microbial profile in the gastrointestinal tract (analyzed using next-generation sequencing [NGS]), gut physiology, and digestive enzyme levels (amylase, lipase, and protease). The results showed that DSP supplementation increased both the abundance and diversity of gastrointestinal microbes, elevated digestive enzyme levels, and enhanced the number of goblet cells in the intestinal lining. The dominant microbial phyla observed in the control group were Fusobacteria and Pseudomonadota.

The production of live microalgae represents a major cost in the operation of bivalve hatcheries, as it is the primary food used for larval rearing. This study investigated whether dissolved glucose could reduce the reliance on live microalgae as a sole feed input without negatively affecting bivalve larval performance during the rearing of Greenshell™ mussels (Perna canaliculus). Larvae from a single spawning cohort were raised to Day 10 post-fertilisation and then split into two feeding treatments: (1) control, fed only live microalgae in a continuous flow-through system and (2) glucose treatment, fed live microalgae in a continuous flow-through system, which was interrupted for 2 h, daily during which 10 μg mL⁻¹ of glucose dissolved in seawater, with a 20 min tank flush before and after exposure. The larvae were raised to settlement, during which time growth, microalgae consumption, losses of larvae at screening, settlement success and stable isotope composition (δ¹³C and δ¹⁵N) were assessed. Under these experimental conditions, substituting microalgae with glucose for 2 h daily did not alter the performance or isotopic composition of the larvae despite substituting an estimated 8.3% of live feed. This result provides a foundation to further test and refine the delivery of soluble nutrients, like glucose, as a means to reduce operational costs in bivalve hatcheries.

Yellowfin seabream (Acanthopagrus latus) was basal fed supplemented with low (Mus1: 100 mg/kg) and high (Mus2: 200 mg/kg) doses of lysozyme (200 U/mg) diets, compared to a control group (Mus3: basal fed with no lysozyme) to evaluate lysozyme as an antibiotic alternative. Comprehensive analyses (composition, texture, histological, and untargeted metabolomics) revealed lysozyme promoted growth, muscle development, and flesh quality. Lysozyme supplementation enhanced ash and carbohydrate accumulation significantly (p  < 0.05). Fish in the Mus1 group showed larger muscle fibers and increased myotome density. Metabolomics identified significant shifts in organic acids, lipids, and aromatic compounds. Mus2 enhanced mucosal immunity and retinal accumulation, while reducing fat deposition. Mus1, with a lower lysozyme dose, showed enrichment of the tricarboxylic acid cycle (TCA) cycle activity, accumulating beneficial organic acids (citric and malic acid) and nutritionally critical fatty acids (EPA and DHA), improving muscle quality. This study provides valuable insights into the effects of dietary lysozyme supplementation on yellowfin seabream, with potential applications for optimizing aquaculture practices and identifying key biomarkers for fish health and growth to improve muscle quality and flavor.

This study aims to investigate the effects of potassium diformate (KDF) and sodium propionate (NaP) on gut digestive and immune functions, intestinal microbiota, and lipid metabolites of Trachinotus ovatus based on multiomics approach. Juvenile T. ovatus (initial weight: 8.65 ± 0.02 g) were subjected to a 56-day feeding regimen. Three isonitrogenous and isolipidic diets, including the control (CG), an additional 6.6 g/kg of KDF, and an additional 6.0 g/kg of NaP were fed to juvenile fish twice daily. Results showed that KDF and NaP supplementation significantly increased the activities of chymotrypsin (Chy), lipase (Lip), α-amylase (α-amy), creatine kinase (CK), Na⁺K⁺-ATPase (Na⁺K⁺-ATP), γ-glutamyl transferase (γ-GT), alkaline phosphatase (AKP), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and superoxide dismutase (SOD) as well as the expression level of Nrf2 (p < 0.05), while decreased the pH value, malondialdehyde (MDA) content and the mRNA level of Keap1 (p < 0.05). Dietary KDF and NaP markedly enhanced microbial α-diversity and induced significant shifts in microbiota composition through selective modulation of bacterial populations, such as Photobacterium, Mycoplasma, and Mycobacterium (p < 0.05). Besides, KDF and NaP led to notable alterations in the intestinal metabolite lipidome through increasing short-chain fatty acids (SCFAs) levels, upregulating the abundance of phosphatidylcholine (PC), phosphatidylethanolamine, methyl PC (MePC), lysophosphatidic acid, ceramide (Cer), sitosteryl, monogalactosyldiacylglycerol, coenzyme, and lysophosphatidylethanolamine and downregulating the abundance of sphingomyelin and monoglyceride (p < 0.05). The assessment of associations revealed inverse relationships of digestive and antioxidative indices with Photobacterium, but positive correlations with Mycoplasma, Mycobacterium, Ruegeria, Synechococcus, Nautella, Turicibacter, and Roseovarius. This study advances our understanding of KDF and NaP on intestinal health.

Upcycling meat and fish by-products into bioactive protein hydrolysates promotes zero-waste practices within the circular bioeconomy and provides locally-sourced alternatives to replace fishmeal (FM) in aquafeeds. In this study, novel hydrolysates were developed from blue shark skin, fish by-products, and swine processed animal protein, aiming to reduce the high-quality FM inclusion in European seabass (Dicentrarchus labrax) diets. Four isoproteic (53%) and isolipidic (18%) plant-based diets were formulated: a control (CTRL) diet containing 12.5% FM was compared to three experimental diets, including 3% of each hydrolysate at the expense of FM-protein: SHARK, FISH, and SWINE. Seabass juveniles (13 g) stocked in 160 L tanks (3.9 kg/m³) were fed the diets in triplicate, three times daily until satiety, for 89 days. All diets were equally well accepted, promoting similar feed intake, daily growth index (1.6), and efficient feed conversion ratio (1.0–1.1). All fish at least quadrupled their initial size, but those fed the SWINE diet showed the highest body weight (55 g) and significantly higher condition factor (1.22), hepatosomatic index (HSI) (1.6), and viscerosomatic index (VSI) (8.4). Intestinal integrity remained similar across treatments, and apparent digestibility coefficients (ADCs) of protein and fat were above 96%. Iron (Fe) ADC was at least doubled with hydrolysates inclusion. Whole-body and muscle composition were similar across groups. However, the muscle metabolome of the SHARK-fed fish exhibited higher levels of glycolytic intermediates and lower levels of glucogenic amino acids (AAs) and fumarate, suggesting an increased catabolic activity. However, these changes were not reflected in fish growth performance or muscle flesh quality, which remained similar among treatments.

Metabolic responses to different dietary levels of vitamin D₃ and available phosphorus (avP) was investigated in cultured Atlantic salmon (Salmo salar). The study was carried out in triplicate with a 2-level full factorial design with a center point and three additional points within the design space. Over a 17- week period at the initial weight of 453 ± 9 g, salmon reared indoor on land, were fed diets containing different levels of vitamin D₃ and avP. In summary,growth performance, measured as specific growth rate (SGR), improved when either vitamin D₃ or avP was increased independently, but declined when both were elevated excessively. Bone mineralization was maintained at intermediate vitamin D₃ inclusion levels, though high vitamin D₃ reduced bone ash. A diet containing 0.63 mg/kg vitamin D₃ and 0.70% avP supported growth and mineral retention. A significant reduction in fecal soluble phosphorus when vitamin D₃ was increased in the diet, suggests that management of vitamin D₃ can contribute to improved waste control and reduced environmental load for phosphorus. Finally, the study highlighted that today’s commercial dietary inclusion of vitamin D₃ can result in lower vitamin D₃ accumulation in muscle of land-based farmed Atlantic salmon compared to wild Atlantic salmon.

The optimum period for feeding a broodfish diet combined with manipulated ovulation time, has recently been investigated for egg production capacity, as well as egg and juvenile quality in Atlantic salmon. Here, we report the status of vitamins C, E, D, and K in fish from the same experiment to ensure requirements were met. Two-sea-winter female broodfish were followed through a 17-month growth period, a starvation period on-land until ovulation, and offspring until first-feeding. Throughout all periods, the impact of 9 vs. 17 months of broodfish feed, and early (November), normal (December), and late (February) ovulation on vitamin status was monitored. Vitamin deposition increased with growth, with muscle depositing the highest amounts due to its size. Once the gonads matured, vitamins E, K, and D were similar to muscle, while C was higher. Livers had the highest C, E, and K concentrations, while D was comparable across tissues. During starvation, body stores of C, K, and D declined, while E remained high. All studied vitamins except for C followed the general nutrient deposition profile in unfertilized eggs, increasing from early to late ovulation. K1 was depleted as menaquinone-4 rose, suggesting possible conversion in broodfish and offspring. Ovulation time affected vitamin status more than feeding regime. Vitamin C, E, and most likely K and D levels in both feeding regimes covered the requirements for broodfish and first-feeding fry, regardless of ovulation treatment. However, both early and late eggs and juveniles were of inferior quality, suggesting factors beyond the vitamins examined influenced reproductive outcomes.

Ammonia stress (AS) constitutes a significant environmental challenge that impedes aquaculture development. In this investigation, histomorphology assessments, physiological, and biochemical parameter analyses, and multiomics approaches were employed to elucidate the impact of acute AS on yellow catfish (Pelteobagrus fulvidraco). Findings indicated that serum ammonia concentrations exhibited a dose-dependent increase, correlating with the intensity and duration of stress. As the primary detoxification organ, the liver facilitates ammonia clearance by upregulating genes involved in glutamine and ureagenesis (glutamine synthase [gs], carbamoyl-phosphate synthase [cps], ornithine transcarbamylase [otc], argininosuccinate lyase [asl], argininosuccinate synthase [ass], arginase [arg]), thereby promoting glutamine and ureagenesis while consuming glutamate, argininosuccinic acid, aspartic acid, arginine, and adenosine triphosphate (ATP). Physiological and biochemical data revealed that AS significantly elevated serum glucose, liver triglyceride (TG), and total cholesterol (TC) levels. Histological examination demonstrated a marked reduction in liver glycogen stores alongside a progressive accumulation of lipid droplets proportional to stress severity, suggesting activation of liver glycogenolysis coupled with suppression of lipolysis. Integrative transcriptomic and metabolomic analyses indicated a reprograming of liver energy metabolism characterized by enhanced glycogenolysis and suppressed lipogenesis: liver glycogen content decreased, key glycolytic gene expression (hk1, pdhx) was downregulated, and tricarboxylic acid (TCA) cycle flux was diminished due to decreased cs expression. Concurrently, transcription of fatty acid β-oxidation enzymes (acsbg1, cpt1) was suppressed, leading to palmitic acid accumulation and impaired lipid-derived energy production. Nonetheless, reorganization of carbon flux through upregulation of mdh2 and idh1 facilitated pyruvate utilization in the TCA cycle, promoting NADH generation and sustaining oxidative phosphorylation, as evidenced by increased ATP turnover and content. This study elucidates the metabolic response to AS via increased glycogenolysis. Optimizing liver glycogen reserves serves as a nutritional strategy to enhance ammonia tolerance. Targeted regulation of key genes (pygl, pk, mdh2, idh1) to promote glycogen–pyruvate metabolism may mitigate ammonia toxicity effects and improving aquaculture productivity.