Aquaculture Nutrition最新文献

Use of corn-fermented protein (CFP), a new product produced using Fluid Quip Technologies, as a protein source in aquaculture feeds, constitutes a promising option due to its dependable supply and cost-effectiveness. In this study, two growth trials were performed to evaluate the effectiveness of CFP products such as CFPA (48% crude protein [CP]), CFPB1 (50% CP), and CFPB2 (60% CP) from two different sources (A and B) in practical diets for juvenile Pacific white shrimp (Litopenaeus vannamei). The test diets in both trials were formulated to be isonitrogenous and isolipidic (36% crude protein and 6% crude lipid). These diets were produced by supplementing the basal diet with 5%, 10%, 15%, and 20% CFPA or 4%, 8%, 12%, and 16% of CFPB1 and CFPB2 to replace soybean meal (SBM) on an isonitrogenous basis. In a 6-week experiment, shrimp (1.02 ± 0.02 g mean weight, 15 shrimp per tank, n = 6) were offered CFPA diets. Growth parameters and protein retention showed no significant differences among diets. However, a significant feed conversion ratio (FCR) increase was observed when shrimp were fed a diet containing 20% CFPA compared to the basal and 5% CFPA diets. Physiological gene expression analysis revealed no signs of gut inflammation or shifts in hepatopancreas digestive enzymes (p  > 0.05). However, the expression of immune-related tnf-α gene was significantly upregulated (p  < 0.05) in shrimp-fed CFPA 25% diet compared to CFPA 5% and control groups. In a 7-week experiment, shrimp (0.55 ± 0.01 g, 15 shrimp per tank, n = 5) received experimental CFPB1 or CFPB2 diets. No differences were observed in growth performance. This research highlights the potential of CFP as a protein source in shrimp diets by expanding the range of feed ingredients and identifying optimal inclusion levels.

This study evaluates the potential of microalgae, Chlorella vulgaris, and black soldier fly larvae (BSFL), Hermetia illucens, as an alternative complete diet for red hybrid tilapia, addressing challenges arising from declining fish stocks and unsustainable aquaculture practices reliant on fish meal in commercial pellets. The study involved 270 tilapia separated into three groups: Group 1 received C. vulgaris alone, Group 2 was fed with a combination of BSFL and C. vulgaris, and Group 3 with commercial pellets (control) for 70 days. The results demonstrated that the combination of BSFL and C. vulgaris had a high potential to be an alternative to commercial pellets, with comparable growth performance with the control group. In contrast, fish-fed with C. vulgaris alone exhibited significantly slower growth rates and higher mortality. Economic analysis showed that the BSFL and C. vulgaris combination reduced feed costs by 59.40% and increased the profit index by 144.79% compared to the control group. However, the combination diet did not provide significant protection against streptococcosis compared to commercial pellets. This study highlights the potential of incorporating BSFL and C. vulgaris into tilapia diets to enhance sustainability and economic outcomes for farmers. It also emphasizes the role of alternative feeds in promoting environmentally sustainable aquaculture practices, with the goal of achieving zero-carbon emissions. This study is the earliest report on the direct combination of BSFL and C. vulgaris diet in tilapia, a globally cultivated aquaculture fish species.

This study evaluated the effects of dietary synthetic astaxanthin (SA), Haematococcus pluvialis (HP) and Phaffia rhodozyma (PR) on the growth performance, antioxidant activity, innate immunity, morphology, and pigmentation of juvenile Litopenaeus vannamei. Shrimp (1.15 ± 0.01 g) were fed with the control diet and astaxanthin diets containing 20 mg/kg of astaxanthin from three sources (SA, HP, and PR) for 56 days. The results indicated that, compared with the control group, growth performance was observably elevated in the HP and PR groups (p < 0.05). The astaxanthin (SA, HP, and PR) supplemented diets markedly elevated the activities of glutathione peroxidase (GPx) and GST in the intestine and hepatopancreas (p < 0.05), while observably reduced the MDA content (p < 0.05). The apoptosis rates in three astaxanthin groups were noticeably reduced in comparison with the control group (p < 0.05). Dietary astaxanthin (SA, HP, and PR) observably elevated the expression of the Toll, IMD, and CAT genes in the hepatopancreas (p < 0.05). Besides, dietary astaxanthin (SA, HP, and PR) noticeably improved the astaxanthin accumulation and pigmentation of shrimp (p < 0.05). The survival rates of shrimp challenged with Aeromonas hydrophila were markedly higher in the astaxanthin groups than in the control group (p < 0.05), and no significant difference was detected among three astaxanthin groups (p > 0.05). Moreover, our results suggested that natural astaxanthin (HP and PR) was more effective for enhancing growth and antioxidant capacity of shrimp. Nevertheless, no marked difference was detected between natural astaxanthin and SA in coloration performance and disease resistance.

The rapid expansion of aquaculture in Bangladesh has played a vital role in meeting the increasing demand for fish protein. However, the industry faces significant challenges due to the high cost and environmental impact of fishmeal (FM), a primary protein source in aquafeeds. This review critically evaluates alternative protein sources for aquafeeds, including plant-based proteins, insect meals, agricultural by-products, and single-cell protein (SCP), with a focus on their applicability in the Bangladesh context. Using the Joanna Briggs Institute (JBI) methodology, we synthesized evidence from peer-reviewed studies and institutional reports to assess the nutritional profiles of these alternatives. Results show that while plant-based proteins are affordable and locally available, they require processing to reduce antinutritional factors (ANFs). Insect meals exhibit high protein content and feed efficiency, with a primary focus on their essential amino acids (EAAs) profiles, which are crucial for optimal fish growth, immunity, and metabolic performance. Agricultural wastes such as fruit peels and vegetable residues offer cost-effective and immune-boosting properties, while SCP derived from algae, fungi, yeast, and bacteria emerge as a nutritionally robust and environmentally sustainable option. Despite the promise of these alternatives, limitations persist in terms of nutrient imbalances, processing requirements, and scalability. Overcoming these barriers demands targeted research and development, policy support, and investment in local feed innovation to ensure sustainable aquaculture growth. This study underscores the critical need for further research and strategic implementation of alternative feed resources to enhance the sustainability, profitability, and resilience of aquaculture in Bangladesh, with a focus on optimizing inclusion levels, improving digestibility, and utilizing locally available ingredients to ensure nutritional balance and food security.

The present study evaluated the effectiveness of five dietary additives in improving growth performance, gut and skin health and disease resistance against Photobacterium damselae subsp. damselae (Pdd) in yellowtail kingfish (YTK) (Seriola lalandi). The additives were top-coated onto a commercial diet. The five additives evaluated were brewer’s yeast (BY), a yeast-based mannan oligosaccharide (MOS), a polyphenol product, a monoglyceride product and a combination of MOS and a superoxide dismutase (SOD) product. The monoglyceride and polyphenol products were trialled at both a low and high inclusion level. Diets were fed to YTK in triplicate tanks for 55 days. The results found that growth, feed utilisation and somatic indices were unaffected by additive inclusion. None of the additives affected the health of YTK liver, skin or the gut as determined by various histological metrics. These histological findings were supported by results of hindgut gene expression (TNF-α, IL-10, Hsp70, mucin 2 and i-mucin and SOD), all of which were unchanged across the dietary treatments. Similarly, the additives did not stimulate the skin mucus quantity and skin mucosa barrier measurements (epidermis thickness and mucus cells), consistent with the results of relevant skin health gene expression measurements (TNF-α, IL-8, calreticulin, Hsp70, mucin 2, CAT and SOD). However, the MOS and low inclusion polyphenol treatments increased survival against Pdd challenge relative to control treatment. The immuno-modulating capacity of the polyphenol product was indicated by the absence of Pdd in faeces following a mucosal (bathe) challenge at the high inclusion; however, this did not translate to enhanced survival under systemic infection. However, further studies are needed to understand if optimisation of the inclusion levels of each additive might more strongly influence the health of YTK.

The purpose of this study was to evaluate the effects of baker’s yeast (Saccharomyces cerevisiae) supplementation on growth, immune-related gene expression, and disease resistance in Nile tilapia (Oreochromis niloticus) during the winter season. Fish (an average 5.17 ± 0.33 g) were fed diets containing four different S. cerevisiae concentrations: 0 g/kg (control; T1), 5 g/kg (T2), 10 g/kg (T3), and 20 g/kg (T4) for 90 days. The results showed that weight gain (WG) and specific growth rate (SGR) were significantly higher in fish-fed the T4 diet compared to the control group (p < 0.05). Additionally, fish-fed the T4 diet showed lower carcass yields but higher fillet yields, along with increased amylase and protease activities (p < 0.05). Significant increases (p < 0.05) in serum lysozyme activity were found in fish-fed the T4 supplemented diet, and elevated myeloperoxidase (MPO) levels were observed in fish-fed the T3 diet. Moreover, upregulation of il-8 transcription in the liver was noted in fish feeding S. cerevisiae (T2–T4) compared to the control group. In a challenge test against Streptococcus agalactiae, survival rates (SRs) were significantly higher in fish-fed the T4 diet compared to the control group (p < 0.05). Interestingly, the lowest bacterial counts were recorded in the T3 group (p < 0.05). These findings suggest that dietary supplementation with S. cerevisiae at 10–20 g/kg enhances growth performance, digestive enzyme activity, immune responses, and disease resistance in Nile tilapia during winter conditions.

Study of precision nutrition provides essential and accurate information on the nutrient requirements for animal growth under various farming modes, to offer guidance for the efficient utilization of compound feed. To evaluate the effects of dietary protein levels on the growth performance, immune response, and health of Macrobrachium rosenbergii reared under high-density conditions, prawns in five groups were cultured with a density at 70 prawns/m³, and fed diets with varying protein levels (40%, 42.5%, 45%, 47.5%, and 50%) and designated as CP40, CP42.5, CP45, CP47.5, and CP50, respectively. Our findings revealed that the prawns in the CP42.5 and CP45 groups exhibited significantly higher weight gain rates and specific growth rates, whereas the feed conversion ratio (FCR) was significantly lower in these groups (p < 0.05). The hepatosomatic index (HSI) of prawns in the CP45 group was significantly higher than the other treatments (p < 0.05). The trypsin activity in the CP45 group was the highest (p < 0.05). Additionally, prawns fed 42.5%–45% protein levels exhibited stronger antioxidant capacity (AOC), with higher total antioxidant capacity (T-AOC), and the activities of catalase (CAT), total superoxide dismutase (T-SOD), and glutathione S-transferase (GST) (p < 0.05), along with a substantial reduction in protein carbonyl (PC) levels (p < 0.05). Analysis of the expression of apoptosis-related genes and hematoxylin-eosin staining revealed that both insufficient and excessive dietary protein levels significantly led to autophagy in the hepatopancreas. The environmental stress tests demonstrated that the survival rate (SR) of prawns in the CP45 group was significantly higher compared to the other treatments (p < 0.05). From a growth and health perspective, our findings revealed that a 42.5%–45% protein level is appropriate for M. rosenbergii cultured under high-density (70 prawns/m³) conditions.

The effects of graded levels of hydrolyzed yeast (HY) supplementation (0.0, 0.5, 1.0, and 2.0 g/kg, i.e., Control, HY0.5, HY1.0, HY2.0, respectively) on growth performance, gut health, and immune responses of juvenile Nile tilapia (Oreochromis niloticus) were assessed in this study. The experiment was conducted in a completely randomized design for 14 weeks, where the treatments were distributed in 16 300-L tanks with four replicates each. Despite no significant differences, the final body weight and weight gain were numerically higher in treatments containing HY (44.7 and 34.7 g, 43.5 and 33.5 g, and 45.5 and 35.5 g in HY0.5, HY1.0, and HY2.0, respectively). Feed efficiency (FE) was improved linearly (p < 0.05) with increasing dietary HY level (0.65, 0.70, and 0.72, respectively). Similarly, there was also a significant linear relationship between protein deposition (PD), as well as protein and energy retention efficiency (ERE), with the increasing dietary HY level. Among the blood parameters, only the hematocrit (HCT) value was significantly lower in HY1.0 and HY2.0 compared to the control and HY0.5 treatments. Gut histology showed significantly higher villi length in fish fed HY2.0 diets (795 ± 89.6 µm) compared to those fed the control diet (504 ± 80.7 µm). The average surface volume (SV) of the villi was also higher in tilapia fed HY0.5, HY1.0, and HY2.0 diets (0.025, 0.026, and 0.038 mm³, respectively) compared to the control diet (0.021 mm³). All four target genes were significantly upregulated in HY1.0 and HY2.0 treatments. The expression of the genes supporting growth and ATP production, insulin-like growth factor-1 (IGF-1) and glyceraldehyde-3-phosphate (G-3-P), respectively, was significantly improved, as well as the expression of the immune-related gene, hepcidin. The expression of ghrelin also showed a significant increase with increasing HY levels. It can be concluded that the HY supplementation improved feed utilization, gut health, nutrient absorption capacity, and immunity in Nile tilapia.

An 8-week feeding trial was conducted to assess the effects of hydrolyzed feather meal (HFM) as a fish meal replacement on the growth performance, flesh quality, skin color, and intestinal microbiota of yellow catfish (Pelteobagrus fulvidraco). Five isonitrogen (44% crude protein) and isolipidic (8.5% crude lipid) diets were formulated with varying levels of HFM at 0% (FM, control), 2.05% (HFM2), 4.10% (HFM4), 6.15% (HFM6), and 8.20% (HFM8), corresponding to fish meal replacement of 0%, 8.33%, 16.67%, 25%, and 33.33%, respectively. Results indicated that the growth performance declined significantly as HFM inclusion increased. Based on the results of weight gain rate (WGR) and specific growth rate (SGR), the maximal replacement levels of fish meal with HFM for yellow catfish should be 16.67%. Intestinal enzyme activities, including trypsin, lipase, amylase, and Na⁺–K⁺–ATPase as well as villus height, muscular thickness, and goblet cells number were significantly enhanced in HFM groups. Fish meal replacement with HFM remarkably reduced serum immune indicators acid phosphatase, immunoglobulin M, Complement 3, and Complement 4 levels and significantly increased serum aspartate aminotransferase, total triglycerides, and cholesterol levels, indicating compromised immune function and liver health. The content of collagen and flavor-enhancing amino acids (glutamic acid [Glu], glycine [Gly], and alanine [Ala]), as well as muscle hardness were distinctly boosted, demonstrated an elevated flesh texture led by dietary HFM inclusion. The abnormal skin coloration induced by pigmentary disorders was observed in high HFM inclusion groups, the black pigmentation on dorsal and yellow pigmentation on the abdomen exhibited a gradual reduction in intensity. The study found that replacing up to 16.67% of fish meal with HFM in yellow catfish diets maintained growth performance and improved meat quality. However, high HFM levels damaged serum immune system and caused liver dysfunction, dyslipidemia, pigmentary disorders, and reshaped intestinal microbial structure.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential component in regulating oxidative stress. Sulforaphane (SFN) is a natural antioxidant and gene Nrf2 agonist that can increase the antioxidant capacity of the organism and reduce oxidative stress. However, research on the repair of oxidative stress damage by SFN in aquatic animals remains extremely scarce. In order to further explore the function and role of SFN in the repair of oxidative stress injury in aquatic animals, this study took Litopenaeus vannamei as the research object. We established an oxidative stress model of L. vannamei through 6% oxidized fish oil (OFO) feeding. Methods, such as RNA interference (RNAi), qPCR, histopathological analysis, and TUNEL assay, were used to detect the changes in the oxidative stress status of L. vannamei. The results showed that the expression of Nrf2 in the hepatopancreas of L. vannamei in the double-stranded RNA (dsRNA)-Nrf2 + SFN group was significantly higher than that in the dsRNA-Nrf2 group and control group at 24 h (p < 0.05). The transcription levels of antioxidant and autophagy genes in the SFN group were significantly higher than those in the control group (p < 0.05), and the expression of related genes in the dsRNA-Nrf2 + SFN group was also higher than that in the dsRNA-Nrf2 group. Histopathology showed that Nrf2 knockdown would aggravate hepatopancreatic apoptosis and vacuolation, while SFN treatment after Nrf2 knockdown could alleviate hepatopancreatic injury and apoptosis caused by OFO. The results indicated that SFN could repair the oxidative stress injury of L. vannamei induced by OFO by activating Nrf2. This study investigated the role of SFN in alleviating and repairing the oxidative stress damage in L. vannamei caused by OFO, aiming to provide a theoretical basis for the research on the antioxidant effect of SFN and the regulation of the antioxidant capacity of shrimp.