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Aquaculture has become the largest source of seafood consumption, leading to increased research in aqua-nutrition. A survey of publications on aqua-nutrition topics was conducted, revealing that feed additives are the most studied area due to the need for alternatives to antibiotics. Plant extracts and microbial agents are popular feed additives, with a focus on natural and green options. Research on alternative protein and lipid sources, such as insects and microalgae, is also prominent. The study emphasizes the importance of considering the demands of the aquaculture industry and market in aqua-nutrition research. [Extracted from the article]

A 65‐day feeding trial was conducted to investigate the effects of different levels of dietary lipid on intestinal health of tiger puffer. Three experimental diets were formulated, differing in lipid level, that is, 90.3 (control‐suitable lipid, C‐SL), 130.3 (moderately high lipid, MHL) and 170.3 (extremely high lipid, EHL) g/kg dry matter. The results showed that with increasing dietary lipid levels, the activities of total antioxidant capacity, Na+ K+‐ATP, amylase and trypsin were significantly decreased by diets MHL and EHL. Compared with C‐SL, the mRNA expression of the intestinal tight junction proteins (Claudin14, Claudin18, junctional adhesion molecule‐A) were significantly down‐regulated and the serum diamine oxidase enzyme activity was significantly increased in the EHL group. Diet EHL up‐regulated the gene expression of the pro‐inflammatory cytokines, tumour necrosis factor‐α, interferon‐2, interleukin (IL)‐1β, IL‐8 and IL‐15, and down‐regulated that of anti‐inflammatory cytokine transforming growth factor ‐β. Sequencing of intestinal bacterial 16s rRNA V4 region showed that diet EHL significantly increased the Firmicutes/Bacteroidetes ratio, decreased the alpha diversity of intestinal microbiota and the relative abundance of some potential beneficial bacteria such as Lactobacillus, Sphingomonas and Thermus. These results showed that high level of dietary lipid (170.3 g/kg) had negative effects on function status, mucosal barrier and microbial communities of tiger puffer intestine, indicating that tiger puffer was sensitive to the dietary lipid level. [ABSTRACT FROM AUTHOR]

A 63-day feeding trial was conducted to evaluate the effect of Clostridium autoethanogenum protein (CAP) on the growth, digestibility, postprandial free amino acid concentrations in serum, and gene expression related to protein metabolism in obscure pufferfish (Takifugu obscurus). The basal diet with 420 g/kg of fishmeal was used as the control diet (CAP0), and then 20 % (CAP20), 40 % (CAP40) and 80 % (CAP80) dietary fishmeal were replaced by CAP. Compared with diet CAP0, the growth and feed utilization was not affected in fish fed diet CAP20, but was significantly reduced in fish fed diets CAP40 and CAP80 (P < 0.05). The apparent digestibility coefficients (ADCs) of dry matter and protein in the CAP80 group were significantly lower (P < 0.05) than those of the other three groups, and the ADC of lipid was significantly decreased (P < 0.05) in the CAP40 and CAP80 groups. Fish fed diets CAP40 and CAP80 had lower taurine content in muscle compared to those fed diets CAP0 and CAP20 (P < 0.05). Higher free essential amino acid concentrations in serum were observed in fish fed diet CAP80 compared to the other diets at 2 h after refeeding (P < 0.05). Fish fed diets CAP40 and CAP80 showed lower hardness and gumminess in muscle than those fed the other diets (P < 0.05). The expression of peptide transporter1 (PepT1) in intestine and target of rapamycin (TOR) in muscle were significantly up-regulated in the CAP40 groups compared to the control (CAP0) (P < 0.05). However, relative expressions of 4F2 heavy chain (4F2hC), L-type amino acid transporter 2 (y+LAT2) and T-type amino acid transporter1(TAT1) in intestine were not significantly affected by graded levels of CAP (P > 0.05). The inclusion of CAP did not significantly affect the expression of ribosomal protein S6 kinase 1 (S6K1), eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) and 4E-BP2 (P > 0.05) in muscle and liver. In summary, in a basal diet containing 420 g/kg fishmeal, 20 % fishmeal in diets could be successfully substituted by CAP, while high-level CAP decreased the growth, feed utilization and digestibility in juvenile obscure pufferfish. The main reasons for the inhibition of growth performance were probably that excessive CAP caused dietary taurine deficiency and the imbalance of amino acid absorption. • CAP can partially substitute fishmeal without negative effects on growth and feed utilization in obscure pufferfish. • Fishmeal replacement by CAP significantly up-regulated the expressions of TOR and PepT1 at transcriptional level. • Excessive CAP may cause dietary taurine deficiency and the imbalance of amino acid absorption. [ABSTRACT FROM AUTHOR]

Vibrio genus is a common pathogen in aquaculture and causes acute hepatopancreatic necrosis disease (AHPND) and massive mortality of shrimp. Many studies have suggested that a single functional ingredient such as plant extract or organic acid can reduce the dependence on antibiotics and promote the growth and immunity of aquatic animals. In this study, we evaluated the effects of a phytobiotic-based compound additive (Sanacore® GM, SNGM), which had a successful trajectory of commercial application in fish farming. However, its effects on the hepatopancreas health and intestinal microbiota of shrimp after Vibrio challenge have not been well evaluated. In the present study, Pacific white shrimp were fed diets with or without supplementation of SNGM, and the SNGM grades were 0-g/kg (CON), 3-g/kg (SNGM3), and 5-g/kg (SNGM5) diets. The feed trial lasted 60 days, after which a Vibrio parahaemolyticus challenge was performed. The results showed that compared to the CON group, both the SNGM3 and SNGM5 groups had a significantly higher weight gain and a lower feed conversion ratio as well as higher survival after Vibrio parahaemolyticus challenge. In the growth trial, the SNGM3 group had a significantly increased total protein, albumin concentration, and acid phosphatase activity in hemolymph compared to the CON group. In the challenge experiment, the SNGM3 and SNGM5 groups had increased albumin and glucose contents as well as the activities of phenoloxidase, lysozyme, alkaline phosphatase, and superoxide dismutase in hemolymph. Both the SNGM3 and SNGM5 groups had improved morphology of the hepatopancreas and intestine. The SNGM5 group had alleviated gut microbiota dysbiosis induced by Vibrio infection by increasing the potential probiotic bacterium abundance ( Shewanella ) and decreasing the potential pathogenic bacteria abundance ( Vibrio , Photobacteriuma , Pseudoalteromonas , and Candidatus&#95;Bacilloplasma ). In conclusion, the dietary phytobiotic-based additive at 3-g/kg level increased the growth and Vibrio parahaemolyticus resistance of Pacific white shrimp by promoting immune-related enzyme activities and improving the morphological structure of the hepatopancreas and intestine and the intestinal microbiota composition., Competing Interests: Authors GZ, I-TC, and WN-O were employed by the company Adisseo Life Science Shanghai Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ma, Zhao, Liu, Chen, Wei, Liang, Dai, Nuez-Ortin and Xu.)