Browsing by Author "Yi-Chan Liu"

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    Dietary docosahexaenoic acid reduces fat deposition and alleviates liver damage induced by D-galactosamine and lipopolysaccharides in Nile tilapia (Oreochromis niloticus)
    (Elsevier, 2023-06) Yi-Chan Liu; Samwel Mchele Limbu; Jin-Gang Wang; Mai Wang; Li-Qiao Chen; Fang Qiao; Yuan Luo; Mei-Ling Zhang; Zhen-Yu Du
    Liver health is important to maintain survival and growth of fish. Currently, the role of dietary docosahexaenoic acid (DHA) in improving fish liver health is largely unknown. This study investigated the role of DHA supplementation in fat deposition and liver damage caused by D-galactosamine (D-GalN) and lipopolysaccharides (LPS) in Nile tilapia (Oreochromis niloticus). Four diets were formulated as control diet (Con), Con supplemented with 1 % DHA, 2 % DHA and 4 % DHA diets, respectively. The diets were fed to 25 Nile tilapia (2.0 ± 0.1 g, average initial weight) in triplicates for four weeks. After the four weeks, 20 fish in each treatment were randomly selected and injected with a mixture of 500 mg D-GalN and 10 μL LPS per mL to induce acute liver injury. The results showed that the Nile tilapia fed on DHA diets decreased visceral somatic index, liver lipid content and serum and liver triglyceride concentrations than those fed on the Con diet. Moreover, after D-GalN/LPS injection, the fish fed on DHA diets decreased alanine aminotransferase and aspartate transaminase activities in the serum. The results of liver qPCR and transcriptomics assays together showed that the DHA diets feeding improved liver health by downregulating the expression of the genes related to toll-like receptor 4 (TLR4) signaling pathway, inflammation and apoptosis. This study indicates that DHA supplementation in Nile tilapia alleviates the liver damage caused by D-GalN/LPS through increasing lipid catabolism, decreasing lipogenesis, TLR4 signaling pathway, inflammation, and apoptosis. Our study provides novel knowledge on the role of DHA in improving liver health in cultured aquatic animals for sustainable aquaculture.
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    Dietary L-carnitine alleviates the adverse effects caused by reducing protein and increasing fat contents in juvenile largemouth bass (Micropterus salmoides)
    (2022-05-06) Yi-Chan Liu; Samwel Mchele Limbu; Jin-Gang Wang; Jiong Ren; Fang Qiao; Mei-Ling Zhang; Zhen-Yu Du
    Protein ingredients for formulation of fish feeds are expensive and have limited availability. Therefore, reducing dietary protein while increasing dietary fat content is a common practice in rearing carnivorous fish species. However, the ability of dietary L-carnitine to alleviate adverse effects in such diets is currently unknown. This study investigated the role of L-carnitine supplementation in alleviating adverse effects on growth performance, energy metabolism, antioxidant capacity, and inflammation response in juvenile largemouth bass (Micropterus salmoides) fed on a low protein and high fat diet. Three diets were formulated to contain low protein and high fat (LPHF: 420 g kg-1 protein and 150 g kg-1 lipid), LPHF supplemented with L-carnitine (LPHFC: 420 g kg-1 protein and 150 g kg-1 lipid), and a control diet (CON: 480 g kg-1 protein and 130 g kg-1 lipid). The diets were fed to 30 largemouth bass (g) juveniles in triplicates for eight weeks. The results showed that the fish feed on LPHF diet increased hepatosomatic index, visceral somatic index, mesenteric fat index, whole-body crude fat content, serum and liver triglyceride concentrations, and serum non-esterified fatty acid level than those fed on CON diet. Moreover, the fish fed on LPHF diet increased serum alanine aminotransferase activity and liver malondialdehyde content and reduced superoxide dismutase (SOD) activities in the serum and liver. Furthermore, the fish fed on LPHF diet reduced the whole-body crude protein content. Interestingly, feeding the fish on the LPHFC diet decreased fat deposition and liver damage by downregulating the expression of genes related to lipogenesis, inflammation, and increased SOD activity. This study indicates that L-carnitine supplementation in largemouth bass alleviates the adverse effects caused by LPHF diet by decreasing lipogenesis and increasing lipid catabolism. Our study provides novel knowledge on strategies to improve utilization of LPHF diet in cultured aquatic animals.
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    Vitellogenin 1 is essential for fish reproduction by transporting DHA-contained phosphatidylcholine from liver to ovary
    (Elsevier, 2023-04) Sheng-Xiang Sun; Yi-Chan Liu; Samwel Mchele Limbu; Dong-Liang Li; Li-Qiao Chen; Mei-Ling Zhang; Zhan Yin; Zhen-Yu Du
    Vitellogenins (Vtgs) are essential for female reproduction in oviparous animals, yet the exact roles and mechanisms remain unknown. In the present study, we knocked out vtg1, which is the most abundant Vtg in zebrafish, Danio rerio via the CRISPR/Cas 9 technology. We aimed to identify the roles of Vtg1 and related mechanisms in reproduction and development. We found that, the Vtg1-deficient female zebrafish reduced gonadosomatic index, egg production, yolk granules and mature follicles in ovary compared to the wide type (WT). Moreover, the Vtg1-deficient zebrafish diminished hatching rates, cumulative survival rate, swimming capacity and food intake, but increased malformation rate, and delayed swim bladder development during embryo and early-larval phases. The Vtg1-deficiency in female broodstock inhibited docosahexaenoic acid-enriched phosphatidylcholine (DHA-PC) transportation from liver to ovary, which lowered DHA-PC content in ovary and offspring during larval stage. However, the Vtg1-deficient zebrafish increased gradually the total DHA-PC content via exogeneous food intake, and the differences in swimming capacity and food intake returned to normal as they matured. Furthermore, supplementing Vtg1-deficient zebrafish with dietary PC and DHA partly ameliorated the impaired female reproductive capacity and larval development during early phases. This study indicates that, DHA and PC carried by Vtg1 are crucial for female fecundity, and affect embryo and larval development through maternal-nutrition effects. This is the first study elucidating the nutrient and physiological functions of Vtg1 and the underlying biochemical mechanisms in fish reproduction and development.