Dataset Information

The Benefit of Optimal Dietary Lipid Level for Black Seabream Acanthopagrus schlegelii Juveniles under Low-Salinity Environment.

ABSTRACT: The present study was aimed at evaluating the regulatory effects of dietary lipid levels on growth performance, osmoregulation, fatty acid composition, lipid metabolism, and physiological response in Acanthopagrus schlegelii under low salinity (5 psu). An 8-week feeding trial was conducted in juvenile A. schlegelii with an initial weight of 2.27 ± 0.05 g, and six isonitrogenous experimental diets were formulated with graded levels of lipid: 68.7 g/kg (D1), 111.7 g/kg (D2), 143.5 g/kg (D3), 188.9 g/kg (D4), 239.3 g/kg (D5), and 269.4 g/kg (D6), respectively. Results indicated that fish fed with diet containing 188.9 g/kg lipid significantly improved growth performance. Dietary D4 improved ion reabsorption and osmoregulation by increasing the concentrations of Na⁺, K⁺, and cortisol in serum and activities of Na⁺/K⁺-ATPase as well as expression levels of osmoregulation related to gene expression levels in the gill and intestine. The expression levels of long chain polyunsaturated fatty acid biosynthesis-related genes were dramatically upregulated when dietary lipid levels increased from 68.7 g/kg to 189.9 g/kg with levels of docosahexaenoic (DHA), eicosapentaenoic (EPA), and DHA/EPA ratio being highest in the D4 group. When fish fed dietary lipid levels from 68.7 g/kg to 188.9 g/kg, lipid homeostasis could be maintained by upregulating sirt1 and pparα expression levels, whereas lipid accumulation was observed in dietary lipid levels of 239.3 g/kg and over. Fish fed with high dietary lipid levels resulted in physiological stress related to oxidative stress and endoplasmic reticulum stress. In conclusion, based on weight gain, the optimal dietary lipid requirement of juvenile A. schlegelii reared at low-salinity water is 196.0 g/kg. These findings indicate that the optimal dietary lipid level can improve growth performance, n-3 LC-PUFA accumulation, and osmoregulatory ability and maintain lipid homeostasis and normal physiological functions of juvenile A. schlegelii.

SUBMITTER: Jin M

PROVIDER: S-EPMC9973135 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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The Benefit of Optimal Dietary Lipid Level for Black Seabream Acanthopagrus schlegelii Juveniles under Low-Salinity Environment.

Jin Min M Li Xuejiao X Shen Yuedong Y Bao Yangguang Y Yang Bingqian B Wu Zhaoxun Z Jiao Lefei L Zhou Qicun Q

Aquaculture nutrition 20221011

The present study was aimed at evaluating the regulatory effects of dietary lipid levels on growth performance, osmoregulation, fatty acid composition, lipid metabolism, and physiological response in Acanthopagrus schlegelii under low salinity (5 psu). An 8-week feeding trial was conducted in juvenile A. schlegelii with an initial weight of 2.27 ± 0.05 g, and six isonitrogenous experimental diets were formulated with graded levels of lipid: 68.7 g/kg (D1), 111.7 g/kg (D2), 143.5 g/ ...[more]

PMID: 36860453

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Project description:An 8-week feeding trial was conducted to evaluate the effects of dietary carbohydrate to lipid (CHO:L) ratios on growth performance, muscle fatty acid composition, and intermediary metabolism in juvenile black seabream (Acanthopagrus schlegelii). Five isonitrogenous and isoenergetic diets (48.0% crude protein and 18.0 MJ kg-1 gross energy) were formulated to contain different CHO:L ratios ranging from 0.33 to 3.75. Triplicate groups of 20 fish averaging 0.51 ± 0.01 g were fed with experimental diets twice daily to apparent satiation. The results indicated that final body weight (FBW), percentage weight gain (PWG), specific growth rate (SGR), and protein efficiency ratio (PER) were significantly influenced by the dietary CHO:L ratios (p < 0.05). The highest FBW, PWG, and SGR were observed in fish fed the diet with a CHO:L ratio of 1.36 (p < 0.05). A two-slope broken-line regression analysis based on PWG indicated that the optimal dietary CHO:L is 1.08. Lipid content in the whole body decreased, and glycogen concentration in the liver increased with the increase of dietary CHO:L ratios from 0.33 to 3.75 (p < 0.05). Moreover, there was a positive correlation between muscle fatty acid composition and dietary fatty acid composition. The relative expression levels of genes involved in glucose metabolism, such as gk, pepck, and glut2 were upregulated by increasing the dietary CHO:L ratio. Also, the mRNA expression level of genes related to lipid synthesis, such as fas and acc? were significantly upregulated with dietary CHO:L ratios increasing from 0.33 to 3.75. The highest expression of genes involved in fatty acid ?-oxidation, such as cpt1 and acox1, were observed in fish fed the 1.36 CHO:L ratio diet. The gene expression of ?6 fatty acyl desaturase (fads2) in the liver significantly increased with increase of dietary CHO:L ratios from 0.33 to 3.75. Fish fed the diet with CHO:L ratios of 2.26 and 3.75 had lower expression levels of elovl5 than those fed the other diets. These results demonstrate that dietary optimal CHO:L ratios could improve PWG and SGR but also influence expression of genes involved in glucose and lipid metabolism. Based on the overall results, the optimal dietary CHO:L ratio is 1.08 for black seabream.

Project description:The aim of this study was to investigate how dietary arachidonic acid (ARA) level affects growth performance and lipid metabolism in juvenile black seabream (Acanthopagrus schlegelii). A feeding trial was conducted for 8 weeks, during which the fish (0.99 ± 0.10 g) were fed six isonitrogenous and isolipidic diets with varying ARA levels of 0.1%, 0.59%, 1.04%, 1.42%, 1.94%, and 2.42%. Fish fed the diet with 1.42% ARA had significantly higher weight gain (WG) and specific growth rate (SGR) than the other groups (p < 0.05), except for the ARA1.04. As the ARA level increased, the liver and muscle effectively accumulated n-6 polyunsaturated fatty acids (n-6 PUFAs; p < 0.05). However, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and n-3 PUFA contents of liver and muscle significantly decreased by increasing dietary ARA level (p < 0.05). Results of liver histology showed dramatically increased vacuolar fat droplets leading to hepatic fat pathological changes in fish fed diets with ARA levels of 1.94% and 2.42% (p < 0.05). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities increased with increasing dietary ARA level which was accompanied with elevated liver lipid content (p < 0.05). Consistently, triglyceride (TG) and nonesterified fatty acid (NEFA) concentrations of serum and liver, and serum cholesterol (CHO) concentration increased (p < 0.05). As the level of dietary ARA increased, the indicators of lipid metabolism such as sirtuin 1 (sirt1) and peroxisome proliferator-activated receptor α (pparα) also increased (p < 0.05). However, after reaching their peak in ARA1.04 group, the level of these indicators declined (p < 0.05). The same trend was observed for the expression of genes related to the downstream pathways. While the mRNA levels of sterol regulatory element-binding protein-1 (srebp-1) and its downstream genes were markedly increased with the increase of dietary ARA level (p < 0.05). In conclusion, these data suggested that the optimum dietary ARA requirement of A. schlegelii is 1.03% of diet based on the WG. The study revealed that a diet containing 1.04% ARA can activate the expression levels of sirt1 and pparα leading to promoted lipolysis. However, dietary ARA levels of ≥1.42% induced lipid accumulation in the liver, as they suppressed the mRNA levels of sirt1 and pparα, while elevating the expression level of genes related to lipogenesis.

Project description:The fish-gut microbiota play a key role in the physiology, development, and fitness of its host. An understanding of fish-gut microbial communities and the factors influencing community composition is crucial for improving fish performance. In this study, we compared the gut microbiota of juvenile black sea bream Acanthopagrus schlegelii among habitats: (1) wild, (2) offshore cage-culture, and (3) pond-culture. We also explored the relationships between the gut microbiota and host-associated environmental factors. Gut samples and associated environmental compartments were investigated using 16S rRNA gene sequencing. Our results revealed significant habitat-specific differences among the gut microbiota of juvenile A. schlegelii. Wild populations of juvenile A. schlegelii had more diverse gut microbiota than populations cultured in pond habitats due to their omnivorous feeding habits and the corresponding abundance of natural food resources. Significant variations in the composition, core taxa, and diversity of the microbiota were also found between the gut and the environmental compartments. However, no significant differences were observed among the microbiota of the environmental compartments in the relatively isolated pond habitat. Source tracking analysis recovered connections between the fish-gut microbiota and the diet, water and sediment environmental compartments. This connection was especially strong between the microbiota of the fish gut and that of the diet in the pond habitat: the diet microbiota accounted for 33.48 ± 0.21% of the gut microbiota. Results suggested that all A. schlegelii shared a core gut microbiota, regardless of differences in diet and habitat. However, environmental factors associated with both diet and habitat contributed to the significant differences between the gut microbiota of fish living in different habitats. To the authors' knowledge, this study presents the first comparison of gut microbiota among juvenile A. schlegelii with different diets and habitats. These findings enrich our understanding of the gut microbiota of A. schlegelii and help to clarify the interaction between gut microbiota and environmental factors. Our results may also help to guide and improve fish ecological fitness via the regulation of gut microbiota, thereby increasing the efficacy of stock enhancement programs for this species.

Project description:High nutritional value and the development of efficient biotechnological methods of controlled production have made black porgy (Acanthopagrus schlegelii) an economically important fish in Chinese aquaculture in recent years. However, aquaculture production of the species faces multiple issues associated with reduced growth rate, low reproduction ability, and high mortality during production, which are associated with the species' limited tolerance to low temperatures. To date, comprehensive information on the genetic-based mechanisms of cold tolerance and adaptation to low temperature in the species are still unavailable. In this study, the HiSeq™2500 (Illumina) sequencing platform was used to analyze the transcriptomic profile of the liver tissue in the black porgy subjected to different extents of cold shock, including a control temperature group (AS, T = 15 °C), an intermediate temperature group (AL1, T = 10 °C), and an acute low-temperature stress group (AL2, T = 5 °C). For this purpose, three standardized cDNA libraries of AS, AL1, and AL2 were established. We obtained 43,258,908, 48,239,072, and 38,983,833 clean reads from the AS group, AL1 group, and AL2 group, respectively. After pairwise comparison, 70 differentially expressed genes (DEGs) were identified in the examined fish groups. Among them, 60 genes were found to be significantly differentially expressed after trend analysis. GO annotation and enrichment results showed that they were mainly enriched into three categories: biological processes (12 subcategories), molecular functions (7 subcategories), and cellular components (7 subcategories). KEGG analysis results indicated that all significantly differentially expressed genes were annotated to 102 signaling pathways, including biological rhythm, cholesterol metabolism, glycerolipid metabolism, animal autophagy, FoxO signaling pathway, steroid biosynthesis, and regulation of adipocyte lipolysis and apoptosis. Four of them, namely: G6PC, GPX1, GCK, and HSPE1 were randomly selected for further qRT-PCR verification of data reliability obtained by RNA-Seq technology. In this study, we found that environmental acute cold stress mainly affected the black porgy's biological processes related to metabolism, apoptosis, and signal transduction. The data that we have reported provides baseline information for further studies concerning the genetic responses of the black porgy under cold stress conditions, the improvement of its aquaculture production, and other economically important matters regarding their limited tolerance to cold shock.

Dataset Information

The Benefit of Optimal Dietary Lipid Level for Black Seabream Acanthopagrus schlegelii Juveniles under Low-Salinity Environment.

Publications

The Benefit of Optimal Dietary Lipid Level for Black Seabream <i>Acanthopagrus schlegelii</i> Juveniles under Low-Salinity Environment.

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