Starvation Affects the Muscular Morphology, Antioxidant Enzyme Activity, Expression of Lipid Metabolism-Related Genes, and Transcriptomic Profile of Javelin Goby (Synechogobius hasta)

Abstract

Fish in natural and cultivated environments can be challenged by starvation. However, inducing starvation in a controlled manner cannot only reduce feed consumption but also reduces aquatic eutrophication and even improves farmed fish quality. This study investigated the effects of starvation on the muscular function, morphology, and regulatory signaling in javelin goby (Synechogobius hasta) by evaluating the biochemical, histological, antioxidant, and transcriptional changes in the musculature of S. hasta subjected to 3, 7, and 14 days fasting. The muscle glycogen and triglyceride levels in S. hasta were gradually reduced under starvation, reaching their lowest at the end of the trial ( P < 0.05 ). The levels of glutathione and superoxide dismutase were significantly elevated after 3–7 days of starvation ( P < 0.05 ), but later returned to the level of the control group. The muscle of starved S. hasta developed structural abnormalities in some areas after 7 days of food deprivation, and more vacuolation and more atrophic myofibers were observed in 14-day fasted fish. The transcript levels of stearoyl-CoA desaturase 1 (scd1), the key gene involved in the biosynthesis of monounsaturated fatty acids, were markedly lower in the groups starved for 7 or more days ( P < 0.05 ). However, the relative expressions of genes associated with lipolysis were decreased in the fasting experiment ( P < 0 .05). Similar declines in the transcriptional response to starvation were found in muscle fatp1 and ppar γ abundance ( P < 0.05 ). Furthermore, the de novo transcriptome of muscle tissue from the control, 3-day and 14-day starved S. hasta generated 79,255 unigenes. The numbers of differentially expressed genes (DEGs) identified by pairwise comparisons among three groups were 3276, 7354, and 542, respectively. The enrichment analysis revealed that the DEGs were primarily involved in metabolism-related pathways, including ribosome, TCA pathway, and pyruvate metabolism. Moreover, the qRT-PCR results of 12 DEGs validated the expression trends observed in the RNA-seq data. Taken together, these findings demonstrated the specific phenotypical and molecular responses of muscular function and morphology in starved S. hasta, which may offer preliminary reference data for optimizing operational strategies incorporating fasting/refeeding cycles in aquaculture.

Comparative Analysis of Hepatopancreas RNA-Seq of Juvenile Grass Carp (Ctenopharyngodon idella) Fed Different Starch Diets

“…Total RNAs of hepatopancreas samples (3 treatments × 3 samples, mixture of 6 fish as one sample) were extracted using an RNAprep Pure Tissue Kit (TIANGEN, Beijing, China) according to the manufacturer's instructions. The RNA integrity was determined with 1.5% agarose gel electrophoresis, and the 28S/18S ratio, RNA concentration, and RNA Integrity Number (RIN) were determined using an Agilent 2100 Bioanalyzer (Agilent, Santa Clara, CA, USA) [26]. High purity samples with RIN values more than 8.0 were selected for further analysis as previously described [26].…”

“…The RNA integrity was determined with 1.5% agarose gel electrophoresis, and the 28S/18S ratio, RNA concentration, and RNA Integrity Number (RIN) were determined using an Agilent 2100 Bioanalyzer (Agilent, Santa Clara, CA, USA) [26]. High purity samples with RIN values more than 8.0 were selected for further analysis as previously described [26]. The cDNA libraries were constructed for the CO, WH, and PO groups with three biological replicates, and digital gene expression profiling (DGE) were conducted using BGISEQ-500 platform (BGI, Wuhan, China).…”

“…Jiang [62] has confirmed that high glucose levels repress AMPK signaling pathway via MG53 E3 ubiquitin ligase-induced AMPK degradation and inactivation. When AMPK is inhibited, the expression of SREBP-1c and its downstream genes [26,31,63,64], such as fasn, acc1, elovl6, and scd1, are up-regulated, thus increasing the accumulation of lipid droplets. High dietary levels of digestible carbohydrate induced lipogenesis and enhanced lipid deposition in the liver of rainbow trout (Oncorhynchus mykiss) [12,65,66].…”

Effects of Prolonged Fasting and Refeeding on Metabolic, Physiological, Tissue, and Growth Performance Adjustments in Colossoma macropomum

“…In addition, histological evaluations, such as the influence of fasting on intestinal villi [14] and musculature [15], have also been used as a key method since the digestive tract is directly related to the behavioral characteristics and nutritional status of the fish [16], and the skeletal muscle tissue is the main part of the fish trunk, representing 40 to 60% of its body weight [17,18], and an important source of animal protein for human consumption [18]. Certain fasting situations can lead to substantial decreases in muscle fiber size in many fish species, such as Oreochromis niloticus [19], Ctenopharyngodon idellus [18], and Synechogobius hasta [20].…”