Effect of starvation on intestinal morphology, digestive enzyme activity and expression of lipid metabolism-related genes in javelin goby (Synechogobius hasta)

To assess the effects of starvation on Synechogobius hasta intestinal function and morphology, fish were starved for 3, 7 and 14 days, followed by the measurement of histological, physiological and transcriptional responses in the intestine. Intestinal length was significantly lower in S. hasta starved for 7 and 14 days (p < 0.05). Intestinal amylase activity was significantly decreased upon fasting (p < 0.05), whereas a lower level of intestinal lipase activity was not observed until the end of the trial. After 7-day starvation, the intestine of starved S. hasta exhibited exfoliated villus cells, increased vacuoles and widened cell interstices. Regarding the expression of lipid metabolism-associated genes, poststarvation transcript levels of lipoprotein lipase, carnitine palmitoyltransferase 1 a and fatty acid transport protein 1 significantly increased with longer food deprivation periods (p < 0.05). Meanwhile, downregulation of stearoyl-CoA desaturase 1 was observed in the intestine upon starvation (p < 0.05). In summary, prolonged starvation (>14 days) not only disrupted the intestinal structure, which may further weaken digestive potential, but also attenuated intestinal lipid deposition by diminishing lipid biosynthesis, as well as upregulating lipolysis and fatty acid transport. Therefore, our findings provide preliminary data for further characterization of metabolic traits in starved S. hasta, which may have important implications for determining the appropriate starvation time applied in fasting/re-feeding regimes, as well as the sustainable development of S. hasta and other fish.

Automated summary

Starvation significantly affects the intestinal structure and function of Synechogobius hasta, leading to decreased intestinal length, reduced enzyme activity, and altered intestinal cell structure. The expression levels of lipid metabolism-associated genes increase post-starvation, while some genes are downregulated in the intestine. Prolonged starvation disrupts the intestinal structure, weakens lipid deposition, and affects lipid metabolism.