Impacts of low salinity exposure and antibiotic application on gut transport activity in the Pacific spiny dogfish, Squalus acanthias suckleyi

摘要: The role of the marine elasmobranch gastrointestinal tract in nitrogen-recycling and osmotic homeostasis has become increasingly apparent, with gut microbial community likely playing a significant converting urea, an important osmolyte elasmobranchs, into ammonia. Pacific spiny dogfish can experience tolerate reduced environmental salinities, yet how this challenge may affect microbiome, consequently nitrogen transport across gut, is as unknown. In present study, excised sac preparations were made from acclimated to following: full-strength seawater (C), low salinity for 7 days (LS), after acute transfer LS-acclimated fish SW 6 h (AT). Significantly derived urease activity was observed mucosal saline LS (by 81%) AT 89%) treatments relative C treatment. Microbial cellulase samples tended follow similar patterns. To further ensure effective decrease spiral valve population, antibiotic cocktail applied used vitro measurements ion, water, flux these preparations. This caused 57–61% treatments. Overall, we relatively little stomach all measured parameters aside water movement, which switched net efflux control influx acutely transferred fish, indicative drinking. While no differences terms (urea or ammonia), see accumulation ammonia lumen switch urea versus fish. increased production occurs result heightened metabolism challenging environment, while retention acquisition suggestive scavenging under nitrogen-limiting conditions.