Meeting Abstract
Although they carry cellulase-producing bacteria in the digestive tract, crayfish (Astacoidea and Parastacoidea superfamily) also produce endogenous, enzymatically active cellulase (glycosyl hydrolase family 9, GHF9) in the digestive gland of the hepatopancreas. Crayfish are omnivores but prefer food of plant origin. Therefore, we tested here the effect of strict plant-based feeding on the distribution of cellulase-producing bacteria in the gut microbiota of Rusty Crayfish (Faxonius rusticus), which is an invasive species that has expanded its niche from Ohio River basin to twenty-seven states including the state of Oregon, the west side of the Continental Divide. Prior to beginning feeding trials, excrements were collected from housing vessels for microbial composition analysis. After three weeks of feeding regimens, that included plant- or protein-based diets, excrements were again collected from housing vessels. The microbial composition of feces was subsequently analyzed by culturing, followed by biochemical assays. Our data showed that the proportion of cellulase-producing bacteria was significantly increased in both cohorts, yet the rate of the increase was much higher in the group of the plant-based feeding. Interestingly, the population of gram-negative bacteria was significantly reduced in both groups, indicating that the majority of the cellulase producers were gram-positive bacteria. The identification of the cellulase producing microorganisms is currently under investigation using 16s rRNA gene amplicon sequencing.
