Abstract
In the White sturgeon fish farms, some individuals have difficulty in getting access to food: such sturgeons are called "runts", and they result in a slower growth rate than normally feeding fish. In this paper, we have studied the gut peculiarities of runt sturgeons. Utilizing in paralleling an analysis of diatom populations in both the fish gut tissues and the rearing tank waters, we hypothesized a causative relation between the occurrence of runt sturgeons and periodic diatom blooms. In fact, we have observed that the diatom species identified in the aquatic environment were also detected in organs (Fragilaria spp and Rhoicosfenia spp for both glandular body, mid-intestine) of the runt sturgeon's gut, but not in tissues of normally feeding individuals. Owing to their siliceous wall, diatoms can be responsible for areas of epithetlial detachment in the mucosal surfaces of the alimentary canal and a catharral inflammation in both the gastric pits and intestinal folds which may be the cause of secondary bacterial diseases. We suggest that diatom blooms may contribute to the occurrence of runt sturgeons in the studied Italian fish farm.
Highlights
When farming white sturgeons (Acipenser transmontanus Richardson, 1836), is unusual within the same stock, some sturgeons have a prolonged difficulty in getting access to food, and become emaciated (feed-deprived sturgeons are called “runts”, Figure 1(a))
We suggest that diatom blooms may contribute to the occurrence of runt sturgeons in the studied Italian fish farm
We previously described in runt sturgeons that some gut structures demonstrate clear alterations [1]
Summary
When farming white sturgeons (Acipenser transmontanus Richardson, 1836), is unusual within the same stock, some sturgeons have a prolonged difficulty in getting access to food, and become emaciated (feed-deprived sturgeons are called “runts”, Figure 1(a)). The runt condition results in a slower growth rate than that of normally feeding fish, as well as slower swimming [2,3], giving rise to the occurrence of growth depensation phenomena in fish tanks. Growth depensation phenomena are not infrequent in fish farms, and may depend on individual size- and food-related factors [4,5]. These factors possibly depend on hierarchical relationships among fish, including competition for food, stocking density, and differences in swimming activity [6,7], as well as on the presence of stressful conditions, surely not infrequent in culturing conditions. In addition to changes affecting the skin and gills, which are directly in contact with the aquatic environment, environmental stressors may influence the structure of the gastrointestinal tract, because its surfaces
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
