title: Effects of feed restriction on salinity tolerance in white sturgeon (Acipenser transmontanus).
abstract: A multistressor study was conducted to investigate interactive effects of nutritional status and salinity on osmoregulation of juvenile white sturgeon. Our hypothesis was that lower nutritional status would decrease the salinity tolerance of juvenile white sturgeon. A four-week feed restriction (12.5%, 25%, 50%, 100% of optimum feeding rate: OFR defined as the rate (% body weight per day) at which growth is maximal) trial was performed, and relevant indices of nutritional status were measured. Following the trial, sturgeon were acutely exposed to various salinities (0, 8, 16, 24 ppt) for 120 h, and relevant osmoregulatory measurements were made at 12, 72, and 120 h post-salinity exposures. The feed-restriction trial resulted in a graded nutritional response with the most feed-restricted group (12.5% OFR) showing the lowest nutritional status. The salinity exposure trial showed clear evidence that lower nutritional status decreased the salinity tolerance of juvenile white sturgeon. Increasing salinities resulted in significant alterations in osmoregulatory indices of all feeding groups; however, a significantly slower acclimatory response to 24 ppt was detected in the most feed-restricted group compared to the non-feed-restricted group (100% OFR). Furthermore, evaluation of the effect of nutritional status on the relationship between osmoregulatory measurements and body size showed that there was a significant negative relationship between osmoregulatory performance and body size within the most feed-restricted group. This suggests that there is a certain body size range (200-300 g based on our finding) where juvenile white sturgeon can maximize osmoregulatory capacity at a salinity of 24 ppt.
authors.affiliation: Department of Animal Science, University of California, Davis, CA 95616, USA.
authors.forename: Seunghyung
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Animal Science, University of California, Davis, CA 95616, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Fadel
authors.affiliation: Department of Animal Science, University of California, Davis, CA 95616, USA.
authors.forename: Liran Y
authors.initials: LY
authors.lastname: Haller
authors.affiliation: Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Verhille
authors.affiliation: Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA.
authors.forename: Nann A
authors.initials: NA
authors.lastname: Fangue
authors.affiliation: Department of Animal Science, University of California, Davis, CA 95616, USA. Electronic address: sshung@ucdavis.edu.
authors.forename: Silas S O
authors.initials: SS
authors.lastname: Hung
mesh_terms: D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology; D000818:Animals; D049628:Body Size / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D005399:Fishes / Q000502:physiology*; D064587:Osmoregulation / Q000502:physiology; D054712:Salinity; D055049:Salt Tolerance / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D013997:Time Factors; D014882:Water-Electrolyte Balance / Q000502:physiology
keywords: Climate change; Food web alteration; Nutritional status; Osmoregulation; San Francisco Bay-Delta