The influence of dietary fatty acid composition on the respiratory and cardiovascular physiology of Adriatic sturgeon (Acipenser naccarii): a review

This paper reviews evidence that the fatty acid composition of dietary lipi ds influences the respiratory and cardiovascular physiology of Adriatic stu rgeon (Acipenser naccarii) and, thereby, their tolerance of the stress of h ypoxia. Sturgeon fed a commercial diet enriched in fish oil (menhaden oil a s 15% of dry feed weight), with an elevated content of highly unsaturated f atty acids of the omega 3 series (omega 3 HUFA), had a significantly lower standard metabolic rate (SMR) and routine oxygen consumption (Mo-2) than th ose fed a diet enriched with the same quantity of hydrogenated coconut oil, with an elevated content of saturated fatty acids (SFA). Both groups grew equally well. As a result of this difference in aerobic metabolism, sturgeo n fed the omega 3 HUFA and SFA responded differently when exposed to hypoxi c challenges. Sturgeon fed omega 3 HUFA exhibited no significant reflex hyp erventilation when exposed to mild, moderate or deep hypoxia (30 min at wat er O-2 partial pressures of 10.8, 6.6 and 4.6 kPa, respectively), no hypoxi c depression of spontaneous activity during 3h in mild hypoxia, and no depr ession of Mo, during 3h in moderate hypoxia, unlike sturgeon fed SFA. The d iets also influenced the performance of isolated hearts in vitro. Hearts fr om fish fed omega 3 HUFA maintained maximum in vitro cardiac power output u nchanged when oxygen supply was reduced (O-2 content from 2.3 to 0.7 vol.%) , unlike hearts from sturgeon fed SFA. Overall, the results indicate that d ietary fatty acid composition can influence tolerance of hypoxia in sturgeo n, through effects on SMR. When compared to sturgeon fed SFA, those fed ome ga 3 HUFA had lower SMR and were more tolerant of hypoxia, with effects bot h on the whole animal and on the isolated heart.