Thiamine and Fatty Acid Content of Lake Michigan Chinook Salmon

Abstract

Nutritional status of Lake Michigan Chinook salmon (Oncorhynchus tshawytscha) is inadequately documented. An investigation was conducted to determine muscle and liver thiamine content and whole body fatty acid composition in small, medium and large Chinook salmon. Muscle and liver thiamine concentrations were highest in small salmon, and tended to decrease with increasing fish size. Muscle thiamine was higher in fall than spring in large salmon. The high percentage of Chinook salmon (24-32% in fall and 58-71% in spring) with muscle thiamine concentration below 500 pmol/g, which has been associated with loss of equilibrium and death in other Great Lake salmonines, suggest that Chinook appear to rely less on thiamine than other Great Lakes species for which such low concentrations would be associated with thiamine deficiency (Brown et al. 2005b). A positive correlation was observed between liver total thiamine and percent liver lipids (r = 0.53, P < 0.0001, n = 119). In medium and large salmon, liver lipids were observed to be low in fish with less than 4,000 pmol/g liver total thiamine. In individuals with greater than 4,000 pmol/g liver thiamine, liver lipid increased with thiamine concentration. Individual fatty acids declined between fall and spring. Essential omega-3 fatty acids appear to be conserved as lipid content declined. Arachidonic acid (C20:4n6), an essential omega-6 fatty acid was not different between fall and spring, although the sum of omega-6 (Sw6) fatty acids declined over winter. Elevated concentrations of saturated fatty acids (sum) were observed in whole body tissue lipid. In summary, thiamine, a dietary essential vitamin, and individual fatty acids were found to vary in Lake Michigan Chinook salmon by fish size and season of the year. INDEX WORDS:Early mortality syndrome, fatty acids, energy metabolism, nutrient deficiency, season.

Maternal influences on thiamine status of walleye Sander vitreus ova

“…The liver is the site of many energetically expensive processes and thus has a high requirement for thiamine. In those cases of suspected thiamine shortage in salmonines, it has been suggested that the muscle to liver thiamine ratio is reduced, indicating preferential retention of the vitamin in liver (Honeyfield et al , 2008). In this context, liver thiamine levels were investigated in one Lake Ontario spawning population, that of the Napanee River.…”

Ontogenetic Dietary Changes and Thiamine Status of Lake Ontario Chinook Salmon, 2005–2006

“…The resulting mean thiamine (nmol) content for the eight size-classes (e.g., 200-1,000 mm) was related to the size-class midpoint (mm), and the resulting variation was examined as above. This procedure assumed that (1) muscle thiamine represented the mean thiamine concentration for the entire body given that muscle comprises the bulk of total body weight, and (2) while other tissues, like liver, have a higher thiamine concentration than muscle (Honeyfield et al 2008a), they represent a relatively small proportion of total body weight (Thorarisson et al 1994). This procedure also assumed that muscle as a proportion of total body weight remained unchanged over the same length categories examined.…”

“…Changes in the thiamine content of adult Chinook Salmon related to size have been documented for Lake Michigan, although the relationship with diet and thiamine dynamics in juveniles remains unclear. For adult Chinook Salmon in Lake Michigan, a negative association was reported between dorsal muscle thiamine concentration and fish size (Honeyfield et al 2008a); thiamine levels in small Chinook Salmon (<490 mm) were almost twofold higher than those in large individuals (>700 mm). Honeyfield et al (2008a) contended that the most likely reason for the differential in muscle thiamine concentrations between small and large fish was that smaller fish were eating a more diverse diet, but no data were provided to support this claim.…”

“…For adult Chinook Salmon in Lake Michigan, a negative association was reported between dorsal muscle thiamine concentration and fish size (Honeyfield et al 2008a); thiamine levels in small Chinook Salmon (<490 mm) were almost twofold higher than those in large individuals (>700 mm). Honeyfield et al (2008a) contended that the most likely reason for the differential in muscle thiamine concentrations between small and large fish was that smaller fish were eating a more diverse diet, but no data were provided to support this claim. The potential for depression of tissue thiamine levels in Chinook Salmon resulting from Alewife consumption may be greater in Lake Ontario, as Chinook Salmon diets in Lake Ontario are reported to contain a greater proportion of Alewives than Chinook Salmon diets in Lake Michigan (Jude et al 1987;Rand and Stewart 1998;Lantry 2001).…”

“…Within the Great Lakes, much of the information concerning the effects of thiamine deficiency on Chinook Salmon is life stage specific, relating primarily to eggs (Marcquenski and Brown 1997;Wolgamood et al 2005;Fitzsimons et al 2007;Ketola et al 2009) or adults (Brown et al 2005b;Honeyfield et al 2008a). It has been shown that Lake Ontario Lake Trout have a decrease in muscle thiamine with increasing size that is directly related to the proportion of Alewives in the diet (J. D. Fitzsimons, unpublished data), but there is relatively little information on juvenile Chinook Salmon that could be used to evaluate the ontogeny of thiamine deficiency, its relationship to consumption of Alewives, and potential negative effects.…”