Replacement of Sulfur, Carbon, and Nitrogen in Tissue of Growing Broad Whitefish (Coregonus nasus) in Response to a Change in Diet Traced by δ³⁴S, δ¹³C, and δ¹⁵N

Abstract

We monitored the change in the isotope composition of sulfur, carbon, and nitrogen in broad whitefish (Coregonus nasus) tissues in response to a change in the isotope composition of their food. One of two batches of 2.5-yr-old fish raised in the laboratory were given a new food source with different δ34S, δ13C, and δ15N, which were monitored in muscle and liver tissue for 1 yr. A model including change due to tissue accumulation (growth) and metabolic replacement was developed. For all three isotopes, most of the change could be attributed to growth. Metabolic replacement expressed as a turnover rate was only 0.1 −0.2%∙d−1 and was similar for the three isotopes. Although liver tissue was −4.4 and −4.1‰, respectively, for δ34S and δ13C relative to muscle tissue, the response over time to the new food was the same as for muscle. We expect that the complete change in the isotope composition of fish tissue in response to a change in food could take years in slow-growing wild populations. The stable isotope composition would represent a long-term average of the food. In fast-growing fish the rate of change would directly reflect the growth rate.

Artemia replacement in co-feeding regimes for mysis and postlarval stages of Litopenaeus vannamei: Nutritional contribution of inert diets to tissue growth as indicated by natural carbon stable isotopes

“…After the experimental dietary treatments were differentiated, shifts in δ 13 C values of shrimp fed on the different feeding regimes (except those fed on inert diet) stabilized quickly in the mysis and postlarval stages. Rapid isotopic changes are due to both, high growth and metabolic turnover rates, in the present study indicated by parameters from the exponential model (Hesslein et al, 1993). Fry and Arnold (1982) also observed fast δ 13 C turnover in P. aztecus shrimp postlarvae fed Artemia, which led to short carbon metabolic half time in tissue (4 d).…”

“…In order to obtain an estimate of the metabolic carbon turnover rate, changes in δ 13 C values in shrimp following a dietary shift from C. gracilis to the different experimental feeding regimes were fitted to the following exponential model (Hesslein et al, 1993) in order to integrate growth and isotope value shift over time:…”

Nutritional contribution of torula yeast and fish meal to the growth of shrimp Litopenaeus vannamei as indicated by natural nitrogen stable isotopes

“…Total dry matter contributions were estimated after correcting for nitrogen concentrations measured in both ingredients using the equation proposed by Fry (2006). δ 15 N values measured through the experimental period were integrated in an exponential model of isotopic change (Hesslein et al, 1993) to obtain an estimate of the metabolic nitrogen turnover rate in shrimp muscle tissue. The model allows distinguishing the isotopic change that is due to growth (k) or metabolic turnover (m).…”

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

“…The use of stable carbon and nitrogen isotope ratios (expressed as d 13 C and d 15 N, respectively) in studies of fish diets and lake food-web structure is based on the distinct d 13 C values of pelagic and littoral primary producers and on the trophic enrichment of d 15 N by around 3-4& per trophic level . The d 13 C and d 15 N values from fish muscle tissue typically reflect the diet assimilated over a few months (Hesslein, Hallard & Ramlal, 1993;. Hence, isotopic studies of fish trophic ecology are not subject to the same potential sampling errors as SCA, such as temporal changes in availability, patchy distribution and different digestion times of prey items Boecklen et al, 2011).…”

“…The observed partial reliance of pelagic-caught planktivorous charr on littoral carbon sources may reflect general niche plasticity and ⁄ or consumption of pleuston originating from the littoral or profundal zone that has a higher d 13 C value than the predominant zooplankton diet. Because of the long turnover time of muscle tissue (Hesslein et al, 1993;, the isotopic composition of pelagic-caught charr may also partly reflect their spring-time diet, which is likely to have been dominated by littoral zoobenthos at a time when zooplankton is extremely sparse in these lakes .…”