Diet-shift driven delta C-13 and delta N-15 changes in liver and muscle tissues of juvenile clownfish Amphiprion frenatus: A laboratory experiment

作者：Schmidt Sandra Nadja; Lund Hansen Lars Chresten; Kristensen Erik^*

来源：Journal of Experimental Marine Biology and Ecology, 2016, 475: 137-143.

DOI：10.1016/j.jembe.2015.11.017

• Isotopic fractionation
• Isotopic enrichment
• Turnover rates
• Aquatic foodwebs

A laboratory-based diet-shift study using juvenile downfish (Amphiprion frenatus) was performed to determine 1) isotopic turnover rates and 2) trophic fractionation of delta C-13 and delta N-13 in liver and muscle tissues. A brood of A. frenatus was first fed shrimps (Acetes elythraeus) with delta C-13 = -19.2 parts per thousand and delta N-13 = 8.3 parts per thousand for 29 days to provide an isotopic baseline. Subsequently, they were fed muscle filets from a predatory reef fish (Sparus latus) with isotopic signature of delta C-13 = -15.9 parts per thousand and delta N-13 = 11.3 parts per thousand. The results showed significant differences in delta C-13 and delta N-15 between liver and muscle throughout the most of the experiment, indicating different incorporation of isotopes by these two tissues. delta C-13 in muscle tissue was less depleted than liver tissue before the diet shift and more depleted after. The change in isotopic composition was significantly faster for liver than muscle tissue after the diet-shift. A hyperbolic saturation model provided a good fit for predicting the time scale of isotopic turnover. The model showed that liver tissue approaches isotopic saturation 3-4 times faster than muscle tissue. Isotopic fractionations extrapolated from the model output at saturation were remarkably similar for liver and muscle tissues (Delta C-13 of -0.5 and -03 parts per thousand, and Delta N-15 of 2.6 and 2.8 parts per thousand, respectively), which indicates that fractionation is independent of tissue or organ in A. frenatus. Liver tissue therefore appears more useful than muscle tissue as a short-term dietary indicator for A. frenatus and possibly also for other fish species.

• 出版日期2016-2