Natural Stable Isotopes for Determination of Gastrointestinal Transit Time in Fish

作者：Goncalves de Sandre Lidiane Cristina; Buzollo Hellen; Torres do Nascimento Thiago Matias; Neira Ligia Maria; Abimorad Eduardo Gianini; Jomori Rosangela Kiyoko; Ducatti Carlos; Portella Maria Celia; Carneiro Dalton Jose^*

来源：Journal of the World Aquaculture Society, 2016, 47(1): 113-122.

DOI：10.1111/jwas.12244

This study evaluated the application of stable isotopes of carbon as an alternative and more accurate method to determine gastrointestinal transit time (GTT) in fish by comparing it to the inert marker method. The stable isotope method detects alterations of the normal carbon flow in a biological system by analyzing naturally occurring isotopes of carbon, contrary to studies based on conventional techniques that apply external markers to the diet to determine GTT through visual observation of the color change in feces. Therefore, 320 pacu, Piaractus mesopotamicus juveniles were reared in 32 tanks under two different temperatures (25 and 29 C). The pacu juveniles received two different diets, one based on ingredients derived from C-3 photosynthetic cycle plants and the other based on C-4 plant ingredients, both containing titanium oxide (TiO2) as a marker. After 40 d, the isotopic signature of the diets was changed, and the marker was replaced by chromic oxide (Cr2O3). In the isotopic technique, the feces were analyzed to determine the exchange in the isotopic ratio of carbon C-13. Both methods found that GTT was faster (nearly 6h) in fish at 29 C when using the C-4/C-3 feeding strategy and slower in fish at 25 C using the C-3/C-4 strategy (15h by inert marker and 18h by the isotopic method). In conclusion, GTT determination in pacu juveniles using the stable isotope technique exhibits the same accuracy obtained with the inert marker method at temperatures suitable (nearly 29 C) for the metabolism of these animals.

• 出版日期2016-2