N-15: an Indicator of the Assimilation of Dietary Proteins for Oreochromis niloticus

作者：Slawski Hanno^*; Goetz Klaus Peter; Schulz Carsten

来源：Israeli Journal of Aquaculture – Bamidgeh, 2010, 62(3): 146-154.

• dietary markers
• stable isotope
• N-15 ammonia
• nitrogen assimilation

The potential of enriched stable isotopes (N-15) for protein digestion and assimilation studies in juvenile fish was evaluated. Fishmeal and maggot meal were enriched with N-15, incorporated into two diets (crude protein 30.2%). Four groups of ten Oreochromis niloticus (47.5 +/- 8.3 g) were fed an experimental diet at the same starting time. After 15 min, 2 h, 4 h, and 6 h, five fish were selected, the stomach and gut were extracted, and the liver, kidney, gills, and musculus lateralis magnus were sampled. Concentrations of N-15 in the stomach 2-6 h after feeding indicate that fishmeal passed through the stomach faster than maggot meal. Differences in digestive tract passage between protein sources were probably due to the hard digestible chitin present in the maggot meal. In the liver, kidney, gills, and musculus lateralis magnus, N-15 in fishmeal and maggot meal nitrogen was assimilated at similar speeds. Results indicate that N-15 can provide comprehensive information about protein digestion and assimilation in fish nutrition studies.

• 出版日期2010