Authors : Kenan Engin, Hatice A. Yilmaz, I. Ozsahinoglu and P. Mumogullarinda
Abstract: This study investigated the effects of total fish oil replacement by cotton seed and/or canola oils on daily total ammonia and urea-nitrogen excretion rates in the juvenile European sea bass. Iso-nitrogenous and iso-energetic diets formulated to totally replace Fish Oil (FO100) by Cotton Seed Oil (CSO100), Canola Oil (CO100) and equal combination (CSO50/CO50) of these Vegetable Oils (VOs) were fed to fish to apparent satiation and daily fluctuation of Total Ammonia Nitrogen (TAN) and urea-N were measured after 24 h. There was a delay in times of the occurrence of peak excretions in fish fed diets containing VOs. Daily TAN excretion rates decreased whereas daily urea-N excretion increased with the inclusion of VOs in diets and this was particularly the case in fish fed dietary treatment CSO50/CO50 as daily urea-N excretion expressed as percentage of Consumed Nitrogen (CN) was significantly (p<0.05) higher than that of fish fed FO100 diet. There was no significant difference in the theoretically calculated Retained-N + Fecal-N values among the treatments. This study indicated that European sea bass utilized both VOs effectively as an energy source but altered dietary n-3/n-6 ratio seemed to play a part in the nitrogenous excretion mechanism in the European sea bass.
Kenan Engin, Hatice A. Yilmaz, I. Ozsahinoglu and P. Mumogullarinda, 2012. Diurnal Ammonia and Urea Excretion Rates in the Juvenile European Sea Bass, Dicentrarchus labrax Fed Diets Containing Cotton Seed and/or Canola Oils. Journal of Animal and Veterinary Advances, 11: 2220-2229.