Güthler, Karen: Studies of phosphorus requirements in gilthead seabream (Sparus aurata) and of potential use of supplementary phytase in gilthead seabream and rainbow trout (Oncorhynchus mykiss). - Bonn, 2005. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5N-06414
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5N-06414,
author = {{Karen Güthler}},
title = {Studies of phosphorus requirements in gilthead seabream (Sparus aurata) and of potential use of supplementary phytase in gilthead seabream and rainbow trout (Oncorhynchus mykiss)},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2005,
note = {The aim of this study was to test plant feedstuffs as an alternative to fishmeal in diets for rainbow trout and gilthead seabream, focussed on the reduction of phosphorus excretion and the potential use of microbial phytase. The trout experiments took place in Germany in the Institute of Animal Nutrition of the University of Bonn. The seabream experiments were carried out in the National Center for Mariculture in Eilat, Israel. In all experiments digestibility and/or utilisation of phosphorus was determined by the difference method.
In two growth experiments response of seabream to rising levels of dietary phosphorus was examined. Each trial contained seven diets basing on wheat gluten. Different levels of dietary phosphorus at constant remaining composition were achieved by supplementation of di-calcium phosphate (DiCaP) in the first and mono-calcium phosphate (MoCaP) in the second experiment. In separated experiments the digestibilities of DiCaP and MoCaP were determined in seabream.
In a third growth experiment the effect of rising supplementations of microbial phytase was examined. This experiment was carried out in parallel in trout and seabream using the same diets which based on soy protein concentrate.
Weight gain, feed intake, feed conversion efficiency and body composition showed a clear dependence on phosphorus or phytase level at phosphorus deficiency. Exceeding respective dietary phosphorus or phytase concentrations showed no further effects. Phosphorus require-ment of seabream was determined to about 6.5 g digestible phosphorus per kg diet at 18 MJ DE/kg. A supplementation of microbial phytase of 1000 FTU/kg was sufficient to enable maximum weight gain in trout. In seabream the requirement of supplemental phytase could not definitely determined, since overall dietary phosphorus concentration was too low for the demand of gilthead seabream.
Additionally several plant feedstuffs were tested for their phosphorus digestibility with and with-out supplementary phytase: full-fat soybeans, soy protein concentrate and rapeseed oilmeal in trout and rapeseed oilmeal in seabream.
The trout diets based on wheat gluten. Test components were added achieving a dietary phosphorus level below the requirement of trout. In the seabream experiment rapeseed oilmeal was the only phosphorus source.
Phosphorus digestibility of rapeseed oilmeal, soy protein concentrate and soybeans in trout could be increased by supplementation of phytase from 27 to 83 %, from 41 to 93 %, and from 43 to 94 % respectively. In seabream phosphorus digestibility of rapeseed oilmeal was improved from 50 to 84 %.},

url = {http://hdl.handle.net/20.500.11811/2203}

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