Book of Abstracts
11th IFOAM Scientific Conference
11-15 August 1996, Copenhagen, Denmark
Danish Institute for Fisheries Technology and Aquaculture, Hirthshals, Denmark; 1) Present address: Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan Hubei, 430072, P. R. China
Three experiments were carried out to investigate the effects of the incorporation of potato protein concentrate in the diets for rainbow trout (Oncorhynchus mykiss) on feed intake, digestion, growth, feed utilization and body composition. Experiment 1 and 2 were carried out in duplicate in 10 tanks with recirculated water. The diets for experiment 1 contained 8.3-45.4% PPC and those for experiment 2 contained 2-10% PPC. Experiment 3 was carried out induplicate in 12 conical-bottomed tanks with faecal collectors to measure the feed intake and digestibility. Flowing through water was used in this system.
The results of experiment 1 shows that, at high levels of incorporation (10-45.5%), the growth decreased linearly with increased dietary PPC levels. The relationship between the growth rate and dietary PPC level can be considered as: SGR=3.56-0.107*PPC.
The results of experiment 2 shows that, while the incorporation of PPC levels were more than 2%, the growth decreased significantly with the increased PPC levels. The relationship between growth and dietary PPC level was: SGR=3.59+0.017*PPC-0.015*PPC^2. The feed utilization in both experiment 1 and 2 showed the same trend as the growth, respectively. The results of experiment 3 shows that: the increased incorporation of PPC linearly decreased feed intake (FR=2.53-0.096*PPC). The increased dietary PPC tended to increase the apparent digestibility on dry matter and protein, while there was no effect on fat. Increased dietary PPC also decreased dry matter content and fat content offish body while increase protein content and ash content. 0.5% methionine supplementation decreased food intake, growth and feed utilization. It can be concluded that more than 2% dietary PPC for rainbow trout decrease growth and feed utilization. Extra methionine supplementation is not necessary.
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