期刊名称：Western Australia. Fisheries Department. Fisheries Research Reports
印刷版ISSN：1035-4549
出版年度：2008
卷号：178
页码：268-268
出版社：Government of Western Australia / Department of Fisheries
摘要：A series of studies were undertaken to examine the effect of drying processes on the
composition, digestibility and utilisation efficiencies of different types of lupin (L. angustifolius
cv. Myallie) protein concentrates when fed to rainbow trout. Three different LPC drying
methods (freeze-drying: FD, spray-drying: SD, and heat-drying: HD) were studied. Significant
effects of drying process were observed on the composition of the LPC; most notable was the
relative increase in the level of crude fibre and decrease in crude protein with the heat-dried
product. The digestibilities of each of the LPC were assessed using the diet-substitution method
with faecal collection undertaken using stripping techniques. No significant differences in the
digestibilities of protein or energy, or total digestible protein and energy concentrations were
observed among the LPC. To assess the utilisation of protein and energy, fish were fed diets
with a 300 g/kg inclusion level of either the spray-dried or heat-dried LPC. A third fishmeal
based reference diet was also used. The diets were formulated to equivalent digestible protein
and energy specifications based on predetermined digestibility values. Each of the diets was
fed at one of three ration levels and an additional starved treatment was also included. In a 28-
day growth study, fish of 96.4 ± 1.7 g (mean ± S.D.) kept in freshwater at 13.9 ± 0.2°C grew
in accordance with their ration level, but with some significant differences observed among
the diets. This experiment shows that the dietary inclusion of the heat-dried LPC significantly
reduced the efficiency of energy gain. Utilisation of digestible protein at lower digestible protein
intake levels did not appear less efficient with the heat-dried LPC, but at higher protein intake
levels it was not as efficiently used as spray-dried LPC or fishmeal protein. A greater proportion
of the nitrogen excretion from the fish fed the heat-dried LPC diet was observed as urea. This
study demonstrates that the drying regime used on a processed grain product may not affect the
ability of fish to digest the protein and energy from that grain product, but may affect the ability
of the fish to utilise the dietary digestible protein and energy of the ingredient.
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