Edison Rodrigo Serrano Gutiérrez defended his thesis on April 27th 2011

Ane Gro Siri Skjelfjord

Biological responses in rainbow trout (Oncorhynchus mykiss) after dietary intake of lupine seeds and quinolizidine alkaloids

Abstract from the thesis - PhD thesis 2011:18

The use of lupins as protein source in salmonid diets is limited by the presence of quinolizidine alkaloids, the main ones being lupinine and sparteine. The aim of these studies was to examine the effect of high dietary inclusion of white lupine (Lupinus albus) and the effect of dietary inclusion of lupinine and sparteine on growth, feeding parameters and tissue histology in rainbow trout (Oncorhynchus mykiss), and to determine their tolerance and acute toxicity concentration.

In a first experiment, juvenile rainbow trout were fed extruded diets containing high levels of whole white lupine seeds (30, 40 and 50%) for 84 days. Regardless the lupine inclusion levels, fish fed diets containing this ingredient showed growth rates, feed conversion ratios and survival similar to those fed the control diet (LT fishmeal based diet). Furthermore, the inclusion of whole white lupine seeds did not significantly affect (P> 0.05) the whole body proximate composition, the liver and intestinal histology or the nutrient digestibilities. The muscle fatty acid profile and hepato-somatic index were, however, slightly affected (P<0.05) by dietary inclusion levels higher than 30% lupine in the feed.

In the two subsequent experiments, dose-response studies with lupinine and sparteine were performed in rainbow trout. Fish were fed extruded fishmeal based diets containing 0, 50, 75, 100, 250, 500, 1,000 and 5,000 mg lupinine kg-1 and 0, 50, 100, 250, 500, 1,000, 2,500 and 5,000 mg sparteine kg-1, for 60 and 62 days, respectively. Feed intake and growth were reduced in response to increasing dietary dose of lupinine and sparteine alkaloids, and the dose response was best fit to a quadratic dose-response curve. Tolerance levels of lupinine and sparteine with regard to growth and feed intake was up to 100 mg kg-1 feed. Carcass composition did not vary among treatments. Depletion of glycogen and lipid stores in the hepatocytes was observed at high levels of both lupinine and sparteine, however, this was most likely related to very low feed intake. No morphological changes were observed in kidney, heart, spleen or intestinal tissue.

These results show that both lupinine and sparteine possess a strong anti-palatability effect that consequently reduces feed intake, growth and feed utilization at high levels. However, these alkaloids did not seem to cause adverse short-term risk to the health of rainbow trout. Therefore, high inclusions of lupine varieties containing less than 200 mg alkaloids kg-1 will not affect the palatability of the feed or cause any health impairment. These findings will allow plant breeders to produce lupins for use in fish feeds, containing 10 folds more quinolizidine alkaloids than the current agronomically costly sweet lupin varieties that are mostly grown.

Updated: 10.06.11
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