Two experiments were conducted with juvenile rainbow trout (Oncorhynchus mykiss) (< 5g) in
ambient well water, to investigate the influence of phytic acid removal on the feeding value of rapeseed and
canola protein feedstuffs used as substitutes for fish meal and other animal protein in the diets.
The first investigation examined whether phytic acid removal by commercial pretreatment of
rapeseed protein concentrate (RPC) with microbial phytase, with /without essential amino acid
supplementation or cation-anion balancing to mimic the chemical profile of a control diet based on fish
meal (which provided 59% of the dietary protein), could improve the nutritional value of RPC for trout
sufficiently to allow it to replace all of the fish meal without compromising performance. Results indicated
that commercial dephytinization significantly enhanced the nutritional value of RPC to the extent that, with
the addition of FINNSTIM™ (1.5 % DMB; palatability enhancer), it could replace all of the fish meal
without compromising performance. Essential amino acid supplementation and cation-anion balancing
provided no additional nutritional benefit.
The second investigation, examined whether commercial dephytinization or dephytinization by oral
administration of a low dose (1,000 PU/ g dry diet) or high dose (4,000 PU/g dry diet) of microbial phytase
to diets in which fish meal provided 70% of the protein and canola meal (CM) provided 20%, or animal
protein-free diets in which RPC provided 95% of the protein, could enhance the nutritional value of the
diets for trout. Also, the effect of fibre reduction of CM with or without the addition of a high dose of
phytase was examined.
Findings indicated that in diets containing 1.5% FINNSTIM™ , commercial dephytinization as
well as direct application of either dose of phytase significantly improved the nutritional value of CM for
trout. By contrast, direct application of either dose of phytase did not improve the nutritional value of RPC
for trout. Although commercial dephytinization did improve RPC nutritional value, the enhancement was
not sufficient to make the diets nutritionally equal to the control fish meal diet. Fibre reduction with or
without direct phytase addition did not nutritionally improve the CM diets to levels comparable to the
control diets.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/9199 |
| Date | 05 1900 |
| Creators | Prendergast, Angela Fay |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
Page generated in 0.0092 seconds