Effects of soybean meal and high protein sunflower meal on growth performance, feed utilization, gut health and gene expression in artic charr (Salvelinus alpinus) at the grow-out stage

Authors: SMITH, AMANDA - University Of Guelph; DUMAS, ANDRE - Coastal Zones Research Institute Inc; YOSSA, RODRIGUE - Coastal Zones Research Institute Inc; Overturf, Kenneth - Ken; BUREAU, DOMINIQUE - University Of Guelph

Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2018
Publication Date: 3/30/2018
Citation: Smith, A.A., Dumas, A., Yossa, R., Overturf, K.E., Bureau, D.P. 2018. Effects of soybean meal and high protein sunflower meal on growth performance, feed utilization, gut health and gene expression in artic charr (Salvelinus alpinus) at the grow-out stage. Aquaculture Nutrition. https://doi.org/10.1111/anu.12691.
DOI: https://doi.org/10.1111/anu.12691

Interpretive Summary: Interpretive Summary Fishmeal has become more expensive and as a consequence is being reduced in aquaculture feeds. As histological and molecular analysis have shown, the use of feeds high in plant protein can have bad effects in fish and may even increase mortality. The main problem in rearing fish on feeds formulated with alternative proteins is that the precise nutrient requirement for different species is unknown as are the physiological effect of plant protein products. In this experiment fishmeal was replaced with two different plant proteins, either soybean or sunflower meal, and fed to arctic char. The effects of the ingredients were evaluated by monitoring fish growth, effects on intestinal health, and expression of immune factors. After the 12 week feeding trial no changes in growth were observed between the two diets, but intestinal damage occurred in fish fed soybean meal feed. Thus, sunflower meal can replace up to 25% of the fishmeal in char feed and does not cause the problems observed with soybean meal feed.

Technical Abstract: Effects of soybean meal and high protein sunflower meal on growth performance, feed utilization, gut health and gene expression in arctic charr (Salvelinus alpinus) at the grow-out stage Technical Abstract The effects of two plant ingredients [solvent-extracted soybean meal (SBM) and high protein sunflower meal (HPSFM)] and three inclusion levels (0%, practical diet containing 25% fish meal; 12.5%; and 25%) of these ingredients were investigated on the growth, feed utilization, gut histology and pro-inflammatory gene expression in the distal intestine of Arctic charr Salvelinus alpinus. Feeding experimental diets with increasing inclusion of SBM or HPSFM for 12 weeks resulted in no difference between SBM or HPSFM diets in body weight gain, growth rate, feed efficiency, feed intake, or pro-inflammatory mRNA expression with increasing dietary inclusion. Significant differences in quadratic contrasts for nitrogen deposition rate (NDR) and nitrogen retention efficiency (NRE, % intake) were observed, whereby HPSFM diets elicited the strongest positive response. Histological measurements of distal intestine simple fold lengths and widths revealed significantly linear differences between SBM- and HPSFM-fed fish. SBM resulted in notable reduction in both measurements with step-wise increases in dietary inclusion, and dietary HPSFM had no effect. Additionally, histological observations of individual villi indicate several, however not all classical symptoms of non-infectious subacute gastrointestinal enteritis in tanks fed SBM, many of which were not present in tanks fed HPSFM. The dietary HPSFM seems to be more adequate to replace fishmeal in Arctic charr diet than SBM, when fed at a level of up to 25% at the grow-out stage.