Transfer to seawater represents a stressful event for salmon smolts and can negatively impact their feeding behavior. A trial in Norway evaluated a sensory feed additive called Optifeed® Aqua designed to improve feed intake in salmon smolts after transfer to seawater. Results showed that smolts receiving the additive consumed 33% more feed over six weeks compared to the control diet, with differences in intake appearing around 10 days after transfer. The additive helped optimize feed intake and appetite after the stressful event of seawater transfer.

1. January | February 2010
Feature title: Preventing the impact of seawater transfer on feed intake in salmon
International Aquafeed is published five times a year by Perendale Publishers Ltd of the United Kingdom.
All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies,
the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of
information published.
©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form
or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058
The International magazine for the aquaculture feed industry

2. F: Nutrition F: Nutrition
we can add a Other feed additives have also been
good sensory shown to increase feed intake during trans-
memory, since fer to seawater. But, when compared to
salmons smolts Optifeed® Aqua, which is essentially com-
Preventing the impact of have the abil-
ity to ‘record’
the smells of
posed of sensorial feed additives (botanicals
and aromatic molecules); most appetite
stimulants studied in fish have been of
seawater transfer on feed
a river along marine origin.
their migration Compared to existing alternatives,
towards the sea therefore, Optifeed® Aqua can be considered
intake in salmon
in order to find as a favourable factor for a sustainable
their way back, aquaculture.
sometimes
years later. Reference
Figure 1: Daily cumulated feed intake (g/tank)
The importance of sensory stimulation in fish feeding
Based on
Stradmeyer L., 1994. Survival, growth and
an expertise of feeding of Atlantic salmon, Salmo salar L.,
sensory stimu-
Improved feed intake lations in fish, a range of feed additive has
smolts after transfer to seawater in relation
to the failed smolt syndrome. Aquacult. Fish.
after smolts transfer been developed specifically to encourage Manage. 25: 103-112.
by Virginie Noirot, Laboratoires Phodé, Albi, France At the end of the six week period, the feed consumption in aquatic species, with a
smolts that received Optifeed® Aqua had specific formula for salmonids /carnivorous
consumed significantly more feed than fishes, and shrimps: Optifeed® Aqua. This
C
with the control diet (487g/tank vs. 366,
hanges in diet, environ- additive, designed to improve feed intake matic feeders (one meal every 15 minutes),
P=0.006).
additive combines three activities: About Phodé
ment or physiology rep- and induce feed loyalty in fish (Optifeed® during six weeks following the seawater Attraction: fishes and crustaceans Phodé is born from the conviction
The cumulated feed intake per tank are particularly attracted to amino acids
resent many stress factors Aqua), has recently been evaluated in transfer. The daily feeding was continuously that the sense of smell is our pri-
over the six-week trial was improved by 33 (L-isomers). Optifeed® Aqua for salmon and
for farmed animals that Norway for its capacity to optimise appetite adjusted according to feed intake the previ- mary sense, and one of the driving forces
percent with Optifeed® Aqua. carnivorous fish contains a formulation of
can impact their appetite, health and and feed intake following the transfer of ous two days, aiming at an overfeeding of 20 behind the behavior and well-being of
The difference between treatments amino acids composed of two blends: one
performance. In salmon farming, the Atlantic Salmon smolts into seawater. percent to allow optimal feed intake. living beings. Its mission is to capitalise
started to appear around 10 days after the present in a plant and an other in a seawa-
transfer of smolts from freshwater to It showed an interesting potential for a Feed waste were collected from the out- on its expertise of olfaction and nutrition
beginning of the experiment (see Figure 1). ter animal, both being particularly attractive
seawater is a stressful event. profitable and sustainable aquaculture. let and dried in order to quantify feed intake. to improve the well-being and health
The water average temperature was for these types of fish. of humans and animals, both through
The effects of sensory
Stradmeyer (1994) has shown that the Trial conditions 8.7°C, salinity 33ppt. The fishes were
stimulation in fish
Appetite stimulation: a specific core their food and their environment. Phodé
weeks following this transfer see a dra- A production trial was conducted in weighted individually at start and at the end based on plant extracts has been developed develops, produces and distributes
As mentioned earlier, transfer to sea- to stimulate the appetite center and path-
matic drop of appetite and feed intake: in his Norway at the Nofima Marine experimental of the trial. innovative solutions for animal nutrition,
water represents a stressful event and can way within the nervous system.
observations, only 10 percent of the fishes station, SunndalsØra, and supervised by AVS the environment and the food industry
have a detrimental effect on smolts feeding Feed loyalty: specific plant extracts are
were feeding within the first week following Chile. thanks to its unique expertise in taste
Table 1: Salmon diet composition behaviour. Fishes have a well-developed used as a natural source of alkaloids to
transfer, increasing to no more than 65 At the beginning of the trial, 252 Atlantic and smell physiology.
sensory system. induce habituation to the feed.
salmon smolts (Salmo salar, Ingredient % Based in Albi, in the South-West of
Depending on the species, they have The present trial confirms the effi- France, Phodé has 49 co-workers and
SalmoBreed strain), weighing
a variable number of sensory receptors ciency of Optifeed® Aqua in optimising feed operates in over 20 countries through
100-120g, were transferred
"Transfer to seawater
located in various parts of their body, from intake in salmons after transfer to seawater. a network of local distributors and
to six 200-litre seawater LT Fish Meal-Norway 31.7
the tongue to the entire body surface Moreover the smolts were fed a diet with research partners. For more informa-
tanks (42 fishes/tank). The
Soybean meal 5.0 in the case of cat fish (the animal with a relatively high level of plant proteins, tion, visit www.phode.com
experiment was conducted
represents a stressful in triplicates over a six-week
period (January-February
Soy Protein Concentrate 10.0
the larger number of gustative receptors!).
Salmons have 3000-4000 receptors. To this,
potentially representing a second stress fac-
tor with negative impact on their appetite.
event and can have 2009). Three tanks were allo-
cated to each diet: control
Hydrolysed feather meal
Wheat gluten
8.0
5.0
a detrimental effect (basal diet), and Optifeed®
Aqua treatment (basal diet
Wheat 12.0
plus 0.2 percent Optifeed® Fish oil (NorSalmOil) 24.3
on smolts feeding Aqua KX 81 P1).
The basal feed contained
Vitamin premix 2.0
The natural choice for
behaviour" 31.7 percent fishmeal and
24.3 percent fish oil (see
Mineral premix 0.4
Core vacuum coating
L-Lysine HCl 0.38
table 1).
The feed was extruded and DL-Methionine 0.2 0ptimum penetration of liquid
percent after five weeks. vacuum coated with the oil. Feed nutritional
High energy feed
Carophyll Pink (10%
Reducing this gap in feed consumption is analysis was: 43.8 percent crude protein, 6.6 0.064
www.forberg.no
astaxanthin)
an important factor to optimise production percent moisture, 6.8 percent ash and 28
Mono calcium phosphate 1.0
and reduce economic losses. A sensory feed percent fat. Both feed were given by auto-
24 | InternatIonal AquAFeed | January-February 2010 January-February 2010 | InternatIonal AquAFeed | 25

3. This digital re-print is part of the January | February 2010 edition of International Aquafeed magazine.
Content from the magazine is available to view free-of-charge, both as a full online magazine on our
website, and as an archive of individual features on the docstoc website.
LINKS
Please click here to view our other publications on www.docstoc.com.
VO L U M E 1 3 I S S U E 1 2 0 1 0
• See the full issue
Evaluation of Fishmeal
Substitution • Visit the International Aquafeed website
Utilization of spray-dried
Hemoglobin powder
- in Shrimp feeds
Active ingredients for
healthy animals
• Contact the International Aquafeed Team
- Rice, the technological ingredient
for aquafeed
Opportunities for fish
pheromones:
- their applications and role in the • Subscribe to International Aquafeed
sustainability of wild fish stocks
THE INTERNATIONAL MAGAZINE FOR THE AQUACULTURE FEED INDUSTRY
Member of the World Aquaculture Society, European Aquaculture Society, American Feed Industry Association
and the International Aquafeed Association
IAF1001.indd 1 12/01/2010 09:39
To purchase a paper copy of the magazine, or to subscribe to the paper edition please contact
our Circulation and Subscriptions Manager on the link above.
INFORMATION FOR ADVERTISERS - CLICK HERE
www.aquafeed.co.uk