Slice 2 mg/g Premix for Medicated Feeding Stuff

The fish feed medicated with the veterinary medicinal product is to be prepared only at
commercial fish feed mills and not at fish farms. The veterinary medicinal product is to be
coated onto feedstuff of the following type: Extruded cylindrical pellets of varying thickness
and length, e.g., 3.5 mm, 5.0 mm, 7.0 mm and 10.0 mm.
Recommended Method of Incorporation:
The veterinary medicinal product may be coated onto the surface of non-medicated fish
feed in the following manner:
a. Standard feed is transported by a conveyor belt to a fractioning sieve where dust and
fragments are sorted out.
b. The sorted pellets are transferred to an intensive mixer.
c. The pellets are dry-mixed/coated with a pre-determined amount of the veterinary
medicinal product for up to 2 minutes.
d. 0.5% to 1% fish or vegetable oil is added and mixing continued for up to 5 minutes.
The added oil seals the premix powder to the feed pellet.
e. At the completion of mixing, the product is transferred to a feeder tank for packaging
into sacks.
The recommended maximum number of marine treatments is 5 per 2 year growth cycle
and not more than 3 per 12 month period.
Smolts should only be treated when raised either in tanks or in flowing waterways (see
contra-indications).
Smolts should be transferred to seawater 1 - 2 days after the seven day treatment period
has ended.
To reduce the possibility of resistance development in sea lice it is recommended that
emamectin benzoate is used in integrated control programmes with the following
considerations:
•
•
consumption
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•
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•
infestation
•
and fallowing between production cycles
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other natural agents such as cleaner fish.
It is important that the level of infestation and the effectiveness of control measures are
monitored by routine counting of sea lice stages on samples of representative fish. Counts
should be conducted on at least five fish from each of 20% of cages on the farm at weekly
intervals in summer and every second week in winter. Treatment should only be initiated
when the number of sea lice per fish reaches a level so that effective sea lice population
control can be established.
4.10 Overdose (symptoms, emergency procedures, antidotes), if necessary
Emamectin benzoate administered to Atlantic salmon smolts in freshwater at 5.4 times the
recommended dose produced dark skin colouration and incoordination during the
treatment period.
Emamectin benzoate administered to Atlantic salmon in seawater at seven times the
recommended dose produced lethargy, dark skin colouration and incoordination
commencing on the fifth day of medication and inappetence commencing two days after
treatment.
Recovery was not evident in the week following treatment, in either fish treated in
freshwater or in seawater. There is no known antidote.
4.11 Withdrawal period(s)
Zero days.
To ensure that tissue residues do not exceed the MRL, fish must not be treated more than
once in the 60 days prior to the first fish being harvested for human consumption.
5. PHARMACOLOLGICAL PROPERTIES
Pharmacotherapeutic group: Avermectin class of endectocides
ATCvet code: QP54AA06
5.1 Pharmacodynamic properties
Emamectin benzoate is a semi-synthetic avermectin. Avermectins are macrocyclic
compounds produced by the soil microorganism Streptomyces avermitilis and are
characterised by a 16-membered lactone ring with an attached dioleandrosyl group.
The precise mechanism by which emamectin benzoate kills the various sea lice species
has not been elucidated. However, extensive research on the mode of action of
avermectin compounds against invertebrate species has shown that the avermectins
competitively bind to glutamate-gated chloride channels on invertebrate nerves. The

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distribution of glutamate-gated chloride channels in the invertebrate may be localised to
specific muscles such as those of the pharyngeal pump.
5.2 Pharmacokinetic particulars
Emamectin benzoate is relatively slowly absorbed but it is also widely distributed to the
tissues. Excretion is also relatively slow.