International Giant Otter Studbook Husbandry and Management
International Giant Otter Studbook Husbandry and Management
International Giant Otter Studbook Husbandry and Management
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Dietary Related Problems: Diarrhea <strong>and</strong> loss of appetite were caused by feeding fish in the<br />
reproductive state (i.e. when they carried eggs) (Lazzrini 1998, pers. comm.; Dortmund Zoo,<br />
pers. comm. 2001). (Fish eggs should be removed before feeding.) <strong>Giant</strong> otters have contracted<br />
helminthes from live-fed fish (Flügger 1997).<br />
When feeding giant otters “The fish has to be first quality, freshwater fish. Saltwater fish is<br />
taken, but contains too much fat.” Wünnemann (1995 b ). Also Hagenbeck & Wünnemann<br />
(1992) explain, “Marine fish, such as herring (Clupea harengus) <strong>and</strong> mackerel (Scomber<br />
scombrus) are preferred by the otters but are not given as we consider them too oily to offer a<br />
good balanced diet.” “Marine products contain high levels of poly- <strong>and</strong> mono-unsaturated fatty<br />
acids.” (Reed-Smith 2001). Nutrient values vary between fish species <strong>and</strong> even within the same<br />
species depending on age, sex <strong>and</strong> season of capture (Crissey 1998). Merck (1986) states<br />
“Many fresh-water <strong>and</strong> salt-water fishes contain thiaminase, an enzyme that results in thiamine<br />
[vitamin B 1 ] deficiency in animals fed exclusively on a diet of such fish.” Lewis (1995) states,<br />
with regards to mustelids, “Diets high in polyunsaturated fat or fish may predispose vitamin E<br />
deficiency.” The process of fish storage (freezing), thawing, <strong>and</strong> preparation causes fish<br />
nutrient loss, particularly vitamins B 1 <strong>and</strong> E, <strong>and</strong> especially in fish with a high fat <strong>and</strong>/or high<br />
thiaminase content (Crissey 1998, Merck 1986). Fish types containing high thiaminase <strong>and</strong>/or<br />
high polyunsaturated fat levels should be avoided, as they can cause malnutrition, sickness <strong>and</strong><br />
even death (Merck 1986). Vitamin supplements, most especially vitamin B 1 (thiamine), vitamin<br />
E, <strong>and</strong> a multivitamin, must be added when thawed frozen fish is the main diet. See Chapter 2<br />
Section 19 for information on diets.<br />
The following problems could be caused by feeding inappropriate diets, although these<br />
problems have not been reported (see the paragraph below) to occur among giant otters:<br />
(Following are excerpts from Reed-Smith, 1994-1995). “Thiamine (B1) - Thiamine deficiency<br />
is also known as Chastek's paralysis. Clinical signs include, anorexia, salivation, ataxia,<br />
incoordination, pupillary dilatation, <strong>and</strong> sluggish reflexes. Chastek's paralysis: "..a vitamin B1<br />
deficiency induced by feeding certain types of raw fish that contain the enzyme thiaminase. "<br />
(Merck, 1991) Early in the disease an abnormal gait, as if the hind legs were stiff, will be<br />
observed. This leads (within 12 - 36 hours) to "extensive spastic paralysis" <strong>and</strong> the animal will<br />
be unable to rise. It is treated by removing fish from the diet (then substituting fish that do not<br />
contain thiaminase) <strong>and</strong> "daily injections of 100 u of thiamine..”. (Merck, 1991). “Vitamin E<br />
Deficiency (yellow fat disease, steatitis) is produced by feeding high percentages of long-chain<br />
polyunsaturated fatty acids provided in fish oils or horse fat." (Wallach & Boever 1983).<br />
Clinical signs may include lethargy, lumpy subcutaneous fat, rear leg weakness <strong>and</strong> death.”<br />
(End of excerpts.)<br />
See under “Vomiting” <strong>and</strong> “Walking Difficulties Involving the Lower Back <strong>and</strong> Hind Legs”<br />
(i.e. under “acute severe walking difficulties that occur suddenly <strong>and</strong> that last only for a brief<br />
period of time”) below for more information about diets.<br />
Excessive humming vocalizations: <strong>Otter</strong>s have nine different vocalization types <strong>and</strong> many subcategories<br />
exist for each type (Duplaix 1980). Normally humming is a positive contact<br />
vocalization. Although when otters hum excessively (i.e. hum for an abnormally long time<br />
or/<strong>and</strong> unusually frequently) this is not necessarily a positive sign <strong>and</strong> these sounds can mean<br />
that the otters are stressed, nervous or anxious (Sykes-Gatz & Gatz pers. obs.).<br />
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