FISH NUTBITION
467
(Halver, 1957). Recently Hashimoto et al. (1970) have described another
thiamine deficiency symptom in the eel (Anguilla japonica). This is a
form of ataxia resulting in ( ( stiff flexion or winding of the body trunk ”.
As the condition advanced ( ( the body became stiff and revealed severe
bending.” The effect may resemble some forms of neuritis in warm
blooded animals.
Thiamine requirements of fish appear to be of the order of 0.1 to
0.2 mg/kg body weight/day but as thiamine is closely concerned with
carbohydrate metabolism the requirement will depend on the carbohydrate content of the diet. This is clearly shown by reference to the
experience of Aoe and his colleagues with carp (Aoe et al., 1967c, 1969).
I n their earlier work in which Halver’s (1957) diet was used they were
unable to demonstrate a requirement for thiamine in carp. When
however a high carbohydrate diet was used (that of Buhler and Halver
(1961) but without thiamine) thiamine deficiency symptoms were
manifested. Even so the thiamine requirements of carp appear to be
remarkably low.
With regard to the thiamine status of the fish Halver (1969) has
shown that erythrocyte transketolase activity is rapidly affected by a
thiamine deficiency and may be a useful biochemical tool in assessing
the adequacy of the dietary thiamine supply to the fish. Transketolase
is fairly typical of the reactions mentioned above and involves the
cleavage of ribulose-5-phosphate during the oxidative catabolism of
glucose.
An enzyme (thiaminase) which will destroy thiamine occurs in the
tissues of some 6.sh (especially certain freshwater species) and the
hazards of using such material in an unpasteurized form as food for
other creatures (including fish) need hardly be stressed (Krampitz
and Woolley, 1944; Jacobsohn and Azevedo, 1947).
2. Ribojlavin
The riboflavin moleoule is composed of a ribose moiety attached to
an isoalloxazine nucleus. Two coenzyme forms of the vitamin occur,
namely flavine mononucleotide (riboflavine 5’-phosphate, VI) and
flavine adenine dinucleotide. In the strict chemical sense the former is
not a nucleotide, as it contains a ribityl derivative and is not a glycoside.
These coenzymes function widely in carbohydrate metabolism where
their general role is that of hydrogen transfer from nicotinamide adenine
dinucleotides (the coenzymes I and I1 of older terminologies) to the
cytochrome system. They are part of the large and complex system
involved in the transfer of hydrogen from substrates to molecular
oxygen.
467
(Halver, 1957). Recently Hashimoto et al. (1970) have described another
thiamine deficiency symptom in the eel (Anguilla japonica). This is a
form of ataxia resulting in ( ( stiff flexion or winding of the body trunk ”.
As the condition advanced ( ( the body became stiff and revealed severe
bending.” The effect may resemble some forms of neuritis in warm
blooded animals.
Thiamine requirements of fish appear to be of the order of 0.1 to
0.2 mg/kg body weight/day but as thiamine is closely concerned with
carbohydrate metabolism the requirement will depend on the carbohydrate content of the diet. This is clearly shown by reference to the
experience of Aoe and his colleagues with carp (Aoe et al., 1967c, 1969).
I n their earlier work in which Halver’s (1957) diet was used they were
unable to demonstrate a requirement for thiamine in carp. When
however a high carbohydrate diet was used (that of Buhler and Halver
(1961) but without thiamine) thiamine deficiency symptoms were
manifested. Even so the thiamine requirements of carp appear to be
remarkably low.
With regard to the thiamine status of the fish Halver (1969) has
shown that erythrocyte transketolase activity is rapidly affected by a
thiamine deficiency and may be a useful biochemical tool in assessing
the adequacy of the dietary thiamine supply to the fish. Transketolase
is fairly typical of the reactions mentioned above and involves the
cleavage of ribulose-5-phosphate during the oxidative catabolism of
glucose.
An enzyme (thiaminase) which will destroy thiamine occurs in the
tissues of some 6.sh (especially certain freshwater species) and the
hazards of using such material in an unpasteurized form as food for
other creatures (including fish) need hardly be stressed (Krampitz
and Woolley, 1944; Jacobsohn and Azevedo, 1947).
2. Ribojlavin
The riboflavin moleoule is composed of a ribose moiety attached to
an isoalloxazine nucleus. Two coenzyme forms of the vitamin occur,
namely flavine mononucleotide (riboflavine 5’-phosphate, VI) and
flavine adenine dinucleotide. In the strict chemical sense the former is
not a nucleotide, as it contains a ribityl derivative and is not a glycoside.
These coenzymes function widely in carbohydrate metabolism where
their general role is that of hydrogen transfer from nicotinamide adenine
dinucleotides (the coenzymes I and I1 of older terminologies) to the
cytochrome system. They are part of the large and complex system
involved in the transfer of hydrogen from substrates to molecular
oxygen.