Menadione Nicotinamide Bisulfite Is a Bîoactîve Source of ...

740 ODUHO ET AL.
intake and gain:feed ratio (Table 3). Responses at 5
mg/kg nicotinamide were far lower (P < 0.01) than
those obtained when 30 mg/kg nicotinamide was sup
plemented. Hepatic NAD + NADH concentrations
were low in chicks fed the basal diet, but they in
creased (P < 0.05) upon adding 5 mg/kg nicotinamide
from either nicotinamide or MNB. Multiple linear
regression of weight gain (g) as a function of
nicotinamide intake (mg) resulted in a good fit (R =
0.98), with the MNB slope being 87% of the slope
value for nicotinamide (Fig. 2). Regression coefficients
(i.e., slopes), however, were not significantly different
(P > 0.05) between the two sources of nicotinamide.
Acute toxicity of menadione nicotinamide bi
sulfite. Single crop intubations of MPB or MNB at
menadione doses of 800 mg menadione/kg body
weight or lower did not cause mortality, nor was
growth depressed during the subsequent 14-d obser
vation period (Table 4). With a dose of 1600 mg/kg
body wt, however, 3 of 12 chicks (25%) receiving
MPB and 2 of 12 chicks (17%) receiving MNB died in
the first 2 d following dosing. This dose of menadione
from MNB but not MPB caused a depression in
weight gain, feed intake and gain:feed ratio during the
14-d post-dosing period.
Chronic toxicity of menadione nicotinamide bi
sulfite. Pharmacologie doses of MNB or MNB
provided in the diet at levels up to 6000 mg/kg mena
dione resulted in no mortality during the 14-d feeding
period. At 6000 mg/kg menadione, both sources of
menadione depressed (P < 0.05) gain, feed intake and
gain:feed, but only MNB depressed blood hemoglobin
concentration (Table 5). At 3000 mg/kg menadione,
MPB produced no morbidity, but MNB depressed all
measures of chick performance.
DISCUSSION
Menadione nicotinamide bisulfite
is an organic salt of two vitamins, menadione bi
sulfite and nicotinamide (Fig. 1). According to the
manufacturer (Vanetta SPA), MNB, a pale yellow
powder, has a melting point of 182°C,a pH range of 1
to 3.5 and a water solubility (25°C)of 19 g/L.
The one-stage prothrombin time chick bioassay
(Quick 1957) is considered the most sensitive assay
for biopotency of menadione compounds (Augustine
1985, Griminger 1965, Kindberg and Suttie 1989). In
our hands the prothrombin time assay worked far
better (i.e., better linearity) with thromboplastin iso
lated in our laboratory from chicken brain than was
the case with purchased rabbit thromboplastin. This
agrees with results reported by Griminger (1962).
Griminger (1965) and Griminger and Donis (1960)
used a vitamin K-assay diet similar to that used
herein, and their 21-d-old female chicks appeared to
be more deficient in vitamin K than was the case with
0.5
SupplementalNicotinamideIntake (mg/14d)
FIGURE 2 Multiple linear regression of weight gain (Y in
g) on supplemental nicotinamide intake [X in mg) from
nicotinamide (X, *) or MNB (X2, +): Y = 79.3 + 72.7 (±5.3)X\
+ 63.2 (±5.7)Xi, R = 0.98.
our unsupplemented male chicks. They used sulfaquinoxaline
(2 g/kg) to minimize gut synthesis of
vitamin K. We used 2 g/kg sulfathiazole in our
vitamin K-deficient diet, and this sulfa drug may have
been less effective than sulfaquinoxaline in
minimizing gut synthesis of the vitamin. In
Griminger's (1965) work, MSBC was 74% as effective
as MPB in furnishing bioavailable menadione. In our
study (Table 4), MPB and MNB were equally effective
in furnishing bioavailable menadione.
Based upon prothrombin times of 17 to 19 s at 400
Mg/kg menadione (Table 2), with normal prothrombin
times for chickens assumed to range from 12 to 25 s
(Smith and Russell 1984), it would appear that the
NRC (1984) estimate of 500 Mg/kg for a vitamin K
requirement of broiler chickens is a reasonable es
timate of the true requirement.
Growth bioassays in chicks work well to establish
niacin activity of test ingredients (Baker et al. 1973
and 1976, Jacob and Swenseid 1990), but if the test
sources contain tryptophan as well as nicotinic acid
or nicotinamide, it is difficult to separate niacin
responses from tryptophan responses (Baker 1986).
Our niacin assay diet contained corn, corn gluten
meal and casein. We assumed that nicotinic acid
would be only 20% available in corn and corn gluten
meal (Darby et al. 1975, Yen et al. 1977) and that
bioavailable tryptophan would be relatively low in
these ingredients as well (Yen et al. 1971). We were
therefore surprised that the niacin assay diet, when
adequately fortified with nicotinamide, would not re
spond to supplemental tryptophan. Regardless, the
diet responded markedly to nicotinamide addition,
and the fourfold growth response obtained to addition
of 30 mg/kg nicotinamide (Table 3) suggested that
lower doses of nicotinamide would result in linear
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