Menadione Nicotinamide Bisulfite Is a Bîoactîve Source of ...

niacin bioactivity of MNB when compared with
nicotinamide (U.S. Biochemicals, Cleveland, OH). On
d 8 posthatching, quadruplicate groups of four male
chicks were assigned to the following dietary treat
ments: 0, 2.5, 5.0 and 30 mg/kg nicotinamide (the
latter a positive control) or 0, 2.5 and 5.0 mg/kg
nicotinamide from MNB. The NRC (1984) estimate of
the dietary nicotinic acid requirement of young
chicks is 27 mg/kg. On d 22 posthatching, chicks and
feed were weighed, and chick weight gain, feed intake
and feed efficiency were determined. Chicks that had
been fed 0 and 5.0 mg/kg nicotinamide (from both
MNB and nicotinamide) were killed by cervical dislo
cation at d 22 posthatching, and portions (0.25 g) of
liver tissue were removed and pooled by replicate.
Liver samples were homogenized and heated in a
boiling water bath for 5 min. Hepatic pyridine nucleotides
(NAD + NADH) were then determined by the
enzyme-cycling
(1969).
procedure of Nisselbaum and Green
Toxicity assays. Assay 3 was conducted to de
termine the toxic effects of an acute oral (crop intu
bation) dose of menadione from MPB (as a standard)
or MNB. Preliminary work in our laboratory had es
tablished that doses of MNB or MPB providing mena
dione at 500 mg/kg body weight or less caused neither
mortality nor morbidity. Assay 3 was therefore
designed to provide logarithmic doses of menadione,
starting at 100 mg/kg and working up to 1600 mg/kg
body weight. Following dosing at d 8 posthatching,
triplicate groups of four chicks at each dose level were
fed a 23% protein corn soybean meal starter diet5 for
a 14-d observation period.
Assay 4 was a 14-d chronic toxicity study involving
triplicate groups of four chicks at each menadione
dose level (0, 30, 300, 3000 and 6000 mg/kg diet) from
MPB or MNB. Additions were made to the cornsoybean
meal starter diet. At termination of the assay
on d 22 posthatching, blood was obtained by heart
puncture after which 1-mL portions from each chick
in a pen were pooled, resulting in three pooled
samples for each of the nine treatments. Blood hemo
globin was determined by the method of Crosby et al.
(1954).
Statistical analyses. Common-intercept multiple
linear regression was conducted for data in Assays 1
and 2 using the General Linear Model procedure of
SAS (1985). Data were first fitted to simple linear
regression equations to establish that Y-intercepts
were not different (P > 0.05) after which the multiplelinear
regression model was fitted
menadione biopotency assessment
to the data. For
in Assay 1, prothrombin
time (s) was regressed on supplemental
menadione intake (/¿g); for nicotinamide biopotency,
weight gain (g) was regressed on supplemental
nicotinamide intake (mg). The ratio of slopes (MNB:
MPB) gave estimates of menadione or nicotinamide
potency for MNB relative to MPB.
MENADIONE NICOTINAMIDE BISULFITE 739
TABLE 2
Prothrombin time of chicks fed diets with graded levels of
menadione from menadione dimethylpyrimidinol bisulfite
(MPB) or menadione nicotinamide bisulfite (MNB) (Assay I)1
menadioneUS/kg052550400ProthrombinMPBs3528252519time3MNB3533272417
'Values are means of duplicate groups of four male chicks at d
22 posthatching; average initial weight was 76 g.
The basal vitamin K assay diet (Table 1) was estimated to
contain 0.05) and this indicated that MPB and
MNB were equally efficacious in furnishing bioavailable
menadione.
Nicotinamide activity. Addition of graded doses of
nicotinamide or MNB below the niacin requirement
yielded linear (P < 0.01) responses in weight gain, feed
5Contained (g/100 g): corn, 52.8; dehulled soybean meal, 37.0;
alfalfa meal, 1.0; menhaden fish meal, 2.0; corn oil, 4.0; dicalcium
phosphate, 2.20; limestone, 1.00; DL-methionine, 0.20; NaCl, 0.40;
trace mineral premix (Mn, Fé,Zn, Cu, I, Se), 0.15; flavomycin
premix (4.4% flavomycin), 0.05; vitamin premix (retinyl acetate,
cholecalciferol, all-rac-a-tocopheryl acetate, menadione sodium bi
sulfite, vitamin B-12, niacin, D-Ca-pantothenate, riboflavin), 0.10;
choline chloride (60% choline), 0.10.
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