The Japanese quail tissues - liver, kidney and pancreas were analysed
for the presence of forms of xanthine oxidoreductase utilised cofactor
s NAD+, molecular oxygen or artificial acceptor - methylene blue, as w
ell as for the validity of correlation between enzymatic activity and
diet protein content. Four groups of animals with the experimental die
ts, the formulae of which are given in Tab. I, and control group with
a commercial mash were fed for ten days. For enzyme preparation, the r
ough purification of cytoplasmic fraction with subsequent dialysis was
used. The xanthine oxidoreductase utilised NAD+ (XOR-NAD) was detecte
d in all examined tissues (Fig. 1), whereby the correlation of enzymat
ic activity with diet protein content was shown only in liver, accordi
ng our previous findings (Jankela;1978; Baranovska and Gazo, 1990). Th
e values in liver and pancreas of animals fed a commercial mash were s
omewhat out of the range of linearity, probably because of the presenc
e of nonprotein substances in mash, which affected the XOR activity in
these organs (Jankela , 1992). The XOR utilised 02 (Fig. 2) was only
detected in liver and kidney with certain activity in animals fed free
protein diet. The percentage of this enzyme form was below 18 % of th
e total activity (Fig. 5). The xanthine oxidoreductase utilised methyl
ene blue (XOR-MM) was detected in liver, kidney and pancreas (Fig. 3).
The correlation of enzymatic activity with diet protein content was l
inear in liver and kidney. The percentage of XOR-MM activity was very
high, it amounted to 55 % of the total activity (Fig. 4). The joint de
termination of both forms of XOR (XOR-NAD+ and XOR-MM) may be a valuab
le tool for utilization of XOR activity as a marker of the nutritional
value of feed.