3. Results and discussion
3.1. Nitrite and nitrate concentrations
The nitrite contents found in house nests and cave nests were
5.7 ± 6.7 lg/g and 843.8 ± 460.9 lg/g, respectively. Among the
house nests, H1 and H2 showed undetectably low nitrite
contents which were less than 0.1 lg/g. The nitrite contents
in cave nests were 148-fold higher than house nests. The
nitrate contents obtained in house nests and cave nests
were 98.2 ± 33.7 lg/g and 36,999.4 ± 38,738.7 lg/g, respectively.
The nitrate contents in cave nests were 377-fold higher than
house nests. In general, the nitrite and nitrate contents in
cave nests were significantly higher (P < 0.05) than house
nests (Fig. 1). The results also showed that nitrate contents
were much higher than the nitrite contents for house nests
and cave nests. This is because nitrate has a more stable
form and can be generated from nitrite oxidation [18]. The
nitrite and nitrate analysis of edible bird’s nest were determined
in duplicates. These results were considered robust
at 99% high confidence levels using one-way ANOVA.