3.2. Fish proximate composition
The dietary administration of peppermint at 1%, 2% or 3% for 8
weeks did not change the moisture, the crude lipid and protein and
the ash present in carcasses of Caspian white fish, respect to the
values found in control fish (fed non enriched diet) (Table 3).
3.3. Skin mucus activities
The skin mucus of Caspian white fish fry showed antimicrobial
activity against all the tested pathogens (Tables 4 and 5). Furthermore,
feeding on peppermint-supplemented diets caused a significant
increase in antibacterial activity compared to the control
treatment (P < 0.05). The bacterial growth inhibition zone diameter
(mm) of the skin mucus obtained from Caspian roach fry fed
different levels of M. piperita (control, 0%, 1%, 2% and 3%) for 8
weeks is shown in Table 4. The growth of all the bacteria species
tested (S. iniae, Y. ruckeri, L. monocytogenes and E. coli) was statistically
significant inhibited(p < 0.05) when mucus were obtained
from fish fed peppermint supplemented diet, compared to the
values find from fish of control group. The inhibition was always
higher in those mucus samples from fish fed the highest peppermint
concentration (3%). The results of the MIC of Caspian white
fish fry skin mucus were similar to those of antimicrobial activity
(Table 5).
The protein concentration present in fish skin mucus increased
in a dose dependent manner respect to the peppermint supplement
present on diet, respect to the levels find in mucus from
control fish (Table 6). Those fish fed 3% peppermint supplement
diet showed the highest protein concentration on skin mucus.
Similar results were obtained when alkaline phosphatase activity
was studied (Table 6).
3.4. Hematology
All the hematological parameters studied in the present work
were increased in a dose dependent manner in fry fish fed diets
supplemented with peppermint. The number of blood cells was
also increased as a consequence of dietary administration of
M. piperita to fry Caspian white fish. More concretely, the number of
total red blood cells was increased in a statistically significant