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www.sciencepub.net New York Science Journal, 2010 (3; 11 )
14 hour of light daily. Hens were fed for a week and
their eggs were collected and analyzed to be certain
that no gentamicin residues contaminated the eggs
before beginning he experiment.
Experimental procedure:
Thirty two hens were assigned to 4 groups
(n=8). Groups 1 and 3 injected intramuscularly into
the pectoral muscles with 2 and 4 mg gentamicin/Kg
body weight/day for 3 days respectively. Groups 2
and 4 injected subcutaneously with 2 and 4 mg
gentamicin/Kg body weight/day for 3 days
respectively. Injection of drugs eliminates the
confounding influences of variation in drug exposure
due to differences in hens feeding or water
consumption tendencies (Donoghue et al., 1996). On
the day of the study, hens were monitored every 5
minutes to establish the time of oviposition. Injection
was given one hour after the daily oviposition to
synchronize time of injection to the daily phase of
yolk formation. Because ovulation occurs within
approximately 30 minutes after oviposition (Johnson,
1986). To insure that each group had eight hens,
additional hens (4 hens per group) has been used at
the start of the study and maintained as a spare to use
if any hen at any group didn't lay an egg or died
during the experimental period.
Analytic mehods:
The residues of genamicin in the eggs were
detected by modifying HPLC method recommemded
by the European Union (Heitzman 1994). Five grams
of the yolk and 5 grams of the albumen were taken
from the egg and the remaining part of the egg was
mixed and then 5 grams was taken from this mixture.
Thus he quantity of gentamicin in yolk, albumen and
whole egg was analyzed. Trichloracetic acid
(5%w/v)/1mM EDTA solution was added to the
samples in the tube; the samples were homogenized
and then centrifuged to precipitate the proteins. At he
end of this process, pH was adjusted to 0.7 and they
were filtered using a Sephadex G25 (Bakerbond Spe
Kolon) ion exchange column. The samples were
analyzed in the HPLC with post-column derivation
(Phenomex Luna C-18 column; 5 µm, 250 mm × 4.6
mm). The o-phthalaldehyde (.8% containing 0.2% 2-
mercaptoehanol and 0.1% Brij) was pumped at 0.5
ml per min and fluorescent peaks were detected at
400 nm. The total concentration of the gemtamicin
was calculated.
Recovery studies:
The gentamicin sulphate analytic standard
(Sigma G1914, Lot:070K1038), with purity of 665
µg/mg, was added to the yolk, albumen and the
whole egg whose concentration were 0.01, 0.02, 0.03,
0.05 and 0.07 µg/ml, and it was homogenized to
allow the extraction of the gentamicin from the eggs
and to establish the limit of detection. It was
extracted with the above-stated analytic method and
was applied to the HPLC.
Statistical analysis:
Data were analyzed by analysis of variance
using the Statistical Analysis System (SAS
software, 1994) general linear models program.
Treatment means were partitioned by least square
means (LS MEANS) analysis. A probability of
P≤0.05 was required for statistical significance.
Results:
Tables 1, 2 and 3 demonstrate gentamicin
residues detected in albumen, yolk and whole egg
during the dosing and withdrawal periods when hens
injected in different dosages via different routes
respectively. From dosing began on day 1, the first
egg contained gentamicin residues in the albumen but
the first yolk (day 1) didn't contain drug residues and
appeared from the second yolk (day 2). As shown in
Table (1) gentamicin residues in the albumen started
to decrease slightly after day 1 in the withdrawal
period but in he yolk and whole egg (Table 2 and 3)
the residues increased gradually and the highest
concentrations towards the middle of the withdrawal
period then the residues started to fall rapidly. Results
from this study demonstrate that gentamicin residues
were incorporated into albumen for 6 and 8 days for
dosing 2 and 4 mg/kg life body weight within the
withdrawal period respectively but in either yolk or
whole egg for 12 and 15 days respectively, after that
gentamicin residues disappeared completely
(<0.01µg/g). The gentamicin residues tolerance
levels reported by U.S.A.; Germany; France and
Holland were (0.1-0.4; 0.2; 0.1-0.2 and 0.1 mg/kg)
respectively (Lavzquez et al., 1990). It is clear that
the drug remained in the yolk for a long period and at
(This it the stuff that I used)
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