12
M
arch
2011
Methods and Materials
1. One gram of dry cysts are added to of 1,000 cc of 35 ppt
salinity water and aerated.
2. After one hour, six samples are taken from replicates.
3. The total number of cysts in each the six samples are
counted (including those cracked, fully cyst: hydrated
or dehydrated cysts). The mean is calculated for the six
samples so the total number of cysts can be calculated.
4. Immediately, the cysts are decapsulated with sodium
hypochloride. At this stage shells and the cysts with im-
perfect embryos are eliminated but the cracked and full
cysts remain and are decapsulated. Then, the decapsu-
lated cysts are counted and mean from the replicates
is obtained to determine the total number of decapsu-
lated cysts.
5. After 24 hours (hatching time), the percentage of false
hatching (%PFH) is calculated by the method of Van
Stappen (1996).
Summing the Nauplii + Umbrella + Embryos shows
the number of full cysts containing embryos (Van Stappen
1996).
6. Other conditions required for hatching must be ob-
served.
7. All experiments should be repeated three times.
Finally, the value of each defined parameter is computed.
Hatching quality of cysts from three species of
Artemia
(
A. urmiana
,
A. franciscana
and a parthenogenetic popula-
tion) were evaluated following the new concepts.
2. Percentages of Absolute Hatching (%AH): is the num-
ber of larvae harvested from 100 embryo-bearing cysts
whether perfect or cracked.
3. Percentage of Cyst Purity (%Cyst Purity): percentage of
perfect and perfect embryo-bearing cysts out the total
embryo-bearing cysts whether perfect or cracked
4. Shell Percentage (%Shell): the percentage of shells and
imperfect embryo-bearing cysts
5. Percentage of Cracked Cyst (%Cracked Cyst): the per-
centage of cracked embryo bearing cysts out of total
embryo bearing cysts
6.
Percentage of Hatching Potential Loss (%HPL): the dif-
ference between the %FH and %PH that indicates the
potential loss due to existence of cracked cysts and sells.
The lower the loss percentage and the higher the poten-
tial hatching, the better the quality of the cysts.
The abbreviations FH, PH, AH and HPL are used in Figure
1 and Table 2.
Table 1. Raw data from the study.
Sample
Repetition Total Cyst
Total decapsulated Nauplii
Umbrella
Embryo
1
98.32
57.9
22.83
7.66
13.33
Parthenogenetic population
2
-
-
-
-
-
3
87.5
57.07
25.66
6.83
16
1
98.32
54.15
20.5
7.16
14.16
A. urmiana
2
102
55.4
19
6
13.33
3
80
51.65
20
4.16
13
1
88.75
46.87
33
7.5
5
A. franciscana
2
91.25
56.87
37.25
7
7.5
3
91.25
56.25
39.5
9.25
7
Table 2. Mean (S.D
)
of the results of cysts quality (same letters in each column show significant difference, ANO-
VA; Tukey, p<0.05)
Sample
%PH
%AH %FH %Cyst Purity HE
%shell
%cracked %HPL
Parthenogenetic
Artemia
26.27 (4.32)a 42.20 (3.91)a 52.51 (0.58)a 80.32 (6.56)a 96980(8004)a 37.94(4.48)
19.68(6.56)a 10.31(3.33)a
A. urmiana
21.49 (3.23)b 36.96 (2.35)b 50.80 (2.63)b 72.79 (4.09)b 79333(3055)b
42.02(5.71)
27.21(4.09)b 13.84(2.33)b
A. franciscana
40.43 (3.07)ab 68.71 (2.78)ab 71.79 (0.85)ab
95.73 (4.22)ab 146333(13203)ab 41.07(5.31) 4.27(4.22)ab 3.08 (3.04)ab
1...,4,5,6,7,8,9,10,11,12,13 15,16,17,18,19,20,21,22,23,24,...76