• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.67-72
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• 2022

We investigated the changes in the egg diameter of chub mackerel Scomber japonicus with the stages of egg development (and distinguished between hydrated oocyte and non-hydrated oocyte) for 1, 2, 3, 5, 10, 15 and 30 days. The chub mackerel oocytes were preserved in seven fixing solutions (70% ethyl alcohol, 99.9% ethyl alcohol, 5% formalin, 10% formalin, 5% neutral buffered formalin, 10% neutral buffered formalin and Gilson's solution). At 30 days, the chub mackerel hydrated oocytes preserved in 70% ethyl alcohol and 99.9% ethyl alcohol had shrunk by 5.2% and 7.9%, respectively. Similarly, the non-hydrated oocytes in the same solutions shrunk by 10.3% and 14.0%, respectively. Oocytes preserved in Gilson's solution had an average egg diameter decrease in both the hydrated oocyte (by 16.9%) and non-hydrated oocytes (by 15.6%). The diameter of the preserved hydrated oocytes did not significantly differ between the 5% formalin, 10% formalin, 5% neutral buffered formalin and 10% neutral buffered formalin, with shrinkage percentages of 0.6%, 0.1%, 1.9% and 3.4%, respectively (P>0.05). Similarly, the shrinkage percentages of the non-hydrated oocytes were 4.3% (5% formalin), 5.5% (10% formalin), 4.3% (5% neutral buffered formalin), and 4.1% (10% neutral buffered formalin).

• Applied Microscopy
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• v.51
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• pp.3.1-3.6
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• 2021

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of dwarf rainbowfish (Melanotaenia praecox) belong to Melanotaeniidae using light and electron microscopes. The fertilized eggs were spherical with adhesive filament, transparent, demersal, and had a narrow perivitelline space and small oil droplets. The size of fertilized egg was 1.02 ± 0.18 mm (n = 30), and there were two kinds of adhesive filament on the fertilized eggs. The long and thick (diameter 12.22 ± 0.52 ㎛, n = 20) adhesive filaments were only at the area of animal pole, and short and thin (diameter 1.99 ± 0.23 ㎛, n = 20) adhesive filaments were around the long filaments. A micropyle was conical shaped with adhesive filament and located near the animal pole of egg. The outer surface of fertilized egg was rough side. Also, the total thickness of the fertilized egg envelope was about 7.46 ± 0.41 ㎛ (n = 20), the fertilized egg envelope consisted of two layers, an inner lamellae layer and an outer layer with high electron-density. And the inner layer was 8 layers. Collectively, these morphological characteristics and adhesive property of fertilized egg with adhesive filaments, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.10-12
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• 1986

Pettancylus nipponicus (freshwater limpet) collected from the Lake Choon Cheon were cultrued in aquarium and studied in the respects of an egg deposition and the developmental characters of cleavage. The species were collected only in the Lake Uiam and Choon Cheon and easily sampled on the debris like vinyls and cans. Those smooth surfaces were suitalble substrata for attaching. P. nipponicus, about 4 mm in adult, deposited an egg in one calcareous egg-capsule on the aquarium walls, while many eggs are surrounded in a jelly-like egg-envelope in the most gastropods. And another special features was that an egg-capsule was consisted of two valves and the suture was opended as hatching. A diameter of its egg was $55{{\mu}m}$ and the length of an egg capsule was $620{{\mu}m}$ and $510{{\mu}m}$ in long and short diameter, respectively. It took about 8 hours from beginning cleavage to 16-cell stage and about one year to become an adult.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.171-175
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• 2006

The aim of this in vitro study was to test the effect of microinjection (Mi) of foreign gene into the rabbit egg pronucleus and epidermal growth factor (EGF) addition on the blastocyst rate, the cell number and the diameter of embryos, and to determine possible relationships between embryo cell number and embryo diameter. Blastocyst rate was significantly decreased in gene- Mi (G-Mi/E0) group (63.1%) comparing to intact ones (83.5%, $p_1$<0.05). The addition of EGF at 20ng/ml (G-Mi/E20) or 200 ng/ml (GMi/ E200) to gene-Mi embryos did not affect blastocyst rate (65.6 and 55.2% resp.). As a control for Mi, the eggs were microinjected with the same volume of phosphate-buffered solution (PBS-Mi) instead of the gene construct solution. Cell numbers and embryo diameters were measured from embryo images obtained on confocal laser scanning microscope. Bonferroni-modified LSD test showed that the embryo cell number in PBS-Mi group was significantly lower ($p_1$<0.05) and in gene-Mi group was tended to decrease compared with intact embryos. Embryo diameter was not different among experimental groups. No effect of EGF given at any doses both on the cell number and embryo diameter was found. A positive correlation between cell number and embryo diameter was observed in all groups of embryos. Since embryo diameter was not changed under the influence of Mi or EGF addition in this study, this seems to be more conservative characteristics of the embryo morphology. These results suggest that the pronuclear microinjection compromises developmental potential of embryos, decreasing blastocyst rate and embryo cell number, whilst embryo diameter is not affected. No effects of EGF on studied parameters were confirmed. Declined quality of Mi-derived embryos is caused by the microinjection procedure itself, rather than by the gene construct used.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.44-54
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• 2002

The fresh eggs of African ostrich in Korea were used in this study to investigate their interior and exterior quality characteristics. In ostrich egg shape characteristics, long and short length were measured as 15.1~16.1 cm and 12.1~13.6 cm, respectively. The egg shape index was calculated as 81.0 and the egg shell showed a more g loss white in color than that of hen egg. Calculated breaking strength of egg shell and egg shell surface based on the equation were $41.155kg/cm^3$ and $804.7cm^2$, respectively. Average egg shell thickness including egg shell membrane was 1.89 mm and there are no differences among parts of the shell. The egg shell membrane thickness was 0.10 mm showing relatively thick in equator compared with that of blunt end. The ave rage number of egg shell pores was counted as $19.7/cm^2$ showing relatively high number of egg shell pores at point end and the total number of egg shell pores in an egg was estimated as 15,241. The relative port ion of each parts based on egg weight was estimated as 25.1% for egg yolk, 58.2% for egg white, 16.7% for egg shell and the ratio of egg yolk to egg white (Y/W) was 0.43. The average diameter and the ave rage height of ostrich egg white were 19.7 cm and 13.2 mm, respectively. Calculated the H.U (Haugh Unit) was -69.7 and the pH was 8.3. In ostrich egg yolk, the diameter, the height, the egg yolk index, and it's pH were calculated as 14.4 cm, 29.4 mm, 0.20, and 6.6, respectively. And the egg yolk color showed a more thin in yellow chroma compared with that of hen egg as due to it's thicker membrane.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.676-683
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• 2023

The development of the egg, larvae, and juveniles of Acheilognathus macropterus from the Wicheon stream of Nakdonggang River was investigated for early life history characteristics. The fish used in the study were collected from Wicheon stream located in Bian-myeon, Uiseong-gun, Gyeongsangbuk-do. The fertilized egg was 1.88±0.09 mm (n=30) in long diameter and 1.34±0.06 mm (n=30) in short diameter. After fertilization at a water temperature of 20℃, the egg took 31 h and 40 min to hatch. Newly hatched larvae had an average total length of 3.92±0.13 mm (n=30) and possessed a yolk sac the mouth and anus were not developed. Twenty days after hatching, the postflexion larvae had an average total length of 8.08±0.29 mm (n=30), with the tail tip fully bent at 45° and began feeding. Thirty-three days after hatching, the number of fin stems reached an integer with an average total length of 15.0±1.08 mm (n=30). In this study, differences in the egg size, hatching time, melanophore development period, and distribution location were confirmed between A. macropterus and allied species.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1402-1411
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• 2014

This study about morphological observation of pre- or post ovulated eggs obtained from artificially maturated female eels. Female eels were divided with two groups as wild eels from nature and feminized eels from farm. Artificial maturation had been conducted with the established methods in this laboratory, and then maturate eggs sampled at fixed 3 times and these were observed with stereomicroscope. Rate of increased body weight (RIW) were measured with 2 times. Egg diameters and development of oil droplets are determined for standardization of egg maturation degree, and the transparency of egg cytoplasm and the homogeneous degrees of egg size were referred to determine of egg quality. Rate of increased body weight (RIW) were good in range about 10 % at final salmon pituitary extracts (SPE) injection time and in range about 20 % at $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregnen-3-one (DHP) injection time. Good matured egg for fertilization had $900-1000{\mu}m$ diameter, and they had about 50 oil droplets in size about $100{\mu}m$ diameter. There were not predominant differences at egg size and oil droplet development between wild female and feminized eels.

• Korean Journal of Ichthyology
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• v.35 no.3
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• pp.151-159
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• 2023

This study investigated the early life history of the Micropercops swinhonis in Botongcheon stream Hangang River and compared the relationship between the related species and flexibility. The fertilized egg of the ovoid type, and the average egg diameter was 1.23 mm in long diameter and 0.85 mm in short diameter. At a water temperature of 20.6℃, the hatching time took 179 hours. The newly hatched larvae measured 3.82~4.08 mm in total length (TL), and their mouth and anus were not yet open. At 18 days after hatching, the postflexion larvae reached 7.97~8.43 mm in TL, with the tip of the caudal fin bent at 45°. At 29 days after hatching, the juveniles reached 9.83~10.8 mm in TL and were differentiated by their constant number of fins (7~10 first dorsal, 10~11 second dorsal, 7~10 anal fins). As a result of the study, there was a difference from the related species in the egg diameter, the newly hatched larva size. The postflexion larvae period and the development period of the first dorsal fin were the slowest among the comparable simila species, and the size was characterized by a large number, indicating a difference from similar species in the early life history process.

• Development and Reproduction
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• v.1 no.1
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• pp.91-97
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• 1997

In order to study the reproductive physiology of Sand ell(Hypoptichus dybowskii) catched at kangwon-do, Wooamjin Bay, spawning and egg development were investigated in April and May, 1996. The observed spawning period was from the middle of April to the end of May with the water temperature above $8^{\circ}$C. Body size and colouration were distinguished between male and female. The type of testicular structure is lobular, and the ovary is a pair of sac-sahaped covering with a fibromuscula capsule and comprising a mature egg of average 86. The unfertilzed egg are demersal and adhesive, and their diameter were 1.65-1.95 mm. the colour of yolk is light yellow and contained a lot of tiny oil globules. The average spawned egg was 62 in sargasso weeds. Hatching was observed in 12 days after fertilization with the water temperature of 14 ${\pm}1^{\circ}$C. The average size of larva after hatching was 6.85${\pm}$0.23mm in total length, and larva were containing yolk including globule.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.317-321
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• 2006

The effects of dietary humic substances (HS) on egg Production and egg Quality were studied using 252(55-wk old) ISA brown laying hens. laying were divided into 21 groups of 12 hens each and seven groups (experimental units) were assigned to 1) CON (basal diet), 2) HS5 (basal diet 4- 5% humic substances) or 3) HS10 (basal diet +10% humic substances) in a completely randomized block design. Hens had free access to diets and water fur 6 wk. Egg Production and egg quality were monitored over the 6-wk Period. Results showed that 10% dietary HS decreased egg Production and yolk diameter (P<0.05) compared to CON. Egg weight and yolk cole. were improved (P<0.05) in HS10 compared to CON. Egg shell breaking strength was increased significantly (P<0.05) when hens were fed HS5 diet compared to the others. There were no effects of treatments on egg shell thickness, yolk index, albumen height and Haugh nit. The results suggest that the dietary supplementation of HS at 5% or 10% decreases egg Production, but HS at 5% can increase egg shell breaking strength. Hens fed 10% HS could increase egg weight and yolk color and decrease yolk diameter.