• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.6
• /
• pp.899-904
• /
• 2018

Objective: This experiment studied the effects of first feed intake time post-hatch on growth performance, nutrient apparent metabolic rate and intestinal digestive enzyme activities in broilers. Methods: Two thousand five hundred and twenty LingNan Yellow broilers were randomly allotted to seven treatments with six replicates of 60 each. The only experimental factor was the first feed intake time which was 18, 24, 30, 36, 42, 48, and 54 hours after hatching. The whole experiment lasted for 21 days. Results: During the whole period, the 30 h treatment had the best body weight and average daily gain (p<0.05), followed by the 24 h group performance optimization. Also, the 30 h group was observed to have the best apparent metabolic rate for ether extract (p<0.05) and crude protein (p<0.05) and the highest activities of amylase, lipase and trypsin in small intestine. And the 24 h group was second only to the 30 h group in terms of the above two measures. Conclusion: These results indicated that the appropriate first feeding time of LingNan Yellow broilers was 24 to 30 hours after hatching.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.17 no.2
• /
• pp.165-168
• /
• 2008

The hybrid ($CSR2{\times}CSR4$) eggs treated with acid were taken up for the study with an objective to develop long-term preservation schedule. The hybrid eggs obtained with two mating duration (3 h and 6 h) and oviposition period (6 h and 24 h) with two age groups of eggs (24 h and 36 h) were treated with Hydrochloric acid. These eggs were subjected to preservation at $5^{\circ}C$ in single step refrigeration and at $5^{\circ}C$ and $2.5^{\circ}C$ under double step refrigeration from $10{\sim}120$ days. These eggs were released from the cold storage as per the specified durations and incubated at standard conditions and allowed 2 h for hatching at 450 lux light. Hatchability was found to be significantly higher or on par with the control in three treatments (T1, T2 and T4) where the eggs are preserved continuously at $5^{\circ}C$ up to 30 days. However under double step refrigeration, hatching was not significantly affected in 20+60 day's combination of T1 treatment up to 80 days. Bioassay studies of the promising treatment i.e.. T1 with (20+60) days indicated that early stage loss and cocoon yield was found to be on par with the control. Hence this treatment was recommended for preservation of acid treated new bivoltine hybrid layings. Details of the hatchability and rearing performance of long term preservation of acid treated eggs are discussed.

• Korean Journal of Ichthyology
• /
• v.17 no.2
• /
• pp.105-111
• /
• 2005

Most of the eggs and (or) pre-larvae of Acheilognathus signifer were observed from the gills of Unio douglasiae sinuolatus, 30~45 mm in the shell length, that is the host mussel of A. signifer. There was no selectivity in proportion to mussel size at the range observed. One to seven individual eggs and (or) pre-larvae were found in the mussels, with a mean of 2.5 individuals, and the rate of possessing one egg and (or) pre-larva was 50.0%. When the prelarva of A. signifer acquired swimming ability inside the mussel, it moved into the suprabranchial chamber. It was estimated that the growth period was 4~6 weeks. The minute tubercles of the pre-larvae were observed immediately after hatching. Absorption of the minute tubercles was observed starting the 7 th day, with most of tubercles absorbed 13 days after hatching and completed 20 days after the yolk was entirely absorbed.

• Clinical and Experimental Reproductive Medicine
• /
• v.39 no.3
• /
• pp.118-124
• /
• 2012

Objective: To review the outcomes of preimplantation genetic diagnosis (PGD) using zona drilling with acid Tyrode's solution (chemical zona pellucida drilling, chemical ZD) and those of partial zona dissection (PZD). Methods: Clinical outcomes of seventy-one couples undergoing 85 PGD cycles from January 2005 to December 2010 were included. Blastocyst formation and the hatching rate, clinical pregnancy rate, ongoing pregnancy rate, implantation rate, and fetal gender ratio of the PZD and chemical ZD groups were compared. Results: Application of PZD resulted in a significantly higher rate of clinical pregnancy (40.7% vs. 15.4%, p=0.022), ongoing pregnancy (35.6% vs. 11.5%, p=0.023), and implantation (18.1% vs. 5.7%, p=0.007) compared with chemical ZD. Among non-transferred embryos, the rate of blastocyst formation on day 5 (49.1% vs. 39.5%, p=0.016) and hatching on day 6 (47.2% vs. 26.5%, p<0.001) were also significantly higher in the PZD group. Conclusion: The mechanical zona dissection (ZD) method showed better outcomes than chemical ZD in terms of the blastocyst development and pregnancy rate. In this study, the fact that chemical ZD was conducted in different period from mechanical method should be considered in interpreting the result.

• The Korean Journal of Malacology
• /
• v.9 no.2
• /
• pp.1-15
• /
• 1993

The reproductive ecology of the purple shell, Rapana venosa was investigated by the histological observations on depositions of the egg capsules, and hatching of larvae in the laboratory and the subtidal zone of the vicinity of piung-do, Chollabud-do, west coast of korea, for one year from June 1992 to May 1993. The results are summarized as follows:1. Rapana venosa is dioecious in sex. The ovary is composed of a number of ovarian lobules, and the testis comprises a number of ovarian lobules, and the testis comprises of gonads could be classified into 4 stages in males and 5 stages in females: 1) growing stage(in female subdivided into 2 stages of early and late growing stage). 2)mature stage. 3)spent stage or copulationstage. 4)rdcovering stage. The early growing stage in females of the purple shell was in September through February, late gorwing stage was in October to March, mature stage was in September to January, mature stage was in September to July, copulation stage was in Februaty to June and recovering stage in April to October.3. Spawning occurred 3-4 times at intervals of 1-3 days, and completed within 10 days from the beginning of spawning during the spawning season of the year.4. From the results of laboratory and field observations, egg masses are composed of a number of egg capsules, egg masses are occurred from May to late August, and in mid August depositions of egg mass in composed of 90-113 egg capsules, fecundity in an egg capsule was ranged 984 to 1,241 eggs(average 1,096 egg). Therefore, fecundity in total egg capsules spawned per individual during the spawning season is estimated as approximately 320,000 to 450,000 egges.5. The incubation period during deposition of an egg capsule to hatching larvad tood 17 days at 18.3-20.4%C(water temperature)and 1.021 (specific gravity fo sea water).

• Development and Reproduction
• /
• v.18 no.1
• /
• pp.33-41
• /
• 2014

We investigated the process of yolk absorption in Korean rose bitterling, Rhodeus uyekii, and determined the changes in its morphometric characteristics. The R. uyekii from 1 days post hatching (DPH) to 21 DPH, the eye diameter (ED) was 5.4 at 5 DPH. Thereafter, the ED/total length (TL) ratio increased to 10.7 at 21 DPH (p<0.05). The yolk length (YL) decreased from 95.4 to 1.1 by 21 DPH, and this rate of decrease was greater than that for any other dimension (p<0.05). 12 morphometric dimensions/TL for the R. uyekii were measured at each sampling day from 21 DPH to 170 DPH. At just hatching, the average TL and BW were $6.1{\pm}0.09mm$ and $4.9{\pm}0.07mg$, respectively. At 53 DPH, the average TL was $12.9{\pm}0.28mm$ and the average BW was $14.7{\pm}0.72mg$; the total length growth equation was $TL=5.507e^{0.038t}$ ($R^2=0.916$). Further, the body weight growth equation was $BW=3.3647e^{0.0296t}$ ($R^2=0.9354$). The dimensions with regard to body depth showed the greatest growth rates in the external characteristics of the fish (p<0.05). The patterns of the morphometric characteristics measured in this study can be classified in three ways. The patterns were shown to be increased (y=0.0992x+12.07, $R^2=0.8333$), decreased (y=-0.0569x+42.029, $R^2=0.8395$) or maintained (y=0.005x+18.263, $R^2=0.3678$) from 21 DPH to 170. These results will provide useful indices for the successful rearing of the R. uyekii.

• Development and Reproduction
• /
• v.18 no.4
• /
• pp.233-240
• /
• 2014

The early growth response protein 1 (Egr-1) is a widely reported zinc finger protein and a well known transcription factor encoded by the Egr-1 gene, which plays key roles in many aspects of vertebrate embryogenesis and in adult vertebrates. The Egr-1 expression is important in the formation of the gill vascular system in flounders, which develops during the post-hatching phase and is essential for survival during the juvenile period. However, the complete details of Egr-1 expression during embryo development in olive flounder are not available. We assessed the expression patterns of Egr-1 during the early development of olive flounders by using reverse transcription polymerase chain reaction (RT-PCR) analysis. Microscopic observations showed that gill filament formation corresponded with the Egr-1 expression. Thus, we showed that Egr-1 plays a vital role in angiogenesis in the gill filaments during embryogenesis. Further, Egr-1 expression was found to be strong at 5 days after hatching (DAH), in the development of the gill vascular system, and this strong expression level was maintained throughout all the development stages. Our findings have important implications with respect to the biological role of Egr-1 and evolution of the first respiratory blood vessels in the gills of olive flounder. Further studies are required to elucidate the Egr-1-mediated stress response and to decipher the functional role of Egr-1 in developmental stages.

• Journal of Aquaculture
• /
• v.11 no.4
• /
• pp.513-519
• /
• 1998

Ovulation of maturing femal mandarin fish, Siniperca scherzeri was induced using single injection of human chorionic gonadotropin (HCG) or gonadotropin releasing hormone-analogue (GnRH-a), GnRH-a plus prostaglandin F2 (PG$F_2$) or GnRH-a plus pimozide. The response was evaluated by fertilization, embryo-formation and hatching rate after insemination. Those rates were generally higher in GnRH-a group than in HCG group. The higher hatching rat of above 89% was achived using a dosage of 5,000 IU/kg HCG plus 10 ${\mu}$g/kg GnRH-a, 10${\mu}$g/kg GnRH-a plus 500 ng/kg PGF2, and 10 ug/kg GnRH-a plus 1-5 mg/kg pimozide. Ovulation was induced in all female injected with sex-maturation hormones and stimulator, but blocked in female injected with HCG plus GnRH-a plus dopamine combination, and GnRH-a plus PGF2 plus indometacin combination. These results show that the mandarin fish in spawning period secrete a sex-mutruation assosiated hormones and gonadotropin-releasing -inhibiting factor(GRIF).

• Korean journal of applied entomology
• /
• v.39 no.3
• /
• pp.193-197
• /
• 2000

Wolbachia, vertically transmitted bacterial endosymbionts, is known to induce cytoplasmic incompatibility (CI), parthenogenesis, or feminization in some insect species. The Wolbachia found to exist symbiotically as a non-virulent form in Drosophila melanogaster, however popcorn is a lethal strain of Wolbachia, which causes tissue degeneration and early death of its adult host. Popcorn-infected flies showed the delayed duration of an egg and larvae, and their pupal period and life span reduced. The oviposition and egg-hatching rate of popcorn-infected flies were decreased 15% and 80%, respectiv~ly, compared to those of the normal Wolbachia-infected flies. The pupation and emergence rates of popcorn-infected flies were 67% and 65%, respectively. When popcorn-infected flies were crossed with Wolba-chia-infected flies, and vice versa, both crosses resulted in a significant reduction in egg production, egg¬hatching, pupation, and emergence rate, and their progeny revealed the popcorn syndrome. When popcorn-infected male flies were crossed with uninfected females, popcorn was not detected in their progeny. Popcorn also maternally transmitted in flies, but it did not induce CI and affected on its host life cycle as a virulence.

• Journal of Aquaculture
• /
• v.12 no.1
• /
• pp.39-45
• /
• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.