• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.577-586
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• 2017

The aim of this study was to investigate the effects of fermented earthworm cast feed prepared with three complexed probiotics containing Bacillus subtilis separated from the earthworm casts, on egg production, egg quality and odor removal from poultry house. A total of 240 laying hens were divided into 4 treatments and completely randomized. Experimental groups were divided into control, 0.3 to 0.5% (fermented earthworm cast feed FECF3, FECF5) and 0.2% commercial probiotics (CP). The egg production rate was significantly higher in the FECF groups compared to the control group fed the normal feed, but there was no difference in the CP group. Haugh units, egg shell thickness, breaking strength, egg yolk index and albumen height were increased in FECF groups compared to control but not in CP group. The n-3 content of eggs was higher in the FECF groups than in the control group, while the n-6/n-3 ratio was lower and there was no difference from the CP group. Ammonia production was lower in the CP and FECF groups compared to the control group after 5 days storage at room temperature to poultry feces.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.19-24
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• 2003

Artificial spawning, larval and spat developments of the bay scallop, Argopecten irradians, which was transplanted from China on 16 August 1996, were investigated monthly until August 1997 in the Deukyang Bay, Jangheung-gun, Jeollanam-do, Korea. Sufficient amount of cultured microalgae supplemented seawater were supplied as food (6 kinds of phytoplankton) for fully grown adult individuals at 17.1-23.2$^{\circ}C$ for 44 days. A total of 45,320,000 eggs were spawned by way of 2 times of artificial spawning inductions such as exposure stimulus to the air and thermal shock (with water temperature) on 29 January and 31 January in 1997. Artificially fertilized eggs were developed to D-shaped larvae (77.5 ${\times}\;63.8\;{\mu}m)$ and metamorphosed to larvae (191.8 ${\times}\;181.2\;{\mu}m)$ 181.2 m) in the attached larval stage on the collectors. A total of 110,000 spats (average 3.04 mm in shell length) were produced at 22.8-26.3$^{\circ}C$ and 31.0-34.4 psu in the indoor rearing tank from 14 February through 7 May in 1997. In case of Argopecten irradians, if the attached larvae in the attachment stage are detached from the collector, they could not live. Accordingly, it is assumed that survival (%) of the attached larvae of A. irridians showed very low because of weak power attached to the collector due to the small number of the byssuses of the attached larva, not the short attachment period by the byssus as seen in other scallops such as Argopecten balloti.

• Journal of Aquaculture
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• v.16 no.1
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• pp.24-30
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• 2003

Studies of the seed production of Urechis unicinctus were conducted under the laboratory conditions to obtain some information for the U.unicinitus culture. The experiment included developmental studies of the egg development, larval culture, sediment preference and growth of young U.unicinctus. The experiment were conducted from March to August, 2000. The adults of U.unicinctus collected in Namhae-do, Korea. The developments of the fertilized eggs were observed under a light-microscope at intervals of one hour after containing with density of one individual per 1 $m\ell$. The larvae were fed with Phaeodactylum tricornutum cultured at the laboratory. The concentration of the phytoplankton for the feed was 30,000 cells per individual larva. With progress of development, the food concentration was gradually increased, up to 10,000 cells per individual for the young U.unicinctus. Trochophore larvae appeared on the 68 hours after hatching. On the 32 days after hatching, over 50% of fertilized eggs developed into young U.unicinctus. In order to investigate the effect of sediment on the growth and burrowing of U.unicinctus, the young worms were reared in tanks with different grain sizes. The highest value of sediment preference and survival rate of U.unicinctus was shown in the mixture sediment group with below 0.10 mm, 1.01∼12.00 mm, over 3.01 mm and shell. The lowest value in both sediment preference and survival rate of U.unicinctus was observed in 1.0l∼2.00 mm grain size.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.87-94
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• 2019

Huge amount of persimmon peels, which are byproducts usually arising after making dried persimmons from fresh persimmons, are generated in fall, every year. As the dry matter of persimmon peel contains carbohydrates over 80%, it could be a good candidate for feed. In this study, we evaluated the persimmon peel as a feed resource for a hen laying eggs. Persimmon peel has lower ratio of crude protein and fat composition while higher ratio of crude fiber composition compared to a basal laying hen feed. Feeding the persimmon peel by adding to the feed at the level of 2% or 5% did not affect the egg-laying rate from beginning to the peak of laying. In addition, feeding the persimmon peel did not affect the egg quality either, as the pH, Haugh unit, yolk color and shell thickness of the egg were not different from each other. The composition of amino acids and fatty acids were also almost same for each other, except for the linolenic acid which was slightly higher in the persimmon peel feeding groups. In conclusion, addition of persimmon peel to the feed up to 5% might be helpful to increase the income and reduce the waste produced from the agricultural byproduct.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.82-93
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• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.313-319
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• 2012

Mass production method on artificial seedling production of hard clam Meretrix petechialis was developed indoor culture system. Spawning of adult clam (SL $65.8{\pm}8.4mm$) was induced using the combined method of air exposure and water temperature raising. The fertilized eggs were developed to D-shaped larvae after 17.7 hours at $27^{\circ}C$ and hatching rate was 6.1%. Shell length (SL) of D-shaped larvae was measured to be $131.4{\pm}2.6{\mu}m$ and thereafter the larvae grew to the settled spats with SL $190.2{\pm}7.5{\mu}m$ in 4 days. Estimated survival rate of settled spats was 48.1%. Spat collection on 130,000 spats with SL $0.19{\pm}0.01mm$ performed conducted by sand bottom circulation filtering method. Collected spats grew up to $3.1{\pm}0.8mm$ in 46 days, $6.6{\pm}1.8mm$ in 87 days, and $10.5{\pm}0.9mm$ in 114 days. The relative growth between SL and shell height (SH) was calculated to be SH = 0.8501SL + 0.0196 ($R^2=0.9987$) during the whole spat period. During spats rearing, they were suffered from one time of mass mortality at SL 3.1 mm, but 51,000 spats were finally survived with the rate of 39.2% at 114 days of spat rearing in indoor tank system.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1553-1561
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• 2004

Two feeding trials were conducted with 128 pullets from 4 to 20 weeks of age and 96 laying hens from 23 to 63 weeks of age to evaluate the effects of scavenging and type of protein supplement on the feed intake and performance of improved pullets and laying hens. The experiments had a completely randomized design with four dietary treatments and four replicates. Treatments were: Control (Cont), scavenging but with access to a balanced concentrate at night; confinement (CF) and given the control feed ad libitum; scavenging and supplemented at night with the control feed, but with soybean meal replaced by cassava leaf meal (CLM); scavenging and supplemented at night with the control feed, but with fishmeal replaced y soybean meal (SBM). The mean daily dry matter (DMI), metabolizable energy (MEI) and crude protein intakes (CPI) of the pullets and laying hens, respectively, were 28%, and 18% higher for the confinement treatment (CF) compared to the scavenging treatments (p<0.001). The DMI, MEI and CPI of the pullets were not significantly different among scavenging treatments (p>0.05), but for the layers DMI, MEI and CPI were significantly higher for the CLM and SBM treatments compared to the Cont treatment (p<0.001). In the growing period, the average daily weight gain (ADG), supplement feed conversion ratio (FCR) and supplement feed cost/kg eggs (FCS) were not significantly different for CF compared to Cont, and among scavenging treatments (p>0.05). In the laying period, the hen-day production was significantly lower, and supplement FCR and FCS significantly higher for the CF compared to the scavenging treatments (p<0.001). Egg weight, and yolk, albumen and shell percentage and shape index were not significantly different among the scavenging treatments (p>0.05). However, shell and yolk percentages were significantly lower for the CF compared to the Cont treatment (p<0.01). Mortality was significantly higher for the CF compared to the scavenging treatments for pullets, and was significantly lower for the CF compared to scavenging treatments for laying hens (p<0.001). It was concluded that scavenging pullets and layers were getting around 28% and 18%, respectively, of their nutrient requirements from scavenging activities, resulting in correspondingly lower supplement feed conversion ratios and feed costs. Daily gains of the pullets were not affected by scavenging or protein supplement, but egg production and mortality were lower for the confined hens.

• Korean Journal of Poultry Science
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• v.16 no.4
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• pp.193-199
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• 1989

This study was conducted to estimate heritabilities and genetic correlations on egg compositions in Korean Native Ogol Fowl. The date analysis were a total of 58,320 eggs in 450 pullets producted from 150 dams and 20 sires of Korean Native Ogol Fowl raised at Chungnam National University from June 18. 1987 to April 6. 1989. The results obtained are summarized as follows： 1. On the egg compositions, the albumen weight at first egg, 300 and 500 days were $24.003\pm$2.499, $28.354\pm$2.755 and $31.863\pm$3.341g； the yolk weight were $10.272\pm$1.536, $16.346\pm$1.321 and $19.212\pm$1.661g： the shell weight were $3.906\pm$0.414, $4.336\pm$0.506 and $4.822\pm$0.515g, respectively. 2. The heritability estimates of egg compositions based on the valiance of sires, dams and combined components were 0.620-0.723, 0.206-0.300 and 0.413-0.511 for albumin weight；0.439-0.737, 0.484-0.544 and 0.492-0.615 for yolk weight：0.172-0.187, 0.412-0.642 and 0.390-0.503 for shell weight, respectively. 1. The genetic and phenotypic correlation coefficients of egg compositions were as follows； The coefficients between albumen weight and yolk weight were 0.089-0.654 and 0.084-0.255；between albumen weight and shell weight were 0.396-0.925 and 0.225-0.544； between yolk weight and shell weight were 0.227-0.357 and 0.098-0.358 respectively.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.45-55
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• 2001

Gametogenes, reproductive cycle, first sexual maturity(biological minimum size), sex ratio and larval development of the marsh clam Corbicula japonica were investigated monthly by histological observations. Samples were collected in brackish water of Gokgang stream, Kyungsangbuk-Do, Korea, from August 1997 to July 1998. Sexuality of Corbicula japonica is dioecious and the species are an oviparous clam. The gonads are irregularly arranged from the sub-region of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of ovarian sac which are branched arborescent. Oogonia actively proliferate along the germinal epithelium of ovarian sac, in which young oocytes are growing. The testis is composed of a number of testicular tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between developing oocytes and spermatocytes in the early developmental stages. With the further development of the ovary and testis these tissue and cells gradually disappear. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells are considered to be related to the growing of the oocytes and spermatocytes. The spawning period is from July to September, and the main spawning occur between July and August when seawater temperatures reach above 22$^{\circ}C$. The reproductive cycle of this species can be divided into five successive stages; early active (February to April), late active (May to July), ripe (June to September), partially spawned (July to September), degenerative (September to October) and resting stage (October to February). Percentages of first sexual maturity of female and male clams ranging in length from 10 mm to 12 mm are over 50% and 100% for clams over 16.0 mm in shell length. Fertilized eggs or Corbicula japonica were 80-90 ${\mu}{\textrm}{m}$ in diameter. In the early embryonic development of C. japonica, the appearance of polar body, trochophore and D-shaped veliger were observed around 40 min., 27 hours and 4 days after spawning, respectively, at a water temperature of 26.5-28.$0^{\circ}C$. The size of larvae of early umbo stage was about 185-210 ${\mu}{\textrm}{m}$ in shell length, 160-180 ${\mu}{\textrm}{m}$ in shell height around 7 days after fertilization. The correlation of relative growth between the culture day (D) and shell length (SL) was expressed by the following simple formula from D-shaped veliger to metamorphosing stage; SL = 13.300D + 209.36($r^2$= 0.9078).

• Korean Journal of Poultry Science
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• v.17 no.2
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• pp.71-78
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• 1990

This study was conducted to estimate heritabilities and genetic correlations on egg shape index and egg qualities in Korean Native Ogol fowl. The date analysis were a total of 58,320 eggs in 450 pullets bred from 150 dams and 20 sires of korean Native Ogol fowl raised at Chungnam National University from June 18, 1987 to April 6, 1989. The results obtained are summarized as follows：1. On the egg shape index and egg qualities, the egg shape index at first egg, 300 and 500 days of age were 75.044, 74.169 and 72.601 ； the shell thickness were 0.342, 0.320 and 0.326 mm： the albumen height were 6.014, 5.161 and 4.807mm：the Haugh units were 83.903, 71.348 and 71.136, respectively. 2. The heritabilities estimates of egg shape index and egg qualifies based on the varience of sires, dams and combined components were 0.120-0.827, 0.485-0.503 and 0.232-0.872 for egg shape index at first egg, 300 days and 500 days of age： 0.197-0.819. 0.184-0.756 and 0.279-0.557 for shell thickness at first egg, 300days and 500days of age：0.202-0.678, 0.119-0.394 and 0.225-0.527 for albumen height at first egg, 300 and 500 days of age 0.108-0.669, 0.237-0.251 and 0.354-0.443 for Haugh units at first egg 300days and 500days of age. 3. The genetic correlation coefficients of egg shape index and egg qualifies were as follows; between egg shape index and shell thickness, albumen height and Haugh units were 0.596-0.909, 0.384-0.943 and 0.121-0.619：between shell thickness and albumen height. Haugh units were 0.082-0.596, -0.076-0.167：between albumen height and Haugh units were 0.374-0.964.