• Journal of Forest and Environmental Science
• /
• v.13 no.1
• /
• pp.51-56
• /
• 1997

Developmental characteristics and reproductive ability of Caloglyphus sp. were examined under the constant temperature conditions. This mites has five stages ; egg, larva, protonymph, deutonymph and adult. All active instars preyed on larvae of pine gall midge, Thecodiplosis japonensis Uchida et Inouye. The developmental period from the egg to the adult decreased with temperature increase at a range between $15^{\circ}C$ and $30^{\circ}C$. The threshold of temperature and the thermal constant for the development from the egg to the adult were $8.2^{\circ}C$ and 122.0 day-degrees, respectively. At $25^{\circ}C$, survival rate from egg to deutonymph was estimated as 66.4%, and longevity of the adult was 12.3 days for male and 10.0 days for female. After a preoviposition period of 1 and 2 days female laid an average of 360.6 eggs each, almost all during the first half of their life time. The value of the net reproduction(Ro), the mean length of a generation(T) and the intrinsic rate of natural increase($r_m$) were calculated as 101.1, 9.3 days and 0.494 per female per day, respectively.

• Journal of Sericultural and Entomological Science
• /
• v.50 no.2
• /
• pp.126-132
• /
• 2012

Two different feed(bran and swine feed) effect was tested on development of Tenebrio molitor at $25{\pm}5^{\circ}C$, $65{\pm}10%RH$. There was no significant feed effect on larval developmental periods(80.0 ~ 83.7 days), pupal length (18.1 ~ 18.7 mm) and fecundity(44.3 ~ 55.3 eggs) during first two days. However, fecundity was significantly affected by the pupal weight(P < 0.05), such that the number of eggs 172.3, 191.2, 215.0 gradually increased as pupal weight rose from 0.12 g, 0.15 g to 0.18 g, respectively. During the first two weeks of oviposition was 51.8%, which gradually decreased for further days. Longevity was $27.1{\pm}6.9$, $30.1{\pm}7.8$, $27.4{\pm}8.5$ days with increasing pupal weight of 0.12, 0.15, 0.18 g, respectively. Larval densities of 100, 300, 500 and 700 individuals reared in the container ($16{\times}21.5{\times}7cm$) resulted 67.9% of the T. molitor pupation during first three weeks. Pupal weight was decreased $146.9{\pm}6.5$, $142.1{\pm}8.3$, $122.0{\pm}9.6$, $118.5{\pm}5.2mg$ when it was reared at different larval densities of 100, 300, 500 and 700 individuals, respectively in size of($16{\times}21.5{\times}7cm$) rearing container.

• Korean Journal of Ichthyology
• /
• v.21 no.4
• /
• pp.239-246
• /
• 2009

To establish a database for artificial seed production of stone flounder Kareius bicoloratus, experiments were conducted to study the characteristics of spawning and fecundity of this species. Broodstocks were captured in the area of Gyeokryeolbiyeoldo, Chungnam, Korea in October 2003 and induced to natural spawning. The broodstock consisted of 12 females (34.5~51.0 cm total length and 540~2,200 g body weight) and 23 males (29.0~38.0 cm total length and 310~680 g body weight). Gonad development began in December and proceeded in the direction of the tail; measurements were made with the naked eye. The tank-held broodstock were reared for 3 months before spawning, which continued for 77 days from January 9 to March 27, 2004. Daylength during the spawning was recorded at the yearly shortest of 9.8~12.1 hours and the water temperature was maintained at $8.4{\sim}12.2^{\circ}C$. The total fecundity was 19,844,000 individuals, among which 15,433,000 individuals (77.8%) were produced during the mid-spawning period. The average bloating rate, egg-fertilization rate and hatching rate of the total number spawned reached 50.4%, 58.5% and 55.6%, respectively, and 93.8% of the hatched fry appeared normal. The number of total eggs in absolute fecundity per total length was proportional to both lengths, as was the number of total eggs in relative fecundity per total length. The number of total eggs in absolute fecundity per body weight was proportional to body weight as was the number in relative fecundity per body weight except that the number in relative fecundity per gram decreased after a peak in increased body weight at a certain point.

• Korean Journal of Poultry Science
• /
• v.30 no.3
• /
• pp.161-167
• /
• 2003

A study was conducted to investigate the effect of supplementing earthworm meal (EWM) on the performance of laying hens and fatty acid composition in egg yolks. A total of 360 laying hens at 55 weeks of age were fed the experimental diets containing 0.0% (Control), 0.1% and 0.2% of EWM for 5 weeks. Eggs were collected and weighted every day and egg production and feed conversion were recorded every weeks during the experimental period. However fatty acid composition of egg yolk were measured at last week of experimental period. Amount of feed intake tended to increase by supplemental EMW, but feed conversion ratio of birds fed EWM was not different among three groups. Average egg production seemed to increase and significantly improved (P<0.05) when fed a 0.1% EWM and 0.2% EWM, respectively. Average egg weight was prone to decrease when fed a 0.1% EWM compared to that fed a 0% (control) or 0.2% EWM. Average daily egg mass tended to improve by the addition of EWM. It was more increased in 0.2% EWM treatment than 0.1% EWM. The ratio of egg yolk n-6/ n-3 fatty acids contents was 5:1 fed a 0.1% and 0.2% EWM. But these ratio was 10:1 in control group. It is concluded that 0.2% earthworm meal supplementation in the 55 weeks old laying hens diet, improves the laying performance and ratio of egg yolk n-6/ n-3 fatty acids contents (P<0.05).

• Korean Journal of Poultry Science
• /
• v.13 no.1
• /
• pp.23-30
• /
• 1986

The Calorimetric experiment was made firstly to measure the difference in energy metabolisms of laying hens among their three different laying periods, secondly to estimate the energy requirements of the layers on their respective laying periods. The laying period was divided into three chronological periods of 25-40, 41-55, and 56-69 weeks old of laying hens, which are refered to as period I, II, and III respectively. 1) The fasting heat production (FHP) of laying hen on the three laying periods were 81.5 Kcal/kg$\^$0.75/ for period I, 72.3 Kcal/kg$\^$0.75/ for perod II, and 97.5 Kcal/kg$\^$0.75/ for perod III. The marked increase in FHP was found in period m, while there was a small difference in FHP between period I and II. The present study have observed among the birds in period in the high degree of plumage defectiveness, and this condition of bird might have accounted for the increase in FHP. 2) The regression equation between ME intake and energy retention (ER) were calculated, and the equations indicated that, for the period I, II, and III, the ME requirements for maintenance (MEm) were 123, 111, and 131 Kcal/kg$\^$0.75/ respectively, and that the Net Availabilities of Metabolizable energy (NAME) were 76, 79, and 74 percent respectively. For the whole laying period measured, MEm was 119 Kcal/kg$\^$0.75/ and NAME was 79 percent. There was a tendancy of higher MEm, and lower NAME during Period III, comparing with period I and II.

• Korean Journal of Poultry Science
• /
• v.31 no.3
• /
• pp.177-185
• /
• 2004

This experiment was conducted to examine the dietary effects of local granular ark shell(GAS) replacing limestone on egg shell quality in aged hens. A total of 200 Hy-Line Brown layers of 54-weeks-old were allotted into four treatments with five replications each. They were fed control(limestone only) 1% GAS, 2% GAS and 3% GAS diets for 6 weeks. GAS was substituted for coarse-type limestone at 0, 1, 2 or 3% of diet on weight basis. Particle sizes of limestone and GAS were within the ranges of 2~4 mm in diameters. In vitro HCl solubility of GAS was significantly lower(6.27 vs. 7.90%) compared to that of limestone(p < 0.05). The dietary treatment did not affect feed intake and egg production rate of the birds. Egg shell strength and thickness tended to be improved for birds fed the diets containing higher levels of GAS. The average egg shell strength and thickness of 2 or 3% GAS groups were significantly greater than those of the control (P < 0.05). The Tibial ash content of birds from 3% GAS group increased significantly as compared to that of the control. Tibial breaking strength, however, was not affected by the dietary treatment. Serum Ca and P contents of the birds were also not different among the dietary treatments. In conclusion, locally prepared GAS can be used as a calcium source in aged layer diet.

• Korean Journal of Poultry Science
• /
• v.30 no.2
• /
• pp.107-112
• /
• 2003

This experiment was conducted to study the optimum energy feeding system for broiler breeders peaked in summer season with 400 caged hens of Ross strain. Four of energy supply series which were different in daily energy allotment during laying period were employed for 40 weeks from 24 to 64 weeks of age. All experimental diets were formulated to contain 2,750 kcal ME/kg with adjustments made in total feed allotment to provide the desired energy levels. Total consumption of the feed would provide 20 grams of protein, 4 grams of calcium and 0.35 grams of available phosphorus. There were no significant difference in hen-day egg production and average egg weight among the series of energy supply, but egg production showed a trend to decline as the level of energy allotment increased. Feed, ME and CP conversion and feed cost required per egg or per kg egg were significantly increased as the level of energy allotment increased(p<0.05). It was concluded that the Treatment 1, which supplied 280kcal ME per day at the age of 24 weeks and then increased the energy supply up to 400kcal ME per day at the peak period of 30∼34 weeks of age, was superior in all production parameters.

• Korean Journal of Ichthyology
• /
• v.32 no.1
• /
• pp.14-20
• /
• 2020

The purpose of this study is to clarify when spawning occurs of Clupea pallasii in the coastal waters of Jinhae Bay and Yeongun-ri, Tongyeong, Korea from December to February using SCUBA observation which is known as spawning season. Eighteen surveys of SCUBA diving observations have performed at 3 stations of Jinhae Bay from December 2017 to January 2018 and 24 times of survey at Yeongun-ri, Tongyeong from December 2017 to February 2018. In Jinhae Bay, average 740,274 eggs/㎡ fertilized eggs were observed in Judo Island and average 671,718 eggs/㎡ were observed in Gusan-myeon. On December 30, 2017, about 388,444 eggs/㎡ fertilized eggs were observed in Yeongun-ri, Tongyeong but no eggs were founded in next surveys. The results in this study suggest that spawning season of C. pallasii in the coastal waters of Jinhae Bay and Tongyeong begins in late December at average 7.7℃ water temperature.

• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.189-197
• /
• 2022

This study was conducted to compare the egg productivity, egg quality, and blood characteristics of laying hens with different laying rates, and the frequency and cumulative duration of the sitting behavior observed before laying was investigated. Twelve 45-week-old Hy-Line Brown laying hens were randomly assigned to two treatment groups with three replicates. Treatment groups were classified as layers laying over 80%(high egg performance layers; HEP) and layers laying below 50%(poor egg performance layers; PEP). The experiment lasted 4 weeks. HEP showed higher hen-house egg production ratio and egg mass and lower feed conversion ratio(FCR) (P<0.05) compared with PEP, although egg weight was higher in PEP (P<0.05). In terms of egg quality, PEP showed differences in eggshell quality (eggshell color, eggshell thickness, and eggshell weight) (P<0.05). Additionally, HEP showed high triglycerides(TG), and PEP showed high alanine transaminase(ALT) level (P<0.05) in serum collected in the morning. In the afternoon, the HEP showed higher lactate dehydrogenase(LDH) levels (P<0.05). No differences in the Ca: P ratio were observed between layers with different laying rates. One hour before egg laying, HEP exhibited sitting behavior 4 times on average, each lasting 25 minutes. In conclusion, egg production and quality differ between HEP and PEP, and HEP showed frequent sitting behavior before egg laying. However, additional research is necessary to explore approaches other than specific behavioral observation to distinguish poor layers in the flock for application in farms.

• Korean journal of applied entomology
• /
• v.55 no.4
• /
• pp.421-429
• /
• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.