• Korean Journal of Poultry Science
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• v.18 no.2
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• pp.67-84
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• 1991

The purpose of this study was to investigate the effects of dietary protein levels on laying hen performance. The level of methionine and lysine were 0.32% and 0.64%, respectively and the levels of protein were 12%, 13%, 14% or 15%. Total 384 laying pullets of 22weeks age were reared from January 28, 1989 to March 23, 1990 for 60 weeks. The results obtained were summarized as follows : 1 Egg productions was highest at 15% of protein in phase I, 14% in phase II, and 13% in phase III, and there was significantly different egg Production among treatments during phase I and phase II (P＜0.05). 2. Egg weight was heaviest in 14% of protein treatment in three phases and they showed significantly different egg weight among different levels of protein in phase I (P＜0.01), phase II and III (P＜0.05) , but there was not significantly different between 14% and 15% of protein. 3. Daily egg mass tends to increase followed by increasing of protein level and showed signifiant differences among treatments in phase I and phase II (P＜0.01). 4. The 14% of protein treatment showed the highest daily feed intake and it showed significant difference in phase I and phase II (P＜0.01) , but there was no significant difference between 14% and 15% of protein. 5. Feed efficiency was improved significantly followed by increasing of protein level in phase I (P＜0.01) and phase II (P＜0.05), but there was no significant difference among treatments in phase III. 6. Viability tends to increase as increasing of protein level, but there was no significant difference among treatments. 7. Utilizabilities of dry matter, crude protein and ether extract of experimental diets were not different among treatments, but the utilizability of carbohydrate tends to increase as increasing of protein level (P＜0.05). 8. Eviscerated yield and abdominal fat accumulation was not difference among treatments. 9. Egg shell quality and chemical composition of egg content were not different among treatments. 10. The feed cost per kg egg mass showed the cheapest in 13% of protein treatment in all phase, but there were no significant differences among treatments.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.139-147
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• 1989

An experiment was carried out to investigate the effects of dietary energy levels and protein feeding systems on the performance of laying hens. Total 960 White Leghorn pullets were alloted in 10 treatments consisted of 1 metabolizable energy levels (2,900 and 2,600 kcal/kg) and 5 protein feeding systems (17-17-15%, 17-15-13%, 15-15-15%15-15-13% and 15-13-13% in phase I, II and/or III, respectively) from 20 to 80 weeks or age. As metabolizable energy level increased from 2,600 to 2.900 kcal/kg of diet, e99 Productions in phase I and II were not different but decreased in phase III. Egg weight was not different, but daily feed intake and viability were decreased in phase I, II and III. Feed conversions in phase I and II were improved but in phase III it was not different. On the other hand, as dietary Protein level increased from 13 to 17%, egg production and egg weight were increased, and feed conversion was improved , but daily feed intake and viability were not affected by the dietary protein level. For the laying period of 60 weeks, metabolizable energy level of 2,600 kcal/kg of diet and 17, 15 and 13% dietary protein levels in phase I, II and III, respectively, were considered to be adequate to support the optimum productivity.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.299-306
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• 2004

The objective of this study was to investigate the influence of egg storage, broiler breeder age, and the change of egg weight during incubation on growth rate of chicks and 43-day-old dressing percentage. The trials involved hatching eggs obtained from 27-wk-old hens and stored for 6 d for the Young-EXP group, from 28-wk-old hens and stored for 0 d for the Young-CON group, from 51-wk-old hens and stored for 6 d for the Old-EXP group, and from 52-wk-old hens and stored for 0 d for the Old-CON group, The hens were two commercial broiler breeder flocks of the same strain (Cobb) but of different egg producing stages(early and middle stages of egg production). The chicks were grown on floor pens for 6 wks, The differences of setting egg weights between Old-CON and Old-EXP groups were 1 g, but those between Young-CON and Young-EXP groups were 2.9 g(P<0,05). The loss of egg weight during 18 d incubation did not greatly differ among four groups, but the loss of egg weight during 21 d incubation was significantly (P<0.05) more in the middle stage of egg production groups than in the early stage of egg production groups. The mean birth weights of the middle stage of egg production groups were significantly(P<0,05) heavier by 8,7 g than those of the early stage of egg production groups; however, the differences of 6-wk-old body weight were not significant between egg producing stages. The differences of body weights in both egg producing stages were not significantly influenced by egg storage period in overall wks of ages. Egg storage and hen age did not greatly influence to the 43 d dressing percentages, either, The correlations of the setting egg weight with 18 d egg weight during incubation, growth rate of chicks, or 43 d dressing percentage were not significant.

• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.173-179
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• 2011

This experiment was conducted to evaluate the dietary effects of multiple mixture of probiotics on laying performance and the faecal examination in laying hens (Hy-line Brown) at the early (21~40 wk) and middle (41~65 wk) laying term. Multiple probiotics were produced by developing products and the properties of microorganisms were examined for detecting of acid-resistance, bile salt-resistance and antibacterial activity against pathogenic enteric bacteria. Probiotics produced to the fermenting cultures of four selected organisms and soybean meal substrates by nine steps of NK proliferating system. The most microorganisms were shown higher resistance of acidity and bile salt. High antibacterial activities against Bacillus subtilis, Lactobacillus plantarum and Enterococcus faecium were observed, but was not against Saccharomyces cerevisiae. Total egg production of the treatment was significantly higher than control group but was not statistically different between 0.1% and 0.2% treatments (P>0.05). Average egg weight of the treatment in early laying term was also significantly higher than control but was not significantly different between 0.1% and 0.2% treatments (P>0.05). But the egg weight of the treatment in middle laying term was significantly higher than control and between 0.1% and 0.2% treatments (P>0.05). The mortality of 0.2% treatment was significantly lower than control (P<0.05), and 0.2% treatment in the early laying term was tended to decreased than 0.1% treatment and control. But there was not significantly between 0.1% and 0.2% treatments in middle laying term. In feed intake, 0.2% treatment in middle laying term was significantly increased than control and 0.1% treatment (P<0.05) but not in early laying term. In faecal examination, the total number of Lactobacillus of 0.1% treatment was significantly increased than control in whole laying term (P<0.05), but Coli form of the treatment was decreased than control in middle laying term. In conclusion, dietary long term supplementation of multiple probiotics improved performance of lay hens, egg weight and mortality drop by regulating enteric bacteria.

• Journal of Aquaculture
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• v.4 no.2
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• pp.85-95
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• 1991

Spawning inducement of flounder, Paralichthys olivaceus, was attemped by the control of water temperature and photoperiod from June 1, 1989 through January 5, 1990 (189 days) Water temperature was gradually decreased from $21.7^{\circ}C$ to $10.6^{\circ}C$ which was the minim biological temperature for spawning of flounder. Water temperature was increased asain to $15^{\circ}C$ gradually, and then maintained at this level through the end of spawning. Photoperiod was also changed gradually from 10L/14D in June 1, 1989 to 14L/10D in July 25, 1989. Spawning of the fish occurred from October 4, 1989 through January 5, 1990 (93 days). The average number of eggs spawned during the spawning season per female were 2.67 billion. The first spawning occurred on the 60th day after the time of minimun water temperature $10.6^{\circ}C$. The water temperature and photoperiod at the first spawning were $13^{\circ}C$ and 14L/10D respectively It took 71 days to spawn since the photoperiod had changed from 10L/14D to 14L/10D. Spawning period can be devided into three terms. The first term was continued for 30 days from the beginning of the spawning. The second term for 41 days was the major spawning period followed by the third term, the final period of the spawning, for 22 days. The percentage of average fertilization rate of the eggs in the first, second and third spawning terms were $37.4{\%},\;54.1\%\;and\;19.6\%$, respectively. Feeding rate was increased in the maturing period but, decreased in the spawing period. During the final spawning period, the abrubt decreasing of the feeding occurred again.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.85-94
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• 2001

Spawning, hatching, survival and cannibalism of the octopus, Octopus ocellatus, were investigated at the indoor laboratory. The specimens were collected in the coastal waters of Puan, Korea, from March 2000 to May 2001. Changes in the gonadosomatic index (GSI) during March to May, 2000 were similar to those in 2001. The GSI began to increase in March and reached the maximum in May 2000 and 2001. The mean fecundity of adult individuals in April was larger than those in March and May in 2000 and 2001. In the investigations of survival rates of adults according to the water layers, the mean survival rate in the middle water layer was higher than that in the bottom layer in year 2000 (p = 0.002). The survival rate during 2001 was similar to the result of year 2000 in the water layers (p = 0.018). From the investigations with the purchase dates, the survival (88.8%) in the early spawning period (April 10, 2000) showed larger than those in the mid-spawning (May 11, 2000) and the late spawning (May 23, 2000). For aquaculture, it is suggested that the purchase timing of adults in the early spawning period will have a better result than that of the other spawning periods. In the amount of spawning with water layers, the number of eggs spawned of the adults in the middle layer were larger than those in the bottom layer. In the number of eggs spawned with the purchase dates, the number of eggs spawned in the early spawning period were larger than those in the middle and late spawning periods. The size of eggs spawned were 6.904$\times$2.520 mm. the hatching period required (from spawning to hatched larvae) was 55 days (April 17 to June 7,2000) at water temperatures of 11.2 to 21.1$^{\circ}C$. In case of the hatching rates with water layers, the hatching rate in the middle water layer was larger than that in the bottom one (p = 0.004).

• Korean Journal of Poultry Science
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• v.18 no.1
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• pp.9-31
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• 1991

The purpose of this study was to investigate the effects of dietary methionine and lysine levels on laying hen performance. The level of protein was fixed 15% during whole experiment period, but the levels of methionine and lysine were 0.30% and 0.58% (Low), 0.32% and 0.64% (Medium), 0.35% and 0 70% (High), respectively. Total 288 laying pullets of 22 weeks age were reared from January 28, 1989 to March 23, 1990 for 60weeks. The results obtained were summarized as follows : 1. The e99 Productions were highest in medium treatment in phase I (22~42weeks of age), phase II (42~62 weeks of age) and phase III (62~82weeks of age) and especially, there was significant difference among treatments during phase II (P＜0.05). 2. Egg weight was significantly increased as the levels of methionine and lysine were increased up to methionine and lysine were 0.32% and 0.64%, respectively(P＜0.01). 3. Daily egg mass was highest when the levels of methionine and lysine were 0.32% and 0.64%, respectively and there were significant differences among treatments during phase I and phase II (P＜0.01) 4. Daily feed intake was increased as the levels of methionine and lysine were increased, and there was significant difference among treatments during phase III (P＜0.05). 5. Feed efficiency was best in medium treatment in phase I and phase II (P＜0.01) 6, Viability was highest in medium treatment, but there was no significant difference among treatments. 7. Nutrient utilizability of experimental diets was not significantly different among treatments. 8. Eviscerated yield was highest and abdominal fat accumulation was lowest in medium treatment, but there was no significant difference among treatments. 9. Egg shell quality and chemical composition of egg content were not different among treatments. 10. The feed cost per kg egg mass was lowest in medium treatment and there were significant differences among treatments in phase I, phase II and whole egg laying period(P＜0.05)

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.177-183
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• 1998

A feeding trial was conducted to investigate the performance of various Korean Native Chickens (KNC) for 64 weeks. Eight hundreds and ten KNC one-day birds were arranged to three strains, Dark Brown(D), Light Brown(L) and Black(B). Each strain had three replicates of 90 birds a replicate. Birds fed same diet with Korean standard feeding. Data were obtained growing performance to 20 week of age and laying performance from twenty one to sixty four week. During the growing stage from hatch to 20 week of age, there were not significant difference to three strains on viability, body weight and feed intake. L strain tended to be earlier 50％ egg production day than that of other strains, but was not significantly different. Egg production of L strain was the highest of strains. It showed significantly higher egg production compared to that of D strain(P<0.05), but was not statistically different from that of B strain. Laying peak period was between 28 to 32 week of age in all strains, Egg weight was heavier in D strain(P<0.05). Feed intake was the same as 105g, and feed conversion improved in L strain(P<0.05). There were not difference on interior egg and eggshell quality by strains although eggshell thickness improved slightly in D strain. Fertility of D strain was the highest compared to others(P<0.05) regardless laying stages. Hatchability was not influenced by strains at 39 weeks old, but was significantly higher in B strain at 62 week of age(P< 0.05). The results of this experiment indicated that KNC 3 strains were not effect on egg production, feed intake and feed conversion ratio.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.217-222
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• 2013

This work was carried out to investigate the performance of large-type Korean native ducks at middle laying phase (30 to 50 weeks). A total of one hundred and sixty eight laying ducks were divided into A and B strains (6 replications/strain, 14 birds/replication and fed practical diet, for 20 weeks). There was no significant difference in body weight, daily feed intake and average egg weight. With increasing rearing period, mean body weight tended to be decreased and showed the lowest value (2,649 g) at 42 weeks of age (P<0.05). Similar trend was observed for weekly feed intake and average egg weight which decreased with passing weeks and was lowest (190.5 g and 83.8 g, respectively) at the age of 42~46 weeks (P<0.05). Daily egg production of B strain was higher than that of A strain at the age of 46~50 weeks (P<0.05). Weekly egg production of A and B strains commenced to decrease from the age of 42 weeks, however, B strain recovered at 46~50 weeks of age (P<0.05). At the age of 30~38 weeks, the egg production in B strain was higher than A strain (P<0.05), whereas, there was no significant difference between both the strains during 38~50 week. Feed conversion ratio of A strain was higher than that of B strain at 46~50 weeks of age (P<0.05). Weekly feed conversion was highest at the age of 42~46 weeks (P<0.05). In conclusion, the present results provides the basic information of the performance record of large-type Korean native ducks for the middle laying phase.