• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.369-376
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• 2003

This experiment was conducted to investigate the influence of different levels of metabolizable energy (ME) and crude protein (CP) on post-molt performance and egg quality of spent laying hens. Four hundred and thirty two, ISA Brown hens at sixty six weeks of age after molt induction were fed six experimental diets containing three ME (2,750, 2,800, 2,850 kcal/kg) with two CP (15, 17%) levels in a factorial design. The influence of ME and CP were evaluated on egg production, egg weight and feed intake throughout 24 weeks of production. Egg mass and feed conversion ratio (FCR) were measured during the experimental period. Haugh unit, yolk color and eggshell breaking strength were measured at 5%, 50%, peak, post peak and end stage of egg production. The hens fed 2800 kcal/kg diet along with 15% CP recorded the highest outcome of egg production (P<0.05). The egg weight has been shown to increase with hens receiving 2,800 kcal/kg ME. Daily egg mass tended to increase in hens fed with 15% CP and 2,800 kcal/kg ME. Feed intake decreased significantly with the level of ME and CP in the diet increased (P<0.05). Yolk color was improved significantly in eggs laid by the hens receiving 17% CP than 15% diet. It also tended to be higher in 17% CP with 2,800 or 2,850 kcal/kg ME diet treatments. Egg shell breaking strength increased with hens receiving diets of 15% CP and 2,800 kcal/kg. From this experiment it can be concluded that the ME level of 2,800 kcal/kg coupled with 15% CP could be used to achieve the higher egg production and better eggshell strength in induced molting hens.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.129-135
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• 2007

Ecdysteroids are known as insect molting hormone. At the same time, ecdysteroids and plant ecdysteroids (phytoecdysteorids) reveal beneficial effects on mammal. The present study was undertaken to determine the possible cellular mechanism of action of phytoecdysteroids in bone metabolism. The effects on the osteoblasts were determined by measuring cell proliferation, alkaline phosphatase (ALP) activity, and gelatinase activity. The effects on the osteoclasts were investigated by measuring tartrate-resistant acid phosphatase (TRAP)(+) multinucleated cells (MNCs) formation after culturing osteoclast precursors. Phytoecdysteroid treatment showed a increase in ALP activity of osteoblasts. Phytoecdysteroid increased the activity of gelatinase. In addition, phytoecdysteroid decreased the osteoclast generation induced by macrophage-colony stimulating factor (M-CSF) and receptor activator of NF-kB ligand (RANKL) in (M-CSF)-dependent bone marrow macrophage (MDBM) cell cultures. Taken these results, phytoecdysteroid may be a regulatory protein within the bone marrow microenvironment.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.73-77
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• 2013

Silkworm transgenesis scientists have done some genetic modification work on multivoltine silkworms, but that type of silkworms is less commercial feasible. They are easy to manipulate, because they breed all year round. But the commercial silkworm variety must undergo hydrochloric acid treatment at a high temperature to be artificially hatched. Hydrochloric acid penetrates through the holes in the silkworm eggs, fatally damaging their reproduction. So it had been thought that altering the properties of the commercial silkworm variety would be very difficult. So we have tried to make from diapause to non-diapause eggs using diapauses varieties, 'Backokjam' and 'Jam 124'. At present, our group has establishing the conditions for non-diapause eggs. Oviposited eggs after 40 ~ 60 hours were incubated for 24 hours at $15{\sim}20^{\circ}C$ with dark condition. Non-diapause eggs were completely induced. The hatching rate, molting rate and pupation rate of non-diapause 'Jam 124' and 'Backokjam' eggs showed no differences compared to diapause eggs. When transgenic silkworm using the non-diapause eggs, the hatching rate showed that non-diapause eggs induced from diapause were 40 ~ 70%, diapause eggs treated with artificial incubation were 10 ~ 30%, and polyvoltine strains, HM eggs were 30 ~ 50%. Therefore, we suggest that modification techniques of the commercial silkworm eggs adequate for silkworm transgenesis can be used to develop transgenic silkworms more easily.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.185-202
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• 2020

The diapause induction season in Ostrinia furnacalis (Lepidoptera: Crambidae) was estimated in Suwon. Three batches of adult generations were observed, the first one from early May to early July, the second from early or mid-July to early or mid-August, and the third from mid-August to October. In outdoor larval rearing, colony rearing occurring from mid-July to mid-August produced both non-overwintering and overwintering larvae, whereas late-reared colonies produced only overwintering larvae. Larvae collected during July and August in maize fields produced both non-overwintering and overwintering larvae, whereas late-collected larvae produced only overwintering larvae. The results indicated that O. furnacalis has a bi- or trivoltine complex life cycle in this area. In the laboratory, when larvae of all instars within 9 h after molting were first treated to a diapause induction condition (11:13 h = light:dark photoperiod and 20℃), almost all larvae were induced to diapause. However, when similar treatments were conducted age-specifically for the 5th instar larvae, diapause induction rates in 3- and 4-day-old larvae of the 5th instar decreased. In contrast, when larvae were subjected to the diapause induction treatment only during the periods from the hatching stage to the 2nd, 3rd, and 4th instar, almost all larvae were not induced to diapause. The results suggest that the early age of the 5th larval instar is the last stage for sensitivity to diapause induction stimuli. In the diapause-induced larvae, hemolymph trehalose content increased and body supercooling points dropped, compared with those in non-diapause larvae.

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.219-228
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• 2003

Two experiments were conducted to investigate the feeding value of stevia by-product (SB) on performance in broiler chicks and laying hens. In experiment 1, a total 256 one day old male broiler chicks were replaced in 0, 2, 4, 7% of SB with four replicates for 5 weeks. All diets were consisted of isocaloric and isonitrogen containing CP 21.5, 19% and ME 3,100 kcal/kg for starting and finishing period, respectively. Weight gain of SB treatments decreased compared with control for the first three weeks, but no difference for the finishing period. Feed intake and feed conversion were no statistical difference between control and feeding stevia groups for overall period. There were no different total number of intestinal microflora. However, the number of Salmonella and E. coli of cecum seemed to decrease in SB feeding groups. Total Lactobacillus and yeast tended to be higher in those groups than control. The PUFa increased in SB treatments, but was no significance. In experiment 2. stevia by-product(SB) were mixed with iso-caloric and isonitrogeneous method to investigate the feeding value in induced molting hens of 78 weeks old. A total 360 birds were replaced in the four treatments(0, 2, 4, 8% SB) with five replicates. Egg production, quality and fatty acid composition in egg were periodically measured for 20 weeks. No difference were found in egg production, feed intake, feed conversion between control and SB treatments for overall period. Egg shell breaking strength, thickness, albumen height and Haugh unit were not statistically different. However, yolk color was significantly high in SB treatments compared to control(P<0.05). Yolk MUFA increased significantly in SB treatments compared to that of control(p<0.05), but PUFA tended to decrease in SB treatments. No significant difference was detected in total sugar in egg yolk between SB treatments and control. Tocopherol of egg yolk 2 and 4% SB were significantly higher than those feed the control (p<0.05).