• Korean Journal of Poultry Science
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• v.14 no.1
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• pp.39-53
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• 1987

A total of 1,440 White Leghorn pullets hatched in summer and winter, aged 20 to 72 weeks were fed 9 rations differing in dietary protein (13, 15 and 17%) and energy (2,500, 2,700 and 2,900 kcal/kg) levels for a period of 52 weeks in order to evaluate the optimum dietary energy and protein levels for laying hens. As metabolizable energy level increased from 2,500 to 2,900 kcal/kg of feed egg production, daily feed and protein intake and egg shell quality decreased, but reverse was true for the daily energy intake, energy requirement and feed cost per kg egg, body weight gain, nutrients utilizability and abdominal fat accumulation, Egg weight, viability and egg yolk Pigmentation were not affected by the dietary energy level. On the other hand, as dietary protein level increased from 13 to 17%, egg production, egg weight, daily protein intake, protein requirement per kg egg and body weight gain icreased, but daily feed and energy intake, feed and energy requirement per kg egg, egg yolk pigmentation and dry matter utilizability decreased, and no significant difference in the feed cost per kg egg, viability and egg shell quality was observed among dietary protein levels. However: the hens fed 15% and 17% Protein diets did not show significant differences in egg production, egg weight and body weight gain. For the entire laying period of 52 weeks, metabolizable energy level of 2,500 kcal/kg of feed and 15% dietary protein level were considered to be adequate to support the optimum productivity.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.975-980
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• 2004

An experiment was conducted to determine the effects of dietary supplementation of the yeast Rhodotorula glutinis(Glutinicus) on the performance and egg quality of layers. A total of 360 ISA Brown layers at 72 weeks old were assigned to one of the following 6 diets: control, 25 ppm$\beta$-carotene, 0.50%0, 1%0, 2% and 4% Glutinicus supplemented diets. Each treatment was replicated three times with 20 birds housed in 2 bird cage units. Glutinicus supplementation at the level of 0.5% significantly(p < 0.05) improved egg production and FCR Soft and broken egg production rate decreased as the level of Glutinicus supplementation increased. Eggshell strength was highest in 4 % Glutinicus supplementation. Egg yolk color increased linearly as the level of Glutinicus supplementation increased up to 2% of the diet. It was concluded that Glutinicus supplementation at the level of 0.5% can be recommended for the improvement of egg production while 2.0% can be recommended for egg yolk pigmentation.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.8.1-8.8
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• 2014

Objectives An ecofriendly alternative to chemical pesticides is bio-pesticides, which are derived from natural sources. The interest in bio-pesticides is based on the disadvantages associated with chemical pesticides. Methods We conducted acute toxicity assessments of camphor, a major component of bio-pesticides, by using Daphnia magna (D. magna) as well as assessed the morphological abnormalities that occurred in Danio rerio (D. rerio) embryos. Results The median effective concentration of camphor on D. magna after 48 hours was $395.0{\mu}M$, and the median lethal concentration on D. rerio embryos after 96 hours was $838.6{\mu}M$. The no observed effect concentration and predicted no effect concentration of camphor on D. magna, which was more sensitive than D. rerio, were calculated as $55.2{\mu}M$ and $3.95{\mu}M$, respectively. Morphological abnormalities in D. rerio embryos exposed to camphor increased over time. Coagulation, delayed hatching, yolk sac edema, pericardial edema, and pigmentation of embryos mainly appeared between 24 and 48 hours. Further, symptoms of scoliosis and head edema occurred after 72 hours. In addition, bent tails, ocular defects and collapsed symptoms of fertilized embryonic tissue were observed after 96 hours. Conclusions The camphor toxicity results suggest that continuous observations on the ecosystem are necessary to monitor toxicity in areas where biological pesticides containing camphor are sprayed.

• Applied Microscopy
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• v.42 no.1
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• pp.17-26
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• 2012

Histologic and microstructural changes during the postembryonic development of the wolf spider Arctosa kwangreungensis were studied using light and scanning electron microscopy to examine the relationship between a morphological differentiation and behavioral properties. The postembryo with abdominal yolk sac was stayed inactive in the egg case because its muscular and visual systems were not fully developed to a functional level. The first instar spiderlings, developed from the postembryo by a first molting process, started to exhibit its pigmentation on their body cuticles. In particular, undifferentiated cell clusters of central nervous system (CNS) were densely distributed within the cephalothorax, and highly differentiated abdominal ganglion was observed. They had a characteristic visual system looks more like its adult counterpart, and had segmented appendages looks more like the tiny spiders containing well oriented muscular system. After 3rd instar, spiderlings grew more rapidly with accordance to their consistent growth and periodical molting processes. Thus, the relative area of CNS with respect to cephalothorax was gradually decreased, instead a pair of venom glands, musculature, and connectives occupied the residual area. It has been revealed that the early development of spider can be controled by the feeding condition of larval period, since histologic and microstructural differentiations in both appendages and optic system were completed at the second instar. In particular, behavioral properties of the wandering spiders that depend on vision and their running ability were deeply related to physiological differentiation of the microstructural development.