• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.1-12
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• 2005

Feed conversion efficiency contributes directly or indirectly on the cost benefit ratio of silkworm rearing and is considered to be an important physiological criterion for evaluating the superiority of silkworm breeds/hybrids. Food intake, assimilation and conversion of indigenous as well as exotic silkworm races are well studied by many researchers. In this review, an attempt has been made to consolidate works on feed conversion aspects of indigenous and exotic silkworm races. The paper also deals with the effect of various factors viz., nutritional, environmental and feeding on food assimilation and conversion parameters of mulberry silkworm.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.2
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• pp.171-174
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• 2012

In order to study the feasibility of utilizing bivoltine foundation cross (FC2) males of the silkworm as male components with Pure Mysore (PM), six foundation crosses viz,CSR2 x CSR27, CSR27 x CSR2, CSR27 x CSR50, CSR50 x CSR27, CSR2 x CSR50 and CSR50 x CSR2 along with CSR2 pure breed were assessed for performance of parental crop,grainage, rearing and reeling performance. The foundation crosses exhibited better performance than CSR2 as a parental crop and male component which resulted in higher egg recovery. Though there was not much difference between PM crossed with FC2 and CSR2 males pertaining to important bioassay parameters, PM x CSR2 exhibited superiority in reeling traits particularly with reelability and raw silk %. This study reveals that FC2 seed cocoons can be utilized during exigency when there is a dearth for CSR2 seed cocoons but not regularly.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.201-202
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• 2003

Recently, probiotics is applied for aquaculture management as an alternative method of antibiotics. Probiotics is defined as a live microbial feed supplement which a good effect to the host animal by improving its microbial condition of gastrointestinal tract (Fuller, 1989). Generally, probiotics affect growth and survival of cultured fish, water quality, immune system and so on (Rengpipat et al, 2000, Robertson et al, 2000). (omitted)

• Journal of Life Science
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• v.29 no.9
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• pp.996-1001
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• 2019

Edible insects are reported to be rich in protein, minerals and vitamins, and much attention has been paid to them as a future food source. In Korea, they were massively reared and sold. In order to enhance the market value of edible insects for industrialized mass production, it is important to develop the safe and nutritious feed sources for rearing them are needed. In this study, a chlorella-free control feed (Exp1) and six experimental feeds supplemented with 0.5~2.0% liquid or powder types of chlorella were formulated. Protaetia brevitarsis and Allomyrina dichotoma, registered as food ingredients in Korea, were fed with the designed feeds and parameters of growth including larval survivorship, larval body weight, and larval period were analyzed. When chlorella added, larval survivorship was increased 2~13%(p>0.05) and 9~22%(p<0.05) in each beetle compared to the control. Interestingly, the larval period of chlorella powder-added groups was shortened by 24 days (Exp3, p<0.05) in P. brevitarsis and 19 days (Exp4, p<0.01) in A. dichotoma. Meanwhile, some parameters, crude protein, crude fiber, copper, zinc, potassium, magnesium, and phosphorous, in chlorella-added groups of P. brevitarsis were also higher than the control group. Therefore, chlorella could promote the larval growth performance of these two beetles and be used as a feed additive in rearing them.

• Animal Bioscience
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• v.35 no.2
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• pp.224-235
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• 2022

Objective: Cage rearing has critical implications for the laying duck industry because it is convenient for feeding and management. However, caging stress is a type of chronic stress that induces maladaptation. Environmental stress responses have been extensively studied, but no detailed information is available about the comprehensive changes in plasma metabolites at different stages of caging stress in ducks. We designed this experiment to analyze the effects of caging stress on performance parameters and oxidative stress indexes in ducks. Methods: Liquid chromatography tandem mass spectrometry (LC/MS-MS) was used to determine the changes in metabolites in duck plasma at 5 (CR5), 10 (CR10), and 15 (CR15) days after cage rearing and traditional breeding (TB). The associated pathways of differentially altered metabolites were analyzed using Kyoto encyclopedia of genes and genomes (KEGG) database. Results: The results of this study indicate that caging stress decreased performance parameters, and the plasma total superoxide dismutase levels were increased in the CR10 group compared with the other groups. In addition, 1,431 metabolites were detected. Compared with the TB group, 134, 381, and 190 differentially produced metabolites were identified in the CR5, CR10, and CR15 groups, respectively. The results of principal component analysis (PCA) show that the selected components sufficiently distinguish the TB group and CR10 group. KEGG analysis results revealed that the differentially altered metabolites in duck plasma from the CR5 and TB groups were mainly associated with ovarian steroidogenesis, biosynthesis of unsaturated fatty acids, and phenylalanine metabolism. Conclusion: In this study, the production performance, blood indexes, number of metabolites and PCA were compared to determine effect of the caging stress stage on ducks. We inferred from the experimental results that caging-stressed ducks were in the sensitive phase in the first 5 days after caging, caging for approximately 10 days was an important transition phase, and then the duck continually adapted.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.408-415
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• 2013

The objective of this experiment was to assess the use of different vitamin D metabolites in the feed of broiler chickens and the effects of the metabolites on performance, bone parameters and meat quality. A total of 952 one-day-old male broiler chicks were distributed in a completely randomised design, with four treatments, seven replicates and 34 birds per experimental unit. The treatments consisted of four different sources of vitamin D included in the diet, $D_3$, $25(OH)D_3$, $1,25(OH)_2D_3$, and $1{\alpha}(OH)D_3$, providing 2000 and 1600 IU of vitamin D in the starter (1 to 21 d) and growth phases (22 to 42 d), respectively. Mean weight, feed:gain and weight gain throughout the rearing period were less in animals fed $1{\alpha}(OH)D_3$ when compared with the other treatments (p<0.05). No significant differences were noted among the treatments (p>0.05) for various bone parameters. Meat colour differed among the treatments (p>0.05). All of the metabolites used in the diets, with the exception of $1{\alpha}(OH)D_3$, can be used for broiler chickens without problems for performance and bone quality, however, some aspects of meat quality were affected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.751-760
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• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.9-16
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• 2007

The present study was aimed to screen different antibiotics in vivo for their effects against the bacterium Bacillus coagulans in silkworm Bombyx mori in three experimental conditions viz., a) healthy larvae treated with the antibiotics b) larvae which were first inoculated with Bacillus coagulans immediately after the $2^{nd}$ moult and treated with the antibiotics from 24 hour after inoculation up to the end of the $5^{th}$ instar(pre-inoculated larvae) and c) larvae which were treated with the antibiotics right from hatching up to the end of the $5^{th}$ instar and inoculated with Bacillus coagulans immediately after the $2^{nd}$ moult(post-inoculated larvae). All the antibiotics used in this study stimulated better performance in improving the rearing performance and economic characters of the cocoons in healthy, pre-inoculated and post-inoculated larvae, besides reducing the mortality of infected larvae. Cephelexin and Tetracycline were more effective than the others in their overall performance under all the three experimental conditions. Chloramphenical caused greater increase in the length of the reelable silk filament, but was not as good in elevating the other parameters compared to the remaining antibiotics. Of the four concentrations of antibiotics tested, 2.0% performed better under all the three experimental conditions.

• Journal of Applied Reliability
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• v.4 no.2
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• pp.73-90
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• 2004

We performed the heat aging test to predict the useful lifetime of Elastomeric Bearing Chloroprene Rubber (CR) used for supporting bridge. During the test, we measured elongation that are influenced by temperature and aging time. The failure of a test piece is defined as the point at which the elongation reaches to 75% of the initial value. This failure criterion is based on KS F 4420: 1998 (Elastomeric Bearing for bridge). Through the accelerated heat aging test, we found that the Arrhenius relationship and the Weibull lifetime distribution are appropriate as the life-temperature relationship and lifetime distribution of the CR, respectively. Using the Arrhenius -Weibull model, the parameters of the model are estimated and the lifetime of the CR at use condition is predicted.

• Human Ecology Research
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• v.58 no.2
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• pp.149-161
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• 2020

This study showed that the association between grandmother-mother relationship and grandmother-grandchildren ties is mediated by the coparenting. Participants consisted of 329 grandmothers who were rearing preschool aged grandchildren in the Seoul and Gyeonggido area. SPSS 23.0 performed descriptive statistical analysis and correlation analysis. The structural equation model was estimated with AMOS 23.0. Parameters were estimated using the maximum likelihood method. Model fit index used the chi-square statistic, the goodness of fit index (GFI), the Turker-Lewis index (TLI), the comparative fit index (CFI), the root mean square error of approximation (RMSEA). The mediation effect analysis followed a two-step verification process; direct and indirect effect. In addition, statistical significance of the indirect effect was examined using a bootstrapping procedure. The results are as follows. First, a positive correlation was found between the grandmother-mother relationship, grandmother-grandchildren ties, and coparenting. Second, the association between grandmother-mother relationship and grandmother-grandchildren ties is mediated by coparenting. The results of this study suggest that the quality of the grandmother's relationship with mothers and cooperative coparenting is important to building relationships with grandchildren. In addition, coparenting can be an important mechanism for grandmother-mother relationships and grandmother-grandchild ties. Based on the results of this study, we discussed ways to improve the grandmothers' relationship quality with the mother and strengthen parenting ability.