• 대한수의학회지
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• 제26권2호
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• pp.329-336
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• 1986

This survey was conducted to investigate the prevalence of the internal parasites of Holstein cattle rearing in western Gyeongnam including Chinyang, Sachun, Namhae, Hadong, Sanchung, Hamyang, Geochang and Hapchun Area(Gun). A total of eight hundred and twenty five heads of Holstein cattle was randomly selected for the faecal examinations and the internal parasitisms were examined by floatation method using saturated salt solution and sedimentation method using 0.5% trio-soap solution. The relults obtained are summarized as follows: 1. The overall rate of internal parasite infections was 67.2% with infection of 554 cases and the non-infected rate was 32.8% with 271 cases from the total number of 825 samples. 2. A total fourteen species of parasites was identified from 825 faecal samples of Holstein cattle and the infection rate of each species of parasites was 3.0% in Haemonchus contortus, 2.7% in Cooperia spp., 1.8% in Bunostomum phlebotomum, 1.6% in Oesophagostomum radiatum, 1.2% in Ostertagia ostertagi, 1.0% in Trichuris bovis, 0.8% in Strongyloides papillsus, 0.4% in Nematodirus spp., 0.1% in Trichostrongylus spp., 57.3% in Paramohistomum spp., 31.2% in Fasciola hepatica, 0.6% in Eurytrema pancreaticum, 0.7% in Moniezia expansa and 5.1% in Eimeria spp. 3. The combined infection of internal parasites was 38.1% in single species, 27.0% in double and 2.1% in triple infections. 4. The EPG levels of each species of parasites were very low in all infected cases except trematodes showing no clinical symptoms.

• Animal Bioscience
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• 제34권2호
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• pp.185-191
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• 2021

Objective: The objective of this study was to estimate the genetic parameters for worm resistance (WR) and associated characteristics, using the linear-threshold animal model via Bayesian inference in single- and multiple-trait analyses. Methods: Data were collected from a herd of Santa Inês breed sheep. All information was collected with animals submitted to natural contamination conditions. All data (number of eggs per gram of feces [FEC], Famacha score [FS], body condition score [BCS], and hematocrit [HCT]) were collected on the same day. The animals were weighed individually on the day after collection (after 12-h fasting). The WR trait was defined by the multivariate cluster analysis, using the FEC, HCT, BCS, and FS of material collected from naturally infected sheep of the Santa Inês breed. The variance components and genetic parameters for the WR, FEC, HCT, BCS, and FS traits were estimated using the Bayesian inference under the linear and threshold animal model. Results: A low magnitude was obtained for repeatability of worm-related traits. The mean values estimated for heritability were of low-to-high (0.05 to 0.88) magnitude. The FEC, HCT, BCS, FS, and body weight traits showed higher heritability (although low magnitude) in the multiple-trait model due to increased information about traits. All WR characters showed a significant genetic correlation, and heritability estimates ranged from low (0.44; single-trait model) to high (0.88; multiple-trait model). Conclusion: Therefore, we suggest that FS be included as a criterion of ovine genetic selection for endoparasite resistance using the trait defined by multivariate cluster analysis, as it will provide greater genetic gains when compared to any single trait. In addition, its measurement is easy and inexpensive, exhibiting greater heritability and repeatability and a high genetic correlation with the trait of resistance to worms.

• Parasites, Hosts and Diseases
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• 제60권5호
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• pp.345-352
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• 2022

Chitinase AO-801 is a hydrolase secreted by Arthrobotrys oligospora during nematode feeding, while its role remained elusive. This study analyzed the molecular characteristics of recombinant chitinase of Arthrobotrys oligospora (reAO-801). AO-801 belongs to the typical glycoside hydrolase 18 family with conserved chitinase sequence and tertiary structure of (α/β)₈ triose-phosphate isomerase (TIM) barrel. The molecular weight of reAO-801 was 42 kDa. reAO-801 effectively degraded colloidal and powdered chitin, egg lysate, and stage I larval lysate of Caenorhabditis elegans. The activity of reAO-801 reached its peak at 40℃ and pH values between 4-7. Enzyme activity was inhibited by Zn2⁺, Ca2⁺, and Fe3⁺, whereas Mg2⁺ and K⁺ potentiated its activity. In addition, urea, sodium dodecyl sulfate, and 2-mercaptoethanol significantly inhibited enzyme activity. reAO-801 showed complete nematicidal activity against C. elegans stage I larvae. reAO-801 broke down the C. elegans egg shells, causing them to die or die prematurely by hatching the eggs. It also invoked degradation of Haemonchus contortus eggs, resulting in apparent changes in the morphological structure. This study demonstrated the cytotoxic effect of reAO-801, which laid the foundation for further dissecting the mechanism of nematode infestation by A. oligospora.