• Animal Bioscience
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• v.36 no.4
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• pp.591-600
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• 2023

Objective: We aimed to evaluate the efficacy of a modified Double-Ovsynch protocol vs artificial insemination following estrus detection (AIED) for the enhancement of reproductive performance in Hanwoo cattle. Methods: Four hundred twelve Hanwoo cows were allocated to two treatment groups. The first group of cows were administered gonadotropin releasing hormone (GnRH) on Day 36 (±0.6), prostaglandin F_2α (PGF_2α) on Day 46 (8 to 12 days later), and GnRH on Day 49, which was followed by Ovsynch, consisting of an injection of GnRH on Day 56, PGF_2α on Day 63, and GnRH 56 h and timed AI (TAI) 16 h later (modified Double-Ovsynch group, n = 203). The second group of cows underwent AIED (AIED group, n = 209) and were designated as controls. Results: The pregnancy per AI 60 days after the first AI was higher in the modified Double-Ovsynch (68.5%) than in the AIED (56.5%) group, resulting in a higher probability of pregnancy per AI (odds ratio: 1.68, p<0.05). Moreover, cows in the modified Double-Ovsynch group were more likely (hazard ratio: 1.28, p<0.05) to be pregnant by 150 days after calving than cows in the AIED group, and this difference was associated with a lower mean number of AIs per conception (1.27 vs 1.39, p<0.05) and a shorter median interval between calving and pregnancy (72 vs 78 days, p<0.1). Conclusion: The modified Double-Ovsynch protocol, adjusted according to the herd visit schedule, can be readily used to increase the pregnancy per AI following the first AI and to shorten the interval between calving and pregnancy in beef herds.

• Fisheries and Aquatic Sciences
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• v.22 no.12
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• pp.30.1-30.11
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• 2019

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 ㎍ ml^-1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 ㎍ ml^-1) and T. maritimum (0.25 ㎍). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 ㎍ ml^-1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.69-81
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• 1995

This study was conducted to examine the genetic variants of the blood proteins and enzymes in beef cattle breeds, Hereford, Angus and Sharolais reared at the Daekwanryuong Branch of the National Livestock Research Institute. Genetic polymorphisms of transferrin(Tf), post-transferrin2(pTf-2), albumin(Alb), post-albumin (pAlb), ceruloplasmin(Cp), amylase-I(Am-I) and hemoglobin(Hb) in blood were analyzed by the methods of PAGE(polyacrylamide gel electrophoresis) and STAGE(starch gel electrophoresis). The results obtained from this study were summarized as follows: 1. Tf and pTf-2 locus assumed to be controlled by codominant alleles, A. $D_1$, $D_2$ and E allele for Tf, F and S allele for pTf-2. In genotype frequencies, 25% and 90% for Tf $D_1D_2$ and pTf-2 SS in Hereford, 25% and 100% for Tf $AD_1$ and pTf-2 FF in Angus, 50% for Tf $D_1D_1$ and pTf-2 FS in Sharolais were found to have the highest frequency, respectively. In gene frequencies, 0.400 and 0.900 for Tf E and pTf-2 S allele in Hereford, 0.678 and 0.607 for Tf $D_1$ and pTf-2S in Sharolais were appeared to have the highest frequency. 2. Alb and pAlb locus assumed to be controlled by codominant alleles, only A allele for Alb, F and S allele for pAlb. In genotype frequencies, 70% for pAlb SS in Hereford, 90% for pAlb FF in Angus and 57.15% for pAlb SS in Sharolais were found to have the highest frequency. In gene frequencies, 0.825 and 0.750 for pAlb S in Hereford and Charolais, 0.900 for pAlb F in Angus were found to have the highest frequency. 3. Cp and Am-I locus appeared to be controlled by two alleles, F and S allele for Cp, B and C allele for Am-I. In genotype frequencies, 100% and 65% for Cp FF and Am-I BB in Hereford, 45% and 85% for Cp FF, and Am-I CC in Angus, 50% and 64.29% for Cp FF and Am-I BC in Sharolais were found to have the highest frequency. Gene frequencies were 1,000, 0.600 and 0.750 for Cp F in Herehord, Angus and Sharolais, 0.800, 0.875 and 0.680 for Am-I B, C and C allele in Hereford, Angus and sharolais, respectively. 4. Hb locus assumed to be controlled by codominant alleles, only A allele in Hereford and Angus, A and B allele in Sharolais. Genotype frequencies were 57.14% and 42.86% for Hb AA and AB in Sharolais, and gene frequencies were 0.785 and 0.215 for Hb A and B in Sharolais.