• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.1007-1014
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• 2007

Acceptance of antibiotic growth promoters (AGP) in agricultural animal production is rapidly disappearing. Both government regulations and consumer preference are driving this change. Producers in any country that seek export markets will be forced to give up AGP if they are to sell to the EU and many other markets. This report will first review the history of AGP use in the animal industry and the concerns about development of antimicrobial resistance. A description of the development and structure of the gut and how it is affected by AGP administration will conclude with results of studies to replace AGP with antimicrobial organic acids.

• Korean Journal of Veterinary Research
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• v.60 no.3
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• pp.163-171
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• 2020

This study examined the prevalence of adherence factors, toxin genes, antimicrobial resistance phenotypes, and resistance genes in Escherichia coli (E. coli) isolated from piglets with diarrhea before and after the ban on antibiotic growth promoters (AGPs) in Korea from 2007 to 2018. In this period, pathogenic 474 E. coli isolates were obtained from diarrheic piglets. The virulence factors and antimicrobial resistance genes were assayed using a polymerase chain reaction, and the susceptibility to antibiotics was tested according to the Clinical and Laboratory Standards Institute guidelines. After the ban on AGPs, the frequency of F4 (12.5% to 32.7%) increased significantly, and LT (31.9% to 20.3%) and EAST-I (46.5% to 35.2%) decreased significantly. In addition, the resistance to streptomycin (45.8% to 67.9%), cephalothin (34.0% to 59.4%), and cefazlin (10.4% to 28.8%) increased significantly. Colistin resistance plasmid-mediated genes, mcr-1 and mcr-3, were detected after the ban on AGPs. The results of this study can provide useful data for analyzing the impact of the ban on AGPs on the virulence profiles and antimicrobial resistance of E. coli isolated from piglets with diarrhea in Korea.

• Toxicological Research
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• v.26 no.4
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• pp.301-313
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• 2010

Growth promoters including hormonal substances and antibiotics are used legally and illegally in food producing animals for the growth promotion of livestock animals. Hormonal substances still under debate in terms of their human health impacts are estradiol-$17\beta$, progesterone, testosterone, zeranol, trenbolone, and melengestrol acetate (MGA). Many of the risk assessment results of natural steroid hormones have presented negligible impacts when they are used under good veterinary practices. For synthetic hormonelike substances, ADIs and MRLs have been established for food safety along with the approval of animal treatment. Small amounts of antibiotics added to feedstuff present growth promotion effects via the prevention of infectious diseases at doses lower than therapeutic dose. The induction of antimicrobial resistant bacteria and the disruption of normal human intestinal flora are major concerns in terms of human health impact. Regulatory guidance such as ADIs and MRLs fully reflect the impact on human gastrointestinal microflora. However, before deciding on any risk management options, risk assessments of antimicrobial resistance require large-scale evidence regarding the relationship between antimicrobial use in food-producing animals and the occurrence of antimicrobial resistance in human pathogens. In this article, the risk profiles of hormonal and antibacterial growth promoters are provided based on recent toxicity and human exposure information, and recommendations for risk management to prevent human health impacts by the use of growth promoters are also presented.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1348-1353
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• 2010

A grower broiler experiment (from 14 to 35 days of age) was conducted to study the effect of using two commercial mixtures of organic acids (Galliacid$^{(R)}$ and Biacid$^{(R)}$) to substitute antibiotic growth promoter (Eneramycin$^{(R)}$) on performance, carcass characteristics and intestinal microflora. 400 (Ross 308) broiler chicks were used. A basal corn-soybean meal diet were formulated and served as a control treatment. The control diet was supplemented with either 0.06% Galliacid, 0.1% Biacid or 0.02% Eneramycin. Birds fed the Galliacid-supplemented diet had 16% (p<0.001) more gain than the control, while those fed the Biacid- or Enramycinsupplemented diets recorded 3 and 5.5% more gain, respectively. Organic acids mixtures and Enramycin supplementation significantly (p<0.001) improved feed conversion ratio. These results indicated that birds fed either organic acid mixtures or Enramycinsupplemented diets utilized feed more efficiently than those fed the control diet. Galliacid significantly (p<0.01) increased dressing percentage and bursa weight (% body weight). No significant differences were detected on liver, spleen and thymus (% body weight) among treatments. Galliacid or Biacid significantly (p<0.001) decreased intestinal Escherichia coli and Salmonella compared to the control and Enramycin-supplemented diets. Dietary Enramycin significantly (p<0.001) decreased Escherichia coli, but had no effect on Salmonella counts. In conclusion, organic acid mixtures are more efficient than antibiotic growth promoter (Enramycin) in improving broiler performance and decreasing intestinal Escherichia coli and Salmonella spp., and could be successfully used to substitute antibiotic growth promoters in broiler diets. However, not all of the organic acid mixtures gave the same effect either on performance or intestinal bacterial counts.

• Animal Bioscience
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• v.36 no.7
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• pp.1059-1066
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• 2023

Objective: Present study was designed to evaluate the efficacy of Acacia nilotica bark extract as an alternative to antibiotic growth promoters in broilers. Methods: Six hundred, day-old broiler chicks were randomly divided into six groups (NC, without any supplementation; AB, NC+Zinc Bacitracin; PB, NC+Safmannan; ANBE1, NC+A. nilotica bark extract 0.1%; ANBE3, NC+A. nilotica bark extract 0.3%; ANBE5, NC+A. nilotica bark extract 0.5%), with ten replicates per group (10 chicks/replicate) and feeding trial was lasted for 35 days. Results: Results showed that weight gain (1,296.63 g) and feed conversion ratio (FCR, 1.59) of AB was better than NC, during the finisher phase. Overall FCR of AB (1.53), PB (1.54), and ANBE5 (1.54) was significantly (p<0.05) better than NC. From carcass parameters relative weight of wing and heart were highest in ANBE3 (2.5% and 1.51%, respectively). Significantly (p<0.05) highest blood glucose level was observed in NC (264.5 mg/dL) and highest albumin concentration was found in AB (1.46 mg/dL). In addition, antibody titer levels against ND and IBD were higher in ANBE5 than NC, while higher relative weight of bursa was observed in ANBE3 than NC. The villus height to crypt depth ratio in all experimental groups was better than NC. Conclusion: Acacia nilotica bark extract could be a suitable alternative to antibiotic growth promoters to support the growth in broilers.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.9
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• pp.1300-1308
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• 2016

This study was conducted to evaluate the effects of phytogenic additive and antibiotic growth promoter in laying Japanese quails. One hundred and sixty five quails were divided into three groups of 5 replicates and 11 quails (8 females and 3 males) in each replicate. Treatment 1 was fed control diet, treatment 2 was fed control diet supplemented with 0.05% bacitracin methylene disalicylate as antibiotic growth promoter and treatment 3 was fed control diet supplemented with 0.1% phytogenic feed additive (PFA) for two periods of 3 weeks each from 37 to 42 weeks of age. Results showed that egg production, eggshell strength, eggshell weight, villus height and villus height to crypt depth ratio were significantly (p${\leq}$0.05) increased and feed consumption, feed conversion ratio, albumen, Haugh unit, cholesterol, low-density lipoprotein, alanine transaminase, gamma glutamyltransferase, alkaline phosphatase, high-density lipoprotein, triglyceride, number of goblet cell, crypt depth and intestinal bacterial population of Coliforms, Salmonella and E. coli were significantly (p${\leq}$0.05) decreased in PFA fed group. It is concluded that addition of PFA containing phytomolecules and organic acids as main ingredients could significantly improve the production parameters and the general health of laying quails as an alternative to antibiotic growth promoters.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.391-395
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• 2004

• Food Science of Animal Resources
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• v.36 no.5
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• pp.567-576
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• 2016

Poultry industry has always been a dynamic and integral part of national economies in many countries. Economic losses incur especially in large-scale rearing facilities, often attributed to the deterioration of environmental conditions, poultry exposure to stressors and development of diseases. While antibiotics have been commonly used for prophylactic purposes and as growth stimulants, extensive documentation of antimicrobial resistance among pathogenic bacteria due to indiscriminate utilization of antibiotic in the industry has led to public and governmental outcries. Elimination of antibiotics from poultry production has thus encouraged intensive search for alternatives. In this review, we discuss the immense potential of probiotics to fill the gap as alternative growth promoters and evidences of beneficial effects of probiotic application in poultry production.

• Animal Bioscience
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• v.34 no.3_spc
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• pp.345-353
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• 2021

Phytobiotics, also known as phytochemicals or phytogenics, have a wide variety of biological activities and have recently emerged as alternatives to synthetic antibiotic growth promoters. Numerous studies have reported the growth-promoting effects of phytobiotics in chickens, but their precise mechanism of action is yet to be elucidated. Phytobiotics are traditionally known for their antioxidant activity. However, extensive investigations have shown that these compounds also have anti-inflammatory, antimicrobial, and transcription-modulating effects. Phytobiotics are non-nutritive constituents, and their bioavailability is low. Nonetheless, their beneficial effects have been observed in several tissues or organs. The health benefits of the ingestion of phytobiotics are attributed to their antioxidant activity. However, several studies have revealed that not all these benefits could be explained by the antioxidant effects alone. In this review, I focused on the bioavailability of phytobiotics and the possible mechanisms underlying their overall effects on intestinal barrier functions, inflammatory status, gut microbiota, systemic inflammation, and metabolism, rather than the specific effects of each compound. I also discuss the possible mechanisms by which phytobiotics contribute to growth promotion in chickens.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.431-438
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• 2015

Ever since the ban on antibiotic growth promoters (AGPs), the livestock death rate has increased owing to pathogenic bacterial infections. There is a need of developing AGP alternatives; however, the mechanisms by which AGP enhances livestock growth performance are not clearly understood. In this study, we fed 3-week-old swine for 9 weeks with and without AGPs containing chlortetracycline, sulfathiazole, and penicillin to investigate the effects of AGPs on swine gut microbiota. Microbial community analysis was done based on bacterial 16S rRNA genes using MiSeq. The use of AGP showed no growth promoting effect, but inhibited the growth of potential pathogens during the early growth stage. Our results showed the significant increase in species richness after the stabilization of gut microbiota during the post-weaning period (4-week-old). Moreover, the swine gut microbiota was divided into four clusters based on the distribution of operational taxonomic units, which was significantly correlated to the swine weight regardless of AGP treatments. Taxonomic abundance analysis indicated a negative correlation between host weight and the abundance of the family Prevotellaceae species, but showed positive correlation to the abundance of the family Spirochaetaceae, Clostridiaceae_1, and Peptostreptococcaeae species. Although no growth performance enhancement was observed, the use of AGP inhibited the potential pathogens in the early growth stage of swine. In addition, our results indicated the ecological succession of swine gut microbiota according to swine weight. Here, we present a characterization of swine gut microbiota with respect to the effects of AGPs on growth performance.