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Thu HDT, Binh NTT, Duc LD, Huu DB, Nhung DT, Xuan CN, Viet LN, Thai AN, Quang ML, Pham DK, Hoang TN. 2020. Indigenous Lien Minh chicken of Vietnam: Phenotypic characteristics and single nucleotide polymorphisms of GH, IGFBP and PIT candidate genes related to growth traits. Biodiversitas 21: 5344-5352. Lien Minh chicken, a Vietnamese indigenous breed, has contributed importantly to the economic development of rural citizens in Cat Ba island, Hai Phong province due to its highly desired characteristics. However, Lien Minh chickens showed a slower growth rate when compared to other industrial chicken breeds. Therefore, the study aims at assessing the appearance characteristics and growth performance of 100 individuals Lien Minh chickens, and investigating the single nucleotide polymorphisms (SNPs) of candidate genes including GH, IGFBP and PIT, which might be associated with growth traits. Blood samples were collected from wing of Lien Minh chickens and used for DNA extraction. Genotyping by the PCR-RFLP method was then conducted. The allele frequencies were 0.97 and 0.03 for alleles A and G of GHi3 gene, respectively. For in IGFBP2 gene, allele frequencies were found as 0.47 for the A allele and 0.53 for G allele. The allele frequencies for PIT1 gene were recorded as 100% for allele B. These polymorphic loci (GHi3, PIT1, and IGFBP2) were followed by the Hardy-Weinberg equilibrium in the Lien Minh chicken population. These were the initial results, which could be used to analyze the correlation of molecular markers and growth traits in Lien Minh chickens.

Aquaculture systems are highly complex, dynamic and interconnected systems influenced by environmental, biological, cultural, socio-economic and human behavioural factors. Intensification of aquaculture production is likely to drive indiscriminate use of antibiotics to treat or prevent disease and increase productivity, often to compensate for management and husbandry deficiencies. Surveillance or monitoring of antibiotic usage (ABU) and antibiotic resistance (ABR) is often lacking or absent. Consequently, there are knowledge gaps for the risk of ABR emergence and human exposure to ABR in these systems and the wider environment. The aim of this study was to use a systems-thinking approach to map two aquaculture systems in Vietnam – striped catfish and white-leg shrimp – to identify hotspots for emergence and selection of resistance, and human exposure to antibiotics and antibiotic-resistant bacteria. System mapping was conducted by stakeholders at an interdisciplinary workshop in Hanoi, Vietnam during January 2018, and the maps generated were refined until consensus. Thereafter, literature was reviewed to complement and cross-reference information and to validate the final maps. The maps and component interactions with the environment revealed the grow-out phase, where juveniles are cultured to harvest size, to be a key hotspot for emergence of ABR in both systems due to direct and indirect ABU, exposure to water contaminated with antibiotics and antibiotic-resistant bacteria, and duration of this stage. The pathways for human exposure to antibiotics and ABR were characterised as: occupational (on-farm and at different handling points along the value chain), through consumption (bacterial contamination and residues) and by environmental routes. By using systems thinking and mapping by stakeholders to identify hotspots we demonstrate the applicability of an integrated, interdisciplinary approach to characterising ABU in aquaculture. This work provides a foundation to quantify risks at different points, understand interactions between components, and identify stakeholders who can lead and implement change., Graphical abstract Unlabelled Image, Highlights • The contribution of aquaculture to antibiotic resistance is not well understood. • Systems mapping was used for two aquaculture systems in Vietnam. • Hotspots were identified for the emergence/selection of antibiotic resistance. • Human exposure points to antibiotics and antibiotic-resistant bacteria were mapped. • Findings inform risk quantification and identification of stakeholders to effect change.

Vietnam is an important producer of aquaculture products, and aquatic products are essential to the Vietnamese diet. However, Vietnam also has very little enforced regulation pertaining to antibiotic usage in domestic aquaculture, which raises concerns for antibiotic resistance in pathogenic bacteria. In this study, analysis was conducted on the presence of antibiotic residues in domestically sold fish and shrimp raised in freshwater farms in Vietnam, and an assessment of farmers’ knowledge of proper antibiotics usage was performed. The results indicated that a quarter of tested aquaculture products were antibiotic screening test positive, and there is a general lack of knowledge about the purpose and proper usage of antibiotics by aquaculture producers. Farmers’ decision-making processes about antimicrobial use are influenced by biased sources of information, such as drug manufacturers and sellers, and by financial incentives. Electronic supplementary material The online version of this article (doi:10.1007/s10393-014-1006-z) contains supplementary material, which is available to authorized users.