■在撒哈拉以南非洲,80%的家禽生产在小农户农场,鸡通常在户外自由放养条件下饲养。在这些条件下,对鸡的表型特征和遗传学的了解有限。
■目前是一项大规模研究,旨在从表型上表征热带适应的商品鸡在典型小农农场条件下的表现,并检查与生长相关的鸡表型的遗传特征,肉类生产,豁免权,和生存。
■在亚的斯亚贝巴国际家畜研究所的家禽设施中,共有2,573只T451A两用萨索鸡在模拟的自由放养条件下饲养在户外,埃塞俄比亚,包括在研究中。将鸡在五个相同大小的批次中饲养,并从56日龄开始单独监测和表型分析,持续8周。收集的单个鸡数据包括每周体重,增长率,屠宰时的身体和胸肉重量,在研究开始和结束时记录的新城疫病毒(NDV)滴度和肠道免疫球蛋白A(IgA)水平,以及同期的存活率。使用低覆盖率和插补方法对所有鸡进行通过测序的基因分型。在基因组关联分析中组合鸡表型和基因型。
■我们发现鸡的表型多样,在所有性状中观察到广泛的变异水平。鸡的批号和性别显着影响研究的表型。遵循质量保证,基因型由290万个用于基因组分析的单核苷酸多态性标记组成。结果揭示了所有表型性状的遗传控制的主要多基因模式。然而,确定了15种与生长显着相关的不同标记,car体性状,NDV滴度,IgA水平,鸡的生存这些标记位于包含相关注释基因的区域中。
结果表明,在小农农场条件下饲养的鸡的性能适合遗传改良,并可能为撒哈拉以南非洲提高鸡生产力的选择性育种计划提供信息。
UNASSIGNED: In sub-Saharan Africa, 80% of poultry production is on
smallholder village farms, where chickens are typically reared outdoors in free-ranging conditions. There is limited knowledge on chickens\' phenotypic characteristics and genetics under these conditions.
UNASSIGNED: The present is a large-scale study set out to phenotypically characterise the performance of tropically adapted commercial chickens in typical
smallholder farm conditions, and to examine the genetic profile of chicken phenotypes associated with growth, meat production, immunity, and survival.
UNASSIGNED: A total of 2,573 T451A dual-purpose Sasso chickens kept outdoors in emulated free-ranging conditions at the poultry facility of the International Livestock Research Institute in Addis Ababa, Ethiopia, were included in the study. The chickens were raised in five equally sized batches and were individually monitored and phenotyped from the age of 56 days for 8 weeks. Individual chicken data collected included weekly body weight, growth rate, body and breast meat weight at slaughter, Newcastle Disease Virus (NDV) titres and intestinal Immunoglobulin A (IgA) levels recorded at the beginning and the end of the period of study, and survival rate during the same period. Genotyping by sequencing was performed on all chickens using a low-coverage and imputation approach. Chicken phenotypes and genotypes were combined in genomic association analyses.
UNASSIGNED: We discovered that the chickens were phenotypically diverse, with extensive variance levels observed in all traits. Batch number and sex of the chicken significantly affected the studied phenotypes. Following quality assurance, genotypes consisted of 2.9 million Single Nucleotide Polymorphism markers that were used in the genomic analyses. Results revealed a largely polygenic mode of genetic control of all phenotypic traits. Nevertheless, 15 distinct markers were identified that were significantly associated with growth, carcass traits, NDV titres, IgA levels, and chicken survival. These markers were located in regions harbouring relevant annotated genes.
UNASSIGNED: Results suggest that performance of chickens raised under
smallholder farm conditions is amenable to genetic improvement and may inform selective breeding programmes for enhanced chicken productivity in sub-Saharan Africa.