【摘要】：在畜禽生產(chǎn)中,飼料成本占到養(yǎng)殖總成本的60%以上。持續(xù)上漲的飼料價格和畜牧生產(chǎn)中的環(huán)境污染問題促使遺傳育種學(xué)家將采食量和飼料利用率性狀作為重要的選育目標(biāo)進行改良。隨著蛋雞產(chǎn)蛋周期的不斷延長,改善蛋雞產(chǎn)蛋后期個體飼料利用率成為一個需要關(guān)注的議題。本文利用一個雞F2分離群體和一個純系核心育種群,通過對采食量和飼料利用率性狀進行遺傳參數(shù)估計和全基因組關(guān)聯(lián)分析(GWAS),研究這些性狀在不同產(chǎn)蛋階段遺傳基礎(chǔ),為性狀改良提供參考。本研究構(gòu)建了白來航與東鄉(xiāng)綠殼蛋雞的F2分離群體,并測定群體在37～40 (T1)和57～60周齡(T2)的剩余采食量(RFI)、飼料轉(zhuǎn)化率(FCR)、采食量(FI)、維持體重(MBW)、體增重(BWG)和產(chǎn)蛋量(EM)等性狀表型值。應(yīng)用動物模型結(jié)合AI-REML方法對這些性狀進行遺傳力和遺傳相關(guān)系數(shù)估計。結(jié)果顯示T1階段的RFI、FCR和FI的遺傳力分別為0.21、0.19和0.20;T2階段的估計值分別為0.29、0.13和0.26。兩個階段中,RFI與FCR (0.51、0.43)、FI (0.72、0.84)高度遺傳正相關(guān);而F1與FCR之間的遺傳相關(guān)系數(shù)則很小(-0.09、0.11)。RFI與其組分性狀MBW、EM和BWG之間呈負相關(guān)(-0.47～-0.01)。此外,T1階段FI、RFI和FCR與T2階段對應(yīng)性狀間均呈現(xiàn)高遺傳相關(guān),介于0.76～0.94,表明兩階段間性狀的遺傳背景相似,適合于早期選擇。研究結(jié)果表明通過選擇低RFI (高效率)的個體,會降低采食量而對產(chǎn)蛋量影響很小,選擇FCR則會提高產(chǎn)蛋量,對采食量影響很小。這些研究結(jié)果為產(chǎn)蛋階段飼料轉(zhuǎn)化效率性狀的改良提供了理論依據(jù)。利用雞600K高密度SNP芯片對F2群體中1,534母雞個體進行基因分型,應(yīng)用全基因組高效混合模型關(guān)聯(lián)算法(GEMMA)對FI、RFI和FCR進行了單性狀、二性狀和條件GWAS分析。試驗中的全基因組顯著性閾值由SimpleM方法推斷得到。GWAS分析檢測到8個基因組區(qū)域與采食量性狀顯著相關(guān),其中1個關(guān)聯(lián)區(qū)域與早前在蛋雞群體中報道的QTL區(qū)域吻合。單性狀和二性狀GWAS鑒定到8個共有SNP同時影響兩個階段的采食量。這8個SNP位于1號染色體169.23～171.55 Mb區(qū)域內(nèi),分別解釋T1和T2階段采食量表型方差的3.72%和2.57%。CAB39L和GIP是分別與T1和T2采食量顯著關(guān)聯(lián)的重要候選基因。GWAS鑒定到1個與T2階段RFI顯著關(guān)聯(lián)的SNP位點rs315135692,位于27號染色體上的連鎖塊中,且不同基因型純合子的表型差異達到3.35克/天,其中主要等位基因可提高飼料利用率,次要等位基因可降低飼料利用率。此外,二性狀GWAS在1號染色體上鑒定到的與FCR強相關(guān)的信號值得進一步研究。本研究結(jié)果證明了采食量性狀的多基因遺傳效應(yīng)。GWAS檢測到了多個控制采食量的新遺傳變異并印證了一個早前報道的QTL。與飼料利用率相關(guān)的遺傳變異可用于基因組選擇中來選擇更高效的蛋雞個體。本研究還測定了808只洛島紅純系母雞個體在80～81周齡的FI、RFI和FCR的表型,并對這些性狀進行遺傳參數(shù)估計和全基因組關(guān)聯(lián)分析,最后通過分子試驗驗證與性狀相關(guān)的候選基因�；谙底V和SNP數(shù)據(jù)的遺傳參數(shù)估計結(jié)果顯示,采食量和飼料利用率性狀遺傳力介于0.15-0.28,屬中等遺傳力,而這些性狀之間則是高度遺傳相關(guān),相關(guān)系數(shù)介于0.49～0.9。全基因組關(guān)聯(lián)分析在1號染色體上鑒定到3個SNP位點與飼料轉(zhuǎn)化率顯著相關(guān),這3個SNP彼此間高度連鎖,位于gga-miR-15a上游13.55～45.16Kb區(qū)間內(nèi)。實時熒光定量試驗(qRT-PCR)的結(jié)果顯示gga-miR-15a在高FCR組個體肝臟中的表達量要顯著高于中等FCR和低FCR組個體。進一步的生物信息學(xué)分析結(jié)果表明gga-miR-15a可以結(jié)合到多個靶向基因上,其中就包括FOXO1基因,這個基因參與到胰島素信號通路中,影響營養(yǎng)代謝的過程,是可能性最大的候選基因。此外,GWAS在3和9號染色體上鑒定到若干個與FI和RFI潛在顯著關(guān)聯(lián)的SNP位點。本研究是首次對加長產(chǎn)蛋期采食量和飼料效率性狀進行遺傳學(xué)分析的報道。研究結(jié)果可作為基因組育種方案制定的重要依據(jù),并有利于我們更好的理解飼料利用率性狀的遺傳基礎(chǔ)。
[Abstract]:In the production of livestock and poultry, the feed cost accounts for more than 60% of the total breeding cost. The continuous rising feed price and the environmental pollution in the livestock production make the genetic breeders improve the food intake and feed utilization traits as an important breeding target. With the continuous extension of the laying week period of laying hens, the later period of laying eggs is improved. The utilization rate of body feed has become a topic of concern. In this paper, a chicken F2 separation group and a pure line core breeding group are used to estimate genetic parameters and complete genome association analysis (GWAS) for feed intake and feed utilization traits to study the genetic basis of these traits at different laying stages and provide reference for the improvement of the traits. This study constructed the F2 population of white Lai hang and Dongxiang green shell laying hens, and measured the remaining feed intake (RFI), feed conversion rate (FCR), feed intake (FI), MBW, BWG, and egg production (EM) in 37~40 (T1) and 57~60 week age (T2). The heritability of heredity and genetic correlation was estimated. The results showed that the heritability of RFI, FCR and FI at T1 stage was 0.21,0.19 and 0.20, and the estimated values of T2 stage were 0.29,0.13 and 0.26., respectively, RFI and FCR (0.51,0.43) and FI. The components of MBW, EM and BWG were negatively correlated (-0.47 to -0.01). In addition, FI, RFI and FCR and T2 stages were high genetic correlation in T1 stage, between 0.76 and 0.94, indicating that the genetic background of the two stages was similar and suitable for early selection. The effect of FCR on egg production is very small. The selection of FCR will increase the amount of egg production, which has a small influence on the feed intake. These results provide a theoretical basis for the improvement of feed conversion efficiency in the laying stage. Using the 600K high density SNP chip of chicken to genotyping the 1534 hens in the F2 population and the association of the whole genome high efficiency mixture model. The algorithm (GEMMA) carried out a single trait, two sex and conditional GWAS analysis of FI, RFI and FCR. The total genomic significance threshold in the experiment was deduced from SimpleM method to determine that the 8 genome regions were significantly correlated with the feed intake traits, and 1 of them were consistent with the QTL region reported earlier in the egg chicken population. Two sexual GWAS identified 8 common SNP and affected the feed intake of two stages. The 8 SNP was located in the 169.23 to 171.55 Mb region of chromosome 1, explaining 3.72% of the phenotypic variance of feed intake at T1 and T2 stages, and 2.57%.CAB39L and GIP are important candidates for the significant candidate genes associated with T1 and T2 feed intake, respectively, to 1 and T2 stages The significant association SNP site rs315135692 is located in the linkage block on chromosome 27, and the phenotypic difference of different genozygotes reaches 3.35 g / day, of which the main allele can increase the feed utilization and secondary alleles can reduce the feed utilization. In addition, the FCR strongly related letter identified by the second sex GWAS on chromosome 1 It is worth further study. The results of this study demonstrate that the polygenic effect of feed intake traits.GWAS detected a number of new genetic variations that control feed intake and confirmed that a previously reported genetic variation associated with the feed utilization rate of QTL. could be used to select more efficient egg chicken individuals in the selection of genome. The phenotypes of FI, RFI and FCR at 80~81 weeks of age in 808 luoisu red pure lineage hens were estimated and the genetic parameter estimation and whole genome association analysis were performed on these traits. Finally, the candidate genes related to the traits were verified by molecular tests. Genetic parameter estimation based on pedigree and SNP data showed that feed intake and feed utilization traits were shown. Heritability is between 0.15-0.28 and moderate heritability, and the correlation between these traits is highly genetic correlation. The correlation coefficient is between 0.49 and 0.9. genome association analysis on chromosome 1 and 3 SNP loci are closely related to the feed conversion rate. The 3 SNP are highly linked to each other and are located in the 13.55 ~ 45.16Kb range of the upstream of gga-miR-15a. The results of the time fluorescence quantitative test (qRT-PCR) showed that the expression of gga-miR-15a in the liver of the high FCR group was significantly higher than that of the medium and low FCR individuals. Further bioinformatics analysis showed that gga-miR-15a could be combined with multiple target genes, including the FOXO1 gene, which was involved in insulin signaling. In the road, the process of influencing nutrition metabolism is the most likely candidate gene. In addition, GWAS has identified several SNP loci potentially associated with FI and RFI on the 3 and 9 chromosomes. This study is the first report on the genetic analysis of feed intake and feed efficiency traits during long laying period. The results can be used as a genome breeding party. The important basis for formulating the case will help us better understand the genetic basis of feed utilization traits.
【學(xué)位授予單位】：中國農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S831

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