| 摘要: | 豬群的繁殖性能是反應豬場生產水準及經濟效率的重要指標，近年來隨著飼養規模的擴大，母豬的生產力偏低的情形也受生產者所重視。根據報告，台灣豬群生產力偏低，提昇繁殖性能的表現是目前國內養豬產業的目標之一。由於繁殖性狀是低遺傳率性狀，無法直接選拔個體進行改進，且受許多遺傳與環境的因素影響，因此需要估算遺傳介量來做為選拔豬群的依據。同時許多候選基因已經被使用在改善母豬的繁殖性能。本研究目的在透過已有的純種豬群結構，配合分子檢測，得知候選基因對於繁殖性狀的表現型關聯性；再利用育種分析軟體來估計豬群繁殖性狀間的變方與共變方成分，並計算出性狀間的遺傳相關及遺傳介量，預期結果可以作為改善豬群繁殖性能的依據。本研究收集2000年至2010年間的豬群系譜、配種及分娩資料共7,618胎，包括藍瑞斯(Landrace, L)、約克夏(Yorkshire, Y)及杜洛克(Duroc, D)三個品種。繁殖性狀有：出生總仔數(litter size at birth, LSB) 、出生活仔數(litter size at born alive, LSA)、21天窩仔數(litter size at 21-day, LS21)、離乳窩仔數(litter size at weaning, LSW)、平均出生個體重(average birth weight, ABW)、平均21天個體重(average 21-day weight, A21W)及平均離乳個體重(average weaning weight, AWW)。利用PCR-RFLP技術檢測豬群ESR及CRC的基因分型，應用混合模式(Mixed Model)與動物模式(Animal Model)進行分析檢測基因型與繁殖性能的關聯性。使用育種分析軟體(VCE 4.2.5)進行遺傳分析，估計各品種母豬群繁殖性狀間的變方及共變方成分，並估算繁殖性狀的遺傳變異率與遺傳及表現型相關。共有259頭藍瑞斯母豬、139頭約克夏母豬與944頭杜洛克母豬具有基因分型資料。CRC (CC, CT, TT) 與 ESR (AA, AB, BB)的基因型頻率分別為L (1.00, 0, 0; 0.86, 0.15, 0), Y (1.00, 0, 0; 0.36, 0.46, 0.18)及D(0.81, 0.18, 0.01; 1.00, 0, 0)。CRC基因對於杜洛克母豬所生產的平均仔豬個體重有顯著影響，CC型母豬表現優於CT型及TT型(P<0.05)。不同ESR基因型對於藍瑞斯母豬與約克夏母豬在不同性狀有不同的表現。而季節的影響對於三個品種的母豬繁殖性能皆有差異，以杜洛克母豬影響最多。胎次對於窩仔數性狀會隨著胎次增加而逐漸增加，除了胎次對於約克夏母豬的出生性狀(LSB、LSA及ABW)沒有顯著差異外，其餘的性狀皆有差異。三個品種繁殖性狀的估計遺傳率範圍分別為LSB(0.18-0.34)、LSA(0.16-0.23)、ABW(0.07-0.19)、LS21(0.13-0.18)、A21W(0.11-0.30)、LSW(0.13-0.19)及AWW(0.01-0.27)。大部分的窩仔數性狀間的表型與遺傳相關皆為正值，窩仔數性狀對於平均窩體重性狀的表型相關為負值。本研究結果指出對於繁殖性能而言，季節與胎次的影響較ESR與CRC基因來得明顯，但在不同品種下則是具有不同特異性。遺傳分析結果顯示不同品種母豬繁殖性狀的遺傳變異率的差異，顯示發展及應用多品種豬群繁殖性狀遺傳評估方法之必要性。
Reproductive performance is an important key to reflect the production level of a swine herd. Sow herd reproductivity in Taiwan is relatively low in comparison of the result from annual report. Therefore, it is important to improve sow herd reproductivity in Taiwan. Reproductive trait is low heritability trait, and this will be affected by genetic and environment. Estimating genetics parameter was the better way for improving reproductive traits. Many molecular technologies are applied to detect the candidate genes which relate to reproductive traits. Using the reproductive data from purebred Landrace, Yorkshire, and Duroc sows, the objectives of this study are (1) to study the association of candidate gene with reproductive traits, (2) to estimate heritabilities for various reproductive traits, and (3) to estimate phenotypic and genotypic correlations. Records of pedigree, mating, farrowing, and weaning information on 7,618 litters born between 2000 and 2010 from a breeding herd will be used in this study. Reproductive traits including litter size at birth (LSB), litter size born alive (LSA), litter size at 21 d (LS21), litter size at weaning (LSW), average birth weight (ABW), average 21d weight (A21W), and average weaning weight (AWW). ESR and CRC gene polymorphisms by PCR-RFLP analysis, and use Mixed Model and Animal Model to analysis the association of candidate gene with reproductive traits. Variance components for reproductive traits were estimated from Landrace, Yorkshire, and Duroc litters using VCE(4.2.5), and to estimate heritabilities for various reproductive traits, and to estimate phenotypic and genotypic correlations. Genetic markers data on 259 Landrace, 139 Yorkshire, and 944 Duroc were collected. Genotypic frequencies of CRC (CC, CT, TT) and ESR (AA, AB, BB) were L (1.00, 0, 0; 0.86, 0.15, 0), Y (1.00, 0, 0; 0.36, 0.46, 0.18), D(0.81, 0.18, 0.01; 1.00, 0, 0), respectively. CRC gene had significant difference between average piglet weight form Duroc sows. CC genotype had better performance than CT and TT type(P<0.05). Different ESR genotype had different effect on each reproduction traits in Landrace and Yorkshire. Significant season effect (P<0.05) showed on reproductive traits in three breeds, and most effect in Duroc. Parity effect showed on litter size traits were increase with parity no, except of born trait (LSB, LSA, and ABW) in Yorkshire sows. Estimates of heritability ranged from 0.18-0.34 for LSB; 0.16-0.23 for LSA; 0.07-0.19 for ABW; 0.13-0.18for LS21; 0.11-0.30 for A21W; 0.13-0.19 for LSW; and 0.01-0.27 for AWW, in Landrace, Yorkshire and Duroc breeds, respectively. Genetic and Phenotypic correlations between the most litter size traits were all positive in all three breeds. And phenotypic correlations between the litter size traits and average weight traits were negative. This study presents the season and parity effect of reproductive traits were more significant than ESR and CRC effect. But it has breed-specific to each breed. Results of genetic analysis showed the difference on heritabilities of reproductive traits between each breed, that showed important to develop and applied the methods of evaluate genetics for reproductive traits on each breed. |
