Embryo Transfer And Genetic Differentiation Of Black-Boned Goat

Black-boned goats were analyzed with superovulation, estrus synchronization and species genetic differentiation, hoping to provide basic materials for amplifying the goat population, animal conservation and evaluation.In the first experiment, embryo transfer was conducted in black-boned goat in Youmeite ecological farm (Tongshan County, Hubei Province).The results showed as follows:1. The superovlation dosage of FSH was9.6mg, the average number of collected embryos was8.11±3.18, the average number of available embryos was6.22±1.43, and available embryo ratio reached71.23±20.32%. The superovulation results of FSH from New Zealand were same as FSH from Canada, suggesting that FSH from different area had no significant effect on superovulation and dometic FSH can be used because of economic costs.2. During the estrus synchronization process, CIDR+PG+PMSG could achieve good results. The estrus rate of the Australian PMSG was88.6%while that of Ningbo PMSG was75.9%, and the difference was significant (P<0.05).3. After withdrawing CIDR in estrus synchronization experiments, most of the receptors came into heat24h～48h later and the estrus rate was54.5%.4. Comparing the estrus among three goat breeds, estrus rate was85%,80%and86.1%for Black goat, Boer goat and dairy goat, respectively; however, the difference was not significant (P>0.05).5. The pregnancy rate was significantly different when transplanting one, two, three fresh embryos, and the pregnancy rate were63.6%,60.0%and57.1%, respectively. In order to use the embryos as many as possible, a grade A embryo was enough bo be transplanted while several embryos should be transplanted when the embryos were in lower grade.6. The pregnacy rate was62.50%,57.12%, and66.67%when corpus luteum diameter was big (>0.5cm), medium (0.3～0.5cm) and small (<0.3cm), respectively. However, the pregnacy rate was not significant, suggesting that the size of the corpus luteum did not associate with pregnancy rate.In expereiment two, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was used to detect single nucleotide polymorphisms (SNPs) of PGR, GnRHR, FSHβ, INHβA and LHβ gene were detected in twelve Chinese indigenous goat populations and two introduced goat populations (Lezhi Black goat, Jianchang Black goat, Black bone goat, Liaoning Cashmere goat, Chengdu Grey goat, Chengde Hornless goat, Nanjiang Yellow goat, Matou goat, Jianyang Big Ear goat, Beichuan White goat, Xiangdong Black goat, Jintang Black goat, Boer goat and Nubian goat). The results showed as follows:1. Six SNPs were detected in the five candidated gene. The SNPs were:-31G/A of PGR, A lost at714bp and G inserted at731bp at exon1of GnRHR,-856G/T of FSHβ,80T/C at exon2of INHβA,153C/A and64T/C at exon2of LH(3. The SNPs were named as PGR, GnRHR, FSHβ, INHβA, LHβ-1and LHβ-5.2. The genotype frequencies of the6loci among the14goat breeds were significantly different (P<0.05). The six loci were neutral in the14goat breeds. The observed heterozygosity (Ho) and expected heterozygosity (He)were0.2172～0.6830and0.2100～0.4571among the14goat breeds.The effective number of alleles (Ne) was1.4241～1.8329, the PIC was0.1990～0.3348and the Shannon’s diversity index was0.4092～0.6734.3. F-statistics was used to analyze the variation across populations. Fit, Fst and Fjis were-0.576,0.029, and-0.623, respectively, implying low genetic differentiation among fourteen populations (2.9%).4. The observed heterozygosity (0.2818) of black-boned goat was lower than the expected heterrozygosity (0.3110), indicating heterozygosity deficiency and more homozygous individuals in black-boned goat. The possible reason for the heterozygosity deficiency may be selection, mutation and genetic drift.5. The NJ topology tree derived from the Nei standard genetic distance illustrated genetic relationships among the goat populations. According to the phylogenetic analysis, two imported goats gather for a branch, Matou goat alone clustered into one branch, the other11goat breeds were clustered into three branches. Matou goat had the biggest genetic distance with Lezhi Black goat (0.2829), and the gene flow had been smallest (0.778). The largest gene flow (20.0752) existed between the black-boned goat and Jianyang big ears goat. They had the samllest genetic distance, indicating a close genetic relationship.