| Juvenile in Vitro Embyro Transfer(JIVET)is a rapid propagation technology that integrates a series of breeding techniques such as lamb superovulation,oocyte in vitro maturation(IVM),in vitro fertilization(IVF),in vitro culture(IVC)and embryo transfer.This study was conducted to shorten the generation interval of multiple fine wool sheep breeding by using JIVET.The male parent was Booloola(FecB gene type BB),and the female parent was Xinji fine-wool sheep(FecB gene type ++).The influence factors of JIVET had been explored and the performance evaluation of JIVET technology had been conducted,which would assist to further explore and optimize JIVET technology for research and make reasonable recommendations.Exp.1 Effect of JIVET technology on in vitro development and embryo transfer of oocytesThe sheep were selected from the F1 generation lambs of the Booroola Merino sheep and the Xinji fine-wool sheep(14 lambs),the F2 generation lambs produced by the JIVET technology in the F1 generation(15 lambs),and the F3 generation lambs produced by the JIVET technology in the F2 generation(6 lambs).The number of collected cumulus-oocyte complexes(COCs),the number of maturities,the number of fertilizations,the number of blastocysts,and the number of pregnancies after embryo transfer,the number of litters,and the number of live lambs were collected and recorded.The results showed that:(1)The oocytes obtained from donor sheep of different body weights developed better in vitro,and the blastocyst rate of 10~13 kg group(67.47%)was higher than 13~16 kg group(45.56%);(2)Among the F1 and F2 lambs,the average number of oocytes obtained by the second superovulation of each lamb(34.75;29.67)was lower than the first superovulation(54.50;88.50),F2 lamb The blastocyst rate the second time superovulation(46.43%)was higher than the first time(42.47%);(3)The recipient sheep with grade I luteum had the best transplant effect,and the recipient sheep pregnancy rate(27.27%)and the lambing rate was the highest(133.00%);(4)The pregnancy rate and lambing rate of conventional surgical transplantation(29.55%,115.00%)were higher than laparoscopic transplantation(19.35%;100.00%);1,2 and 3 blastocysts were transplanted,and the pregnancy rate of the recipient sheep increased trend(25.00%;23.64%;50.00%);(6)The gender of lambs produced by JIVET technology should pay more attention in future research.The oocyte of the lamb with genotype FecB(++)had better in vitro development ability than the lamb with genotype FecB(B+).Exp.2 Evaluation study on the production performance of offspring using JIVETThe sheep were selected from the F1 generation lambs of the Booroola Merino sheep and the Xinji fine-wool sheep(14 lambs),the F2 generation lambs produced by the JIVET technology in the F1 generation(15 lambs),the F3 generation lambs produced by the JIVET technology in the F2 generation(6 lambs)and Booroola Merino sheep×Xinji fine-wool sheep crossbred lamb(36 lambs),and the lambs first birth,3 months old,6 months old,1 year old body weight and 3 months old,6 months old,1 year old body size were detected.The results showed that:(1)The lambs produced by JIVET and Booroola Merino sheep×Xinji fine-wool sheep were well-growing.There were significant(P<0.05)or extremely significant(P<0.01)differences in the body weight,body height,rump height,body length,head length,frontal width,tube circumference,chest circumference,chest depth,chest width and waist width.(2)The growth rate was fast from birth to 3 months,and then the growth rate gradually decreased.There was a significant difference in body weight at 3 months(P<0.05).In general,superovulation donor sheep and normal-produced lambs grow well.Using JIVET technology for lamb production has less impact on lamb growth.The above results showed that using JIVET technology,The oocytes obtained from donor sheep of different body weights developed better in vitro;Oocytes obtained by the second superovulation was lower than the first superovulation,F2 lamb The blastocyst rate the second time superovulation was higher than the first time;The recipient sheep with grade I luteum pregnancy rate and the lambing rate was the highest;The pregnancy rate and lambing rate of conventional surgical transplantation were higher than laparoscopic transplantation;1,2 and 3 blastocysts were transplanted,and the pregnancy rate of the recipient sheep increased trend;The gender of lambs produced by JIVET technology should pay more attention in future research.The oocyte of the lamb with genotype FecB(++)had better in vitro development ability than the lamb with genotype FecB(B+);The lambs produced by JIVET and Booroola Merino sheep×Xinji fine-wool sheep were well-growing;The growth rate was fast from birth to 3 months,and then the growth rate gradually decreased;In general,superovulation donor sheep and normal-produced lambs grow well.Using JIVET technology for lamb production has less impact on lamb growth. |
