| 【Objective】 The purpose of this experiment is to research the effect of BMPR-IB genotypes on the timepoint,reproductive hormones,growth and development of puberty in lambs,and provide the basis for illustrating the biological regulation mechanism of puberty and molecular breeding of prolific sheep.【Methods】 The half shed-feeding prolific Suffolk lambs were used as the experimental group,genomic DNA was isolated from whole blood samples,BMPR-IB genotypes were detected by PCR-RFLP method.The pubertal time of female lambs in the study was determined by ram detecting estrus and the appearance changes of vulva.The difference of pubertal time was analyzed among three BMPR-IB genotype lambs;The contents of MT,Gn RH,FSH,LH,P,E2 and PRL in peripheral blood of female lambs were analyzed in four time points of prepuberty,puberty and metestrus by ELISA method.Furthermore,the characteristics and differences of reproductive hormone secretion among three BMPR-IB genotypes were analyzed.The body weight and body measurement traits of lambs among three BMPR-IB genotypes were measured at a fixed time every month continued to four months.The differences of body weight,body measurement traits,growth and development of lambs with three BMPR-IB genotypes were analyzed at four stages(0d,30 d,60d and 90d).【Results】 The results showed that three BMPR-IB genotypes were found in the prolific Suffolk sheep,and genotype frequencies of ++、B+ and BB were 0.15,0.44 and 0.41,respectively.the average pubertal time was 179 days,the start time of puberty in BB genotype lambs was earlier than that of B+ and ++ genotypes.There was no significant difference in the pubertal time among three genotypes(P>0.05).The secretions of seven reproductive hormones were fluctuated in four time points of prepuberty,puberty and metestrus.The contents of MT and FSH were higher in puberty.The content of PRL in ++ and B+ genotypes was significantly higher than that of BB genotypes in 1st day of metestrus(P<0.05).The content of LH in BB genotype was significantly higher than that of B+ and ++ genotypes in 2nd day of metestrus(P<0.05).On 0 day,The body height of ++ genotype was significantly higher than that of BB genotype(P<0.05),and the chest circumference of B+ genotype was significantly higher than that of BB genotype(P<0.05).At 0d,60 d and 90 d,the body skew length and body straight length of ++ genotype were significantly higher than those of BB genotype(P<0.05).At 0d,30 d,60d and 90 d, the body weight,average daily gain and cumulative growth of ++ genotype were higher than those of BB genotype.【Conclusion】 The start time of puberty,secretion of reproductive hormone,growth and development were affected by different BMPR-IB genotypes in the half shed-feeding prolific Suffolk lambs.The contents of FSH and E2 were increased in puberty.Because of BMPR-IB gene mutation,the start time of puberty in mutant was earlier than wild type,and the contents of MT,Gn RH,P,E2 and PRL in mutant were increased.However,the early growth and development of BB homozygous lambs was slower than that of wild type. |
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