| This paper mainly investigated the effect of maternal undernutrition during late pregnancy on the ovine fetal growth and development,subsequent compensatory growth of postnatal lambs and the potential mechanisms involved in order to apply the ability of compensatory growth scientifically and supply references for feeding and management system of husbandy.Part 1 Effect of undernutrition during late pregnancy on the ewesThis study focused on the effect of undernutrition during late pregnancy on the ewes.100 Mongolia ewes, which were synchronized for oestrus and mated at the same day, were selected and divided into three groups offered 0.175 MJME·kgw-0.75·d-1 (Restricted Group1; RG1), 0.33 MJME·kgw-0.75·d-1 (Restricted Group2; RG2) and voluntary intake (Control Group; CG) during their late pregnancy (90 days) respectively. The results indicated that body weights of ewes in RG2 and RG1 were significantly (p<0.01) reduced when compared to those of the CG during feed restricted period. With the nutrients supply decreasing, maternal net body weight loss of ewes in RG2 and RG1 were 6.61,9.66 kg (p<0.01)and when expressed as a percentage of maternal net body weight at the beginning of restriction , tissues of the ewes in RG2 and RG1 were mobilized 16.35% and 24.04% respectively, and were significant higher(p<0.01)than that of CG. The carcass weights of ewes in RG2(p<0.05) and RG1 (p<0.01)were reduced, and protein(p<0.01) and fat (p<0.01)of meat were mobilized greatly when compared to those of CG. In addition, with pregnancy progressed, the GH concentration of the ewes in RG2 and RG1 showed the trend to decrease respectively compared to CG , and the GH concentrations of RG1 was significant lower than CG(p<0.05)at 120 days. The INS and IGF-1 concentration of ewes in RG2 and RG1 tended to be lower than those of CG, but the difference were not significant(p>0.05). The GLU concentration of ewes in RG2 and RG1 decreased with the nutrients supply decreasing during restriction, and the differences (P<0.05) were observed between RG1 and CG at 120 days. The NEFA and FAA concentration of ewes in RG2 were rising during late pregnancy, but there were not significant difference(p>0.05).However, the NEFA and FAA concentration of ewes... |
