摘要
This study investigated the effects of hormonal status and metabolic changes of restricted ewes during late pregnancy on the ovine fetus growth and development. One hundred Mongolian ewes, synchro- nized for oestrus and mated, were divided into three groups and offered 0.175 MJME·kgw-0.75·d-1 (Re- stricted Group 1, RG1), 0.33 MJME·kgw-0.75·d-1 (Restricted Group 2, RG2) and ad libitum access to feed (Control Group, CG) during their late pregnancy respectively. The results suggested that with the sup- ply of exogenous energy decreasing during late pregnancy, maternal body weight and net body weight loss in RG2 and RG1 were lower than those of CG (P<0.01). The insulin and IGF-1 concentrations of ewes in RG2 and RG1 tended to be lower than those of CG (P>0.05), but the GH concentrations in RG2 and RG1 were enhanced and there was significant difference between RG1 and CG on d 120 of gesta- tion (P<0.05). The glucose concentration of ewes in RG2 and RG1 was decreased throughout the feed restriction period, and the differences were observed between RG1 and CG on d 120 of gestation (P<0.05). In addition, the nonesterified fatty acid (NEFA) and total amino acid (TAA) concentrations of ewes in RG2 tended to increase, but there was no significant difference (P>0.05). However, the NEFA and FAA concentrations of ewes in RG1 were reduced from d 90 to d 120 of gestation, then enhanced from d 120 to d 140 of gestation. During the late pregnancy, with the supply of nutrition decreasing, the negatively physiological and biochemical maternal reactions to restriction became worse, which sig- nificantly reduced the average lamb birth weight and daily growth rate of fetus in RG2 (P<0.05) and RG1 (P<0.01).
This study investigated the effects of hormonal status; metabolic changes of restricted ewes during late pregnancy on the ovine fetus growth; development. One hundred Mongolian ewes, synchronized for oestrus; mated, were divided into three groups; offered 0.175 MJME·kgw[0.75]·d[1] (Restricted Group 1, RG1), 0.33 MJME·kgw[0.75]·d[1] (Restricted Group 2, RG2); ad libitum access to feed (Control Group, CG) during their late pregnancy respectively. The results suggested that with the supply of exogenous energy decreasing during late pregnancy, maternal body weight; net body weight loss in RG2; RG1 were lower than those of CG (Ps0.01). The insulin; IGF-1 concentrations of ewes in RG2; RG1 tended to be lower than those of CG (P>0.05), but the GH concentrations in RG2; RG1 were enhanced; there was significant difference between RG1; CG on d 120 of gestation (P<0.05). The glucose concentration of ewes in RG2; RG1 was decreased throughout the feed restriction period,; the differences were observed between RG1; CG on d 120 of gestation (P<0.05). In addition, the nonesterified fatty acid (NEFA); total amino acid (TAA) concentrations of ewes in RG2 tended to increase, but there was no significant difference (P>0.05). However, the NEFA; FAA concentrations of ewes in RG1 were reduced from d 90 to d 120 of gestation, then enhanced from d 120 to d 140 of gestation. During the late pregnancy, with the supply of nutrition decreasing, the negatively physiological; biochemical maternal reactions to restriction became worse, which significantly reduced the average lamb birth weight; daily growth rate of fetus in RG2 (P<0.05); RG1 (P<0.01).
基金
Supported by the National Natural Science Foundation ( NSFC) of China (Grant Nos. 30460095 and 30360074)
Doctoral Fund of Ministry of Education of China (20060129008)
Scientific Research Foundation for Doctor of Inner Mongolia Agricultural University (BJ06-36)