本试验旨在研究妊娠后期营养限饲对蒙古绵羊体贮动员及其胎儿生长发育的影响。选择健康的蒙古绵羊35只(经同期发情受孕),在妊娠90 d时选择6只母羊进行屠宰,其余按体重随机分为3组,分别为自由采食组[C组,代谢能(ME)日均采食量为0.670 MJ/(kg W^0.75·d),n=8]、限饲1组[R1组,ME日均采食量为0.175 MJ/(kg W^0.75·d),n=12]、限饲2组[R2组,ME日均采食量为0.330 MJ/(kg W^0.75·d),n=9],试验至妊娠140 d结束,每组再选择6只母羊进行屠宰。结果表明:妊娠140 d,R1组母体净失重,胴体重,肉中干物质、粗脂肪、粗蛋白质、粗灰分含量,血浆葡萄糖(GLU)、总氨基酸(TAA)浓度极显著低于C组(P<0.01),而非酯化脂肪酸(NEFA)、β-羟丁酸(BHBA)浓度极显著高于C组(P<0.01);R2组母羊净失重,胴体重,肉中干物质、粗脂肪含量及血浆GLU、TAA浓度极显著低于C组(P<0.01),而血浆NEFA浓度极显著增加(P<0.01)。母羊失重导致R1组和R2组胎儿重均极显著低于C组(P<0.01),而且R1组体长(P<0.05)、胸围(P<0.05)、腹围(P<0.05)和曲冠臀长(P<0.01)显著或极显著低于C组。总之,妊娠后期随着营养水平的降低,限饲ME日均采食量为0.330 MJ/(kg W^0.75·d)时,母体的缓冲保护系统仍对胎儿有一定的作用,而继续限饲至ME日均采食量为0.175 MJ/(kg W^0.75·d)时,母体的营养缓冲系统可能已被打破,严重影响到其胎儿的生长发育。

This study was carried out to investigate the effects of dietary restriction on mobilization of Mongolia ovine maternal reserves and their fetal growth during late gestation. Thirty five Mongolia ewes mated at a synchronized estrus were selected. Six ewes were slaughtered at 90 days of gestation and the remained ewes were allocated to three groups: ad libitum group [group C, average daily ME intake=0.670 MJ/(kg W^0.75·d), n=8], restricted group 1 [group R1, average daily ME intake=0.175 MJ/(kg W^0.75·d), n=12] and restricted group 2 [group R2, average daily ME intake=0.330 MJ/(kg W^0.75·d), n=9]. At 140 days of gestation, six ewes in each group were slaughtered. The results showed as follows: at 140 days of gestation, maternal net body weight (BW) lose, carcass weight, dry matter, ether extract, crude protein and ash in meat, as while as the concentrations of glucose (GLU) and total amino acid (TAA) in plasma of ewes in group R1 were significantly lower than those in group C (P<0.01), but the concentrations of non-esterified fatty acid (NEFA) and β-hydroxybutyric acid (BHBA) in plasma were significantly higher than those in group C (P<0.01); compared with group C, maternal net BW lose, carcass weight, dry matter and ether extract in meat, as while as the concentrations of GLU and TAA in plasma of ewes in group R2 were significantly decreased (P<0.01), and plasma NEFA concentration was significantly increased (P<0.01). The maternal BW lose led to significant reductions of fetal weight both in groups R1 and R2 (P<0.01), and body length (P<0.05), thoracic girth (P<0.05), abdomen circumference (P<0.05) and curved crown-rump length (P<0.01) in group R1. In conclusion, with the decrease of dietary nutrient level during late gestation, the maternal protective buffer system is still playing major roles when average daily ME intake=0.330 MJ/(kg W^0.75·d), but the system may be destroyed when average daily ME intake=0.175 MJ/(kg W^0.75·d), which results in serious impacts on fetal growth and development.