The Effect Of Feed Intake Level On The Embryonic Survival And Secretion Of IGF-I During Early Pregnancy In Gilts

The present research was conducted to investigate the effect of feed intake level on embryonic survival and secretion of IGF-I during early pregnancy in gilts. A total of 63 Landrace/Yorkshire mixed-breed gilts were randomly allocated to high (H, 2×maintenance feed/d), middle (M, 1.5×maintenance feed/d) or low (L, 0.6×maintenance feed/d) level groups after mating. The gilts were weighed, collected blood samples and slaughtered on dl2, d25, d35 of pregnancy respectively.The results were as follows:1.There were very significant diffenrence in overall weight gain and net weight gain among three levels on dl2, 25, 35 of pregnancy(P<0.01). There was a positive correlation between overall weight gain, or net weight gain and feed intake, showing a very significant linearity change(P<0.01).2.The weight of uterus and its content and the length of tow side uterine horns on d25 of pregnancy were significantly greater in M than in H and L gilts (P<0.05). The weight of uterus and its content and the length of right side uterine horn on d35 of pregnancy were significantly greater in M than in H gilts (P＜0.05).3. Number of live embryos on d12 of pregnancy were significantly greater in M than in H gilts(P<0.05). Total and viable embryonic survival on dl2, 25 35 of pregnancy were significantly greater in M than in H and L gilts (P<0.05).There was not difference between H and L (P>0.05). Embryonic weight on d35 of pregnancy were significantly greater in M than in H gilts(P<0.05), and than in L gilts(P<0.01).4.Serum IGF-I concentration on dl2, 25 of pregnancy was significantly greater in H than in M gilts (P<0.05), and very significantly greater than in L gilts (P<0.01). Serum IGF-I concentration on d25 of pregnancy was significantly greater in M than in L gilts...