Biomaterial Database

Developmental changes in insulin-like growth factor (IGF)-I and -II mRNA abundance in extra-embryonic membranes and small intestine of avian embryos. 2009

D M Karcher, and J N Fleming-Waddell, and T J Applegate

Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA. dkarcher@msu.edu

OBJECTIVE Numerous researchers have evaluated the insulin-like growth factors (IGF) influence on mammalian fetal development. Although IGF has been explored in the avian system, questions remain on the role of IGF in avian development. Therefore, the current study evaluated the mRNA abundance of IGF in the amnion and allantoic membranes and developing small intestine in the chicken, duck, and turkey during the incubation and post-hatch period. METHODS Broiler, duck, and turkey eggs were incubated with small intestinal, allantoic, and amniotic membranes collected in the final days of incubation and 1 week post-hatch. RNA was extracted using Trizol and qRT-PCR was utilized to compare differences during embryo development within and across species. RESULTS The expression of the IGF mRNA varied between species in the final days of incubation in the amniotic and allantoic membranes. The turkey had higher (0.38-1.72 log) transcript abundance of IGF-I and IGF-II in the amnion and allantois compared to the chicken and duck. Evaluating the mRNA abundance within the chicken duodenum, jejunum, and ileum, the duodenum had the lowest expression of IGF-I and IGF-II (P<0.05) at day -4 of incubation compared to the jejunum and ileum. Focusing on differences in jejunal IGF expression among the three species, the turkey had the lowest IGF-I abundance at day -4 of incubation and highest IGF-I abundance at day of hatch (P<0.05). Transcript abundance of both IGF-II and IGF-R was highest in the turkey at day of hatch and day 1 post-hatch compared to the duck and chicken. The whole tissue versus the mucosal expression of the IGF mRNA abundance was evaluated during the post-hatch period. Duodenal, jejunal, and ileal segments had higher IGF-I transcript abundance (P<0.05) at day 1, day 3, and day of hatch, respectively. No differences were observed between segment and mucosa for IGF-II in the post-hatch period. The duodenal and jejunal mucosa IGF-R transcript abundance was greater (P<0.05) at day of hatch compared to the intestinal segment. The duck IGF mRNA in the jejunal mucosa was higher than the whole segment and decreased from day of hatch to day 3 post-hatch while the IGF mRNA abundance increased in the whole segment during the same time period. The turkey IGF-I transcript abundance decreased in both the segment and mucosa following hatch while the IGF-II mRNA expression increased by 1.5 logs from hatch to day 1 post-hatch. CONCLUSIONS The transcript abundance of the IGF axis in the extra-embryonic membranes and gastrointestinal tissue of the developing chicken, duck, and turkey are influenced by embryonic age and species. A better understanding of the IGF axis in the small intestine during embryonic development may allow for increasing the optimal growth of both the gastrointestinal tract and the neonate.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D007334	Insulin-Like Growth Factor I	A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on GROWTH HORMONE. It is believed to be mainly active in adults in contrast to INSULIN-LIKE GROWTH FACTOR II, which is a major fetal growth factor.	IGF-I,Somatomedin C,IGF-1,IGF-I-SmC,Insulin Like Growth Factor I,Insulin-Like Somatomedin Peptide I,Insulin Like Somatomedin Peptide I
D007335	Insulin-Like Growth Factor II	A well-characterized neutral peptide believed to be secreted by the LIVER and to circulate in the BLOOD. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on SOMATOTROPIN. It is believed to be a major fetal growth factor in contrast to INSULIN-LIKE GROWTH FACTOR I, which is a major growth factor in adults.	IGF-II,Multiplication-Stimulating Activity,Somatomedin MSA,IGF-2,Insulin Like Growth Factor II,Insulin-Like Somatomedin Peptide II,Multiplication-Stimulating Factor,Somatomedin A,Factor, Multiplication-Stimulating,Insulin Like Somatomedin Peptide II,Multiplication Stimulating Activity,Multiplication Stimulating Factor
D007421	Intestine, Small	The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.	Small Intestine,Intestines, Small,Small Intestines
D007583	Jejunum	The middle portion of the SMALL INTESTINE, between DUODENUM and ILEUM. It represents about 2/5 of the remaining portion of the small intestine below duodenum.	Jejunums
D004372	Ducks	A water bird in the order Anseriformes (subfamily Anatinae (true ducks)) with a broad blunt bill, short legs, webbed feet, and a waddling gait.	Duck
D004386	Duodenum	The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.	Duodenums
D004625	Embryo, Nonmammalian	The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.	Embryonic Structures, Nonmammalian,Embryo, Non-Mammalian,Embryonic Structures, Non-Mammalian,Nonmammalian Embryo,Nonmammalian Embryo Structures,Nonmammalian Embryonic Structures,Embryo Structure, Nonmammalian,Embryo Structures, Nonmammalian,Embryo, Non Mammalian,Embryonic Structure, Non-Mammalian,Embryonic Structure, Nonmammalian,Embryonic Structures, Non Mammalian,Embryos, Non-Mammalian,Embryos, Nonmammalian,Non-Mammalian Embryo,Non-Mammalian Embryonic Structure,Non-Mammalian Embryonic Structures,Non-Mammalian Embryos,Nonmammalian Embryo Structure,Nonmammalian Embryonic Structure,Nonmammalian Embryos,Structure, Non-Mammalian Embryonic,Structure, Nonmammalian Embryo,Structure, Nonmammalian Embryonic,Structures, Non-Mammalian Embryonic,Structures, Nonmammalian Embryo,Structures, Nonmammalian Embryonic
D005321	Extraembryonic Membranes	The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.	Fetal Membranes,Extra-Embryonic Membranes,Extra Embryonic Membranes,Extra-Embryonic Membrane,Extraembryonic Membrane,Fetal Membrane,Membrane, Extra-Embryonic,Membrane, Extraembryonic,Membrane, Fetal,Membranes, Extra-Embryonic,Membranes, Extraembryonic,Membranes, Fetal
D000482	Allantois	An extra-embryonic membranous sac derived from the YOLK SAC of REPTILES; BIRDS; and MAMMALS. It lies between two other extra-embryonic membranes, the AMNION and the CHORION. The allantois serves to store urinary wastes and mediate exchange of gas and nutrients for the developing embryo.	Allantoic Membrane,Membrane, Allantoic