Thesis (M.N.A.S.)--Missouri State University, 2008. / "May 2008." Includes bibliographical references (leaves 43-47). Also available online.

Hierdie studie het ten doel gehad om die effekte van Se en β-karoteentoediening op vit A, vit E, konsepsietempo en progesteroonvlakke tydens embrio-oorplasings in ontvangerkoeie te ondersoek. Die effekte van die verskillende faktore op mekaar sou ook bepaal word. In Totaal van 142 multipare koeie wat in vier groepe verdeel is, was as ontvangers vir die studie gebruik. Die groepe was as volg behandel: Groep 1 (35 koeie), 50 mg Se en 1500 mg vit E intramuskulêr 6 en 3 weke voor die oorplasings; Groep 2 (36 koeie), 300 mg l1-karoteen per os per bees per dag vanaf 6 weke voor die oorlasings; Groep 3 (36 koeie), vit E/Se en β-karoteen soos in Groepe 1 en 2 respektiewelik; Groep 4 (35 koeie) negatiewe kontrole groep met geen behandeling nie. Elke ontvanger het 6 weke voor oorplasing vit ADE oraal ontvang. Embrios is na 20, 19, 19 en 18 ontvangers van Groepe 1, 2, 3 en 4 onderskeidelik oorgeplaas. Bloedmonsters is van elke dier vir ontledings in die middel van die oorplantingsperiode getrek. Die toediening van Se was hoogs betekenisvol met RBS GSH-Px aktiwiteit gekorreleer R2 = 0,32960, (n = 136, P = 0,0000). Die toediening van β-karoteen was ook hoogs betekenisvol gekorreleer met die RBS GSH-Px aktiwiteit, R2 = 0,18950, (n=136, P< 0,0000). Die RBS GSH-Px aktiwiteit was 7,49,6,61,10,75 en 4,5 EE 11x1010 RBS vir Groepe 1, 2, 3 en 4 onderskeidelik. Groepe 1 en 3,1 en 4, 2 en 3, 2 en 4, en 3 en 4 het betekenisvol van mekaar verskil maar nie Groepe 1 en 2 nie. Daar was geen verband tussen β-karoteen plasmavlakke en RBS GSH¬Px aktiwiteit nie. Die orale toediening van β-karoteen het plasmavlakke duidelik laat styg en was betekenisvol met die β-karoteen plasmavlakke gekorreleer R2 = 0,09296, (n = 134, P=O,0003). Die groepe wat β-karoteen ontvang het, Groepe 2 en 3, se plasmavlakke was merkbaar hoër as die van Groepe 1 en 4 wat niks ontvang het nie. Die groep se waardes was 8,72, 10,13, 9,53 en 8,50 µmol/l vir Groepe 1, 2, 3 en 4 respektiewelik. Groepe 1 en 2, 2 en 4, en 3 en 4 het betekenisvol van mekaar verskil (P=0,0021) maar nie Groepe 1 en 3, en 1 en 4 nie. Daar was 'n positiewe korrelasie tussen die toediening van vit E/Se en die a¬tocoferol plasmavlakke, R2 = 0,06344, (n = 134, P=0,0033). Daar was egter geen aanduiding van 'n verband tussen RBS GSH-Px aktiwiteit en α-tocoferol plasmavlakke nie. Daar was wel In betekenisvolle korrelasie tussen α-tocoferol en β-karoteen plasmavlakke (P=0,0001). Die groepswaardes was 11,90, 10,59, 11,67 en 10,56 vir Groepe 1, 2, 3 en 4 onderskeidelik. Groepe 1 en 2, en 1 en 4 het betekenisvol van mekaar verskil (P=0,0334) maar nie die ander groepe, Groepe 1 en 3, 2 en 3, 2 en 4, en 3 en 4 nie. Die korrelasie tussen die toediening van Se en die retinol plasmavlakke was nie statisties betekenisvol nie (P=0,0671) maar tussen RBS GSH-Px aktiwiteit en retinol plasmavlakke was dit wel betekenisvol R2 = 0,03086, (n = 133, P=0,0431). Daar was ook In waarskynlike korrelasie tussen die toediening van β-karoteen en die retinol plasmavlak (P=0,0835) maar geen korrelasie tussen β-karoteen plasmavlakke en retinol plasmavlakke nie. Die groepwaardes was 1,068, 1,065, 1,154 en 1,026 µmol/l vir Groepe 1, 2, 3 en 4 onderskeidelik. Die dragtigheidstempo na die oorplasing van embrios was 50,0%, 47,4%, 31,5% en 27,8% vir Groepe 1, 2, 3 en 4 onderskeidelik. Die verskille was nie betekenisvol nie. Daar was 'n negatiewe korrelasie tussen die β-karoteen plasmavlakke en progesteroon plasmavlakke vir die eerste 5-9 dae van die estrussiklus. Retinol plasmavlakke en progesteroon plasmavlakke was wel positief gekorreleer (P=O,0317). Die groepswaardes was 5,67, 2,90, 4,28 en 5,60 µmol/l vir Groepe 1, 2, 3 en 4 onderskeidelik. RBS GSH-Px was betekenisvol gekorreleer met corpus luteum grootte maar corpus luteum grootte was nie met progesteroon waardes gekorreleer nie. Daar was geen statistiese verskille tussen die groepe ten opsigte van estruslengte en die tydsduur tussen prostaglandientoediening en estrus nie. Op individuele basis was daar wel In betekenisvolle korrelasie van β-karoteen plasmavlak met beide estruslengte (P=O,0298) en die tydsduur tussen prostaglandientoediening en estrus (P=0,0130). Estruslengte en die tydsduur tussen prostaglandien en estrus was ook betekenisvol met mekaar gekorreleer (P < 0,0000). / This study addressed some of the effects that selenium and β-carotene administration have on vit A, vit E, conception rates, progesterone levels, oestrus length, interval from PG to oestrus and corpus luteum size in embryo recipients. A total of 142 multiparous cows asigned to 4 test groups, were used as recipients in this study. Group 1 (35 cows) received 50 mg Se and 1500 mg vit E intramuscularly 6 and 3 weeks before transfer, Group 2 (36 cows) received 300 mg β-carotene orally per cow per day starting 6 weeks prior to transfer, Group 3 (36 cows) received both vit ElSe and β-carotene as per Group 1 and 2 and Group 4 (35 cows) was a negative control, with no treatment. All recipients received vit ADE orally 6 weeks before transfers. Embryos were transferred to 20, 19, 19, and 18 recipients of the Groups 1, 2, 3 and 4 respectively. Blood for analysis was drawn from all the recipients in the middle of the transferal week, being day 3 of the 5-day period. The administration of selenium was highly significantly correlated with the corresponding RBS GSH-Px activity R2 = 0,3290, (n = 135, P < 0,0000). The β-¬carotene administration was also highly significantly correlated with the RBS GSH¬Px activities R2 = 0,18950, (n = 136, P < 0,0000). However, there were no correlation between the β-carotene plasma levels and that of the RBS GSH-Px activities. The RBS GSH-Px were 7,49, 6,61, 10,75 and 4,5 Enzyme Units 11x1010 RBS for Groups 1, 2, 3 and 4 respectively. Groups 1 and 3, 1 and 4, 2 and 3, 2 and 4, and 3 and 4 differ significantly from each other but not Groups 1 and 2. There were no connection between B-carotene plasma levels and RBS GSH-Px activities. The treatment of β-carotene itself was succesful and was significantly correlated with the resulting β-carotene plasma levels R2 = 0,09296, (n = 134, P = 0,0033). The β-carotene plasma levels of the groups that received β-carotene, Groups 2 and 3, were noticeably higher than those of Group 1 and 4, which did not receive β-carotene. The values were 8,72, 10,13, 9,53 and 8,5 µmol/l for Groups 1, 2, 3 and 4 respectively. Groups 1 and 2, 2 and 4, and 3 and 4 differed significantly from one another (P = 0,0021) but not those of Groups 1 and 3, and 1 and 4. There was a positive correlation between the administration of Se and the retinol plasma levels (P = 0,0671) and a positive significant correlation between the RBS GSH-Px and the retinol plasma levels R2 = 0,03086, (n = 133, P = 0,0431). There was also a positive correlation between the administration of β-carotene and the retinol plasma levels (P = 0,0835) but no correlation between β-carotene plasma levels and retinol plasma levels. The values were 1,068, 1,065, 1,154 and 1,026 µmol/ for Groups 1, 2, 3 and 4 respectively. The pregnancy rate after embryo transferal were 50%, 47,4%, 31,5% and 27,8% for Groups 1, 2, 3 and 4 respectively. The differences were not significant. There was a negative correlation between β-carotene plasma levels and progesterone plasma levels for the first 5 to 9 days of the oestrus cycle. Retinol plasma levels however were significantly correlated with progesterone plasma levels (P = 0,0317). The progesterone levels were 5,67, 2,90, 4,28 and 5,60 µmol/ for Groups 1, 2, 3 and 4 respectively. The RBS GSH-Px activity was significantly correlated with corpus luteum size (P = 0,0445) but corpus size was not correlated with progesterone values. There were no statistical differences amongst the groups, between oestrus length and the interval from prostaglandin to oestrus. However on an individual basis there was a significant correlation between β-carotene plasma levels and both the oestrus length (P = 0,0298) and the interval from prostaglandin to oestrus (P = 0,0130). Oestrus length and the interval from prostaglandin to oestrus were also significantly correlated with each other (P < 0,0000). / Dissertation (MMedVet)--University of Pretoria, 2000. / Production Animal Studies / MMedVet / Unrestricted

Indiana University-Purdue University Indianapolis (IUPUI) / During pregnancy, maternal liver exhibits robust growth to meet the metabolic demands of the developing placenta and fetus. Although hepatocyte hypertrophy and hyperplasia are seen in the maternal liver, the molecular and cellular mechanisms mediating the maternal hepatic adaptations to pregnancy is poorly understood. Previous microarray analysis revealed a most upregulated gene named Ascl1, a transcription factor essential for neural development, in the maternal liver at mid-gestation. The aims of the study were to (1) validate the activation of Ascl1 gene; (2) identify Ascl1-expressing cells; and (3) determine the fate of Ascl1-expressing cells, in the maternal liver during the course of gestation. Timed pregnancy was setup in mice and the maternal livers were collected at various stages of gestation. Maternal hepatic Ascl1 mRNA expression was evaluated by qRT-PCR and northern blotting. The results demonstrated that the transcript level of maternal hepatic Ascl1 is exponentially increased during the second half of pregnancy in comparison with a non-pregnant state. Using a Ascl1-GFP mouse model generated by others to monitor the behavior of neural progenitor cells, we found that maternal hepatic Ascl1-expressing cells are non-parenchymal cells, very small in size, and expanding during pregnancy. To map the fate of this cell population, we generated an in vivo tracing mouse model named Ascl1-CreERT2/ROSA26-LacZ. Using this model, we permanently labeled maternal hepatic Ascl1-expressing cells at midgestation by giving tamoxifen and analyzed the labeled cells in the maternal liver prior to parturition. We observed that the initial small Ascl1-expressing cells undergoing expansion at mid-gestation eventually became hepatocyte-like cells at the end stage of pregnancy. Taken together, our findings strongly suggest that Ascl1-expressing cells represent a novel population of hepatic progenitor cells and they can differentiate along hepatocyte lineage and contribute to pregnancy-induced maternal liver growth. Further studies are needed to firmly establish the nature and property of maternal hepatic Ascl1-expressing cells. At this stage, we have gained significant insights into the cellular mechanism by which the maternal liver adapts to pregnancy.