Little is known about the genetics controlling the rate of embryonic development in salmonids, despite the fact that this trait plays an important role in the life history of wild and cultured stocks. We investigated the genetics of embryonic development rate by performing an analysis of quantitative trait loci (QTL) on two families of androgenetically derived doubled haploid rainbow trout produced from a hybrid of two clonal lines with divergent embryonic development rates. A total of 170 doubled haploid individuals were genotyped at 222 marker loci [219 amplified fragment length polymorphism (AFLP) markers, 2 microsatellites, and p53]. A genetic linkage analysis resulted in a map consisting of 27 linkage groups with 21 of the markers remaining unlinked at a minimum LOD of 3.0 and maximum theta of 0.40. Eight of these linkage groups were matched to published rainbow trout linkage groups. Composite interval mapping (CIM) revealed evidence for two QTL influencing time to hatch, and suggestive evidence for a third. These QTL accounted for a total of 24.6% of the variation in time to hatch. One of these QTL had a large effect on development rate, especially in one family of doubled haploids, in which it explained 25.6% of the variance in time to hatch. QTL influencing embryonic length and weight at the commencement of exogenous feeding were also identified. The QTL with the strongest effect on embryonic length (lenR13) mapped to the same position as the QTL with the strongest effect on time to hatch (tthR13), suggesting a single QTL may have a pleiotropic effect on both these traits. These results suggest that the use of clonal lines with a doubled haploid crossing design is an effective way of analyzing the genetic basis of complex traits in salmonids.

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The study examined the effects of different environmental stress on developmental competence and the relative abundance (RA) of various gene transcripts in oocytes and embryos of buffalo. Oocytes collected during cold period (CP) and hot period (HP) were matured, fertilized and cultured in vitro to blastocyst hatching stage. The mRNA expression patterns of genes implicated in developmental competence (OCT-4, IGF-2R and GDF-9), heat shock (HSP-70.1), oxidative stress (MnSOD), metabolism (GLUT-1), pro-apoptosis (BAX) and anti-apoptosis (BCL-2) were evaluated in immature and matured oocytes as well as in pre-implantation stage embryos. Oocytes reaching MII stage, cleavage rates, blastocyst yield and hatching rates increased (P \ 0.05) during the CP. In MII oocytes and 2-cell embryos, the RA of OCT-4, IGF-2R, GDF-9, MnSOD and GLUT-1 decreased (P \ 0.05) during the HP. In 4-cell embryos, the RA of OCT-4, IGF-2R and BCL-2 decreased (P \ 0.05) in the HP, whereas GDF-9 increased (P \ 0.05). In 8-to 16-cell embryos, the RA of OCT-4 and BCL-2 decreased (P \ 0. 05) in the HP, whereas HSP-70.1 and BAX expression increased (P \ 0.05). In morula and blastocyst, the RA of OCT-4, IGF-2R and MnSOD decreased (P \ 0.05) during the HP, whereas HSP-70.1 was increased (P \ 0.05). In conclusion, deleterious seasonal effects induced at the GVstage carry-over to subsequent embryonic developmental stages and compromise oocyte developmental competence and quality of developed blastocysts.

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Status of blood minerals and their absorption by neonate calves as influenced by fat soluble vitamins supplementation in their respective mothers, mineral supplementation in calves themselves has been evaluated. The objective was to know the impact of antioxidant vitamin supplementation to advance pregnant buffaloes, on enhanced acquired immunity during first few hours after birth, in relation to weight gain in buffalo calves. Advance pregnant buffaloes (n = 30) consisting of average body weight of 550±15 kg and of 4-6 parity were fed on 25 kg green (green Jawar-Sorghum bicolor), 2-3 kg wheat straw and 3-4 kg concentrate mixture individually per day. Intramuscular injections of vitamin triplex A D 3 E consisting of -2,500,000 IU of vit A -Palmitate; 2,500,000 IU of vitamin D 3 and 1,000 IU of vit E (dl-alpha tocopherol acetate) were given per dose, a month prior to parturition, twice at 15 days interval to 15 dams. Rest of the 15 pregnant buffaloes served as negative controls. Secretion of immune proteins, immunoglobulin (Ig) enhanced by 80% in colostrum. The blood serum levels of Zn, Cu, Ca, Mg were measured from birth to 90 days in calves. A significant (p<0.05) difference between the blood serum Zn levels of calves born to vitamin supplemented and non-supplemented dams was measured and a positive correlation between blood serum Zn levels and injections of vitamins was identified. Association of Zn and Cu with passive immunity status has been identified in these calves. A significant positive correlation between Zn and Cu was also identified which showed a change under the impact of vitamin supplementation in buffaloes. The study signifies the role of micronutrients supplementation in dams prior to parturition, in calf immunity development. The study indicates significant mineral -vitamins interactions during this process.

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