D. Davachi - Academia.edu (original) (raw)

Papers by D. Davachi

The goal of this study was to investigate the effect of fish oil–supplemented diet on fresh and p... more The goal of this study was to investigate the effect of fish oil–supplemented diet on fresh and post-thaw semen quality and sperm lipid composition in bulls. Bulls were randomly assigned to two groups (n ¼ 6). Six bulls were used as the control group and six received the fish oil (1.2% dry matter of total diet) for 11 weeks. Semen was individually collected from each bull and frozen biweekly. Semen volume, sperm concentration, viability, progressive motility, and fatty acid profile of sperm were measured in 1st, 3rd, 5th, 7th, 9th, and 11th week of experiment. Viability, progressive motility, and fatty acid profile of post-thaw sperm were also measured in 3rd, 5th, 9th, and 11th week of experiment. Data were analyzed with using Proc GLM or MIXED (for repeated measurement data) in SAS program. The fish oil–supplemented diet increased the semen volume and sperm concentration. The fish oil–supplemented diet also altered the viability, progressive motility, and fatty acid profile of fresh and post-thaw sperm. In conclusion, feeding a fish oil– enriched diet via alteration of fatty acid profile of sperm lipid could improve in vitro quality of fresh and post-thaw sperm in Holstein bulls.

The present study was designed to determine the effect of three different extenders on ram sperm ... more The present study was designed to determine the effect of three different extenders on ram sperm quality during a freeze-thawing procedure using flow cytometric and microscopic evaluations. Several in vitro qualitative analyses of postthawed sperm parameters including motility and velocity parameters, plasma membrane functionality, total abnormality, capacitation status, acrosome integrity, mitochondrial activity and apoptosis features were considered. In the breeding season, seven ejaculates from each Zandi ram were collected routinely twice a week. Following semen collection, samples were pooled and equally divided into three aliquots. Each aliquot was diluted and frozen with one of the following extenders:

The central role of the oviduct, as the site of zona pellucida (ZP) maturation, fertilization and... more The central role of the oviduct, as the site of zona pellucida (ZP) maturation, fertilization and
early embryogenesis, has been recognized. The objective of this study was to investigate
whether ampullary and isthmic derived epithelial cells have different effects on in vitro ZP
hardening, in vitro fertilization (IVF) and in vitro culture (IVC) of the resulting embryos.
Cumulus oocyte complexes (COCs) were matured in a coculture system with ampullary/
isthmic epithelial cells, TCM199 supplemented with insulin-like growth factor I (IGF-I) and
epithelial derived growth factor (EGF) (GF treated group), conditioned media produced using
ampullary (ACM), isthmic (ICM), COCs + ampullary, and COCs + isthmic epithelial cells,
contactless culture system, oviductal
fluid, GF + ACM/ICM, and drops of TCM199 (control),
for 24 h. The matured oocytes were randomly divided into two groups: Group I was subjected
to ZP digestion; Group II underwent IVF. The duration of the ZP digestion, in a coculture
system with ampullary epithelial cells (AE) was significantly increased ( p < 0.05), compared
with other groups. Penetrated oocytes and monospermic fertilization were significantly
increased ( p < 0.05) in the AE group. The mean number of spermatozoa per penetrated
oocyte was reduced dramatically for the AE group ( p < 0.05). A significant increase ( p < 0.05)
in the embryo development was observed in all treated groups, compared to the control.
Results revealed that epithelial cells harvested from the ampullary segment of the oviduct
had in vitro specialized role in ZP hardening and have subsequent IVF and IVC outcomes.

Iranian Journal of Biotechnology, 2014

Background: Chronic active adrenocorticotropin hormone (ACTH) immunization of ewes (with a previo... more Background: Chronic active adrenocorticotropin hormone (ACTH) immunization of ewes (with a previous history of immunization) resulted in elevated titres of antibody against ACTH, which induced a reduction in circulating levels of cortisol. Objectives: The aim of the present study was to investigate: a) the influence of active immunization against ACTH on milk production of the ewe as assessed by milk intake of the lamb measured with two different methods, b) whether the stimulation of levels of β-end and α-MSH in the circulation can result in a similar increase in the expression of these peptides in the milk of the lactating ewe, thereby producing a milk with high analgesic properties. Materials and Methods: Ten primiparous Merino ewes (4-5 years old) during their first 5 weeks of lactation were used in the experiment. Milk intake of each lamb can be used to give the ewe's milk yield per unit time, and this can be used for secretion of peptides over time. This was determined by two different techniques: the deuterium oxide method and the weigh-suck-weigh method. β-end, α-MSH and cortisol were measured in blood samples and β-end, α-MSH in milk samples using RIAs (Radio Immune Assay). Results: Plasma β-end and α-MSH in ACTH-immune animals increased to 3 and 38-fold respectively, although the level of α-MSH is most likely exaggerated by the presence of α-MSH antibodies in the ACTH immune plasma, as α-MSH comprises the N-terminal 13 amino acids of ACTH. Antibodies also were detected in the plasma of lambs of immune ewes after birth, at levels, which were comparable to those measured in the ewes during the period of colostrum production and thereafter decreased to much lower levels by the end of the experiment. Plasma β-end and α-MSH in the lambs of immune ewes were significantly higher than those measured in the lambs of control ewes. Conclusions: The immunization procedure had no effect on feed intake, live weight gain and milk production of ewes nor was the growth rate or milk intake of the lambs altered. The expression of β-end and α-MSH in milk was also unaffected by the high concentrations of these hormones in the circulation of immune ewes.

Iranian Journal of Biotechnology, 2014