الفهرس 
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Abstract
The objectives of the current study were to:1- Perform an expression analysis for IL 2, IL 6, IL 12 and HSP 70 genes in Barki and Rahmani sheep in summer and winter seasons in two distinct locations (Alexandria zone vs Matrouh zone).
2- Estimation the genetic polymorphism between studied breeds.
3- Assess the changes in thermo-physiological parameters and biochemical blood components under heat stress and thermoneutral conditions.
4- Estimation the correlations between all gene expression, blood constituents measurements and physio-thermal parameters in addition to climatic conditions The experiments were carried out in two Special time spans coinciding with the coldest and
hottest periods of year viz. mid-winter (January) and mid-summer (August). The animals were raised under similar management conditions and were observed throughout the experimental period. Two blood samples each of 5 ml were collected from each of 50 Barki ewes (30 in Matrouh and 20 in Alexandria) ageing 3-4 years and 25 adult Rahmani ewes ageing 3-4 years in Alexandria. Data were collected, from the two geographical regions, The Sustainable Development Center for Matrouh Resources-Desert Research Center, Matrouh (31° 21’ 11” N, 27° 11’ 05” E) and Animal Production Research Station-Faculty of Agriculture-Alexandria University–Alexandria (31° 12’ 43” N, 29° 59’ 02” E).The blood samples were collected for biological and molecular tests, and then blood plasma was analyzed to determine the Total protein, Albumin, Globulin and Glucose calorimetrically by Hitachi 901 spectrophotometer and using STANBIO commercial kits. Blood plasma cortisol, triiodothyronine (T3) and thyroxin (T4) concentrations were determined by ELISA method using commercial kits (cortisol, T3 and T4 ELISA monobind Inc., lake Forest, CA, USA).At the day of blood sampling, the thermo-physiological parameters of RT◦C, ST◦C, WT◦C, RR (breaths/min) and PR (beats / min) were collected from individual ewes early in the morning (7:00 - 8:00 am) before access to feed and in the afternoon (2:00 - 3:00 pm). Also, THI was calculated from AT and RH in the two geographical regions during summer and winter seasons.Total RNA was extracted from the blood tissue, using total RNA Extraction kit (Total RNA Purification Mini Spin Kit), Real time-PCR was performed to amplify target and reference genes.It was carried out using the SYBR green following manufacturer instructions. The primers were esigned using primer 3 software from NCBI database.The results showed that:
A- The IL 2, IL 6, IL 12 and HSP 70 expression genes in Barki and Rahmani sheep obtained in summer and winter seasons indicated that:1- For Rahmani sheep, the expression of HSP 70 was upregulated in winter indicating that the gene is more related to cold tolerance. Differently, IL 2 and IL 6 genes expressions increased in 70 summer compared to winter, while that of IL 12 was not affected by THI values indicating that IL 2 and IL 6 but not IL 12 genes could be used as markers for thermal adaptability of Rahmani
sheep.
2- For Barki sheep, seasonal effects on expressions of IL-2, IL-6 and HSP 70 but not of IL-12 genes were significant (P < 0.05) in Alexandria area, showing upregulation in summer compared to winter. While the upregulation of HSP 70 gene expression was detected in Alexandria in winter rather than in summer, in Matrouh area, however, none of the tolerance genes showed significant changes in expression by season but were arbitrarily upregulated in either season.B- Blood biochemical constituents and hormones concentrations of Barki and Rahmani sheep in Alexandria and Matrouh:
1- For Rahmani, Seasonal effects on TP, albumin, T3, T4 and cortisol concentrations were not significant, while globulin and glucose concentrations were affected (P < 0.05) significantly during summer, probably to overcome the adverse effect of heat.
2- In Barki sheep, seasonal effects on blood plasma metabolites and hormonal concentrations were insignificant in both experimental locations.
C- Physio-tolerance traits of Barki and Rahmani sheep in Alexandria and Matrouh:1- For Rahmani, seasonal effects on ST, WT and RR were increased significantly (P < 0.01) in summer compared to winter but not RT and PR.
2- For Barki sheep, seasonal variations had no effect on RT in Alexandria (P = 0.30) and Matrouh (P = 0.27) areas. RT of ewes in experimental flocks were consistent at about 39°C with a range of differences not exceeding to 0.1°C between seasons and between locations. However, ST, WT, PR and RR but not RT and PR were different (P = 0.0001) in Alexandria, (P = .03) between seasons. These thermo-physiological parameters were higher in summer heat stressed sheep compared to those under winter thermoneutral conditions.