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Tanta University (2018)

Physiological and Immunological Responses to Heat Stress in Baladi and Shami Goat

El-Shehry, Shaimaa Talat

Titre : Physiological and Immunological Responses to Heat Stress in Baladi and Shami Goat

Auteur : El-Shehry, Shaimaa Talat.

Etablissement de soutenance : Tanta University

Grade : Doctor of Philosophy (PhD) in Science (Zoology) 2018

Résumé
Egyptian desert is considered as a semi-arid region with high ambient temperature in summer. Recently, several studies showed that heat stress has a great effect on animals. The aim of current study is to evaluate the effect of heat stress on some physiological, immunological parameters and HSP70 level of two different types of goats, local Baladi and Shami breeds during five different time points (P1, P2 P3, P4 and P5) in summer, 2016 ; P1 in July, P2 in August, P3 and P4 in September and P5 in October. In this study two groups of Baladi and Shami goats were used. Baladi and Shami goats were divided into unexposed and exposed subgroups to solar radiation (n in each group =10). The results showed decrease in body weight in both breeds by the end of periods (P5). On the other hand, the results showed increase in thermoregulatory responses (RR, CT, ST, ET and RT) in P1, P2 and P3 and decreased at P4 and P5. WBCs in both breeds decreased by the end of experiment. Absolute number of lymphocytes in exposed and unexposed Baladi goats showed decrease by the end of experiment, but Shami goats showed increase at P5. Exposed and unexposed Baladi and Shami goats showed decrease in relative number of lymphocytes, monocytes and granulocytes. Exposed Baladi and Shami goats compared with unexposed Baladi and Shami groups showed an increase at P5 in RBCs, HCT, MCV MCH and MCHC. Exposed and unexposed Baladi and Shami goats showed increase at P5 in ALT , total lipids, albumin, ALP activity and glucose. However, both breeds exposed and unexposed showed decrease at P5 in cholesterol and total protein. Both breeds especially exposed goats showed decrease under thermal stress conditions in thyroid hormones including T3 and T4. Our results showed increase in IL-6 and IL-1β levels in exposed and unexposed Shami and Baladi goats by the end of experiment compared with the beginning. HSP70 was increased in Shami exposed group than Baladi exposed group under the same condition. Exposed and unexposed Baladi and Shami goats showed decrease in Na and Cl levels at P5, however, they showed increase in K and P. Based on these results, Baladi goats can tolerate the impact of heat stress more than Shami one.

Présentation étendue (EULC)

Page publiée le 26 février 2019