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Effect of early heat exposure on some physiological and histological changes in the liver and kidney of rabbits before weaning
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Abstract: Forty five New Zealand White (NZW) rabbits were distributed into two groups as follows: The first group was kept under normal ambient temperature (25±3°C) as a control group. The second group (acclimated group) was exposed to high ambient temperature (36±3°C) at day 3post-partum for 1h for 3 consecutive days by using electric heaters. At 21 days of age each group was divided into two treatments so that, the first group includes the first and second treatments while, the second group includes the third and fourth treatments as follows: The first treatment (C) was animals kept as control without exposure to heat stress. The second treatment (HS) was subjected to high temperature (38°C +0.5) and 75-80% humidity for 4 hrs (12.00-04.00 pm) daily for the period of one week till 28 days of age (the end of the experimental period). The third treatment (TA1) was kept without exposure to heat stress.
The fourth treatment (TA2) was subjected to high temperature (38°e +0.5) and 75-80% humidity for 4 hrs (12.00-04.00 pm) daily for the period of one week till 28 days of age (the end of the experimental period). Cortisol, urea, creatinine, activity of aspartate (AST) and alanine (ALT) aminotransferases, the malondialdehyde (MDA) level and superoxide dismutase and catalase (CAT) activities were measured in the tissues of liver and kidney of the rabbits. The liver and kidney were collected and examined under a light microscope with hematoxylin-eosin staining. The results obtained showed that the most important results: it found that MDA levels significantly higher in liver and kidney of the heat stressed group, followed by thermal acclimatization group exposed to heat stress than thermal acclimatization group without exposed to heat stress followed by the control group.
- The antioxidant enzymes activities in the tissues of the kidneys and the liver were significantly higher for thermal acclimated group (TA1), followed by group (TA2) and the control group than heat stressed group (HS).
- Heat stress led to a marked increase in the enzymes AST, ALT, as well as in renal function measurements compared with the control group, while thermal acclimatization led to a marked improvement in the previous measurements.
Moreover, histological studies of the heat stressed group revealed dilatation of the hepatic sinusoids, interstitial hemorrhage and dilatation of the renal tubules. Notably, early thermal acclimatization completely reversed the histological changes that were induced by heat stress yielding levels that were similar to the control group. The results revealed that
the early thermal acclimatization has remarkable potentials to counteract heat stress caused alterations of cortisol as well as oxidative stress biomarkers probably through their anti-stress and free radical defusing effects It could be concluded that early thermal acclimation very effective in reducing stress-induced organ damage by inhibiting lipid peroxidation and supporting the cellular antioxidant defense system.
Key Words: Rabbits, Heat Stress, Antioxidant Enzymes, Histological, Liver and Kidney.
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| Publication year |
2015
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| Pages |
149-175
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| Availability location |
معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- دقى- جيزة
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| Availability number |
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| Organization Name |
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| Country |
Egypt
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| serial title |
Egyptian Poultry Science
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| ISSN |
1110-5623
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| Volume |
35
. 1
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| Author(s) from ARC |
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| Agris Categories |
Animal physiology - Growth and development
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AGROVOC
TERMS |
Antioxidants.
Enzymes.
Heat stress.
Kidneys.
Liver.
Rabbits.
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| Proposed Agrovoc |
Histological;
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| Publication Type |
Journal
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