The metabolism and morphology of brown adipose tissue from newborn calves /
The effect of prepartum protein restriction on lipid metabolism and morphology of perirenal brown adipose tissue (BAT) from newbom calves was examined. Angus heifers bred to a single Wagyu sire were assigned randomly to one of two isocaloric diets containing 60 or 100% of the NRC requirements for p...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739363611&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The effect of prepartum protein restriction on lipid metabolism and morphology of perirenal brown adipose tissue (BAT) from newbom calves was examined. Angus heifers bred to a single Wagyu sire were assigned randomly to one of two isocaloric diets containing 60 or 100% of the NRC requirements for protein. Diets were fed for the last 150 d of gestation. Body condition scores and weight gain were severely impaired in heifers fed the protein restricted diet; however, birth weights and perirenal BAT weights of newborn calves were not affected. The incorporation of acetate or glucose into neutral lipids in BAT was not affected by diet and acetate was utilized as a substrate at a significantly greater rate than glucose. Fatty acid biosynthesis in white adipose (WAT) tissue was very low. However lipogenesis from glucose was significantly higher in WAT than in BAT. Cellularity measurements were not affected by diet. Because of the considerable variation in the concentration of uncoupling protein (UCP) MRNA within each diet treatment, the UCP MRNA levels in BAT did not differ with dietary treatment. Brown adipocytes were generally unilocular and the cytoplasmic spaces were filled with numerous elongated mitochondria containing packed cristae. Because Bos indicus calves experience greater neonatal mortality than Bos taurus calves if cold stressed, the effects of breedtype on metabolism and morphology of perirenal BAT from newbom Brahman and Angus calves were examined. Although Angus cows weighed significantly more at parturition, the Angus calves weighed significantly less at birth than Brahman calves. Perirenal BAT weights were not different between breedtype. Brahman BAT contained fewer adipocvtes per gram of tissue than Angus BAT. Fatty acid biosynthesis from glucose expressed on a per cell basis was higher in Brahman BAT than in Angus BAT. Lipogenesis from acetate was not different between breedtype. There also was no difference in UCP MRNA level between breedtypes. There were no remarkable differences in Brahman and Angus BAT morphology. The WAT from both breedtypes contained adipocytes with numerous differentiated mitochondria adjacent to typical white adipocytes suggesting an involution of BAT to WAT in that depot. |
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| Item Description: | Vita. "Major Subject: Nutrition". |
| Physical Description: | viii, 89 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 70-80. |