Distribution patterns of the glucose transporters GLUT4 and GLUT1 in skeletal muscles of rats (Rattus norvegicus), pigs (Sus scrofa), cows (Bos taurus), adult goats, goat kids (Capra hircus), and camels (Camelus dromedarius).

Earlier studies demonstrated that forestomach herbivores are less insulin sensitive than monogastric omnivores. The present study was carried out to determine if different distribution patterns of the glucose transporters GLUT1 and GLUT4 may contribute to these different insulin sensitivities. Western blotting was used to measure GLUT1 and GLUT4 protein contents in oxidative (masseter, diaphragm) and glycolytic (longissimus lumborum, semitendinosus) skeletal muscle membranes of monogastric omnivores (rats and pigs), and of forestomach herbivores (cows, adult goats, goat kids, and camels). Muscles were characterized biochemically. Comparing red and white muscles, the isocitrate dehydrogenase (ICDH) activity was 1.5-15-times higher in oxidative muscles of all species, whereas lactate dehydrogenase (LDH) activity was 1.4-4.4-times higher in glycolytic muscles except in adult goats. GLUT4 levels were 1.5-6.3-times higher in oxidative muscles. GLUT1 levels were 2.2-8.3-times higher in glycolytic muscles in forestomach herbivores but not in monogastric animals. We conclude that GLUT1 may be the predominant glucose transporter in glycolytic muscles of ruminating animals. The GLUT1 distribution patterns were identical in adult and pre-ruminant goats, indicating that GLUT1 expression among these muscles is determined genetically. The high blood glucose levels of camels cited in literature may be due to an "NIDDM-like" impaired GLUT4 activity in skeletal muscle.

Assessment of the antioxidative potential of dietary supplementation with α-tocopherol in low-nitrite salami-type sausages.

The objective of this study was to determine the effects of dietary α-tocopherol supplementation to pigs on the lipid stability of nitrite-reduced salami-type sausages (custom-produced for this study). Fourteen crossbred pigs were divided into two equal groups. The control group (CG) was fed a basal diet containing 34ppm α-tocopherol, and the experimental group (EG), a diet supplemented with 364ppm α-tocopherol, both for 35 days. After slaughter, salami-type sausages were produced with the addition of different nitrite levels in the curing salt (100, 50, 25 and 0ppm), ripened for four weeks, sliced, and packaged under a protective atmosphere (80 parts N(2) to 20 parts CO(2)). The packed products were stored for eight weeks under simulation of the usual conditions in self-service shelves with permanent lighting (9°C, 200 lux). The sausages were regularly assessed for their oxidative status (thiobarbituric acid-reactive substances, fatty acid pattern) and the amount of α-tocopherol, and by sensory evaluation. In the EG sausages, α-tocopherol concentrations were twice as high and TBARS were lower than in the CG sausages. The α-tocopherol in EG prevented the loss of unsaturated fatty acids during storage. Sausages of EG containing 100ppm nitrite had the longest sensory stability. However, the biochemical parameters did not indicate that nitrite had any effect on the antioxidative potential of the sausages.