Stress is experienced during cancer, and impairs the immune system’s ability to protect the body. Our aim was to investigate if isolation stress has an impact on the development of tumors in rats, and to measure the size and number of tumors and the levels of corticosterone. Breast cancer was induced in two groups of female rats (N=20) by administration of a single dose of N-methyl-N-nitrosourea 50 mg/kg. Rats in the control group (cancer induction condition) were allowed to remain together in a large cage, whereas in the second group, rats were also exposed to a stressful condition, that is, isolation (cancer induction and isolation condition, CIIC). The CIIC group displayed anxious behavior after 10 weeks of isolation. In the CIIC group, 16 tumors developed, compared with only eleven tumors in the control cancer induction condition group. In addition, compared with the control group, the volume of tumors in the CIIC group was greater, and more rats had more than one tumor and cells showed greater morphological damage. Levels of corticosterone were also significantly different between the two groups. This study supports the hypothesis that stress can influence the development of cancer, but that stress itself is not a sufficient factor for the development of cancer in rats. The study also provides new information for development of experimental studies and controlled environments.

Background: Choline is a nutrient with numerous metabolic functions, but its requirements for ruminants are unknown. The supplementation with bypass choline could enhance productivity. Methods: Twenty-four male lambs (Rambouillet 23.5 kg±3.17 kg initial BW) were fed a basal diet with treatments which consisted of a control and oral doses of ruminally-protected choline (4 g/d RPC) and plant-based choline (4 g/d Biocholine) in a completely randomized design with initial weight as a covariate. The experiment was conducted for 42 days during which live weight, dry matter intake, carcass characteristics, blood metabolites and basic hemograms were measured. Result: The daily gain in lambs was similar between treatments. Intake was higher in lambs given Biocholine (1.32 kg/d). The L* (represents the light to dark color) value and mineral content in the meat were improved with both sources of choline. Blood triglycerides increased by RPC compared with the other treatments and cholesterol was reduced by Biocholine. Alanine transaminase (ALT) and aspartate aminotransferase (AST) activity decreased by effect of choline. Hematological parameters were affected by choline supplementation regardless of the source; erythrocyte, monocytes and lymphocytes count decreased with both sources of choline in growing lambs.

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