The effects of supplemental chromium (Cr) in the diet, or by direct ad
dition to the culture medium on proliferation of bovine peripheral blo
od lymphocytes (PBL) was evaluated with and without addition of the mi
togen concanavalin A (con A). Twenty-four stressed steer calves were r
andomized (three animals per pen) to the following treatments: control
diet (high quality corn silage) and control diet supplemented with 0.
14 ppm chelated Cr. The PBL blastogenic activity was accessed using 0,
2 and 10 ug/ml con A on d 0, 7, 14, 21, 28, 35, and 49 following arri
val of calves from sales barns. Blastogenic activity was measured by u
ptake of methyl-H-3-thymidine. The PBL from calves fed dietary Cr show
ed increased (P < 0.05) blastogenic activity following incubation with
culture medium containing the higher concentration (10 ug/ml con A) o
f mitogen. An interaction between Cr and health status of calves occur
red with or without mitogen (P < 0.05). Morbid animals had lower PBL b
lastogenic responses but supplemental Cr increased (P < 0.05) this res
ponse of morbid animals. However, supplemental Cr had no effect on res
ponse of healthy animals. When soluble chelated Cr was directly added
to the culture medium at 0, .045, .45 and 4.5 ppm, Cr enhanced (P < 0.
05) blastogenic activity at both concentrations of mitogen, as well as
without mitogen stimulation. In addition, using PBL from eight animal
s fed the control diet from d 0 to 120, chelated Cr and CrCl3, were di
rectly added in the PBL culture medium at 0, 0.0045, 0.045, 0.45 and 4
.5 ppm, and the same enhanced blastogenic activity was observed. Howev
er, chelated Cr showed greater (P < 0.10) enhancement of PBL activity
at 0.045 to 0.45 ppm and CrCl3 at 0.0045 ppm concentration (P < 0.05).
These results confirmed previous indications that Cr can effect certa
in aspects of cell mediated immunity, which may contribute to the morb
idity reduction of calves fed supplemental Cr.