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Arkansas Animal Science Department Report 2001
was measured using [ 3 H]thymidine. Triplicate cultures from
each calf with each mitogen were supplemented with 25 ml
of fetal bovine serum.
Weights, ADG, and lymphocyte blastogenesis data
were analyzed using the GLM procedure of SAS (SAS Inst.
Inc., Cary, NC). The model included block, base supplement,
fish oil and the base supplement by fish oil interaction.
Literature Cited
Hankenson, K. D., et al. 2000. Proc. Soc. Exp. Biol. Med.
223:88
Kris-Etherton, P. M., et al. 2000. Am. J. Clin. Nutr.
71(Suppl.):179S
Theis, F., et al. 1999. J. Anim. Sci. 77:137-147.
Results and Discussion
Fish oil supplementation had a negative impact on ADG
(Table 2) when added to the corn-based supplement and no
effect when added to the wheat midd-based supplement
(base-supplement x fish oil interaction, P < 0.03). This negative
association could have been due to a decreased overall
fiber digestibility due to the added starch and oil.
Isolated lymphocytes (Table 3) from steers fed the
corn-based supplement with fish oil had a greater response to
stimulation with CONA than lymphocytes from calves fed
the corn-based supplement, and there was no effect of fish oil
addition to the wheat midd-based supplement (base-supplement
x fish oil interaction, P < 0.01). Isolated lymphocytes
from steers fed the corn based supplement had a greater
response to stimulation with PHA (P < 0.05) and PWM (P <
0.01) than lymphocytes from steers fed the wheat midds
based supplements (base-supplement effect, P < 0.05). Fish
oil supplementation increased the blastogenic response of
lymphocytes to PHA (P = 0.09) and PWM (P = 0.04) over the
basal supplemented steers. The stimulation in the immune
system was unexpected since in previous studies in humans
and rats it has been shown that fish oil supplementation modulates
and/or decreases the activity of the immune system
(Hankenson et al., 2000). Two more trials are currently being
conducted to further elucidate the effects of fish oil supplementation
on the immune system of cattle as well as to determine
the fatty acid composition of the meat.
Implications
This study suggests that supplementing fish oil to grazing
cattle may boost their immune response and therefore aid
in the reduction of morbid cattle. However, the depression in
growth may eliminate any additive effects of stimulating the
immune system. The determination of the effects of supplementing
fish oil to grazing cattle on carcass characteristics
has yet to be determined.
Acknowledgements
The authors would like to extend their deepest gratitude
to J. A. Hornsby, G. Carte, and J. Sligar for the management
and care of the experimental animals. The authors would also
like to acknowledge Omega Protein for donating the fish oil.
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