Effects of intravenous triacylglycerol emulsions on lymphocyte responses to mitogens in fasted dairy cows undergoing intense lipomobilization
Author(s)
Lacetera, Nicola
Scalia, Daniela
Mashek, Dough G.
Bernabucci, Umberto
Grummer, Ric R.
Date Issued
2007
Type
Article
Abstract
The objective of the study was to assess the effects of intravenous infusion of triacylglycerol
(TAG) emulsions derived from different lipid sources on responses to mitogens of peripheral
blood mononuclear cells (PBMC) isolated from fasted dairy cows. Six multiparous, nonpregnant,
non-lactating Holstein cows were used in a replicated 3r3 Latin Square design. For
4 d, cows were fasted and infused intravenously with a 20% TAG emulsions derived from
tallow (TA), linseed oil (LO) or fish oil (FO). Fasting was employed to induce energy deficit
and lipid mobilization. Emulsions were administered for 20 to 30 min every 4 h throughout the
4 d fast at a rate of 0.54 g TAG/kg BW/d. Blood samples were taken before the first infusion,
and then every 24 h during the fast. Blood was utilized to assess DNA synthesis, IgM and
interferon-gamma (IFN-c) secretion by PBMC stimulated with mitogens. In TA infused cows
there was a decline of PBMC ability to respond to mitogens, which was significant 48 h after
initiation of the infusion period for DNA synthesis and IFN-c secretion. In LO or FO infused
cows, PBMC responses to mitogens were not altered during the infusion period, and in some
cases PBMC responses to mitogen was improved at 72 and 96 h after initiation of treatments.
Effects of TAG infusion on PBMC responses to mitogens depended on the lipid source
suggesting that LO or FO can attenuate the negative effects of fasting on immune functions.
Citation
THE JOURNAL OF DAIRY RESEARCH, vol. 74; p. 323-328
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