The effect of docosahexaenoic acid–rich algae oil supplementation in milk replacer on blood concentration of docosahexaenoic acid metabolites and cytokine production in white blood cells in calves

This study aimed to investigate the effect of dietary supplementation with docosahexaenoic acid-rich algae oil (DHA-RAO) on blood levels of selected docosahexaenoic acid (DHA) metabolites, and to assess its potential influence on cytokine production by white blood cells in neonatal dairy calves. Twenty clinically healthy Holstein male calves (8.1 ± 2 d old and 46.6 ± 4.2 kg, mean ± SD) were allocated into 2 experimental groups of 10 animals each: (1) not supplemented with DHA-RAO in milk replacer (MR; group CON); and (2) supplemented with 7.5 g of DHA-RAO/d in MR (group SUP). Calves were fed 6 L of MR/d with or without supplementation for 4 wk. The estimated DHA intake in the SUP group was 2.53 g/d. The MR intake and fecal score were recorded daily, and BW was recorded weekly. Blood samples were collected for complete blood count, measurement of DHA metabolite levels (D-series resolvins 1-4 and neuroprotectin D1), and whole blood immunostimulation assay. White blood cells were isolated from blood after ex vivo mitogen stimulation and analyzed for mRNA expression of pro- and anti-inflammatory cytokines. Supplementation of DHA-RAO in MR resulted in reduced ADG and lower final BW, accompanied by a tendency toward an increased blood DHA concentration. Neither the blood levels of resolvins 1-4 and neuroprotectin D1 nor the ex vivo cytokine response of mitogen-stimulated white blood cells collected at the end of the study were affected by the treatment. In conclusion, these findings suggest that although DHA-RAO may influence growth performance, its short-term supplementation does not appear to modulate systemic inflammation parameters or blood DHA metabolite levels in neonatal calves. To our knowledge, this is the first study to investigate DHA-derived specialized pro-resolving mediators in this species.