Effect of Level of Spirulina Supplementation on Oxidative Stress, Immunity, Productive Performance and Reproductive Parameters during the Transition Period By Grazing Dairy Cattle

Previous data suggested that grazing dairy cattle could have higher levels of oxidative stress compared to confined animals. There is available a spirulina product containing phycocianin which has been characterized as a potent antioxidant. Nevertheless, there is little data available on antioxidant supplementation on grazing dairy cattle during the transition period. Therefore, the objective of this experiment was to evaluate the effects of spirulina supplementation on oxidative stress, immunity and productive performance and reproductive parameters during the transition period by grazing dairy cattle. Twenty-four multiparous gestating cows (BW = 543 ± 57 kg) were enrolled in this experiment, and were stratified by expected calving date. Cows were aleatory assigned to 3 experimental groups; 1) Control; no supplementation of spirulina; 2) Spirulina-15 (15 g of spirulina; 2 g phycocianin); and 3) Spirulina-30 (30 g of spirulina; 4 g phycocianin). Treatments initiated 3 weeks before parturition and were mixed in an energy supplement fed daily in the morning at a rate of 3 kg/cow (DM). Body weight and body condition score were monitored at - 21, 1, 21 d, relative to calving. Blood samples were collected at the same time points (before feeding) to measure oxidative stress indicators. All cows calved within a period of 12 wk, and graze in the same paddock during the experimental phase. The day of parturition colostrum samples and blood samples from calves were collected to measure IgG concentrations. After parturition milk production, milk components and somatic cell count were monitored daily and weekly, respectively. Incidence of postpartum reproductive diseases were also recorded. Body weight, body weight loss, and body condition score were not altered by treatment (P > 0.46), nevertheless in average cows had 2.9 and 4% reduction on body weight relative to the beginning of the trial. Total antioxidative capacity was not affected by spirulina supplementation (P > 0.31) at any time point measured. There was a tendency for a quadratic increased on IgG concentration in colostrum as spirulina supplementation increased (P = 0.10). Nevertheless, there were no differences on calves serum IgG concentration attributed to treatment (P=0.98). Milk production, milk components, somatic cell count and reproductive postpartum diseases were not altered by treatment (P > 0.16). Results from this experiment suggests no positive or negative effects of spirulina supplementation on oxidative stress, productive performance and reproductive parameters during the transition period by grazing dairy cattle. However, IgG response by spirulina supplementation requires further exploration.