Effect of citrus pulp silage feeding on concentration of beta-cryptoxanthin in plasma and milk of dairy cows

Citrus pulp is known to contain a functional molecule of beta-cryptoxanthin which is one of the carotenoids showing anti-oxidative capacity. Influences of citrus pulp silage feeding to dairy cows on beta-cryptoxanthin concentration in plasma, other blood properties and milking performances were investigated. Four Holstein cows were fed total mixed ration (TMR) containing citrus pulp silage 20% dry matter (DM) for 2 weeks with free access to the TMR. Dry mater intake, milk production and milk components 2 weeks later were not altered compared with those of the control group without citrus pulp silage. Activities of aspartate aminotransferase, alanin aminotransferase and gamma-glutamyltranspeptidase in plasma were not affected by feeding of citrus pulp silage. Concentrations of protein, albumin, sulfhydryl residue, ascorbic acid, thio-barbituric acid reactive substance and urea nitrogen in plasma were also not altered by citrus pulp silage feeding. Concentration of beta-cryptoxanthin in plasma was increased approximately 20-fold compared with the control group (P < 0.05). Content of beta-cryptxanthin in pooled milk fat fraction was also increased approximately three times compared with that of the control group. Feeding of TMR containing citrus pulp silage 15% DM for 30 days to eight dairy cows also increased plasma beta-cryptoxanthin concentration 30-fold compared with that before feeding.