The aim of the present study was to investigate the effects of oral administration of the insulin-like growth factor-I-rich fraction (IGF-I-RF) from bovine colostral whey on the regulation of blood glucose levels in streptozotocin (STZ)-induced diabetic mice. We obtained a peptide fraction containing IGF-I (10 ng/mg protein) from Holstein colostrum within 24 h after parturition by using ultrafiltration. The blood glucose levels of STZ-induced diabetic mice fed with IGF-I-RF (50 μg/kg per d) were significantly reduced by 11 and 33 % at weeks 2 and 4, respectively (P < 0·05). The body weights of STZ-induced diabetic mice increased following the oral administration of the IGF-I-RF. The kidney weights of STZ-induced diabetic mice decreased significantly (P < 0·05) following the administration of the IGF-I-RF, and the liver weights of STZ-induced diabetic mice decreased significantly (P < 0·05) following the administration of 50 μg/kg per d of the IGF-I-RF. The present results indicate that the IGF-I-RF obtained from Holstein colostrum could be a useful component for an alternative therapeutic modality for the treatment of diabetes in insulin-resistant patients.

We evaluated the effect of a commercial bovine colostral whey on the complement-mediated immune responses of calves. Two groups of neonatal calves were fed, in addition to whole milk (WM) and pooled colostrum (PC), different amounts of a commercial immunoglobulin concentrate made from pooled colostral whey (Ig-C) for the first two feedings post natum. The control group was fed WM and PC only. Serum samples were obtained at the ages of 2, 7, 14 and 30 d. Bacteriolytic activity against complement-sensitive Escherichia coli JM103 and opsonic activity against complement-lysis-resistant E. coli IH3080 strains were studied, as well as the levels of C3 complement component and E. coli JM103 specific antibodies in the sera.

Groups fed Ig-C had 2–3 times higher bacteriolytic activity than the control group of both the classic (P < 0·005) and alternative pathways (P < 0·0001) at days 2 and 7 post natum. This effect is obviously not caused solely by the antibodies ingested but also involves other unknown colostral factors, possibly lectins. The opsonisation capacities of the sera correlated well with the amounts of immunoglobulins ingested (P < 0·05) at days 2–14. The levels of C3 component in sera did not differ between the groups. In the group fed the largest amount of immunoglobulins levels of E. coli JM103-specific antibodies were highest (P < 0·0001). It can thus be concluded that the antibody independent complement activities of serum can be increased substantially by feeding colostral whey concentrate to calves during their first days of life.