The dynamics of individual whey protein concentrations in cows' mammary secretions during the colostral and early lactation periods.

The bovine whey consists of more than 200 different types of proteins, of which ß-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulins and lactoferrin predominate. However, their concentrations are not stable due to the existence of protein dynamics during a transition from colostrum secretion to mature milk. To evaluate the dynamics of whey proteins of Jersey cows during a colostral phase and first month of lactation and an influence of the number of lactations, 268 milk samples from 135 Jersey cows were selected through a clinical evaluation. Whey was obtained by rennet coagulation of the mammary secretion. The concentration of total proteins was determined by the biuret method and their fractions were identified by 12% dodecyl sulfate-polyacrylamide gel electrophoresis (12% SDS-PAGE). Maximum concentrations of all protein fractions were observed in the first 12 h of lactation, reducing over the course of the study. Modification of the protein predominance was also observed. The transition from colostrum secretion to milk occurred between 24 and 72 h postpartum. There was an influence of the number of lactations on the dynamics of whey proteins, indicating that multiparous cows had better immunological and nutritional quality when compared to primiparous cows.

Chemopreventive effects of pequi oil (Caryocar brasiliense Camb.) on preneoplastic lesions in a mouse model of hepatocarcinogenesis.

Pequi (Caryocar brasiliense Camb.), a fruit from Brazil's central region, was evaluated for its chemopreventive effects on preneoplastic liver lesions induced by the carcinogen diethylnitrosamine (DEN) in mice. BALB/c mice, 14 days of age, received an intraperitoneal injection at 10 µg/g of DEN. The mice received either of two doses of pequi oil (100 or 400 mg/kg) daily from the age of 30 days and were killed at the age of 189 days. Stereological parameters, including the volume density (Vv) and the total volume (Vtot) of the lesions (preneoplastic and adenomas), were measured and the expression of cytokeratins CK8/18 was evaluated. The total volume of lesions and adenomas was reduced by 51% in the group treated with the carcinogen and 400 mg/kg of pequi oil administered daily by an oral gavage for 25 consecutive weeks. In addition, some mice in this group did not develop lesions. Among the remaining preneoplastic lesions in this group, the number of remodelled profiles increased by 2.4-fold in the 400-mg pequi oil-treated mice relative to the 100-mg-treated mice. Our results show that pequi oil exerts a hepatoprotective effect against DEN-induced development of preneoplastic lesions and adenoma in mice and the potential for its use in the prevention of liver cancer.