Antioxidant defence of colostrum and milk in consecutive lactations in sows

<p>Abstract</p> <p>Background</p> <p>Parturition is supposed to be related to oxidative stress, not only for the mother, but also for the newborn. Moreover, it is not clear whether consecutive pregnancies, parturitions, and lactations are similar to each other in regards to intensity of metabolic processes or differ from each other. The aim of the study was to compare dynamic changes of antioxidative parameters in colostrum and milk of sows taken during 72 h postpartum from animals in consecutive lactations. Activities of glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), and superoxide dismutase (SOD), and amount of vitamin A and C were measured. Healthy pregnant animals were divided into 4 groups according to the assessed lactation: A -1^stlactation (n = 10), B - 2^ndand 3^rdlactation (n = 7), C - 4^thand 5^thlactation (n = 11), D - 6^th- 8^thlactation (n = 8). The colostrum was sampled immediately after parturition and after 6, 12, 18 and 36 h while the milk was assessed at 72 h after parturition. Spectrophotometric methods were used for measurements.</p> <p>Results</p> <p>The activity of antioxidative enzymes and the concentration of vitamin A increased with time postpartum. The concentration of vitamin C was the highest between the 18th and 36th h postpartum.</p> <p>Conclusions</p> <p>Dynamic changes in the values of antioxidant parameters measured during the study showed that sows milk provides the highest concentration of antioxidants in the 2^ndand 3^rdand 4^thand 5^thlactation giving the best defence against reactive oxygen species to newborns and mammary glands.</p

Reduction of ultraviolet light-induced DNA damage in human colon cancer cells treated with a lactoferrin-derived peptide

Treatment of Caco-2 cells with the peptide lactoferricin(4-14), results in reduction of the growth rate by prolongation of the S phase of the cell cycle. Lactoferricin(1-25) is formed in the gut by cleavage from lactoferrin and the bioactive amino acids are found within lactoferricin(4-14). Our hypothesis is that the reduction of the rate of S phase progression may result in increased DNA repair. To test this hypothesis, Caco-2 cells were subjected to UV light that caused DNA lesions and then the cells were grown in the absence or presence of 2.0 mu M lactoferricin(4-14). Evaluation of DNA strand breaks using the comet assay showed that lactoferricin(4-14) treatment indeed resulted in a reduction of comets showing damaged DNA. In the search for a mechanism, we have investigated the levels of several proteins involved in cell cycle regulation, DNA replication, and apoptosis using Western blot. Lactoferricin(4-14) treatment resulted in an increased expression of flap endonuclease-1 pointing to increased DNA synthesis activity. Lactoferricin(4-14) treatment decreased the expression of the proapoptotic protein B-cell lymphoma 2-associated X protein (or Bax), indicating decreased cell death. As we have found previously, lactoferricin(4-14) treatment reduced the expression of cyclin E involved in the G(1)/S transition. Immunofluorescence microscopy showed that a lower gamma-H2AX expression in lactoferricin(4-14)-treated cells, pointing to more efficient DNA repair. Thus, altogether our data show that lactoferricin(4-14) treatment has beneficial effects

Relationship between somatic cell count, individual leukocyte populations and milk components in bovine udder quarter milk

The somatic cell count (SCC) in bovine milk is an indicator of udder health and milk quality. Individual cell populations, i.e., macrophages, lymphocytes and polymorphonuclear neutrophils, were identified and their relationship to milk components such as acute-phase proteins (serum amyloid A (SAA) and alpha(1)-acid glycoprotein), lactic acid and lactoferrin (LF), as well as protein, fat and lactose, were studied in foremilk from separate udder quarters. The whey proteins and peptides were studied using two-dimensional gel electrophoresis, which was shown in the present study to be a useful method of assessing udder health and milk quality. The growth of a starter culture was evaluated using a conductance method as a simulation of fermentation processes relevant for cheese production. The investigation showed that LF, SAA, L-lactate and lactose are reliable indicators of milk quality on udder quarter level. The correlations between SCC, or the individual cell populations, and the potential indicators were highly significant. (c) 2005 Elsevier Ltd. All rights reserved

Effect of shortening or omitting the dry period of Holstein-Friesian cows on casein composition of milk

The aim of this study was to evaluate the effect of shortening or omitting the dry period of dairy cows on milk casein composition. For this study, we analyzed milk samples of 90 cows with a dry period of 0, 30, or 60 d and either a glucogenic or a lipogenic ration in early lactation. Milk was sampled at 6 and 2 wk prepartum and at 2, 6, and 12 wk postpartum. Milk was analyzed for casein (CN) composition by capillary zone electrophoresis, and isoforms of κ-CN were measured by reversed phase-HPLC. Shortening the dry period from 60 to 30 d reduced the αS1-CN fraction by 3.8% and increased the αS2-CN fraction by 5.5%. In milk from cows with a 0-d dry period, the glycosylated κ-CN fraction in late lactation increased from 8 to 12% between 6 and 2 wk prepartum. After calving, the glycosylated κ-CN fraction in milk was higher for cows with a 0-d dry period (6.7%) compared with cows with a 60-d dry period (5.2%). The glycosylated κ-CN fraction at 2 wk postpartum was negatively correlated with milk yield, suggesting that glycosylation was related to reduced productivity of mammary epithelial cells. In early lactation, the β-CN fraction was reduced in milk of cows with a 0-d dry period. A lowered β-CN fraction was associated with high somatic cell count and greater parity, indicating that it was the result of proteolytic activity. In conclusion, casein composition changes that result from shortening the dry period from 60 to 30 d are not expected to affect processing characteristics of milk. Applying a 0-d dry period may affect processability of milk because of a higher glycosylated κ-CN fraction, and possibly because of higher proteolytic activity compared with a 60-d dry period