8 research outputs found
Effects of stage of lactation and time of year on plasmin-derived proteolytic activity in bovine milk in New Zealand
The objective of this study was to determine the effects of stage of lactation (SOL) and time of year on plasmin-derived proteolytic activity in the milk of pasture-fed dairy cows in New Zealand. Four herds of 20 Friesian cows were used, one herd calving in each of January, April, July and October. Cows grazed ryegrass/white clover pasture only, except during June (winter) when all cows received supplementary pasture silage. Milk samples were collected on four occasions during the year (spring, summer, autumn and winter) from each cow in milk, to give a total of three samples per cow (early, mid and late lactation; c. 30, 120 and 220 days after calving, respectively). Milk samples were analysed for plasmin-derived proteolytic activity. There was no effect of either SOL or time of year on plasmin activity and therefore yields of plasmin followed patterns in milk yield (highest in early lactation and in summer). There were effects of both SOL and time of year on plasminogen-derived and total plasmin plus plasminogen-derived activity, both of which were highest in late lactation and in spring. Changes in plasminogen-derived activity and total plasmin plus plasminogen-derived activity due to SOL were not only due to the decrease in milk yield associated with advancing lactation, because enzyme yields were also increased with advancing lactation. Similarly, effects of time of year on plasminogen-derived activity and total plasmin plus plasminogen-derived activity could not be attributed solely to concomitant changes in milk yield, and may be influenced by the variation in the quality and quantity of feed during the year inherent in a pasture-based dairy system. Effects of SOL on proteolytic activity were greater than, and independent of, effects of time of year
Effect of unilateral once or twice daily milking of cows on milk yield and udder characteristics in early and late lactation
Reduction in heat-induced gastrointestinal hyperpermeability in rats by bovine colostrum and goat milk powders
Effects of stage of lactation and time of year on plasmin-derived proteolytic activity in bovine milk in New Zealand
Partitioning of milk accumulation between cisternal and alveolar compartments of the bovine udder: relationship to production loss during once daily milking
Impact of dietary dairy polar lipids on lipid metabolism of mice fed a high-fat diet
The effect of milk polar lipids on lipid metabolism of liver, adipose tissue, and brain and on composition of intestinal microbiota was investigated. C57BL/6J mice were fed a high-fat diet (HFD) for 5 weeks, followed by 5 weeks with HFD without (control) or supplemented with total polar lipids (TPL), phospholipids (PL), or sphingolipids (SPL). Animals fed SPL showed a tendency for lower triglyceride synthesis (P = 0.058) in the liver, but not in adipose tissue. PL and TPL reduced de novo hepatic fatty acid biosynthesis. The ratio of palmitoleic to palmitic acid in the liver was lower for animals fed SPL or TPL compared to control. There was little effect of the supplementation on the cecal microbiota composition. In the brain, DHA (C22:6) content correlated negatively with tetracosanoic acid (C24:0) after TPL supplementation (-0.71, P = 0.02) but not in control (0.26, P = 0.44). Arachidonic acid (C20:4) was negatively correlated with C24:0 in both groups (TPL, -0.77, P = 0.008; control, -0.81, P = 0.003)
Impact of Dietary Dairy Polar Lipids on Lipid Metabolism of Mice Fed a High-Fat Diet
The
effect of milk polar lipids on lipid metabolism of liver, adipose
tissue, and brain and on composition of intestinal microbiota was
investigated. C57BL/6J mice were fed a high-fat diet (HFD) for 5 weeks,
followed by 5 weeks with HFD without (control) or supplemented with
total polar lipids (TPL), phospholipids (PL), or sphingolipids (SPL).
Animals fed SPL showed a tendency for lower triglyceride synthesis
(<i>P</i> = 0.058) in the liver, but not in adipose tissue.
PL and TPL reduced de novo hepatic fatty acid biosynthesis. The ratio
of palmitoleic to palmitic acid in the liver was lower for animals
fed SPL or TPL compared to control. There was little effect of the
supplementation on the cecal microbiota composition. In the brain,
DHA (C22:6) content correlated negatively with tetracosanoic acid
(C24:0) after TPL supplementation (−0.71, <i>P</i> = 0.02) but not in control (0.26, <i>P</i> = 0.44). Arachidonic
acid (C20:4) was negatively correlated with C24:0 in both groups (TPL,
−0.77, <i>P</i> = 0.008; control, −0.81, <i>P</i> = 0.003)