Effects of seasonal changes in feeding management under part-time grazing on the evolution of the composition and coagulation properties of raw milk from ewes.

Ewe raw milk composition, rennet coagulation parameters, and curd texture were monitored throughout the milk production season in 11 commercial flocks reared under a part-time grazing system. Milking season lasted from February to July. During that period, the diet of the animals shifted from indoor feeding, consisting of concentrate and forage, to an outdoor grazing diet. Lean dry matter, fat, protein, calcium, and magnesium contents increased throughout the milking season, as did rennet coagulation time, curd firmness, and curd resistance to compression. However, lean dry matter, protein content, and curd resistance to compression stabilized when sheep started to graze. Principal component analysis correlated curd resistance to compression and proteins, whereas curd firmness was highly correlated with fat content and minerals. Discriminant analysis distributed milk samples according to the feeding management. Curd firmness, fat, and magnesium turned out to be discriminant variables. Those variables reflected the evolution of the composition and coagulation parameters when fresh pasture prevailed over other feeds in the diet of the flocks. The present study shows that seasonal changes associated with feeding management influence milk technological quality and that milk of good processing quality can be obtained under part-time grazing.

Case study of a commercial sheep flock under extensive mountain grazing: Pasture derived lipid compounds in milk and cheese.

Terpenoid, fat-soluble antioxidant and fatty acid (FA) composition of pasture as well as those of milk and cheese from a commercial sheep flock managed under extensive mountain grazing in the east region of the Cantabrian mountain (Northern Spain) was investigated. The grazing period lasted for 2 months and ewes were at late lactation stage. Plants, feces, bulk milk and cheese samples were collected on two sampling dates. The abundance of the dominating botanical families in the mountain pasture prevailed in the sheep diet of the commercial flock. Major terpenoids and tocols in the pasture appeared as major ones in milk and cheese, whereas C18 unsaturated FAs in milk and cheese were derived from the intake of C18 polyunsaturated FAs which were prevalent in the pasture. No carotene was detected in the dairy samples but retinol (free or esterified), derived from the intake of ß-carotene present in pasture plants, was found in milk and cheese.

Effects of fasting and immobilization stresses on the phagocytic capacity of rat polymorphonuclear phagocyte monolayers.

The effect of two different types of acute stress (immobilization and fasting) on the polymorphonuclear leukocyte phagocytic function has been studied in male and female rats. With this aim, a subgroup of rats was under immobilization and fasting, another under complete energy deprivation and a third one (controls), exposed to the normal activity of the animal room, for 15 hours. The stress induction was assessed by controlling weight variations and gastric ulcers generation. Both stressors induced weight loss but only immobilization resulted in the development of gastric ulcer in all the animals studied. Phagocytosis was increased in male rats stressed by fasting and in immobilized female rats. In the remaining subgroups polymorphonuclear leukocyte cells showed a phagocytic capacity within the range of control values. Only comparison of the males group stressed by fasting with the male group stressed by fasting and immobilization showed a significant depression in phagocytosis.

Very-long-chain omega-3 fatty acids as markers for habitual fish intake in a population consuming mainly lean fish: the EPIC cohort of Gipuzkoa. European Prospective Investigation into Cancer and Nutrition.

OBJECTIVE: To assess the relationship between habitual fish intake and fatty acid levels in serum as well as in the LDL fractions of serum phospholipids and cholesteryl esters. DESIGN: Cross-sectional study. SETTING: Cohort of Gipuzkoa (Basque Country, northern Spain) included in the European Prospective Investigation into Cancer and Nutrition (EPIC) project. SUBJECTS: Random sample of 120 healthy volunteers of both sexes aged 35-65 y, divided into various consumption groups according to daily fish intake. METHODS: Data on habitual intake over the previous year was collected by trained interviewers by means of a computerized questionnaire based on the diet history method. Fasting venous blood samples were drawn and fatty acids were measured by gas-liquid chromatography. RESULTS: Lean fish accounted for 78% of all fish consumption in the highest consumption group (>115 g/day) and for 60% in the lowest (<31 g/day). The mean concentrations of omega-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA, C20:5, omega-3), and docosahexaenoic acid (DHA, C22:6, omega-3) in serum and in the LDL fractions of serum phospholipids and cholesteryl esters increased significantly from the lowest to the highest fish consumption categories. Fish intake showed a statistically significant relationship with omega-3 PUFA, EPA and DHA in serum and in the LDL fractions of serum phospholipids and cholesteryl esters both in the simple linear regression analysis and in a multiple regression model adjusted by age, body mass index (BMI) and vegetable intake. CONCLUSIONS: Habitual fish intake is reflected in the content of EPA and DHA in serum and in the LDL phospholipid and cholesteryl esters fractions. The concentrations of very-long-chain omega-3 fatty acids are useful biomarkers for dietary fish intake, mainly lean fish. SPONSORSHIP: Europe Against Cancer Programme of the European Union (agreement SOC 97 200302 05F02); 'Fondo de Investigaciones Sanitarias', Spanish Ministry of Health (FIS grant 99/0024-05); Government of the Basque Country; and 'Fundación Científica de la Asociación Española contra el Cáncer'.

Binding of coumarins to site I of human serum albumin. Effect of the fatty acids.

It is known that binding site I on human serum albumin (HSA) consists of a zone of two overlapping regions: the specific binding region represented by warfarin binding and the specific binding region represented by azapropazone and phenylbutazone binding. In this paper binding parameters to defatted HSA and to HSA with fatty acids (molar ratio of fatty acid/HSA = 4) were compared. High-affinity binding sites for warfarin, 4-chromanol, 4-hydroxycoumarin, coumarin, 3-acetylcoumarin and phenylbutazone (759,549 M-1 > Ka > 67,024 M-1) constitute binding site I on HSA. In this binding area defatted HSA can bind two molecules of warfarin, but the presence of fatty acids diminish the binding capacity of warfarin to HSA (2 > n > 1).

Modification of rat plasma lipoproteins induced by acute immobilization stress.

To determine the influence of acute stress on plasma lipids and lipoproteins, 66 Wistar rats (31 males and 35 females) were immobilized for 10 hours. Previously, these animals were deprived of food for another 10 hours. Because immobilization involves forced fasting, the control group consisted of 58 rats (30 males and 28 females) that fasted for 20 hours. The immobilized animals showed gastric lesions (94% of the males and 83% of the females). Plasma lipoproteins were separated by ultracentrifugation in the following densities: less than 1.006 g/ml (very low-density lipoproteins (VLDL)), 1.006 to 1.040 g/ml (low-density lipoproteins (LDL)), 1.040 to 1.063 g/ml (high-density lipoproteins fraction 1 (HDL1)), and 1.063 to 1.210 g/ml (HDL2). Measurements were adjusted according to hematocrit value. In male rats, immobilization caused a rise in total plasma cholesterol as a consequence of increases in the VLDL, LDL, and HDL1 fractions. In female rats, however, no significant variations were observed in plasma cholesterol, although there was a slight, but significant, increase in VLDL and LDL cholesterol. Immobilization caused hypertriglyceridemia in both sexes as a result of an increase in triglycerides in all classes of lipoproteins, except in HDL2 in both sexes and VLDL in males. Finally, the protein content of VLDL and LDL increased both in male and female rats; HDL2 levels decreased in female rats. These changes suggest an atherogenic character of stress caused by continuous immobilization during 10 hours.