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- ItemChanges in the Spectrum of Free Fatty Acids in Blood Serum of Dairy Cows during a Prolonged Summer Heat Wave(Basel : MDPI, 2021) Mylostyvyi, Roman; Sejian, Veerasamy; Izhboldina, Olena; Kalinichenko, Olena; Karlova, Lina; Lesnovskay, Olena; Begma, Natalia; Marenkov, Oleh; Lykhach, Vadym; Midyk, Svitlana; Cherniy, Nikolay; Gutyj, Bogdan; Hoffmann, GundulaThis experiment was conducted to study the effect of a prolonged hot period on the fatty acid (FA) composition in blood serum of dairy cows. Eighteen multiparous Holstein cows were randomly assigned to the hyperthermia group (HYP, n = 8) in August (summer season) and the control group (CON, n = 10) in October (autumn season). Blood from animals of the HYP group was collected in one heat wave, which was preceded by a long period of heat stress (HS, temperature-humidity index (THI ≥ 72)). Blood from cows of the CON group was collected under thermal comfort conditions (THI < 68). The spectrum of free fatty acids (FFA) in the blood serum was analyzed by gas chromatography. The concentration of FFA increased, including saturated FAs and monounsaturated FAs, in the blood serum of cows under conditions of prolonged HS. This was associated with the mobilization of FA into the bloodstream from adipose tissue, as a consequence of negative energy balance. An increase in the ratio of n-6/n-3 polyunsaturated FAs may indicate biomembrane dysfunction and adversely affect dairy cows. This study showed that prolonged periods of heat can affect the FA composition of blood. How much this leads to changes in the FA composition of milk and the quality of food products remains to be seen in further research.
- ItemIntestinal flow rates, absorption of felodipine from the small intestine and attributes of chyme collected at midgut from Labradors(Tübingen : Universitätsbibliothek Tübingen, 2023) Diebold, Steffen M.The objectives of the present study were (1) to investigate gastrointestinal hydrodynamics of Labradors as a model for human midgut (2) to examine various attributes of intestinal fluids in vivo and (3) to study the influence of hydrodynamics on the dissolution and absorption of a poorly soluble drug from various suspensions. Gastrointestinal flow rates were determined volumetrically using an aspiration method. Isotonic saline and 20 % glucose solutions were used to alter gastrointestinal hydrodynamics. Felodipine, a BCS class II substance, was suspended in these fluids. Osmolality, pH, bile acid concentration and drug solubility in various chyme samples were determined. Blood plasma levels of felodipine were recorded while gastrointestinal dissolution was ongoing. Fluid recovery at midgut fistula was significantly higher (>100 %) for glucose 20 % than for isotonic saline solutions (70 %). After administration of 200 ml glucose 20 % the (overall) grand median of differential gastrointestinal flow rates (DFR) was 8.3 ml/min.. Individual spike flow ranged from 20 up to 60 ml/min. Corresponding flow rates after administration of 200 ml isotonic saline were 35.0 ml/min. for the grand median including individual spike flows beyond 100 ml/min.. Within and between-dog variability in flow rate data was similar. In general, glucose solutions released more evenly. Following oral administration of glucose solution 20 % osmolality of intestinal fluids decreased within 40 min. from about 1000 mOsm. towards more physiological values of about 350 mOsm.. Saturation solubility of felodipine (Cs) in jejunal chyme after administration of either solution (saline or glucose) was determined to be about 10 (µg/ml) on average (median), exposing high variability with time! The intestinal solubility varied greatly within the course of an experiment. However, a strong correlation was observed between the aspirated fluid volume and the dissolved amount of felodipine confirming the well known relationship of Noyes, Whitney, Nernst and Brunner in-vivo. Grand median of pH in jejunal chyme of labradors was determined to be 6.68. Median values range from 4.38-7.62. The pharmacokinetic data showed a slight trend to differences based on particle size and on fluid administered.