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During lactation, dairy cows undergo various metabolic changes that are reflected not only in milk yield but also in milk composition. This study aimed to determine the milk performance and composition depending on the stage of lactation and describe relationships between energy metabolism indicators (ketone bodies: β-hydroxybutyrate (BHB), acetone) in milk and selected indicators of milk performance and composition. The study was conducted on 1,909 dairy cows (Holstein, Czech Fleckvieh, and their crossbreds), which were divided into four groups according to the stage of lactation (early (6-100 days in milk), mid (101-200 days), late (201-305 days), and extended (>305 days)). The obligatory dynamics of the main milk components were found during the entire lactation, i.e., an increase in the protein content (from 3.30 to 3.76 g/100 g) and fat content (from 4.25 to 4.42 g/100 g) and a decrease in the lactose content (from 5.06 to 4.91 g/100 g). Significantly higher (P < 0.001) contents of ketone bodies were found in early and extended lactation than in mid and late lactation. The effect of lipomobilization on milk fat composition is documented by positive correlation coefficients between ketone bodies and long-chain fatty acids (FAs) and medium-chain FAs and negative correlation coefficients between ketone bodies and short-chain FAs. Positive correlation coefficients were calculated between ketone bodies and milk fat, citric acid, fat-to-protein ratio, and somatic cell score, and negative correlation coefficients were calculated between ketone bodies and milk protein, lactose, and free FAs. Our results demonstrate that currently often realized extended lactation in high-yielding dairy cows is similarly demanding as early lactation regarding energy metabolism and, thus, milk composition changes.

A fost efectuată evaluarea comparativă a hidrolizatelor papainice şi triptice ale ficocianinei şi Se-ficocianinei în urma separării prin metoda HPLC cu faze inverse pe coloana de ResourceTMRPC. A fost analizat profilul cromatografic al hidrolizatelor papainice şi triptice ale ficocianinei la separare prin gel-filtrare pe coloana de sefadex G-50. Spectrele UV-VIS ale fracţiilor peptidice obţinute la separarea prin gel-filtrare a hidrolizatelor ficocianinei au scos în evidenţă pre­zenţa peptidelor legate cu cromoforul.EVALUATION OF PEPTIDES SPECTRUM AT FRACTIONATION OF ENZYMATIC HYDROLYSATES OF PHYCOCYANIN AND Se-PHYCOCYANIN BY CHROMATOGRAPHIC METHODSA comparative evaluation of papain and trypsin hydrolysates of phycocyanin and Se-phycocyanin after separation by HPLC with reverse phase on the ResourceTMRPC column was performed.The chromatographic profile of peptides from the trypsin and papain hydrolysates of phycocyanin at separation by gel filtration on Sephadex G-50 column was analyzed. UV-VIS spectra of peptides fractions obtained by gel filtration separation of phycocyanin hydrolysates revealed the presence of chromopeptides.

Elaborarea unor procedee de obţinere a peptidelor bioactive din ficocianină prin intermediul hidrolizei proteolitice prezintă un interes sporit pentru cercetători în contextul utilizării acestora în calitate de remedii anticancer şi pentru alte proprietăţi terapeutice. Peptidele derivate din ficocianină ar putea manifesta proprietăţi terapeutice mult mai pronunţate comparativ cu ficocianina. În prezenta lucrare sunt studiate dinamica proteolizei ficocianinei cu papaina şi mecanismul de hidroliză a acestei proteine.Mechanism of proteolysis of C-phycocyanin, bioactive protein from Spirulina, under the action of papainThe elaboration of the procedures of obtaining of bioactive peptides derived from phycocyanin, as a result of it proteolytic hydrolysis presents great interest for researchers in the terms of theirs use as anti-cancer drugs and for other therapeutic properties. It can be assumed that peptides derived from phycocyanin could manifest more pronounced therapeutic effects compared to phycocyanin. Dynamics of phycocyanin proteolisis by papain, as well as mechanism of phycocyanin hydrolysis were studied in the present work.

Dezvoltarea şi aplicarea tehnologiilor de inginerie enzimatică, folosind enzimele pentru hidroliza ficocianinei şi producerea peptidelor bioactive, deschide noi perspective de utilizare a lor în calitate de agenţi anticancer, antimicro-bieni, antioxidativi, antihipertensivi etc. Lărgirea spectrului de peptide produse în baza enzimolizei ficocianinei poate fi efectuată prin utilizarea în acest scop a enzimelor proteolitice cu specificitate diferită. În lucrare sunt analizate spectrele UV ale hidrolizatelor triptice sumare ale ficocianinei şi descrise unele metode de separare şi analiză a fracţiilor peptidice din hidrolizat.ALGAL BIOACTIVE PEPTIDES AND THEIR PERSPECTIVE USE AS THERAPEUTIC AGENTSDevelopment and application of enzyme engineering technologies using enzymes for the hydrolysis of Phycocyanin and production of bioactive peptides opens up new prospects for their use as anticancer, antimicrobial, antioxidant, hypotensive agents. Diversification of the range of produced peptides can be performed by the enzymolysis and using of the proteolytic enzymes with diverse specificity for this purpose. The paper presents the UV spectra of summary tryptic phycocyanin hydrolysates and some methods of separation and analyzing of peptide fractions.