| Abstract | Među žitaricama, zrno kukuruza sadrži najviše karotenoida, među kojima i β-kriptoksantina i β-karotena koji su provitamini vitamina A te tokola, spojeva vitamina E aktivnosti. Skladištenjem silaže visoko vlažnog zrna kukuruza, kiseli uvjeti stvoreni tijekom fermentacije mogu smanjiti sadržaj tih spojeva, ali i povisiti njihovu biodostupnost. Cilj ovog istraživanja je utvrditi utjecaj stajanja silaže visoko vlažnog zrna kukuruza na koncentraciju karotenoida, tokola i retinola u plazmi junica hranjenih istim obrokom tijekom četvero-mjesečnog razdoblja. Ukupno 10 junica križanki belgijskog-plavog goveda i holsteina, hranjene su obrokom s visokovlažnim zrnom (25%) i silažom cijele biljke kukuruza (56%) tijekom četiri mjeseca. Svakog mjeseca junicama je vađena krv, u odvojenoj plazmi je HPLC metodom odrešena koncentracija retinola, tokola i karotenoida. Navedeni spojevi određeni su u silaži visokovlažnog zrna i cijele biljke kukuruza te obroku uzorkovanim istog dana. Tijekom promatranog razdoblja nisu utvrđene značajne promjene sadržaja karotenoida i tokola u silažama i gotovom obroku, međutim, brojčane promjene određene su u silaži biljke kukuruza i obroku nakon trećeg mjeseca istraživanja. Najzastupljeniji karotenoid u plazmi junadi bio je β-karoten (0,33 - 0,59 μg/mL), a zatim u znatno manjim koncentracijama β-kriptoksantin, lutein te zeaksantin (> 0,05 μg/mL). Koncentracija α-tokoferola u plazmi junadi kretala se od 0,99 do 1,48 μg/mL, a retinola od 0,29 do 0,53 μg/mL. Koncentracija navedenih spojeva u plazmi varirala je tijekom razdoblja od četiri mjeseca, međutim, promjene nisu rezultat promjena u visokovlažnom zrna uzrokovanim kiselim uvjetima silaže. |
| Abstract (english) | Maize grain has the highest content of carotenoids among cereals, including β-cryptoxanthin and β-carotene, provitamins of vitamin A, and tocols, compounds of vitamin E activity. Acidic conditions created during fermentation may reduce the content of these compounds during prolonged storage high-moisture maize grain, however, these conditions can also increase their bioavailability. The aim of this study was to determine the effect of high-moisture maize silage storage on the concentration of carotenoids, tocols and retinol in the plasma of heifers fed the same ration during four-month period. A total of 10 Belgian blue-Holstein heifers were fed rations containing high-moisture maize grain (25%) and maize silage (56%) for four months. Once a month blood was taken from each heifer, and concentration of retinol, tocols and carotenoid was determined in plasma using HPLC method. These compounds were also determined in maize silage, high-moisture maize gran and ration sampled on the same day. Significant changes in carotenoid and tocol concentrations in forages and ration were not determined during trial, however, there were considerable changes in maize silage and ration after third month. The most abundant carotenoid in heifers’ plasma was β-carotene (0.33 – 0.59 μg/mL) while β-cryptoxanthin, lutein and zeaxanthin were in low concentrations (> 0.05 μg/mL). α-tocopherol concentration in plasma was from 0.99 to 1.48 μg/mL while retinol was from 0.29 to 0.53 μg/mL. Concentration of determined compounds in plasma varied during four-month trial, however, these changes were not result of changes in high-moisture maize grain caused by silage acidic conditions. |
