Alterations in liver and kidneys of chickens fed with high levels of sodium selenite or selenized yeast

Abstract

The experiment was carried out with 260 chickens divided into 13 groups, for 6 weeks. All chicken groups were fed with commercial mixtures, and selenium was added in their feed in the form of sodium selenite or selenized yeast at following concentrations: 0, 2, 5, 10, 15, 20 or 30 mg Se/kg. Three birds from each group were sacrificed on the 10th, 24th and 42nd days of the experiment. All internal organs were inspected and parts of the liver and kidneys were subsequently taken for pathohistological investigations. In birds fed with 2 and 5 mg Se/kg feed in the form of sodium selenite neither pathomorphological nor pathohistological alterations in the liver or kidneys were noticed at any of the monitoring intervals. In birds fed with the higher rates of inorganic selenium (10, 15, 20 or 30 mg Se/kg feed) certain pathohistological alterations occured that were more marked with the higher concentrations of selenium in the feed or after longer duration of intake. No alterations were noticed in the mentioned organs from chickens supplied with 2, 5, 10 or 15 mg Se/kg feed in the form of selenized yeast. Alterations of liver and kidneys were encountered only in birds treated with exceptionally high levels of organic selenium (20 or 30 mg Se/kg feed). In chickens fed with 10, 15, 20 or 30 mg Se/kg feed in the form of Na2SeO3, the liver was enlarged and of a lighter coloration, while pathohistological evidence varied between intracellular edema and necrotic changes. In kidneys, edema of the renal tubules was noticed and at the highest levels vacuolization and ballooning dystrophy of cells with loss of nuclei was found. In chickens supplied with 20 or 30 mg Se/kg feed in the form of selenized yeast pathohistological changes were less marked than in those fed with the same amounts of Se in the form of Na2SeO3.

Ogled je izveden na 260 pilića Hybro provenijence podeljenih u 13 grupa, u trajanju od 6 nedelja. Sve grupe pilića hranjene su komercijalnim smešama, a selen je dodavan u hranu u formi natrijum selenita ili seleniziranog kvasca u količini od 0, 2, 5, 10, 15, 20 ili 30 mg/kg. Po tri životinje iz svake grupe su žrtvovane 10., 24. i 42. dana ogleda. Izvršen je pregled svih unutrašnjih organa, a potom su uzimani delovi jetre i bubrega za patohistološka istraživanja. Kod pilića hranjenih sa 2 i 5 mg Se/kg hrane u obliku natrijum selenita nisu uočene patomorfološke ni patohistološke promene na jetri i bubrezima ni u jednom od ispitivanih vremenskih intervala. Kod pilića hranjenih sa višim nivoima neorganskog selena (10, 15, 20 ili 30 mg Se/kg hrane) uočene su određene patohistološke promene koje su bile izraženije sa povećanjem koncentracije selena i dužinom konzumiranja. U pilića koji su dobijali 2, 5, 10 ili 15 mg Se/kg hrane u obliku seleniziranog kvasca nisu ustanovljene promene na pomenutim organima. Promene na jetri i bubrezima su se javljale samo kod životinja tretiranih izuzetno visokim nivoima organskog selena (20 ili 30 mg Se/kg hrane). U pilića hranjenih sa 10, 15, 20 ili 30 mg Se/kg hrane u obliku natrijumselenita, jetra je bila uvećana i svetlije boje a patohistološki nalaz se kretao od intracelularnog edema do nekrotičnih promena. Na bubrezima je uočen edem bubrežnih kanalića, a pri najvišim dozama ustanovljena je vakuolizacija i balonirajuća distrofija ćelija sa gubitkom jedara. U pilića koji su dobijali 20 ili 30 mg Se/kg hrane u obliku seleniziranog kvasca, patohistološke promene su bile manje izražene nego kod onih hranjenih sa istim nivoima Se u obliku natrijum-selenita.