EFFECTS OF HUMIC ACIDS ON POULTRY UNDER STRESS CONDITIONS

The transportation of chickens from the poultry farm to the slaughterhouse causes stress conditions that influence the oxidative status of the whole organism and subsequently change the organoleptic properties of the meat delivered to the consumer. The aim of this work was to investigate how administering 0.6% humic acids to broiler chickens for a period of 42 days affects the level of selected enzymes directly involved in oxidative stress elimination. For the most objective estimation of the oxidative state, parameters were determined in liver and kidney mitochondria, and in the blood plasma. With regards to the chelating properties of humic acids, our interest was in monitoring the effects on the distribution of the transition metals Fe, Zn, Cu, Mn, which serve as cofactors of antioxidant enzymes. We have found that, under normal conditions, 42 days of humic acid administration do not cause significant metal redistribution. It has a significant effect on Se excretion, according to the pronounced deposition of Se in kidney tissue, without significantly increased activity of the corresponding enzyme. This led to compensation by changes in other antioxidant enzyme activities. This is a noteworthy finding, especially after administration of longer than 42 days. In conditions caused by sudden stress, according to the detected element levels, it is possible to expect a better response in the case of humic acid administration. The effect of humic acid supplementation appeared to be organ-specific and may ultimately be beneficial for the chickens' health, stress elimination and, finally, the quality of the meat. Key words: antioxidant enzymes; humic acids; chicken; metal cofactors; oxidative stress UCINKI HUMINSKE KISLINE NA PERUTNINO V STRESNIH POGOJIH Povzetek: Prevoz piscancev s perutninske farme v klavnico povzroca stresne razmere, ki vplivajo na oksidativni status celotnega organizma in kasneje spremenijo organolepticne lastnosti mesa, dostavljenega potrosniku. Cilj raziskave je bil prouciti, ali dodajanje 0,6 % huminske kisline v hrano pitovnim piscancem za 42 dni vpliva na aktivnost nekaterih encimov, ki so neposredno vkljuceni v urejanje in zmanjsevanje oksidativnega stresa. Za objektivno ocenjevanje oksidativnega stanja so se dolocevali parametri v jetrnih in ledvicnih mitohondrijih ter v krvni plazmi. Kelacijske lastnosti huminske kisline so bile proucevane s spremljanjem ucinkov na porazdelitev prehodnih kovin Fe, Zn, Cu, Mn, ki služijo kot kofaktorji antioksidantnih encimov. Ugotovili so, da v normalnih pogojih 42-dnevno dodajanje huminske kisline ne povzroci bistvene prerazporeditve kovin. Dodajanje pa pomembno vpliva na izlocanje Se glede na izrazito usedlino Se v tkivu ledvic, brez bistveno povecane aktivnosti ustreznega encima. To je privedlo do sprememb, ki so nadomestile aktivnosti drugih antioksidantnih encimov. To je pomembna ugotovitev, se posebej pri dodajanjih vec kot 42 dni. V pogojih, ki jih povzroca nenadni stres, je glede na ugotovljene ravni elementov mogoce pricakovati boljsi odziv pri uporabi huminske kisline. Ucinek dopolnjevanja s huminsko kislino se je izkazal za organsko-specificnega in je lahko koristen za zdravje piscancev, odpravo stresa in koncno kakovost mesa. Kljucne besede: antioksidativni encimi; humicne kisline; piscanec; kovinski kofaktorji; oksidativni stres