Iron and zinc availability to broiler chicken from mineral biofortified wheat

Abstract

This study was conducted to investigate the effect of mineral biofortified wheat with fungal phytase addition on iron (Fe) and zinc (Zn) availability in broiler chicken breast muscle and liver, their excretion in feces and digestibility in intestines. Furthermore, possible beneficial effect on broiler performance was studied. 90 day-old Ross 308 broiler chickens were placed in brooder cages and received commercial starter diet from day 1-7 posthatch and micromineral deficient starter diet from day 7-11 posthatch. On 11 day posthatch 70 randomly selected chickens were weighed, placed in individual cages and assigned to six experimental diets and one commercial grower diet. Experimental diets consisted of three different biofortified wheats as cereal components (difference is in the level of Fe and Zn in wheat), soybean meal, soybean oil and contained titanium dioxide as an indigestible marker. Three experimental diets were supplemented with recommended levels of fungal phytase. Broilers were weighed again on 19 day posthatch and number was reduced to 49 (7 replicants per diet). Feed intake and excreta output quantification was performed from day 19 until day 22 posthtach. On 22 day posthatch birds were killed by dislocation of their neck and samples of liver and breast muscle were taken. All samples were analysed by ICP-MS. Excreta samples were analysed to determine the excretion and digestibility of the Fe and Zn, and liver and breast muscle samples were analysed in order to detect content of Fe and Zn. No differences were observed for body weight gain, feed intake or feed conversion ratio among all different dietary levels of Fe and Zn. Fecal mineral excretion increased linearly with increased levels of Fe and Zn in biofortified wheat and it was significantly higher (P < 0.001) in control diet when compared to experimental diets. Apperent digestibility of Fe increased linearly with increased level of Fe in biofortified wheat, while digestibility of Zn decreased linearly with increased levels of Zn in biofortified wheat. Highest digestibility of Fe was in diet with 220 mg Fe/kg diet and highest digestibility of Zn was in diet with 37 mg Zn/kg diet. Supplementation of fungal phytase had no effect on broiler performance or mineral digestibility in this study. Ova studija je provedena u cilju otkrivanje uticaja bio-fortificirane pšenice sa dodatkom fungalne fitaze na dostupnost cinka (Zn) i željeza (Fe) u prsnom mišiću i jetri brojlera, te na njihovu ekskreciju u fecesu i razgradivost u crijevima. Moguĉnost pozitivnog efekta na performans brojlera je takoĊe bio jedan od ciljeva studije. 90 dan starih brojlera rase Ross 308 je postavljeno u kaveze i u prvih sedam dana života su hranjeni komercijalnom starter dijetom, a od 7-11 dana života su hranjeni sa starter dijetom koja je deficitarna u mikro mineralima. 11 dana života, 70 nasumiĉno odabranih pilića je izvagano i postavljeno u individualne kaveze te im je za ishranu dodjeljena jedna od šest eksperimentalnih dijeta ili komercijalna grover dijeta. Eksperimentalne dijete su sadržavale tri razliĉite vrste biofortificirane pšenice kao osnovnu komponentu (razlike su bile u razini Fe i Zn u pšenici), sojinu saĉmu, sojino ulje i titanium dioksid kao nerazgradivi marker. Tri eksperimentalne dijete su suplementirane sa preporuĉenim koliĉinama fungalne fitaze. Pilići su ponovo izvagani 19 dana života i broj pilića je smanje na 49 (7 replikanata po dijeti). Kvantitativno mjerenje unosa hrane i ekskrecije je obavljeno od 19 do 22 dana života. 22 dana života pilići su ubijeni metodom dislokacije vrata i uzorci prsnog mišića i jetre su uzeti. Uzorci ekskreta su analizirani u cilju odreĊivanja ekskrecije i razgradivosti Fe i Zn a uzorci prsnog mišića i jetre su analizirani u cilju odreĊivanja sadržaja Fe i Zn u njima. Nije uoĉena nikakva znaĉajna razlika u težini, unosu hrane i konverziji hrane izmeĊu razliĉitih Fe i Zn. Mineralna ekskrecija je linearno poveĉana sa poveĉanjem razine Fe i Zn u bio-fortificiranoj pšenici i bila je znaĉajno veĉa (P < 0.001) u kontrolnoj dijeti nego u eksperimentalnim dijetama. Razgradivost Fe je linearno poveĉana sa poveĉanjem razine Fe u bio-fortificiranoj pšenici, dok je razgradivost Zn linearno smanjena sa poveĉanjem razine Zn u bio-fortificiranoj pšenici. Najveĉa razgradivost Fe je uoĉena kod dijete sa 220 mg Fe/kg dijete dok je najveĉa razgradivost cinka uoĉena kod dijete sa 37 mg Zn/kg dijete. Suplementacija fungalne fitaze nije imala znaĉajan efekat na performans brojlera ili razgradivost mineral u ovoj studiji.