Effect Of Nixtamalized Maize On Phytic Acid, Iron, Zinc, Calcium, Total Phosphorus And Phytase Phosphorus Contents And The Anemia Status Of IDA Piglets

The present study was conducted to evaluates the effects of nixtamalization process parameters on the contents of phytic acid,iron,zinc,calcium,total phosphorus and phytate phosphorus of three types of maize varying in phytic acid content,and the effects of nixtamalized maize on the iron bioavailability,anemia status and growth performance of iron deficiency anemia(IDA) piglets.Two experiments were carried out to achieve that:Experiment 1:This experiment was undertaken to estimate the effects of lime concentration, cooking and steeping time on the contents of phytic acid,iron,zinc,calcium,total phosphorus and phytate phosphorus of three varing phytic acid-contained maizes.The phytic acid content in the maize were low phytic acid-contained(553.8±9.9 mg/100g),medium phytic acid-contained(737.0±12.3 mg/100g) and high phytic acid-contained(959.5±5.5 mg/100g),which were processed by five lime concentrations at 0,0.6,1.2,1.8 and 2.4%of maize weight,and cooked for 0,45,60 and 75 min to optimize the nixtamalization process parameters according to the greatest phytic acid loss in the three types of phytic acid-contained maize. Subsequently,under the optimized nixtamalization parameters,three types of maizes were steeped for 0,2,4,6 and 8 h.after each treatment,the changes of phytic acid, iron,zinc,calcium,total phosphorus and phytate phosphorus contents were determined.The results showed that:The phytic acid content was affected by different lime concentrations,all lime processing treatment groups with lime concentration over 0.6%had lower phytic acid content than the 0%lime concentration group(P＜0.05).The phytic acid loss did not differ among the lime concentration over 0.6%in low phytic acid maize(P＞0.05), whereas in the medium and high phytic acid maizes,the 1.8%and 2.4%lime concentrations groups significantly decreased the phytic acid content compared with the 0.6%lime concentration processing groups(P＜0.05).The cooking duration affected the phytic acid content,which was the lower after over 45 min cooking (P＜0.05),and cooking for 75 min further decreased the phytic acid than the 45 min cooking.After nixtamalization,the greatest phytic acid loss were 17.4%in the low phytic acid-contained maize(with lime concentration of 1.2%and cooking for 75 min),14.9%in the medium phytic acid-contained maize(with lime concentration of 1.8%and cooking for 75 min) and 27.5%in the high phytic acid-contained maize (with lime concentration of 1.8%and cooking for 75 min).The maizes calcium content was affected by nixtamalization processing,which were increased as the increasing lime concentration and the cooking duration (P＜0.05).The lime nixtamalization had an effects on the maize phytate phosphorus content,which were lower in lime concentration over 0.6%and cooking longer than 45 min than the groups with 0%lime concentration and no cooking(P＜0.05),but did not differ among the treatment groups of lime concentration over 0.6%or cooking duration over 45min(P＞0.05).However,the nixtamalization process did not affect the maize iron,zinc or total phosphorus contents(P＞0.05).Steeping treatment affected the phytic acid content,which was lower after 4 h groups than the 0 h group in the low phytic acid-contained maize,but 2 h steeping contributed to the significant lower phytic acid in the medium or high phytic acid-contained maizes than the other steeping group(P＜0.05).The phytate phosphorus content of the low phytic acid type maize did not change during steeping treatment(P＞0.05).However,the medium and high phytic acid content maizes had changed phytate phosphorus content after steeping,which was lower than 0 h after 4 and 2 h steeping respectively in the medium and high phytic acid content maizes(P＜0.05).Additionally,the calcium,iron,zinc and total phosphorus content of maize were not affected by the steeping treatment(P＞0.05).Experiment 2:Twenty Duroc×Landrace×Yorkshire(DLY) weaning IDA piglets,with initial body weight of 7.99±0.71 kg and 35±2 d,were used to examine the subsequent effects of the nixtamalized maize on the iron bioavailability,anemia status and growth performance of the IDA weaning piglets.The piglets of similar body weight,sex and hemoglobin concentration were randomly allocated to the control and treatment groups.The control group was fed the maize experiencing nixtamalization process of 0%lime concentration,cooking for 75 min and steeping for 4 h,while the treatment group was fed the nixtamalized maizes experiencing 1.8%lime concentration process, 75 min cooking and 4 h steeping.The body weight,feed intake,daily weight gain (ADG),daily feed intake(DFI) and feed conversion rate were determined very week. 2 mL blood were collected from jugular vein at 2 weeks interval for 4 weeks to determine hemoglobin concentration(Hb),packed cell volume(PCV),red blood cell count(RBC),hemoglobin repletion efficiency(HRE),hemoglobin-Fe(Hb-Fe) content The results showed that:Blood Hb concentration and Hemoglobin Fe(Hb-Fe) at the beginning and 2^nd weekend were not different between treatment and control groups(P＞0.05),however, Hb concentration at the 4^th weekend and throughout the experiment were higher in treatment than the control groups(P＜0.05).Blood PCV and RBC were similar between treatment and control groups at the four weeks period(P＞0.05),whereas the total increment throughout the experimental period were higher in the treatment group (P＜0.05).Nixtamalized maize diet affect the Hemoglobin repletion efficiency(HRE) of the IDA piglets,at the 2^nd weekend,the treatment groups had highter HRE than the control groups(P=0.074),at the 4^th weekend was higher in treatment than the control groups(P＜0.05)Nixtamalized maize diet had an effects on the ADG and DFI in the piglet suffered iron deficiency anemia,although no treatment effects were observed at the 1^st,3^rd week or through out the experiment period(P＞0.05),nixtamalized maize diet improved the ADG and DFI at the 2^nd and the 4^th week of the experiment compared with control group(P＜0.05).Feed conversion rate did not differ between the two groups of piglet suffered iron deficiency anemia(P＞0.05).These results demonstrated that:(1) Decreased phytic acid,iron and phytate phosphorus,and increased calcium content can be achieved during maize nixtamalization processing,but with the absence of the effects on zinc or total phosphorus contents.(2) Nixtamalized maize could improve the iron bioavailability,and growth performance,thus could be considered as an effective measurement protecting the piglet suffering iron deficit.