title: The effect of sodium zeolite A and cholecalciferol on plasma levels of 1,25-dihydroxycholecalciferol, calcium, and phosphorus in commercial Leghorns.
abstract: Three experiments were conducted to determine possible mechanisms involved in improving eggshell quality with sodium zeolite A (SZA) (trade name Ethacal feed component), and cholecalciferol (vitamin D3) by studying the effect of dietary supplementation of SZA and vitamin D3 on plasma 1,25-dihydroxycholecalciferol [1,25-(OH)2 D3], ionic calcium (Ca++), normalized calcium (nCa++), total calcium (TCa), percentage Ca++ to TCa (PCa++), pH, and phosphorus (P). In Experiment 1 (2 x 2 factorial arrangement of treatments), two levels of SZA (0 and .75%) and two levels of vitamin D3 (0 and 175 ICU/kg) were fed. In Experiment 2, five levels of vitamin D3 (100 to 500 ICU/kg) and two levels of SZA (0 and .75%) were fed using a 2 x 5 factorial arrangement of treatments. In Experiment 3, hens were fed two levels of SZA (0 and .75%). Blood samples were collected at 0 (Experiments 1, 2, and 3), 7, 14, and 21 h (Experiment 3) postoviposition (POP). In Experiments 1 and 2, decreasing vitamin D3 decreased plasma 1,25-(OH)2 D3 and P. Plasma TCa decreased when 0 ICU vitamin D3 was fed (Experiment 1), but was not affected by vitamin D3 level in Experiment 2. Supplemental SZA had no effect on plasma 1,25-(OH)2 D3, TCa, or P in Experiments 1 and 2. In Experiment 3, plasma 1,25-(OH)2 D3 and P peaked at 14 h POP, but Ca++ was lowest at 14 h POP. Circadian rhythms for plasma 1,25-(OH)2 D3, Ca++, and P were not affected by SZA. There were no significant effects due to dietary SZA on plasma 1,25-(OH)2 D3, TCa, Ca++, PCa++, nCa++, pH, or P.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Poultry Science Department, Auburn University, Alabama.
authors.forename: T J
authors.initials: TJ
authors.lastname: Frost
authors.forename: D A
authors.initials: DA
authors.lastname: Roland
authors.forename: D G
authors.initials: DG
authors.lastname: Barnes
authors.forename: S M
authors.initials: SM
authors.lastname: Laurent
mesh_terms: D000538:Aluminum Silicates / Q000494:pharmacology*; D000818:Animals; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood*; D002645:Chickens / Q000097:blood* / Q000502:physiology; D002762:Cholecalciferol / Q000494:pharmacology*; D004435:Eating; D004528:Egg Shell / Q000033:anatomy & histology; D004531:Eggs / Q000592:standards; D005260:Female; D010058:Oviposition / Q000187:drug effects; D010758:Phosphorus / Q000097:blood*; D011897:Random Allocation; D013046:Specific Gravity; D017641:Zeolites
chemical_list: D000538:Aluminum Silicates; D017641:Zeolites; D002762:Cholecalciferol; D010758:Phosphorus; D002117:Calcitriol; D002118:Calcium