am j clin nutr 1969 hurwitz 391 5

8/3/2019 Am j Clin Nutr 1969 Hurwitz 391 5

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THE AMER ICAN JOURNAL OF CLINICAL NUTRIT IONvo l. 22 , N o. 4, Apr il, 19 69 , pp . 3 91 -39 5

P rin fr4 in U .S .A .

In tes tin a l C a lc ium A bsorp tion in th eL ay in g F ow l and Its Im portan ce in

i 1 #{ 149} 12 3a ic ium om eo sta sisSHMU EL H URW ITZ , PH .D ,4 A NDA . BAR , M.SC .5

T H E CA LC IUM META BO L ISM of the lay inghen is o f p articu la r in tere st d ue to its

in tensity , w h ich is m uch h ighe r th an inm os t o the r an im a ls stud ied .

Th e to ta l ca lc ium con ten t o f th e bo dy ofthe lay ing hen is 20 g an d tha t o f o ne egg is2 g , m ost o f w h ich is in th e sh ell. S ince ah en w ill lay nearly one eg g pe r day , its ca l-cium tu rno ve r ra te w ill app ro ach 0 .1 /day .S uch a h igh tu rn ove r ra te req u ire s ex -trem ely e ff icien t m ech an ism s fo r the as sim i-la tion of calc ium .

D uring m a tu ra tion , w ith in c rea sed ova r-ian ac tiv ity , the fo llow ing ch an ges w ith re -ga rd to calc ium m etabo lism take p lace :

a )Inc rea se in p la sm a ca lc ium (1) , fromabou t 1 0 m g /lOO m l to 25-30 m g/1 00 m l.A lm ost a ll th e inc rea sed calc ium is p ro -te in b ound (2 ) .

b ) Inc rea se in ca lc ium abso rp tio n (3 ) .c) S to rag e of ca lcium in the b one (4 ).

Th is is accom pan ied by the appea ranceo f m edu llary bon e in th e cav itie s o f th elo ng bon es. Th e m edu lla ry bo ne is ve rylab ile and its tu rn ove r rate is ex trem e lyh igh (5 ) .

d ) T he fo rm atio n of the firs t eg gsh ellinvo lves the ac tiv ity o f th e u terus . T h iso rgan is cap ab le o f tran sporting ca lc iuma t a ra te ex ceed in g 1 00 m g /h r .1 From the D ep ar tm en t o f A nim al S cience , T h e

V olcan i Ins titu te o f A gricu ltu ra l R esearch , R ehovo t,Israel.

Con tr ibu t ion from The V o lcan i Ins titu te o fA gr icu ltu ra l R esearch (N .U .I.A .) 1 968 ,erie s no . E.

S upported in p art by a g ran t from T he Un ite dStates D epartm en t o f A gricu ltu re , un der PL 480 .

S en ior Sc ien tist . R esearch A ssistan t.

Th is d iscus sion w ill be devo ted m a in lyto the fea tu re s o f calc ium abso rp tion .

PART ITION O F CALC IUM EX CRET IO NIt is ra th er u n fo rtu na te fo r the in vesti-

ga to r tha t, in b irds, u r ine and feces a rem ixed in the c loaca an d ex c re ted tog eth er;the re fo re , su rg ica l m ean s a re neces sary ino rd er to sepa rate these ex c re tions . A va ilab lesu rg ica l techn iques inc lud e co lostom y (6 )an d va rio us m e thod s fo r ex te rio riz ing th eure te rs (7 ) . T h e la tte r m eth ods re su lt inpo ly u ria and po ly d ipsia (7 ), w he reas co los -tom y does no t lead to d istu rb an ces in w a term e tabo lism and is the refo re th e p re ferredtechn iq ue in n u tritio n -ba lan ce stud ies .

C o los tom ies w ere pe rfo rm ed in seve ra lh en s. In som e cases, egg lay in g w as n o tin te rru p ted b y the su rge ry (8 ) . F eces, ob -ta ined from the n ew open ing , w ere co llectedin p la stic ja rs and the u rine w as co llectedin sta in le ss stee l trays p laced und e r the w ireflo o r o f the cage . T ab le I g ives th e ba lan cesheet fo r bo th calc ium and phosph orusfrom hens kep t o n a n orm al d ie t.

S in ce a ch icken w e ighs le ss than 2 kg ,abso rp tio n am oun ts to abo u t 1 ,00 0 m gcalc ium /kg pe r day , a ra te th at is a t lea st30 tim es g rea ter th an tha t o f a lacta tingw om an . S ince the yo lk co n ta ins on ly abo u t25 m g calc ium , m ost o f the abso rb ed ca l-c ium is secre ted in th e eg gsh ell. T h e u rin aryexc retio n , w h ile sim ila r in abso lu te am oun tto tha t o f m an , am oun ts on ly to abou t 10%of the to ta l abso rb ed ca lcium . T he refo re ,fo r p ractica l p u rposes, changes in reten tio n


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39 2 H urw itz an d B ar

#{ 176}M easured w ith the aid of Y .

TABLE IC alc ium and phosp horus ba lance o f

co los tom iz ed hens (8 )

Pa rame te r Ca lc ium,g/dayPhosphorus ,

g /day

In takeFecal excretionA pparen t absorp tion Urinary excretionReten tionbLo ss in eggBa t ancec

3 .000 .952 .050 . 2 21 .8 31 .750 .08

0 .570 . 180 .390 . 2 90 .100 .080 .02

a In take - fec al ex cret ion .App aren t abso rp tion - ur ina ry exc ret ion =

in take - to ta l e xc retion .Reten tion - lo ss in egg .

( in take m inu s to ta l exc retio n ) w ou ld large lyre flec t ch an ges in in tes tin al absorp tion .

T he requ irem en t o f th e ch ick en fo r p ho s-p1 o ru s is con side rab ly low er than th at fo rca lc ium , as th e she ll co n ta ins m os tly ca lc iumca rbon ate and on ly traces o f pho spha te .O ve r 9 0% o f the eg g phosp horus is fo undin th e yo lk . I t is o f in te rest to no te th atm o st o f the exc reted ca lcium is fo und inthe feces , w he reas m o st o f the ex cre tedph osph orus app ea rs in th e u rine .

RE LAT IONSH IP B E TW EEN CALCIUM INT AK EA ND CALC IUM ABSO RPT IO N

Typ ical resu lts o f ca lcium abso rp tio n as afunc tion of in take are p re sen ted in T ab leii. The d ata w ere ob ta ined w ith th e a id o fa n onabso rbed refe rence subs tan ce , y ttrium

TABLE IIC alc ium absorp tio n as a fu nc tion of in tak e

in h ens dur ing sh ell fo rm ation

Die ta ry Ca , % Ca in tak e m g/d ayC a a bs or pt io n

Absolu te , % o fmg/day i n t a k e

0. 591. 763 . 94

49 51, 7153, 920

40 01, 3102, 430

80 .876. 362. 0

91 , from hen s during she ll fo rm ation . T heexp erim en ts w ill b e desc rib ed in de ta il be -l ow .

C a lcium ab sorp tion inc rea sed w ith ca l-cium in take , w he reas th e pe rcen tage ab -so rp tion dec reased w ith inc rea sed in take .H ow ev e r, the d ec rease in pe rcen tage ab -so rp tion w as sm a ll in com parison w ith theinc rea se in abso lu te abso rp tio n and ev en a tthe h igh es t in take lev el stu d ied abso lu teabso rp tion had no t y e t reached a p lateau .T h is ind ica te s the h igh abso rp tion cap ac ityo f the lay ing h en .

REGU LAT IO N O F CA LC IUM ABSORPT IONThe len g th o f the lay in g cyc le in the hen

is abou t 25 -30 hr , w ith the she ll be ing de -po sited du rin g the la st 1 9 -20 hr . The refo re ,the p hys io lo g ical need fo r ca lcium is sub-jec t to la rg e varia tions.

F rom the resu lts o f ca lcium -b a lan ce ex -p erim en ts , T ay lo r (9 ) ca lcu la ted th a t d u r-in g sh ell fo rm a tion in te stin al calc ium ab-so rp tion cann o t m eet th e n eed fo r th ism ine ral, and bon e ca lcium m ust be m ob i-lized . H e pos tu lated tha t the ca lcium los tfrom bone du e to eggsh ell fo rm atio n w ou ldb e reg ain ed d urin g the tim e w hen no egg-she ll w as b ein g fo rm ed . T h is ca lcu la tionassum ed th at ca lc ium abso rp tio n rem ain edcon stan t th rou ghou t the lay ing cyc le . S tud -ie s m ad e by u s w ith bo nes (5 ) ind ica tedlittle chang e in bo ne ca lc ium du rin g thelay in g cyc le. Th is su ggested tha t bon e cal-cium w as n o t m ob ilized to a sign ifican t ex -ten t an d tha t the ex tra ca lc ium need ed fo rshe ll fo rm ation m ust have com e in to thebody by an inc rease in ca lc ium abso rp tion .

B ecau se ab ou t 6 h r elapse be tw een ca l-cium in take and ex cre tion an d b ecause o fth e d isco n tinu ity in feca l exc re tion , ba lancem e thod s a re n o t su itab le to eva lua te sh o rt-te rm chang es in ab so rp tion . W e , the refo re ,searched fo r a non ab so rbed re fe ren ce su b-stance to he lp stud y varia tio ns in calc iumab so rp tion d uring th e lay in g cy cle .

It w as fou nd (1 0) th at y ttr ium 91 w as no tabso rb ed and tha t its ra te o f passage


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C alcium Ab sorp tion an d H om eo sta sis 39 3

th roug h th e in te stin e w as the sam e as th a to f calc ium 45 . Y ttr ium 91 can there fo re beconsid e red a su itab le refe rence subs tan cefo r th e estim atio n o f ca lc ium absorp tio na t any leve l o f the in te stine . Th en w estud ied tw o lo ts o f h en s, fed d ie ts con tain -ing 1 .9 0 and 3 .5 6% ca lc ium . Th e leve l o f3 .56% is slig l1 tly abo ve the m in im um ca l-c ium requ irem en t, w h ereas 1 .90% can b econsid e red as a m od era tely de fic ien t d ie t.B o th d ie ts w ere un ifo rm ly labe led w ithy ttr ium 91 . Afte r 4 days on the ex pe rim en -ta l d ie ts , th e h en s w ere k illed an d the ir in -tes tin e s w ere sepa rated in to va rio us seg -m en ts . The con ten ts o f each segm en t w ereana lyzed fo r b o th ca lc ium and y ttrium 91 .Th e ne t ab so rp tion a t any lev el o f the in -tes tin e w as ca lcu la ted from th e ap pa ren tCa /# {1 76 } Y ra t io s .

In each lo t, som e hens w ere k illed duringearly sh ell ca lcif ica tio n , som e durin g la teshe ll ca lc ifica tion , and o the rs w hen no she llwa s be ing fo rm ed .

T he ov era ll ca lc ium ab sorp tion , ca lcu -lated from the C a/# {176} Yratio in the d ista l in -te stine , is g iven in T ab le III.

A s can b e seen , calc ium absorp tion due toshe ll fo rm a tion inc rea sed m ark ed ly , hav inga lm ost dou b led a t b o th lev e ls o f in tak e .M o reove r , the re w as little d iffe ren ce in ca l-c ium ab sorp tion be tw een pe rio ds o f ea rlyand late she ll calc if ica tion . T h is fin d ing hasbeen confirm ed recen tly by B ronsch and co-w ork e rs (1 2 ) , w ho observ ed tha t theabso rp -tion of a s ing le do se o f calc ium 45 w as al-m o st th ree tim es h ighe r w hen the egg she llw as b ein g fo rm ed than at the tim e w henth is p rocess d id n o t take p lace .

If o ne assum es a cons tan t flow of n u-trien ts in to th e in te stine (in o ur exp erien cethis is ach ieved b ecause feed is accum ula tedin th e c rop du rin g th e ea rly ev en ing feed in gpe rio ds) , it is ev iden t tha t th e need fo rca lcium durin g she ll fo rm a tio n can be m etby in creased in tes tina l ab so rp tion .

T h is exp e rim en t c lea rly dem on stra te s th eex istence o f an h our-to -h our reg u la tion ofca lcium ab sorp tion and the ve ry im po rtan t

TABLE IIIPercen tag e o f n et ca lc ium ab sorp tion in

lay ing hens, as in fluenced by sh ellfo rm ation and die tary c alc ium

S he l l c a l c i f i c a t i o nDi e t a r y Ca ,

3.56 1. 90

Non eEar lyLate

% Absorption40 .0 40 .168 .3 7 7 .372.4 71 .1

M easu red w ith the aid of1y

ro le p lay ed by the in tes tin e in ca lc iumhom eostasis in th e lay in g hen .

H ow ev er , a s w ou ld be expec ted , w h en th ed ie t w as de fic ien t in calc ium , even m ax i-m um absorp tio n w as inad eq ua te to m ee tth e ca lc ium need . U nde r th ose c ircum -stances th is need w as m e t by m obiliza tionof ske le ta l ca lc ium , as b ones from hen s fedsuch a d ie t exh ib ited la rg e ca lcium losses(13 ) . In tim e , such an im a ls w ill a lso ad ap tto the defic ien t d ie t b y red uc in g the irlo sse s o f ca lc ium in the eg gsh ell, w ith there su lt o f th in ne r egg she lls and a redu cedra te o f egg p rod uc tion (14 ).

EFFECF O F AN ACUTE DEPLET IONON CALC IUM ABSORPT ION

S ince the m oderate ca lcium dep le tion re-su lted in som e inc rease in ca lcium ab sorp -tion (see a lso Tab l e I), it w as o f in te re st tosee if in testina l ca lc ium abso rp tio n cou ld b efu rthe r stim u la ted by th e cha llenge o f anacu te calc ium defic iency . F or th is pu rp ose ,the c lassica l ba lan ce m ethod w as suff ic ien t,since w e d id n o t look fo r any rap id chang esin ab so rp tion (13 ).

Tw o g roups o f h en s w ere fed d ie ts con-ta in ing 1 .82 and 3 .92% ca lc ium for 6 days.Th is co n tro l pe riod w as fo llow ed by a 2-day dep le tion pe riod during w h ich a ll b ird srece ived a ca lcium -free d ie t (0 .12% ca l-c ium ). The rea fter , the h en s w ere p laced o nth e ir o rig ina l d ie ts fo r an add itiona l 6ay s(rep le tio n pe rio d ). C a lc ium ba lan ces w ere


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39 4 H urw itz an d B ar

TABLE IVEffect of a 2-day ca lc ium dep le tio n onhe

ca lc ium balance of lay ing hens (1 3)

D ie tary C a, % 1 .82 3 .9 3

P e r i o d Co n t r o l Reple -t i o n Contro l Reple-t i o n

Ca i n t a k e , g / d a yCa e x c r e t i o n , g / d a yCa r e t e n t i o n , g / d a yEg g Ca , g / da yCa b a l a n c e , g / d a yCa r e t e n t i on , %

2 . 0 60 . 7 01 . 3 61 . 5 6

- 0 . 2 06 6 . 2

2 . 0 20 . 5 21 .5 11 . 3 80 . 1 3

7 4 . 6

4 . 1 32 . 3 41 .7 91 . 7 70 . 0 2

4 3 . 4

4 .001 . 9 62 .041 . 4 30 . 6 1

5 1 . 3

co nduc ted du ring the co n tro l and rep letionper iods .

R esu lts o f th is exp e rim en t (T ab le IV ) in -d icate tha t bo th g roup s o f h en s resp ond edto calc ium dep le tion by a m arked in creasein re ten tio n , w hich is like ly to have resu ltedla rge ly from an increase in ab sorp tio n . T h is ,toge the r w ith the dec rease in she ll s ec retio n ,enab led the b irds to m ain tain a p ositiveca lcium balan ce du ring rep le tio n , thus al-low in g them to rebu ild the ir ske le ton . Inth e b ird s on the low er ca lc ium in take , th ere la tive ly h ig h abso rp tio n of ca lc ium hadno t qu ite reach ed th e p rob ab le m ax im umva lue o f 8 0% , ev en th ough th e b ird s hadbeen in a d istin ctly nega tive b alan ce du ringth e con tro l pe rio d , b u t an acu te sh ort-te rmdep le tion ra ised th e ca lc ium absorp tion toth is h igh er lev e l. T h is w ou ld sug gest th atth e re sp onse o f the in tes tine to the cha l-leng e o f ca lc ium dep le tion is to som e d eg reep rop ortiona l to the m agn itude of th e ch al-len ge , the absorp tio n of ca lc ium bein g afu nc tion of the d ieta ry ca lcium fed be fo rean d during the expe rim en t.

MECHANISM OF REGULAT ION O F

CA LC IUM A BSOR PT IO NW e h av e dem onstrated th e ro le o f the

in te stin e in calc ium hom eosta sis in lay in ghen s in tw o instances: re sp onse to an in -creased ca lc ium need due to she ll fo rm ation ,and re spo nse to the cha llen ge o f calc ium dep-r iva tion . It is n o t c lea r , h ow ev er , if th e

m ech an ism of th is re spo nse is th e sam e o rd ifferen t in these tw o instances.

U s ing in v itro techn iq ues, K im berg andco -w orke rs (1 5 ) sh ow ed th a t w hen ra ts w eresu b jec ted to a low calc ium reg im en , activ etransport of ca lcium deve lop ed in in tes -tina l segm ents w h ere no such tran spor t w asdem on strab le w hen the ra ts w ere on norm a lin takes . M adda iah and B ronner (16) sh ow edtha t the ap pearance o f the ca lc ium -b in d ingp ro tein (17 ) in th e in tes tina l m ucosa w as anin verse fu nc tion of d ie tary ca lc ium in take .It is m ost tem ptin g to ex trapo late thesefind in gs to the regu la tio n of ca lc ium ab-so rp tion by the in te stin e o f th e lay ing h en .

S uch an ex trap o la tion is ea sy if o neev ok es a ca rrie r-m ed ia ted ac tiv e transport.H ow eve r, re su lts o n th e in v itro up tak e o fca lc ium by th e in te stina l m ucosa o f lay inghens su ggest s im p le d iffusio n as the m ech a -n ism of th is transport (un pub lished da ta ).In v ivo s tud ies ((18) and unpub lished d ata )tend to support th is co nc lusion an d ex tendit to th e ov e ra ll p ro cess o f abso rp tio n .

W ith these f ind in gs in m ind it is s tillposs ib le a t leas t to specu late onh e m echa -n ism for regu la tion of ca lc ium ab sorp tion .H arrison an d H arriso n (1 9) c lea rly sh ow edthe m ucosa to cons titu te a perm eab ilityb arrie r fo r ca lcium . S chach ter (2 0 ) show edtha t th is p erm eab ility ba rr ie r in th e ratje ju num and ileum w as oxygen depen den t.I t thu s seem s po ssib le th a t th roug h som em etabo lic change th e pe rm eab ility o f them uco sa m ay b e m od ified and th us affec t th ereg u la tion o f in tes tin a l abso rp tion .

REFERENCES1. RIDDLE , 0. , AN D W . H . RE INHART . Stud ies on

th e ph ysio lo gy o f reprod uction in b irds. 21 .Blood ca lcium chang es in the rep roduc tive cyc le .Am . J . Ph ysio l. 76 : 660 , 19 26 .

2 . M cD oNALD , M . R ., AN D 0. RIDDLE . The effectof rep rod uction and e strogen adm in istra tion onth e pa rtit ion of calc ium , pho sph oru s an d n itro -g en in p igeon plasm a. 1. B io l . C hem . 159 : 45 5 ,1 9 4 5 .

3. T AYLOR , T. C ., AN D J. Ii. MOORE . The effec t o fh igh and low lev els o f d ie ta ry inorgan ic phos-pha te on th e prelay ing s to rage o f ca lc ium andphosph oru s and on com pos itio n o f the m edullary


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C alcium Ab sorp tio n and H om eo sta sis

an d cortica l b one in pullets. Brit . J. Nu t r . 12 :35 , 1 95 8 .

4. HURWIT Z , S . C a lc ium m etabo lism of pu llets a tthe onse t o f eg g produc tion , as in fluenced byd ieta ry ca lc ium leve l. Pou ltr y S ci. 43 : 1462 , 1964 .

5. HURWITZ , S. Bone com position an d C a 5 r et en tio nin fow l as in fluenced by egg form ation . Am . I.Physio l . 206 : 198 , 19 64 .

6. ARIYOSHI , S. , AN D H . M0RIM0T0 . Stud ies on th en itrogen m etabo lism in the fow l. 1 . Sep arationof u rine fo r nu tritiona l ba lance stud ies . u ll .N a tl. In st. A gr. Sc i. 1 2 : 3 7 , 1956 .

7. STURK IE , P . D ., AN D W . P . JoIN E R . E ffec ts ofcloaca l can nu la tio n on feed an d w ate r consum p-tion in ch ickens. P ou ltry Sc i. 38 : 30 , 1 959 .

8. HURWITZ , S. , AN D P. GR IM ING ER . Par tition ofca lc ium and phosphoru s excre tion in the lay inghen . Na tu re 189 : 759 , 1961 .

9. T AYLOR , T . C . C a lcium absorp tion and m etab o-lism in th e lay ing hen . In :u trit ion o f P igsan d Pou ltr y , ed ite d by J. T. M organ and D .L ew is. London: B utterw orths, 1 961 , p . 14 8 .

10 . H uRw ITz, S ., AN D A . BAR . R ate o f p assag e ofcalcium-45 and yttrium -9l a long the in testine,and ca lc ium absorp tion in the lay ing fow l. I.Nu t r . 89 : 311 , 1965 .

11 . HURWIT Z , S. , AN D A . B AR . Absorp tion of ca lciumand phosp horus a lon g the gas tro in tes tina l trac to f the lay in g fow l as in fluenced by d ie tarycalc ium and egg she ll fo rm ation . I.u tr. 86 :433 , 1965 .

12 . BRONSCH , K ., K . LORCHER AND B. STADL ER . Zu mC alc ium sto ffw echse l d es G eflu ge ls . Z . V eteri-n d rmed . 14 : 10 5 , 1967 .

39 5

13 . H uRw IT z, S .,AN D A . B AR . Calc ium dep le tion an drep le tion in lay in g hens . 1 . E ffec t o n ca lc iumin various b one segm ents, in egg she ll and inb loo d p lasm a, and on ca lc ium balance . PoultrySci . 45 : 345 , 1966 .

14 . HURWITZ , S. , AN D P. GR IMINGER . Observat ion s o nth e calc ium balan ce of la ying hens . . Ag r. Sc i.54 : 373 , 1960 .

15 . KIMB ERG , D . V ., D . ScHA cHT E R , AND H . S CHENKER .A ctiv e transport o f ca lcium by in tes tine : e ffecto f d ie ta ry calc ium . Am . I. P h ysio l. 200 : 1256 ,1961 .

16 . MADDA IAH , V . T ., AN D F. B RONNER . Calc iumtran spo rt and ca lc ium b in d ing pro te in (C aBP )o f ra ts . Sympos ium o n B iop hys ica l A spec ts o fPermeab il i ty , Jeru salem , 1 968 , p . 18 .

1 7 . T AYLOR , A . N ., AN D R . H . WASSE RM AN . V itam inD, - i nduc e d c a l c i um bi nd i ng pr o t e i n ; pa r t i a lpu r i f i ca t i on , e l ec t r ophor e t i c v i sua l i z a t i on , a ndt i s su e d i s t r i b ut i o n. A rch . B io chem . B iop hys . 1 1 9 :5 3 6 , 1 9 6 7 .

1 8 . HURWITZ , S. , AN D A . BAR . Activ ity , concen tration ,and lum en -b lood e lectro ch em ica l po ten tial d if-fe rence o f ca lc ium in the in testine of the lay inghen . J. Nu t r . 95 : 647 , 1968 .

19 . HARRISON , H . E ., AN D H . C . HARR ISON . VitaminD and p erm eab ility o f in te stina l m u co sa toca lc ium. Am . I. P hy sio l. 208 : 3 70 , 1965 .

20 . SCHACHT ER , D . V itam in D and the ac tive trans-p ort o f ca lc ium by the sm all in tes tin e. In :heTran sfer o f C a lc ium and S tro n tium Ac ros sB io log ica l M em b ran es, ed ited by R . H . W asser-m an . N ew Y ork : A cadem ic, 196 3 , p . 1 97 .

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