Change in body-weight and food consumption of rats on repeated feeding of a deficiency diet

(1)

Ondnnlepol)rt ./unnwl of l"denuor.tf ;·.;cience ruul Ani11111l

!urlusii.IJ . . l.rdl!/111' J:~. ·""'"7",,. I . .!uf_,J. J!J:j!J.

l'ri11t<·d i11 tliv Cllioll of Sont\1 .-Hri"" 1,-'. t\1(•

Gon.•rnlllent ]>rintL•r. l>n•tt~ri:t.

tion

Deficiency

in Body-Weight and Foo d of Rats on Repeate d

Consu m p- Feeding of a Cha nge

Diet.

Hy

.T. H. 1\I•:LLI•:H.\L\~\'. :-;< .. d iou of HiOl·hpmi>tn . ()nller.st<·poort.

I:\ lti:; stnd\· nn the ,-;niations in re:1dion of rats io di:ftPrent diets 1\l,loJnfiPld .(19:17) ohsPnPtl that "·hen a seriPs of nd.s of thP ~nllll' Ln•P1I nnd of :1pprllxinwtl'ly tlw sHIIIP ngP \\';t.s pbc-Pd 011 <I dd e<'tiYt' diP!·, iht•rp \\"t'l'P gTe:il indiYir1twl Ynri:Jtions in \\·t·ight los.s.

llepPti!iolh of tlw P:\Jit'rimPnb:; aftPJ' \u•ig·ht loss h:1rl l~PI'n restm·ed h\· a lll>rlll:ll did sltn\\·P<l that, on t ht• "·hole. thP a 11 im:ds \\·hil'h lost llHISt \Y<'ig·ht in tlw first insLin<·P <licl so :w·ain nncl rif'e n•rso. In <I furthN :-dud.\ Yre11c·h :111d Hloon1fiPid (l8Ti) si:tic•rl thai '· 1·nts \\llil'h IJ<l\.t' lo;;t ,,-,.ig·ht :1s ih<• n•,;ult of a <IPIPl'tiYe diet· and h:1,.,, ihl'll ht'l'll r<·:-d:Jn•rl in · 11111'111:11 ' In· shwk r:d ion .slw\1· :1 more l'<lpitl 'n·io·ht los.s i I 1111\\. pl:11.,.rl for :1 :-iP;'0111l t in1c• 011 t ht·' ,;:iJlle dl'f,.,.tin• diet 'l'his

· S<'l'OIIi"l:ir_Y rapid \\'t•igbt· lo;;s · m:1y lliT11r :1fter <IS long· an intt'IT:Ji :1.s SO ,l:J_,.,i hPt\1·(·1'11 the first and s<•r·011d pt~riod,; on c]pf.·r·ti,·p dir·t ''.

Tl11· :1 ut hor:-<. t hPrl'fon•, llPli<',.P t h:Ji t l11·\· lwn· P.~hl hli.-<ht•d \\·h:1t lll<l' p<'rll:tp,; Ill-' <':llll'rl :1 stat<· of ·' lntPut ,"]t·fici<-'llCY "- "l'tlfortunai<·l~:. ]."r<'lll'h :tnrl Hloundit>ld <lill no! Jlle:t,Ul'f-' the foorl int:JI;p anrl ih<·'Y <lid 111d shiP "·h<'iht•r tht>i1· :tnin1:il' "·erP l;qtt on :-il'l't'en' or "·lwtht'l.' tlw-'

"''rP :lllll\n•d :liT<'"' to ihPir PXr·reb.

ill<hiiiiii·h ^{: I '}~outh .\fril'n is ];llll\\.11 fur it.s p<'riorlil'<ll <lruug-lti..;

:111d :11hPr.-<t' .se:1son'. :1 l:nge ]wn·Pni:lg-t-' uf the• li.YPshwk in thi~ <·ountr_,. lllll'l ,;(llllPiimP.-< r•:-;ist fo1· pntlOllg'Pil pPriods on fo,Hl prohahly ,·pn·

rl~·fi,.i,•lli in <ll~t' or nwrP H'"l"'d . ..;. It ,;t1ch ]wrio<ls f"ll"". one nnot her i11 c]u,;p S\J('("I-•SSilll1. :l.S i~ .-<UIIil'\lllle~ the ('[).SP. <Ill(] if the oh~('r\":JtiOll of Vn·n .. ll and lll"ondield nl,;o hold" trup fm· f:1rn1 :1nin1:1b. it is iJ]wion.s th:Ji thi.-< plH'llllllli'llllll ,;]wllld hr of g-n·:1t intporiaiiC'<' io tl11· ]j,-p,_Jor·k iiidu.sll'\' itl this Cillllllry. 'l'hP foll11\\·i11g- <'XJll'l'illlellls ^\\^PI'I^' pblllll-'<1.

tl11·n·f"n'. "itl1 t·h0 "''.i<·1·t of furtiH·I· iii\.P.stig:JiiiJ~' thi, )ii"Ohlenl.

Yot111g· 1naltll'l' r:tls of the Sfllllf' hrPed S:lllll' ap:<' \\"1-'1'1° IISI'J] iII l he'P eXJll:'ri lllE'nh.

culon\· stor·k r:tlion n,;p,] in this lahorntorY.

<ll'f,.,.·ti''' di..t<. theY ''Prr·' feel for o;H' '21) 1

nnd of fipproxiiiJ<11<·ly tbr•

'l'he1· \YPrE' rai.S<··d on t b<' Hef'ure hei Ill.!' put on t b<•

>~·eek on t hP ~ynth..ti<.:

(2)

}'};E.DT~G OJ:' A DJ,;FICIEKCY DIET.

( e_,perimenta 1) stock ration used i11 these experimeub. The n1 I-s IYere then fed, in addition to distilled \Yate1·, diets* that were (lefective in Yariml~ respects. The number of rats on each diet varied from 12 to 24 with an even number of males and females in each group. Each rat wns housed in n separate cage an(l, with the ex(·eption of experiment IV, hpt on a IYire screen. 1'he animals '"ere weighed every other day but \Yere fed claily :tud the total individual food consumption f.or every two days recorded. The (;Omposition of the ~tork and dPfectiw diets is g-iwn in Table I.

'l'AHT.E T.

-==--==---_ --=--=-====c===c--====-:--'-===;=====;= - - - · -- - - -

Yello\1· maize meal. ......... Linseed oil meal. .. .. ... ''

Crude casein .. '' ..... .... Dried brow·ers' yea.Rt.

Lucerne n1eal. ...

Butter fat ......

Hcef liver (dried a,t 70° C.) .... Bone ash ... .. . . ^' . ^' Cod li vcr oil. ......... ... CaC0_{3 •}^,^,

0/aCl. ......... Dextrinized stnrch ...

Lard .... .. '

Salt 4or _-\gal' ....

- - - - -

Colon,- Stocl~

Diet.*

60 12 10 5 3 5 :2 ]

1 0·5 0·5

Experi- montA.l Stock Diet.t

20 8 7

5 l .Jo5 10 4

Diet low in Vitamins

and J[inemls.

:W

62·:5

~-~

:2 ^;)

* Plus tap water ;end fresh, whole milk <tel libitum.

J)ict _Jlllow

I

\'itamins, :\Iinerals

I and Bulk. ,

20

65 lil

Diet low in Proteins.

4 :2

:;

7:!.

10 4 :2

t The o:-cporimcntal stock ration used bv 'French and Bloomfield to restore thoir dop'loted animals to normal 11·eight was the same as that of Addis and co-worker~ (1!)26).

The mtion consists of maize starch 44, cA.sein ] 6, lard 14, cod liver oil 10. salt mixture (Osbome and }[C'ndel) 4, yeast JO, and lucPI'ne meal :2 parts by 11·oight. Thi,; mtion st>em,;

to be complete in every respect <>ncl no doubt not inferior to the experimental ~took ra.tion used in this labomtory. Therefore, it is improbable that the cli.fforence in weight lost by r<tts dn1·ing the first A.nd second trials on the dofccti1·e eliot was due to tho intermediate feeding by French and BloomfiPid of'' stock ration which was in itself not optimum in

C\'N_,. respect.

t Tho 0011\])(h;ition of s,dt ~0 was similar to that of StoC'nbock a.nd ~o]SOJ\ (.19:23) >>S 111odifiC'rl b_,-l.;comm and others (l9!l:{).

Altog·ether there ,,·ere six experimPld "· A description of th eoe is

~tn'n below :md the clatR obtained ou 11·eig·llt loss :mel food intake

~luring these t>xpe rim en h-; are snmm::n·isecl in' 'l'a hle II. Furthermore, the aYer·ag·e curYes of each group for 11·eight loss, food }H'I' rat per c.lr1)·.

·• All the synthetic food mixtures were stored in a refrigerator. and. in orr.lcr to prevent the dc,·elopmcnt of rancidity, only t•nouglL of Pach ration ttl last for about three to four claYs "·as 111ixecl nt a ti111o.

202

(3)

.I. H. l\ELLJ-:R)JA.\X.

<Ill(] food pel' 100 g'lll. rat per !lay, :trt' g"iYell i11 figure~ f LU \~l_ '['hE;

;;olid lines are cun-es during the :firRt trial on defective diet, the hro ken lines represent the sPrond trial. In all the experiments the initial bocly weigH is bkPn :ts 100 :Jn(l the changes ate expressetl in achwl gnm1s lost per (by.

8.rpe1iment I.

The 1:2 animals in this p;mup "·e1·e feLl the ,-itamin :nul lllineral lo"· rliet (but containing· 2·5 per cent. agar) for 46 clays when they lwtl lost on the avfrflge about 21 per cent. of theil' bod~- "·eig-ht. TheY '"ere then rPturned to the svnthetic stock diet until thev hnd rpg·n.inNl thPir fon1trr \\·eight ancl" were then again fed tlw clefici!•rtt diet for another 38 days. It is ot interest to point out that ~t>Yen rhys after the animals had been removed from the defective diet (after first trial ~~-ith weight loss of 21 per cent.) anrl placed on the Pxperimeutal stock diet, the_\· weighed on the average 20 grams more than when thev were first started on the deficient diet. In other

"·ords, the rats" made an increase of 41· 4- per cent. in ho1ly "·eig-ht ,,·hereas flurillg· the week preYious to the first trir1l on tht> 1lefed:in' diet they only gained 10·7 per cent. in body "·eig-ht ou the same diet. rrhe inchcat.ion of a stimulating after-effect of partial inanition on growth thm·efore supports the results of Kopec and Latysze~Yski

(J9d2) ·ohtainPd "·it.h mi(·e. The remadmbly quick recoYery is fllso re:fiPcted by ihe food intake. During the seven day:-; betiYeen the

fir.~l and second triab on defective diet the animflls consumed on the aYerage 15 · 3 g-rams of the stock ration per rat per da:v 01' 1· 5 grams JWr 100 grr1m rat pe1· day whereas during the week previous to the first trial •On defective diet they consumed 12 · 9 g-m. of the stock ration per rat per day or 6·1 gm. per 100 gm. n1t per day.

'l'he cunes in Fig. 1 sh o"· that the males lost less weight J uriug thP second trial on defective diet than chuing the first but also cousum2cl slig-htly more food during tbe second trial than during the first. l•'or the first 11 days the femnles also lost lPss in \\·eight a11d consumed more food per rat per chy c1uring the secon(1 trial than during- tlw first. After that time the curves crossecl and the general pid ure was ;just the reYer e. Because the llifferenr-P iH weight lost rluring first and second trir1ls on defective c1iet seems to be a true reflection of the di:ffel'ence in food intake, it is difficult to resist the oonclusion that, ull(ler the !•-xperiJneutal conditions, the change i11 we1gl1t on clefPchH• (liet '""" clue primarily to the l'hnuge in food intah.

'£.1:z1er-iment 11 .

. \.::; the results obtained in experiment I do not "Upport those of French and Bloomfield (1937), the ex-periment was n•peated with 12 male and 12 fem:•le rats. These animals were fed the same defir.ient diet used in cxperimPnt I for 25 days each dming- the first and Sf>cOn!l trialR.

From tl1e cunP~ giYen in Fig. 2, it i~ clear that t-he males again reacted as in the first experiment. The change in '"eig-ht curve of the female,; is in agreement with those found h_,. French and

203

(4)

1-'EEDT!\c: <H' .\ .IJEJ:'.LCll£1\CY J)IJ"l'.

Bloomfield in so faE· that the females lost app1·e<·iably nHln' in \Yeight duriug- the first 12 <la~·s of. the second trial than during the same period of the first. For 8 ·out of these 12 days the animals eYen ('Onsumed more f.oou per rat daily during the se('ond hial than during the first but, when expressed on the ba;;is of a unit l1ody weight (100 gm.), they actually consumed les~ cluring th<' c;econd i.han Juring the first tri<ll which may again help io account for tht> flifference in weight lost.

E.1:pe1'iment I I I.

The deficient ration u,;ed in tht> hi'O preYions t>xperimeni~

rliitei'P<l from the ration used by French and Bloomfield only in so f:1r <~s it also ('ontained 2·5 per cent-. of agal'. Because of. the difference between the results of these investigators aJI(l those of the 11-riter, it "as clf'cicled to o<>nlii- the agar from ihe diet in onler to see to \Yhat extent the ngar \Yas r<:'t>pousible for the cliscrepancy in results. The results obtai necl '"ith G male and 6 female rats are depicted graphir.nll,\· in Fig. 3. The males e~guin lost lese; \\·eight rluring the second irial ihan during the first where<~s then• wns han1ly any cliffprence uri \leen the weights lost hy the f<:'ntale,; during the first

<~ncl seconcl pPriods Oll <lefectiYe <liet; ancl it is eYident, therefore, that the agar ,,·ns not i he cause .of lhe <liffen-'nce in results obtnined iu 1 he t\\·o .ln horatm·i .. s ..

R.Vfleriment 7

r.

French :l!Hl Blootnfielc.l clicl not :>tate "·hdht'r their animah ,,·ere kPpt 011 ~nPens c.n nut alld it i.' po.~sible, therefore, that iheir auimals hud acce;:;;:; to thc•i!' o\\·n e:xneta and thai c·oprophngy lovk place. 1u order, therefor<". (o _..;tudy the dtPch of a free access to e:s:cret:. on the food inbke nn<l weig;ht lost on a <lefective diet, 12 ^nnimal^s^were h pt on vwod ~lt:l\·in~·s i.11 indiYirlual r·ages anrl fed the deficient diet u,;e(l in exjwrinwni Ill. Th'" c·llrYes giYeu in Fig. 4 sho\1· again that the eh::mge in \I"Piq·ht and foo<l intuke of th<:' nnimals clid not rli-ffrr n!Uch Jnrin::· ! lw fir->t :11Hl ,;econcl hinl~ ⁰¹¹ the . ..;:nne cliet-.

ln Yie\\· of the fact thai. duriug tl1P <h.\· RPa;:;olb ili<' pasbue in Suuth _\f'rinl is of ~nch a pom qu:~lit·y. ilw livesto('l;, mHler ra11ch

<·nnditioll'. 111ay not .onl.1· ;c;u:lft-r from a p<>riodicnl Yitam.in (e::;peeiall:--·

,-itamin . .::\) :~nd :1 '"i<le:-prc>acl 111ineral ('l'heiler nnd otlwn;, 1920. ]!)24.

;111<l dn Toit nncl t'O-\\'OI'J;pr,;, 1HT2 nucl 1935) bnt nbo From :1 prot<·In (1-:lenrici, J!·J;t!a; nn2h. Henriei Hlld Pottt'r, 1!)34, and Smuts and ulhers, ]!):19) .->horbge, a fourth group of G malc• anrl G feJII:lle rats \\'a«

iuelmled on ;t protein deficient ration. 'l'lH' nliion \\·n:; complete iu l"Yery re~peci ex<·ept tli:~t it \Y:l::i Yery lo\\' iu pn>tei lb. lt on I~· contai.uerl

:~bnni O·:l4 p<·'l' c·ent. HiirogeH ns Rnpplied b:--r the ye<~sL and lucen~<:>

meal su pplt>niPilt~. Tlw first an<l ,;econ<l periods on this rntioJJ

octnpiecl ~+ :~nd :pj <lays respc>cti,·t>ly. The curY<:'S giYen in l<'ig. ij

sltuw that, o~< the whole, lhere are no appreciahle differences i11 the perfonnnnC'e of tlte ;mimals dnring- the first nn<l second 1rials on the loll' protf'in diet.

204

(5)

FEEDING OF A DEFICIENCY DIET.

Number of Experiment.

I. ........ .

II .... .

III .......... .

IV ............ .

v ... . .

VI. ...... .

21 TABtE

su~BfARY OF DATA OK WEIGHT Loss ^{AND FooD}INTAKE OF GROUPS OF RATS DURIN(

Number of Animals.

6

12

6

Sex.

Males .......... .

:Females ..

Males ....... .

Females .............. .

Males .............. .

}'emales .............. .

:.\Iales ...•....

Females ....... .

Males .......... .

Dietary Deficiencies. Trial.

Vitp,mins and minerals ......... First ............ . Vitamins and minerals ......... . . Second ............... . Vitamins and minerals ...... . . . . . ... ·First . . . ......... . Vitamins and minerals ... . ... . ... ... . . Second ... . Vitamins and minerals ............ :First . . . . Vitamins and minerals........ t~econd ............... . Vitamins and minerals ............... . First ........... . Vitamins ar1d minerals.............. flecond ........ . Vitamins, minerals and bulk ......... First ............ . Vitamins, minerals and bulle ... f{econd ............. . Vitamins, minerals and bulk ............. First ..... . Vitamins, minerals and bulk ............. Second ......... . Vitamins, minerals and bulk ....... l'irst ............ . Vitamins, minerals and bulk ...... Second .......... . Vitamins, minerals and bulk ...... First ................. . Vitamins, minerals and bulk ....... Second .............. . Proteins ............... First ........... . Proteins. . . Second ...... . 6 Females........ Proteins ........................... . Yirst .............. . Proteins ........ . Second ....... .

6 Males ..... . Starvation but water allowed ........ l'irst fast .........

Starvation but water allowed ........ Second fast ...... 6 Females ... . Starvation but water allowed .... · ...... :First fast .......

Starvation but water allowed ....... S<olcond fast ............

* ^The^signs^- ^ancl

+

signify respectively

205-201

p205-206 p205-206 (cont.)

(6)

.T. H. J(ELLEIUIANS.

II.

' FIRST AND SECOND TRIALS ON vARIOUS DEFECTIVE DIETS AND STARV ATON 0

AVERAGE CHANGE IN BODY WEIGHT.* GRAND AVERAGE FOOD CONSUMPTION.

I

For first 12 days.

I

For first 24 days. For first 12 days. For first 24 days.

Weight

I I

^Grams. I

I

'

I

Per Rat Per 100 gm. Per Rat Per 100 gm.

Grams. Per cent. Grams. Per cent. per day Rat per day per day Rat per day

I

^Gra^ms^. ^Gra^ms. ^Grams. ^Grams^.

I

237·7 i'

- 14·4 - 6·1 -31·0 - 13·0 8·6 3·7 7·4 3·3

251·8/

+

^3·⁵

+

¹^·4 ^- ^5·3 ^- ^2·1 ¹¹^·8 ^4·⁶ ^10·3 ^4·1

178 ·4

·6

·), - 6·4 ^- 3·6 - 19·0 - 10·6 7·3 4·2 6·4

I

3·8

211·0 - 9·4 ^- 4·4 - 39·4 - 18·7 8·9 4·2 6·4 3·2

282·4 - 15·0 ^- 5·3 - 29·2 - 10·3 9·4 3·4 8·1 3·0

295·5 ^- 4·0 - 1·3 - 20·7 - 7·0 10·6 3·6 9·0 3·1

205·7 - 7·7 - 3·7 - 23·4 - 11·4 7·3 3·6 6·2 3·1

207·7 - 12·2 ^- 5·9 - 26·2 - 12·6 6·3 3·2 5·5 2·8

256·7 - 2·5 ^- 1·0 - 10·9 - 4·2 10·7 4·2 9·9 3·9

256·8

+

⁷^·9

+

³^·1

+

^1·1

+

^0·4 ¹¹^·6 ^4·4 ^10·6 ⁴^·0

172·8 - 2·5 - 1·5 - 5·3 ^- 3·1 7·6 4·5 7·5 4·4

179·5 - 0·5 - 0·2 - 9·3 ^- 5·2 8·1 4·5 7·0 4·0

273·0 - 8·5 - 3·1 - 10·3 - 3·8 9·5 3·6 9·2 3·5

282·8

+

^4·4

+

¹^·6 ^- ^0·⁵ ^- ⁰^·2 ^10·6 ^3·7 ⁹^·6 ³^·⁴

211·5 - 5·5 - 2·6 - 12·4 - 5·() 8·8 4·2 8·0 3·9

212·5 ^- 1·5 ^- 0·7 ^- 9·0 ^- 4·2 8·6 4·1 7·9 3·7

232·8 - 38·1 - 16·4 - 52·8 - 22·7 9·3 4·3 9·1 4·6

236·0 - 33·1 _I - 14·0 - 50·6 ⁱ - 21·4 8·7 3·9 8·6 4·2

198·9 - 28·2 - 14·2 - 41·9 - 21·1 7·9 4·2 Hi 4·4

199·3 - 25·9 - 13·0 - 39·2 - 19·7 7·8 4·2 7-fl 4·3

For first 8 days. For first 16 days.

409·4 - 79·8 - 19·5 - 140·1 - 34·2 - - - ^-

401·6 - 75·5 - 18·8 - 124·8 - 31·1 ^- - - ^-

298·9 - 57·7 - 19·2 - 99·3 - 33·2 - - - -

290·3 - 57·1 - 19·7 - 92·7 - 31·9 - - - --

loss and gain in body weight.

3 p205-206 (cont.)

(7)

.T. H. KEJ.LElOIANK.

E.vperiment T1.

In order to make the experimental condition,; as <lrastic as possible, a group of 12 (6 males and G females) adult rats \l·ere staned, except for clistillrd "·atm·, for lG days each during the fir.;t and second trialR. 'rhe curves Q'iven in Fig. G show that the animals lost \Yeight at an equd rate during the first all(l tiecond fasts.

SuM1IARY.

(1) Data are presented on the change in bo<l~- \YeigbL and food intake of young· mature r:tts during the first :tnd second trials on oliet.s rlefif'i.en l in minerals rmd vitamins; minPra ls, Yita mins and bulk; nncl proteins. Data are also gi.Yen on the loss in-body weight.

of rats during first aml second fasts.

(2) The results show that, under the experimental conditions, rats ,.-hich haYe lost "·eight as the result of a clefectiYe <liet, aurl have then been restored to normal 11·eight by stod: ration did 11ot sho1T, as was found by French and Bloomfield, a more rapid "·eight loss, if no"· placed for a se!'ond time on the same defectiYe diet. As a maHer of fad in the ma.iority of cases the aniuwls lo~t slightly less "·eight during thP second than during the first trial on defective rliet. This \\·as true no matter whether the rats had free aeecss to their o1nt excreta or not.

(3) Similarly, the food intake of the rats dicl not differ appreciably during successlYe periods on the same defectiYe r1iet.

CoKcr.uswN.

There seems to he a positive relationship between the change in daily foor1 consumption and the chang-e in body '"eight. It is probable, therefore, that the reason "·hy the animals of French and Bloomfield lost more rapidly in weight during the second than during the first trial on defecti,-e <1iet, "·as not because of a "latent deficiency" but because their animals con,;umed, on the whole, less food cluring the second than <luring the first trial on defcctiYe cliet.

vVhy that should haw been so, is cliffieult to say, b11t it is possible that the palatahility of their ration \Tas n-ot as good during- the second as during the first trial.

REFERENCBS.

ADDIS, T .. MCKAY, J.o:. iVL ~nd :UCKAY, L. L. (HJ2G). The effect on the kidney of the long continued administration of diets f'ontaining; an exc·ess of certain food eleritents. I. Excess of protein and cystine.

-1. Uiol. Ohe111., Yo\. 11, pp. 139-166.

BLOO:\[FTELD. :\. L. (4937). Individual variation· in suscepti:bilit_v to dietary deficiency . .J. :\litrition, Vol. 14, pp. 111-116.

DU TOIT. P . .L MALAN, A. I.. LOuW, J. G .. HOLZAPFEL. C. R., and ROETS. G. C. S. (1932). A studv of th" mineral content and feeding;

,-alue of natural pastures in the Union of South Africa (First Report).

18th Hep. DiT. Vet. Ser. and .4.nim. lnrlust., pp. -'526-571.

22 207

(8)

FEEDING 01•' A DEFICIENCY DIET.

DU TOl'l', P. J., MALA~, A. 1., LOCW, J. G., HOL%APFEL, C. R., allll ROETS, G. (Hl;35). A study of thE> mineral content and feeding value ol natural pasture~ in the union of South Afric·a (Third Report), UnderstepooTt .! . Vet. !::lei. and .lnim .fndust., Yol. 5, pp. 201-214.

!'RENCH, L. H. aud BLOOMFLKLD. A. L. (J937). " Latent Deficiency"

i11 rats: \'ariations in \\·eight loss on repeated fe<'ding of a dcl'cctivc diet, ,/. Xutril;.on. Vol. 14, pp. 117-129.

HE.l\lU.CL M. (1932). South Afriean Pastures: Their mineral and protein content, Fan11 i llfl in Sonth .-lf1·ica, Yol. 7. pp. 245-248.

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p. ll5i".

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South AjTica, Vol. 14, pp. 153-15:).

Tho protei 11 Fanning in

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;lgTic., So·ttth Af1·im, Vol. 1, pp. 221-224.

THEILEH, A., GREEK. H. H., nnd DU TOIT. P. J. (1924). Phosphorus in the 1 in· stock industry, .J. Dept. AgTic., South .i jTica., Vol. 8, pp, 460-604.

208

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Fig. 1.-Uraph of data from Experiment 1 (~ce text). The solid liues are curves during first trial 011 clef<><"tivt' diet., tiiP IJroken lines represe11t the second trial.

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Fig. 2.- Graph of data from Experiment l i (see text). The solid line~

are Clln·es d11ring first trial on defecti,·e diet, the broken lines represent the second triaL -

211

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Fig. 3.- Graph of data from Experiment Ill (see text). The solid lines are curves during first trial on defective diet, the broken lines represent the second tria I.

212

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Fig. 4.- Graph of data from E:<periment IY (sec text). The solid lines are curves during first trial on defel"tive diet, the broken Jines represent the

~ceoncl trial.

213

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