CA1313471C - Zeolites in poultry feeding - Google Patents

Abstract

ABSTRACT
ZEOLITES IN POULTRY FEEDING

A method of improving the lean/fat ratio in broiler poultry by adding a small effective amount of zeolite A up to four weight percent of the feed, to the feed of the broiler pultry and regularly feeding the broiler poultry the feed containing the zeolite A.

Description

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Case 5061-F-Plus ZEOI~TES IN POULIRY ~ ING

me present m venti~n is in the gen`~ral field of poultry farmlng and relates to the feeding of poultry.
m e demand for poultry has expanded considerably sver the last decade. m e poultry indNstry has yrown frcm a hcme industry to a large scale manufacturing industry in which tens of thousands of chickens, turkeys and other birds are fed daily at single farms or poultry installations. This increased interest 10 in the poultry industry concerns not only the demand for eggs, especially chicken eygs, but also the demand for poultry meat such as t~rrke~s and chickens. For this reason there has been an increased interest in imprcving the quality of poultry and poultry products by means of modification in the poultry feed.
In our earlier work in this area of paultry feed, it was discovered that the inclusion of small amounts of zeolite A in a regular feeding program of poultry, such as chickens, increased the egg shell strength and this is described in U. S. patent 4,556,564. A related discovery is describe~ in U. S. 4,610,8B2 and consists of the use of small amounts of zeolite in the fe0d to improive the feed utilization efficiency and result in larger egg size.
Another beneficial effect found by the use of zeolite A
in the feed is decreased mortality rate of poultry and this is described in U. S. patent 4,610,883.
.

~311 3~71 Continued mvestigatio~ of the effects of zeolite A in poultry feed has resulted in the discovery of the follc~ing beneficial effects and positive results by the regular feeding of small amc~mts of zeolite A:

1. Calmer birds, reduced ac~ivity resulting in decreased production of body c~ecked eggs (layers) 2. Ex~ended lay cycle duration (layers and broiler breeders) 3. Reduced condemnation (broilers) 4. Improved feathering (broilers) 5. Improved resistance to hea~ stress (all poultry, but especially layers) ; 6. Increased male aggressiveness in breeding activity (breeders) ~he advantages of larger eggs, extended lay cycles and reduced condemnations are self-evident. Calmer birds produce more, less deformel eggs and lay with greater regularity. Stress in layers, as with most animals is a highly negative factor.
Imprc~ed feathering c~rrelates with healthier and stronger birds.
More recently, o~r studies have discovered that the inclusion of zeolite A in the feed of b milers r~ ts in improv-mg the lean/fat ratio in the edible carcassO With the increased desirability of less fat in a human diet, it has becc~e more and more important that ~he meat of poultry raised for food have a ; 25 high lean conten~ and a low fat content.
An article by CO Y. Chung et al from Nongsa Sihom Youngu ; Pogo 1978, 20 ~Livestock) pp. 77-83 discusses the effects of ~ cation exchange capacity and particle size of zeolites on the 13~ 3~7~l growth, feed efficiency and feed materials utilizability of broilers or broiling size chickens. Supplementm g the feed of the broilers with naturally occurring zeolites, such as clinop-tilolite, some increase in body wei~ht gain ~as determined.
Chung et al also reported that earlier results at the Livestcck Experiment Station (1974, 1975, 1976 - Suweon, Korea) showed that no significant difference was observed when 1.5, 3,and 4.5 per-cent zeolite was added to chicken layer diets.
U.S~ Patent 3,836,676 issued to Chukei Ko~aXine in 1974 discloses the use of zeolites as an absorbent for adhesion mois-ture of ferrous sulfate crystals in an odorless chicken feed com-prising such crystals and chicken droppings. I'he results were said to be no less than those m the case where chickPns were raised with ordinary feed.
EXperiments have been in progress in Japan since 1965 on the use of natural zeolite minerals as dietary supplements for poultry, swine and cattle. Significant increases in body weight per unit of feed consumed and in the general health of the ani-mals was reported (Minato, Hideo, Koatsugasu 5:536, 1968).
Reductions in malodor were also noted.
Using clinoptilolite and mordenite from northern Japan, Onagi, T. (Rept. Yamagata Stock Raising Inst. 7, 1966) found that IÆghorn chickens required less fcod and water and gained as ~uch weight in a two-week trial as birds receiving a control diet. No adverse effects on health or mortality were note1. m e foregoing Japanese experiments were reported by F. A. Mumpton and P. H.
Fishman in the Journal of Animal Science, ~ol. 45, No. 5 (1977) pp. 1188-1203.

~3~3~1 Canadian Patent 939,186 issued ~o White et al in 1974 discloses the use of zeolites having exchangeable cations as a feed component in the feeding of urea or biuret non-protein (NPR) c~mp~unds to ruminants, such as cattle, sheep and goats. Natural and synthetic as well as crystalline and non-~crystalline zeolites are disclosed. Zeolites tested included natural zeolites, chaba-zite and clinoptilolite and synthetic zeolites X, Y, F, J, M, 7., and A~ Zeolite F was by far the most outstanding and zeolite A
was substantially ineffective.
In a recent study at the University of Georgia, U.S.A., both broilers and layers were fed small amounts (about 2%) of clinoptilolite, a naturally occurring zeolite from Tilden, Tex~as. An article written by Larry Vest and John Shutze entitled "The Influence of Feeding Zeolites to Poultry Under Field conditions" summariz mg the studies was presented at Zeo-Agriculture '82.
A study by H. S. Nakaue of feeding White Ieghorn layers clinoptilolite, reported in 19~1 Poultry Science 60:944-949, dis-closed no significant differenc~s in eggshell stren~th between he~s receiving the natural zeolite and hens not receiving the natural zeolite.
In general zeolites are crystalline, hydrated alumlno-silicates of alkali and alkaline earth cations, having infinite, three dimensional structures. There are a wide variety of tyE~s. Scme types are naturally occurring and some of these types are made synthetically. Other types are made only syn-~hetically.

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Zeolites consist basically of a three-dimensional frame-wor~ of SiO4 and Al04 tetrahedra. m e tetrahedra æ e cross-linked by the sharing of oxygen atom~s so that the ratio of o~ygen atoms to the total of the alumlnum and silicon atoms is equal to 5 two or 0/(A1 + Si) = 2. 1`he electrovalence of each te~rahedra containLng aluminum is balanced by the inclusion in the crystal of a cation, for example, a sodium ion. m is balance may be ex-pressed by the formula Al/Na = l. The spaces between the tetra-hedra are occupied by water molecules prior to dehydration.
Zeolite A, which is not found in nature, is made synthetlcally, and may be distinguished from other zeolites and silicates on the basis of composition, X-ray powder diffraction patterns, and cer*ain physical c~laracteristics. m e X-ray patterns for these zeolites æe described below. Composition and 15 density are among the characteristics which have been found to be important in identifying these zeolites.
The ~2sic formula for all crystalline sodium zeolites may be represented as follows:

Na20 A1203 xSiO2 YH2o In general, a particul æ crystalline zeolite will hcave values for "x" and "y" that fall in a definite r~ngs. The value "x" for a particular zeolite will v~ry somewhat since ~he alum-inum atoms and the silicon atoms occupy essentially equivalent positions in the lattice. Minor variations in the relative num-25 ber of these atoms do not significantly alter the crystal struc-ture or ph~sical properties of the zeolite. For zeolite A, the "x" value normally f~lls within the range 1.85 ~ 0.5.

The value for "y" is ~t necessarily an invariant for all samples of zeolites. This is true because various ~xc~ange-able ions are of different size, and, since there is no major rha~e in the crystal lattice dimensions u~n ion exchange, the S space available in the pores of the zeolite to accommodate w~t~r molecules varies.
The average value for "y" for zeolite A is 5.I. The formula for zeolite A may be written as follows l.O ~ 0.2 Na2O A12O3 1.85 ~ 0.5 sio2 yH2O
10 In the formula, "y" may be any value up to 6.
An ideal zeolite A has the following formula:
(Na~lSiO4)12 27~I20 Among the ways of identifying zeolites and distinguish-ing them from other zeolites and other crystalline substanr~c, 15 the X-ray pcwder diffraction pattern has been found to be a use-ful tool. In obtaining ~he X-ray pcwder diffraction patterns, standard techni~ues are employed. m e radiation is the K doub-let of copper and a Geiger~ccunter spec~rometer or suitable radiation detector with a strip chart pen r~corder is used. The 20 peak heights, I, and the positions as a function of 2i where i is the Bragg angle, are read from a spectrometer chart or accumu-lated in computer memory. From thess, ~he relative mtensities, lOO VIol where Io is the intensity of the strongest line or peak and d the interplanar spacing in angstroms corresponding to 25 the recorded lines are calcNlated.
X-ray powder diffraction data for a sodium zeolite A are given in Table I.
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TABLE I
X-R~Y DIFFRACTION ~ATTEKN FOR Z~OI~TE A

h2 + k2 + 12 - (A) Io 1 12.29 100 2 8.71 70 3 7.11 35 4 6.15 2 5.51 25 6 5.03 2 8 4.36 6 9 4.107 35 3.895 2 11 3.714 50 13 3.417 16 14 3.293 45 16 3.078 2 17 2.987 55 1~ 2.904 10 2.754 12 21 2.6~8 4 22 2.626 20 24 2.515 6 2.464 4 26 2.414 >1 27 2.371 3 29 2.289 2.249 3 32 2.177 7 33 2.144 10 34 2.113 3 2.083 4 36 2.053 9 41 1.924 7 42 1.901 4 44 2.858 2 1.837 3 49 1.759 2 1.743 13 53 1.692 6 54 1.676 2 1.661 2 57 1.632 4 59 1.604 6 13~3~7~

The most significant d values for zeolite A are given in Table IIo TABLE II

MOST SIGNIFIC~NT d VPIUES FOR ZEOIITE A
5d Value of Reflection_in A

12.2 + 0.2 8.7 + 0.2 7.10 * 0.15 5.50 + 0.10 4.10 + 0.10 3.70 + 0.07 3.40 + 0.06 3~29 + 0.05 2.98 + 0.05 2.62 + 0.05 Cccasionally, additional lines not belonging to the pat-tern for the zeolite appear in a pattern along with the X-ray lines characteristic of that zeolite. This is an indication that one or more additional crystalline materials are muxed with the zeolite in the sample being testel. Small changes in line posi-tions may also occur under these conditions. Such changes in no way hinder the identification of the X-ray patterns as belonging to the zeoliteO
The particular X-ray techni~ue and/or apparatus em-ployed, the humidity, the temperature, the orientation of the powder crystals and other variables, all of which are well known and understocd to those skilled Ln ~he art of X-ray crystallog-raphy or diffraction can cause some variations in the intensities and positions of the lines~ These changes, even in those few in-stances where they become large, pose no problem to the skilled X-ray crystallographer in establishing identities. mus, the `'~ ' . . .

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X-ray data given herein to identify the lattice for a zeolite, are not to exclude those ma~erials which, due to some variable mentioned or otherwise known to those skillecl in the art, fail to show all of the lines, or shcw a few extra ones that are permis-S sible in the cubic system of that zeolite, or show a slight shiftin position of the lines, so as to give a slightly larger or smaller lattice parameter.
A simpler test describecl in "American Mineralogist,"
Vol. 28, page 545, 1943, permits a quick check of the silicon to 10 aluminum ratio of the zeolite. Accord 3 to the description of the test, zeolite minerals with a three-dimensional network that contains aluminum and silicon atoms in an atc~ic ratio of Al/Si =
2/3 = 0.67, or greater, produce a gel when treated with hydro-chloric acid. Zeolites having smaller c~luminum to silicon ratios 15 disintegrate in the presence of hydrochloric acid ancl precipitate silica. These tests were develo~ed with natural zeolites and may vary slightly when applied to synthetic types.
U. S. Patent No. 2,882,243 describes a process for mak-ing zeolite A ccmprising preparing a sodium-aluminum-silicate 20 water mLxture having an SiO2:A1203 mole ratio oE from 0.5:1 to 1.5:1, and Na20/SiO2 le ratio of Erom 0.8:1 to 3:1, and an H2O/Na20 mole ra~io of from 35:1 to 200:1, maintaining the mixture at a temperatuxe of from 20C. to 175C. until zeolite A
is form0d, and separating the zeolite A frcm the mother liquor.
It is an important object of the present invention to provide an improved feed formulation for broilers which contains a small amount, i.e., up to four weigh~ percent of th~ feed, of zeolite A.

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It is a principal object of the invention to prcvide a broiler feed containing zeolit A which impxoves the lean/fat ratio of the broilexs withou~ causing a deleterious ef~ect on the broilers.
Still another object of the invention is ts cost effec-tively increase broiler production.
Other objects and advantages of the invention will be more fully understood from a reading of the description and claims hereinafter.
It has been discovered that the addition of a relatively snkall amount of zeolite ~ to a regular or standard feed for broiling poultry, especially broiler chickens, effectively im-proves the lear~fat ratio of the broiler poultry with no signif-icant changes in feed consumption. Zeolite A is preferably added 15 in amounts of frcm 0.25 percent to 4.00 percent, arld more preferably less than 3.5 percent by weight of the total feed.
Broilers ar~ normally fed several different rations dur-ing their grcw~h period.
A typical feed preparation for large scale broiler poul-try operations broadly comprises the following by weight percent:

Corn 55-75 Soy Bean Meal 16-30 Limestone 0.5-1.0 Phosphates 0.6-2.0 25 Fat 2.0-7.0 Vitamins, Amino Acids Salt an~ Other Minerals 0.5-1.0 ll3~3~7~

A typical feeding scherne for broiler poultry includes a starter ration, a grower ration, a finisher ration and a with-dra~iL ration. mese rations will vary in cor~osition to match or othe~wise agree with the poultry's nutritional requirements as the poultry grow to maturity. m e withdrawal ration is free of antibiotics and the like so as not to leave any undesir~ble residue in the final meat product.
Zeolite A is added to each of such feed formulations or rations in small amounts by weight percent of up to four weight percent with less than 3.5 weight percent beir~ preferred.
Greater amounts r~y be used, but r~y deprive the broiLer pouLtry of the desired amount of nutrients. Greater amo~mts are also not likely to be cost effective. A preferred amount of zeolite A is frcm one-half to two percent by weight of the total feed formu-lation. A most preferred amount of zeolite A is about 0.25 toabout l.00 weight percent of the total feed for~ulation.
Using EIHACALTMfeed component, a ccmmercially availabLe sodium zeolite A, a number of tests were conducted to determine the effect of zeolites on the lean/fat ratio in broiler poultry.
20 Eq~AC~L feed component has the following typical characteris-tics:

Form Free flowin~ powder Color White Bulk Density, lb/ft3 23-29 Mean Particle Size, microns 3.0 Theoretical Xon Exchan~e Capacity, millie~livalents per gr~m (al~drou~s) 7.0 .~.... .. .

~ 3 ~ 3 ~ 7 :~

A typical chemical analysis is as follows.

E~r %
Sodium (Na) 12.6 Alumininum (Al) 14.8 Silicon (Si) 15.3 Oxygen (O) 35.1 Water of hydration (H20) 22.2 Heavy Metals less than 10 PPM
(Food Chemicals Codex Method) 10 Lead less than lO PPM
(Food Chemicals Codes Method) Ihe diet fed to the broilers consisted principally of corn supplemented with a soybean meal (S~M) and limestone.
Smaller amounts of fish m~al, dicalcium phosphate (DiCalP), a 15 syn~hetic amuno acid (DI,methionine), salt, a ~ cial vitamin and mlneral supplement for broilers (Micro-Mix~ were also added.
Each diet assured that the broilers received all of the required nutrients and minerals reccmmended by the Subc~nnittee on Poultry Nutrition of the National Research Council of the U.S.A.
Female broilers have a much higher tendency than males tGward excess fat deposits in their carcassesO It is therefore of utmost importance that fat be reduced, since females comprise a significant portion of ~he broiler meat consumed. Analysis of very low density lipoproteins (VIDL) in the blood correlates with 25 the lean/fat ratio o~ the OECaSS in broiler chickens. Studies of zeolite A diets compared wi~h conirols, i.e. similar diets not containLng zeolite A, are shown in ~he following table:

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Wei~ht PercentAveraqe Parts_~er Million VIDL in Blood Zeolite A m DietM~les _ Females n 24.1 2~.4 0.25 25.1 25.7 0.50 24.5 24.8 It can readily be seen that in female broilers, where fat is deposited more quantitatively the higher level of zeolite A in the diet results in lower VIaL le~els in the blood. Higher levels of zeolite A in broiler diets (1.0 weight perce~lt) have 10 been shcwn to give be~ter performance in weight gain and feecl eeficiency and should be expected to give added benefit with the lean/fat parameter also.
me term poultry includes all domestic fowl, namely chickens, turkeys, d~lcks, geese, an~ the like.
It can be appreciated that a wide variety of nutrients or foods may be included in the diets of broiler poultry. In a controlled envLronment, the poultry are only exposed to desired foods or food products. A typical ration progra-m for broiler poultry contains the following:
Starter Diet - Fed to Broilers 0-21 Days of Aqe Weiqht Percent Crude Protein 21.22 Calcium 0.86 Available Phosphorus 0.45 25 Synthetic Lysine 1 18 Me~hionine and Cystine 0.~7 Sodium 0.20 Pot3ssium 0.82 Chloride 0.31 30 Metabolizable Energy in K cal/lb 1440 ~ 3 i 3~

Grower Diet - Fed to Broilers 21-43 Days of ~qe Wei~ht Percent C~lde Protein 19.27 Calci~n O.80 Available Phosphorus 0.41 Synthetic Lys me 1.04 Methionine and Cyst me 0.82 Sodium 0.20 P~t ssium 0.74 10 Chloride 0.31 Metabolizable Energy in K cal/lb 1460 Withdrawa _ iet - Fed to Broilers ~3-50 Dk~ys of Aqe Weiaht Percent CXude Protein 16.85 15 Calci~n 0.60 Available Phosphorus 0.32 Synthetic Lysine 0.86 Methionine and Cystine 0.72 Sodium 0.20 20 Potassium 0.63 Chloride 0.32 Metabolizable Energy in K cal/lb 1480 The foregoing comEositions æe obtained from or include many of the following ingredie~ts-Grain and Processed ~rain bv-~roducts. Includes corn, corn hcminy, corn germ meal, barley, millet, oats, rice, rice hulls, rye, sorghum, wheat and wheat shorts. These are among the energy mgredients, mostly carbohydrates with s~ne proteins.
Plant ~rotein products. Includes soybe m oil mÆal, 30 barley malt sprouts, cocDnut meal, corn distillers grain, corn ~l 3 ~ 3 ~

glu~.en meal, cottonseed meal, pe~ seed, potato meal, peanut meal, rape seed m~al, sunflower meal, wheat germ meal, brewers' yeast.
All of these are protein sources.
Rouqhaqe or fiber. Includes dehydrated alfalfa, alfalfa 5 hay, alfalfa leaf meal and pasture grasses. These are all fiber sources.
Animal and fish by-~roducts. Includes blood meal, blood flour, dried huttermilk, dried whey, dried casein, fish meal, dried fish solubles, liver meal, meat meal, meat meal tank~age, 10 bone meal and dried s]um milk. Anchovies, herring and menhaden are sources of fish meal.
Minerals and svnthetic trace inq_edients. Includes vitamins such as B~12, A, pantothenate, niacin, riboflavin, K, e~c., DLrmethionine, choline chloride, folic acid, dicalciurn phosphate, magnesium sulfonate, potassium sulfate, calcium carbonate ~limestone, oyster shells), salt, scdium selenite, manganous oxide, calcium iodate, copper oxide, zinc oxide and D
activated animal sterol.
Molasses and animal fats are added to improve palat-20 ability and to increase or balance the energy levels.
Preservatives are also added such as, Ethoxyquin andsodium sulfite.
In general, a Eeed composition for broilers or broiler poultry should preferably contain by weigh~ percent the follow-25 ing:

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Weiqht Percen~
crude protein - at least about 14 crude fat - at least about 2 crude fiber - not more than about: 7 S calcium - about 0.5 to 1.0 phosphorous - at least about 0.2 iodine ~ at least 0.0001 sodium - about 0.1 to 0.4 chlorine - about 0.1 to 0.5 zeolite A - about 0.25 to 4.0 ~ s mentioned above, there are other beneficial effects which result from including a small amount of zeolite A in the poultry feed. For example, heat stress trials were conducted at University houses under controlled conditions of temperature.
15 Ihe first trial was aborted when the temperature went out of control and caused high mortality.
A second trial was conducted with 84 birds. The birds were 68 week old commercial laying hens of the white leghorn breed. m e birds were equally divided into two groups of 42 20 bir~s each. One group was fed a diet including zeolite A. The other group, the control group, was ~ed the same diet, but with-out any zeolite A. me group of birds fed zeolite A maintained production rate, shell quality and liveability when subjected to heat stress temperatures of 92-94F for .our weeks while the 42 control birds had reduced production rates, poorer shell quality ~L3~3~

and increased mortality. All three of the parameters were sig-nificantly different at a 95 percent co~Eide~ce level.
During two days of the final week of` a broiler chicken test conducted at another uni~ersity, the ten~erature in the broiler experimen~al house rose abc~e 98,F. Morkality among the broilers increased significantly during such two day period.
After the data was analyzed, it was found that the mortality rate among the control birds was 2.5 times that oE the birds being fed zeolite A in their diets. The followLng table summarizes the 10 mortality.

Weight Percent E~C,~LTM Percent Mortality During Iwo Feed Component in Diet Day Hiqh ~leat Stress Period o 2.00 tl-0.25 0 75 0.50 0.~,8 0.75 0.75 In another heat stress study, 168 birds (30 week old, young, mature laying hens) were divided into groups oE 84 birds each, with one group being fed 1.5 weight percent ETHACAL feed 20 component in an environmentally controlled room in which daytime and nighttime temperatures were held at ~5F and 85F, re~pec-tively during weekdays and held at a constant 85F on weekends.
m e other group (control group,~ was similarly fed, but without any ETH~CAL feed component in the diet. The most dramatic 25 result was the mor'cality difference. m irty of 'che control birds died dur mg the tests and only three of the ETHAC~L feed compo-nent fed birds diedO

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~ s another example of a heneficial effect, ~sm~
ETHACAL feed ccmponent, a commercially available sodium zeolite A, a number of tests were conducted to determine the effect of zeolites on male aggressiveness.

Calcium Zeolite A Salt Diet (Wt. %) (Wt. %~ (Wt. %~

1 2.50 0 0.21 2 2.50 0.5 0.15 3 2.50 1.0 0.09 l~e &alt in the diets was adju~sted to equal sodium levels to compensate for the sodium contained in the zeolite A.
The diet fed to the poultry consisted principally of corn ~upplemented with a soybean meal (SEM) and limestone. It also contained smaller amounts of alfalfa m~al, dicalcium phos-15 phate (DiCalP), a synthetic amino acid (DLrmethionine), salt, acommercial vitamin and mineral supplement for layer~s (Micro-Mix). Each diet assured that the broiler breeders received all of the required nutrients and m merals recommended by the National Research Council of the U.S. Subccmmittee on Poultry 20 Nutrition.

Diets contained normal amounts of calories per pound, protein, sulfur amino acids, calcium and phosphorous.
Data with regard to male aggressiveness ~as acquired by observing ~he behavior of the males as the ~arm workRr entered each pen. It i5 well known thkat male roosters will defend their te~ritory (the pen of hens) by attacXing any intruders into the pen, even human workers. It is also well known that the more 1313~

aggressive males have generally higher sperm counts than the more docile males and will inseminate more females and fertilize more eggs. Gver a two week period the workers recorded the pen num-bers m which ~hey were attacked by the males. m e pens were S rc~ndomly distributed in a lar~e poultry house. m e following table gives the average results for the 2 week period.

Percent Ethacal FeedPercent of Aggressive Ccmpone t in DietAttacks 'O O
0.5 33 1.0 60 m e data clearly show a linear response with zeolite concentration in the diet.
Again using Ethyl EZA~ zeolite, a commercially ~vailable 15 sodium zeolite A, a number of tests were conducted to determ me the effect of zeolites on production of body-checked eggs.
Two large poultry houses having identical hen popula-tions of 15,000 62 week old hens each were used. The diets fed to these old hens in the two houses were identical in every wa~
20 except that 0.75% zeolite A was added to the diet of the hens of o~e of the houses for a period of six weeks. Data was taken for three weeks prior to addition of the zeolite and again for two weeks after the six week test period. A summary of the data is shown in the following table:

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Averaae Percenta~e of BodY-ChecXs % Zeolite Pretreatment l~eatment Posttreatment in Diet Period _ Period Perio~ _ 0 23.51 16.7~ 18.74 0.75 22.10 12.2~ 25.15 The data shcw that during ~he pretreatment period the percent of body-checks was cibout equal in th8 two houses. During the treatment period the percent of body-checXs had drcpped almost 50 percent in the house in which the hens were fed zeolite 10 A in their diets; and during the posttreatment period when the zeolite A had been removed frcm the diet the percent of body-checks was again as high as they had been in the pretreatment period.
In another feeding test with 32,000 hens at a difEere~t 15 location the percentage of body-check eggs during the treatment period with 0.75% zeoli~e A in the diet was 44 percent lower than the pretreatment period and 57 percent lower than the posttreat-m~nt period.

Claims (7)

1. A method of improving the lean/fat ratio of broiler poultry characterized by feeding poultry a feed composition containing up to 4 weight percent of zeolite A.

2. A method as claimed in Claim 1, in which said zeolite A in said feed composition is in an amount of 0.25 to 2 weight percent.

3. A method as claimed in Claim 1, in which the amount of zeolite A in the feed composition is 0.50 to 1 weight percent.

4. A method as claimed in Claims 1, 2 or 3 in which the feed composition comprises proteins, fats, carbohydrates, minerals and vitamins.

5. A method as claimed in Claim 1, in which the feed composition comprises by weight percent the following:
crude protein at least about 14 crude fat at least about 2 crude fiber not more than about 7 calcium about 0.5 to 1.0 phosphorus at least about 0.2 iodine at least about 0.0001 sodium about 0.1 to 0.4 chloride about 0.1 to 0.5 zeolite A about 0.25 to 4.0

6. A method as claimed in Claims 1, 2 or 3 further characterized in that the feed composition comprises principally corn.

7. A method as claimed in Claim 6 further characterized m that the feed composition comprises by weight percent, 50-75 percent corn, 10-30 percent soybean mean, and 1-6 percent calcium carbonate.