ZA200103124B - A new composition and method for increasing production yield of agriculturally useful species. - Google Patents

Description

A New Composition and Method for

Increasing Production Yield of

Agriculturally Useful Species

Field and Background of the Invention

The present invention relates to an improved method for increasing production yield of agriculturally useful species, in particular mammalian species such as sheep, or avian species such as chickens, following administration of a composition comprising inhibin or a peptide derived thereof, conjugated to a protein carrier and emulsified with an adjuvant. The invention further relates to an increase in both animal fecundity and mean litter size as a result of treatment with the composition.

With consumer demands rising for high quality, environmentally sound products, sheep are becoming increasingly commercially important. Sheep produce a high quality milk; wool, a fiber with unique properties; and lamb, a nutritious, delicately flavored, low calorie meat. Sheep also offer a multitude of by-products used in the manufacture of many commercial products ranging from crayons to shampoos. Consequently, an improved method for enhancing sheep production yield is important for manufacturing sheep derived products.

There is a general need for a method for increasing ovulation and fertility in economically and agriculturally useful animal species, including mammals such as sheep and poultry species such as chickens, for example through the manipulation of hormonal factors within these animals to increase fertility. By increasing the level of certain such factors and/or decreasing the level of other factors, overall fertility of the animal can be enhanced.

In mammals and birds, FSH (follicle stimulating hormone) plays an important role in enhancing follicular growth and development. The enhanced ovulation rate is a consequence of an elevated FSH level in the blood. However, the hormone inhibin is known to act as an inhibitory feedback regulator of the FSH hormone (follicle stimulating hormone). Consequently, fertility can be increased by inducing hyper-ovulation in mammalian and avian species through the immuno-neutralization of endogenous inhibin (or its biologically active subunit).

Inhibin is secreted by granulosa cells of the ovary in the female and sertoli cells of the testis in the male. Inhibin consists of an «-subunit ( M,, = 18 kDa) linked by a disulfide bridge to one of two highly homologous B- subunit (approximately 14 kDa) to form either inhibin A (a-

PA) or inhibin B (a-pB). The fully processed form of the molecule has a molecular weight of approximately 32 kDa. Inhibin selectively suppresses the secretion of pituitary Follicle

Stimulating Hormone (FSH) and also has local paracrine actions in the gonads. The immuno-neutralization of endogenous inhibin by active or passive immunization lead to an increase in circulating FSH and can enhance ovarian follicular development and the number of oocytes.

There is thus a need for, and it would be useful to have, a method for increasing the fertility of agriculturally useful animals, including mammals such as sheep and poultry species such as chickens, through immunization against inhibin, which does not require large quantities or multiple injections of the immunogen, yet which would highly effectively promote hyper- ovulation of the animal and thus promote increased fertility.

Summary of the Invention

It is an object of the present invention to provide an economically effective method for enhancing the production yield of agriculturally useful animals, in particular mammals such as sheep and poultry such as chickens, through the administration of a novel composition for fertility enhancement.

An additional scope of the present invention relates to the use of substantially low concentrations of the immunogen, which is a conjugated inhibin or a fragment thereof. These concentrations are preferably in the range of from about 5 to about 500 micrograms immunogen per ml of composition, and more preferably in the range of from about 20 to about 300 micrograms immunogen per ml of composition.

It is yet an additional object of the present invention to provide a fertility-enhancing treatment for mammals, in particular sheep, which is effective under commercial farm conditions.

It is still another object of the present invention to provide a fertility-enhancing treatment for poultry animals, in particular chickens, which is effective under commercial poultry farm conditions.

It is a further object of the invention to provide a composition featuring inhibin or a fragment thereof, linked to a carrier protein emulsified with an adjuvant. Preferably, the immunogen includes the N-terminal sequence (amino acids 1-29) of the alpha sub-unit of bovine inhibin conjugated to keyhole limpet hemocyanin (KLH) at a ratio of 1:40 peptide/KLH.

According to the present invention, there is provided a method for increasing the production yield of an agriculturally useful species, the method comprising the step of administering to the species a composition containing an effective amount of inhibin or a fragment thereof,

According to another embodiment of the present invention, there is provided a 3 composition for enhancing the production yield of an agriculturally useful species, comprising: (a) inhibin or a fragment thereof: (b) a carrier protein for conjugation to said inhibin; and (c) an adjuvant for emulsification. .

Hereinafter, the term “animal” refers to any agriculturally useful species, including but not limited to, lower mammals, such as cows, sheep, goats and pigs; and poultry, such as chickens, ducks, geese and turkeys.

Description of the Preferred Embodiments

The present invention is of an economically effective method and composition thereof, for enhancing the production yield of agriculturally useful animals, in particular mammals such as sheep and poultry such as chickens, through the administration of a novel composition for fertility enhancement which contains substantially low concentrations of an immunogen, which is a conjugated inhibin or a fragment thereof. These concentrations are preferably in the range of from about 5 to about 500 micrograms immunogen per ml of composition, and more preferably in the range of from about 20 to about 300 micrograms immunogen per ml of composition.

The fertility-enhancing treatment of the present invention is useful for mammals, in particular sheep, and for poultry animals, in particular chickens, and is effective under commercial farm conditions. The composition of the present invention features inhibin or a fragment thereof, linked to a carrier protein emulsified with an adjuvant. Preferably, the immunogen includes the N-terminal sequence (amino acids 1-29) of the alpha sub-unit of bovine inhibin conjugated to keyhole limpet hemocyanin (KLH) at a ratio of 1:40 peptide/KLH.

The invention is illustrated by the following example which describes a preferred embodiment of the invention without imposing any limitations upon the scope thereof,

The method described hereinafter includes the following major steps. First, the immunogen was prepared. Next, the subject animal, such as sheep for example, was immunized using the immunogen composition, which was tested to determine optimal amounts and dosing schedules for administration. The results obtained were then analyzed to determine the specificity of antibodies raised against the immunogen and the efficacy of the immunization.

1. Preparation of the Inmunogen (@) Preparing Immunogen for Injection

A synthetic peptide corresponding to the N-terminal sequence 1-29 of the alpha-subunit of bovine inhibin (custom synthesized by SYPEP Ltd. Dublin, CA, USA) (hereinafter referred to as “the immunogen peptide) was conjugated to keyhole limpet hemocyanin (KLH, Sigma H- 2133) with glutaraldehyde (Aldrich 34,085-5) at a ratio of 1:40 peptide/KLH. The conjugate was dialyzed overnight against water at 4 °C. The dialysis water was replaced, and the conjugate was dialyzed another 4 hrs. at 4 °C.

In order to avoid aggregation of the material, which often occurs during peptide-KLH conjugation with glutaraldehyde, the conjugation process was carried out in the presence of sodium dodecyl sulfate (SDS) at a final concentration of 0.1%. The presence of SDS in the conjugation process enabled relatively lower concentrations of immunogen peptide to be used in the composition. Without wishing to be limited to a single hypothesis, presumably preventing the formation of aggregates resulted in more peptide antigenic determinants being accessible to the immune system of the subject animals, which in the experiments below were sheep.

Consequently, a lower dose of the immunogen peptide, with fewer booster injections, was required to induce a sufficient immune response.

The conjugated immunogen peptide/KLH was stored at -20 °C until emulsification with an adjuvant comprising 85% (by volume) mineral oil, 14.8% Span (emulsifier) and 0.2% Tween- 80 at a concentration of 25 microgram peptide in 1 ml of adjuvant. The emulsified composition was kept at 4 °C. (b) Evaluation of Different Immunogen Peptide Concentrations for Inducing

Immunity in Ewes

The titer of the antibody against the alpha sub-unit of bovine inhibin was quantified following injections of different concentrations of immunogen peptide. Five groups, each containing 5 Assaf milking ewes, were injected twice intra muscularly (i.m.) every two weeks,

The injected compositions contained 25, 50, 100 and 300 microgram of immunogen peptide and a control group receiving Phosphate Buffered Saline (PBS). Ten days after the second injection, all animals were bled. The serum was separated and kept at 20°C.

No substantial differences between the various immunogen peptide dosages could be seen with the ELISA assay (described below). All animals, except for the control animals, developed high anti-inhibin titer, when compared to the positive control of hyper- immune serum as shown in Figure 2. 5 (co) Quantification of anti-inhibin antibodies using the ELISA assay

The titer of the specific anti-inhibin antibody raised against the various concentrations of injected immunogen peptide was determined by an enzyme immunoassay (ELISA method), in which the wells were coated with immunogen peptide and the sheep antibodies were reacted with peroxidase labeled rabbit anti sheep IgG. The results were read at 405 nm after adding substrate.

The positive control was a “hyper-immune” goat serum against bovine inhibin alpha sub- unit (Biomakor Ltd, Israel), while the negative control was the pool of pre-immune serum from the tested ewes.

Figure 2 shows the results of the ELISA assay for different immunogen peptide concentrations. Even the relatively low dosage of 25 micrograms of the peptide was able to induce a good immune response as reflected by a high antibody titer. All results are compared to the positive control of the hyper-immune bovine inhibin serum and to the negative control serum obtained from the pre-immune ewes. (d) Specificity of Antibodies to Alpha-Sub Unit of Inhibin From Bovine Follicular

Fluid (BFF)

Specificity of antibodies induced by immunization of ewes against the synthetic alpha sub-unit (1-29) fragment of bovine inhibin was compared to the specificity obtained with natural inhibin originating from Bovine Follicular Fluid (BFF). As shown in Figure 1, the results demonstrate specific binding of the sheep immunogen-induced antibodies to the native inhibin,

The experimental method was as follows.

Ten ewes were twice injected i.m., with a period of two weeks between injections. The injections contained synthetic 1-29 alpha sub-unit of bovine inhibin conjugated to KLH and emulsified with an adjuvant. Ten days after the second injection the ewes were bled and the serum was separated and kept at -20° C.

(e) Western blot to BFF

BFF was separated on 10% SDS polyacrylamide gel together with molecular weight marker, and the fractions were transferred to nitrocellulose sheet by electroblotting. The nitrocellulose was blocked with dried, defatted milk powder in Tween buffer.

The blocked nitrocellulose was incubated with the anti-inhibin alpha sub-unit antibodies diluted with PBS. After washing in Tween buffer, blots were incubated with diluted peroxidase- labeled rabbit anti sheep IgG. The blots were developed using 4-chloro-1-naphtol as substrate.

As shown in the blot of Figure 1, lanes 1 and 2 contain BFF, while lane 3 contains the molecular weight marker (in thousands) is marked 3. Two bands of specifically bound antibody are shown, marked as “P” and “I”. The “P” band relates to unprocessed sub-unit precursor of inhibin (M.W. 56-58 kDa), while the “I” band is the alpha sub-unit of neutral inhibin (M.W. 32 kDa).

The results confirm that the antibodies obtained from ewes immunized against synthetic alpha sub-unit of bovine inhibin specifically bind to natural bovine inhibin fragments. 2. _ Immunization of Ewes with Immunogen Peptide Composition

The ewes used in this study were a commercial cross breed (German Marino x local

Assaf) at a moshav farm in the center of Israel. Ewes were kept in the shade all around the year, fed a commercially acceptable diet and given free access to water. All ewes in the study were tested at least 45 days after the last lambing.

For the experimental study, 122 ewes were divided randomly into 2 groups of 61 each.

The first group (treatment) was immunized with 1 ml of the emulsified immunogen peptide/KLH composition (25 microgram of immunogen peptide) by intra-muscular (i.m.) injection at the hip.

The second group (control) was injected i.m. with 1 ml of the adjuvant alone. Two weeks later a booster of 1 ml of the emulsified immunogen peptide/KLH composition, also containing 25 microgram of immunogen peptide, was injected i.m. to the treatment group. A second i.m. injection of 1 ml adjuvant alone was administered to the control group. On the same day, all ewes (control & treatment) were inserted with intravaginal devices (EAZI BREED CIDR G™ containing 300 mg progesterone, InterAg N.Z.) for 12 days. After these devices were removed, each ewe received 600 IU of pregnant mare serum gonadotropin (PMSG) (Synchroject Vetimex,

Holland) by i.m. injection. Blood samples of 10 ewes from the treatment group and 3 of the control group were taken. Blood was clotted and the serum separated and stored at -20 °C.

Two days after the injection of PMSG and 14 days after the booster, rams were introduced to the ewes at a ratio of 1:7. The rams were kept for three weeks. The number of pregnancies was then determined. Pregnancy rates were analyzed by Chi-Square test. Mean litter size was analyzed by Student t test. 3. Results Obtained Following Immunization of Ewes With the Immunogen Peptide

Containing Composition (2) Serum Anti-inhibin Titers

As shown in Figure 3, all ewes sampled from the treatment group which received injections of the immunogen had a significant anti-inhibin antibody titer while samples from the control group did not have such antibodies. The mean value of the results of the ELISA for the treatment group was 1.97 vs. 2.1 OD of the positive control and the control group was 0.22 vs. 0.24 OD of the negative control. (b) Pregnancy Rates . The pregnancy rates of the groups were determined by actual lambing between 140 to 175 days after introduction to the rams. The results were similar in both groups. 68% (40/59) of the ewes in the control group and 66% (40/61) of the ewes in the treated group became pregnant, as shown in Table 1 below. By the end of the experimental period, two ewes were removed from the control group because of illness. The calculation of the pregnancy rate was based on actual lambing. (¢) Mean Litter Size

The mean litter size of the treatment group was significantly higher compared to the control group, 2.1 lambs per ewe vs. 1.65, as shown in Table 1. This difference was reduced when only the lambs born alive were counted, although the results of the treatment group were still higher than the control: 1.9 vs. 1.6 (Table 1).

Those numbers reflect the number of ewes which conceived at the first cycle or at the following cycle. The three week period during which the rams remained in contact covered two ewe cycles, each such cycle lasting 17 days.

Table 1: Pregnancy rates and mean litter size of the two groups.

Group Pregnancy rate | Mean litter Size ad all

Control 68 (40/59) 1.65 a (66/40)

I Rl

Treatment 66 (40/61) 2.1b (84/40) . a *Lambs born alive a,b P<0.05

Eight out of nine lambs born dead in the treatment group werc from two ewes each carrying four lambs which had an abortion 5 days before the onset of lambing. It should be noted that common practice in for ewe management is to feed pregnant ewes during the last month of pregnancy with nutritional levels correlated to twin pregnancy (according to the NRC).

The nutritional requirements for triplet pregnancy are 10% higher compared to twin pregnancy.

Since the treated and control ewe groups were kept under the same nutritional conditions, the nine lambs of the treated group which were stillborn probably died from insufficient nutritional conditions. (d) Distribution of Litter Size

The distribution of litter size between singles, twins and triplets or more shows a clear tendency towards multi-lamb litters in the treatment group as opposed to the control. While only 5% of the ewes of the control had a litter of triplets or more, 27% of the ewes in the treatment group had triplets or more. This difference is reduced when only live bom lambs are counted.

Table 2 and Figure 4 show the distribution of litter size between groups.

Table 2: Distribution of Litter size between groups

EE EE Ee

Control 47.5% 47.5% 2.5% 2.5%

I EE Eo

Treatment 32.5% 40.5% 15% 12% *Lambs bom alive, (e) Fecundity

The overall fecundity of each group as presented in lambs born to 100 treated ewes and as calculated from the litter size was significantly higher in the treatment group compared to the control. Table 3 demonstrates the fecundity results.

Table 3: Fecundity of control and treatment groups. '| Control 1122 .

I EE

Treatment 138.6 fe *Lambs born alive

The calculation of fecundity was based on the total number of ewes treated. The

IS calculation of the number of lambs born to 100 ewes was made as follows: 100 x %Pregnancy x Mean litter size = number of lambs born/100 ewes (f) Summary of the Results )

The results demonstrate that the method and the immunogen composition as described herein clearly increased the litter size for the ewes to which the immunogen was administered.

The overall increase in litter size was mainly due to increase in the number of triplets and decrease in the number of singletons. Under normal farm conditions, this is a desired result as the ewes can easily carry pregnancies of triplets and the lambs are born viable. The composition of the present invention was also clearly able to induce a high specific antibody titer with very low doses (such as in the range of 20-300 micrograms per injection) of the immunogen peptide.

The field studies clearly show that active immunization of ewes with the composition of the present invention led to a three-fold increase in litter size. 4. ‘Evaluation of the Immunogen Peptide Composition of the Present Invention for

Improving Fertility in Rams

The titer of the antibody against the alpha sub-unit of bovine inhibin was quantified following injections of a composition according to the present invention containing immunogen peptide into Assaf rams. The rams were a local cross breed Awassi x frezien mix. At the beginning of the trial, samples were actively collected from the rams, by jumping on a teaser ewe, such that the semen was collected with an artificial vagina. Each time that semen was collected from a group of rams, all the rams in the group were jumped equally. At the beginning of the trial, the samples were examined for semen quality. The collected semen was diluted immediately with chemical ram diluent (RSD-1) and checked at SQA II B analyzer. The parameters which were examined included volume, concentration, motility, TFSC (Total

Functional Semen Concentration) and SMI (Semen Motility Index).

Six groups, each containing 5 Assaf rams, were examined. The ram with the lowest scores in each group was treated by being injected twice intra muscularly (i.m.) with 1 ml of the composition according to the present invention, with the injections separated by ten days. Nine rams were treated in total. The injected composition contained 50 micrograms of immunogen peptide, while the remaining rams received Phosphate Buffered Saline (PBS). Fourteen days after the second injection, semen was collected from all rams, and the quality was checked again with the same analyzer. In addition, at that time all treated animals and one untreated ram were bled. One ram died during the trial period. The serum was separated and kept at 20 °C.

The treatment of the rams with the composition of the present invention clearly increased various factors related to fertility, as shown in Tables 1A and 1B, with a comparison of each ram before treatment (Table 1A) and after treatment (Table 1B). Raw scores for the rams to be treated are given in italic type.

Table No. 1A: Semen quality before treatment

CE CR ry gy ey rg eg

ER CC I CH CC CC

CO CN A CC 2

I CC CL CN CO

A cA CN CLO ew | fs fms [oes joes

SR A J CN CON A

CR Ca A Co 2A

ER CC CR J CN CL

SR LC CN 2 a CC CC CN So

EAN CC J LJ CI LN

SR cc J LL CN EI CC

A A I A A a J Co CoE i

J —

FR Go J CO LL

A Cc CN C2 Ga

ES I CC

CR NS 2 A CA

SE CR LC I al

SE LN A A CN 2

EE CL ON CAN 20

EC I CL 0 CE LL i WO 00/25831 PCT/IL99/00585 .

Table No. 1A: Semen quality before treatment (con’t)

CA A 2 CC

CR LC CN C2 CA

FA I EC CL

RN LY CN HN CZ SC

SR I HC CI CA

SC EN LN 0 CE ch

Table No. 1B: Semen quality after treatment

Group [Ram [Volume [Concent. [Motility _ [SMI____[TFSC

I Pass [1 iss 79 ae Jo99

I 1396 Jo7 Tron Ps las Jo99 1 i213 Je7 340 edo [1369 rs 133 Jer [340 [999

Average] 1105 [155 [705 [3925 90925 4 lam [27 Jie J69 361 (725 4 [Ear N15 T1733 56 a2 [999 4 Ja1oM [15 ies 14 Jais Jos1 «9888 2 190 Jer lesz 999

Average] [1.925 16925 |75 |42325 [926 6 [Fyn Jos |is2 {70 374 [783 6 [5 2 Jie7 17a Jars 972 6 P24 Pp se Jin ]3g3 saa 6 1 Ns hea i3 Jaor oz 6 fios hh fier 7g lass ogg

Average] ~~ [146 [164 [132 la07 [soz [Mines 2 p04 Jss [522 Jo9o 5 [123 Nis sa in pis json 2 19934 Jos ios sz 493 lsgg 5 le448 [12 Joo fsa sui Jeo

Average] [13 1842 [794 [4648 [957.6 3 OPEN Jo N42 Jo B55 [700 3 fies | Joa 58 pes [318

Average] [1.625 [14025 [6825 [35625 [724.25 2 1816 fo7s [86 Js5 paz sos 2 98 Jos ~~ 43 Jeo 357 [708

Average] ~~ [0.89 109 era [291.8 [4128

Tables 2A and 2B demonstrate the relative quality of the semen of each treated ram in the context of the group before treatment (Table 2A) and after treatment (Table 2B). The relative quality was ascertained as a ratio of the value of each parameter for the treated ram, divided by the average of these values for the group of rams to which the treated ram belongs.

S

Table No. 2A: Index of semen quality before treatment

Ram [Volume [Concent. [Motility [SMI [TFSC . 1369] 1111] 091] 097] 094 0.87 1929 9934] 075] 101 io roi 1.02 166] 15] 078] oo 084 067 9888 421M | 08] 085] 094 089] 0.73 : 7315; 096] 065] 08] 068 042

S| 06] oq] w1is| oss 075)

Fluffi | 094] 088] 117] oo] od]

Table No. 2B: Index of semen quality after treatment. 1369 | _ L10] 1929F 112] 102] 103] 103] 1.03 9934] 062] 105] 1.03] 106] 1.04] 166] 123] 116] 1.07] vi 1.27] 9388] 1.04] 1.12] 1.08] 114] 1.08] 421M 7315) 112] 110 106] 109] 117] s| 137 woo] woo] 102] 1og

Fufi | 05s] 093] 096] 092 os]

Table 3 shows the index of semen quality for treated rams as a ratio of the quality before treatment (Table 2A) to the quality after treatment (Table 2B). Clearly, the quality of the semen increased after treatment for the parameters of Tables 2A and 2B. This particular ratio demonstrates the individual improvement of each treated ram.

Table 3: Ratio of the Quality Before Treatment to the Quality After Treatment for Treated Rams

RE Lc CC CN 2 LA

EE CC EC EL Lc

Ecc CC LC EEC a a

RC CC LCN LL LB

EC CC LE LN LE

Re CC LN J

FEE EC LEC EC LEC CL

EE CE CE EN EEC LLCO

Ea CE LE LS LCL LCA

Table 4 compares the average of treated rams to untreated rams before and after treatment. This compares the average value of the group before and after treatment. The results were analyzed by ¢ test to determine the significance of differences (a =P < 0.05, b = not significant), thereby demonstrating that before treatment, the rams to be treated had a statistically significantly lower quality of semen, as compared to the control rams. After treatment, this difference was eliminated. In some cases after treatment, the treated rams had semen quality that was slightly higher than for the control rams, but this was not statistically significant.

Table 4:

Before treatment After treatment

JE ell = PN = =

Catego: rams Rams P value rams rams P value

NS cl

Tables 1-4 clearly demonstrate that treatment with the anti-inhibin vaccine of the present invention, as previously described, improved the semen quality of rams with relatively low quality semen. This result is particularly significant, since the improvement was demonstrated for a large number of rams, which were shown to have statistically significantly lower quality of semen before treatment, as compared to the control rams, but to have the same quality of semen after treatment. Thus, the composition and method of the present invention successfully treat low semen quality in animals such as rams, which is of great agricultural and commercial importance.

The importance of comparing each treated ram to the control rams of the same group is that such a comparison overcomes any possible bias with regard to external factors, or to any intemal variances within each group. Table 3 shows the improvement for individual rams after treatment, while Table 4 shows the improvement within the groups of rams after treatment.

The parameters influenced most in the treated rams were motility, SMI and TFSC.

Volume and Concentration were less affected, possibly because they were relatively good before treatment.

S. Evaluation of the Inmunogen Peptide Composition of the Present Invention for

Inducing Immunity in Laying Hens

The anti-inhibin compositions and method of the present invention have been demonstrated to be effective in mammalian species, such as sheep, as described above. In order to examine the efficacy of the present invention in a non-mammalian species, specifically poultry, the effect of the composition was examined in laying hens. A flock of about 800 premature laying hens was housed in a one layer-poultry house and was divided into 3 groups of about 260-288 hens each. At the age of 18 weeks, before the onset of egg laying, Groups A and

B were vaccinated with 0.1 ml (5 micrograms peptide) of the anti-inhibin composition by intra- muscular injection; Group B was again vaccinated for a second time with this composition at the age of 20 weeks; and Group C was left as the untreated control.

At the age 20 weeks, a few hens started to lay sporadically. Subsequently, the data referring to performance of the 3 groups was collected. The examined parameters included an increased laying rate; increased cumulative egg production; increased egg weight and egg mass per hen; a reduction in the amount of food consumed per egg produced; and the persistence of the peak of laying. With regard to the last point, it should be noted that the rate of egg production various cyclically during the lifetime of the laying hen, such that the peak of laying represents the maximum rate of egg production per day for that hen. Typically, such a peak is reached at 90% daily egg production, or nearly one egg per day.

The results of the study demonstrated a clear improvement of egg production in comparison to the control, a significant improvement in egg mass per hen housed in comparison to the control, and a significant decrease in the amount of food consumed per egg produced, again in comparison to the control. Thus, the method and compositions of the present invention were shown to also be useful for increasing various parameters of the egg production of laying hens.

It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the spirit and the scope of the present i invention.

Claims (29)

1. What is claimed is:

   ) 1. A method for increasing the production yield of an agriculturally useful species, the method comprising the step of administering to the species a composition containing an effective amount of inhibin or a fragment thereof.
2. 2. The method of claim 1, wherein said inhibin is a synthetic peptide corresponding to an N-terminal sequence of an alpha-subunit of inhibin.
3. 3. The method of claim 2, wherein said N-terminal sequence includes amino acids 1-29 of said alpha-subunit of inhibin.
4. 4, The method of claim 2, wherein said inhibin is a bovine inhibin.
5. 5. The method of claim 1, wherein said inhibin is conjugated to a carrier protein.
6. 6. The method of claim 5, wherein said carrier protein is keyhole limpet hemocyanin (KLH).
7. 7. The method of claim 6, wherein said peptide is conjugated to said carrier protein with glutaraldehyde.
8. 8. The method of claim 7, wherein said conjugation is at a ratio of 1:40 peptide/KLH.
9. 9. The method of claim 8, wherein said inhibin is present at a concentration in a range of from about 20 to about 300 micrograms per milliliter of said composition.
10. 10. The method of claim 9, wherein said inhibin is present at a concentration in a range of from about 25 to about 50 micrograms per milliliter of said composition.
11. 11. The method of claim 10, wherein said composition contains an adjuvant for emulsification.
12. 12. The method of claim 11, wherein the species is a mammalian species.
13. 13. The method of claim 12, wherein the mammalian species is sheep.
14. 14. The method of claim 11, wherein the species is a poultry species.
15. 15. A composition for enhancing the production yield of an agriculturally useful species, comprising: (a) inhibin or a fragment thereof, (b) a carrier protein for conjugation to said inhibin; and (¢) an adjuvant for emulsification.
16. 16. The composition of claim 15, wherein said inhibin is a synthetic peptide corresponding to an N-terminal sequence of an alpha-subunit of inhibin.
17. 17. The composition of claim 16, wherein said N-terminal sequence includes amino acids 1-29 of said alpha-subunit of inhibin.
18. 18. The composition of claim 16, wherein said inhibin is a bovine inhibin,
19. 19. The composition of claim 15, wherein said carrier protein is keyhole limpet hemocyanin (KLH).
20. 20. The composition of claim 19, wherein said peptide is conjugated to said carrier protein with glutaraldehyde.
21. 21. The composition of claim 20, wherein said conjugation is at a ratio of 1:40 peptide/KLH.
22. 22. The composition of claim 21, wherein said inhibin is present at a concentration in

    PCT/IL99/00585 a range of from about 20 to about 300 micrograms per milliliter of said composition.
23. 23. The composition of claim 22, wherein said inhibin is present at a concentration in a range of from about 25 to about 50 micrograms per milliliter of said composition.
24. 24. The composition of claim 23, wherein the species is a mammalian species. :
25. 25. The composition of claim 24, wherein the mammalian species is sheep.
26. 26. The composition of claim 25, wherein the species is a poultry species.
27. 27. A method according to claim 1, substantially as herein described and illustrated. }
28. 28. A composition according to claim 15, substantially as herein described and illustrated. oo
29. 29. A new method for increasing production, or a new composition, : substantially as herein described. AMENDED SHEET