Investigation of the effect of Tribulus terrestris extract on some characteristics of the reproductive capacity of guinea fowl

Abstract

The effect of Bulgarian product Vemoherb-T (dry extract of Tribulus terrestris) on some characteristics of the reproductive capacity of Guinea fowl (Numida meleagris) was studied. A trial was conducted with 30 Pearl-gray Guinea fowls, at the age of 32 weeks, divided in two groups, 12 female and 3 male each. The birds from the two groups were fed the same mixture. The experimental group received the tested product once daily in a dose 10 mg/kg body weight for 12 weeks. The laying intensity, egg morphology and fertility, the weight of testes and ovaries were controlled. It was found a higher laying intensity (P<0.05), similarly higher egg weight (P<0.001), yolk weight (P<0.01), left testes weight (P<0.05) and egg fertility in the experimental group. No significant differences about egg white weight and yolk color between the both groups were found.

Full text

Biotechnology in Animal Husbandry 26 (3-4), p 259-266, 2010 ISSN 1450-9156
Publisher: Institute for Animal Husbandry, Belgrade-Zemun UDC 636.087.8
DOI:10.2298/BAH1004259N
INVESTIGATION OF THE EFFECT OF Tribulus terrestris
EXTRACT ON SOME CHARACTERISTICS OF THE
REPRODUCTIVE CAPACITY OF GUINEA FOWL
M. Nikolova
1
, S. Grigorova
2
, D. Abadjieva
2
, D. Penkov
1
1
Agricultural University – Plovdiv, Bulgaria
2
Institute of Animal Science – Kostinbrod, Bulgaria
Corresponding author: dessi_l@abv.bg
Original scientific paper
Abstract: The effect of Bulgarian product Vemoherb-T (dry extract of
Tribulus terrestris) on some characteristics of the reproductive capacity of Guinea
fowl (Numida meleagris) was studied. A trial was conducted with 30 Pearl-gray
Guinea fowls, at the age of 32 weeks, divided in two groups, 12 female and 3 male
each. The birds from the two groups were fed the same mixture. The experimental
group received the tested product once daily in a dose 10 mg/kg body weight for 12
weeks. The laying intensity, egg morphology and fertility, the weight of testes and
ovaries were controlled. It was found a higher laying intensity (P<0.05), similarly
higher egg weight (P<0.001), yolk weight (P<0.01), left testes weight (P<0.05) and
egg fertility in the experimental group. No significant differences about egg white
weight and yolk color between the both groups were found.
Key words: Guinea fowl, Tribulus terrestris, egg production, egg fertility
Introduction
The use of synthetic hormones as stimulators of reproductive performance
in animal husbandry practice has a negative cumulative effect in animal products
meant for the market. Therefore, their further use is not preferable because of the
detrimental effect on human health. An alternative of synthetic hormones is the use
of plant extracts. They are seen as natural feed additives, have been generally
proven effective, non-toxic and well accepted by the public. Plants can produce
phytochemicals with sex enhancing potency, able to stimulate reproductive
performance of animals and birds. Semerdjiev et al. (2008) reported a positive
effect of the product “Xtract” (multifunctional feed additive, which contains the
following plant substances: Capsacin, cinnaldehyde and calvacrol) on egg fertility
in hens. Bulgarian nutritional additive “Ovocap”, which contains capsacin,
carotene and other biologically substances improved the reproductive parameters in
cows (Petkova et al.,2008) hens and turkeys (Kitanov et al., 2003).

M. Nikolova et al.
260
The extract of the herb Tribulus terrestris is one of the most popular
phytoproducts, which contains saponins of the furostanol type, termed
protodioscin. During the recent years experiments with various farm animals (rams,
pigs, cocks, rabbits) proved the beneficial effect of Tribulus terrestris extract on
sperm quality, sexual behavior and fertilizing ability of sperm. However, there are
no reports in the available literature concerning the effect of Tribulus terrestris
extract on other fowl species (except hens).
The aim of this work was to investigate the influence of the product Vemoherb
T (dry extract of Tribulus terrestris L), produced by Vemo Ltd, Sofia, Bulgaria on
some characteristics of breeder Guinea fowls reproductive capacity.
Materials and Methods
The present study was carried out in the period April-June - 2008 at the
Experimental center of Animal Science Department, Agricultural University -
Plovdiv with 30 Pearl gray Guinea fowls at the age of 32 weeks, raised under
extensive conventional method of production on a deep litter pen. The poultry were
randomly divided in two groups – control and experimental, 12 female and 3 male
each. The trial lasted 13 weeks – one week adaptation and 12 weeks experimental
period. All birds received the same mixture for breeder Guinea fowls, containing
17.17% crude protein, 4.21% crude fat, 5.41% crude fibre and 11.80MJ/kg
metabolizable energy. The nutritive value of the diet was determined by the
Weende method. The experimental diet was supplemented with Bulgarian product
Vemoherb-T in a dose of 10mg/kg body weight for a period of 12 weeks.
Daily laying intensity and capacity were controlled throughout the trial.
Forty eggs from each group, laid within a few consecutive days were taken at the
beginning, in the middle and at the end of the experimental period and following
measurements were made:
- Egg weight, egg shell with the shell membrane taken as whole and egg
yolk were measured with electronic scales OHAUS – 2000 within 0.01g.
- The egg white weight was determined for greater precision in the following
way: the sum of the shell weight and the yolk weight was deducted from the value
of the egg weight.
- Form index was calculated by the formula: i=d/Dx100, where d is the small
egg diameter and D – the big egg diameter.
- Haugh unit was calculated by the formula: HU=100lg (h + 7.17 – 1.7W
0.37
) using his method (1937), where h is the height of the thick glair (in mm); W –
the egg weight.
-The shell thickness (in mm) without the shell membrane was measured by a
micrometer Amer 25EE.

Investigation of the effect ...
261
- The color of the yolk was measured visually (according to the 15 Roche
Color Fan having 15 degrees scale)
One hundred and twenty eggs from each group taken at the beginning (II
weeks) in the middle (VI weeks) and at the end (XII week) of the experimental
period were incubated by 37.7-37.8
o
C and 60% relative humidity. Egg fertility was
established on the 7
th
day of the embryonic development by ovoscoping.
The established date were statistically processed using Soft Ware product
Excel 7f .
Results and Discussion
The data about average value of laying intensity and laying capacity is pointed
in Table1. Figure1 shows the dynamics of laying intensity in Guinea fowls
throughout the experiment. The treated group had higher overall laying intensity
(P<0.05) and higher average value of laying capacity across the experimental
period. The obtained results are in agreement with the data of other authors
(Surdjiiska et al., 2005), who observed a tendency to increase the laying intensity
(P>0.05) in hens given Tribulus terrestris extract once daily with the diet in a dose
10mg/kg body weight for 20 days. At 7
th
and 8
th
weeks the experimental birds had
lower laying intensity than in control group. Grigorova (2008) reported similar
data in hens, receiving the same dose Tribulus extract with the diet for 11 weeks.
The lower laying intensity in the experimental group at 7
th
and 8
th
weeks relative to
control group could be due to physiological fatigue of the ovaries caused by the
supplemental Tribulus terrestris.
Table 1. Laying capacity and laying intensity in control and experimental groups (
x
±SE)
Control group Experimental group
Period
Laying
capacity egg
number/hen
Laying intensity
(%)
Laying capacity
egg
number/hen
Laying intensity
%
Adaptations
period
35.37 29.71 36.05 30.28
Experimental
period
55.67 66.17±2.55 67.33*** 71.10±2.65*
Significant: *** - P<0.001; ** - P<0.01; * - P< 0.05

M. Nikolova et al.
262
Laying Intensity, %
0,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
80,00
90,00
100,00
123456789101112
weeks
laying int.,
%
exper.
gr.
contr.
gr.
Figure 1. Laying intensity of Guinea fowls from control and experimental groups, %
Eggs morphological characteristics of the both groups are presented in Table
2 and in Table 3. The egg weight in the experimental group was higher (P<0.001)
throughout the whole trial than in control group. The treated group had higher yolk
weight at the middle (P<0.01) and at the end (P<0.001) of the trial. There are no
significant difference in the data about the egg white weight and yolk color
between the controls end the experimental groups. At the end of the trial was
observed the higher value of HU (P<0.05) in experimental birds, than in control
group. At the end of experimental period was found the increase of shell weight
(P< 0.001) and thickness (P<0.001) in treated birds in relation to the control group.
Probably the increased values of the above parameters are due to the effect of the
main improvement of the ovary activity and overall stimulation of vitality and
metabolism (Tomova, 1987).
The egg fertility and the weight of reproductive organs of the birds from
the both groups are pointed in Table 3. The very fact that the experimental birds
had 7.1% higher percent of fertile eggs, suggests that Tribulus extract had a
positive effect, but its share on male and female birds is not quite clear yet. Our
preliminary data indicating higher testes weight in experimental Guinea fowl cocks
suppose that the effect of Tribulus terrestris is more pronounced in cocks. This fact
is consistent with the finding that fertility established inheritance is transmited
through the father (Pimenov et al., 1983). An improvement off egg fertility in hens
receiving 10 mg/kg body weight Tribulus terrestris established of other authors
(Kashamov, 2008; Surdjiiska et al., 2005) too.

Investigation of the effect ...
263
Table 2. Egg weight and form index in control and experimental groups (
x
±SE)
Control group Experimental group
Items
Start of exp. Midle of
exp.
End of exp. Start of
exp.
Midle of
exp.
End of exp.
Egg weight, g 40.28±0.22 a
1
40.92± 0.22 a
2
39.61± 0.20 a
3
40.72±0.25a
1
43.80± 0.22 a
2
42.37± 0.33 a
3
Form index 74.44±0.29
с
1
А
1
В
1
75.57± 0.20
a
4
В
1
В
2
76.37± 0.20
с
2
А
1
В
2
73.72±0.25
с
1
А
2
73.95±0.33
a
4
А
3
75.57± 0.27
с
2
А
2
А
3
Significant: a, A - P<0.001; b, B - P<0.01; c, C - P<0.05
Table 3. Egg white weight, Haugh Units, yolk weight, yolk color (Roche), Egg shell weight
and egg shell thickness in control group and experimental group (
x
±SE)
Control group Experimental group
Items
Start of
exp.
Midle of
exp.
End of exp. Start of
exp.
Midle of
exp.
End of exp.
Egg white
weight, g
20.17±
0.35
21.05± 0.51 20.42±
0.42
20.24±
0.27b
1
22.62±
0.80b
1
c
3
20.44± 0.46c
3
Egg white, % 51.00±
0.67
51.48±
0 .89
51.03±
0.29b
2
51.05± 0.53 51.91±
0.84В
3
48.91± 0.56b
2
В
3
Haugh Units 94.61±
0.64
93.82± 0.41 94.20±
0.53c
4
95.18± 0.30 94.79± 0.44 95.62± 0.41c
4
Yolk weight, g 11.96±
0.14
12.00± 0.22 11.85±
0.43b
3
12.11±
0.14А
4
В
4
12.70± 0.21
В
4
13.19± 0.23
b
3
А
4
Yolk, % 29.30±
0.35
29.80± 0.41 29.83±
0.38 b
4
29.69± 0.34 28.94±
0.73В
5
31.61±
0.50b
4
В
5
Yolk color
Roche
12.04±
0.22
А
5
А
6
10.80± 0.27
А
5
С
1
9.88± 0.30
А
6
С
1
12.06± 0.19
А
7
А
8
10.91± 0.22
А
7
В
6
9.76± 0.25
В
6
А
8
Egg shell
weight, g
8.11± 0.15 7.83± 0.17 7.61±
0.18 a
5
8.17± 0.12 8.18±
0.12 А
9
8.84± 0.16a
5
А
9
Egg shell, % 19.62±
0.31
18.66± 0.37 19.10±
0.45
19.02± 0.25 19.15± 0.23 19.40± 0.32
Egg shell
thickness
0.54±
0.007
0.52± 0.007a
6
0.54±
0.007a
7
0.54± 0.007 0.54± 0.008a
6
0.56± 0.006 a
7
Significant: a, A - *** - P<0.001; b, B - ** P<0.01; c, C - * P<0.05

M. Nikolova et al.
264
Table 4. Egg fertility and weight of reproductive organs (
x
±SE) in control and experimental
groups
Control group Experimental group
Period
Eggs, n Fertility, % Eggs, n Fertility, %
Beginning of the trial 120 84.47 120 92.86*
Middle of the trial 120 89.74 120 97.37
End of the trial 120 89.19 120 95.16
Total 360 88.04 360 95.14***
Weight of reproductive organs
Control group Experimental group
Ovary n=6 Right testis
n=3
Left testis
n=3
Ovary
n=6
Right testis
n=3
Left testis
n=3
7.57±0.48 1.30±0.31 1.73±0.23* 7.73±0.95 1.58±0.12 2.67±0.1*
Significant: *** - P<0.001; ** - P<0.01; * - P< 0.05
Conclusion
The addition of 10 mg/kg body weight Vemoherb-T (dry extract of
Tribulus terrestris) to the forage of breeder Guinea fowls increased significantly
(P<0.05) laying intensity, egg weight (P<0.001), yolk weight (P<0.01), shell
weight (P<0.001) shell thickness (P< 0.001), Hu (P<0.05).
No significant differences were found about glair weight and yolk color
between the control and experimental groups. The tested product improved the egg
fertility.
It was found the higher testes weight in experimental Guinea fowl cocks.

Investigation of the effect ...
265
Istraživanje uticaja ekstrakta Tribulus terrestris na neke
reproduktivne osobine morki
M.Nikolova, S.Grigorova, D.Abadjieva, D.Penkov
Rezime
Uticaj bugarskog proizvoda Vemoherb-T (suvi ekstrakt biljke Tribulus
terrestris) na neke reproduktivne osobine morki (Numida meleagris) je bio
predmet istraživanja. Ogled je izveden na 30 biserno-sivih morki u uzrastu od 32
nedelje, koje su bile podeljene na dve grupe, 12 ženki i 3 mužjaka u svakoj grupi.
Ptice iz obe grupe su dobijale obrok koji se sastojao od iste smeše.
Eksperimentalna grupa je dobijala proizvod koji se testirao, jednom dnevno u dozi
od 10 mg/kg telesne mase u trajanju od 12 nedelja. Intenzitet nosivosti, morfologija
jaja i plodnost, težina testisa i jajnika su kontrolisani. Utvrđeno je da je nosivost
bila veća (P<0.05), kao i težina jaja (P<0.001), težina žumanceta (P<0.01), težina
levih testisa (P<0.05) i plodnost kod grla iz eksperimentalne grupe. Nije utvrđena
signifikantna razlika kod vrednosti težine belanceta i boji žumanceta između dve
grupe.
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Received 24 March 2010; accepted for publication 20 May 2010