Effect of Certain Evaluated Plant Crude Extracts on the Productivity of Silkworm (Bombyx mori L.)

INTRODUCTION
The improvement and increasing the nutrition values of mulberry leaves by
using various food additives were studied by many investigators. Kumaraj et al.
(1972) reported that the important factor influencing the growth and production of
silkworm is the nutritional factor.
Numerous of food additives materials were examined as supplementary nutrients
by (Ito and Tanaka, 1962; Majumeder and Medder, 1975; El-Karaksy et al., 1983;
Moustafa and El-Karaksy, 1988; El-Karaksy and Idriss, 1990; El-Sayed and
Mesbah 1992, a & b; El-Sayed, et al., 1996; Ashour, 1997; El-Sayed et al., 1997 &
1998).
On the light of abovementioned literature, the present work was initiated for
determining the effect of supplementing mulberry leaves with three plant crude
extracts (Chamomile, Fennel and Thyme) at certain concentrations on the silkworm
(Bombyx mori) as a trial for improving and increasing of silk production and female
productivity.
MATERIALS AND METHODS
The newly hatched larvae of the eggs of the mulberry silkworm Bombyx mori L.
(hybrid Giza A) were reared in the laboratory according to the standard rearing
technique as advocated by Krishnaswami (1973) under the hygrothermic
conditions of 25 ± 2°C and 75 ± 5% R.H. The larvae were raised on fresh clean
mulberry leaves until 4th instar. Only the last larval instar was used in the
experiment.
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Substances used:
Certain types of herbs were chosen as supplementary nutrients for the silkworm
Bombyx mori L. and these substances were: Chamomile (Matricaria chamomilla),
Fennel (Foeniculum vulgare) and Thyme (Thymus Vulgaris).
Fresh aqueous crude plant extracts were daily prepared by blending 350 grams of
each herb used with two liters of tap water, soaked for about 24 hrs. at room
temperature, evaporated by heating up to one liter as a final volume and filtered to
give a stock solution of 35% (w/v). The tested concentrations of 3, 5 and 10% were
prepared from the stock solution of each crude extract using tap water. The natural
and chemical components of these materials are presented in Table 1.
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Table 1: The composition of the natural and chemical components of
extracted plant used substances*
Seed extract
components
Chamomile
Every 237g of flowers
contains
Fennel
Every 100g of seeds
contains
Thyme
Every 100g of seeds
contains
Energy 5.736 kcal 101 kcal 345 kcal
Carbohydrates 0.5 g 24.45 g 52.29 g
Protein -- 5.56 g 15.80 g
Total Fat -- 1.68 g 14.87 g
Cholesterol -- -- --
Dietary Fiber -- 14.0 g 39.8 g
Vitamins
Niacin -- 1.824 mg 6.050 mg
Pyridoxine -- 0.348 mg 0.470 mg
Riboflavin -- 0.471 mg 0.353 mg
Thiamin -- 0.48 mg 0.408 mg
Vitamin A 47.4 IU 4751 IU 135 IU
Vitamin C -- 160.1 mg 21 mg
Electrolytes
Sodium 2.4 mg 9 mg 88 mg
Potassium 21.3 mg 609 mg 1694 mg
Minerals
Calcium 4.7 mg 405 mg 1196 mg
Copper -- 1.067 mg
Iron 0.2 mg 17.45 mg 18.54 mg
Magnesium 2.4 mg 160 mg 385 mg
Manganese 0.1 mg 1.719 mg 6.533 mg
Phosphorus -- 487 mg
Zinc 0.1 mg 1.81 mg 3.70 mg
*USDA. U.S. Department of Agriculture 1400 Independence Ave., S.W.
Washington, DC 20250.
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Therefore, the initiated experiment included nine treatments and control. Each
treatment was replicated three times. Each of which contained 50 fifth instar larvae.
The mulberry leaves were dipped in the prepared dilutions of each prepared plant
crude extract. The treated leaves were introduced to the treated larvae after being
dried. The larvae of the control treatment were provided with untreated leaves.
Estimation of the studied parameters:
The mature 5th instar larvae, pupae, fresh cocoons and cocoon shells were
weighed. Moreover, prior to spinning cocoons, a sample of five mature
experimented larvae as well as control was dissected and the silk glands were
drawn and weigh. For estimating the female fecundity in each conducted treatment
and control, five couples of mated moths were randomizly elected; each couple
was kept in perforated paper bag till end of egg deposition. Number of eggs laid
per female moth were counted and recorded. Increase percentage over control
was recorded. Data were statistically analyzed on the basis of “ F ” test and the
least significant difference test (L.S.D.) at 0.05 level (Sendecor, 1956).
RESULTS AND DISCUSSION
Effect of the tested materials on the biological parameters of the silkworm
(Bombyx mori L.)
The results presented in Table 2 show that the mean weights of full grown larvae
were significantly different. The use of Thyme at the concentration rate of 3 and
5%, Chamomile at 3% and Fennel at 5% gave the heaviest level weights of 3.117,
3.242, 3.08 and 3.017 g, respectively, and these weights were more than the lower
mean weight of control larvae (2.626 g). The lightest weight of larvae was obtained
after feeding on the treated mulberry leaves with Chamomile, Fennel and Thyme at
the concentration of 10%.
Statistical analysis of data also proved that both treatments of Thyme and Fennel
at 3 and 5% and Chamomile at 3% gave a more or less heavier pupal weights,
which decreased in all performed treatments at 10%, but still significantly higher
than that of the untreated control larvae (0.873 g), except Chamomile (10%) which
rather decreased by -0.572% than that of the control.
The measured increased fresh weights of silk glands of the treated mature larvae
indicated insignificant differences between the estimated weights of the most made
treatments, while Thyme at 5% gave the lightest weight of (0.583 g) with 17.303%
increase over control (0.497 g)(Table 2).
Herein, these abovementioned results are in accordance with those reported by El-
Sayed (1989 and 1994); Govindan et al. (1988); El-Karaksy and Idriss (1990);
Muniandy et al. (1995); Manoharan (1997); Mahmoud and Yehia (2007); Benţea et
al. (2011) and Mahmoud et al. (2012) who found that the detected parameters of
fitness component of Philosamia ricini Boisd or/and Bombyx mori L. larvae were
significantly affected by the evaluated food additives in their works.
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Effect of tested materials on silk and egg production
Results in Table 3 elucidate the effect of each of the tested materials on silk and
egg production. The treatment of Thyme at 5% and Chamomile at 3% gave the
heaviest fresh cocoon weight of 1.323 and 1.294 g, in respect, with an increase of
21.487 and 18.824%, respectively over control. The lightest weight of (1.102 g)
was recorded for the treatment of Chamomile at 10% with an increase of 1.193%
over control.
In comparison to different initiated treatments and control, statistical analysis of
data proved that Thyme at all its tested concentrations were greatly effective on the
detected weights of cocoon shell and that might be due to its higher content of
protein and total fats. The corresponding weights of cocoon shells increased by
about 10.648, 18.981 and 21.296 %, respectively more than the control. The
treatments of Fennel at 10% and Chamomile at 5% were less effective; indicating
lower weights than those inspected in the other running treatments, but still
significantly heavier than the control.
Moreover, the revealed effect of tested materials on the female reproductivity
elucidated that the resulted female moths from the treatments of Thyme 5% and
Chamomile 3% laid an average number of 406.2 or/and 405.0 eggs/female moth,
respectively as against 333.8 eggs/female laid by control insects, since the rate of
produced eggs had been increased by about 21.689 and 21.33 more than the
control (Table, 3).
These observations suggest that these materials that enhance egg production
would be beneficial to sericulturists, since such materials increase both silk
productivity and eggs deposition of these characters meet the demand of
sericulturists.
In agreement with our obtained results many authors have reported that the tested
nutrients and food additives; besides influencing the overall growth, enhanced
fecundity of silkworms (Govindan et al, 1988; El-Karaksy and Idriss, 1990; Hosney
et al., 1991; El-Sayed, 1994; Manoharan, 1997; Yehia, 1998; Mahmoud and Yehia,
2007 and Mahmoud et al., 2012).
Generally, it could be concluded that the results of the present study support the
fact that identifying the optimum concentration of the chosen nutrient for a chosen
insect is an important aspect in supplementation studies for better growth as the
tested plant crude extracts, contain many biochemical components such as vitamin
A, thiamin, riboflavin, fats and protein. Though, in the present study the optimum
concentration for elevating the growth of Bombyx mori L. larvae as well as their
productivity was found to be 3% of Chamomile and 5% of either Fennel or Thyme.
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Table 2: Effect of the tested materials at different concentrations on the
measured weights of larvae, pupae and silk glands
Treatments
Wt. of
larva (g) A*
Wt. of
pupa (g) A
Wt. of silk
gland (g)
B*
increase percentage over control (%)
Wt. of
larva
Wt. of
pupa
Wt. of silk
gland
#
C3%
3.08 bc**
±0.179
1.054 a
±0.110
0.638 a
±0.078
17.557
20.733
28.37
C5%
2.97 cd
±0.149
0.932 cd
±0.121
0.609 a
±0.112
13.358
6.758
22.535
C10%
2.847 de
±0.119
0.868 d
±0.134
0.610 a
±0.108
8.664
-0.572
22.736
F3%
2.984 c
±0.147
1.006 abc
±0.119
0.604 ab
±0.036
13.893
15.234
21.529
F5%
3.017 bc
±0.161
1.023 abc
±0.114
0.608 a
±0.084
15.152
17.182
22.334
F10%
2.759 e
±0.103
0.942 bcd
±0.092
0.615 a
±0.071
5.305
7.903
23.742
T3%
3.117 ab
±0.125
1.026 abc
±0.143
0.661 a
±0.079
18.969
17.525
32.997
T5%
3.242 a
±0.168
1.066 a
±0.136
0.583 ab
±0.097
23.74
22.107
17.303
T10%
2.829 e
±0.099
0.973 abcd
±0.129
0.611 a
±0.087
7.73
11.454
22.937
Control
2.626 f
±0.122
0.873 d
±0.140
0.497 b
±0.037
--
--
--
L.S.D.
17.129
3.208
1.331
# C= Chamomile F= Fennel T=Thyme
* Each value represents the mean ± S.D. of A=10 B=5 records.
** No significant differences among the means followed with the same letter(s).
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Table 3: Effect of the tested materials on silk and egg production
Treatments
Wt. of
fresh
cocoon (g)
A*
Wt. of
cocoon
shell (g) A
No. of dep.
Eggs
B*
increase percentage over control (%)
Wt. of
fresh
cocoon
Wt. of
cocoon
shell
No. of dep.
Eggs
#
C3%
1.294 a**
±0.122
0.240 abc
±0.027
405 a
±20.688
18.824
11.111
21.33
C5%
1.153 bc
±0.134
0.221 bc
±0.022
407.4 a
±18.568
5.876
2.314
19.772
C10%
1.102 c
±0.138
0.234 abc
±0.019
397.4 b
±11.523
1.193
8.333
19.053
F3%
1.248 ab
±0.144
0.242 abc
±0.034
395.2 b
±20.364
14.6
12.037
18.394
F5%
1.271 ab
±0.131
0.247 ab
±0.041
388.8 bcd
±11.627
16.712
14.351
16.476
F10%
1.170 bc
±0.102
0.227 bc
±0.046
392 bc
±6.782
7.438
5.092
17.435
T3%
1.266 ab
±0.168
0.239 abc
±0.038
380.8 d
±16.422
16.253
10.648
14.08
T5%
1.323 a
±0.157
0.257 a
±0.031
383.6 c
±13.685
21.487
18.981
21.689
T10%
1.235 ab
±0.128
0.262 a
±0.025
362.8 e
±15.610
13.406
21.296
8.687
Control
1.089 c
±0.147
0.216 c
±0.024
333.8 f
±18.886
--
--
--
L.S.D.
3.437
2.086
9.456
# C= Chamomile F= Fennel T=Thyme
* Each value represents the mean ± S.D. of A=10 B=5 records.
** No significant differences among the means followed with the same letter(s).