Exterminating Effect of Wood Vinegar to Red Mites and

its Safety to Chickens

Kohsyo Yamauchi1, Noboru Manabe

2, Yoshiki Matsumoto

3and Koh-en Yamauchi

3

1Miyazaki Midori Pharms. Inc., 945 Hieda, Akae, Miyazaki-city, 880-0912, Japan

2Animal Resource Center, Graduate School of Agriculture and Life Sciences, The University of Tokyo,

Ago 3145, Kasama, Ibaraki, 319-0206, Japan3Laboratory of Animal Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan

Effects of wood vinegar (WV) on red mites, safety test for chicks, and egg production performance were

examined. In the counting of red mite numbers at cage knots using RGB color range of red mites by the image

analyzer, the red mite were decreased after spraying (P＜0.01). In a WV safety test for 8-day-old chicks, one ml of

water, original WV, or WV diluted 500 and 1,000 times were tube-fed twice daily for 6 days. The rate of body weight

gain was decreased in original WV group than that in the control (P＜0.05), but it was not different in both WV

dilution groups compared with that in the water-only group. In spraying one ml WV to the hen’s face twice per day

for 8 days, the egg production performances of WV group did not changed so much compared with those of the

control and initial day. These results suggest that the WV did not reduced production performance.

From these results, WV could exterminate red mites, and did not reduce egg production, suggesting that WV is a

useful natural substance to exterminate red mites without harmful effect.

Key words: egg production, extermination, laying hen, mortality, red mite, wood vinegar

J. Poult. Sci., 51: 327-332, 2014

Introduction

Red mites (Dermanyssus gallinae, poultry red mite,

chicken mite) are the most important epidemiological and

economical problem for the poultry industry worldwide.

This red mite is a blood-sucking pest that causes losses in

poultry production because of irritation and anemia. Red

mite-infected hens self-groom and scratch their heads during

the day and night (Kilpinen et al., 2005). Infected hens also

show reduced weight gain (Chauve, 1988; Kilpinen et al.,

2005), egg production, and egg quality (Chauve, 1988;

Cencek, 2003), as well as anemia and death (Kilpinen et al.,

2005). In some case, red mites cause staining of the egg

shell surface (Cencek, 2003). Therefore, poultry farmers

must clean empty houses between flock cycles with 70℃

high-pressure steam to control the red mites. Furthermore, a

variety of chemical medicines have been also used. How-

ever, continued use of chemicals has induced the develop-

ment of drug-resistant red mites. Furthermore, chemical use

results in environmental contamination. Therefore, alterna-

tives are being developed to control red mites and to reduce

environmental pollution through the use of natural resources.

Traps impregnated with neem oil originating from the

Azadirachta indica tree significantly reduce red mite field

populations (Lundh et al., 2005), and pure garlic juice

quickly kills these mites (Maurer et al., 2009). These reports

suggest that plant-derived compounds may be useful to

control red mites.

A wood vinegar (WV) solution was prepared after cooling

smoke during charcoal preparation from the bark of broad-

leaf trees. As WV includes phenols (Matsui et al., 1998),

and inhibits the growth of Salmonella Enteritidis but stimu-

lates the growth of Enterococcus faecium (Watarai and Tana,

2005), we conducted a preliminary test to determine whether

WV could kill red mites, resulting in that the red mites

disappeared from the chicken cages after spraying 500 di-

lution WV.

Therefore, purpose of the present work was to establish

whether the WV can exterminate red mites without lowering

egg production performance by spraying WV on red mites

and chickens.

Materials and Methods

Effects of Spraying WV on Red Mites in Cage Knots

Eight points of cage in a hen laying house knots were

Received: September 17, 2013, Accepted: November 6, 2013

Released Online Advance Publication: December 25, 2013

Correspondence: Y. Matsumoto, Laboratory of Animal Science, Faculty of

Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan.

(E-mail: myoshiki@ag.kagawa-u.ac.jp)

http:// www.jstage.jst.go.jp / browse / jpsa

doi:10.2141/ jpsa.0130170

Copyright Ⓒ 2014, Japan Poultry Science Association.

randomly selected as observation points (treatment: four

points were sprayed with 1ml of 500 dilution WV, control:

others were not spraying). To analyze the exterminating

effect of WV to red mites, each point was taken a photograph

with a digital camera. The numbers of red mites appeared on

the screen were estimated by the color range of photograph

using the image analyzer (Win Roof, MITANI

CORPORATION, Tokyo, Japan). Color range was meas-

ured using red, green and blue color code (RGB) (range is 0

to 255), and expressed by dot numbers (one dot was 0.02

mm2). In the case of red mite, 82 to 99 color range of red,

47 to 67 color range of green, and 69 to 82 color range of

blue (total 5292 RGB color range) were identified as a color

of red mites, and mean size of red mites was 36 dots (0.72

mm2). After 24 h spraying to treatment points, the eight

points of cage knots were again taken a photograph, and

RGB color ranges were compared between control and

treatment groups.

WV Safety Test on Chicks

A safety test was performed according to the “chick

growth test” on the basis of the safety assessment standard

for the feed and evaluation procedure (the 597th

20 con-

sumption life article) from the Ministry of Agriculture,

Forestry and Fisheries consumption safety chief on May 18,

2008. Twenty-four Sanuki Cochin male chicks (8 days old)

were tube-fed water, original WV, or WV diluted 500 and

1,000 times with water. One ml of each solution was given

twice daily in the morning and evening for 6 days. Starter

mash diet for layers (CP, 21.0%; ME, 3,000 kcal/kg) was fed

ad libitum, and initial and final body weights were measured

to calculate body weight gain rate (body weight gain/initial

body weight). Lethal Dose, 50% (LD50) value was calcu-

lated using the formulas:

(A/6＋B/6)÷2＝C,

2 g×6 days＝12÷C

where,

A＝initial body weight of six birds

B＝final body weight of live birds

C＝mean body weight

Effects of Spraying WV on Egg Production Performance in

Laying Hens

Sixteen hens (Sonia strain, 24-week-old) with similar egg

production performance were selected. They were continu-

ously fed the same diets (CP, 17%; ME, 11.93MJ/kg), and

divided into 2 groups: control and WV spraying groups. One

ml of original WV solution was sprayed on the hen’s face

twice per day for 8 days in WV group (control was only

feeding conventional basal diet without spraying). Feed

intake, hen-day egg production, egg mass weight, egg

weight, feed efficiency, shell-breaking strength, shell

thickness, shell ratio, albumin ratio, yolk ratio, yolk color,

and Haugh units before spraying WV were compared with

those after WV spraying to hens.

Statistical Analysis

The numbers of red mites, body weight gain and egg

production performance were analyzed by one-way analysis

of variance with the Statistical Package for the Social Sci-

ences software version 10.0 for Windows (SPSS, Inc.,

Chicago, IL, USA). In the RGB color range and production

performance, significant differences between groups were

analyzed using independent samples t-test. Differences were

considered significant at P＜0.05. In body weight gain, dif-

ference among treatment groups was assessed by Duncan’s

test and were considered significant at P＜0.05. The pro-

duction performance and numbers of red mites between

before and after spraying were assessed by a paired samples

t-test in SPSS at P＜0.05.

All experiments and collection protocols in the present

study were managed in accordance with the guidelines and

rules for animal experiments, Kagawa University, Japan.

Results

Effects of Spraying WV on Red Mites in Cage Knots

Fig. 1 shows example pictures of cage knots during

experiment. Many red mites appeared on cage surfaces from

the inner part of cage knots, and many red mite eggs were

destroyed at points 1 and 2, but not 3 after spraying the WV.

Table 1 shows the RGB color ranges in cage knots of two

groups were 29±7 and 59±14, respectively (Table 1; P＝

0.329). Then, one group showing value of 29±7 was not

sprayed WV (control); the group of 59±14 was sprayed WV

(treatment). The RGB color ranges on the next day was 40±

4 in the control group, but 10±2 in the treatment group,

resulting in that the RGB color ranges of treatment group

decreased than those of the control (P＜0.01). When these

values of 29 and 40 were calculated as an increased ratio (%),

it was ＋37±29 in the control group. This means that the

numbers of red mites showed 37% increase in a day (P＜

0.01). In the case of the treatment group, the increased ratio

was −91±5; the numbers of red mites showed 91%

decrease in a day after spraying WV than those before

spraying it (P＜0.01).

WV Chick Safety Test

Two birds in the original WV group were dead on days 4

or 6 after starting the safety test. The rate of body weight

gain was significantly lower in the original WV group (P＜

0.05) but was not different in the 500 and 1,000 dilution WV

groups compared with that in the water-only group (Table 2).

Although there was no systematic attempt to quantify other

measurement, no differences were observed in behavior,

feather color, or feces among the groups. Calculated LD50 of

the original WV group for chicks was 126,316mg/kg.

Effects of Spraying WV on Egg Production Performance in

Laying Hens

Table 3 shows the egg production performance of the

control (no spraying) and WV group on initial (upper) and

final (lower) days for 8-day-raising. Egg production per-

formance was not different between groups both on initial

and final days. Compared with values of production per-

formance on the initial day, yolk color value was higher on

the final day (P＜0.05). In the WV group, the albumin ratio

(P＜0.05) was lower, but egg mass weight (P＜0.05) and

shell ratio (P＜0.01) were higher than those of the initial day.

Journal of Poultry Science, 51 (3)328

Discussion

The current egg layer breeding method has changed from a

floor feeding system to a large-scale cage feeding system

with high bird densities. This change in feeding system has

promoted development of red mites, and stressed birds,

resulting in poor production performance. Red mites live in

the knots of cages, on the egg conveyor belt, or hidden in

cracks and crevices where they lay eggs during the day.

Because the feeding‒oviposition cycle of the red mite repeats

about every third day (Kirkwood, 1963; Desch, 1984), its

life cycle can be completed within 1 week, and large popu-

lations can be rapidly established in poultry houses (Chirico

et al., 2003). Therefore, poultry industry needs an effective

insecticide with sustained but not harmful effect.

A variety of chemical medicines such as organo phos-

phorous compounds (dichlorvos, malathion, metriphonate),

carbamates (propoxur), and synthetic pyrethroids (cyfluthrin

and pyrethrin I and II) were used in poultry house (Höglund

et al., 1995; Chirico and Tauson, 2002; Murano, 2007;

Yamauchi et al.: Exterminating Effect of Wood Vinegar 329

＋37±29

Treatment (4)

After 40±4

Before 29±7

Table 1. Effect of spraying wood vinegar (WV) on red, green and blue (RGB) color

range of cage knots

(/cm2)

RGB color range

Control (4)

Values are means±SEM of the number of observed points in parentheses.

−91±5

0 .005

0 .329

p-value

59±14

Increased ratio (%)

10±2

Fig. 1. Red mites on cage knots before and after wood vinegar (WV)

spraying. 1 & 2: WV spraying, 3: no WV spraying.

Murano et al., 2008). However, these reports show that

many chemicals were difficult to exterminate red mites per-

fectly in a short term. The result of spraying to cage knots

revealed 91% of red mites was disappeared by the present

WV solution after 24 h spraying (Table 1). Although there

was no systematic attempt to quantify other measurement,

many red mite eggs were destroyed and their eggs could not

be found at WV spraying points 1 and 2 (Fig. 1). Col-

lectively, these results indicated that WV had strong in-

secticidal effect, but not evasion effect on the red mites in a

short term.

As for the chemical medicines as mentioned above, the

toxicity becomes the problem (Kim et al., 2007). Actually,

when hens with red mites had soaked and their cages were

Journal of Poultry Science, 51 (3)330

Mortality

82 .5±4 .2a

85 .8±4 .4a

56 .3±10 .1b

Table 2. Effect of oral administration of wood vinegar

(WV) solution on body weight gain and mortality in

chicks (mean±SEM, n＝6)

1,000 WV

77 .8±2 .9a

Water

Body weight gain rateGroup

Means with different letters are significantly different at p＜0.05.

500 WV: wood vinegar diluted with water at 500 times, 1,000 WV:

wood vinegar diluted with water at 1,000 times.

500 WV

0/6 (0%)

0/6 (0%)

2/6 (33%)WV

0/6 (0%)

Yolk color

WV

12 .5±0 .3

Table 3. Effect of spraying wood vinegar (WV) on egg pro-

duction performance in laying hens (mean±SEM, n＝4)

75 .1±4 .7

Feed intake

Haugh unit

Items

Means with different superscripts differ from upper and lower significantly

(p＜0.05).

Albumin ratio (%)

59 .4±0 .4b

27 .7±0 .4Yolk ratio (%)

29 .6±0 .3

98 .5

12 .0±00

81 .7±1 .2

0 .37±0 .15Shell thickness

0 .41±0 .16(mm)

105 .3

10 .1±0 .3a

Shell ratio (%)

11 .0±0 .4b

(g/hen/day)

62 .2±0 .7a

65 .5±1 .3

0 .65Feed efficiency

0 .62

2 .88±0 .22Shell-breaking

2 .68±0 .58strength (kg/cm2)

Control

75 .0±9 .6Hen-day egg

82 .0±4 .0production (%)

36 .3±3 .8a

Egg mass weight

54 .5±2 .2b

(g/hen/day)

64 .2±1 .8Egg weight

50 .5±2 .4

46 .0±3 .2

78 .5±4 .0

86 .0±4 .0

104 .8

90 .4

2 .68±0 .45

0 .61

0 .69

64 .0±1 .5

62 .4±2 .4

10 .3±0 .1

9 .9±0 .5

0 .39±0 .18

0 .36±0 .21

2 .78±0 .11

13 .0±0 .0(b)

11 .8±0 .3(a)

27 .9±1 .2

27 .2±0 .3

61 .8±1 .1

62 .9±0 .8

─

─

P-value

75 .8±5 .2

80 .8±3 .6

0 .505

0 .580

0 .269

0 .100

0 .554

0 .129

0 .562

0 .872

0 .703

─

─

0 .109

0 .500

0 .177

0 .672

0 .437

0 .310

0 .370

0 .182

0 .391

0 .246

0 .476

sprayed every day for two weeks using the custom method

(soak; 1,000 times diluted pyrethroid insecticide solution,

spraying: a mixed solution of liquid paraffin and pyrethroid

insecticide), we found that the treatment could not control the

red mites while egg production rate gradually decreased to

30% and birds began to die (unpublished data). According to

Poisonous and Deleterious Substances Control Law, a poison

has an LD50 ＜50mg/kg, and deleterious compound has an

LD50 ＜300mg/kg. In rats, the LD50 was 5,000mg/kg

(Watanabe et al., 2008). In this study, the present higher

value of LD50 of 126,316mg/kg than that of rat was safe for

chicks, suggesting that diluted WV has no harmful effect on

chickens. Moreover, WV spraying the hen’s face with WV

may not have induced stress because their egg production

performances did not changed (Table 3). Therefore, it is also

possible that WV can improve poultry production. However,

the albumin ratio was lower than those of the initial day.

Further work is needed to investigate the effect of WV

spraying on egg quality.

Although it is considered that they suck blood from hens at

night and leave before daybreak (Arends, 1991), they para-

sitize and propagate on the chickens day and night without

leaving the chickens before daybreak (Nakamae et al., 1997).

Thus, daytime spraying could be useful for anthelmintic of

red mites. In fact, we observed in spraying a 200-ml solution

of 500 times diluted WV with tap water to red mites ac-

cumulating on hen’s feathers around the cloaca (Left in Fig.

2), the WV could exterminate these red mites on day 4 after

spraying (Right in Fig. 2).

Another problem for chemical medicines is the develop-

ment of drug resistance. Repeated long-term control of red

mites with the chemicals induces the development of heri-

table resistance in the mites (Zeman, 1987). It is likely that

the WV might not induce such a resistance in the mites,

because the WV is natural substance. In the report using

natural substances, cardboard traps containing 20% neem oil

from the tree Azadirachta indica induced a 92% reduction of

red mites after placing traps at the mites’ aggregation sites

for four weeks (Lundh et al., 2005). These reports imply

that natural substance such plant can also control the red

mites without drug resistance.

In conclusion, WV could exterminate red mites and spray-

ing WV on hens did not reduce egg production, suggesting

that WV is a useful natural substance to control red mites

without lowering egg production performance.

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Journal of Poultry Science, 51 (3)332