EFFECT OF STINGING NETTLE FEEDING ON PRODUCTIVITY AND IMMUNE
STATUS IN LAYING HENS
N. Poudel1 and D. R. Khanal2
1IAAS, TU, Rampur, Chitwan, Nepal
2Animal Health Research Division, Nepal Agricultural Research Council
Corresponding author's e-mail: firstname.lastname@example.org
The effect of feeding stinging nettle on productivity and immune status in laying hens
of 52 weeks of age was investigated in a 10 weeks long trial at Animal Health Research
Division, Khumaltar, Nepal. A total of 80 laying hens and eight cocks of Black Australorp
breed were divided into four groups: T1 (Induced molting by feed restriction), T2 (6% nettle
supplementation of dry matter twice weekly), T3 (12% nettle supplementation once weekly)
and C (Control);each group consisting of 20 laying hens and two cocks. Parameters like egg
productivity, egg quality and immune status were recorded. Egg quality in terms of eggshell
thickness and egg albumin height of seven eggs from each group were measured by using
Spherometer. On the 4th week of the trial, ten eggs from each group were collected and stored
at room temperature to simulate rural areas without cold storage for 5 weeks to observe the
internal quality of eggs. The birds were re-vaccinated on 7th week of the trial with live B1
strain of Newcastle Disease (ND) vaccine. Blood samples were collected on the day of ND
vaccination and on 28 days post-vaccination. Differential leukocyte count (DLC) and antibody
level against ND were determined for assessing the immune status of birds. Available data
revealed that egg shell thickness and calcium content were higher in T2 (0.34 ± 0.04 mm
and 1.21%) followed by T3 (0.3 ± 0.05 mm and 1.13 %), T1 (0.28 ± 0.03 mm and 1.01%)
and C (0.27± 0.023 mm and 1.02%) while albumin height was highest for T3 (7.09 ± 1.05
mm) followed by T2 (6.59 ± 1.08 mm), C (5.72 ± 1.03 mm) and T1 (5.02 ± 0.68 mm). Data on
antibody titer and DLC were also slightly higher for T3 and T2 than T1 and C. These ndings
indicated that nettle supplementation increases the egg quality besides improving the immune
status of laying hens.
Key words: stinging nettle, immunomodulatory, laying hens, egg quality
Increasing demand of poultry products has led to unnecessary use of hormones and other
chemicals to boost the productivity and productivity of birds. The indiscriminate use of such
production boosters will result in serious effects on birds’ health; decrease production period
and alter physiological state leading to a compromised immune system. Moreover, rise in
consumers’ preference towards organic products has prompted to seek an alternative for such
production boosters. Many herbal and other plant extracts are presumed to have positive
inuence in productivity.
Nepalese Vet. J. 30: 51-58 Research Article
There is dearth of information on effect of herbal supplementation on production performance
of poultry. The rst evidence of use of nettle in birds is by Juliette (1984) whereby nettle
was used to treat worms in birds. In recent days, some researchers have documented the
immunomodulating property and improvement of blood lipid prole (Daher et al., 2006)
of aqueous and ethanol extract of nettle and many other benecial effects on experimental
animals. However, no such evidences are found in relation to productivity of birds.
Grela et al (2006) have documented that supplement of herbs or herbal extracts (nettle, oregano,
Echinacea, garlic and lemon balm) can exert a positive effect on the health and reproductive
traits of sows. Pilot research done at Agricultural Research Station, Pakhribas, Nepal had
shown that weekly feeding of 12% nettle powder to layers improved the egg laying capacity
by 35% besides keeping the bird healthy (Khanal, 2005a). Furthermore, pigs fed with cooked
nettle at 30% level had shown a signicant weight gain with a good body musculature. Nettle
fed pork was found tastier in sensory evaluation (Khanal, 2005b).
The usual practice of induced moulting for enhancing laying performance in commercial
layers has been termed inhumane and criticized by the animal welfare groups. The present
exploratory research was aimed at evaluating the effect of abundantly available stinging nettle
(Urtica dioica) feeding as an alternative to induced molting for enhancing the productivity and
the immune status of laying hens.
MATERIALS AND METHODS
Eighty Australorp layers and 8 cocks of 52 weeks age were procured from the Swine and Avian
Research Programme (SARP), Khumaltar and randomly allocated into four groups comprising
of 20 hens and 2 cocks in each group. The rst group consisted of induced moulting (T1) while
the second group (T2) received 6% nettle powder twice weekly, the third group (T3) received
12% nettle once weekly and the last group served as the control group (C). Nettle feeding was
switched between control and 12% fed group after one month but no change was done in T1
and T2 groups.
At the time of purchase, the birds were fed commercial pellet layers ration at the rate of 150
gm per bird per day, but it was decreased to 120 grams per bird after a month. Clean drinking
water was provided ad libitum after disinfection with Chlorine (Water guard). In the induced
molting group (T1), water was withdrawn for 3 days followed by feed for 10 days. However,
ad libitum drinking water was provided during feed withdrawal period. Feeding was resumed
in T1 group with 50 gram feed per bird per day with gradual increment up to normal level as
in other groups.
Assessment of egg production and quality
Eggs were collected twice a day; in the morning and in the evening. Weekly production
Poudel and Khanal
performance was recorded. The egg albumin height was measured on 7 eggs from each group.
Four eggs from each group were subjected to proximate analysis to determine egg protein,
fat and calcium levels. The egg shell thickness was measured using gauge Spherometer. For
assessing egg quality, ten eggs from each group were collected and stored at ambient temperature
for ve weeks. After ve weeks of storage, the eggs were broken and interior was observed.
Assessment of Immune Status
Blood samples of ve birds from each group were collected randomly on the day of vaccination
against ND. Using 23 gauge needle, 2 ml of blood was drawn from the jugular vein. The
blood samples were again collected on 28 days post-vaccination with ND oral vaccine (La
Sota Strain). Thin smears of blood were also prepared for differential leucocytes count (DLC)
while serum was used to determine the hemagglutination (HA) titre of antibodies against ND
vaccine using standard procedure as described by OIE Terrestrial Manual (OIE, 2004).
RESULTS AND DISCUSSIONS
Table 1: Trend of weekly egg production in control and treatment groups
T2 (6% nettle
T3 (12% nettle
once weekly) C (Control)
Pre trial 134 95 121 102
1 29 87 91 99
2 10 82 100 97
3 16 71 108 98
4 68 70 106 99
Sub total 123 310 405 393
After 4 weeks, 12% nettle fed group (T3) was switched to control (C) group)
5 66 61 78 61
6 87 55 100 80
7 79 49 91 78
8 75 26 77 79
9 96 39 71 80
10 85 40 58 72
Sub total 488 270 475 450
Grand total 611 580 880 843
Molted birds (T1) showed a rapid decline in egg production during molting period and reached
its peak production at 9th week after resumption of normal level of feeding. Oguike et al (2005)
had also found similar trend of post molting production and attained a peak egg production
Effect of Stinging Nettle Feeding on Productivity
by the second month. Bird of T2 group developed the habit of eating their own eggs due to
which the data on overall production was not comparable with other treatment groups. In
T3 group, the average weekly egg production increased while supplementing nettle at 12%
rate. Improvement on egg laying performance may be attributed to presence of high amount
of Ca, P, vitamins and non-specic immunomodulators in the nettle that activates the gene
responsible for egg laying (Khanal, 2008). He further indicated that a positive response of
nettle on the performance of ready to cull hens that had a signicant increase in production
after nettle supplementation. In control group, the numbers of egg laid was lesser than that of
On the 5th week of trial, the birds showed symptoms of salmonellosis and treatment was done
accordingly to all groups by providing Neodox forte (Vetcare, India Ltd.) in drinking water
for 5 days. Due to salmonellosis the egg production declined on the fth week, which could
not achieve its peak production even after treatment in all groups. Despite of manifestation
of salmonellosis in all groups, T3 (12% supplemented group) still maintained higher egg
production. Holt et al (2006) reported that the long-term feed withdrawal has been shown to
increase ileo-cecal intestinal colonization and fecal shedding of Salmonella enterica serovar
Enteritidis in challenged hens and the outbreak of Salmonellosis in the present study might be
attributed to this fact.
Assessment of Egg Quality
Table 2: Measurements of egg quality parameters
T2 (6% UD) T3 (12% UD) C (Control)
Albumen Height (mm) 5.02 ± 0.68 6.59 ± 1.08 7.09 ± 1.05* 5.72 ± 1.03
Shell Thickness (mm) 0.28 ± 0.03 0.34 ± 0.04* 0.30 ± 0.05 0.27 ± 0.023
Calcium Content (%) 1.01±0.17 1.21±0.09 1.13±0.21 1.02±0.18
Internal egg quality is frequently assessed by measurements of inner thick albumen often
measured as a function of the height of the inner thick albumen (Silversides and Villeneuve,
1994) which decreases with decreasing egg freshness (Pappas et al., 2005). The average
albumen heights in nettle supplemented birds were 7.09 ± 1.05 mm in T3 (12 % supplemented
group) which was signicantly higher (p<0.05) than C (control: 5.72 ± 1.03 mm) group (Table
2) whereas the molted group had the lowest (5.02 ± 0.68 mm). These ndings on albumin
thickness indicate that nettle supplementation in diet of layers can be benecial in improving
the egg quality.
The average shell thicknesses in both nettle supplemented groups (T2 and T3) are 0.34 ± 0.04
mm (p<0.05) and 0.3 ± 0.05 mm, respectively which are higher than 0.28 ± 0.03 mm in T1
Poudel and Khanal
(induced molted) and 0.27 ± 0.023 mm in C (control) groups as depicted in Table 2. These
differences are attributable to higher calcium content in stinging nettle that provided a better
dietary source of calcium for eggshell formation. Ronald et al (1994) have also documented
that adequate calcium in poultry diet enhances shell quality.
Calcium content of egg
Egg calcium contents in nettle supplemented groups are 1.21 ± 0.09 % in T2 and 1.13 ± 0.21
% in T3) that are higher than in non supplemented groups 1.01 ± 0.17 % in T1 and 1.02 ± 0.18
% in C) as shown in Table 2. The proximate analysis of nettle powder fed to birds has shown
very high amount of calcium of 1.11% on dry matter basis. This abundantly high amount of
calcium in egg may be attributable to abundant calcium available in nettle.
Effect of storage on egg quality
Fig. 1: Showing egg contents of
T1 group after 5 week of storage
Fig. 2: Showing egg contents of T2 group
(biweekly 6% nettle supplemented) after
5 of week storage
Fig. 3: Showing egg contents of
C (Control) group after 5 week storage
Fig. 4: Showing egg contents of T3 group
(once weekly 12% nettle supplemented)
after 5 week storage
The visible changes on egg quality after 5 weeks' storage at room temperature are shown
in Figures 1-4. These changes include decrease in albumin content and rupture of vitelline
membrane in nettle non supplemented groups (T1 and C), while albumin content was not
Effect of Stinging Nettle Feeding on Productivity
decreased in nettle supplemented group and with a more intact egg yolk depicting well
maintained vitelline membrane integrity. Decrease in vitelline membrane integrity of eggs was
also recorded by Kirunda and McKee (2000) upon one week storage of hen eggs at 25°C. The
decrease in vitelline layer strength observed during storage is associated with the dissolution
of the chalaziferous layer of the albumen, which occurs during long-term storage (Fromm,
1967; Heath, 1976). In the process of aging, water is also displaced from the egg albumen to
the yolk (Trziszka and Smolinska, 1980). The excess water in the egg yolk causes the vitelline
membrane to stretch and lose elasticity. Moran (1936) observed a similar decrease in elasticity
of the vitelline membrane with age. As nettle supplementation increased the thickness of egg
shell, thicker shell preserved the water loss and maintained egg quality. This would be a boon
to Nepal and other third world countries where many rural areas are without electricity and
refrigerator to preserve table eggs for longer duration.
Antibody titre against New Castle Disease
The result of hemagglutination inhibition (HI) test showed that birds fed with nettle powder had
higher antibody titre than induced molted layers as shown in Table 3 at the end of 10
Table 3: Antibody titre against ND in different groups
T1 T2 C T3
0th day 27272723
10th week 27282828
Similar titres were obtained in broilers supplemented with nettle powder by Piya (2006) and
Maharjan (2008). Rathore et al (1987) considered Newcastle disease HI titer above 24 as
protective level. In both T2 and T3 groups, the antibody titer was found higher than in T1
(molted group). It was not known why the nal titre in control group also remained elevated
as that of T2 and T3. The direct challenge experiment would help to assess the protective
effect of stringing nettle. On the event of possible ND outbreak, chicken supplemented with
nettle would be prepared to defend from the disease due to maintenance of protective level of
Differential Leukocyte Count
Nettle supplemented groups had comparatively higher proportion of lymphocytes than non-
supplemented groups (Table 4). A decrease in peripheral lymphocytes was observed by Safamer
(2008) in broilers challenged with aatoxin B1. It was observed that immune stimulation causes
peripheral lymphocytosis with more number of reactive lymphocytes (Kahn, 2005). Wagner
et al (1989) have also demonstrated an increased lymphocyte proliferation by nettle extract
on experimental animals. These facts indicated that nettle feeding has an immunomodulatory
action on immune system.
Poudel and Khanal
Table 4. Patterns of lymphocytes and heterophils in different groups
Groups Lymphocytes (%) Heterophils (%)
T1 (IM 68±1 22.67±0.58
T2 (6% UD) 70±2.73 20.33±1.53
T3 (12% UD) 71.33±51 20.33±1.53
C (Control) 69.33±1.53 23.33±2.3
The present ndings indicated that nettle supplementation can improve egg quality and the
vitelline membrane integrity besides enhancing antibody titre against Newcastle disease.
Maintenance of vitelline membrane integrity is very important in case of breeder hens. Nettle
can also increase the calcium content of egg and has positive inuence on egg albumen thus
favouring for more nutritious table egg. Also nettle increases the eggshell thickness, which
can subsequently reduce the cases of broken eggs and subsequent breakage losses. The effect
of nettle on total egg productivity could not be documented due to outbreak of salmonellosis,
development of egg eating habit in T2 group and occasional encroachment by rodents in
poultry shed besides shorter duration of research (10 weeks).
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