Assessment of phenotypic traits relevant for adaptation to hot environments in indigenous chickens from four agro-climatic zones of Kenya
G K Moraa, P A Oyier1, S G Maina1, M Makanda, E K Ndiema2, A E Alakonya, K J Ngeiywa3, J Lichoti3 and S C Ommeh
Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, P.O Box 6200-00200, Nairobi Kenya
sommeh@jkuat.ac.ke
1 Department of Information Technology, Jomo Kenyatta University of Agriculture and Technology, Kenya
2 Department of Earth Sciences, National Museums of Kenya
3 Department of Veterinary Services, State Department of livestock, Ministry of Agriculture Livestock and Fisheries, Kenya
Abstract
Indigenous chickens are robust in adapting to their environments.
However, global warming due to the ongoing climate change especially in
the horn of Africa has made indigenous chickens vulnerable to conditions
such as heat stress. We conducted a study on 296 indigenous chickens
from four agro-climatic zones of Kenya: Lamu archipelago, Mt. Elgon
catchment, Lake Victoria basin and Lake Turkana basin. We report
significant interactions between comb types in response to outside
temperature in the various agro climatic zones. Plumage density was
significant to the body temperature of indigenous chickens. However, we
did not see any significant relationship between the crested and
feathered shank phenotype, morphological traits such as skin colour,
comb colours, earlobe colours, shank colours and wattle colour to the
outside temperature. The outside temperatures in the various agro
climatic zones were not similar.
We characterized indigenous chickens based on their phenotypic,
morphological and physiological traits relevant for adaptation to hot
environment. We analysed our data using R Core statistics package
version 3.1.2 and Microsoft excel spread sheet. Our results indicate
that chickens from Lamu archipelago and Lake Turkana basin have various
comb types unlike the other regions. Overall yellow was the predominant
shank colour while white was the predominant earlobe colour followed
closely by yellow. All chickens from Mt. Elgon catchment had dense
plumage while chickens from the other zones had normal plumage. We also
sampled various phenotypes in the four zones. In Lamu archipelago Kuchi
phenotype was predominant while bantam phenotype was only common to Lake
Turkana basin.
Generally, this study has revealed that some traits could be of
importance for adaptation of indigenous chickens to hot environments.
Further studies should be carried out to characterize these traits in
indigenous chickens found in other arid and semi-arid regions of Kenya.
This will improve efforts to promote their conservation and improvement
through sustainable use.
Key words: climate change, diversity, heat stress, horn of Africa, poultry
Introduction
Poultry farming in Kenya is identified as one of the lead livestock
enterprises and it’s also fast growing (Nyaga 2007). Out of the 31.8
million domesticated birds in Kenya, 70% comprise indigenous chickens
(25,756,487) whereas commercial chickens are 6,071,042 (KBS 2009).
Indigenous chickens are mostly found in the rural areas and are good
scavengers, have good maternal qualities, have high survival rates and
are hardier compared to the exotic breeds (Kingori et al 2010). They are
raised under extensive free systems (Sonaiya 1990; Kitalyi 1998). This
system exposes them to harsh conditions such as extreme weather changes
being experienced in the horn of Africa often leading to decreased
productivity (Okeno et al 2012).
Chicken suffer high temperature because the feather coverage hinders
internal heat dissipation. Decreased feather coverage provides relative
heat tolerance (Yalcin et al 1997). Exposure of chickens to high
temperature results in changes at the metabolic, physiological and
cellular levels. This in turn leads to decrease in feed consumption and
chicken weight consequently leading to low efficiency and productivity
in hot climates (Coble et al 2013; Etches et al 2008). This is a
challenge especially to chickens found in hot environments. Several
studies have been done on various chicken phenotypes to assess their
performance in hot environments. A study conducted by Cahaner et al
(2008) indicated that the naked neck gene can be used to alleviate heat
stress. Interestingly, the naked neck genotype has been shown to affect
heat dissipation traits like the wattle length, rectal and surface
temperature measurements (Chen et al 2008).
The frizzled genotype has also been studied in chickens exposed to high
ambient temperatures. This gene has beneficial effects in decreasing
heat stress in poultry production (Zerjal et al 2013). In addition to
the naked neck and the frizzled gene, the dwarf gene has been shown to
have no value with regard to chicken tolerance to chronic heat stress
(Deeb and Cahaner 2001). Other than the phenotypes, some studies have
also been conducted on some morphological traits of indigenous chickens.
Studies by Duguma (2006; 2009) characterized some indigenous chicken
ecotypes of Ethiopia. These studies looked at some morphological traits
such as plumage colour, earlobe colour, comb colour, skin colour among
other traits in various indigenous chicken ecotypes in Ethiopia. These
studies indicated that chickens found in the highland areas of Ethiopia
differed from those found in the lowlands. Guni and Katule (2013)
characterised some indigenous chickens in selected southern highlands of
Tanzania. This study looked at some morphological traits and it revealed
that frequencies of various plumage forms and colours vary from one
location to another. We therefore aimed to describe the phenotypic
traits in indigenous chickens found in hot environments in Kenya.
Materials and methods
Study area
This study was conducted in Lake Turkana basin, Lamu archipelago, Lake
Victoria basin and Mt. Elgon catchment. These were the preferred areas
since Mt. Elgon catchment and Lake Turkana basin experience extreme
climatic conditions whereas Lake Victoria basin and Lamu archipelago
experience intermediate weather conditions. Besides, some of these areas
were not adversely affected by the cockerel and pullet exchange
programme. Mt. Elgon is located at an altitude of 3000m above sea level.
It is positioned between 0°27'38.76' South latitude and 34°6'41.26' East
longitude. It is also found in zone I and II of the agro-climatic zones
of Kenya. These two zones are considered wet and they are characterized
by an annual rainfall of 1000mm per annum and an annual temperature of
0°C minimum and 22.0°C maximum. Some of the areas are moorland areas and
communities have been found to keep livestock including indigenous
chickens. Lake Victoria basin lies in zone III and receives an annual
rainfall of 500-1000 mm with an annual temperature of 17.1°C minimum and
to 29.4°C maximum. It is situated between 0°24'41.74' South latitude and
34°9'51.55' East longitude. Lamu is located between 2°16'10.41' South
latitude and 40°54'2.31' East longitude. It lies within zones IV of the
agro-climatic zones, this zone is considered dry and humid and receives
an annual rainfall of 800mm and an annual temperature of 24.1°C minimum
and 29.2°C maximum. Turkana basin is positioned between 3°37'36.55'
South latitude and 36°0'8.35' East longitude. It lies within zone VI and
zone VII of the agro- climatic zones of Kenya. These zones are
characterized by annual rainfall of 200-600 mm which is quite unreliable
since crops and livestock can hardly survive in this environment. It’s
also characterized by an annual temperature of 23.7°C minimum and 42°C
maximum. These zones are considered as deserts and they are the driest
part of Kenya.
|
Table 1.
Summary of sampled locations
|
|
Agro climatic zone
|
Population
|
Number of samples
|
|
Lake Turkana basin
|
Lake Turkana East
|
33
|
|
|
Lake Turkana West
|
61
|
|
|
Total
|
94
|
|
Lamu Archipelago
|
Lamu North
|
27
|
|
|
Lamu central
|
30
|
|
|
Lamu South
|
46
|
|
|
Total
|
103
|
|
Lake Victoria Basin
|
Homabay
|
24
|
|
|
Total
|
24
|
|
Mt. Elgon catchment
|
Mt.Elgon north
|
31
|
|
|
Mt. Elgon south
|
44
|
|
|
Total
|
75
|
|
|
Total samples
|
296
|
Data collection
We conducted field surveys in remote villages that were not affected by
the cockerel and pullet exchange programme in the four agro-climatic
zones. We conducted Interviews at the farmers’ houses with the
assistance of local agricultural extension officers. We used a
pre-tested questionnaire on open data kit (ODK) on phones to obtain the
morphological and physiological data of the indigenous chickens based on
adaptation to hot environments. We characterised a total of 296
genetically unrelated adult indigenous chickens from 10 populations each
having 20-30 individuals. Some of the phenotypic attributes we studied
include; skin colour, shank colour, comb type, comb colour, earlobe
colour, wattle colour, presence of a crest and presence of feathers in
the shank and plumage density. Plumage density was characterised as
dense (presence of feathers under the wings, on the thighs, shanks and
in the breast bone); normal plumage chickens had average feathers on
their bodies while in scarce plumage chickens had very few feather
coverage on their bodies. We also took measurements of the body
temperature as a physiological trait, outside temperature and global
positioning system (GPS).
Data Analysis
We analysed our data using Excel spread sheet software package 2013 to
compute frequencies of occurrence of each trait. We also used ANOVA
tests in R core statistics software version 3.1.2 to determine
relationships between various traits and the ecosystems in response to
outside temperature. We used a box plot in R to show if any relationship
exists between the outside temperature and the various agro climatic
zones. To determine the relationship between outside temperature and
body temperature in the various agro-climatic zones we used a
conditioning plot.
Results and Discussion
|
Table 2.
Distribution (%) of various phenotypes in the agro climatic zones of Kenya
|
|
Phenotypes
|
Agro climatic zones
|
|
Lamu archipelago
(n=103)
|
%
|
Lake Turkana basin
(n=94)
|
%
|
Lake Victoria basin
(n=24)
|
%
|
Mt. Elgon catchment
(n=75)
|
%
|
Total
|
%
|
|
Frizzled
|
2.00
|
50.0
|
0.00
|
0.00
|
0.00
|
0.00
|
2.00
|
50.0
|
4.00
|
0.84
|
|
Bantam
|
0.00
|
0.00
|
39.0
|
100
|
0.00
|
0.00
|
0.00
|
0.00
|
39.0
|
8.21
|
|
Rumpless
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
1.00
|
100
|
1.00
|
0.21
|
|
Kuchi
|
103
|
100
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
103
|
21.7
|
|
Mixed
|
59.0
|
26.3
|
83.0
|
37.1
|
18.0
|
0.08
|
64.0
|
0.28
|
224
|
47.2
|
|
Naked neck
|
2.00
|
0.13
|
5.00
|
0.33
|
3.00
|
0.20
|
5.00
|
0.33
|
15.0
|
3.16
|
|
Plain feathered
|
8.00
|
0.40
|
9.00
|
0.45
|
0.00
|
0.00
|
3.00
|
0.15
|
20.0
|
4.21
|
|
Crested
|
0.00
|
0.00
|
6.00
|
0.27
|
1.00
|
0.05
|
15.0
|
0.68
|
22.0
|
4.63
|
|
Mottled
|
0.00
|
0.00
|
7.00
|
0.58
|
3.00
|
0.25
|
2.00
|
0.17
|
12.0
|
2.53
|
|
Barred Feathers
|
1.00
|
0.05
|
3.00
|
0.14
|
6.00
|
0.29
|
11.0
|
0.52
|
21.0
|
4.42
|
|
Feathered shanks
|
0.00
|
0.00
|
1.00
|
0.07
|
0.00
|
0.00
|
13.0
|
0.93
|
14.0
|
2.95
|
|
Table 3.
Proportionate (%) occurrence of morphological traits of indigenous chickens in various agro-climatic zones
|
|
|
|
Agro-climatic zones
|
|
Character
|
Expression
|
Mt.Elgon catchment
(n=75)
|
Lake
Victoria basin
(n=24)
|
Lake
Turkana basin
(n=94)
|
Lamu Archipelago
(n=103)
|
|
Comb type
|
Single
Walnut
Cushion
Pea
Rose
Strawberry
|
96.0%
0.00%
0.00%
0.00%
0.00%
1.33%
|
95.8%
0.00%
0.00%
0.00%
0.00%
4.17%
|
84.0%
0.00%
1.06%
0.00%
11.7%
3.19%
|
3.88%
7.77%
0.97%
12.6%
5.83%
68.9%
|
|
Comb colour
|
Red
Pale
Black
|
90.6%
9.33%
0.00%
|
70.8%
29.1%
0.00%
|
85.1%
13.8%
1.06%
|
48.5%
51.5%
0.00%
|
|
Earlobe colour
|
Red
Yellow
Black
White
|
21.3%
32.0%
1.33%
45.3%
|
45.8%
45.8%
0.00%
8.33%
|
11.7%
5.32%
2.13%
80.8%
|
22.3%
5.83%
0.00%
71.8%
|
|
Wattle colour
|
Red
Pale
Black
|
89.3%
9.33%
1.33%
|
70.8%
29.2%
0.00%
|
85.1%
14.8%
0.00%
|
48.5%
51.4%
0.00%
|
|
Skin colour
|
White
Yellow
Cream
Grey
|
61.3%
36.0%
1.33%
1.33%
|
29.2%
70.8%
0.00%
0.00%
|
90.4%
8.50%
1.10%
0.00%
|
96.1%
3.90%
0.00%
0.00%
|
|
Shank colour
|
White
Yellow
Grey
Black
Green
Cream
|
33.3%
52.0%
8.00%
4.00%
2.67%
0.00%
|
25.0%
70.8%
4.16%
0.00%
0.00%
0.00%
|
68.1%
20.2%
6.38%
4.26%
0.00%
1.06%
|
43.7%
54.4%
0.00%
1.94%
0.00%
0.97%
|
|
Plumage density
|
Dense
Normal
Scarce
|
82.7%
17.3%
0.00%
|
0.00%
100%
0.00%
|
0.00%
100%
0.00%
|
0.00%
98.1%
1.94%
|
Comb type and comb colour
We observed different comb types (single, strawberry, rose, walnut, cushion,
pea, and buttercup) in the four agro-climatic zones. Out of the total
proportion studied, single comb was predominant in Mt. Elgon catchment, Lake
Victoria basin and Lake Turkana basin. Interestingly, strawberry comb was
predominant in Lamu archipelago. Additionally, all comb types were observed
in this region. Mt Elgon catchment and Lake Victoria basin had only single
and strawberry comb types. Lake Turkana basin had single, cushion rose and
strawberry combs. These results have indicated that various comb types exist
in various regions and in various chicken phenotypes. Msoffe et al (2001)
also indicated that certain comb types occur more frequently in some chicken
ecotypes than in others. Other research findings (Apuno et al 2011; Guni and
Katule 2013; El-Safty 2012) reported the predominant occurrence of single
comb type in indigenous chicken populations. The appearance of various comb
types could be due to adaptation to suit into various agro climatic zones
which might be brought about by gene mutations.
We observed three comb colours: red, pale and black. Red combs were
predominant in Mt. Elgon catchment, Lake Victoria basin and Lake Turkana
basin. However, pale colour was common in Lamu archipelago. This report
reflects what was reported by Guni and Katule (2013) that Red and pale
colours were common in Tanzanian chicken ecotypes, and Faruque et al
(2010) whose study showed the occurrence of red combs in Bangladesh chickens.
Ear lobe colour and Wattle colour
We observed red, white, yellow and black earlobes. White was the predominant
earlobe colour. This was followed by yellow and red earlobes. Theses colours
varied across all the agro climatic zones. We also observed low frequencies
of black earlobes in Mt. Elgon catchment and Lake Turkana basin. The results
of this study are similar to those reported by (Egahi et al 2010; Guni and
Katule 2013; Iqbal and Pampori 2008). These studies reported differences in
earlobe colours among indigenous chickens. Variations in earlobe colours
have been thought to be of genetic origin since earlobe colour is dependent
upon several genetic factors (Guni and Katule 2013).
We observed three wattle colours; red, pale and black. Red wattles were
common in Mt. Elgon catchment, Lake Victoria and Lake Turkana basins.
Interestingly, most of the chickens in Lamu archipelago had pale earlobes.
Pale wattles were also observed in the other agro climatic zones. In
addition to red and pale colours, we also observed black wattles in Mt Elgon
catchment but in very low frequencies. These results are similar to reports
by (Kingori et al 2010) on wattle colours in indigenous chickens.
Skin colour and shank colour
We observed differences in skin colour across the four agro climatic zones
that were white, yellow, cream and grey skin colours. White was the predominant
skin colour in Lamu archipelago, Mt. Elgon catchment and Lake Turkana basin.
Interestingly in Lake Victoria basin, yellow was the predominant skin
colour. All colours were observed in Mt. Elgon catchment. These results are
similar to those reported by (Guni and Katule 2013; Kingori et al 2010;
Msoffe et al 2001). However these results contrast with those from Dana et al
(2010) who reported yellow skin to be the most predominant skin colour in
Ethiopian chickens.
We observed different shank colours (white, yellow, cream, black, grey and
green) across the four agro climatic zones. Overall yellow shanks were most
common across the agro climatic zones. These results are similar to reports
by Cabarles et al (2012), Guni and Katule (2013) and Msoffe et al (2001).
Conversely, these results differ from those observed by Egahi et al (2010)
and El-Safty (2012) who reported black as the predominant skin colour. This
was followed closely by white shanks. We only observed green shanks in Mt.
Elgon catchments though in low frequencies. We didn’t observe any black
shanks in Lake Turkana basin. Lamu archipelago was the only regions where we
didn’t observe grey shanks. Cream shanks were common in Lake Turkana basin
and Lamu archipelago though in small frequencies. These results have shown
variation in shank colours across the various agro climatic zones and this
is in agreement with a research conducted by Msoffe et al (2001).
Plumage density
We observed normal plumage densities across the three agro climatic zones
except Mt. Elgon catchment. All chickens from Mt. Elgon catchment which
experiences cold climate had dense plumage. This could be an adaptation to
enable them conserve enough heat since feather coverage hinders heat loss
(Yalcin et al 1997).
|
Table 4.
ANOVA results of relationship between various traits in response to the outside temperature
|
|
Trait response to outside temperature
|
p
|
|
Comb type
|
0.05
|
|
Comb colour
|
1.0
|
|
Earlobe colour
|
1.0
|
|
Wattle colour
|
1.0
|
|
Skin colour
|
0.10
|
|
Shank colour
|
1.0
|
|
Plumage density
|
0.001
|
|
Phenotype crested
|
0.10
|
|
phenotype feathered shank
|
0.66
|
|
Agro-climatic zones
|
0.001
|
Relationship between various traits, in response to the outside
temperature
In general this study has shown significant interaction between comb types,
and plumage density to the outside temperature in the various agro climatic
zones. Overall, single comb was predominant in all zones. However, Lake
Turkana basin and Lamu archipelago had varied comb types. Dense plumage was
only specific to Mt. Elgon catchment while the other regions had normal
plumage. There was also a significant relationship between the various agro
climatic zones to the outside temperature.
This study did not show significant interaction between the comb, earlobe,
wattle, skin and shank colours to the outside temperature. It is also worth
noting that this study did not show any significance between the crested and
feathered shank phenotype to the outside temperature. This could be
attributed to the low frequencies of these phenotypes observed during
sampling.
Relationship between agro-climatic zones and various traits, in
response to the outside temperature
|
Table 5.
ANOVA results of analysis of ecosystem, and various traits in response to the outside temperature
|
|
Trait response to outside temperature
|
p
|
|
Agro-climatic zones and comb colour
|
0.10
|
|
Agro-climatic zones and comb type
|
0.10
|
|
Agro-climatic zones and earlobe colour
|
0.10
|
|
Agro-climatic zones and wattle colour
|
1.00
|
|
Agro-climatic zones and shank colour
|
1.00
|
|
Agro-climatic zones and skin colour
|
1.00
|
|
Agro-climatic zone and plumage density
|
0.05
|
|
Agro-climatic zone and phenotype crested
|
0.80
|
|
Agro-climatic zone and phenotype feathered shank
|
0.90
|
This study also tried to find out whether there is any significant
interaction between the agro climatic zones and various traits in response
to outside temperature. We found out that there is a significant
relationship between the agro climatic zones and plumage density to the
outside temperature. However, we did not see any significant relationship
between the agro climatic zones and comb colour, comb type, earlobe colour,
wattle colour, shank colour and skin colour to the outside temperature.
Also, no significance was observed between the agro climatic zones, crested
and feathered shank phenotypes in response to the outside temperature.
 |
|
Figure 2. Box plot showing the relationship between outside
temperature and various agro climatic zones |
To determine whether outside temperature across the four agro climatic zones
was uniform, we obtained a box plot using R core statistical package. This
indicated that outside temperature was not uniform across the four agro
climatic zones. Lake Turkana basin recorded the highest temperatures and
this was followed by Lamu archipelago then Lake Victoria basin. Mt. Elgon
catchment recorded the least temperature. This is in line with the works of
Jaetzold and Schmidt (1983) and Paron et al (2013) about outside temperatures
in these regions.
 |
|
Figure 3. A conditioning plot illustrating the relationship between body temperature
and outside temperature
|
We also drew a conditioning plot of body temperature against outside
temperature in the four agro climatic zones. We found out that chickens in
Lake Turkana basin had very high temperatures followed by chickens from Lamu
archipelago. Lake Turkana basin and Lamu archipelago are characterised by
high temperatures since they are arid and semi-arid lands respectively.
Chickens from Mt. Elgon catchment had the least temperatures. This could be
due to the cold climate experienced in this region.
Conclusions
- There was significance in various morphological traits such as comb type,
skin colour, and plumage density in response to outside temperature in the
four agro climatic zones of Kenya.
- The agro climatic zones and the comb colour plus the agro climatic zones
and the earlobe colours were significant to the outside temperature.
- There was significance in the various agro climatic zones in response to
outside temperature.
- This study did not show significant interactions between the crested and
the feathered shank phenotype in response to outside temperature in the four
agro climatic zones.
Recommendations
- The samples we used in this study were from chickens in their natural
ecological setting and not from a laboratory controlled experiment with
heat-stress.
- The study only focused on the phenotypic aspect of adaptation
to hot environments therefore further controlled experiments should be
carried out to ascertain these phenotypes.
- Findings from this study should direct further research to investigate the
role of factors such as genetics, feed intake, metabolic heat production,
disease status and appetite among others.
- Studies should also be done in chickens from other arid and semi-arid
lands of Kenya.
Acknowledgment
The authors wish to thank the Department of Veterinary
Services under the Ministry of Agriculture Livestock and Fisheries for
supporting this research. Appreciation is also extended to the extension
officers and the farmers for their co-operation during data collection.This
research was funded through a research grant JKU/2/4/RP/181 awarded to Dr.
Sheila Ommeh by Jomo Kenyatta University of Agriculture and Technology.
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Received 1 July 2015; Accepted 23 August 2015; Published 1 October 2015
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