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Italian Journal of Animal Science
ISSN: (Print) 1828-051X (Online) Journal homepage: http://www.tandfonline.com/loi/tjas20
Adaptation to organic rearing system of eight
different chicken genotypes: behaviour, welfare
and performance
Cesare Castellini, Cecilia Mugnai, Livia Moscati, Simona Mattioli, Monica
Guarino Amato, Alice Cartoni Mancinelli & Alessandro Dal Bosco
To cite this article: Cesare Castellini, Cecilia Mugnai, Livia Moscati, Simona Mattioli, Monica
Guarino Amato, Alice Cartoni Mancinelli & Alessandro Dal Bosco (2016): Adaptation to organic
rearing system of eight different chicken genotypes: behaviour, welfare and performance,
Italian Journal of Animal Science
To link to this article: http://dx.doi.org/10.1080/1828051X.2015.1131893
© 2016 The Author(s).
Published online: 25 Feb 2016.
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PAPER
Adaptation to organic rearing system of eight different chicken genotypes:
behaviour, welfare and performance
Cesare Castellini
a
,Cecilia Mugnai
b
,Livia Moscati
c
,Simona Mattioli
a
,Monica Guarino Amato
d
,
Alice Cartoni Mancinelli
a
and Alessandro Dal Bosco
a
a
Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Perugia, Italy;
b
Dipartimento di Scienze degli Alimenti,
University of Teramo, Teramo, Italy;
c
Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche, Perugia, Italy;
d
Consiglio per la
Ricerca e la Sperimentazione in Agricoltura, Ministero delle Politiche Agricole Alimentari e Forestali, Roma, Italy
ABSTRACT
The aim of the study was to define poultry adaptability to organic system, through the assess-
ment of several endpoints. Eight hundred male birds of slow-growing birds (Ancona: A, Leghorn:
L, crossbreed Cornish Leghorn: CL), medium-growing (Gaina: G, Robusta Maculata: RM, Kabir: K,
Naked Neck: NN) and fast-growing strains (Ross: R) were organically reared. A and L genotypes
displayed a quicker reaction time when submitted to tonic immobility test, and a great variety of
behaviour and exploiting all the pasture area. Concerning feather conditions L, A, CL G and RM
showed the best values for all considered body regions, as well as the absolute absence of foot
pad and breast blister lesions. Static behaviour of R and G chickens did not produce a significant
oxidative burst whereas, the active behaviour of A, slow-growing birds, increased the oxygen de-
mand. Plasma a-tocopherol followed the trend of kinetic and foraging activity being higher in
slow-, intermediate in medium- and lower in fast-growing birds. The adaptability index showed
the best result of slow-growing strains with intermediate results in medium-growing and the
worst in fast-growing ones. There is a negative linear correlation between adaptation and daily
weight gain. However, within the same sub-group (slow, medium and fast), there is no correlation
between daily weight gain and adaptation to an organic system. Even if R chickens had the high-
est productive performance, they appeared no adapted to the organic system. Daily weight gain
(<50 g/d) is a prerequisite for chicken adaptation, but even birds with similar weight gains
showed wide variations in the adaptation.
ARTICLE HISTORY
Received 27 August 2015
Accepted 11 December 2015
KEYWORDS
Behaviour; chicken
genotype; organic rearing
system; performance;
welfare
Introduction
The Article 12 of Regulation (EC) n. 889/2008 pro-
vides that each Member State has to define the cri-
teria for the definition of slow-growing poultry
genotypes and to evaluate their adaptability to the
organic system. This regulation establishes that ‘.in
organic livestock production, the choice of breeds
should take into account of their capacity to adapt
to local conditions, their vitality and their resistance
to disease and a wide biological diversity should be
encouraged.’ Therefore, the best equilibrium between
animal welfare, adaptability to environment, biodiver-
sity and productive performance should be found.
Within the European Union, the choice of genotypes
is based only on the daily weight gain; others have
opted for egg-type chickens, but the definition of
slow-growth and the relationship between growing
rate and adaptability to the organic system is still
unclear.
There are cases where improvement of welfare
determines a reduction of the production costs (e.g.
decrease disease and mortality) and an increase of
people’s perceptions related to sustainable systems
(Napolitano et al. 2013). On the other hand, some be-
havioural pattern (e.g. kinetic and foraging activity),
positively related to the bird welfare and meat quality,
negatively affect the weight gain (Branciari et al. 2009).
On the basis of these considerations, the aim of the
present study was to evaluate the behavioural aspects
and welfare indicators of eight different chicken geno-
types through a multifunctional approach (behaviour,
tonic immobility (TI), feathers condition, presence of
body lesions, antioxidant and immune status) in order
to assess their adaptability to organic system.
CONTACT Cesare Castellini cesare.castellini@unipg.it Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Universit
a di Perugia, Borgo XX
Giugno 74, Perugia 06100, Italy
ß2016 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/
licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
ITALIAN JOURNAL OF ANIMAL SCIENCE, 2016
http://dx.doi.org/10.1080/1828051X.2015.1131893
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Materials and methods
Birds, diets and slaughtering
The trial was performed at the experimental section
of the Department of Agricultural, Food and
Environmental Science of Perugia (Italy) from
September to November 2013 and chickens were
reared according to EU Regulation 834/07, EU
Regulation 889/2008 and Italian directives (Italian
Regulation 1992) on animal welfare for experimental
and other scientific purposes.
Eight hundred male birds of the following genotypes
(100 animals/genotype) were compared: Ancona (A),
Leghorn (L), crossbreed Cornish Leghorn (CL), Kabir
(K), Naked Neck (NN), Robusta Maculata (RM), Gaina (G)
and Ross 308 (R). On the basis of our previous studies
(Castellini et al. 2002a, 2002b; Dal Bosco et al. 2014a,
2014b) and commercial information, the genotypes
were sub-categorised with regard to their growth rate:
slow (GR <24 g/d; A, L, CL), medium (25 <GR 40 g/d;
G, RM, K, NN) or fast-growing (GR >41 g/d; R).
The L, A and RM genotypes originated from conser-
vation flocks maintained at the Department of
Agricultural, Food and Environmental Science of
Perugia since the 1960s. CL chicks were produced by
crossing L hens with Cornish fowl, whereas G, K, NN
and Ross 308 were furnished by a commercial poultry
farm (Avicola Berlanda, Italy).
Chickens were kept after hatching until 20 d of age
in a poultry house in separate pens, with temperatures
ranging from 20 to 32 C and with relative humidity
ranging from 65 to 75%. Incandescent light (30 lux)
placed at bird level was used for heating and illumin-
ation. Chicks were vaccinated against Marek and
Newcastle diseases.
At 21 d of age, chicks were transferred to straw-
bedded indoor pens (0.10 m
2
/bird), each equipped
with feeders and drinkers and with free access
to forage paddock (4 m
2
/bird). Each genetic strain
was replicated in four pens containing 25 chicks
each. Birds were confined to indoor pens during the
night.
The pasture was not treated with pesticides or her-
bicides during the 3 years prior to organic production.
The pasture also contained mature trees, bushes and
hedges.
Birds were raised until the minimum slaughter
age (81 d).
Chickens were fed ad libitum the same experimental
starter (1–21 d) and grower-finisher (22 d to slaughter)
diets containing organic ingredients, with the excep-
tion of 5% of GM-free soybean meal and vitamin-min-
eral premix (Table 1).
Access to feed and water was freely available, and
the two diets were formulated to contain adequate nu-
trient levels as defined by the NRC (1994). Individual
body weights were recorded weekly, as well as the col-
lective feed intake of each pen. The average feed con-
sumption of the group was used to calculate the
feed:gain ratio. The number of culled and dead birds
was recorded. At 81 d, a sample of five birds per geno-
type per pen, each weighing between 610% of the
group mean, were slaughtered in the processing plant
of the Department of Agricultural, Food and
Environmental Science of Perugia, 12 h after feed with-
drawal. Just before slaughtering, birds of the six groups
were subjected to plumage scoring and blood samples
were collected.
Behavioural observation
Behavioural observations were recorded at 11 weeks of
age in a period of 5 d each. Five animals per pen were
randomly selected and marked with different colours
on the tip of the tail. Behavioural observations were
recorded during 3-h periods in the morning
(9:00–12:00) and afternoon (15:00–18:00) using the focal
animal scan sampling method (Martin & Bateson 1986).
Before each observation session, 5 min were allowed for
Table 1. Ingredients and calculated analysis of
poultry diets.
Starter Finisher
Ingredients (%)
Maize 52 46
Full fat soybean 30.5 12.5
Wheat – 20.0
Soybean meal
a
9.00 14.0
Alfalfa meal 2.80 2.80
Gluten feed 3.00 2.00
Vitamin-mineral premix
b
1.00 1.00
Dicalcium phosphate 1.00 1.00
Sodium bicarbonate 0.50 0.50
NaCl 0.20 0.20
Chemical composition
Dry matter (%) 90.9 90.8
Crude protein (%) 22.3 18.0
Ether extract (%) 7.95 4.98
Crude fibre (%) 4.67 4.01
Ash (%) 5.76 5.59
NDF – neutral detergent fibre (%) 10.7 10.1
ADF – acid detergent fibre (%) 5.58 5.06
Cellulose (%) 4.22 3.56
ADL – acid detergent lignin (%) 1.03 1.11
Hemicellulose (%) 5.16 5.05
Metabolisable energy
c
, MJ/kg 12.5 12.9
a
5% from conventional crops.
b
Amount per kg: Vit. A 11 000 U; Vit. D
3
2000 U; Vit. B
1
2.5 mg; Vit. B
2
4 mg; Vit. B
6
1.25 mg; Vit. B
12
0.01 mg;
a-tocopherol acetate 30 mg; Biotin 0.06 mg; Vit. K 2.5 mg;
Niacin 15 mg; Folic acid 0.30 mg; Pantothenic acid 10 mg;
Choline chloride 600 mg; Mn 60 mg; Fe 50 mg; Zn 15mg; I
0.5 mg and Co 0.5 mg.
c
Estimated according to Carre
`and Rozo (1990).
2 C. CASTELLINI ET AL.
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the animals to adapt to the presence of observers; in
this period, the interest shown by the birds towards the
observer and the time spent outdoors or indoors were
registered according to Lewis et al. (1997).
The behavioural observations included: feeding
(feed from feeders and water from drinkers), moving
(walking, running and foraging), resting (standing idle,
lying on the sternum), comfort (dust bathing, self-
preening, wing flapping, scratching and starching), and
others (allopreening as gentle and severe pecking
others, as described by Kjaer and Sørensen (1997)).
Birds’ behaviours were recorded on a custom-designed
table, and their respective frequencies were calculated
as a percentage of the total behaviour. Since no differ-
ences were found between days and hours, all data
were pooled to obtain a mean value.
The maximum distance from the house was calcu-
lated as the distance reached by chickens during the
observation. Time spent outdoor was expressed as the
percentage of outdoor birds with respect to the total
birds.
At the end of behavioural observation, birds were
caught and submitted to the TI test that was induced
by restraining the birds on their backs in a U-shaped
wooden cradle for 10 s (Gallup 1979). A bird was
defined as being in a state of TI if it remained immo-
bile for a minimum of 10 s after restraint had ended. A
maximum of three inductions and a test ceiling of
3 min in TI were applied. The total duration of TI, i.e.
until the bird righted itself, was recorded.
At slaughter, in all birds the plumage condition and
footpad lesions (FPD) were assessed. The plumage con-
dition evaluation was assessed following a 4-point scale
for each trait, where a score of 4 implied the best condi-
tion and a score of 1 the worst one (Tauson et al. 2005).
The six parameters (neck, breast, cloacae/vent, back,
wings and tail) for feather condition score were sum-
marised, implying a total score ranging from 6 to 24
points. The FPD was recorded by assigning different
classes to 1 of 3:0 ¼no mark (no lesion), 1 ¼mild lesions
(superficial lesions, erosions, papillae and discolouration
of the footpad), or 2 ¼severe lesions (deep lesions,
ulcers and scabs) (Berg 1998). The presence of breast
blisters (BBs) on the carcass was also recorded.
Oxidative status, native immunity and blood
parameters
Immediately before slaughter, 5-ml blood samples
were collected within 2 min of removing the birds
from its pen. After collection from the brachial vein,
blood samples were immediately sent to the laboratory
where they were centrifuged and frozen at 80 C until
analysis. Blood samples for haematocrit were collected
in heparinised capillary tubes and centrifuged in a
micro haematocrit centrifuge for 7 min.
Reactive oxygen species (ROS) and the antioxidant
power of plasma (AP) of the samples were evaluated
by a commercial kit (Diacron, Grosseto, Italy). The a-
tocopherol level of plasma was assessed according to
Schuep and Rettenmeier (1994).
The haemolytic complement assay (HCA) was car-
ried out in microtitre plates (Seyfarth 1976). The com-
plement titre is the reciprocal of the serum dilution
causing 50% lyses of red blood cells (RBC) of ram
(CH50). The volumes of the reagents were modified to
perform the test in microtitre plates at a final volume
of 125 ll/well (100 ll of serum dilutions þ25 llof3%
rabbit erythrocytes). The 0 and 100% haemolysis con-
trols were set up in each plate at the same volume in
Veronal buffer (pH 7.3) and distilled water, respectively.
Titres were expressed as 50% haemolytic units per 100
microlitres (the test volume of sera).
The serum bactericidal activity (SBA) was performed
according to a previous method validated for cattle
(Amadori et al. 1997). The test is based on the growth
of non-pathogenic Escherichia coli until long phase in
20 ml of brain heart infusion broth; for each test, one
aliquot was incubated at 37 C until an optical density
of 590 nm. Then, bacteria were diluted 1:100 in sterile
saline solution. Test reagents were distributed into
wells of sterile, U-bottomed microtitre plates according
to the following scheme: 50 ll of test serum (in dupli-
cate) added to 50 ll of Veronal buffer, 100 ll of BHI
broth, and 10 ll of 1:100-diluted bacterial suspension.
Controls of sterility were set up without bacteria (nega-
tive control). Controls of bacterial growth (positive con-
trol) were set up without serum. The missing
components were replaced by Veronal buffer at the
same volumes. Plates were incubated in a humidified
box at 37 C for 18 h. They were then read spectro-
photometrically in an ELISA reader at 690 nm, with a
blank set on the sterility control. Its concentration was
expressed in %.
Serum lysozyme was measured by a lyso-plate assay
(Osserman & Lawlor 1966), carried out at 37 C for
18 min, in a humidified incubator. Briefly, serum sam-
ples were reacted with a suspension of Micrococcus
lysodeikticus inside an agar gel in 10 cm Petri dishes
and then distributed in duplicate in 3 mm holes, 2 cm
apart, at a regular distance of 1.5 cm from the dish
edge. The reaction was carried out in a humidified in-
cubator for 18 h at 37 C. The diameter of the lysed
areas around serum samples and lysozyme standards
of known concentration in phosphate buffer (0.066 M,
pH 6.3) was assessed by callipers or rules. Under these
ITALIAN JOURNAL OF ANIMAL SCIENCE 3
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conditions, lysozyme concentration (lg/ml) was pro-
portional to the diameter of lysed areas and was deter-
mined from a standard curve created with reference
preparations of egg white lysozyme (Sigma-Aldrich,
St. Louis, MO).
The leukocyte counts have been done on two drops
of blood, and blood smears were made on duplicate
glass slides. Both the slides were counted and the
means were calculated for each bird. These smears
were stained with Wright stain in 15 min. One hundred
leucocytes, including heterophils (H), lymphocytes (L),
monocytes, eosinophils, basophils, RBC, haemoglobin
(HGB), haematocrit and platelets (PLT) were counted
on each slide. The H:L ratio was also calculated.
Statistical analyses
The data were analysed with a linear model (STATA
2005) to evaluate the effect of the genotype; the sig-
nificance of differences (p<0.05) was evaluated by
multiple t-tests. Linear regression analysis was also per-
formed to verify the adaptability score in relation to
the daily weight gain.
Adaptability index
On the 49 different traits recorded for each bird, a
rank of adaptability (from 0 low to 7 high; STATA; proc
ROWRANK) has been calculated. The sum of the differ-
ent scores was calculated and the final ranking of
adaptability was then calculated and normalised
(mean ¼1; proc STATA). Differences in ethogram,
culled birds and mortality rates were evaluated by the
X
2
(proc. FREQ).
Results and discussion
The ethogram of the eight genotypes is summarised in
Table 2. The R genotype showed the lower initial inter-
est, like G and K ones; other medium-growing strains
(RM and NN) reached intermediate values. On the
other hand, L, A and CL had the highest percentages;
the L and A chickens spent about 60% of their budget
time outdoor and performed much of their behaviour
patterns far (18.1 and 17.5 m, respectively) from the
shelter exploiting all the available space. Together with
CL, these birds showed a significantly higher percent-
age of kinetic behaviour, while only the 7.0% of this
behaviour was observed in R chickens.
On the contrary, the eating and the resting behav-
iours were less frequents in the slow-growing chickens
and much more relevant in R and G chickens whereas
K and NN birds showed for eating intermediate values.
Regarding resting behaviour, K and R chickens had the
highest value.
Behavioural observation confirmed that the R geno-
type had the worst results in term of initial interest
and spent more time indoor than outdoor. In contrast,
the slow-growing birds displayed a great variety of be-
haviour patterns and exploiting all the available pas-
ture area. Medium-growing birds had intermediate
results in term of initial interest, time spent outdoor
and complexity of behaviours. Lewis et al. (1997), com-
paring chickens with different growth rate, observed
marked differences in the behaviour of birds; in par-
ticular, slow-growing genotype were much more active
and more interested to the observer, made greater use
of the perches and fewer are at rest. Slow-growing
genotypes showed a better ability to exploit the pas-
ture, with many positive metabolic and qualitative out-
comes (Dal Bosco et al. 2012). Indeed, in previous
studies (Castellini et al. 2002a; Fanatico et al. 2005), it is
stated that the level of activity was correlated with the
foraging behaviour which is fundamental for fully
exploiting the natural resources available.
R chickens are more inactive confirming the findings
of Gordon and Charles (2002). Weeks et al. (1994) com-
pared the behaviour of Ross broilers, reared under
free-range or kept inside, showed that free-range birds
tended to stay indoors and/or near the house, rather
than forage in the pasture. The authors attributed this
behaviour mainly to leg weakness, which prevented
Table 2. Ethogram (%) of different poultry genotypes.
L A CL G RM K NN R v
2
Initial interest
1
%65
c
62
c
60
c
45
ab
50
b
45
ab
55
b
30
a
0.25
Time spent outdoor % of total time 60
d
62
d
56
c
46
bc
49
bc
42
b
55
c
19
a
15
Distance from house m 18.1
c
17.5
c
15.3
bc
11.6
b
15.3
b
11.2
b
14.5
bc
4.9
a
12.4
Eating % 3.6
a
2.1
a
3.6
a
33.2
c
4.5
a
18.4
b
19.4
b
37.0
c
13.2
Moving ‘‘ 71.5
d
51.2
c
50.6
c
25.4
b
40.6
bc
20.3
b
35.0
b
7.0
a
34.1
Resting ‘‘ 21.6
a
34.3
ab
34.9
ab
40.0
ab
37.3
ab
60.2
c
45.0
ab
55.5
bc
25.1
Comfort ‘‘ 2.0
ab
3.0
b
3.2
b
0.2
a
3.1
b
1.0
ab
0.2
a
0.5
a
2.1
Other behaviour ‘‘ 1.2
b
9.3
c
7.4
c
1.0
b
14.2
d
0.0
a
0.0
a
0.0
a
4.2
N: five birds/four replications per genotype.
L, Leghorn; A, Ancona; CL, crossbreed Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck; R, Ross.
a...d
Values within a row with different superscripts differ significantly at p<0.05.
1
Interest shown by the birds towards the observer on the first 5 min of the presence in pen.
4 C. CASTELLINI ET AL.
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the birds from pasturing and behaving naturally. Fast-
growing chickens showed severe difficulties in move-
ment caused by the high body and breast weights,
which obliged the animals to bed resting, especially in
the last days of rearing. The reduction of kinetic activ-
ity is a major cause of leg weakness and the long rest-
ing in litter produces skin lesions (Elfadil et al. 1996;
Bokkers & Koene 2004).
In our trial, the feeding behaviour (eating from
feeders) was less present in the slow-growing strains
whereas, fast-growing birds rested in a group around
the feeders in accordance with Fanatico et al. (2005).
The animal selection has focused on maximising the
productive traits inducing animals to allocate their
resources to body growth, reducing their ability to re-
spond to other physiological and ethological demands
(e.g. response to environmental stimuli, immunity,
scavenging activity). Accordingly, such selection pres-
sure reduced the level of bird activity (Dunnington
1990). Our results confirm such assumption: R birds
had a higher feed intake, which covers the energy ex-
penditure of high meat production. On the contrary,
slow- and somewhat medium-growing birds showed
the lowest feeding efficiency and feed intake and per-
formed less resting in favour of kinetic (walking, run-
ning, foraging and exploring) activities.
The TI test, feather conditions, FPD and BB lesions
of the eight poultry strains are presented in Table 3.
The A, L and RM birds showed a quicker reaction time
(<50 s); CL and NN showed intermediate times (about
60 s), whereas, K, G and R ones the highest values (97,
111 and 126 s, respectively).
Concerning feather conditions the L, A, CL, G and
RM chickens showed the best values for all considered
body regions, as well as the absolute absence of FPD
and BB lesions. A different situation was for K, NN and
R birds that had a worst feather condition, whereas,
concerning body lesions, NN and K showed intermedi-
ate results and R the worst. Hence, the frequencies of
FPD and BB resulted dramatically higher in fast-
growing birds when compared with slow-growing
chickens. Indeed, the 60% of fast-growing birds had se-
vere FPD score. The L, A, CL, K, RM and NN birds
showed the higher ROS and TBARs values while R and
G the lower ones (Table 4).
The higher AP was observed in K and NN birds.
Blood a-tocopherol was higher in L, CL and RM sub-
ject, followed by A and G chickens; intermediate values
was observed in NN and K and lower in R chickens.
Regarding native immunity, the lower HCA content
was detected in RM birds, followed by G and R ones
whereas, for lysozyme, K, NN and R had the higher val-
ues. SBA did not show any significant difference in the
different groups.
The heterophils/lymphocytes ratio was higher in R
birds and the lowest values were observed in L, RM
and NN birds. Monocytes and eosinophils were higher
in L, A, CL and G chicks, while concerning HGB, haem-
atocrit and PLT, R birds always showed the lowest val-
ues. RBC did not show significant differences between
groups.
As expected, this distinct kinetic activity associated
with the intake of grass affected the oxidative metab-
olism of the body. The reasons for such trend are
probably related to the activity of birds: on one side
the low activity of fast-growing strain did not produce
a significant oxidative burst, whereas active birds
increased the oxygen demand due to kinetic activity.
Accordingly, plasma ROS and TBARS and AP, that is
the body response to oxidative drive, try to counterbal-
ance such situation by activating a comparable antioxi-
dant response.
Plasma a-tocopherol followed the trend of kinetic
and foraging activity: higher in slow-, intermediate in
medium- and lower in fast-growing birds. Since all the
birds ate the same feed this trend was mostly due to
grass ingestion, which is very rich in vitamin E
(Sossidou et al. 2010). However, in our case, the
Table 3. Effect of poultry genotype on tonic immobility (TI), feather condition and body lesions.
L A CL G RM K NN R Pooled SE
TI Sec. 38
a
25
a
62
b
111
c
48
ab
97
c
62
b
126
c
24.0
Breast – 4.0
c
4.0
c
4.0
c
4.0
c
4.0
c
1.7
a
2.6
b
1.0
a
1.6
Wings – 4.0
b
4.0
b
4.0
b
4.0
b
4.0
b
3.5
a
3.5
a
2.0
a
0.2
Back – 4.0
b
4.0
b
4.0
b
4.0
b
4.0
b
3.8
a
3.8
a
2.0
a
0.1
Tail – 4.0
b
4.0
b
4.0
b
4.0
b
4.0
b
3.7
a
3.7
a
2.0
a
0.2
Vent/cloaca – 4.0
b
4.0
b
4.0
b
4.0
b
4.0
b
3.7
a
3.7
a
2.0
a
0.1
Neck – 4.0
b
4.0
b
4.0
b
4.0
b
4.0
b
3.7
a
4.0
b
2.0
a
0.1
Total score – 24.0
c
24.0
c
24.0
c
24.0
c
24.0
c
20.1
b
21.3
b
11.0
a
5.9
FPD % 0.0
a
0.0
a
0.0
a
0.0
a
0.0
a
30.0
c
20.0
b
60.0
c
20.6
BB % 0.0
a
0.0
a
0.0
a
0.0
a
0.0
a
25.0
b
20.0
b
40.0
c
16.7
N: five birds/four replications per genotype.
L, Leghorn; A, Ancona; CL, crossbreed Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck, R: Ross.
TI, tonic immobility; FPD, footpad lesions; BB: breast blister.
a...c
Values within a row with different superscripts differ significantly at p<0.05.
ITALIAN JOURNAL OF ANIMAL SCIENCE 5
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increase in plasma tocopherol was not able to com-
pletely counteract the production of ROS and the oxi-
dative by-products (TBARs) in very active birds
(Clarkson & Thompson 2000).
The relationship among welfare, immunity and
health has been considered by many authors (Padgett
& Glaser 2003; Broom 2006; Mugnai et al. 2011). The
general question arises whether and how much the se-
lection for productivity affects the ability of an animal
to respond to environmental stressors. Provided that
the activation of the immune system is energetically
expensive, animals would make a trade-off between
production level and immune response. Fast-growing
birds, being genetically programmed for high product-
ivity, might have an impaired ability to make this
trade-off, meaning that they are less capable of coping
with environmental stress. The immune system reflects
the capability to react against external stress (Broom
2006). It is difficult to establish the best immune profile
but we could hypothesise that fast-growing animals,
genetically selected for high production, have difficulty
in adapting to the organic system (Bayyari et al. 1997;
Franciosini et al. 2011). Our results showed that HCA
were higher in slow-growing birds, intermediate in me-
dium- and lower fast-growing birds and in CL. Bayyari
et al. (1997) in turkeys selected for body weight
obtained a similar trend. Further, high HCA levels indi-
cate that the birds have not consumed the comple-
ment for specific immune reactions against various
pathogens (Ricklin et al. 2010).
Medium and fast-growing birds also showed the
higher lysozyme level whereas slow-growing strains
had the lower one indicating a lower presence of
acute and chronic inflammation (Carroll & Martinez
1979). Such trend agrees with Franciosini et al. (2011)
which found a much lower lysozyme value in backyard
turkey.
Concerning blood-related traits, it is widely known
that the stress increases heterophils and reduce lym-
phocytes, so the H/L ratio is an index of response to a
stressor (Maxwell 1990). Slow- and medium-growing
birds showed the lower H/L ratios probably indicating
a higher adaptation to the free-range system. Avian
heterophils act in acute inflammatory response with
highly phagocytic specify and accumulate in inflamed
tissue (Campbell 1995).
Avian leukocytes are only transiently present in the
blood and after this period, they leave the circulation
and migrate into the tissues, where to perform their
specific immune functions (Davison et al. 2008).
Lymphocytes play a key role in protection against
infection and in tumour rejection. Monocytes, hetero-
phils, basophils and eosinophils are categorised as in-
flammatory leukocytes (Davison et al. 2008). Moreover,
eosinophils play a major phagocytes role in the de-
fence against parasites (Glick et al. 1964). Retention of
normal levels of circulating eosinophils is associated
with resistance to stress (Woolaston et al. 1996;
Hohenhaus et al. 1998), and changes in blood eosino-
phils appear as a genotypic or phenotypic hallmark of
stress reactions (Malyshev et al. 1993; Hohenhaus et al.
1998). Their hypothesis is consistent with the present
findings that eosinophilia was exhibited in the L, A and
CL birds, and not in K, NN and R birds. Bush (1991)
pointed out that low percentage of basophils in chick-
ens could also cause poor immunity against disease
and the low percentage may indicate poor health con-
dition. Even if this situation seems to be in opposite
Table 4. Effect of poultry genotype on oxidative status, native immunity and blood parameters.
L A CL G RM K NN R Pooled SE
AP lm HClO ml
1
70.1
a
70.7
a
92.0
a
64.6
a
75.3
a
160.6
b
150.6
b
75.3
a
37.5
ROS mm H
2
O
2
0.24
b
0.19
ab
0.19
ab
0.07
a
0.18
ab
0.26
b
0.23
b
0.12
a
0.05
TBARS lg/ml 1.58
c
1.49
bc
1.59
c
1.38
b
1.56
c
1.46
bc
1.45
bc
1.24
a
0.18
a-tocopherol ‘‘ 5.03
cd
4.84
c
5.54
d
4.38
c
5.90
d
2.69
b
2.85
b
0.74
a
0.36
HCA
1
CH
50
81.86
c
84.64
c
78.45
c
68.88
b
59.35
a
78.08
c
81.47
c
69.17
b
6.54
SBA
2
% 70.82 68.89 71.97 66.93 72.02 73.05 68.35 65.29 7.21
Lysozyme lg/ml 1.50
a
1.47
a
2.00
a
1.83
a
1.42
a
6.80
b
6.07
b
6.89
b
1.59
Heterophils (H) % 44.75
a
47.07
ab
50.80
b
50.57
b
40.34
a
48.94a
bc
45.71
ab
56.61
c
3.24
Lymphocytes (L) ‘‘ 50.50
b
46.89
ab
44.67
a
44.98
a
56.11
c
48.14
ab
51.33
b
40.60
a
5.14
H/L – 0.89
a
1.00
b
1.14
bc
1.13
bc
0.73
a
1.01
b
0.91
a
1.39
c
0.36
Monocytes % 2.43
c
2.22
bc
1.80
b
1.75
b
1.00
a
1.06
a
1.64
b
1.40
a
0.29
Eosinophils ‘‘ 2.38
b
2.80
b
2.50
b
2.05
b
1.95
b
0.86
a
0.89
a
0.80
a
1.24
Basophils ‘‘ 0.38 0.19 0.48 0.65 0.60 0.86 0.32 0.38 0.22
RBC
3
10
6
/ml
1
2.94 3.53 3.25 2.49 2.90 2.61 2.57 2.89 0.82
Hb
4
g/dl
1
21.48
b
22.14
b
19.70
b
17.58
a
19.68
b
18.17
a
17.64
a
17.48
a
2.16
Ht
5
% 37.49
bc
40.93
c
35.83
b
32.14
b
35.87
b
34.16
b
32.37
a
28.72
a
2.73
PLT
6
‘‘ 5.50
ab
7.78
c
5.63
ab
4.53
a
5.27
ab
6.35
b
5.57
ab
4.13
a
1.92
N: five birds/four replications per genotype.
L, Leghorn; A, Ancona; CL, crossbreed Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck, R, Ross.
1
Haemolytic complement assay;
2
serum bactericidal activity;
3
red blood cells;
4
haemoglobin;
5
haematocrit;
6
platelets.
a...d
Values within a row with different superscripts differ significantly at p<0.05.
6 C. CASTELLINI ET AL.
Downloaded by [95.250.45.19] at 10:57 25 February 2016
with all till now affirmed, a possible explanation could
be the strong age-related haematologic profile
observed in broiler strains (Talebi et al. 2005), in differ-
ent breeds of chickens (Islam et al. 2004), in young
cocks (Kral & Suchy 2000) and in pigeons (Seiser et al.
2000).
Monocytes constitute approximately 5–10% of per-
ipheral blood lymphocyte, but this number varies in
different chicken lines (Gordon & Taylor 2005). Besides
modulating the immune response to pathogenic infec-
tions by producing proinflammatory cytokines, another
important function of monocytes is their ability to give
rise to tissue macrophages (Auffray et al. 2009). Heat
stress (Altan et al. 2000) or transport (Ajakaiye et al.
2010) reduced monocyte.
The changes here observed in haemocrome, HGB,
haematocrit are probably linked to the previously
described distinctive level of activity done by birds. It
is widely known that exercise enhances [Hb] and VO
2
max that is also proportional to the increase in the
oxygen carrying capacity of blood (Calbet et al. 2006).
The higher level of Ht in slow-growing birds may en-
hance oxygen delivery to the tissue. Also, this
increment is supposed to be a factor for enhanced
RBC as a reaction to increase body oxygen require-
ment. Julian and Mirsalimi (1992) also found that the
oxygen saturation was higher in slow-growing chickens
(91.6%) than in fast-growing chickens (86.0%).
According to this, besides an obvious genotype effect
on the behaviour and native immune parameters, less
productive birds, if requested to enhance their natural
defence (L, A and CL) seem to be better adapted,
probably due to higher physiological homeostasis.
The standardised score of adaptability index is
shown in Table 5. The worst adaptability index was
shown by R chicks followed by K and G chickens. The
L, A, CL and RM chicks showed the best adaptability to
an organic system. A strict negative relationship be-
tween adaptability and daily weight gain is shown in
Figure 1; however, within the same subclass (fast-, me-
dium- and slow-growing) such strict relation disap-
peared (Figure 2).
As expected, R birds reached the highest slaughter
weight (4400 g), K, NN and RM the intermediate (2380,
2500 and 2161 g, respectively), followed by CL and G
(1865 and 2018 g, respectively), and slow-growing birds
Table 5. Adaptability indexes of different poultry genotype.
L A CL G RM K NN R Pooled SE
Adaptability 0.49
d
0.50
d
0.58
d
0.41
b
0.94
c
0.56
b
0.18
c
1.77
a
0.50
Slow-growing Medium-growing Fast-growing
Mean and SD 0.5360.41 0.05 60.90 1.77 60.48
N: five birds/four replications per genotype.
L, Leghorn; A, Ancona; CL, crossbreed Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck, R, Ross.
(slow – 0, GR <24 g/d; medium – 1 (25 <GR <40 g/d and fast – 2 growing, GR >40 g/d).
a...d
Values within a row with different superscripts differ significantly at p<0.05.
A
A
A
A
A
A
A
A
A
AA
A
A
A
A
A
A
A
A
A
NN NN
NN
NN
NN
NN
NN NN
NN
NN
NN
NN
NN
NN
NN
NN
NN
NN
NN
NN
G
G
G
G
G
GG
G
G
G
G
G
G
G
G
G
G
G
G
G
LC
LC
LC LCLC
LC
LC
LC
LC
LC LC
LC
LC
LC
LC
LC
LC
LC
LC
LC
K
K
K
K
K
K
K
K
K
KK
K
K
K
KK
K
K
K
K
L
L
L
L
L
L
L L
L
L
L
L
L
L
L
L
L
L
L
L
RM
RM
RM
RM
RM RM
RMRM
RM
RM
RM
RM
RM
RM
RM
RM
RM
RM
RM
RM
R
R
R
R
R
R
R
R
R
R
R
R
R
RRR
R
R
R
R
−3
−2
−1
0
1
2
10 20 30 40 50 60
daily gain (g/d)
Figure 1. Fitted values of adaptability score versus daily gain (95% upper and lower limits). L, Leghorn; A, Ancona; CL, crossbreed
Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck, R, Ross.
ITALIAN JOURNAL OF ANIMAL SCIENCE 7
Downloaded by [95.250.45.19] at 10:57 25 February 2016
(A 1370 and L 1320 g) (Table 6). Consequently, all the
other productive traits (feed intake, daily weight gain)
followed this trend, whereas feed to gain ratio
increased in slow-growing birds.
Concerning mortality and culling rate, R chickens
showed the highest values, whereas the A and L ones
showed the lower value of culling rate. To the best of
our knowledge, this is the first paper which analyses
the adaptation of different poultry strains to the organ-
ic rearing system using a wide panel of physiological
and behavioural traits. The relevance of such paper is
related to the disposal of specific range for the poultry
strains herein analysed but mainly for the definition of
a synthetic index which assesses the adaptability to
the organic free-range system. Such index is strictly
connected with the daily gain of the birds: daily
weight gain higher than 50 g/d resulted in very low
values and these strains should be avoided in an or-
ganic system. Medium- and mainly slow-growing birds
showed the highest adaptation. However, within the
same sub-category (slow, medium and fast), the index
showed a wide variability and the adaptation seems
mostly independent from daily weight gains (e.g. NN
has a higher daily gain than K while having a higher
adaptation index). Thus, the daily weight gain is essen-
tial for the exclusion of extremely productive strains
but it is not adequate for defining the adaptability of
birds to an organic system.
Naturally, other data are involved in the choosing of
a strain mainly related to the economic sustainability
(e.g. feed to gain index). For example, the body weight
of L and A chickens at 81 d was less than 2 kg, which
is the under the minimum weight for the market
(Saveur 1997), whereas the medium-growth chickens
ranged from 2 to 2.5 kg.
Conclusions
This study confirms that the slow-growing chickens
show better welfare status and adaptability to the or-
ganic system followed by medium-growing ones. Fast-
growing chickens, although have the best productive
performance, appeared no adapted to the outdoor en-
vironment as demonstrated by the high number of
culled birds and mortality.
However, the definition of strains adapted to the or-
ganic system requires the measure of a wide panel of
physiological and behavioural traits and not only daily
weight gain. A multi-criteria analysis should be devel-
oped considering the economic, ecological, social and
qualitative performance of different poultry genotypes
Table 6. Productive performance of different poultry genotypes.
L A CL G RM K NN R Pooled SE/
(*)
X
2
Live weight g 1320
a
1370
a
1865
ab
2018
b
2161
bc
2380
c
2500
c
4400
c
120
Feed intake g/d 78.3
a
80.6
a
89.7
a
87.7
a
97.7
ab
103.3
b
101.8
b
162.3
c
19.2
Daily weight gain ‘‘ 16.1
a
16.9
a
22.8
b
25.0
bc
26.7
bc
29.2
c
30.7
c
54.5
d
0.09
Feed:gain ratio 4.8
b
4.7
b
3.9
b
3.4
ab
3.9
b
3.4
ab
3.2
ab
3.0
a
0.28
Culled birds % 0
a
0
a
2
b
2
b
2
b
3
b
2
b
5
c
24
(*)
Mortality ‘‘ 4
a
3
a
4
a
3
a
4
a
6
a
5
a
14
b
32
(*)
N: 25 birds/four replications per genotype.
L, Leghorn; A, Ancona; CL, crossbreed Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck, R, Ross.
a...d
Values within a row with different superscripts differ significantly at p<0.05. *: X
2
P<0.05.
Figure 2. Fitted values of adaptability score versus daily gain within sub-groups. L, Leghorn; A, Ancona; CL, crossbreed
Cornish Leghorn; G, Gaina; RM, Robusta Maculata; K, Kabir; NN, Nacked Neck; R, Ross.
8 C. CASTELLINI ET AL.
Downloaded by [95.250.45.19] at 10:57 25 February 2016
for identifying which of them better fit with the organ-
ic system requirements.
Only small national projects study these aspects of
adaptability particularly in heat stress conditions typical
of the Mediterranean area and commercial breeding
companies do not seem interested in selecting suitable
strains for these production systems. At the end, the
problem remains unsolved with negative repercussion
on the chicken organic production system as well as
on the consumer perceptions towards its products
quality traits.
Acknowledgements
The authors wish to thank Giovanni Migni and Osvaldo
Mandoloni for technical assistance. The research was partially
supported by Agricultural Research Council (CRA), Ministry of
Agricultural, Food and Forestry Policies, Italy.
Disclosure statement
The authors report no conflicts of interest. The authors alone
are responsible for the content and writing of this article.
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