INTRODUCTION
The chicken is a domesticated fowl that is believed to be descended from the
wild Indian Jungle Fowl and South East Asia Red Jungle Fowl (Moiseyeva
et al., 2003). It is one of the most common and wide-spread domestic
animals with a population of more than 24 billion in 2003 and kept primarily
as a source of food from both their meat and eggs.
There are many strains and breeds of chicken with different carcass characteristics
such as broilers (Gallus domesticus), indigenous chicken (Gallus gallus
domesticus) and jungle fowl (Gallus gallus). Broilers are very similar
as the ancient jungle fowl, except it lays on muscle faster. Modern broilers
are typically a third generation offspring (an F2 hybrid) and are fed with high
quality formulated diet to increase muscle growth hence increase the body weight,
while the jungle fowl, which is known to be the ancestor of all the domestic
fowl, is considered as omnivorous (Klasing, 2005; Arshad
et al., 2000). Their diet consists of arthropods together with tender
leaves/shoots, seeds as well as fruits of numerous plant species. As for the
indigenous chicken or ayam kampung (refers to the present Malaysian village
chicken) are crossbred between red Jungle Fowl and mixed exotic domestic breed
that has been brought by the Europeans, mainly British (Duguma,
2006). Feeding routine of this chicken are usually once or twice a day,
with variety of left over food such as rice or used coconut pulp. The chickens
are free roaming and studies have showed that rearing indigenous chicken is
cost effective since very little financial input is needed (Ramlah,
1996).
Indigenous chicken and jungle fowl are always thought to be good in term of
carcass composition compared to the broilers due to its low fat content. However,
there is no quantitative information available to support the statement. To
the best of our knowledge, no published information on the carcass evaluation
of jungle fowl or indigenous chicken is available. Therefore, this study was
carried out to evaluate the carcass composition and various tissue components
of jungle fowl, broiler chicken and indigenous chicken.
|
| Fig. 1: |
The carcass was dissected into (a) forequarter and (b) hind
quarter. The forequarter was further divided into (a1) breast, (a2) ribs
and (a3) wing. The hind quarter were divided into (b1) right and left leg
including the pelvis |
MATERIALS AND METHODS
A total of 35 birds were used in this study consisting of 15 adult broiler chicken (8 female and 7 males), 10 adult free range indigenous chicken (8 female, 2 male) and 10 adult jungle fowl (2 female, 8 male). The broiler chicken was purchased from a supplier in Malaysia, while the free range chicken and the jungle fowl was caught from a small village in Dengkil and from the wild, respectively (by wildlife research team, Faculty of Veterinary Medicine, UPM-approved by the Wildlife ethics in the faculty). The study was conducted at the Faculty of Veterinary Medicine, University Putra Malaysia from 16th April 2007 to May 2008.
All birds were fasted for approximately 24 h before cervical dislocation and
the live weight were recorded. Later all carcasses were frozen 24 h at 0°C.
Prior to dissection, the carcasses were thawed and then separated according
to different meat composition. First the carcass was de-feathered and dissected
into two equal portions. The carcass was further divided into forequarter and
hindquarter by cutting posterior to and parallel to the rib cage, posterior
to the last thoracic vertebrae, last ribs and the sternum (Fig.
1a, b). The pelvis and legs makes the hindquarter (Fig.
1b). The forequarter was cut into two halves consisting of the right and
left breast, wings and ribs, where as the hindquarter was divided into two equal
portions consisting of the right and left legs including the pelvis (Fig.
1).
All the internal organs were weighed separately and the results were recorded. The skin, muscles, fat as well as the bones and connective tissue of each portion were also weighed and recorded.
Statistical analysis was done by using Analysis of Variance test (ANOVA).
RESULTS
The results are divided into mean live weight, mean ribs weight, mean of hind quarter weight, mean breast weight and mean wing weight.
Mean Live Weight
Mean live weight of adult broiler chicken was higher (2184.08 g) compared
to adult indigenous chicken (1384.59 g), whereas jungle fowl has the lowest
mean live weight (729.39 g) (Table 1).
Mean of Rib Weight
Among the three breeds of chicken studied the jungle fowl had the highest
rib weight (74.3±18.05) followed by the broilers (47.70±1.55
g) and indigenous chicken (29.0±1.76 g). The highest bone weight for
this region was obtained from the jungle fowl, whereas the indigenous chicken
had the least bone weight.
| Table 1: |
Means of total body weight among three breeds of chicken |
 |
| Table 2: |
Means of ribs trait among three breeds of chicken |
 |
| Mean values with different superscript between the column
are significantly different (p<0.05). Data are expressed as Mean±SE |
| Table 3: |
Means of hind quarter trait among three breeds of chicken |
 |
| Mean values with different superscript between the column
are significantly different (p<0.05). Data are expressed as Mean±SE |
As for the muscle content, the broiler had significantly more muscle content
compared to indigenous chicken and jungle fowl (Table 2).
Highest fat content in the ribs was found in the indigenous chicken followed
by the broiler and jungle fowl. These results show that the muscle to bone ratio
is higher in broiler compared to indigenous chicken and jungle fowl. Broiler
on the other hand contains more meat in the ribs compared to indigenous chicken
and jungle fowl. The jungle fowl had the least muscle to bone ratio (Table
2).
Mean of Hindquarter Weight
The hind quarters whole weight is significantly higher in broiler (359.4±5.84
g) compared to indigenous chicken (218.9±15.98 g) or the jungle fowl
(108.4±5.43 g). The bone of jungle fowl was again significantly higher
with least muscle content (Table 3). Broiler has the highest
muscle weight and high amount of fat. But the indigenous chicken has high muscle:
bone ratio (3.4±0.08) compared to broiler (2.9±0.08). Jungle
fowl has the lowest muscle: bone ratio (0.10±0.00). These results show
that indigenous chicken has more muscle in this region compared to the other
two breeds (Table 3).
Mean of Breast Weight
The whole weight of breast is significantly higher in broiler (281.9±6.25
g) compared to jungle fowl (160.9±13.15 g) and indigenous chicken (118.8±4.81
g). However, the weight of the bone in this region is significantly higher in
jungle fowl compared to the other two breeds. Broiler has a significantly higher
breast muscle weight and fat content (Table 4). The least
muscle weight and fat content is found in the jungle fowl.
Mean of Wing Weight
Whole weight of wing of the broiler (82.4±1.36 g) is higher compared
to indigenous chicken (46.9±1.26 g) and jungle fowl (35.3±1.53
g). The bone of broiler is significantly heavier. Apart from this, broiler had
the highest muscle weight.
| Table 4: |
Means of breast trait among three breeds of chicken |
 |
| Mean values with different superscript between the column
are significantly different (p<0.05). Data are expressed as Mean±SE |
| Table 5: |
Means of wing trait among three breeds of chicken |
 |
| Mean values with different superscript between the column
are significantly different (p<0.05). Data are expressed as Mean±SE |
Broilers fat content in this region is significantly higher compared to indigenous
chicken and jungle fowl. Thus the meat:bone ratio of wing is higher in indigenous
chicken compared to broiler and jungle fowl (Table 5).
DISCUSSION
The results from this study showed that broiler has significantly higher whole
weight and muscle weight compared to the indigenous chicken and jungle fowl.
This is due to the genetic improvement and selection to get a desired trait.
The domestication of wild jungle fowl marked the start of selective breeding
of poultry and by the end of the nineteenth century many breeds were in existence.
These showed marked differences between breeds and homogeneity within them for
a range of traits, including production traits such as body size and musculature.
Some of the poultry breeds were the basis of industrial poultry breeding (Van
Kaam et al., 1998) and this has lead to a tremendous development
of poultry industry. Many studies are done to get a chicken that can reach market
weight in a short period of time like the broilers, without realizing the importance
of the meat quality. Besides that, more emphasize is given on the feeds, where
high quality feeds are being produced to optimize the growth rate but not the
meat quality. Genetic selection together with high quality diet, increase the
broilers body weight. However, excessive energy intake leads to increasing fat
deposition in the body (Moravej et al., 2006).
This supports present data where significantly higher fat weight was found in
broilers in all regions studied except the rib region. Jungle fowl was found
to content the least fat in all the regions studied. However, jungle fowl also
had the least muscle weight and significantly higher bone weight, bringing the
muscle: bone ratio in this bird to be very poor. This is due to the influence
of the feed and their habitat. In another study conducted by Kamran
et al. (2008), feeding broilers with low crude protein diets with
constant metabolic energy:crude protein ratio has affected the growth performance
but not the carcass parameters. However, in the present study, the broilers
that are used were fed with commercial diet containing high crude protein and
therefore, affecting the meat composition in particular the fat conent. The
jungle fowl and village chicken had good carcass parameters as in the study
by Kamran et al. (2008). However, the growth
parameters were not measured in this study.
To our knowledge there are no studies done on the carcass composition of jungle fowl, since it belongs to a protected wild life species. Jungle fowl’s diet consists mainly of insects (ants, beetles, termites and flies), crustaceans (leeches, snails) and also plants as well as fruits. These are good sources of proteins and will be utilized efficiently by the jungle fowl. Unlike the broilers, jungle fowl need to travel a long distance to feed and during this process, high energy is used. Instead, the broilers are fed with highly formulated feed and not much energy is used in finding their food. Therefore, this will increase their body weight and also the fat content since the energy that is taken up are not being utilized efficiently as the jungle fowl, but stored in muscles as fat.
The carcass composition of the indigenous chicken on the other hand, mainly
their muscle weight, bone weight, fat weight and muscle:bone ratio in all the
various parts were higher than the jungle fowl but lower than the broilers.
The diet of indigenous chicken consists mainly of kitchen left over, such as
rice or used coconut pulp (Ramlah, 1996). Apart from
these diets, other cheap and easily available food materials in the village,
such as sago trunks and banana trunks are also fed to these chickens. They are
fed once or twice a day and as for the rest of the day, they will find their
own food which includes insects, plants, grass, fruits and earthworms. This
explains why indigenous chicken has low fat and muscle weight compared to broilers
as they need to use energy to find food.
As for the bone weight, despite having pneumatic bones, jungle fowl has significantly higher bone weight. This is again due to their diet which help to build stronger bones, as their diet contain very high level of calcium compared to the broilers diet.
The present study on the carcass composition of the three birds showed that the carcass composition of indigenous chicken is always in between the broiler and jungle fowl due to its similar habitat and feeding behaviour as the other two breeds of chicken. Indigenous chicken carcass composition will be the best to be consumed as it is healthy with medium level of fat, muscle and bone. Even though broilers have the highest muscle composition, but its fat level is also significantly high and can be a risk factor to many diseases, such as heart disease and diabetes in human. Therefore, the food and meat industry should focus on other aspect of feed in order to get good quality meat composition in poultry.
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