الفهرس 
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Abstract
Summary
Using different cooking methods for the infected chicken
meat with some diseases and its effect on mice
Chicken meat is considered one of the most popular protein foods
overall the world due to it’s relatively cheap, and their specific sensory
attributes as well as increasing tendency of the public to consider white
meat as being healthier compared to red meat. Chicken is exposed during
the period of her life for many infectious diseases, including bacterial
diseases that can be transmitted through food and cause food infection to
humans. Salmonellosis and colibacillosis were considered the major
bacterial diseases in the poultry industry worldwide.
Thus, the object of this study was to clarify the following:
Effect of bacterial infection diseases on nutritional value and
physical properties of chicken meat comparing to that of healthy
chicken meat.
Effect of feeding on different cooking methods for chicken meat
on their microbial content and nutritional value comparing to that
of healthy chicken meat.
Effect of feeding on different cooked chicken meat (healthy /
infected before cooking) on experimental rat’s body weight and
relative organs weights (liver, kidney and heart).
Effect of feeding on different cooked chicken meat (healthy /
infected before cooking) on liver function, lipids profile and
kidney function of experimental rats.
Histopathological changes that might occur on internal organs of
experimental rats after feeding on different cooked chicken meat.
The current study was conducted on 75 broiler chickens (Sasso)
aged 40 days old were obtained from Qena’s Governorate poultry
wholesale in April 2013. Chickens were classified randomly into 3
groups (each of 25 chickens) and kept in 3 separated rooms. The first
group was healthy group that represented the control group, the second
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146
group was infected with Salmonella enteritidis, and the third group was
infected with E. coli O78. All chickens were fed Al Asema Feeds for 15
days. After two weeks of infection chickens were slaughtered at the same
age to the comparable experimental conditions and different
investigations were carried out on it.
The chickens were cooked using four different cooking methods
(boiling, Braising, roasting, and frying). After cooking, each of cooked
samples was examined bacteriologically to investigate the presence of
microbes (Salmonella / E. coli)
78 Female White Albino rats (Sprague Dawley strain) initially
weighing 60 - 80g were obtained from International Research Center,
Dokky, Cairo, Egypt. Rats were housed individually in wire cages under
the normal laboratory conditions and fed the basal diet for a week as
adaptation period. Body weight gain and feed intake were calculated
through and by the end of the experiments. Rats were divided into 13
groups each group contained (6 rats) as following: Group (1): Control
group fed basal diet and groups from group (2) to group (13) were fed
diet contained different cooked chicken meat.
The obtained results showed that:
Firstly: The results about weights of chickens during the
experiment:
• There were significant differences between the healthy group and
both of salmonellosis and E. coli chickens in weights after one and
two weeks. Decreasing the percentage of weights in salmonellosis
and E. coli chickens than that in healthy chickens might be due to the
droping of feed intakes daily.
• The statistical analysis showed that there were significant differences
between the salmonellosis group and both of healthy and E. coli
chickens in liver weights (p<0.05). While, there were no significant
differences between the salmonellosis group and both of healthy and
E. coli chickens in heart and gizzard weights.
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147
Secondly: The results about effect of different cooking
methods on microbial content of chicken meat:
• Salmonella were isolated from raw chicken meat and organs (liver,
heart and gizzard) before cooking. The mean values of Salmonella
count in meat were 1.9×104, 2.7×105, 3.7×104 and 5.9×104 CFU/g;
respectively.
• Salmonella was not isolated from any cooked samples. These data
mean that Salmonella were destroyed by cooking temperature.
• E. coli were isolated from raw meat, livers, hearts and gizzards
samples that cultured in Eosine Methylene blue agar after
enrichment on Tryptic soya broth, with mean values 3.8×106,
1.6×107, 5.2×106 and 2.7×106 CFU/g; respectively.
• E. coli were not detected in boiled and roasted samples, while such
bacteria were isolated from braised livers and fried samples. the
mean values of E. coli count in braised liver samples were 1.1×103
CFU/g, whilst the mean values of fried meat, livers, hearts and
gizzards samples were 1.3×104, 1.1×103, 1×103 and 1.2×104 CFU/g;
respectively
• E. coli were isolated from raw chicken meat, livers, hearts and
gizzards samples by culture in MacConkey agar with mean values
4.1×104, 1.8×105, 4.5×104 and 2.9×104; respectively. After cooking
all samples were free from E. coli and E. coli was not isolated from
any cooked samples.
Thirdly: The results about Chemical composition of
chicken’s meat:
Effect of infection by Salmonella enteritidis and E. coli O78 on
physico-chemical composition of broiler chicken meat:
• Results indicated that the proximate chemical composition was
varied between healthy chicken meat and infected chicken meat with
Salmonella and E. coli. Moisture values content of raw healthy
chicken meat had an intermediate values salmonellosis samples
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148
which recorded the highest value and E. coli chicken meat that
recorded the least.
• The highest mean values of fat were scored in chicken meat infected
by E. coli 12.58 followed by that in Salmonellosis chicken 9.26 and
that in healthy ones 7.95.
• As a result of infection with Salmonella and E. coli, their meat
protein contents were decreased than that in healthy ones.
• Ash content of raw E. coli chicken samples was lower than that of
previous samples. Significant differences in total ash content were
found between raw E. coli chicken samples and other samples.
• Chicken meat had low level of carbohydrate, the mean values of
carbohydrates of raw healthy and salmonellosis chicken meat were
similar and no significant differences were found between them.
While, the mean values of carbohydrates of raw E. coli chicken
samples were low. Significant differences in total carbohydrates
content were found between raw E. coli chicken samplers and other
samples.
• The energy that could be obtained from raw E. coli chicken samples
was higher than that obtained from raw and salmonellosis ones.
• Mean values of pH for raw healthy chicken meat were 5.27, while
that for Salmonellosis and E. coli were 5.97 and 6.08; respectively.
Effect of cooking methods on physico-chemical composition of
broiler chicken meat:
• Results showed that cooking methods had a great influence on the
chemical composition of chicken’s meat. Whereas, low moisture
content in cooked samples than that in the raw samples led to
changes of other solid constituents.
• Decreasing moisture led to high fat content in the samples after
cooking while the protein and ash content in cooked samples were
decreased.
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149
• The statistical analysis reflected that there was a high statistically
significant negative correlation existing between fat and both
moisture and protein contents in the studied chicken muscles at the
0.01 level. As it referred that there was a high statistically
significant correlation existing between moisture and protein
contents in muscles.
• Caloric values increased after cooking in all samples than that in
raw samples, the highest caloric values were found in fried samples
that might be due to its high fat and carbohydrate content.
• The highest cooking loss occurred in roasted samples which had
low level of fat, while frying method that had the highest level of
fat content, caused the lowest rate of cooking losses. Cooking
losses tended to be linear with time and with an increasing final
temperature.
Effect of infection by Salmonella enteritidis and E. coli O78 on
amino acids content in broiler chicken meat:
• Presence of glycine amino acid only in infected chicken meat with
salmonella and E. coli might be due to synthesis process during
infection.
• Results showed that cooking methods had varied influence on amino
acids concentration. Amino acids content was affected by different
cooking methods. Although most amino acids decreased after using
cooking methods, glutamic acid, alanine, leucine, tyrosine and
phenylalanine were increased after brasing, frying and roasting.
Effect of infection by Salmonella enteritidis and E. coli O78 &
cooking methods on minerals content in broiler chicken meat:
• Mineral concentrations had high variations among the three different
raw samples. Healthy raw samples scored the highest concentration
of Fe, K and Zn, salmonellosis raw samples recorded the highest
concentration of P and Na, while E. coli infected raw samples had
the highest concentration in Ca.
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• Cooking methods seemed to affect the various minerals in different
ways. Boiling enhanced the concentrations of Fe and Zn than that in
raw samples, Zn and K concentrations were increased after braising
methods, Ca and K concentrations were increased after roasting
methods, while chlorine was detected only in fried samples.
Fourthly: The results about effect of feeding different
cooked chicken meat on experimental rats:
• Results reflected that although there were no significant differences
among all groups all over the experiment in body weight, there were
significant differences among the groups in the change of weight
throughout the experiment, body weight gain and rate of growth at
(P<0.05). Rats which fed on fried samples had the highest body
weight gain comparing with other groups followed by groups fed
roasted samples.
• The results revealed that FI showed significant differences among
groups all over the experiment period at (P<0.05). Food intake from
fried and roasted samples had increased significantly throughout the
experiment which might be due to their specific sensory attributes
and acceptable taste, consequently this is what led to an increase in
body weights gain of rats fed on these samples.
• The highly significant increase in mean and relative weight of liver
and heart recorded in all groups fed diet containing fried samples
followed by groups fed diets containing roasted samples, groups fed
diet containing boiled samples and groups fed diet containing braised
samples. Results revealed that the mean values of kidney weights
showed significant differences among all studied groups at (P<0.05),
while relative weight of kidney showed that there were no significant
differences among groups.
• Results showed that there were significant differences among groups
in blood serum lipids (cholesterol, triglycerides, VLDL-c and LDLc),
while there were no significant differences in the HDL-c among
groups.
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• Results noted that rats groups fed diet containing fried and roasted
chicken meat had the highest levels of lipids serum (cholesterol,
triglycerides, VLDL-c and LDL-c), while they had lowest levels of
HDL-c. On the contrary, rats groups fed diet containing boiled and
braised chicken meat had the highest levels of HDL-c, while they
had the lowest levels of (cholesterol, triglycerides, VLDL-c and
LDL-c)
• Results summarized that rats groups fed diet containing fried and
roasted chicken meat had the highest levels of ALT and AST. While
both boiling and braising methods of chicken meat had healthier
effect than frying and roasting methods, that due to their relatively
impact- reducing of liver function. As well as results pointed that
significantly highly decrease of ALT level at (P<0.01) for control
group fed basal diet had been recorded compared to all groups fed
diet containing cooked chicken meat samples.
• The statistical analysis reflected that there were significant
differences among groups in serum urea, creatinine and uric acid.
Boiling and braising were better than frying and roasting, for their
healthier effects about kidney function whereas they scored the
lowest levels of serum urea, creatinine and uric acid.
Fifthly: The results about histopathological studies:
The histopathological results confirmed the previous results about
effect of feeding by different cooked chicken meat on experimental rats’
organs as following:
• Liver section of rats fed boiled chicken samples showed almost
normal appearance. As well as liver section of rats fed braised
samples showed minimal insignificant changes. On the other hand,
rats groups fed on fried or roasted chicken samples pointed out
histopathological changes in liver tissues such as severe
inflammatory reaction in the portal tract in the liver and and
granulomatous reaction within the liver lobues.
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152
• Rat groups fed on boiled or braised chicken samples had section of
cardiac muscle characterized with minimal insignificant changes.
While, hearts sections of rats fed fried or roasted chicken samples
had severe histopathological changes.
• Rats groups fed on boiled, braised or fried chicken samples had
normal appearance of the kidney sections. However, kidneys of rats
fed on roasted chicken samples showed histopathological changes