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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 Summary 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. Summary 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 Summary 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. Summary 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. Summary 150 • 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. Summary 151 • 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. Summary 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 |