الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Two native strains namely Matrouh (MA) and Inshas (IN) were used in a crossbreeding experiment. This experiment was carried out in the Poultry Breeding Farm at Moshtohor, Benha University, Egypt during the period from April 2005 to June 2005. A total number of 480 chicks (produced from four genetic groups, two purebred strains and their reciprocal crosses) were chosen randomly to study the effects of genetic groups, probiotic and prebiotic and sex on growth, feeding and microbiological and immunological traits. Crossbreeding effects (direct additive, maternal additive and heterosis) were also estimated. The studied traits were body weight (BW) at 1st , , 3rd , 4th, 5th, 6th , 7th, 8th, 9th and 10th week of age; daily gain (DG) during the intervals from 1-4, 4-8, 8-10 and 1-10 weeks fo age; livability (L) during the intervals of 1, 2, 3 and 4 weeks of age; feed intake (F1) and feed conversion (FC) at 1st , 2nd , 3”1, 4th, 5th, 6th , 7th, 8th, 9th and 10th week of age; and Salmonella colonization, caecal pH and antibody titer at 4th week of age.
Results obtained in this study could be summarized as follows:
1-Genetic group effect was significant on BW, DG, salmonella colonization, and antibody titer traits, but not significant on livability, most feed intake and feed conversion, and caecal pH traits.
2-MA strain expressed significantly (P.S0.05) heavier BW, DG than IN strain for most traits at different ages. Means of BW traits ranged from 200.30 to 744.38 g in MA and from 191.58 to 629.64 g in IN. Means of DG were ranged from 6.26 to 18.15 g in MA and from 5.84 to 14.19 g in IN.
3-Means of BW in INxMA cross were significantly (P<0.05) heavier than reciprocal one at 1st, 2nd, rd and 4th weeks of age, but not significant for BW at other ages.
4-Effects of probiotic and prebiotic were significant (Pfc0.05 or P<0.001) on most feed conversion, but not significant on livability and feed intake traits at most ages.
5-Feed intake was significantly higher (P<0.05) in IN purebred strain than in MA strain at 1st week of age (3.52 vs. 2.81 g), while it was higher (P<0.05) in MA than IN at 4th week (28.26 vs. 25.69 g) and at 6th week (39.62 vs. 35.14 g). There were no significant effect between MA x IN and IN x MA crossbreds for feed intake traits.
6-Means of feed conversion was significantly better (P<0.05) in MA strain than in IN strain at 5th week of age (6.46 vs. 11.75 g feed/g gain), 6th week (3.34 vs. 4.82 g feed/g gain), at 7°1 week of age (4.58 vs. 6.31 g feed/g gain) and 10th week of age (2.88 vs. 3.85 g’ feed/g gain), while there were no significant differences between them for other ages.
7-Means of BW and DG for chicks treated with Enterococcus faecalis (treatment No. 9) were the heaviest, followed by those treated with Bacillus subtilis (treatment No. 10) compared to the control group (treatment No. 6).
8-Effect of sex on BW, DG and livability traits was highly significant (P<0.001), while it was not significant on most feed conversion traits. Males were almost heavier than females at different ages.
9-Means of Salmonella colonization showed no significant differences between MA and IN purebreds at 4th week of age, in spite of, MA purebred had highly resistant (lowest Salmonella colonization, 10°47 cfu) compared to IN purebred (susceptible, 10°7° cfii). INxMA cross had significantly decreased Salmonella colonization (10°40 cfii) at 4th week of age compared to MAxIN cross (100.64 cfu).
10-All probiotic and prebiotic treatments significantly decreased Salmonella colonization in caecum and caecal pH (P<0.001) of chicks at 4th week of age compared to the control group, except for chicks’ treated with 2.5% lactose alone in drinking water (treatment No.1). Chicks’ treated with
2.5% lactose and Lactobacillus acidophilus (treatment No. 2) recorded the lowest value of caeca] pH (6.04).
11-There were no significant differences between MA and IN on immunity against Salmonella at 4’h week was observed. For crossbreds, INxMA crossbred had significantly (P<0.05) higher immunity against Salmonella at 4`h week of age than average of two purebreds.
12-The highest antibody titer was recorded for the group treated with Enterococcus faecalis (treatment No. 9), followed by the group treated with 2.5% lactose (treatment No. 1).
13-Estimates of direct additive of gene (GI) were positive for all BW and DG, most feed intake and feed conversion, salmonella colonization and antibody titer traits, but negative for caecal pH. This effect was insignificant for most of these traits, but significant only for Salmonella count.
14-The percentages of GI ranged from 2.22 to 9.26 for BW; 8.43 to 10.42 for Do; -5.65 to 5.66 for feed intake and -51.45 to 92.26 for feed conversion. Estimates of GI were 12.12% for salmonella colonization, - 1.11% for caecal pH and 6.32% for antibody titer.
15-Estimates of maternal additive (GM) were positive for most DG; most feed intake and feed conversion; and caecal pH traits, but negative for most BW, Salmonella colonization and antibody titer. This effect was insignificant for most of these traits, but significant for some BW traits and Salmonella colonization.
16-The percentage of Gm ranged from -5.76 to 0.60 for BW; -4.96 to 1.82
for DG; -5.57 to 3.38 for feed intake and -10.92 to 34.08 for feed
conversion . Estimates of GM were -18.18% for salmonella colonization,
0.29% for caecal pH and -7.69% for antibody titer.
17-Estimates of heterosis (HI) were positive for all DG; most BW, feed intake, feed conversion; caecal pH and antibody titer traits, but negative for Salmonella colonization. This effect was insignificant for most of
these traits, but significant only for Salmonella colonization and antibody titer traits.
18-The percentage of HI ranged from -5.24 to 9.05 for BW; 0.50 to 11.29 for DG; -0.95 to 6.36 for feed intake and -56.81 to 23.47 for feed conversion. Estimates of H’ were -21.21% for Salmonella colonization, 0.37% for caecal pH and 25.17% for antibody titer that produce healthy final product for consumers to save human health.
19-Using of Enterococcus faecalis (treatment No. 9) was the best treatment to decrease Salmonella in chickens and followed by Bacillus subtilis
treatment.
20-In general, from crossing results it is recommended that IN strain could be used as a sire and MA strain as a dam to improve growth, feeding, and microbiological, immunological traits. Moreover, crossing between MA and IN breeds decreased Salmonella colonization in broilers and improved the birds’ immunity against Salmonella.