الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Total of 39 adult New Zealand white (NZW) rabbit does as experimental animals as well as five fertile rabbit bucks for natural mating were used in this study. Rabbit does were equally divided into 3 groups G1: control.G2: was given daily oral dose of 5g/l of both (Ca + Mg).G3: was given drinking water mixed with 5g/l of both (Na + K) for 15 days pre-mating. Three days after mating, three does from each group were taken to slaughter and their embryos were individually collected and exposed for sex detection using PCR (primary sex detection). Does in each group (n=10) were kept till natural delivery for the 1st and 2nd parities without treatment.
LBW of does was not affected by mineral treatment at 0 time and 2 and 4 weeks post treatment. During the treatment period (0-2 wk) or (2 wk of treatment -2 wk post- treatment), average weight gain was lower (P<0.05) in G2 than in G3 and G1. Weight gain in all groups was higher at 2-4 wk post-treatment than that at 0-2 wk post-treatment due to incidence of pregnancy in all groups at 4 weeks post-treatment. The average daily feed intake was lower (P<0.05) in G2 than in G3 and G1. Mineral treatment in G2 and G3 resulted in increase (P<0.05) in number of corpora lutea, bleeding follicles and total embryos and decreased (P<0.05) number of large follicles as compared to those in G1. However, number of small follicles and total follicles was not affected significantly by mineral treatment. Ovulation rate increased (P<0.05) in G2 and G3 as compared to G1.However, recovery rate did not differ significantly among experimental groups. Conception rate (CR) was higher (P<0.05) in G2 (80%) than in G3 and G1 (60%). After the 1st parity, average of litter size (LS) was insignificantly lower in G2 than in G3 or G1. After the 2nd parity, LS was lower (P<0.05) in G3 than in G2 and G1. After the 1st parity, doe rabbits in G2 produced more female births (74.2%), and those in G3 yielded more males (66.5%) than that recorded in males (46.3%) and females (53.7%) of G1. No differences in sex ratio after the 2nd parity among all groups. Using PCR doe rabbits in G2 produced more female embryos in vitro 72.2% .G3 produced more males 69.7%. The sex ratio of in vitro detected embryos of the control rabbit does was 44.0: 56.0 male: female. The obtained results in this study indicated that preconception treatment of doe rabbits with relative excess of Ca + Mg or Na + K would favor the birth of desirable genders, without adverse effects on growth performance, reproductive performance or mineral concentration in blood.