5-SUMMARY
The present study was carried out to investigate the effect of different nitrate levels in drinking water and the effect supplementation of Vit C or Vit E with Se or probiotic on recovery of productive, physiological, reproductive and nutritional traits of NZW bucks.
Forty two NZW male rabbits aged about 16 weeks and weighing on average (2179.76 ± 50.8g) were divided randomly according to their live body weight into six similar groups of 7 rabbits each. Rabbits in the first treatment drank tap water (control), treatments (2 and 3) drank tap water supplemented with 350 or 700 ppm of nitrate respectively, while treatments (4, 5 and 6) supplemented with 700 ppm plus Vit C (200 mg / liter) orVit E with Se (1 ml / liter) (200 mg Vit E plus 0.2 mg sodium selenite) or probiotic (1 g/Liter) respectively. The duration of the feeding experiment was (12 month). At 32 weeks of age of rabbits three animals from each treatment were used to determine the digetibilities and nutritive values of the experimental rations. Semen collection was carried out weekly from all bucks at the 28 weeks of age and continued for 16 weeks. At 32 weeks of age of rabbits four bucks per treatment were used in matting NZW female to evaluate fertility.
Results of this study can be summarized as follow:
1- Addition of 700 ppm nitrate significantly (p<0.05) decreased DM intake, digestibility coefficients of DM , OM, CP, CF, NFE, NDF, ADF and nutritive values expressed as DCP or TDN.
2- Dry matter intake, digestibility coefficients expect EE and nutritive values were significantly (p<0.05) higher in rabbits drinking water supplemented than those drinking water without any supplementation.
3- Addition of 700 ppm of nitrate in drinking water significantly (p<0.05) increased water and nitrate intake.
4- Addition of 350 or 700 ppm nitrate had a non significant effect (p<0.05%) on feed intake.
5- The interaction between nitrate level and the supplementation of Vit C or Vit E with Se or probiotic significantly (p < 0.05) decreased water and nitrate intake and significantly increased feed intake.
6- Body weight at 28, 32 and 36 week was significantly (p< 0.05) increased of rabbits supplemented with 350 and 700 ppm nitrate compared to the control.
7- The interaction between nitrate level (700 ppm) and the supplementation of Vit C or Vit E with Se and probiotic had a non significant effect (p < 0.05) on body weight at all tested ages.
8- The water intake at 24,28, 32, 36, 40, 44 and 48 weeks significantly (p < 0.05) increased at 700 ppm nitrate compared to control or 350 ppm nitrate groups.
9- There was a significant interaction between nitrate level (700 mg) and the supplementation of Vit C or Vit E with Se and probiotic on water intake at 20, 24,28,32,36 and 40 and 48 weeks of age.
10- There were no significant differences in the total WBC᾽s count, PA, and PI among the experimental groups
11- Nitrate supplementation at 700 ppm/Liter drinking water significantly decreased globulin and Hgb concentrations, RBC᾽s count and PCV %.
12- The Interaction between nitrate level (700 mg) and the supplementation of Vit C or Vit E with Se and probiotic resulted in significantly (p< 0.05) increased in Hgb concentration, RBC᾽s count and PCV %.
13- Addition of nitrate at 350 or 700 ppm/Liter drinking water had a non significant effect (p< 0.05) on blood plasma total protein, albumin and cholesterol concentrations.
14- There was non significant interaction between the nitrate level (700 ppm) and the supplementation of Vit C or Vit E with Se and probiotic on blood plasma total protein, albumin and cholesterol concentrations.
15- Supplemented rabbits with Vit C or Vit E with Se and probiotic significantly (p<0.05)decreased urea, creatinine, AST , ALT concentrations in blood and seminal plasma compared with the rabbits drank water supplemented with 700 ppm nitrate.
16- The total antioxidant capacity of blood plasma and testosterone concentration in blood plasma and seminal plasma were significantly (p< 0.05) decreased of rabbits drank water supplemented with 700 ppm nitrate than those drank water supplemented with 350 ppm nitrate or control group.
17- Nitrate level at 700 ppm in drinking water significantly decreased total protein, albumin concentrations in seminal plasma compared to the group with 350 ppm nitrate .
18- A level of 700 ppm nitrate on drinking water significantly increased urea, creatinine, AST and ALT concentrations in blood and seminal plasma.
19- The nitrate supplementation and The interaction between 700 ppm nitrate and the supplementation of Vit C or Vit E with Se and probiotic had insignificant effect on carcass characteristics except heart weight%, liver weight %, kidney weight% and liver weight (gm)
20- Supplementation of 700 ppm nitrate significantly decreased semen colour, semen viscosity, live sperm %, advanced motility % , sperm concentration and total sperm output compared to the groups supplemented or not with 350 ppm nitrate.
21- Addition of nitrate at 700 ppm in drinking water significantly increased age at first ejaculation, dead sperm %, abnormal sperm %, total dead sperm count and total abnormal sperm count, compared to those supplemented or not with 350 ppm of nitrate.
22- Addition of the nitrate at (350 or 700 ppm) and the interaction between nitrate levels and different agents had a non significant effect (p<0.05) on number of weaned offspring, total weight of weaned offspring, kid weight and livability.
23- Supplementing rabbits with 700 ppm nitrate significantly (p<0.05) decreased fertility, number of offspring, total offspring weight and penny weight as compared with the siredly in the control bucks.
24- The supplementation of Vit C, Vit E with Se and probiotic significantly increased fertility, number of offspring, total offspring weight and penny weight of rabbit siredly bucks supplemented with 700 ppm of nitrate.
IN CONCULSION
The results indicated that up to 350 ppm of nitrate had no harmful effect on nutritional, productive, reproductive, physiological traits and histpathologycal changes of liver, kidney and testes. On the other hand, increasing nitrate level to 700 ppm negatively affects the aforementioned criteria. Furthermore, supplementation of Vit C, Vit E with Se and probiotic was equally effective for relief the negative effects coincided with 700 ppm of nitrate offering protective agents for rabbits producers in area with high nitrate up to 700 ppm.