Effects of Dietary Antioxidants Supplementation on Cellular Immune Response and Evaluation of Their Antimicrobial Activity Against Some Enteric Pathogens in Goats

3 Abstract: The present study aimed to investigate the effects of the use of natural antioxidant such as Nigella sativa or black cumin seeds (BCS) and organic multi-nutrient antioxidants, as dietary supplements on cellular immune status and evaluate their antimicrobial effects on some enteric pathogens (E. coli and C. perfringens) in goats. We also aimed to detect certain virulence genes of these pathogens using Multiplex PCR. Fifteen, 4-6 months old Baladi goat kids were divided into three equal groups (n=5). Group A was kept as control and fed the basal diet, group B received basal diet supplemented with crushed BCS at ratio of 2% and group C received basal diet supplemented with the organic multi-nutrient antioxidants; zinc methionine (Zn-Met.) and vitamin E with selenium enriched yeast (Vit E\Se) at levels of 2g\kg of diet. All treatments extended for 120 days. Heparinized blood samples were aseptically collected from all goats at day 0 and once at the end of experimental period for immune cell function studies. The cellular immune responses of experimental animals were assessed by lymphocyte proliferation using XTT kit and phagocytic % & phagocytic index using candida albicans. Fecal samples were collected at day 0 and subsequently at 30 days intervals up to 120 days of experimental period for bacteriological examination and total bacterial counts. Multiplex PCR was carried out for detection of virulent genes F41 and K99 genes for E. coli and alpha, beta and epsilon toxin genes for C. perfringens. The obtained results revealed a significant elevation of lymphocyte and phagocytic activities in groups B and C received antioxidants compared with goats in group A fed the basal diet. Moreover, BCS showed antimicrobial effect against some enteric pathogens by inhibition of the intestinal bacterial counts of E. coli and C. perfringens. Detection of some certain virulent genes for the studied pathogens showed positive results to "K99" gene for E. coli and alpha & epsilon toxin genes for C. perfringens type D. In conclusion, dietary supplementation with either N. sativa or multi- nutrient antioxidants (Zn-Met. and Vit E\Se) can be used to provide potent immune cell function in goats. Moreover, N. sativa had proved to have antibacterial effect against some enteric pathogens.