Locoweeds cause significant livestock
poisoning and economic loss all over the world. The purpose of this study was to investigate the immune effects of locoweed toxin,
swainsonine (SW) and
human serum albumin (HSA) conjugate (SW-HSA), on goats. Twenty-four Sannon goats were randomly separated into immune control group (eight goats), immune
poisoning group I (six goats), immune
poisoning group II (six goats) and
poisoning control group (four goats). Immune control group, immune
poisoning groups I and II were first vaccinated with
SW-HSA conjugate. The
poisoning control group, immune
poisoning groups I and II were then fed with 10.0 g/kg BW/day dry
powder of Oxytropis kansuensis Bunge everyday morning. The immune control group was supplied with an alfalfa-based diet. Blood samples of these experimental animals were collected at different time interval. Immunoassay was performed using indirect ELISA and E-rosette technique. The results show that, after second booster immunization: (1) anti-SW antibody level in some goats increased to 2(8), which proves that
SW-HSA conjugate can induce experimental animals to produce high-level anti-SW antibody in their bodies; (2) the high-level antibody in their bodies could maintain 30 days, and decreased gradually after
poisoning experiment (in our experiment, there was a return of the antibody level on day 21 after
poisoning experiment); (3) the decreasing of the E-rosette rate of the immune
poisoning group was delayed 14 days, which suggests that SW-HSA could low down the loss of the immunity of the goats; (4)
swainsonine concentration in the blood was significantly lower (p<0.01) in the immune
poisoning groups than that in the
poisoning control group, and there was no significant difference (p>0.01) between the two immune
poisoning groups within the
poisoning experiment.