Daidzein enhances immune function in late lactation cows under heat stress.

Heat stress decreases natural immunity making cows more vulnerable to diseases. A previous study reported that daidzein can enhance animal resistance to heat stress and regulate animal immunocompetence. However, it is unclear whether daidzein regulates the immune performance of late lactation cows under heat stress. In this study, late lactation cows in four groups were raised in hot weather and fed with basic diet, basic diet plus 200, 300, 400 mg/day daidzein, respectively, and the experimental period was 60 days. Blood was collected to examine the changes of serum total protein (TP), albumin (ALB), immunoglobulin G (IgG), interferon alpha (IFN-α), and interleukin-2 (IL-2). We found the levels of serum IgG and INF-α were significantly higher in late lactation cows after 300 and 400 mg/day daidzein treatment compared to those in the control group and 200 mg/day daidzein treatment (P < 0.05 or P < 0.01). Moreover, 300 and 400 mg/day daidzein treatment markedly increased serum IL-2 (P < 0.01), while the levels of serum TP and ALB were not changed by any concentration of daidzein treatment (P > 0.05). Daidzein can enhance the immunocompetence of late lactation cows and strengthen cow resistance to heat stress.

[Effect of bee pollen on development of immune organ of animal].

OBJECTIVE: To study on the effect of been pollen on development of immune organ of animal. METHOD: A total of 144 one day-old broilers were randomly divided into 2 groups, in which each group included 72 chickens. The control group was fed on the basal diet for 42 days, and that of experiment group supplemented 1.5% bee pollen. Six chickens in each group were selected and slaughtered at 7, 14, 21, 28, 35, 42 days respectively, and the thymuses, cloacal bursa and spleens were obtained, weighted, fixed in Bouin liquid and made into paraffin section. RESULT: Compared with control group, the weight and the relative weight of thymuses, cloacal bursa and spleens of experiment group increased significantly (P < 0.05) or extremely significantly (P < 0.01). In experiment group, the cortex of thymic lobule, bursa nodule and Periarterial Lymphatic Sheaths thicken obviously; the volume of bursa nodule, splenic nodule and ellipsoid augmented, and the germinal center of splenic nodule were obvious; the thymic corpuscle increased; the plica of cloacal bursa developed well and the degenerating of it retarded. CONCLUSION: The diet supplemented bee pollen could boost the early development of thymus and cloacal bursa, retard the degenerating of cloacal bursa and promote the immune response of spleen.