The effects of hydrolyzed yeast supplementation on growth performance, health and immune-physiological parameters in neonatal calves challenged with vaccine were investigated. Twelve Holstein calves were started in the experiment at 2 6 1 days of age and were studied for 35 days. Calves were randomly assigned to each of two dietary treatments, a control (CON) and hydrolyzed yeast (HY) group. The calves in the HY group received control calf starter supplemented with 0.2% HY. All calves were given calf starter ad libitum for 5 weeks starting in week 1. Calves were also given whole milk according to a step-down milking protocol. In order to induce immune responses, all calves were challenged with Hog cholera and Erysipelothrix insidiossa live vaccines by intramuscular injection at 3 weeks of age. Growth performance and feed intake were not affected by dietary treatment throughout the experimental period, except that the HY group had significantly higher ( P , 0.05) milk intake than did the CON group at 3 weeks of age. Calves in the HY group showed significantly better ( P , 0.05) fecal and health scores at 3 weeks compared to those in the control group. After vaccine challenge, neutropenia, lymphophilia and thrombocytopenia were observed in the CON group, but calves in the HY group did not show significant changes of leukocytes. The average concentration of serum haptoglobin in the HY group was significantly higher ( P , 0.05) at 1 and 3 days post-vaccine challenge (DPVC) than that of CON group. Feeding HY supplemented calf starter resulted in a higher ( P , 0.05) relative amount of bacterial and viral -specific IgA than in the CON group at 5 DPVC. Although the percentage of CD4 1 T cells was significantly ( P , 0.05) higher in the HY group than in the CON group at 22 DPVC, significant differences between groups after vaccine challenge was not observed during the experimental period. These results suggest that 0.2% HY supplementation in calf starter can improve the health status and immune-related serum protein production and affect blood cell composition in neonatal calves after vaccine challenge.

Bombyx mori nucleopolyhedroviruses (BmNPVs), isolated from a sericultural Korean farm, were purified and characterized by their DNA restriction pattern, virus replication, polyhedra production and gene structures. The EcoR I and Sal I fragments showed similar overall patterns with minor difference but distinguishable patterns in each isolate. There was no significant difference in the virus replication pattern, yield of total polyhedra production and polyhedra morphology, but the yield of released polyhedra by BmNPV-K1 in Bm5 cells was 2 to 5 times higher than that of other isolates. In comparative studies of p10 gene, BmNPV-K1 and K3 had same structure and they encoded a protein consisting of 94 amino acids. Although BmNPV-K2 encoded the same length of amino acids with BmNPV-K1 and K3, it had different structure, and BmNPV-K4 had the p10 gene encoding 70 amino acids.

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