Abstract:

【Objective】 To evaluate the effects of duck hepatitis virus-Ⅰ(DHV-Ⅰ) on the body weight gain and the body length gain in duck and the effects of Silymarin on them in vivo. 【Method】 One hundred 11days old ducks, both male and female, were collected to be subjected to the test. The experiments were conducted in 5 groups: In geoup 1-3, the animals were inoculated with 1:5×104 diluted duck hepatitis virus infected allantoic fluids and given 0, 30 and 10 mg?kg-1bw?d-1 Silymarin orally respectively. In group 4, the animals were only given 10 mg?kg-1bw?d-1 Silymarin. The group 5 was the control one. During the treatment period, the food and water were given ad libitum except that the food was deprived for about 36 h once every four days in order to body-weighting. At the middle (15 d) and end of the treatment period (30 d), their body-length were measured. At the end of treatment, all the birds were slaughtered and the main visceral organs, pectoral muscles, thymus, lateral head of gastrocnemius were weighted for gaining the organ indexes (organ weight/corpse weight). 【Result】 In group 1, most (75%) birds died in 96h after inoculation of the virus and in group 2 some birds (20%) died in 120 h. All of other three groups survived during the treatment period (30 days). The survivals of group1 and 2 showed significant highly body weight gain and body length gain than that of other three groups. The eventual body weights were higher about 19.11% and 20.38% than that of group 5 respectively (P＜0.01) and the body lengths were also higher than that of group 5 (P＜0.05). The gastric indexes, intestinal indexes and pancreas indexes of the group 1 and 2 were significantly lower than that of group 5, but the pectoral muscle index was significantly higher than that of group 5. 【Conclution】 The silymarin had significantly protective effects for younger ducks from duck virus (DHV-Ⅰ) hepatitis.Inoculation of the virus could stimulated the body weight gain and body development in duckling. Silymarin had dual efficacy on the effects of the virus to stimulate the body weight gains. In lower dose, it can inhibit the virus’ effect, but in higher dose, it can’t.

Key words: duck hepatitis virus-Ⅰ(DHV), body weight gain, dual efficacy, silymarin