Influence Of Differently Added Level Of Dietary Zinc On Growth And Development And Reproductive Performance Of ISA Cock (P.S)

75 YiSha parents breeding cocks were selected as trial animal, which were divided3groups, 0. 60. 180 (Zn mg/kg) was added to base ration respectively. At the age of 12~ 18 week-old, measured and observed body weight and indexes of body measurement and changes of secondary sex character. At the age of 12. 14. 16 and 18week-old, by slaughter trial , weight of heart, liver, spleen, glandular stomach, gizzdar, small gut, large gut, cecum and testis were measured, at the same time, digestive tract length was measured, observed histologic changes of testis at the age of 16and 18 week-old. Results indicated : During experiment, body weight gain and body size increase were not significantly different (p>0.05) . from 15to 17 week-old, blade length of 180mg Zn group was longer than one of 0 mg/kg Zn group (p < 0.05 )> 60 mg/kg Zn group > 0 mg/kg Zn group (p < 0.05 ). 180mg/kg Zn group and 60 mg/kg Zn group was not significantly different (p>0.05), while ,blade height among groups was not significantly different (p > 0.05 ); from 14 to 18 week-old , relative testis weight was 180mg /kg Zn group > 60 mg /kg Zn group>0 mg/kg Zn group (p<0.05) in turn, tissue and structure of testis has changed, with added zinc in ration increasing, diameter of convoluted seminiferous tubule also increased, at the age of 16, diameter of convoluted seminiferous tubule of 0 mg/kg Zn group, 60 mg/kg Zn group, 180mg/kg Zn group were 109.92um, 143.65um, 188.25um (p<0.05) respectively; at the age of 18, diameter of convoluted seminiferous tubule of 3 groups were 108.11um, 171.59um , 286.03um (p<0.05); respectively; development of 0 mg/kg Zn group convoluted seminiferous tubule was normal , development of 60 mg/kg Zn group convoluted seminiferous tubule was faster than one of 0 mg/kg Zn group, there were a few of sperms and degenerative cell in tubule, development of 180mg/kg Zn group convoluted seminiferous tubule was fastest , there were a plenty of sperms and a lot of degenerative spermatiferous cells .Added level of dietary zinc affected growth and development in cock, at the same time , influenced sex gland development significantly (p<0.05) .