Abstract:

 This experiment was conducted to study the effects of dietary vitamin B₁ level on growth performance, gastrointestinal digestive enzymes activity and TPK1 gene expression of Qingnonghui geese, to determine vitamin B₁ requirement in different weeks. Three hundred and sixty 1-day-old Qingnonghui geese were randomly selected and divided into 6 treatments with 6 replicates per treatment and 10 geese in each replicate. The level of vitamin B₁ in each group were 1.0, 2.8, 4.6, 6.4, 8.2, 10.0 mg·kg^-1 at weeks 0 to 4, and 0.8, 2.6, 4.4, 6.2, 8.0, 9.8 mg·kg^-1 at weeks 5 to 15. The experiment lasted for 15 weeks．The results showed as follows: 1) The relationship between daily weight gain and requirement presented quadratic model in two growth stages, the optimal dietary levels of vitamin B₁ are 5.60 mg·kg^-1 at weeks 0 to 4, and 4.98 mg·kg^-1 at weeks 5 to 15. The relationship between activity of pepsin in glandular stomach contents and requirement presented quadratic model in two growth stages, the optimal dietary levels of vitamin B₁ are 5.48 mg·kg^-1 at weeks 0 to 4, and 6.03 mg·kg^-1 at weeks 5 to 15. The relationship between activity of trypsin and requirement presented quadratic model at weeks 0 to 4, the optimal dietary levels of vitamin B₁ was 5.46 mg·kg^-1. The relationship between activity of trypsin in duodenum contents and requirement presented quadratic model at weeks 0 to 4 and 5 to 15, the optimal dietary levels of vitamin B₁ were 5.36 and 5.41 mg·kg^-1, respectively. 2) At 15 weeks of age, the growth rate of geese and activity of pepsin, trypsin and amylase in pancreas and trypsin and amylase in duodenum contents were positive correlation (P<0.01)，and activity of lipase in pancreas was positive correlation (P<0.05). 3) At 15 weeks of age, 6.2 mg·kg^-1 vitamin B₁ significantly increased the expression of TPK1 gene (P<0.05) and the expression of TPK1 gene and activity of pepsin, lipase in pancreas and amylase in duodenum contents were positive correlation (P<0.01). In conclusion, consideration from the growth performance, the requirement of vitamin B₁ appears to decline with the age. The requirement of vitamin B₁ are 5.60 mg·kg^-1 at weeks 0 to 4，and 4.98 mg·kg^-1 at weeks 5 to 15; Vitamin B₁ effects the expression of TPK1 gene in liver and TPK1 gene regulates the activity of pepsin, lipase in pancreas and amylase in duodenum contents, then regulating the growth performance.