Digestible Lysine, Sulphur-Containing Amino Acids And Threonine Requirements Of Mahua Broiler Chicks In Guangxi Province

Three experiments were conducted to determine the available Lys requirement of Mahua broiler chicks during the period 1 to 21 days and 22 to 42days,and the requirements of available Sulphur-containing amino acids and Threonine in 1-21d of age. All experiments were in a single factorial arrangement.All diets kept iso-energetic(3.0Mcal/kg of ME),were composed of corn.soybean meal.fish meal.Experiment 1 was conducted with a total of 1200 one-day-old Mahua broilers birds from 1 to 21d and 22 to 42d of age , designed with five levels of available lys(%) :1.22,1.12,1.02,0.91and 0.81 during the period 1 to 21 days ; 1.13,1.02,0.92,0.82 and 0.71 during 22 to 42 days; The objectives of experiment 2 was to determine the available SAA and available Thr requirement during the period 1 to 21days,used a number of 1600 one-day-old Mahua broilers,both trials contained five levels of digestible amino acids, available SAA trial(%): 1.02,0.91,0.79,0.67 and 0.56, available Thr trial (%):0.88.0.78,0.69,0.59 and 0.49. The results showed that in a certain range of available lys, SAA and Thr, with the determined amino acid increasing,chicks gained higher average daily gain(ADG)(P<0.05) and feed conversion ratio(FCR) (P<0.05).In Experiment 1, from 1 to 21 days,ADG and FCR of chicks at 1.12% was much better than 0.91% and 0.81% level(P<0.01),but had no significant difference compared with 1.02% or 1.22% level (P>0.05),the feed;gain at 1.22% was lower than at 1.12%(P<0.05).during 22 to 42d of age,when available lys of diet was 1.02%,the ADG and FCR of chicks were significantly better than 0.82% (P<0.05) and 0.71% level(P<0.01),and no difference was showed between 1.02%, 1.13% and 0.92% level.In available SAA trial, broilers gained the highest ADG and the lowest F/G at 0.91% level.difference of ADG between 0.91% and 0.56% was significanf(P<0.05),and F/G of 0.91% level was much lower(P<0.01) than at 0.56%,but between 1.02%, 0.79% or 0.67% levels.there were no difference(P>0.05).In available Thr requirement study,at 0.78% level,both ADG and FCR were the best,the ADG higher than 0.46% level(P<0.01),F/G ower than 0.46% or 0.59% level(P<0.01).Judge by ADG and F/G,The optimum available lys.SAA and Thr requirement of Mahua broiler were 1.02%,0.67% and 0.59% respectively for ADG ,1.12%,0.67% and 0.69% respectively for F/G during the period 1 to 21 days;In the days of 22 to 42 period.the optimum requirement was 0.82% for ADG and F/G.