| In this experiment,through the studies on the effects of dietary sulphur amino acids levels on the growth performance,nitrogen digestibility,immune organ index,serum biochemical parameters and free amino acids in serum of taihang chickens during the brooding and growth period to determine the taihang chickens brooding and growth period of sulphur amino acids levels,and to provide the basis for establishing the standard of taihang chickens nutrition requirement and formulating the reasonable diet.Experiment 1: A total 600 taihang chickens with the same genetic background,same batch and normal development at aged of 1 day were randomly divided into 5 treatments with 6 replicates per treatment and 20 chickens per replicate.Single factor test design was adopted,and the feeding trail lasted 6 wk.Dietary sulphur amino acids levels were 0.54%,0.60%,0.66%,0.72% and 0.78%.The results showed as follow,1)Growth performance: when there was no significant effect in initial weight(P > 0.05),the dietary sulphur amino acids levels had significant effect on the weight of taihang chickens(P < 0.05),and the weight of 0.72% group was significant higher than 0.54% group(P<0.05);there were no significant differences between 0.54% and 0.60% groups(P > 0.05),and there were no significant differences between 0.66% with 0.72% groups(P > 0.05);the final weight,average daily gain and average daily feed intake of 0.72% group were significantly higher than 0.54% group(P< 0.05),and there were no significant differences between 0.66% and 0.72% with 0.78% groups(P > 0.05),and there were no significant differences between 0.54% and 0.60% groups(P > 0.05);there was no significant difference on the feed/gain(P > 0.05).2)Nitrogen digestibility: 0.72% was 3.35% higher than 0.54% group(P<0.05),and 0.72% groups was the highest,and there were no significant differences between 0.66% and 0.72% groups(P > 0.05).3)Immune organ index: the bursal index of 0.72% group was significantly higher than other groups(P < 0.05),and there were no significant differences between other groups(P > 0.05);thymus index of 0.72% groups was significantly higher than 0.54%,0.66% and 0.78% groups(P < 0.05),and there were no significant differences between 0.60% and 0.72% groups(P > 0.05);the spleen index of 0.72% was significantly higher than 0.54% and 0.60% groups(P < 0.05).4)Serum biochemical parameters: the uric acid of 0.72% group was significantly lower than other four groups(P < 0.05),and there were no significant differences between other four groups(P > 0.05);the albumin of 0.66%,0.72% and 0.78% groups were significantly higher than 0.54% group(P < 0.05),and there was no significant difference between 0.54% and 0.60% groups(P > 0.05);the total protein of 0.72% group was the highest,and significantly higher than 0.54% group(P < 0.05),and there were no significant differences between other three groups(P > 0.05);the alkaline phosphatase of 0.72% and 0.78% groups were significantly higher than 0.60% and 0.66% groups(P < 0.05).5)Free amino acids of serum: the level of aspartic acid and glycine of 0.54%?0.60% and 0.66% groups were significantly higher than that of other groups(P < 0.05),and there were no significant difference between the there groups(P > 0.05),there were no significant differences between 0.72% and 0.78% groups(P > 0.05);with the level of dietary sulphur amino acid increasing,serum free cysteine and methionine levels increased significantly in a linear manner(P < 0.05),and the 0.78% groups was highest.In addition,the level of sulphur amino acids had no significant effect on other free amino acids(P > 0.05),and the total amount of free amino acids was not affected by the level of sulphur amino acids(P > 0.05).Experiment 2: A total 450 taihang chickens aged of 7 weeks were randomly divided into 5 treatments with 6 replicates per treatment and 15 chickens per replicate.Single factor test design was adopted,and the feeding trail lasted 6 wk.Dietary sulphur amino acids levels were 0.50%,0.58%,0.66%,0.74% and 0.82%.The results showed as follow,1)Growth performance: when there was no significant effect in initial weight(P> 0.05),the dietary sulphur amino acids levels had significant effect on the weight of taihang chickens(P < 0.05),and the weight of 0.66% group was significant higher than 0.50% group(P < 0.05);there were no significant differences between 0.66% and 0.74% groups(P > 0.05);the final weight,average daily gain and average daily feed intake of 0.66% group was significantly higher than 0.50% group(P < 0.05),and there were no significant differences between 0.58%,0.74% and 0.82% groups(P > 0.05);the feed/gain of 0.50% and 0.58% groups were significant higher than 0.82% groups(P > 0.05),there was no significant difference on the other groups(P > 0.05).2)Nitrogen digestibility: 0.66% was 2.16% higher than 0.50% group(P < 0.05),and 0.66% was the highest,there were no significant differences between 0.58%,0.66% and 0.74% groups(P > 0.05).3)Immune organ index: there were significant effects on the bursal index and spleen index(P < 0.05),and the bursal index of 0.74% group was significantly higher than other four groups(P < 0.05),and there were no significant differences between other four groups(P > 0.05).4)Serum biochemical parameters: the albumin of 0.66% group was significantly higher than 0.50% and 0.58% groups(P < 0.05),but there were no significant differences on the uric acid,albumin and alkaline phosphatase(P>0.05).5)Free amino acids of serum: the level of valine and lysine of 0.54% and 0.60% groups were significantly higher than those of other groups(P < 0.05),and there were no significant difference between other four groups(P > 0.05),the level of isoleucine of 0.66% and 0.82% groups were significantly higher than of 0.50% groups(P<0.05);with the level of dietary sulphur amino acid increasing,serum free cysteine and methionine levels increased significantly in a linear manner(P< 0.05),and the 0.82% groups was the highest.In addition,the level of sulphur amino acids had no significant effect on other free amino acids(P > 0.05),and the total amount of free amino acids was not affected by the level of sulphur amino acids(P > 0.05).To sum up,under the conditions of this experiment,the appropriate level of sulphur amino acids in the diet of taihang chickens at the brooding period was 0.72%,the appropriate level of sulphur amino acids in the diet of taihang chickens at the growth period was 0.66%. |
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