| Stachyose belongs to α-oligogalactose,is a four-carbon sugar,and is also a major functional component of oligosaccharides.The aim of this experiment was to study the effects of different levels of stachyose on performance,nutrient metabolism,nonspecific immune function,cecal skatole concentration,gene expression and enzyme activity of cytochrome P450(CYP450,CYP)in liver of broilers.In addition,this experiment also explored the effect,mechanism and suitable addition of stachyose on skatole in broilers.In this experiment,360 one-day-old Arbor Acres(AA+)broilers were selected by single-factor randomized experimental design,and randomly divided into 6 groups,each group had 6 replicates and 10 chickens in each replicate.In the positive control group,corn-soybean meal diet was fed.In the negative control group,corn-nonsoybean meal diet was fed.In the experimental groups,0.4%,0.5%,0.6% and 0.7% stachhyose were added to the negative control group respectively.In all the groups,the nutritional levels of the diets in each group were the same,and the conditions for feeding and management were also the same,all of which were free to eat and drink.The experimental period was 49 days,which was divided into two stages: 1-28 days old and 29-49 days old.At the end of the feeding experiment,the blood,cecal contents and liver tissue samples of the broiler chickens were collected in duplicate units,and various indexes were determined.The results showed that:(1)Production performance: during the whole feeding period,the average daily gain(ADG)and average daily feed intake(ADFI)of broilers in the positive control group were significantly higher than those in the other groups,and the feed-gain ratio(F/G)was significantly lower than those in the other groups(P<0.01).Compared with the negative control group,F/G(P<0.01)of broilers in stachyose groups of 0.5%,0.6% and 0.7% aged 1-28 days decreased significantly.From 29 to 49 days old,ADG(P<0.05)increased significantly in 0.5%,0.6% and 0.7% stachyose groups,while F/G(P<0.05)decreased significantly in 0.5% and 0.7% stachyose groups.At 1 to 49 days of age,F/G(P<0.01,P <0.05)was significantly reduced in the 0.5% and 0.7% stachyose groups.There was a significant linear relationship between the F/G and stachyose addition levels in broilers(P<0.05).Stachyose was suitable for 0.5% and 0.7%.(2)Nutrient metabolic rate: compared with the negative control group,broilers in the positive control group,the apparent metabolic rate of dry matter,crude protein,ether extract,phosphorus and energy were significantly higher than those in the other groups(P<0.01).In 0.5% and 0.7% stachyose groups,the protein metabolic rate(P<0.01)of broilers was significantly increased.In stachyose group,the apparent metabolic rates of dry matter,ether extract,calcium and energy were significantly increased.There was a significant linear and quadratic relationship between nutrient apparent metabolic rate and stachyose addition level(P<0.05).Stachyose is suitably added in an amount of 0.43% to 0.81%.(3)Cecal indole,skatole and organic acid concentrations: in 0.5% and 0.7% stachyose groups,the concentration of indole in ceca of broilers decreased significantly(P<0.05).In the negative control group,the skatole content in cecum of broilers was significantly higher than that of the other groups(P<0.01).There was a significant linear and quadratic relationship between skatole concentration and stachyose addition level in broiler chickens(P<0.05),and a significant linear relationship with sputum concentration(P<0.05).When the dosage of Stachyose was 1.0%,the skatole concentration in ceca was the lowest.Compared with negative control group,in 0.5% and 0.7% stachyose group,the p H value of cecum of broilers decreased significantly(P<0.05).In stachhyose groups,the content of acetic acid and propionic acid in cecum of broilers increased significantly(P<0.05).In the 0.4% and 0.7% stachyose groups,cecal lactate content(P<0.05)was significantly reduced.In the negative control group,the cecal butyric acid content was significantly lower than those in the other groups(P<0.05).Cecal p H,acetic acid,propionic acid and lactic acid were significantly correlated with stachyose levels(P<0.05).Acetic acid,propionic acid,butyric acid and lactic acid showed a significant quadratic relationship with stachyose level(P<0.05).When the amount of stachyose added was 0.58%,the cecal acetic acid concentration was the highest.When the amount of stachyose added was 0.38%,the concentration of cecal butyric acid was the highest.(4)Non-specific immune function: there was no significant difference in serum immunoglobulin(Ig A,Ig M,Ig G),complement protein 3 and lysozyme among the treatments(P>0.05).(5)Liver CYP450 m RNA expression and enzyme activity: in 0.5% and 0.7% stachyose group,the expression of CYP3A4 gene in broiler liver was significantly higher than that in the negative control group and 0.4% stachyose group(P<0.05).There was no significant difference in the expression of CYP1A2 and CYP2D6 genes in the liver of each group(P>0.05).There was no significant difference in the activity of the three genes(P>0.05).In conclusion,adding stachyose to corn-nonsoybean meal diet significantly improved production performance and nutrient metabolic rate of broilers,decreased the concentrations of indole and skatole in cecum,the fermentation mode of cecum was changed,and the p H value was decreased.It is suggested that the optimum addition level of stachyose was 0.5%-1.0%. |
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