| Sorghum is a non-conventional energy feed with similar nutritional value to maize,but its antinutritional factor-tannin-limits its widespread use in feeds,while low tannin content sorghum varieties overcome this drawback and have great potential to replace maize.This experiment was conducted to investigate the effects of different sorghum levels in the diet on growth performance,blood index,tibia development,and intestinal health of Sichuan white geese from 1 to 21 and 21 to 70 days of age,respectively,and then to investigate the mechanism of sorghum’s effect on liver metabolism using metabolomics techniques to provide a scientific basis for the development and utilization of low-tannin sorghum as geese feed.The overall study consisted of three parts as follows.Experiment 1: Effect of low tannin sorghum in the diet on growth and development,blood index and intestinal health of Sichuan white geese from 1 to 21 days of age.A total of 240 1-day-old Sichuan white geese with an average weight of 80±5g and good health were randomly divided into 5 groups of 8 replicates each,with 6 geese in each replicate,and fed 0%,15%,30%,45%,and 60% sorghum proportion of the ration.The results showed that: 1)the mean daily weight gain of geese in the 60% group was significantly lower than that of the 0%,15%,30% and 45% groups(P<0.05),and there was no significant difference in mean daily feed intake and feed-to-weight ratio between the groups(P>0.05);the different levels of sorghum in the diets did not have a significant effect on geese organ index and tibia development(P>0.05).2)The plasma HDL content of geese in the 60% group was significantly higher than 0%,15%,30% groups(P<0.05);60% group of geese had significantly higher plasma total cholesterol than 0%,15%,30%and 45% groups(P<0.05);30% group of geese had significantly higher plasma glutathione peroxidase,superoxide dismutase activity than 0%,15%,45% and 60%groups(P<0.05).Plasma malondialdehyde content of geese in the 45% group was significantly higher than that in the 0% and 15% groups(P<0.05);3)Geese ileal villus height in the 30%,45% and 60% groups was significantly lower than that in the 0% and15% groups(P<0.05),and there was no significant effect of different sorghum levels in the diet on the activity of duodenal digestive enzymes activities in geese(P>0.05).So the level of low tannin content sorghum in the diet of Sichuan white geese from 1 to 21 days of age should not exceed 30%.Experiment 2: Effects of low tannin sorghum in the diet on growth performance,blood index,slaughter traits,meat quality and intestinal health of Sichuan white geese from 21 to 70 days of age.One hundred and eighty 21-day-old Sichuan white geese with an average body weight of 900±20g and good health were randomly divided into five groups of six replicates each,with six geese in each replicate,and fed diets with 0%,15%,30%,45%,and 60% sorghum ratios,respectively.The test period was 49 d.The results showed that1)the different sorghum levels in the diets had no significant effect on the mean daily feed intake,mean daily weight gain and feed-to-weight ratio of the geese(P>0.05);2)the plasma glucose content of the 45% group was significantly higher than that of the 15%and 30% groups(P<0.05),and the plasma HDL content of the 45% group was significantly higher than that of the 0%,15%,30% and 60% groups(P<0.05);3)The pectoral muscle rate was significantly lower in the 45% and 60% groups than in the 0%,15%,and 30% groups(P<0.05),and there were no significant differences in slaughter rate,semi-clean bore rate,full clean bore rate,leg muscle rate,abdominal fat rate,and skin fat rate between the groups(P>0.05);4)The pectoral muscle steaming loss rate was significantly lower in the 45% and 60% groups than in the 30% group(P<0.05),and the pectoral muscle meat color L* was significantly higher in the 45% and 60% groups than in the 0%,15%,30% group(P<0.05),60% group pectoral muscle crude fat content significantly higher than 0%,15%,30%,45%(P<0.05),45%,60% group geese pectoral muscle stearic acid,arachidic acid content significantly lower than 0%,15%,30% group(P<0.05),palmitoleic acid and oleic acid content of geese pectoral muscle in 45% and60% groups were significantly higher than those in 0%,15% and 30% groups(P<0.05),linoleic acid content of geese pectoral muscle in 0% group was significantly higher than those in 15%,30%,45% and 60% groups(P<0.05),linolenic acid content of geese pectoral muscle in 60% group was significantly higher than those in 0%,15%,30% and45% groups(P<0.05),the content of arachidonic acid and methyl eicosatrienoate in the pectoral muscle of geese in the 60% group was significantly lower than that in the 0%,15% and 30% groups(P<0.05);5)duodenal and jejunal p H in the 45% group was significantly lower than that in the 0% and 60% groups(P<0.05),and ileal p H in the 15%and 45% groups was significantly lower than that in the 0% and 60% groups(P<0.05).Different sorghum levels in the diet had no significant effect(P>0.05)on cecum p H and the number of viable bacteria of five species(total bacteria,Escherichia coli,Staphylococcus,Lactobacillus and yeast)in geese.So the level of low tannin content sorghum in the diet of Sichuan white geese from 21 to 70 days of age should not exceed45%.Experiment 3: Metabolomics-based study of the effect of sorghum in the diet on liver metabolism in geese from 21 to 70 days of age.The experimental design was the same as experiment two.The livers of Sichuan white geese in groups A(0%)and B(60%)were collected in 2 ml centrifuge tubes and stored in liquid nitrogen tanks at-80°C for measurement.The results showed that the differential metabolites(DEMs)were screened with VIP=1,difference multiplier FC=1and P value=0.05.A total of 191 DEMs were screened,and there were 79 up-regulated DEMs and 112 down-regulated DEMs in the 60% group compared with the 0% group.The KEGG differential metabolites were mainly amino acids,other secondary metabolites,carbohydrates,lipid metabolism,membrane transport,cofactors and vitamins,terpenoids and polyketides,and nucleotides.The DEMs were mainly enriched in protein digestion and absorption,D-amino acid metabolism,aminoacyl-t RNA biosynthesis,cancer center carbon metabolism,mineral uptake,valine,leucine and isoleucine biosynthesis,tryptophan metabolism,ABC transport proteins,phenylalanine metabolism,cytochrome P450,arginine and proline metabolism,and thiamine metabolic pathways.In summary,Sorghum feeding changed the metabolism in the liver of Sichuan white geese,mainly through protein digestion and absorption,D-amino acid metabolism,aminoacyl-t RNA biosynthesis pathway to inhibit amino acid metabolism and enhance the metabolism of fat and secondary substances. |
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