| Due to the degradation of natural grasslands,house feeding and fattening have become the main breeding method for cashmere goats,but this can lead to excessive fat deposition and a decrease in meat quality.The research team found in the early stage that adding artemisia ordosica to the diet of cashmere goats reduced their growth performance,but it also reduced the body’s fat and cholesterol content,thereby improving the quality of lamb.On the basis of previous research,this thesis studied the effects of adding artemisia ordosica to the diet on muscle protein and amino acid composition,as well as plasma amino acid composition of cashmere goats.By analyzing the diversity of rumen and ileum microbiota and their correlation with muscle and plasma amino acids,growth and fattening performance,nutrient digestibility,and rumen fermentation parameters,the mechanism of the influence of artemisia ordosica on the growth and fattening performance and muscle nutritional quality of cashmere goats was explored,Provide theoretical basis for the production and application of artemisia ordosica in cashmere goats.The experiment selected 40 capricorn sheep of similar age(4 months old),similar weight,and healthy body condition from the Albas White Cashmere Goat Farm in Inner Mongolia.A single factor randomized trial design was used,and they were randomly divided into 2 treatment groups,with 20 sheep in each treatment group.One group is the control group(CON),fed with a basal diet with a concentrate to coarse ratio of 49:51;The other group is the experimental group(AOM),fed with a basic diet of 3% artemisia ordosica instead of an equal proportion of coarse feed.The pre feeding period is 14 days,and the formal period is 90 days.It is divided into the early stage of fattening(1-30 days),the middle stage of fattening(31-60 days),and the late stage of fattening(61-90 days).After the completion of fattening,8 goats of similar average weight were selected for each group,and they were fasted for 12 and 2 hours before slaughter.After slaughter,meat samples and rumen and ileal contents of four types of muscles were collected for subsequent measurement.The experiment in this thesis is mainly divided into three parts:Experiment 1 mainly studied the effect of adding artemisia ordosica to the diet on the composition of amino acids in the muscle and plasma of cashmere goats.The results showed that,compared with the control group,the diet supplemented with artemisia ordosica had a certain impact on the muscle nutritional quality of cashmere goats,and increased the content of crude protein,Cys and Phe in the longissimus dorsi muscle,Tyr in biceps femoris muscle,Phe in triceps brachii,Cys and Met in gluteus;Reduced Glu and Ala contents in gluteal muscles;The contents of Cys in biceps femoris muscle,Met and BCAA in triceps brachii,and Ser in gluteus also tended to decrease,while the contents of Phe and Arg in biceps femoris muscle tended to increase.Adding artemisia ordosica to the diet increased the levels of Asp,Thr,Ser,Gly,Met,Ile,Tyr,Phe,Lys,Arg,and Pro in the plasma of cashmere goats,as well as the levels of TAA,EAA,LAA,and EAA/TAA ratio in the plasma.The proportion of EAA/NEAA also showed an increasing trend;Reduced the levels of Glu,Ala,and Val in plasma.The proportions of amino acids EAA/TAA and EAA/NEAA in the muscle of cashmere goats are above 50% and 100%,respectively,indicating a high amino acid balance and high protein nutritional value.Experiment 2 mainly studied the effect of adding artemisia ordosica to the diet on the diversity of rumen microbiota in cashmere goats and its correlation with growth and fattening performance and muscle nutritional quality.The results showed that the differential genera of rumen bacteria in the CON and AOM groups of cashmere goats were Succinimonas,Candidatus＿Soleaferrea,Prevotella＿9,Ruminococcaceae＿UCG-009,Filimonas.There was no significant change in the diversity and richness of rumen microbiota in cashmere goats after adding artemisia ordosica to the diet.The dominant phyla was Bacteroidetes and Firmicutes,while the dominant family was Veillonellaceae and Prevotella.The dominant genus was Prevotella＿1,Rikenellaceae＿RC9＿gut＿group.In the rumen fluid of cashmere goats,the relative abundance of Succinimonas,Candidatus＿Soleaferrea,Prevotella＿9,Ruminococcaceae＿UCG-009 is significantly positively correlated with weight gain,fat and cholesterol deposition,nutrient digestion,and rumen isovaleric acid indicators related to the growth and fattening performance of cashmere goats,while negatively correlated with the content of some amino acids in muscle and plasma.The abundance of these bacterial genera is significantly reduced in the artemisia ordosica group;The relative abundance of Filimonas is negatively correlated with weight gain,fat and cholesterol deposition,nutrient digestion,and rumen fermentation indicators related to growth and fattening performance.However,the relative abundance of Filimonas is opposite to the correlation between Phe in the triceps brachii muscle and plasma Asp and Thr.The abundance of this genus of bacteria is significantly increased in the artemisia group.These bacterial genera are potential differential bacterial genera that cause decreased growth performance,improved muscle nutritional quality,and decreased fat deposition in cashmere goats.Experiment 3 mainly studied the effect of adding artemisia ordosica to the diet on the diversity of ileal microbiota in cashmere goats and its correlation with growth and fattening performance and muscle nutritional quality.The results showed that the differential genus of bacteria in the ileum of cashmere goats in the CON and AOM groups was [Eubacterium]＿coprostanoligenes＿group,Mycoplasma,unclassified＿f＿＿Lachnospiraceae,Marvinbryantia,Saccharofermentans,Candidatus＿Saccharimonas,Candidatus＿Arthromitus,Family＿XIII＿UCG-001,Lysinibacillus,horsej-a03,Anaerofustis,norank＿f＿Peptococcaceae,Denitrobacterium,norank＿f＿Christensenellaceae,Family＿XIII＿UCG-002,Anaerotruncus,Romboutsia,Prevotella＿9.Adding artemisia ordosica to the diet can reduce the diversity and richness of the ileal microbiota in cashmere goats.The dominant phyla in the ileum of cashmere goats are Firmicutes and Actinobacteria,the dominant family is Peptostreptococcaceae,Ruminococcaceae,and the dominant genus is unclassified＿f＿＿Peptostreptococcaceae,Intestinibacter.In the ileal contents of cashmere goats,[Eubacterium]＿coprostanoligenes＿Group,Denitrobacterium,horsej-a03,and Family＿XIII＿UCG-001.The abundance of bacterial genera in was significantly reduced in the artemisia ordosica group,and was significantly positively correlated with most parameters related to growth and fattening of cashmere goats,such as weight gain,fat and cholesterol deposition,nutrient digestion,and rumen fermentation.It was negatively correlated with protein,amino acids,and plasma amino acid content in some muscles;Prevotella＿9 is exactly the opposite.The abundance changes of these five bacterial genera are the key bacterial genera that cause decreased growth performance,improved muscle nutritional quality,and decreased fat deposition in cashmere goats.In summary,adding 3% artemisia ordosica to the diet had a significant impact on the abundance of related microbial communities in the rumen and ileum,reducing the content of fat and cholesterol in the body tissue,increasing the content of muscle protein,and thereby improving the nutritional quality of lamb.The potential key bacteria involved in the rumen were Succinimonas and Candidatus＿Soleaferrea,Prevotella＿9.Ruminococcaceae＿UCG-009,Filimonas.In the ileum were[Eubacterium]＿coprostanoligenes＿group,Denitrobacterium,horsej-a03,Family＿XIII＿UCG-001,Prevotella＿9. |
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