Effects Of Dietary NDF/NFC On Lactation Performance,Blood Biochemical Indices And Milk Amino Acid And Fatty Acid Profile Of Lactating Donkeys

The structure and proportion of dietary carbohydrates are important factors affecting milk yield and milk quality of dairy animals.This paper studied the diet Neutral Detergent Fiber（NDF）/Non Fiber Carbohydrates（NFC）affect the performance of lactation donkey milk,and milk composition,nutrition digestion and metabolism,blood biochemical indexes,blood and milk in amino acid（AA）,fatty acid（FA）and mineral elements content of Angle probes into the influence mechanism of may,The results provided a theoretical basis for rational collocation of concentrate and roughage in the diet of lactation donkey and optimization of the composition of donkey milk.Sixteen Dezhou donkeys with foals with similar age（6.73±1.16 years）,body weight（250.84±27.21 kg）,parities（3.25±1.12 parities）and lactation days（40±4 days）were divided into control group（CON）and experimental group（TRM）with 8 donkeys in each group by single factor completely randomized design.Piglets in the CON group were fed the diet with a concentrate to forage ratio of 30:70（NDF/NFC was 1.65）,and those in the TRM group were fed the diet with a concentrate to forage ratio of 40:60（NDF/NFC was 1.48）.The energy and protein levels of the two groups were the same.The experiment lasted for 8 weeks.During the test period,the female donkey was separated from the foal twice a day for 3h each time and for 6h all day.Record milking volume head by head every day;Weekly determination of milk composition;Every two weeks,the female donkeys were weighed on an empty stomach before morning feeding,and on the last day of the experiment,the female donkeys were collected on an empty stomach.This thesis includes three experiments.Experiment 1 studied the effects of dietary NDF/NFC on lactating performance and nutrient digestion of lactating donkeys.The results showed that compared with the high concentrate diet（NDF/NFC=1.48）,the low concentrate diet（NDF/NFC=1.65）could significantly increase the milking yield,estimated milk yield,milk production efficiency and milk protein synthesis efficiency of female donkeys（P<0.05）;In addition,the DM,CP,ADF,NDF and Ca digestibility ratio,energy utilization ratio and the nitrogen metabolism rate were increased,but the content of milk components was not significantly affected.In experiment 2,the effects of dietary NDF/NFC on serum biochemical indices,related hormone concentrations and mineral elements contents in serum and milk of lactating donkeys were studied.The results showed that the concentrations of TP,ALB,PRL and HYD in serum of lactating donkeys were significantly increased with the diet of NDF/NFC=1.65 compared with the diet of NDF/NFC=1.48 under the conditions of iso-energy and iso-nitrogen,and the concentration of EGF tended to increase.The concentrations of CHO,CG and FSH in serum were significantly decreased,while the concentrations of UREA and D₃HB showed a decreasing trend.The contents of Ca in serum and milk were significantly increased,while the contents of Fe in blood and Cu in milk tended to increase（P=0.08 and P=0.06）.In experiment 3,the effects of dietary NDF/NFC on the contents of amino acids and fatty acids in milk and plasma of lactating donkeys were studied.The results showed that when dietary NDF/NFC increased from 1.48 to 1.65,the contents of Thr,Met,His,Lys,Pro,BCAA and LAA in plasma and the ratios of Thr,Phe,His,Lys,Pro and LAA in milk were increased.The balance of AA in donkey’s milk was improved by increasing the yield of most single AA（except Ser and Val）and TAA,EAA,NEAA,LAA and BCAA.Increasing the NDF/NFC ratio could increase the plasma MCFA,LCFA,n-3 PUFA,n-3 LCPUFA and n-6 LCPUFA contents and feed amount,and increase the ratios of C18:3n3,PUFA and n-3 PUFA in milk of lactating donkeys.To improve the yield of most single FA and MCFA,LCFA,PUFA,n-3 PUFA,n-6 PUFA,n-3 LCPUFA and n-6 LCPUFA in donkey milk,to increase the yield of EPA and DHA,and to improve the FA quality of donkey milk.In conclusion,under the condition of iso-energy and iso-nitrogen,appropriately increasing the proportion of high-quality roughage and increasing the NDF/NFC from1.48 to 1.65 can promote energy digestion and protein metabolism,milk production efficiency,milk protein synthesis efficiency,milk AA and FA production,and milk production performance of lactating donkeys.In addition,the composition of AA and FA in donkey milk was optimized,the ratio of LAA in donkey milk and the ratio of C18:3n3,PUFA and n-3 PUFA in milk FA were increased,and the milk quality was improved.