Studies On A Technique For Production Of Fruit-Flavored Milk And Metabolic Changes Of The Fruit Flavor Compounds In The Lactating Cow

The metabolic changes of the mixed fruit flavor meal in the rumen, blood and mammary gland of the lactating cow by rumen cannulas, arterio-venous catheter, and mammary gland culture technique were studied in this paper. The results were as follows:Part1 The development of measuring method for the mixed fruit flavor meal The best extraction parameter of SPME (Solid Phase Microextraction), the different fiber, electrolyte, extraction temperature and time were screened out in this trial. The results showed:①The fiber, electrolyte, extraction temperature and time of the SPME was PDMS, NaCl (0.32g/mL), 50℃and 30min, respectively.②There were 70 compounds in the mixed fruit flavor meal, including ester, mellow, aldehyde, ketone and hydroxybenzene, and so on.Part2 Studies on the optimal supplemental dosage of the mixed fruit flavor meal and effects on the cow performance and milk flavor30 lactating cows with the same weight, lactation(71±5d) and milk yield were divided into five groups to investigate the effects of the mixed fruit flavor meal on the cow performance and milk flavor in peak milk, the trail was continuously taken out in lactation(152±4d). During the period, the cows were fed a basal diet adding different dosage mixed fruit flavor meal, i.e 0, 5000, 6500, 7500 and 9000g/t (based on DM of concentration), respectively. The results showed:①the mixed fruit flavor meal could improve the milk quality and flavor, and the optimal supplemental dosage of the mixed fruit flavor meal was 7500g/t.②the milk yield in peak milk was increased and the decline rate of milk yield in the mid and late lactation was decreased. The total economic benefits were significant.Part3 Studies on the metabolic changes of the mixed fruit flavor meal in the rumen, blood and mammary gland⑴The metabolic changes of the mixed fruit flavor meal in the rumenTwo cows with permantent ruminal cannulas were fed a basal diet in early lactation and used to investigate the effects of the mixed fruit flavor meal on the fermentation index and flavor in the rumen. The results showed:①The mixed fruit flavor meal could increase significantly the DM disappearance rate(P < 0.05), which resulted in increasing the dietary digestion and the feed coefficiency.②The effects of the mixed fruit flavor meal on the gas production, pH, NH3-N concentration, acetate, propionate, butyrate, TVFA and A/P ratio were not significant in the batch culture in vitro (P > 0.05), but could significantly increase the ruminal content of acetate, propionate, butyrate and TVFA (P < 0.05), and so did and the NH3-N concentration and A/P ratio (expect 0h) in vivo (P < 0.05).③According to avaluation of Multiple-Factors Associative Effects Index (MFAEI), the optimal supplemental dosage of the mixed fruit flavor meal was 7500g/t, the same as the result of the breeding trail.④Some flavor compounds of the mixed fruit flavor meal were found in the rumen liquid by SPME/GC-MS, including Acetic acid, 2-methylpropyl ester; 1-Butanol,3-methyl-, acetate; Butanoic acid, 2-methylpropyl este; Butanoic acid, ethyl ester; 1-Butanol,3-methyl-,propanoat; Propanoic acid, pentyl ester; Butanoic acid, 3-methylbutyl ester; and so on.⑵The metabolic changes of the mixed fruit flavor meal measured by the arterio-venous difference cross the mammary glandTwo cows with the permanent catheters at the external pudic artery and subcutaneous abdominal vein were fed a basal diet and used to investigate the metabolic changes of the mixed fruit flavor meal in the arterio-venous difference. The results showed that some flavor compounds of the mixed fruit flavor meal were measured in the external pudic artery and subcutaneous abdominal vein blood by PT-GCMS, and the flavor compounds content of the mixed fruit flavor meal in the external pudic artery were nearly 2～3 times in subcutaneous abdominal vein. The mammary uptake of flavor compounds was higher than the output from milk.⑶The effects of the mixed fruit flavor meal on the cell growth and cycle in the mammary epithelium cell culture and milk compositionThe mammary epithelial cells in the culture were home made, the dosage of the mixed fruit flavor meal 0, 5, 10, 15, 20 and 30μg/mL was added in the culture trail. The results showed:①The cell number and the cell proportion in S and G2/M period were the highest when the mixed fruit flavor meal dosage was 15μg/mL, but cell growth and cycle proliferation were stopped when the dosage was 30μg/mL.②These compounds from the mixed fruit flavor meal were found in the mammary culture liquid by PT-GCMS, and their levels were the highest when the dosage was 15μg/mL (P < 0.05).In conclusion, the above results indicated that the flavor compounds could improve the milk flavor and quality. The optimal supplemental dosage of the mixed fruit flavor meal was 7500g/t (DM basal of concentrate). The fruit flavor compounds in the added in the mixed fruit flavor meal changed in the different site of the lactating cow's body. some of the fruit flavor compounds were increased in ratio, some of compounds were decreased in qualitity, maybe some were disappeared in the animal body. Although the mixed fruit flavor meal could improve the milk flavor, the kind and ratio of the fruit flavor compounds in milk were changed.