| This study was aimed at the lack of data support and practical reference for scientific formulation of liquid diet in pasture,the study was performed to investigate the effects of feeding acidified milk powder on growth performance,blood immunity index and fecal microorganism diversity of calves.This paper was aimed at providing theoretical support and practical reference for utilization of acidified milk powder in large scale dairy farm.(1)Comparison of Nutrient Composition,p H Value and Microorganism Quantity of Acidified Milk Powder,Pasteurized Milk Powder and Acidified MilkThe experiment uses milk powder as the raw material,after formic acid acidification and pasteurization treatment,it is compared with acidified milk.The results showed that the content of lactose in pasteurized milk powder(PP)group and acidified milk(AM)group was significantly higher than that in acidified milk powder(AP)group(P<0.05),the content of total solid in AM group was significantly higher than that in AP group(P<0.05),and the content of urea nitrogen in AM group was significantly higher than that in AP group and PP group(P<0.01),The p H value,total bacterial count and Escherichia coli count of PP group were significantly higher than those of AP group and AM group(P<0.01).(2)Effects of Acidified Milk Powder,Pasteurized Milk Powder and Acidified Milk on the Growth Performance of CalvesComplete randomized design was adopted in this experiment.A total of 27 healthy30-day-old Holstein calves with a similar body weight were randomly divided into 3 groups with9 calves per group,namely acidified milk powder group(AP group),pasteurized milk powder group(PP group)and acidified milk group(AM group).Calves were weaned at 70 days old,fed to 180 days,and the experiment period was 150 days.The intake of liquid,solid diets was recorded.Body weight,body measurements were measured.Simultaneously,average daily gain,body measurements index were calculated.The feces were scored daily before 70 days old and the diarrhea rate was calculated.The results showed that when the calves were at age 30~40 days,the intake of liquid diet in AM group was significantly higher than that in AP group and PP group(P<0.01).At 51~60 days,that in AM group was significantly lower than that in AP group and in PP group(P<0.05,P<0.01);The intake of solid diet in AP group and AM group wassignificantly higher than that in PP group at 71~120 days(P<0.05),the intake of AM group was significantly higher than that in PP group at 121~180 days(P<0.05).Compared with AM group,the calf body weight of AP group and PP group increased significantly at 60 days(P<0.01).Compared with PP group,the calf body weight of AP group and AM group increased significantly at 90 days and 120 days(P<0.05),and the calf body weight of AP group increased significantly at 180 days(P<0.05);The daily gain of calves in AP group and PP group was significantly higher than that in AM group during 30 to 60 days(P<0.05).The daily gain of calves in AP group and AM group was significantly higher than that in PP group during 71 to180 days and 30 to 180 days(P<0.05,P<0.01).At 30 days,the difference of body measurement index were no significant.Compared with AM group,the body straight length and chest circumference of calves at 60 days,chest circumference,chest depth,body length index and leg circumference index at 70 days and body oblique length at 120 days and 180 days in AP group and PP group were significantly increased(P<0.05,P<0.01).The chest depth of AP group at 60 days,leg circumference at 70 days and 90 days,and bone circumference and bone circumference index at 120 days were significantly increased(P<0.05,P<0.01).The bone circumference index of PP group at 60 days and 180 days,bone circumference index and chest circumference index at90 days and body length index of 120 days were significantly increased(P<0.05,P<0.01).Compared with PP group,the body height of AP group and AM group at 70 days,the body height and body straight length at 90 days,chest circumference index at 120 days and the body height,chest circumference,chest depth and chest circumference index at 180 days were significantly increased(P<0.05,P<0.01).The body height of AP group at 60 days,the body height,chest circumference and chest depth at 120 days and body straight length at 180 days,and the limb length index at 90 days,body index at 120 days and 180 days in AM group were significantly increased(P<0.05,P<0.01).Compared with PP group and AM group,leg circumference at 60 days,body straight length at 70 days and body oblique length,chest circumference and chest depth at 90 days in AP group were significantly increased(P<0.05,P<0.01).There was no significant difference in fecal score of the three groups between 51 and60 days.The fecal score of AP group was significantly lower than that of PP group and AM group at 61~70 days(P<0.01).Compared with PP group,the feces of AP group and AM group whose scores and diarrhea rates were significantly decreased at other time periods(P<0.01).(3)Effects of Acidified Milk Powder,Pasteurized Milk Powder and Acidified Milk on Blood Immune Indices of CalvesBlood samples were collected at 30,60,70,90,120 and 180 days before morning feeding.The contents of routine and immune indexes in blood were measured.The results showed that,compared with AP group and AM group,the WBC,LYM and IL-1? contents of calves in PP group at 60 days,the WBC,IL-6 and TNF-? contents of calves at 70 days were significantly increased(P<0.05,P<0.01),and the contents of Ig G and Ig M at 60 days,Ig M and IL-1? at 70 days and IL-1? at 90 days in PP group were significantly decreased(P<0.05,P<0.01).At 70 days,compared with PP group,the Ig G and IL-1? contents of calves in AP group were significantly increased(P<0.05),LYM and TNF-? levels in AP group,and TNF-? levels in AM group at 90 days were significantly decreased(P<0.05,P<0.01).Compared with AM group,the LYM content of AP group was significantly decreased at 70 days(P<0.01);there were no significant results at other time points.(4)Effects of Acidified Milk Powder,Pasteurized Milk Powder and Acidified Milk on the Fecal Microbes Diversity of CalvesOn the 50 th,70th and 90 th day of calf growth,three calves with similar body conditions were selected from each group,and about 20 g of rectal end feces were scraped for 16 sr DNA amplification and sequencing.The experimental results show that 1,468,772 high quality sequences have been obtained for subsequent analysis.OTU cluster analysis showed that 1297 OTUs were distributed in 15 phyla,28 classes,53 orders,87 families and 245 genera.The results of Alpha diversity index analysis showed that the Shannon index,ace index and Chao index of Alpha diversity index increased gradually with the calf age increasing,while the Simpson index decreased gradually with the calf age increasing.Except for 50 days,the Shannon index AP >PP > AM,and the other two time points,the Shannon index AP > AM > PP.Ace index and Chao index do not show specific rules.Species composition analysis result showed that Firmicutes,Bacteroidetes and Proteobacteria were the most abundant species in the 9 groups.LEf Se analysis showed that there were 13 microbial communities in AP group,which were significantly more than 6 in PP group and 8 in AM group.To summarize,the milk composition of acidified milk powder has been improved,meanwhile that can effectively control the growth of detrimental bacteria;it can improve calf'sintake,reduce diarrhea rate,and contribute healthy growth and development to calf;improve calf immunity,enhance immune function;it can affect the diversity of microorganisms in calf feces,and has a certain regulatory effect on intestinal flora. |
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