DEVELOPMENT OF BUFFER SYSTEMS FOR PH CONTROL AND EVALUATION OF PH EFFECTS ON FIBER DIGESTION INVITRO

被引:47
作者
GRANT, RJ [1 ]
MERTENS, DR [1 ]
机构
[1] USDA ARS,US DAIRY FORAGE RES CTR,MADISON,WI 53719
关键词
FIBER; ARTIFICIAL RUMEN; CITRATE; PHOSPHATE-BICARBONATE;
D O I
10.3168/jds.S0022-0302(92)77915-6
中图分类号
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号
0905 ;
摘要
An in vitro buffering system capable of pH control between pH 5.8 and 6.8 was developed to examine the effect of media pH on disappearance of NDF at various times of fermentation and to assess initially the effect of media pH on kinetics of NDF digestion. The pH conditions selected for evaluation of these buffer systems were 5.8, 6.2, and 6.8. Use of McIlvaine's solution with sodium bicarbonate was not successful because of rapid drifting of pH downward during fermentation. To evaluate the effectiveness of citric or phosphoric acids as components of phosphate bicarbonate buffer systems, alfalfa silage and a mixture of alfalfa silage and com grain (1:1 mixture, dry basis) were fermented for 0, 12, 24, 48, and 72 h. The pH of each flask was measured at 0, 4, 12, 24, 48, and 72 h postinoculation, and pH was readjusted with bicarbonate solution when necessary. Drifting of media pH downward was more noticeable when phosphoric acid was used to adjust the buffer pH than with citric acid. Citric acid had no adverse effects on NDF digestion compared with phosphoric acid when used to adjust a phosphate-bicarbonate buffer system. Alfalfa hay, bromegrass hay, and com silage were incubated for 0, 12, 24, 48, 72, or 96 h at pH 5.8 or 6.8 using the phosphate-bicarbonate buffer system adjusted with citric acid. Estimation of kinetics of NDF digestion indicated that a decrease in media pH from 6.8 to 5.8 resulted in a marked reduction in NDF digestion; the largest apparent difference was digestion lag time.
引用
收藏
页码:1581 / 1587
页数:7
相关论文
共 16 条
[1]  
ELSHAZLY K, 1961, J ANIM SCI, V20, P268
[2]   PREPARATION OF BUFFER SYSTEMS OF CONSTANT IONIC STRENGTH [J].
ELVING, PJ ;
MARKOWITZ, JM ;
ROSENTHAL, I .
ANALYTICAL CHEMISTRY, 1956, 28 (07) :1179-1180
[3]  
GOERING HK, 1970, AGR HDB ARS USDA, V379
[4]   HYDROGEN ION BUFFERS FOR BIOLOGICAL RESEARCH [J].
GOOD, NE ;
WINGET, GD ;
WINTER, W ;
CONNOLLY, TN ;
IZAWA, S ;
SINGH, RMM .
BIOCHEMISTRY, 1966, 5 (02) :467-&
[5]  
HOOVER WH, 1984, J ANIM SCI, V58, P692
[6]  
Mertens D. R., 1973, THESIS CORNELL U ITH
[7]   THE EFFECT OF STARCH ON FORAGE FIBER DIGESTION KINETICS INVITRO [J].
MERTENS, DR ;
LOFTEN, JR .
JOURNAL OF DAIRY SCIENCE, 1980, 63 (09) :1437-1446
[8]  
MERTENS DR, 1977, FED PROC, V36, P187
[9]  
ORSKOV ER, 1975, BRIT J NUTR, V34, P493
[10]   INFLUENCE OF DECLINING LEVEL OF FEED-INTAKE AND VARYING THE PROPORTION OF STARCH IN THE CONCENTRATE ON RUMEN FERMENTATION IN DAIRY-COWS [J].
ROBINSON, PH ;
TAMMINGA, S ;
VANVUUREN, AM .
LIVESTOCK PRODUCTION SCIENCE, 1986, 15 (02) :173-189