The Stimulatory Effect of Sodium Butyrate and Sodium Propionate on the Development of Rumen Mucosa in the Young Calf

Twelve young' dairy calves equipped with rumen eannulae were fed milk aad housed in tie stalls with elevated floors to prevent bedding consumption.Sodimn acetate, sodium propionate, sodium butyrate, sodium chloride, and glucose were administered over an /1-wk.period, to study their effect ou ramen mueosa!development.Two calves served as controls.Administration of solutions of sodium butyrate or sodium propionate caused marked development of the rumen mueosa, whereas the other materials caused relatively little growth.It is hypothesized that the growth of rumen papillae is probably a result of the metabolism of certain compounds by the rumen wall and/or their effect on blood flow in the rumen.The newborn ruminant has a forestomach that is rudimentary both anatomically and physiologically.Contrary to early beliefs, the stimulus necessary to develop the forestoma('h tissues of young ruminants does not come entirely from the physical nature of the feed.Flatt ct al. (7) reported that a low-fiber purified diet or a solution of the mixed sodium salts of acetic, propionie, butyric, and lactic acids caused the developnwnt of rumen papillae; whereas, coarse, inert materials, such as plastic sponges, were ineffective.The biochemical or physiological basis for the growth of rmnen papillae following contact with the volatile fatty acids or a fermenting low-fiber diet is not clear.In these experiments, stimulation of papillary growth using several pure, absorbable, and/or nietabolizable compounds was measured. EXI'EI{IM EIVq'A[J I'ROCEI) (ri¢EExperimental animals.Twelve grade Holstein bull calves tmrt'hased at local auetions were fitted with eannula-type rumen fistnlae (inside diameter a~ ill.) at 2 to 5 wk. of age, aceordillg to the method of Dougherty (4).They were confined ia tic stalls equipped with elevated wooden platforms to prevent bedding consunlption, and fed whole milk from nipple pails.The amo'unt of milk fed was adjnsted periodically in an attempt to keep the rate of gain uniform.Iodized salt and water were available free-choice.A mineral supplement and vitamin l) were provided as previously reported (Warner et al., 19).The calves were weighed weekly and records of feed consumption were kept.l'reatme,nts.In addition to tile basal milk allo~Inent, eight of tile calves were given a solution of either sodium acetate, propionate, butyrate, or chloride; and two were given a glucose solution via rmnen cammlae.Two calves were randomly assigned to each treatment and two control calves received only milk.Stock solutions of the sodium salts of the fatty acids were prepared, using analytit, al-grade reagents (Table I), so that one liter o[ the solution contained an