Control of the ruminal pH depression produced during the concentrate feeding - The possibility of the increase in a saliva secretion by the mechanical stimulus to the ruminal wall

研究了在精料饲养过程中，添加机械刺激对反刍动物瘤胃唾液分泌、瘤胃网运动和消化特性的影响。将瘤胃添加机械刺激的+Stim条件与对照条件（-Stim）进行比较。两组每天瘤胃网收缩次数无显著差异。然而，在+Stim条件下，反刍进入初级循环的速度显著增加。特别是从午夜到凌晨，反刍次数增加。每天唾液分泌量在+Stim条件下有增加的趋势。在+Stim条件下，饲喂时的增幅大于-Stim条件。+Stim条件下1天内瘤胃pH值波动幅度较小。特别是饲喂开始后的pH下降速率明显小于-Stim条件。+Stim条件下瘤胃总VFA浓度显著升高，干物质消化率+Stim条件下瘤胃干草消化率低，精料消化率高。饲喂精料的反刍动物对瘤胃的机械刺激刺激了瘤胃网膜的机械受体。虽然机械刺激不改变反刍网运动的次数，但反刍率增加。因此，我们认为，这可能导致唾液分泌量的增加和胃内pH值的稳定，并最终导致前胃发酵能力的改善和消化速度的提高。

The influence which the mechanical stimulus added into the ruminoreticulum of a ruminant has on the saliva secretion, the ruminoreticulum motility, and the nature of digestion in a rumen during concentrate fed was investigated.The +Stim conditions which added the mechanical stimulus to the rumen were compared with the control conditions (-Stim).There was no significant difference in the number of ruminoreticulum contraction per day. However the rate of the rumination to a primary cycle increased significantly on +Stim conditions. Especially, the number of ruminations increased from the midnight to early morning. The amount of saliva secretions per day showed the tendency which increases on +Stim conditions. The increase at the time of a feeding was larger than -Stim conditions on +Stim conditions. The range of fluctuation within a day of a ruminal pH was small on +Stim conditions.Especially, pH depression rate after feeding start was significantly smaller than -Stim conditions. The total VFA concentration in a rumen became high significantly on +Stim conditions, the rate of the dry-matter digestion in a rumen in +Stim conditions had the low rate of hay digestion, and its rate of concentrate digestion was high. The mechanical stimulus to the rumen given to the ruminant fed in the concentrate stimulated the mechano-receptor in a ruminoreticulum. The rate of a rumination was made to increase although a mechanical stimulus does not change the number of ruminoreticulum movements. Consequently, it was suggested that the increase in the amount of saliva secretions and the stability of pH in the stomach may be caused, and the improvement in the fermentability in a forestomach and the improvement in the rate of digestion may finally be caused.