Effects of cecectomy on digestion and retention time of digesta in rats

Abstract

ABSTRACTThe present experiment aimed to obtain basic knowledge of the role of the cecum in the digestion of protein, fiber and energy, and in the retention of digesta in rats. Twelve healthy male Sprague–Dawley strain rats were used. The experiment lasted for 8 weeks following preliminary feeding. Crude protein [CP], acid detergent fiber [ADF], and energy digestibilities were measured in weeks 1, 4, and 7 of the experiment, while the digesta retention time was measured in weeks 2, 5, and 8. At the end of the test, the colon capacity was measured after killing the rats with diethyl ether. The effects of the cecectomy were not recognized in bodyweight gain, even while the feed intake was high and the feed efficiency was low due to the cecectomy. However these effects were not recognized in the latter half of the test periods. The mean retention time of digesta for the cecectomized rats was about 2 h shorter than that for the control group of rats, while the retention time of digesta in week 8 increased compared to weeks 2 and 5. The digestibility of each substance was significantly lower following the cecectomy. The colon became swollen because of the cecectomy and this swollen colon made up for the capacity of the dissected cecum. It had been considered that the cecum does not play a role in the digestion of nutrition for growth, however, the present results showed two types of effects of cecectomy: one that disappears in accordance with time after surgery (i.e. feed intake and feed efficiency), and another that continues for a longer period (i.e. digestibility, retention time of digesta).