The gastrointestinal tract of the rock hyrax (Procavia habessinica). 2. Fluid flow, production of short chain fatty acids and absorption of water and electrolytes.

In the digestive tract of the rock hyrax (Procavia habessinica), water is absorbed from the small intestine and from the wider part of the connecting colon running between the caecum and the colonic sac. Only little water absorption occurs from these two fermenting chambers. The outflow from the caecum is much higher than from the colonic sac mainly due to the effective absorption in the connecting colon with its very large absorptive area. A significant lower osmolality was found in the caecal contents compared with the contents in the colonic sac. The Na/K ratio was 10.7 and 1.7, respectively in these sections. Short chain fatty acids are produced at a rate of nearly 10 mmol/100 ml/hr in the contents of both the caecum and the colonic sac. The results are discussed in relation to the findings in domestic and laboratory animals.

Retrograde flow of urine from cloaca to caeca in laying hens in relation to different levels of nitrogen intake.

Retrograde flow of urine into the caeca provides a more efficient recovery of nutrients and supplies a nitrogen source for the caecal microbes. 30 laying hens of Leghorn type were used in the present experiments. Hens were randomly divided into three treatment groups and fed a high nitrogen (19.8% crude protein in dry matter), medium (15.0% crude protein in dry matter), or low (10.6% crude protein in dry matter) isocaloric diet for fourteen days prior to and during the experimental period (8 h). Results from the study show that the retrograde flow of urine from cloaca to caeca is significantly higher in birds given a low protein diet compared to medium or high levels. It also shows that the produced amount of urine is significantly higher in hens given a low protein diet compared to the medium level diet.

Clinical changes in ovariectomized ewes exposed to phytoestrogens and 17 beta-estradiol implants.

Eight Swedish Finewool Landrace ewes, ovariectomized 5 months earlier and kept on nonestrogenic hay, were each fed 3.5 kg red clover silage, corresponding to 6.1 g phytoestrogens (of which 3.5 g was formononetin) per day, for 14 days in November (short days). In January (short days), two groups (3 each) of these ewes received one or two 17 beta-estradiol sc implants. In May (long days), one of two new groups (4 each) of these ewes was reexposed to phytoestrogens for another 14 days while the other served as a control. Physical examination of ewes for changes in reproductive organs was carried out two or three times per week during each feeding/treatment, and continued until observed changes disappeared. Clinically significant changes occurred in the reproductive organs of ewes fed red clover. Vulva color changed from pale to pink and red, and there were enlargements of the vulva, uterus, and udder. In addition, teat length and circumference increased, and secretion of milky fluid began. These changes were similar, but more pronounced during treatment with 17 beta-estradiol, particularly teat circumference. The changes in vulva were more dramatic in May than in November and resembled those observed in ewes treated with estradiol. Our data show that a daily intake of 3.5 g formononetin for 14 days caused the increase of teat size and changes in the color of the vulva and in uterus weight in ovariectomized ewes.

The gastrointestinal tract of the rock hyrax (Procavia habessinica). 1. Morphology and motility patterns of the tract.

The stomach of the rock hyrax (Procavia habessinica) is divided into a non glandular part with very slow movements, and a glandular part which rapidly mix the digesta. The large intestine has two fermentation chambers, the caecum, which rapidly mixes the digesta, and the colonic sac, which efficiently, but slowly, mixes digesta. Between these chambers runs the connecting colon. No retrograde transport is observed in any part of the large intestine.

The significance of water absorption and fibre digestion in the omasum of sheep, goats and cattle.

1. The omasal dry matter contents constituted 0.6, 1.2 and 3.3% of the body weight in the sheep, goats and cows, respectively. 2. A large part of the fluid leaving the reticulo-rumen passed quickly through or along the omasum to the abomasum in sheep (43%). The proportion was much less in goats (17%). 3. The absorption of water from the fluid delayed in the omasum was low: 15, 18 and 19% in sheep, goats and cows, respectively. 4. Little or no acid detergent fibre was degraded in the omasum.

Regional differences in hindgut structure and function in the nutria, Myocastor coypus.

Morphologically the large intestine of the nutria resembles that of other caviomorphs, notably the guinea pig. The cecum is voluminous: it contributes 8.6% of the total intestinal length and 12.7% of the total intestinal surface area (considering the surface enlargement factor). It contains 27-32% of the wet ingesta and 20-23% of the dry matter in the gastrointestinal tract. In the colon the corresponding figures are: 21.8% of length, 12.6% of surface area, 16-21% of wet ingesta, and 16-40% of dry matter. The colon can be subdivided both structurally and functionally into two sections, the proximal and the distal colon, the border between the two being the apical flexure of a long parallel loop. The proximal colon (42% of colonic length) displays on the mucosal surface of its mesenterial side a narrow furrow bordered by ridges, which is absent in the distal colon. The ridges contain subepithelial accumulations of coiled tubuloalveolar mucoid glands, entwined by bundles of muscle fibers. Determinations of nitrogen in the contents near the furrow suggest a concentration of bacteria in this part of the lumen. It is hypothesized that the structural differentiations of the proximal colon provide mechanisms for the transport of bacteria from the proximal colon back into the cecum to maintain the fermentation function. The slopes of the longitudinal profiles for dry matter and for concentrations of sodium, potassium and calcium in the luminal contents change at the tip of the parallel loop. The electrical potential difference "intestinal lumen - blood" is particularly large in the proximal colon, indicating active electrogenic ion transport in this region.

The colonic separation mechanism in the guinea-pig (Cavia porcellus) and the chinchilla (Chinchilla laniger).

In guinea-pig, the concentration of nitrogen and viable bacteria were nearly twice as high in the contents of the colonic furrow compared to the contents of the corresponding lumen. Labelled bacteria infused into the proximal colon of guinea-pigs were transported in the furrow into the caecum. Both species produced two types of pellets, one nitrogen-rich intended for caecotrophy, and one nitrogen-poor delivered as faecal pellets. The furrow is part of a separation mechanism in both species saving bacteria for the animals.