Page 1170 - Small Animal Clinical Nutrition 5th Edition

1220 Small Animal Clinical Nutrition

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Figure 70-2. A ventrodorsal radiograph of the abdomen of a rabbit Figure 70-3. A ventrodorsal radiograph of the abdomen of the rabbit
with a gastric trichobezoar. Note the tubular distention of the stom- in Figure 70-2 following a barium swallow. Note the contrast medium
ach. (Reprinted with permission from Veterinary Medicine 1995; 90: outlining the mass filling the gastric lumen. (Reprinted with permis-
365-372.) sion from Veterinary Medicine 1995; 90: 365-372.)

a spiral structure and the largest and most prominent organ in and particles retrograde through the colon into the cecum for
the abdominal cavity of rabbits. The cecum has approximately fermentation. After fermentation, the cecal contents are ex-
10-fold the stomach capacity and makes up 40 to 60% of the pelled through the colon (Brooks, 2004; Cheeke, 1994; Jenkins,
total volume of the GI tract (Jenkins, 1999). Antiperistaltic 1999; Irelbeck, 2001). The fermented pellets produced in the
action moves small particles and solubles into the cecum, where cecum are called cecotrophs. Cecotrophs are excreted during
cellulose is digested and fermented. The GI transit time for the night and early morning, approximately eight hours after
fiber is approximately four to five hours. consumption of the original food item, as clusters of grapelike
Instead of chewing cud for improved digestion, as would material and are consumed (cecotrophy) directly from the anus.
ruminants, rabbits use cecotrophy or pseudorumination Cecotrophs contain twice the protein (25 to 30% DM) of usual
(Brooks, 2004). Muscular contractions in the colon cause indi- fecal pellets, more B vitamins and much less fiber (Tobin, 1996;
gestible fiber particles to separate from nonfiber components of Lowe, 1998; Brooks, 2004; Davies and Davies, 2003). Ceco-
the gut contents. The fusus coli, another structure unique to trophy is particularly important for efficient digestion of forage
lagomorphs, separates the proximal from the distal colon. The proteins. The process also provides the rabbit with microbially
fusus coli functions as a pacemaker to control colonic contrac- synthesized B-complex vitamins, microbial protein and small
tions. Peristaltic contractions move fiber through the colon for quantities of volatile fatty acids. The pH of the rabbit’s stom-
excretion in hard feces. Antiperistaltic contractions move fluids ach is extremely acidic (<2.0), which may neutralize large num-