On the relationship between chitin particle size and digestibility in the primate Galago senegalensis

Abstract

Experiments were performed to examine the relationship between the particle size of chitin and its digestibility in the small insectivorous prosimian Galago senegalensis. In the first set of experiments, four animals were fed a 25% chitin diet with the chitin particles less than or equal to 60mesh (0.250 mm maximum diameter). On average, the animals digested 22.5 -+ 2.2 percent of the ingested chitin. In the second set of experiments, the four animals were fed a 25% chitin diet with the chitin particles ground to S 4 0 -and 245-mesh (between 0.425 and 0.325 mm). On average, the animals digested 2.75 -t 1.38 percent of the ingested chitin. There was no significant variation between the performance of any of the animals on either the 60-or 40-45-mesh trials. In all instances, however, each animal digested significantly more of the 60-mesh chitin and the 40-45-mesh chitin.These experiments demonstrate the importance of masticatory efficiency among small mammals for improving the digestibility of foods such as insects which contain high proportions of chitin. They also suggest why insectivorous and folivorous primates have certain convergent dental specializations for finely grinding their foods. Both leaves and insects contain relatively indigestible structural carbohydrates. These substances are much more completely digested when the surface area to volume ratio of the swallowed material is increased. The masticatory efficiency of frugivorous primates is much lower since the constituents of these foods are relatively completely digested irrespective of the fineness of grinding.Recently, it has been shown that insectivorous primates masticate their foods more efficiently than do comparable sized frugivorous species (Sheine and Kay, '77). It was suggested that this provided more surface area for the action of digestive enzymes and enhanced the assimilation of chitin, a major component of insect exoskeletons. To confirm this hypothesis there must be evidence that there are chitinolytic enzymes in these species and that the digestibility of chitin increases as its surface-area to volume ratio is increased. The first of these requirements has been met. Beerton-Joly e t al. ('74) showed that there is a strong chitinolytic activity in the AM. J. PHYS, ANTHROP. (1979) 50: 301-308

Composition and Nutritional Characteristics of Fungi Consumed by Callimico goeldii in Pando, Bolivia

“…Chitin, the major component of insect exoskeletons, is also one of the primary constituents in the cell walls of fungi (Martin, 1979). High shearing crests on molar teeth increase their ability to break down the particle size of masticated food, thus increasing the surface area on which digestive enzymes or gut microbes can work and increasing the digestion rate of chitin (Kay and Sheine, 1979). Though this process has been considered only in the context of digesting the chitin in insect exoskeletons, it is reasonable to think that it would be similarly beneficial for the processing of chitin in fungi.…”

Primate digestion: Interactions among anatomy, physiology, and feeding ecology

“…Although it is probable that several primate species have the digestive enzyme chitinase in their digestive tracts, to date only a few primate species, among them Perodicticus potto and Galago senegalensis have been demonstrated to contain this enzyme. 59 Because it is a polysaccharide, chitin may also be broken down via microbial fermentation, which would explain why the virtually completely faunivorous tarsiers, as well as other primarily insectivorous prosimians, have extremely large caeca. 47,60 There is a broad association between an animal's gross gastrointestinal anatomy and what it eats.…”

The Effect of Canine Tooth Wear on the Diet of Big Brown Bats (Eptesicus fuscus)

“…-McArthur and Sanson, 1988). Larger particles yield a decreased surface area for enzymatic breakdown and thus lower an animal's ability to obtain energy from food (McLeod and Minson, 1969;Kay and Sheine, 1979). Thus, tooth wear may influence the amount of energy available to insectivorous bats during the later stages in life.…”