STUDIES ON OCCURRENCE OF MYCOBACTERIUM AVIUM SUBSPECIES PARATUBERCULOSIS IN BOVINE WITH REFERENCE TO SEROLOGICAL AND MOLECULAR DIAGNOSIS
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Date
2006
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DUVASU
Abstract
naerobic fungi were found in the rumen of
sheep fed a tropical hay, and they appeared to
contribute to digestion when there was adequate
dietary sulfur (Akin et al. 1983). In a study of
sulfur-deficient wheat straw fed to a sheeo. Gordon
et al. ( 1983) showed thar rwo typei of anaerobic
fungi were present in the rumen. In culture,
one fungus produced an obvious mycelium
and resembled Neocallimasti frontalis (Orpin
1975), whereas the other produced a sporangium
from "spherical bodies" and resembled Spftaeromonas
communis (Orpin 1976). The straw diet
did not support normal populations of these
fungi. However, dietary methionine supplementation
allowed the proliferation of the mycelial
type (MT) but not the non-mycelial type (NMT)
(Gordon et al. 1983). We now report the in vitro
digestion of milled wheat straw by these fungi.
Two cultures of each fungal type were isolated
(Joblin 198I) from antibiotic-containing
agar ro11 tubes of medium-l0 (Caldwell and
Bryant 1966), with added 0.05% xyian, and dispensed
under CO, into Hungate culture tubes
(Bellco, Vineland, N.J. USA). The isolates were
maintained at 39"C in broths by transfer into
fresh medium every 34 days. Culture tubes
containing 0.25 g air-dried, milled (< I mm)
wheat straw and 10 mL basal medium-lO (as
above, but no added carbohydrates or antibiotics)
were autoclaved at 1 1 0 KPa for 15 min. For
each isolate, 16 tubes were separately inoculated
with 0.5 mL of a well-brown broth culture. The
residues remaining after incubation at 39"C for
4 days (MT-1 and -2) or 5 days (NMT-1 and -2)
were analyzed in quadruplicate for organic matter,
neutral detergent fiber (NDF), acid detergent
fiber (ADF), permanganate cellulose and
permanganate-oxidized lignin by adapting exCan.
J. Anim. Sci. 64 (Suppl.): 156-157 (Sept. 1984)
isting methods (Goering and Van Soest 1970) to
semi-micro crucibles (10 mL capacity; Filtrex,
Moorooka, Queensiand, Aust.). The analytical
data for each fungus were compared with identically
analyzed wheat straw from uninoculated
culture tubes.
The milled wheat straw used in this study was
composed of 92.9Vo dry matter and, on a dry
matter basis, 96.6Vo organic matter,80.7Vo
NDF, 52.6% ADF , 43 .57o cellulose and 17 .3Vo
lignin. The results of the in vitro digestion of
straw components by both MT and NMT fungi
are shown in Table 1. Much more organic matter,
NDF, ADF and cellulose fractions were digested
by the MT fungi. However, very little, if
any, of the lignin component was solubilized
after incubation with either of the fungal types.
The in vitro digestion of fiber by anaerobic
fungi confirmed the role played by these microorganisms
in the overall digestion of dietary
plant fiber in the rumen. The quantities of fiber
fractions digested from straw are considerably
less than those digested from grass hay reported
for similar fungi by Orpin (1981). These differences
in digestion are particularly large for the
NMT fungi, and could be due either to the different
source of fibers used or to the different
analytical methods. As suggested by Orpin
(1976) the inability of NMT fungi to produce a
filamentous mycelium may be an artefact of
growth in culture. However, the effect that possession
of "spherical bodies" may have on the
degradative ability of these fungi remains unknown.
The response to dietary methionine by MT
fungi in the rumen (Gordon et al. 1983) suggests
that these fu
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