Probiótico fúngico para ovinos alimentados com dietas de alto grão
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2019-09-04
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Universidade Federal de Goiás
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The objective was to select facultative anaerobic fungi from the sheep rumen
and to evaluate their probiotic capacity in association with high grain diets
(DAG) for Santa Inês/Dorper sheep. It was obtained 30 fungal isolates from
the sheep rumen submitted to DAG, which were part of the fungal collection
stored in the Laboratory of Microbiology of the Federal Goiano Campus Ceres
Institute, where the in vitro and in vivo assay was also conducted. The
isolates were classified according to morphotyping by microculture, submitted
to amylase and mycotoxin enzyme production tests, tolerance to the main
volatile fatty acids, viability in the ruminal fluid and the colonization capacity
of the starch granules. In the performance test, 4x2 factorial was used in CED,
with four inoculants (no inoculum, Rhizomucor spp., Aspergillus terreus and
mixed of two fungi) and two processing (ground or whole grain). Eight bays
with five lambs/bay were used for 75 days with 15 days of adaptation. The
diets with 85% corn plus 15% vitamin, mineral and protein nucleus were fed
ad libtum twice a day (7h and 16h), allowed to be left over 5%, and the
inocula sprinkled at the time of feeding. Five samples were taken of the
ingredients of the diets, the diets and the leftovers of the diets during the test
to perform the centesimal analyzes. The animals were weighed biweekly for
evaluation of performance indices. At the end of the trial, the carcass yields of
five animals per treatment were calculated, as well as the ruminal fluid for the
study of the microbiological profile of the rumen, macroscopic evaluation of
the ruminal liquid, ammonia nitrogen concentration and microbiological
activity, in addition to the TGI fragments for histological analysis. The
parametric data were submitted to ANOVA and the data averages compared
by the Tukey test at 5%. For the variables of the microbiological profile, the
non-parametric tests, Chi-square test, Wilcoxon and Kruscall-Wallis were
used, besides the descriptive analyzes. Of the 30 selected fungal isolates, 21
are of the genus Aspergillus, six of the genus Rhizopus spp. and three
Rhizomucor spp. which were evaluated for their probiotic potential in vitro. All
the isolates were able to degrade starch, and 19 are mycotoxin producers,
being initially not feasible as a probiotic. There was no interaction between
probiotic and processing factors for the performance variables (P>0.05), nor
was there any effect of the addition of probiotics on the performance of sheep
fed the different treatments (P> 0.05). Greater consumption of DM, MM, EE,
NDF and CNF was observed for animals fed whole grain corn (MGI) (P<0.05).
There was no significant difference (P>0.05) for OM, PB, GPMD, CA and
neither for food efficiency. Fluid staining showed a low rate of acidosis. The
aromatic odor predominated, which characterizes environment with neutral
pH. Fluid samples showed high microbial activity. The ruminal pH differed
(P<0.05) when considered the type of processing, being higher for milled
grain (MGM). No difference was observed in any of the analyzed
microbiological communities (P>0.05) (Lac + and Lac- bacteria, fungi, yeasts
and protozoa). Six genera of facultative anaerobic fungi were identified for all
ruminal fluid samples from a total of 15 observations. Cladosporium spp. was
the most prevalent genus (46.66%), followed by Aspergillus (26.66%). There
was no significant difference in the protozoan population (P>0.05). The width
of the base of the papillae presented expressive interaction between the
fungal probiotic and processing factors, being higher for MGM (P<0.05) for
Rhizomucor spp. treatment and control (P<0.05). Selected anaerobic fungi
from the rumen are promising to be used as a probiotic on a high grain diet,
however in the performance assay the increased fungi concentration has not
been shown to be effective. Other studies are necessary to find the
appropriate situation for maximum productive expression of the isolated
selected fungi.
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FABINO NETO, Ronaildo. Probiótico fúngico para ovinos alimentados com dietas de alto grão. 2019. 82 f.
Dissertação (Mestrado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2019.