Volume 120, Issue 1, July 2014, Pages 42–50
Abstract
The objectives of this study were to evaluate the effect of oak fruit (Quercus persica)
in the diet of sheep with and without polyethylene glycol (PEG) on
nutrients digestibility, rumen fermentation parameters, protozoal count
and microbial protein supply. In Exp. 1, five fistulated mature male
sheep were used in a 5 × 5 Latin square design, with 5 dietary
treatments arranged in a 2 × 2 + 1 factorial: (1) control as a basal
diet; (2) control plus 10% oak acorn (OA); (3) control plus 30% OA; (4)
control plus 10% OA with 100 g PEG; and (5) control plus 30% OA with
100 g PEG. Incorporation of OA decreased digestible organic matter
(DOM), digestible crude protein (DCP) and digestible neutral detergent
fiber (DNDF) and the lowest values were observed at the level of 30% OA.
However, administration of PEG to the diets overcame deleterious effect
of acorn on these parameters, significantly (P < 0.01).
With the addition of OA a noticeable decrease in ammonia and TVFA
concentration was observed and adding PEG to the diets increased these
values even higher than those of control (P < 0.01).
Incorporation of acorn to the diets lowered urinary purine derivatives
(PD) and urinary, retained and absorbed nitrogen and increased fecal and
endogenous nitrogen (P < 0.01). Meanwhile, addition of PEG
increased PD and urinary, retained and absorbed nitrogen and decreased
fecal and endogenous nitrogen. Total protozoa content was affected in
somewhat by OA and PEG supplementation. Isotricha, dasytricha and,
diplodinium contents did not differ due to inclusion of OA, however, the
trend for entodinium and ophryoscolex was to be decreased (P < 0.05).
There was a significant effect on individual genera of protozoa
following addition of PEG to the diets. Cellulolytic and proteolytic
bacteria were not influenced by incorporation of OA but the trend was in
decreasing manor. In Exp. 2, in vitro gas production was conducted to
evaluate kinetics of gas produced by diets. The parameter “A” did not
differ among experimental treatments. Half-time of gas production in
control group was higher than that of other treatments. Methane
production from diets containing OA and PEG were lower than that of
control group. In conclusion, supplementation of OA with PEG may be a
practical approach to overcome detrimental effects of tannins in this
feedstuff.
Keywords
- Oak acorn;
- Protozoa;
- Cellulolytic bacteria;
- Tannin
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