4. Discussion
Our objective was to evaluate the effects of adding AOAN on nutrient digestibility
of a TMR and three roughages (corn silage, oat hay, and alfalfa hay) typical of those given
to dairy cows in China by analyzing fermentation parameters and bacterial composition
(Supplemental Figure S1).
NDF digestibility after 30 h of incubation and starch digestibility after 7 h of incuba-
tion were related to the value and quality of feed [37,38]. AOAN significantly improved
nutrient utilization and digestion. Several studies have examined the A. oryzae product,
Amaferm, and have indicated that Amaferm increased NDF digestibility of switchgrass
and bromegrass at 12 h [39], alfalfa hay at 48 h [40], and DM digestibility of a TMR at 24
h in vitro [41]. Positive results from the animal experiment also indicated that DM and CP
digestibility were increased by Amaferm supplementation [42], and fiber digestibility of
the rumen and total tract were improved [43]. Our results are consistent with these stud-
ies. However, the inconsistent results from Sievert et al. [17], who indicated that total tract
digestibility was not changed and milk fat was depressed by Amaferm. Lactation cows
are different from dry cows, which might partly explain the divergent results. Further-
more, a recent study reported that the percentage and types of roughage used could in-
fluence this response [13]. Many reasons may contribute to this response, including dif-
ferent strains used in fermentation or unique chemical linkages in the roughage [10,44].
Therefore, we used an extract from A. oryzae combined with A. niger to improve the use
of fungal extracts. Although the results obtained by in vitro techniques cannot completely
reflect or replace those obtained from in vivo studies. The results of the present study
provide important insights into the efficacy of AOAN.
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