3.2.2. Intestinal epithelium histology
The dietary replacement levels of the SO with RO showed
a quadratic effect (Pb0.01) on villus width and a cubic effect
(Pb0.01) on villus height:crypt depth ratio in the duodenum
(Table 6). Other variables of the intestinal epithelium histology
were not affected (P>0.05) by the dietary replacement
levels of SO with RO (Table 6). There are some indications
that there is an ideal dietary proportion of fatty acids to
meet enterocytes requirements exists (Lauridsen, 2010; Li
et al., 1990). Thus, the mix of SO and RO may have resulted
in a different proportion of fatty acids than those required
by the enterocytes, modifying the villus width (Table 6).
However, a biological explanation for a cubic effect of dietary
replacement levels of oils on the villus height:crypt depth
ratio in the duodenum of weanling pigs (Table 6) was not
found.
3.2.3. Organ morphometry
The relative weight of the digestive organs and the spleen
was not influenced (P>0.05) by a dietary replacement of SO
with RO (data not shown), which may indicate that the RO
did not alter the metabolism. Studies comparing organ morphometry
of animals supplemented with rice oil were not
found in the literature.
3.2.4. Occurrence of diarrhea
No effects (P>0.05) of the dietary replacement levels of
SO with RO were observed in the occurrence of diarrhea
(data not shown). These results were similar to those found
by Lima et al. (2009) with weanling pigs and by Sierra et al.
(2005) with rats.
Regardless of the replacement levels, for 1 to 7 days and 1
to 14 days of experiment, the average of PAD were 46.67 and
59.17%, respectively. No diarrhea was observed after the 14th
day of the experiment, which indicates that the critical period
for the pigs is the two first weeks after weaning.
4. Implications
If the experimentally determined values of semi-refined
rice oil energy are used in the feed formulation, then semirefined
rice oil can be used as replacement for refined soybean