Published May 15, 2015
Antioxidant activity in plasma and rumen
papillae development in lambs fed fermented apple pomace
C. Rodríguez-Muela,* H. E. Rodríguez,† C. Arzola,*1 D. Díaz-Plascencia,* J. A. Ramírez-Godínez,* A.
Flores-Mariñelarena,* P. F. Mancillas-Flores,* and G. Corral*
*Autonomous University of Chihuahua. Chihuahua, Chihuahua, Mexico 31000; †Ministry
of Agriculture, Animal Production, Rural Development, Fisheries and Food. Chihuahua, Chihuahua, Mexico 31020.
ABSTRACT: The effect of fermented apple pomace
(FAP) on animal health, antioxidant activity (AA),
hematic biometry (HBm) and the development of
ruminal epithelium were investigated in a study with
24 finishing lambs (BW = 25.4 ± 3.3 Kg). Lambs
were grouped by sex (12 male and 12 female) and
fed (n = 6 per group of treatment) a basal fattening
diet (Control diet, T1) or the basal diet supplemented
to include 10.91% of fermented apple pomace (FAP
diet, T2). The animals were kept 56 d in individual
metabolic cages, with ad libitum access to water
and feed. Two blood samples were collected from
each animal on d 0, 28, and 56 to determine AA in
plasma and hematic biometry (HBm). Four samples
of ruminal tissue were taken postmortem to evaluate
the development of ruminal epithelium based on the
length (LP) and width (WP) of papillae. AA and HBm
data were analyzed with a mixed model (fixed effects:
diet, sampling, sex, and their interaction; using the
experimental unit nested in the effect of the diet as
the random effect). LP and WP were analyzed with a
hierarchical model, as simple and nested effects in the
sampling site, where the fixed effects were the diet
and the sex of the animal and their interaction. There
was an effect of diet on AA, which was higher (P <
0.06) in T2 vs. T1 at 56 d (24.34 vs. 21.79 mM Fe2).
Leukocytes increased (P < 0.05) from 7.52*103 ±
1.29*103/μL to 9.14*103 ± 1.24*103/μL1 in all the
animals in the experiment, with a marked increased
(P < 0.05) at 28 d after beginning of the feeding
period, with values within the normal range for this
species and without effect of the diet (P > 0.05) for
the other indicators of HBm. Males’ LP was higher
in T2 than in T1 (P < 0.05). It was concluded that
the use of FAP in the diets of finishing sheep reaped
benefits on animal health and the development of
rumen epithelium by improving antioxidant activity
in plasma and stimulating the growth of papillae.
Key words: antioxidant, fermented apple pomace, lamb, papillae
© 2015 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2015.93:2357–2362
doi:10.2527/jas2014-8670
Introduction
The apple is a fruit with positive effects on human
health attributes due to its phenol content that has antioxidant properties (Alberto et al., 2006). Fermented
apple pomace (FAP) is a feed product that is obtained
from solid-state fermentation (SSF) of apple pomace.
Yeast concentration and nutritive quality of the protein
increase during fermentation of pomace as result of mi1Corresponding
author: [email protected]
Received October 29, 2014.
Accepted February 26, 2015.
crobial growth (Becerra, 2006). It is possible that FAP
conserves the properties of the fruit and positively influences parameters related to animal health. Its yeast and
phenol content can improve fermentation in the rumen
and improve udder health, milk production, and profitability of the herd. The effect of FAP on general health
of the animal can be assessed through the determination
of antioxidant activity (AA) in plasma and the blood cell
count involved in the immunological system. Gallegos
(2007) found that FAP incorporation into lactating cow
diets increased monocytes counts and AA in blood.
As a protein ingredient in ruminant feed, FAP
can partly substitute grain sources of protein and en-
2357
2358
Rodríguez-Muela et al.
ergy that are used in their diets (Rodríguez-Muela et al.,
2010), which can increase productivity and reduce feeding costs. Also, FAP used in sheep diets could result in
changes in the development of internal ruminal mucosa
by partially replacing grains and the changes induced in
the physical-chemical characteristics in fattening diets.
This effect can be evaluated through the size of the rumen papillae (Lesmeister et al., 2004). The objective of
this work was to assess the effect of including FAP in the
diet on the health of male and female sheep by analyzing
AA in blood plasma, hematic biometry in plasma, and
the development of mucosa in the rumen epithelium.
Materials and Methods
This trial was conducted under the guidelines of the
Code of Bioethics and Regulation of Animal Welfare of
The Autonomous University of Chihuahua. A total of
24 lambs were used, with 25.4 ± 3.3 kg BW and 147.0
± 9.5 d old (n = 24, 12 males and 12 females), half of
which were fed a typical diet for fattening sheep (Control diet, T1) and rest with a diet that included 10.91% of
FAP (T2). Animals were Charolais × (Katahdin*Dorper)
crosses as the paternal and maternal breeds, respectively.
Lambs were grouped by sex and subsequently randomly
assigned to 1 of the 2 diets, thus leaving 2 groups of
males (M) and 2 groups of females (F) composed of 6
animals each. Before the study, the animals were separated into 2 groups and fed alfalfa hay plus 300 g/animal
d–1 of commercial concentrate for 30 d. At the beginning
of the experimental diet, the animals were transferred
to metabolic cages (1.20 × 0.6 × 1.10 m, length, width
and depth, respectively). The animals were allowed a 4
h resting period outside of their individual cage each day.
First sampling was taken at the beginning of the evaluation period. Diets were isoproteic and isoenergetic formulated according to the tables of NRC (1985), with an
expected weight gain of 300 g/d. The animals received
food and water ad libitum during the evaluation period.
The FAP diet (T2) included 10.91% of FAP (DM basis)
to feed 6 M and 6 F lambs, while the control diet (T1)
was fed the same diet, excluding FAP and was used to
feed the same number of animals as T2. Table 1 shows
the chemical composition of FAP. The composition of
the diets used is shown in Table 2.
The methodology described by Becerra (2006) was
used to prepare FAP. Solid state fermentation was performed on a concrete surface. At the beginning of the
process, 1.5% of urea, 0.4% of (NH4)2SO4, and 0.5%
of a commercial mineral mix were added to FAP. During the process, the substrate was turned around up to
3 times a day to incorporate oxygen in the fermentation bed from 0 d to 6 d of the SSF period. On d 6, the
fermented substrate was spread on a concrete surface
Table 1. Chemical composition of fermented apple
pomace (mean ± standard error)1,2
Item
DM (%)
Ash (%)
CP (%)
Crude Fiber (%)
NDF (%)
ADF (%)
Crude Fat (%)
TPP3 compounds (mg/g)
Yeast (cfu/g)
1DM
Composition
69.6 ± 3.4
3.2 ± 0.4
21.6 ± 1.7
35.1 ± 1.1
28.6 ± 0.79
24.7 ± 0.52
3.2 ± 1.3
8.0 ± 1.4
3.75*108
basis.
2Composition
3TPP =
after 5 d of solid state fermentation.
total polyphenols.
to dry up in the Sun and was stored. The FAP obtained
was ground in a hammer mill before being mixed with
the other ingredients.
At d 0, 28, and 56 of the feeding period 2 blood samples were taken from each lamb (jugular vein) before
being fed. The samples were collected in 4-mL tubes.
A sample was used to determine AA in plasma and the
other to conduct hematic biometry (HBm). Immediately
after taking the blood samples, the tubes with blood and
anticoagulant were labeled and placed in a container
with ice. To quantify AA, the samples were centrifuged
at 2,700 g during 15 min, the serum was then decanted,
and the tubes with plasma were sealed to conserve the
samples by freezing (–6°C), until analyzed, according to
the procedure developed by Benzie and Strain (1996).
The HBm was performed in the Diagnostic Center
Laboratory of the University Clinic. The quantity of
blood cell components was determined with a Beckman Coulter Ac·T 5diff AL hematology analyzer (Aiello and Mays, 2000).
The evaluation of the rumen samples was based on
the procedure developed by Lesmeister et al. (2004).
These researchers indicated that the development of
the multilayered rumen epithelium is associated with
the diet, and this development is reflected mainly in
the length and width of papillae. These authors indicated the proper locations for sampling, the quantity of
samples to be taken, and the number of observations
that should be taken to carry out these analyses.
For the analysis of the ruminal epithelium, each
sample was taken from a different area of the rumen immediately after slaughtering the animals: the first was
taken from the dorsal caudal region, the second from the
ventral caudal region, the third from the dorsal craneal
region, and the fourth from the ventral craneal region.
The tissue samples where ~4 cm in diameter. The residual ruminal content were eliminated with water and conserved in a solution of phormol at 18% in polyethylene
Rumen papillae development in lambs fed FAP
2359
Table 2. Composition of the diets used1
Diet
Ingredient
Alfalfa
Soya paste
Rolled corn
Fermented apple pomace
Animal fat
Molasses
Salt
Mineral premix
Total
Chemical analysis
Dry matter
Crude protein
Ether extract
Neutral detergent fiber
Acid detergent fiber
Crude fiber
Ash
1Values
T2 (with FAP)
28.72
9.41
43.34
10.91
2.29
3.61
0.76
0.95
100.00
T1 (Control)
38.43
12.44
42.54
0.00
1.98
3.12
0.66
0.82
100.00
91.32
11.43
6.43
23.84
13.17
20.0
7.31
90.59
11.44
5.76
21.45
10.81
15.0
7.23
expressed in percentages AF basis.
containers of ~100 mL and identified when the length
and width of the papillae of the tissue were determined.
After measuring the size of papillae, the samples
were dissected into 3 parts in horizontal cuts taking the
growth of the papillae as a reference. Three papillae
were randomly selected from each cut to measure length
(LP) and width (WP) using a (SURTEK) dial calibrator.
The measurements were registered in millimeters with
a minimum calibrator resolution of 0.01 mm. In total, 9
observations were obtained per sample.
Statistical Analysis
The statistical analysis of AA and HBm variables
(leukocytes, neutrophils, lymphocytes, monocytes, eosinophils, basophils, erythrocytes, and hematocrits) were
conducted using a mixed model. The fixed effects were
diet, the sampling (over time), sex (M or F), and their interactions, while the random effect was the lamb nested
in the treatment. The age in days and the weight of the
animals at the time of sampling were used as covariables.
The results of the variance analysis, means, standard error, and comparison among means were obtained
with PROC MIXED of SAS (SAS Inst. Inc., Cary, NC).
LP and WP were evaluated with a hierarchical
model; diet, the sex of the animal, and their interaction
were used as simple and nested effects per the ruminal
area of the sampling, as indicated by Lesmeister et al.
(2004). The age in days and weight of the animal at
slaughter were used as covariables since these variables influence the development of rumen epithelium
(Heinrichs, 2005).
Figure 1. Antioxidant activity as measured by the ferric reductive
ability of blood plasma of lambs fed on diets with and without fermented
apple pomace (FAP).
The results of the variance analysis, means, standard
error, and comparisons among means were obtained with
the GLM procedure of SAS (SAS Inst. Inc.).
Results and Discussion
There was an effect on AA interaction (P < 0.05) of
the diet with sampling (sampling time). The AA of the
2 diets was similar at the beginning of the evaluation;
however, from the first to the second sampling, there
were observed increments in animals of both tretments
(P > 0.06). In contrast, from the second to the third sampling, it was observed that AA decreased, but to a lesser
degree in the T2 animals than in the T1 (P < 0.06).
Despite the changes described above, the AA level at
the end of the evaluation did not differ from initial AA. It
is important to note that AA was higher in T2 lambs (P <
0.06) than in T1 lambs in the final sampling (Fig. 1).
Gallegos (2007) found that in lactating cows fed
with and without FAP, AA increased with a balanced
diet. There could have been a similar effect in this
work with the free access to their diets that allowed the
animals to meet their nutritional requirements without
any restrictions, which increased AA in plasma.
An organism enters into oxidative stress state when
the antioxidant response of the body is insufficient to
maintain a normal level of reactive oxygen species
(ROS) or simply when ROS levels are higher than the
levels of body antioxidants (Bush et al., 2007; Kataria
and Kataria, 2012); oxidative stress is accentuated in
the presence of illnesses and physiological disorders
(Weiss and Mahan, 2008; Guo et al., 2013). The compounds known as ROS are molecules produced in
the metabolism of the oxygen in the body and there
are some factors of environmental stress or related to
physiological state of the animal that can increase the
2360
Rodríguez-Muela et al.
Table 3. Quantity of leukocytes in the plasma of lambs
of control and fed FAP1
Sex
Males
Females
Average
T2 (FAP diet)
7.65 ± 0.62ab
8.21 ± 0.62ab
7.93 ± 0.37
T1 (Control diet)
9.29 ± 0.54a
6.88 ± 0.54b
8.09 ± 0.37
Average ± SE
8.47 ± 0.43
7.55 ± 0.43
1103
µL–1; FAP = fermented apple pomace.
letters in the same column indicate differences (P < 0.05)
for the effect of the diet-sex interaction.
a,bDifferent
production of these compounds and harm plasmatic
membranes, proteins, and DNA (Hansen, 2008).
The antioxidant response in the body is favored by
the presence of vitamins (principally E), selenium, and
antioxidant enzymes (Karataş et al., 2006), but can also
be stimulated by some polyphenols in foods (Ndhlala et
al., 2006; Dominguez-Perles et al., 2014). The evaluation of AA in a general manner reflects the antioxidant
state of the body (Gallegos, 2007), independent of the
mechanism of action of the antioxidant compounds.
In this work, the diet with FAP (T2) resulted in the
lambs having a higher AA level by the end of the evaluation period compared to the T1 lambs, which indicates that
they might have a higher resistance to metabolic damage
caused by the presence of ROS or oxidative stress.
The results of the Hematic biometry showed normal values among all with the treatments, except in
the case of the quantity of leukocytes in the plasma.
The quantity of leukocytes in T1 males was higher
(P < 0.05) than the females fed on the same diet. The
quantity of leukocytes in the T2 animals was similar
(P > 0.05) to that of the T1 (Table 3).
The quantity of leukocytes in the blood increased
(P < 0.05) from the second to third sampling in all the
animals (Fig. 2). The average quantity of leukocyte cells
was 7.52 *103 ± 1.29*103/μL at the beginning of the
evaluation, 7.36*103 ± 0.34*103/μL in the second sampling, and 9.14*103 ± 1.24*103/μL in the third sampling.
The parameters obtained in this work are within
the normal range for young sheep (4 to 12*103/μL;
Aiello and Mays, 2000). This variable reflects the total
of white blood cells; a differential leukocyte count allows for calculating the proportions and the changes
among the different types of leukocytes.
The white blood cell profile (leukogram or differential analysis of leukocytes) is influenced by sex, age,
nutrition, physical exercise, and diurnal and sexual cycles of the animals; in some cases, the number of leukocytes increases with acute bacterial infections, leukemia, cystic necrosis, and chemical or metabolic poisoning. However, these situations can also generate high
levels of leukocytes (Aiello and Mays, 2000). No sick
animals were observed during the experimental period
in this trial, and weight gains were in the normal range.
Figure 2. Quantity of leukocytes in the blood of lambs with and
without fermented apple pomace (FAP) in the diet.
Regarding the development of ruminal epithelium,
LP showed an effect (P < 0.05) in the interaction of diet
and the sex of the animal, depending on the area of the tissue sample (nested effect). There was also an effect (P <
0.05) of this interaction independently of the area of the
rumen from where the sample was taken (non-nested effect). There was an effect of the age (P < 0.05) and weight
(P < 0.07) of the animal (covariables) on LP (Table 4).
LP was higher (P < 0.05) in the dorsal caudal region of the rumen in T2 males than in the other groups
of animals. The T2 females had higher LP (P < 0.05)
than the T1 males. The T2 females had lower LP (P <
0.05) in the ventral caudal region than did the T1 males.
No differences were observed (P > 0.05) in the
craneal dorsal region of the rumen. LP in the ventral
craneal region was different for each group (P < 0.05);
being highest (P < 0.05) among T2 males, followed by
T2 females, and then T1 females, with T1 males having the lowest LP (P < 0.05).
In general (non-nested effect of diet and sex),
the T2 males had the highest LP (P < 0.05), while T1
males had the lowest (P < 0.05) LP. There were no
differences between T2 and T1 females (P > 0.05).
Higher LP can be attributed to higher VFA production,
given that VFA production influences the development
of papillae (Flatt et al., 1958; Heinrichs, 2005; Khan et
al., 2007), provided there are no problems of acidity in
the rumen (Suárez et al., 2007).
For the variable papillae width (WP), there was an
effect (P < 0.05) in the interaction of diet by the sex of
the animal, depending on the area of the rumen from
which the sample was taken (nested effect). An effect
(P < 0.05) was also observed of diet on this variable,
independently of the area of the rumen where the sample was taken (non-nested effect). There was an influence of the age (P < 0.05) and the weight (P < 0.05) of
the animal (covariables) on WP in the development of
multilayered rumen epithelium (Table 5).
Rumen papillae development in lambs fed FAP
Table 4. Length of ruminal papillae1
Variable
T2 (Diet with FAP) T1 (Control diet)
Area 1 (Dorsal caudal region)
Males
3.56 ± 0.11a
2.60 ± 0.11b
c
Females
3.13 ± 0.11
3.13 ± 0.11c
Average
3.35 ± 0.07
2.87 ± 0.07
Area 2 (Ventral caudal part)
Males
2.10 ± 0.11ab
2.18 ± 0.11b
a
Females
1.84 ± 0.11
2.06 ± 0.11ab
Average
1.97 ± 0.07
2.12 ± 0.07
Area 3 (Dorsal cranial part)
Males
2.22 ± 0.11
2.14 ± 0.11
Females
1.93 ± 0.11
2.15 ± 0.12
Average
2.07 ± 0.07
2.14 ± 0.08
Area 4 (Ventral cranial part)
Males
4.27 ± 0.11a
2.81 ± 011b
c
Females
3.67 ± 0.11
3.36 ± 0.11d
Average
3.97 ± 0.07
3.08 ± 0.07
Non-nested effect of the diet-sex interaction
2.43 ± 0.05b
Males
3.04 ± 0.07a
c
Females
2.64 ± 0.06
2.67 ± 0.06c
Average
2.84 ± 0.04
2.55 ± 0.04
2361
Table 5. Width of ruminal Papillae1
Average ± EE
2.73 ± 0.05
2.65 ± 0.05
2.14 ± 0.08
1.95 ± 0.08
2.18 ± 0.08
2.04 ± 0.08
3.51 ± 0.08
3.54 ± 0.08
2.73 ± 0.05
2.66 ± 0.05
Variable
T2 (Diet FAP)
T1 (Control diet)
Area 1 (Dorsal caudal part)
Males
2.15 ± 0.05a
1.80 ± 0.05b
ac
Females
2.02 ± 0.05
1.98 ± 0.05c
Average
2.09 ± 0.04
1.89 ± 0.04
Area 2 (Ventral caudal part)
Males
1.82 ± 0.05
1.81 ± 0.05
Females
1.79 ± 0.05
1.78 ± 0.05
Average
1.80 ± 0.04
1.80 ± 0.04
Area 3 (Dorsal craneal part)
Males
1.87 ± 0.05
1.93 ± 0.05
Females
1.80 ± 0.05
1.84 ± 0.06
Average
1.84 ± 0.04
1.88 ± 0.04
Area 4 (Ventral craneal part)
Males
2.10 ± 0.05a
2.00 ± 0.05a
b
Females
2.34 ± 0.05
2.07 ± 0.05a
Average
2.22 ± 0.04
2.03 ± 0.04
Non-nested effect of the diet-sex interaction
Males
1.98 ± 0.03
1.89 ± 0.03
Females
1.99 ± 0.03
1.91 ± 0.03
1.90 ± 0.02b
Average
1.99 ± 0.02a
Average
1.98 ± 0.04
2.00 ± 0.05
1.81 ± 0.04
1.79 ± 0.04
1.90 ± 0.04
1.82 ± 0.04
2.05 ± 0.04
2.21 ± 0.04
1.93 ± 0.02
1.95 ± 0.02
1mm.
1mm.
a–dDifferent
a–cDifferent letters in the same columns indicate differences (P < 0.05).
letters in a column indicate differences (P < 0.05).
WP was higher (P < 0.05) in the dorsal caudal part
of the rumen of T2 males than in T1 males; the T2
females had higher WP (P < 0.05) than the T1 males,
but not higher (P > 0.05) than that of the T1 females.
No differences (P > 0.05) were found among the
animals in the ventral caudal and dorsal craneal regions of the rumen. However, WP was higher (P <
0.05) in the ventral craneal region of the rumen of T2
females than in the other groups of lambs.
In general, it could be observed that the WP in
the multilayered rumen epithelium in the lambs fed
with FAP was higher (P < 0.05) than in that of the
lambs fed with the diet without FAP. Similarly to what
happened with the LP, higher WP can be attributed
to higher VFA production, given that WP production
influences the development of papillae (Flatt et al.,
1958; Heinrichs, 2005; Khan et al., 2007), provided
there are no problems of ruminal acidity (Suárez et al.,
2007). The effect in this work was notable in the dorsal caudal region of the rumen, where the products of
ruminal fermentation are observed, and in the ventral
craneal part of the rumen, which is the part close to the
omasum and abomasum and where the abrasiveness
of the diet can have an effect by removing dead cells.
The results of antioxidant activity and hematic
biometry show a response until 56d of feeding with
the FAP diet and as the lambs had reached an age that
could be classified as adult or at the initial stage of maturity, it is recommendable to undertake studies with
a longer feeding period, a greater number of young
lambs and characterize the quantity of vitamins A, B,
C, D, and E in FAP and its phenolic content of FAP,
as well as determining with tests with animals which
components of FAP increase antioxidant activity or
determine if the antioxidant activity is due to the influence of the type of diet or to an ingredient on the enzymatic axis that maintains the metabolic redox balance.
Conclusions
The use of FAP in the diet favors the health of the
finishing lambs given that higher levels of antioxidant
activity were registered in plasma after feeding them
with a FAP diet for a period of at least 30 d ad libitum.
Lambs fed diets supplemented with FAP for at least 28
d had higher leukocyte counts in blood and increased
antioxidant activity and the response of the immunological system, independent of the sex of the animal
used. The FAP diet stimulated the growth of multilayered rumen epithelium, increased the dimensions of the
papillae, and resulted in a healthier rumen in the finishing lambs. In general, the inclusion of FAP in diets of
finishing lambs improved their general state of health.
Literature Cited
Aiello, S. E., and A. Mays (Eds). 2000. The Merck veterinary manual. 5th ed. Océano Grupo Editorial, Barcelona, Spain.
Alberto, M. R., M. A. R. Canavosio, and M. C. Manca de Nadra.
2006. Antimicrobial effect of polyphenols from apple skins on
human bacterial pathogens. Electron. J. Biotechnol. 9:205–209.
2362
Rodríguez-Muela et al.
Becerra, B. A. 2006. Apple byproduct utilization using microbial protein production with solid state fermentation in animal nutrition.
PhD Diss: Autonomous Univ. of Chihuahua, Chihuahua, México.
Benzie, I. F. F., and J. J. Strain. 1996. Ferric reductive ability
of plasma (FRAP) as a measure of antioxidant power: The
FRAP assay. Anal. Biochem. 239:70–76.
Bush, S., K. Gyenai, X. Guan, and T. Geng. 2007. Oxidative stress
and immune response in the chicken. J. Anim. Sci. 85(Suppl.
1):52. (Abstr.)
Dominguez-Perles, R, A. I. Teixeira, E. Rosa, and A. I. Barros. 2014.
Assessment of (poly)phenols in grape (Vitis vinifera L.) stems
by using food/pharma industry compatible solvents and Response Surface Methodology. Food Chem. 164:339–346.
Flatt, W. P., R. G. Warner, and J. K. Loosli. 1958. Influence of purified materials on the development of the ruminant Stomach. J.
Dairy Sci. 41:1593–1600.
Gallegos, M. A. 2007. Somatic cell count in milk, antioxidant activity of cellular blood components and plasma of lactating
Holstein cows fed with manzarina in the diet. M.C. Thesis.
Autonomous University of Chihuahua. Chihuahua, México.
Guo, Y., X. Xu, Y. Zou, Z. Yang, S. Li, and Z. Cao. 2013. Changes
in feed intake, nutrient digestion, plasma metabolites, and oxidative stress parameters in dairy cows with subacute ruminal
acidosis and its regulation with pelleted beet pulp. J. Anim.
Sci. Biotechnol. 4:31.
Hansen, P. J. 2008. Effectiveness of supplemental antioxidants for
enhancing reproductive function in cattle. J. Dairy Sci. 86(ESuppl. 2):321. (Abstr.)
Heinrichs, J. 2005. Rumen development in the dairy calf. Adv.
Dairy Technol. 17:179–187.
Karataş, F., I. Halifeoğlu, M. Karatepe, V. Konar, H. Canatan, and
R. Çolak. 2006. Evaluation of changes in levels of serum selenium, MDA and antioxidant vitamins (A, E, C) in diabetic
patients. Firat Üniv. Sağlik Bilimleri Dergisi. 20(6):391–395.
Kataria, A. K., and N. Kataria. 2012. Evaluation of oxidative stress
in sheep affected with peste des petits ruminants. J. Stress
Physiol. Biochem. 8:72–77.
Khan, M. A., H. J. Lee, W. S. Lee, H. S. Kim, K. S. Ki, T. Y. Hur,
G. H. Suh, S. J. Kang, and Y. J. Choi. 2007. Structural growth,
rumen development, and metabolic and immune responses of
holstein male calves fed milk through step-down and conventional methods. J. Dairy Sci. 90:3376–3387.
Lesmeister, K. E., P. R. Tozer, and A. J. Heinrichs. 2004. Development and analysis of a rumen tissue sampling procedure. J.
Dairy Sci. 87:1336–1344.
Ndhlala, A. R., C. H. Mupure, K. Chitindingu, M. A. N. Benhura,
and M. Muchuweti. 2006. Antioxidant potentials and degrees
of polymerization of six wild fruits. Sci. Res. Essay. 1:87–92.
NRC. 1985. Nutrient requirements of sheep. 5th rev. ed. Natl.
Acad. Press, Washington, DC.
Rodríguez-Muela C., H. E. Rodríguez-Ramírez, A. Grado, A. Corral, O.
Ruiz-Barrera, C. Arzola, and R. Bocourt. 2010. Effect of the fermented apple pomace (manzarina) on the rumen epithelia growth
with lamb feedlot diets. J. Anim. Sci. 88(E-Suppl. 2):618 (Abstr.)
Suárez, B. J., C. G. Van Reenen, N. Stockhofe, J. Dijkstra, and W.
J. J. Gerrits. 2007. Effect of roughage source and roughage to
concentrate ratio on animal performance and rumen development in veal calves. J. Dairy Sci. 90:2390–2403.
Weiss, W. P., and D. C. Mahan. 2008. Oxidative stress during the
life cycle of animals. J. Dairy Sci. 86(E-Suppl. 2):383. (Abstr.)