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Vitamin E Supplementation and its Effects on Broiler Performance,
Nutrient Absorption and Health Markers
Onaolapo A.A.
1*
, Seidu S.
2
, Bashir S. A
1
, Olatunde A.O.
1
1
Department of Agricultural Technology, Federal Polytechnic Ayede, Nigeria
2
Global Food System Quality and Sustainability, Sheffield Business School, Sheffield Hallam University,
UK.
*
Corresponding Author
DOI: https://dx.doi.org/10.51244/IJRSI.2025.1210000193
Received: 22 October 2025; Accepted: 28 October 2025; Published: 15 November 2025
ABSTRACT
Vitamin E plays a critical role in antioxidant defense and immune function in poultry, yet optimal dietary
inclusion levels remain poorly defined. This study investigated the dose-dependent effects of dietary vitamin E
supplementation on growth performance, nutrient digestibility, and hematological indices in broiler chickens.
Ninety-six day-old Marshall broiler chicks were distributed across four dietary treatments with graded vitamin
E levels (n = 24 per treatment). Weight gain increased with increasing vitamin E supplementation, resulting in
improved feed conversion ratio. Crude protein digestibility showed a positive dose-dependent response
(p<0.001), while ether extract digestibility decreased with increasing vitamin E supplementation. Hematological
parameters demonstrated variable responses to vitamin E levels. Serum biochemistry remained largely
unaffected, except for low-density lipoprotein which showed a negative dose-dependent relationship. These
findings indicate beneficial effects of vitamin E supplementation on growth performance and protein utilization
in broilers. From a practical standpoint, the improved feed conversion ratio and enhanced protein digestibility
associated with vitamin E supplementation offer favorable economic returns for commercial broiler production,
making it a cost-effective nutritional strategy for poultry farmers.
INTRODUCTION
Protein malnutrition remains a persistent global health challenge, affecting over 820 million people worldwide
and disproportionately impacting populations in low- and middle-income countries (UNICEF, 2023).
Animalsource foods, particularly poultry products, represent strategically important interventions for addressing
concurrent macronutrient and micronutrient deficiencies while promoting sustainable food production systems.
Poultry production has emerged as one of the fastest-growing food production sectors globally, with broiler meat
production exceeding 137 million tonnes annually (Bist et al., 2024). This growth reflects several intrinsic
advantages: superior feed conversion efficiency (1.7-2.0 kg feed per kg meat gain), rapid production cycles, and
exceptional scalability across diverse production environments (Costa, 2009; Mottet & Tempio, 2017). Broiler
chickens achieve market weight within six to eight weeks, facilitating rapid capital turnover (Mramba &
Mapunda, 2024). Poultry meat exhibits favorable nutritional characteristics including high protein content
(2022%), low intramuscular fat, and excellent digestibility (>95% for essential amino acids), making it suitable
for diverse dietary requirements (Ajayi, 2010; Bordoni & Danesi, 2017).
Despite its strategic importance, commercial poultry production faces mounting challenges. Feed costs constitute
60-70% of total production expenses, exacerbated by volatile input markets and climate variability (Mengesha
et al., 2008). These pressures necessitate integrated strategies for optimizing production efficiency and enhancing
flock health resilience through nutritionally optimized diets that precisely meet the complex requirements of
modern broiler genotypes.
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Oxidative stress, characterized by an imbalance between reactive oxygen species (ROS) production and
endogenous antioxidant capacity (Juan et al., 2021), has been identified as a fundamental physiological constraint
on broiler productivity and health (Xiao et al., 2011). Under conditions of thermal stress, high stocking densities,
or accelerated growth, broilers experience elevated metabolic rates and increased ROS generation, resulting in
systemic oxidative damage to cellular lipids, proteins, and nucleic acids (Adebiyi, 2011). This oxidative insult
manifests as reduced growth performance, impaired nutrient utilization, immune suppression, and compromised
meat quality attributes including colour stability and shelf-life (Rahman, 2007; Simitzis et al., 2012).
Consequently, exogenous antioxidant supplementation has become standard practice in commercial poultry
nutrition.
Vitamin E comprises eight naturally occurring compounds, four tocopherols (α-, β-, γ-, δ-tocopherol) and four
tocotrienols, collectively functioning as lipophilic antioxidants and cell signaling molecules (Szewczyk et al.,
2021). α-Tocopherol, the most biologically active isoform in avian species, preferentially accumulates in cellular
membranes where it neutralizes lipid peroxyl radicals and interrupts lipid peroxidation (Gao et al., 2010; Pompeu
et al., 2018). Beyond antioxidant functions, vitamin E modulates nuclear factor-kappa B (NF-κB) signalling,
enhances immune cell activation, amplifies antibody responses, and supports optimal physiological performance
during critical developmental and stress periods (Selim et al., 2013). At the production level, adequate vitamin
E status enhances lipid stability in meat products, extends shelf-life, and potentially increases economic returns
through improved feed conversion efficiency (Buckley & Morrissey, 1992; Kennedy et al., 1992).
While the general importance of vitamin E in poultry nutrition is well-established, critical knowledge gaps persist
regarding optimal dietary inclusion levels, dose-response relationships under varied environmental and genetic
contexts, and potential interactions with other micronutrients. The dose-dependent effects of dietary vitamin E
supplementation on broiler growth performance, apparent nutrient digestibility, hematological health markers,
and serum biochemical profiles remain incompletely characterized, particularly within tropical and subtropical
production environments characterized by chronically elevated ambient temperatures and corresponding
metabolic stressors. Furthermore, the relative cost-effectiveness of varying supplementation strategies and the
long-term health implications of different micronutrient fortification approaches warrant systematic
investigation to support evidence-based recommendations for commercial poultry producers.
Research Objective
This study was designed to elucidate the dose-dependent effects of dietary vitamin E supplementation on growth
performance, apparent nutrient digestibility, hematological parameters, and serum biochemical profiles in broiler
chickens under standardized production conditions. The overarching objective was to establish evidence-based
recommendations for optimal vitamin E fortification strategies in commercial poultry diets, particularly for
tropical and subtropical production environments where oxidative stress challenges are pronounced. This
research addresses critical knowledge gaps in vitamin E dose-response relationships and contributes to enhanced
productivity, product quality, and flock health resilience in modern poultry production systems.
MATERIALS AND METHODS
Experimental Design and Housing
A Completely Randomized Design (CRD) with four dietary treatments and three replications per treatment was
employed. Ninety-six unsexed, day-old Marshall broiler chicks (Gallus domesticus) were obtained from a
commercial hatchery (Obasanjo Farms, Nigeria) and housed in twelve pens (3.0 m × 2.5 m each) with eight birds
per replicate, providing a stocking density of approximately 10.7 birds per square meter. Wood shavings were
used as bedding material and replaced weekly. Artificial heating was provided during brooding (weeks 1-2) using
100-watt incandescent bulbs to maintain pen temperatures at 32-34°C, with gradual temperature reduction in
subsequent weeks. Natural ventilation was maintained throughout the trial.
Experimental Diets and Feeding Management
All birds received a common basal diet during a one-week brooding phase prior to treatment allocation. Four
isocaloric and isonitrogenous experimental diets were formulated to meet NRC requirements with varying levels
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of vitamin E (α-tocopheryl acetate; Evonik Industries AG, Essen, Germany) supplementation: Treatment 1 (0.5
g/kg), Treatment 2 (1.0 g/kg), Treatment 3 (1.5 g/kg), and (Control, 0 g/kg additional vitamin E). Experimental
diets were provided from week two throughout the eight-week trial. Birds were fed ad libitum using linear
feeders, with fresh water provided continuously via bell drinkers.
Table 1. Composition of basal feed and feeding time line into plain tubes for serum collection.
Hematological parameters assessed included packed cell volume (PCV; %), hemoglobin concentration (Hb;
g/dL), red blood cell count (RBC; × 10⁶/μL), and white blood cell count (WBC; × 10³/μL), determined using an
automated hematology analyzer (Sysmex KX-21, Kobe, Japan). Serum samples were obtained by centrifugation
at 3,000 × g for 10 minutes and stored at −20°C pending analysis. Serum biochemical parameters analyzed
included total protein (TP; g/dL), glucose (mg/dL), total cholesterol (TC; mg/dL), high-density lipoprotein
cholesterol (HDL-C; mg/dL), and low-density lipoprotein cholesterol (LDL-C; mg/dL), determined using a
semiautomated clinical chemistry analyzer (Cormay Liasys, Piaseczno, Poland).
Statistical Analysis
All data were subjected to one-way analysis of variance (ANOVA) using the General Linear Model procedure.
Treatment means were compared using Duncan's Multiple Range Test (DMRT) at P < 0.05. Homogeneity of
variance was verified using Levene's test, and normality of residuals was assessed through Shapiro-Wilk testing.
Statistical analyses were conducted using SPSS software (version 25.0; IBM Corporation, Armonk, NY, USA).
Results are presented as treatment means with standard deviation (SD).
Ingredients
Starter 0-
4 Weeks
Finisher 4-
8 Weeks
Maize (kg) 60 64
Fish Meal (kg) 2 0.3
Soya Bean Meal (kg)
23 19
GNC (kg) 8 7
Wheat bran (kg) 2 4
Bone meal (kg) 2.5 3
Oyster shell (kg) 1.5 1.5
Methionine (kg) 0.2 0.15
L-lysine (kg) 0.2 0.15
Micro mic broiler (kg)
0.3 0.3
Salt (kg) 0.3 0.3
Atox (kg) 0.3 0.3
ME (Kcal) 2793 3001
CP % 21.00 18.90
Fat % 2.10 4.50
Fibre % 3.00 3.25
Ca % 1.05 1.36
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RESULTS AND DISCUSSIONS
Nutrient Digestibility
Fig. 1. Shows the means of nutrient digestibility of Dry matter (A), Crude protein (B) and Ether extract (C).
Histograms with different annotation are significantly different (p<0.05).
Mean dry matter digestibility values ranged from 55% to 59% across treatments, indicating that vitamin E
supplementation does not substantially impair overall dry matter digestibility in broiler chickens. The
maintenance of dry matter digestibility across treatment groups suggests that the basal diet was formulated to
support adequate nutrient availability regardless of vitamin E status.
Crude protein digestibility (CPD) demonstrated a significant positive dose-dependent relationship with dietary
vitamin E supplementation (Fig. 1; P < 0.001). Birds receiving the control diet exhibited the lowest CPD
(56.38%), with progressive increases at higher vitamin E levels, reaching the highest value in Treatment 3
(65.84%). This response suggests that vitamin E enhances intestinal proteolytic enzyme activity, amino acid
transporter expression, or intestinal epithelial integrity, facilitating improved protein utilization. Vitamin E's role
as a lipophilic antioxidant may stabilize the intestinal epithelium, enhance tight junction integrity, and promote
beneficial microbiota populations that optimize protein fermentation and amino acid bioavailability (Reboul,
2017, 2018). Previous research by Selim et al. (2013) demonstrated that physiological vitamin E concentrations
can positively influence intestinal permeability and tight junction protein expression, potentially enhancing
selective amino acid transport. These findings indicate that adequate vitamin E status is essential for maximizing
crude protein utilization efficiency in broiler production systems.
Ether extract digestibility (EED) showed an inverse trend with increasing vitamin E supplementation. Numerical
values ranged from 53.43% in Treatment 3 (1.5 g/kg vitamin E) to 56.92% in the control diet. The inverse trend
may reflect vitamin E's antioxidant activity altering lipid substrate properties and reducing enzymatic
accessibility for pancreatic lipase-mediated hydrolysis. As documented by Loliger (1991), vitamin E functions
as a lipophilic antioxidant by intercalating into cellular and lipoprotein membranes, where it effectively
scavenges lipid peroxyl radicals. This antioxidant activity, while generally beneficial for preserving lipid
nutritional quality, may inadvertently alter the structural and chemical properties of dietary lipids. Enhanced
protection against lipid oxidation may modify the hydrophobic surface characteristics of lipid droplets and
micelle formation, potentially reducing substrate availability for pancreatic lipase and colipase-mediated
hydrolysis (Traber, 2013). Alternatively, suppression of reactive oxygen species signaling, which regulates
intestinal tight junction permeability and lipid transport processes, may contribute to this pattern (Ebhohimen et
al., 2021; Traber, 2013). These mechanistic insights underscore the complexity of micronutrient interactions in
avian digestive physiology and suggest that vitamin E supplementation strategies should consider potential
tradeoffs between antioxidant protection and lipid digestive efficiency.
These nutrient-specific responses reveal potential trade-offs in vitamin E supplementation. Enhanced protein
digestibility likely reflects improved intestinal epithelial integrity and amino acid transporter function, while the
numerical decline in fat digestibility may result from altered lipid substrate properties. Rather than simply
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providing greater antioxidant protection, elevated vitamin E supplementation may impose subtle costs on lipid
digestive processes. These findings indicate that optimization of vitamin E supplementation must account for
macronutrient-specific effects and align with dietary composition and production objectives. Future
investigations employing stable isotope tracer studies, intestinal tissue sampling, microbiota profiling, and
targeted mechanistic analyses would advance understanding of these divergent digestibility responses and enable
more precise optimization of vitamin E supplementation strategies in broiler production systems.
Performance Characteristics
Body weight gain demonstrated a numerical dose-dependent trend with increasing vitamin E supplementation
(Fig. 2), with the lowest weight gain (653.36 g) observed in control birds and the highest (712.60 g) in birds
receiving 1.5 g/kg vitamin E, representing approximately a 9% increase.
Feed intake differed significantly among treatments (P < 0.001). Birds receiving treatments 1 and 2, exhibited
feed intake values of 15.30 kg, 15.33 kg, respectively, while treatment 3 and control both exhibited 15.34 kg and
differ significantly from other treatments having demonstrated the highest feed intake.
Feed conversion ratios improved with vitamin E supplementation. Treatment 1 (0.5 g/kg vitamin E) exhibited an
FCR of 0.0237 g/kg, while treatments 2 and 3 demonstrated numerically improved ratios of 0.0217 g/kg and
0.0216 g/kg, respectively. Control birds had an FCR of 0.0235 g/kg.
Fig. 2. Shows the broiler performance characteristics with body weight (A) Feed Conversion Ratio
(FCR) (B) and Feed intake (C). Histograms with different annotation are significantly different (p<0.05).
The numerical dose-dependent improvements in body weight gain and feed conversion ratio align with the
enhanced crude protein digestibility observed at higher vitamin E levels. Although growth parameters did not
achieve statistical significance, the consistent numerical trends demonstrate potential practical relevance. This
finding is consistent with Adebiyi (2011) and Sadiq et al. (2023), who reported no significant differences in final
weight and weight gain but observed dose-dependent increases, particularly between control and high
supplementation groups. Similarly, Asghar et al. (1991) found that high vitamin E dosages (100-200 mg/kg)
significantly improved daily weight gain and feed conversion ratio in pigs. However, the present results is in,
contrast with Dalia et al. (2018) and Swain et al. (2000), who reported significant enhancements. These divergent
findings across studies underscore the influence of experimental conditions, dietary composition, and
supplementation levels on vitamin E efficacy.
The improved crude protein digestibility at higher vitamin E levels, coupled with numerically improved feed
conversion ratios, suggests that benefits to amino acid absorption outweigh the numerical reductions in fat
digestibility. The enhanced protein digestibility may also support immune function and other physiological
processes beyond growth (Coetzee & Hoffman, 2001; Guo et al., 2001).
From a cost-benefit perspective, the lack of significant difference in feed intake between treatment 3 and control
is particularly noteworthy. Birds receiving the highest vitamin E supplementation consumed essentially the same
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quantity of feed as control birds yet achieved approximately 9% higher weight gain and 8% improvement in
FCR, translating to superior feed conversion efficiency. In commercial broiler production where feed costs
constitute 60-70% of total expenses, this improved nutrient utilization without increased feed consumption
represents a favorable economic proposition. The cost of vitamin E supplementation is minimal compared to the
value generated from improved weight gain using the same feed input. This economic advantage becomes
magnified at commercial scale, where marginal improvements in feed efficiency translate to substantial cost
savings per kilogram of meat produced.
Serum Biochemistry
Total protein concentrations exhibited a dose-dependent increase with increasing vitamin E supplementation,
ranging from 3.13 g/dL in control birds to 3.63 g/dL in treatment 3. This finding is consistent with Adebiyi
(2011). Triglyceride concentrations also increased with increasing vitamin E supplementation while total
cholesterol exhibited considerable variability.
Low-density lipoprotein (LDL) concentrations demonstrated significant treatment effects (P < 0.001), with
treatments 3 and control exhibiting significantly different values compared to treatments 1 and 2. High-density
lipoprotein (HDL) and very low-density lipoprotein (VLDL) concentrations remains variable across all
treatments. Serum glucose concentrations remained consistent across all treatments.
Table 2. Illustrates the effect of vitamin E on serum characteristics. Means with different superscripts are
significantly different (p>0.05)
(Control)
T1 (0.5g/kg)
T2 (1.0g/kg)
T3 (1.5g/kg)
48.28
53.45
49.43
33.80
216.67
197.00
208.00
186.00
3.13
3.59
3.33
3.63
112.42
105.56
109.57
113.07
118.3
109.38
97.03
109.82
9.79
b
11.17
a
10.4
a
6.34
ab
6.65
10.69
9.87
6.76
DISCUSSION
The numerical increase in total protein concentrations with increasing vitamin E supplementation aligns with the
enhanced crude protein digestibility observed in this study. This relationship suggests that improved intestinal
amino acid absorption translates to increased circulating protein availability. The approximately 16% increase
from control to the highest supplementation level indicates potential biological relevance for protein utilization
and tissue accretion, though larger sample sizes are needed to confirm statistical significance.
The reduction in triglyceride concentrations with increasing vitamin E supplementation represents a favorable
metabolic outcome, suggesting enhanced lipid utilization or reduced hepatic lipogenesis. Vitamin E's antioxidant
properties may protect circulating lipoproteins from oxidative modification, facilitating more efficient lipid
metabolism (Pompeu et al., 2018).
The significant differences in LDL cholesterol concentrations across treatments align with findings of Bolukbasi
et al. (2006), who reported similar vitamin E-mediated effects on LDL metabolism in poultry. The specific
pattern, with treatments 3 and 4 differing significantly from treatments 1 and 2, suggests a complex, non-linear
relationship involving vitamin E's antioxidant protection of LDL particles from oxidative modification (Gao et
al., 2010) versus enhanced hepatic LDL receptor expression and clearance (Singh et al., 2014). The lack of
significant differences in HDL and VLDL suggests vitamin E primarily influences LDL metabolism. The absence
of significant effects on serum glucose indicates that vitamin E supplementation does not materially alter
carbohydrate metabolism or insulin sensitivity. This stability in glucose homeostasis, coupled with reduced
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triglycerides and modulated LDL concentrations, suggests that vitamin E supplementation at 1.0-1.5 g/kg
supports favorable metabolic profiles without inducing adverse metabolic perturbations.
These serum biochemical findings complement the nutrient digestibility and performance data, indicating that
vitamin E supplementation influences protein metabolism favourably while modulating lipid metabolism in ways
that may reduce metabolic disease risk. These metabolic effects likely contribute to the observed improvements
in feed conversion efficiency and growth performance.
Haematology
Haemoglobin concentrations exhibited a numerical dose-dependent decrease with increasing vitamin E
supplementation levels. Red blood cell (RBC) counts, white blood cell (WBC) counts, and platelet s remained
relatively consistent across all treatments.
Packed cell volume (PCV) demonstrated significant differences across treatments (P < 0.001). Among
differential white blood cell counts, lymphocyte, heterophil, and monocyte percentages all exhibited statistical
variation across treatments, while eosinophil counts remained relatively stable.
Table 3. shows the effect of vitamin E on haematological parameters. Means with different superscripts are
significantly different (p>0.05)
Treatments
(Control)
T1 (0.5g/kg)
T2 (1.0g/kg)
T3 (1.5g/kg)
PCV
19.00
b
28.25
a
26.33
ab
24.50
ab
Haemoglobin
6.05
9.23
8.40
8.15
Red Blood Cell
1.88
3.18
2.39
2.92
White Blood Cell
12600
17550
16125
19137
Platelet
160.5
189.5
155.5
163.25
Lymphocyte
49.50
b
68.00
a
70.33
a
61.00
ab
Heterophil
44.50
a
26.00
b
24.33
b
30.75
ab
Monocyte
3.50
a
2.00
b
1.67
a
3.50
a
Eosinophil
2.50
3.50
3.67
4.50
DISCUSSION
The dose-dependent decrease in haemoglobin concentrations aligns with findings by Biu et al. (2009) and Akbari
et al. (2008), who observed that higher dietary vitamin E levels reduced haemoglobin concentrations in broilers.
This may reflect vitamin E's antioxidant effects on iron metabolism and haemoglobin turnover, as elevated
vitamin E may reduce oxidative stress-induced erythropoiesis stimulation (Niki, 2015). The maintained RBC
counts despite reduced haemoglobin suggest that vitamin E influences haemoglobin content per erythrocyte
rather than erythrocyte production itself.
The significant differences in packed cell volume (PCV) contrast with Akbari et al. (2008), who reported no
vitamin E effects on PCV. The significant PCV differences observed, coupled with non-significant RBC count
variations, suggest that vitamin E supplementation may modulate erythrocyte size or hydration status through its
influence on erythrocyte membrane fluidity and integrity (Stephen et al., 2017).
The significant differences in lymphocyte, heterophil, and monocyte percentages indicate that vitamin E
supplementation exerts immunomodulatory effects on circulating leukocyte populations. These findings contrast
with Akbari et al. (2008), who reported no significant vitamin E effects on these parameters. The observed
alterations suggest that vitamin E influences immune cell distribution, trafficking, or proliferation. Vitamin E
regulates T-cell proliferation, cytokine production, and immune cell membrane composition (Lee & Han, 2018).
The significant alterations in lymphocyte and monocyte percentages may indicate enhanced immune surveillance
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and adaptive immune capacity, potentially contributing to improved disease resistance. The heterophil changes
may reflect modulation of innate immune responsiveness.
The absence of significant differences in eosinophil counts aligns with Akbari et al. (2008) and suggests that
vitamin E supplementation does not materially affect eosinophil-mediated immune responses. This selective
effect underscores the complexity of vitamin E's immunomodulatory mechanisms.
These haematological findings indicate that vitamin E supplementation influences both erythrocyte
characteristics and immune cell distribution without causing adverse haematological effects. The maintained
RBC, WBC, and platelet counts within normal ranges indicate safe supplementation levels. The
immunomodulatory effects on differential white blood cell populations may contribute to the observed
improvements in nutrient utilization and growth performance, as optimal immune function supports efficient
resource allocation toward productive processes.
CONCLUSION
This study demonstrates that dietary vitamin E supplementation exerts multifaceted, nutrient-specific effects on
broiler chicken physiology. Crude protein digestibility showed a significant positive dose-dependent response,
reaching optimal values at 1.5 g/kg vitamin E inclusion, while ether extract digestibility exhibited a numerical
inverse relationship at higher supplementation levels. These opposing responses underscore that optimization
must account for trade-offs in macronutrient utilization efficiency.
Performance parameters revealed favorable outcomes, with final body weight, weight gain, and feed conversion
ratio demonstrating dose-dependent improvements. Notably, birds receiving 1.5 g/kg vitamin E consumed
essentially the same quantity of feed as control birds yet achieved higher weight gain and FCR, demonstrating
superior feed conversion efficiency. Serum biochemical findings showed numerical increases in total protein and
reductions in triglycerides, with significant modulation of LDL cholesterol. Haematological parameters revealed
significant alterations in packed cell volume and differential white blood cell populations (P < 0.05),
demonstrating vitamin E's immunomodulatory properties.
From a practical and economic standpoint, these findings support vitamin E supplementation at 1.0 to 1.5 g/kg
in commercial broiler diets. The improved feed conversion efficiency achieved without increased feed
consumption represents a favorable cost-benefit ratio, as the minimal cost of vitamin E supplementation is
outweighed by economic value from improved weight gain and feed efficiency. At commercial scale, the
approximately 9% improvement in weight gain and 8% improvement in feed conversion ratio translate to
substantial cost savings per kilogram of meat produced. While 1.5 g/kg produced the most favorable outcomes,
1.0 g/kg may represent an economically optimal balance between performance benefits and supplementation
costs, depending on market conditions. The consistent improvements across multiple parameters indicate that
vitamin E supplementation provides economically meaningful value that justifies its inclusion in commercial
broiler feeding programs, particularly where marginal efficiency gains create competitive advantages.
RECOMMENDATIONS
1. Future research should employ larger sample sizes and extended production cycles to establish precise
dose-response relationships and evaluate long-term effects on growth performance, carcass
characteristics, meat quality, and economic returns across diverse production systems.
2. The immunomodulatory role of vitamin E should be investigated under stress conditions such as heat
stress, disease challenges, or high stocking densities common in commercial broiler production.
3. Studies should examine synergistic or antagonistic interactions between vitamin E and other
micronutrients, particularly selenium and vitamin C, to optimize comprehensive dietary fortification
strategies.
4. Mechanistic studies employing intestinal tissue sampling, microbiota profiling, and molecular analyses
of nutrient transporter expression would clarify the divergent effects of vitamin E on protein and fat
digestibility observed in this study.
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