|
|
|
|
Research Article
|
|
Effects of Dietary Nano-Selenium on Tissue Selenium Deposition, Antioxidant Status and Immune Functions in Layer Chicks
|
|
P. Mohapatra,
R.K. Swain,
S.K. Mishra,
T. Behera,
P. Swain,
S.S. Mishra,
N.C. Behura,
S.C. Sabat,
K. Sethy,
K. Dhama
and
P. Jayasankar
|
|
|
ABSTRACT
|
Comparative study on the effect of nano selenium (nano-Se) and sodium selenite on the growth, bioavailability, antioxidative activities, hematological and biochemical parameters, cellular and humoral immunity was done in layer chicks upto 8th week post feeding. The results showed significant differences (p<0.05) in relative weight gain and final body weight of the nano-Se treated groups upto a dose of 0.3 mg kg-1 of diet as compared to sodium selenite and control groups. However, further increase in dietary nano-Se content in feed had negative effect on weight and Relative Gain Rate (RGR). Survival rate and Feed Conversion Ratio (FCR) were not affected by dietary treatments. Chicks fed with both nano-Se and sodium selenite showed higher (p<0.05) Se content in different tissues (breast muscle, liver, kidney, pancreas, serum and feathers). However, highest value (p<0.05) of Se content in breast muscle and liver was observed in nano-Se treated groups. Selenium concentrations in serum, liver and breast muscle increased linearly and quadratically (p<0.05) as dietary Se level increased for all Se sources but its magnitude was substantially greater (p<0.05) when nano-Se was fed. Glutathione peroxidase (GSH-Px), erythrocyte catalase (CAT) and superoxide dismutase (SOD) activities were significantly different (p<0.05) in all treated groups than control. Dietary nano-Se also increased several serum biochemical and haematological parameters. In addition, it significantly increased both cellular and humoral immunity in layer chicks after 8th weeks of post feeding. In conclusion, dietary administration of nano-Se was found superior than that of inorganic sodium selenite in various aspects in layer chicks. Further extensive study for exploring absorption mechanisms, metabolic pathways, ideal dose/form of nano-Se is suggested for optimum utilization of nano-material based application of Se feeding in poultry.
|
|
|
|
How
to cite this article:
P. Mohapatra, R.K. Swain, S.K. Mishra, T. Behera, P. Swain, S.S. Mishra, N.C. Behura, S.C. Sabat, K. Sethy, K. Dhama and P. Jayasankar, 2014. Effects of Dietary Nano-Selenium on Tissue Selenium Deposition, Antioxidant Status and Immune Functions in Layer Chicks. International Journal of Pharmacology, 10: 160-167. DOI: 10.3923/ijp.2014.160.167 URL: https://scialert.net/abstract/?doi=ijp.2014.160.167
|
|
|
|
|
INTRODUCTION
The rapid development of nano-technology holds great promises for application
in medicinal and nutritional science because nano-materials have been found
to have several novel properties different to those bulk materials. Recently,
selenium (Se) has been recognized as an essential dietary nutrient. Dietary
selenium is an essential trace element for animals and humans with a variety
of biological functions (Surai, 2006). These compounds are
necessary for growth, fertility, immune system, hormone metabolism, cell growth
and antioxidant defence systems in animals and humans (Pappas
and Zoidis, 2012).
Selenium deficiency in poultry, causes some diseases which include exudative
diathesis, pancreatic dystrophy and nutritional muscular dystrophy (McDowell,
1992). Selenium is found naturally in plant feed ingredients but concentrations
vary greatly depending on both the plant species and Se status of the soil.
Therefore, poultry diets require supplementry Se in order to provide a margin
of safety against deficiency and to maintain productive performance. Both organic
and inorganic forms of selenium are used as supplements in the poultry diet.
Subsequent studies report that nano-elemental Se possesses comparable efficiency
with other Se sources (Zhang et al., 2005, 2008).
Recently nano elemental selenium which is bright red, highly stable, soluble
and of nano meter size in the redox state of zero (Se0) has attracted
wide spread attention due to its high bioavailability and low toxicity. Nanometer
particulates exhibit novel characteristics, such as great specific surface area,
high surface activity, high catalytic efficiency and strong adsorbing ability
(Zhang et al., 2001). However, little has been
done to study the effect of the novel nano-Se in layer chicks. Limited studies
on nano-Se supplementation are available and the findings are rather inconsistent
particularly as regards to several physiological effects in chicks. Thus, the
purpose of this experiment was to study effects of dietary nano-Se on growth
performance, tissue deposition, antioxidant defense system and immune functions
in layer chicks in comparison to sodium selenite.
MATERIALS AND METHODS
Selenium sources: Nano red elemental selenium particles (nano-Se) were
synthesized by Zhang et al. (2001). One milliliter
of 25 mM sodium selenite was mixed with 4 mL of 25 mM GSH containing 15 mg of
BSA for the nano-Se preparations. The pH of the mixture was adjusted to 7.2
with 1.0 M sodium hydroxide forming red elemental Se and oxidized GSH. The red
suspension was dialyzed against double-distilled water for 96 h with the water
being changed every 24 h to separate the oxidized GSH from the Nano-Se. The
final suspension containing nano-Se and BSA was lyophilized and stored at room
temperature. The size of the red elemental Se was 50-100 nm as determined by
Dynamic Light Scattering (DLS) analysis using a Zetasizer Nano ZS (Malvern Instruments,
Malvern, UK) with the average size being 80 nm. Sodium selenite (Na2SeO3)
was purchased from Sigma-Aldrich Co., USA.
Animals diet and experimental procedures: Vaccinated day old sexed commercial (BV 300) layer chicks (n = 300) were randomly allocated to six dietary treatments. Each treatment group had 2 replicates containing 25 chicks in each replicate. The chicks were randomly distributed so as to eliminate any significant difference between treatments with respect to body weight. The chicks were protected against Newcastle and infectious bursal diseases by routine vaccination. The chicks were provided 24 h free access to clean drinking water. From 0-4 weeks of age, artificial light was provided to chicks to achieve brooding temperature and further the day length was the photoperiod for the birds during chick and grower stage.
Basal diet was formulated to meet nutrient requirements according to the National
Research Council (1994) except Se for the experimental feeding period of
0-8 weeks. Samples of the experimental feed were analyzed for dry matter, crude
protein, ether extract, crude fiber, total ash and acid insoluble ash. Calcium
and phosphorus was measured according to the method modified by Talapatra
et al. (1940). The Se content of the feed samples was estimated by
using atomic absorption spectrophotometer. The ingredient composition and proximate
composition of the experimental ration is presented in Table 1.
The dietary treatments of the experiment group were presented in Table
2.
Growth and feed consumption: Weights of all the individual chicks in
each group were determined at initial and at the end of experiment.
Table 1: |
Formulations of experimental diets |
 |
Table 2: |
Concentration of selenium in experimental diets of different
treated groups |
 |
At the same time, survival was also determined by counting the individuals
in each group. The relative gain rate was calculated using the equation i.e.:
The Feed Conversion Ratio (FCR) was expressed as:
Biochemical analysis: Blood and serum samples were collected at 8th weeks of post feeding for biochemical analysis. The serum biochemical indices determined were serum glucose, cholesterol, urea, alkaline phosphate (ALP), aspirate amino transferase (AST), alanine amino transferase (ALT) total protein, albumin, globulin, calcium (Ca) and phosphorus (P) were determined by using Crest biosystems (Goa, India) Kit.
Haematological parameters: Blood and serum samples were collected at
8th week of post feeding for haematological studies. The haemoglobin content
and Packed Cell Volume (PCV) were determined as per methods described by Schalm
et al. (1975) and Jain (1986), respectively.
Total Erythrocyte Count (TEC) was estimated using Neubaurs hemocytometer.
Processing of organs: After 8th week of post feeding, 15 birds were
randomly chosen from each treatment and slaughtered for collection of liver,
breast muscles, pancreas, kidney, feathers, spleen, bursa of fabricius and thymus.
The birds were kept off fed overnight before bleeding and only water was provided.
The live weight of the birds was recorded as pre slaughter weight. The chicks
were bled by modified Koshers method (Panda and Mohapatra,
1989). Spleen, bursa of fabricius and thymus were clipped from the viscera
with a pair of scissors by holding with a pair of forceps. Spleen, bursa of
fabricius and thymus were weighed in a top pan electronic balance.
Selenium content in different tissues: The collected liver, breast muscles, pancreas, kidney and feathers samples were oven dried at 100°C for 24 h and finely ground. The Se content in the liver, breast muscles, pancreas, kidney and feathers samples were determined by digesting 0.5 g samples and 1 mL of serum samples at 120°C with 5 mL concentrate HNO3 for 1 h using KEL plus digestion system. The digested samples were cooled and further digested with 30% H2O2 at 200°C. The process continued until the content appeared clear and colorless. The digested samples were filtered into a volumetric flask. The contents of digestion tubes were repeatedly washed with triple distilled water to obtain complete extract of the mineral.
Cellular immunity: At 8th weeks of post feeding, 5 birds (in duplicate)
in each treated groups were injected intra dermally in the comb with 100 μg
of Phytohaemaglutinin-P (PHAP) in 0.1 mL of normal saline to measure the cellular
immune response by Cutaneous Basophilic Hypersensitivity (CBH) test (Edelman
et al., 1986). The thickness of comb was measured using digital caliper
before inoculation and 24 h post inoculation and CBH response was calculated
using the equation:
Humoral immunity: The measure of humoral immunity was carried out as
per the method described by Abdallah et al. (2009).
Sheep Red Blood Cells (SRBCs) were used as test antigens to quantitatively analyze
specific antibody response as measure of humoral immunity. At 8th weeks of post
feeding, chicks from each groups (in triplicate) were immunized intravenously
via., a wing vein with 0.07 mL packed RBC mixed with 0.93 mL physiological saline
(0.9% NaCl) for measurement of primary response. The SRBCs were obtained in
heparin solution from local sheep (reared at Instructional Livestock Farm, Bhubaneswar,
Odisha) and washed three times in physiological saline. Seven days following
the antigen challenge, blood samples were collected and serum samples were used
to measure humoral immunity. Antibody production to SRBCs was measured using
haemagglutination technique with microtitre plate U shape of 96 wells plates
according to Bachman and Mashaly (1986) and Kai
et al. (1988). All SRBCs antibody titers were expressed as log2
of the reciprocal of the highest serum dilution causing agglutination of SRBCs.
Preparation of erythrocyte pellet: Five milliliter of whole blood was collected into sterilized micro-centrifuge tube containing 0.75 mL of acid citrate dextrose (ACD; citric acid 8.0 g: Sodium citrate 22.0 g and dextrose 25.0 g and volume made to 1 L in distilled water) as anticoagulant. The blood samples were centrifuged at 3000xg for 10 min at 4°C, plasma and buffy coats were separated. The resulting erythrocyte pellet was washed thrice with phosphate buffer saline (PBS, pH 7.4). RBC diluted to 1:1 in PBS was used for the estimation of haemoglobin. For the estimation of catalase, SOD, lipid peroxidation (LPO) and glutathione peroxidase (GSH-Px), 1 mL of the 1:1 diluted RBCs in PBS were mixed with 9 mL distilled water to prepare a haemolysate of 1:20 dilution.
Estimation of antioxidant enzymes: Different antioxidant enzymatic activities
such as Glutathione peroxidase (GSH-Px) activity by the method of Paglia
and Valentine (1967) Super Oxide Dismutase (SOD) activity of RBCs were measured
using NBT assays by Masayasu and Hiroshi (1979) and catalase
was assayed in erythrocytes by the method of Bergmayer (1983).
Statistical analysis: The SAS (1991) software
(version 6.12) was used to analyze the data.
RESULTS
Body weight and FCR: The weekly average body weight and FCR of layer
chicks under different treated groups upto 8th week of post feeding were presented
in Table 3. At the beginning upto 3rd week of post feeding,
no significant difference was observed in the initial weight between different
treated groups and the control. However, there was significant difference (p<0.05)
in RGR and final weight of all different treated groups (T1, T2,
T3, T4 and T5) as compared to control group
after 8th weeks of post feeding. Moreover, RGR and final weight of T2,
T3 and T4 group were significantly increased as compared
to T1 and T6 group. However, RGR and final weight in T6
group was higher as compared to T1. Survival rate and FCR were not
affected by the dietary treatments after 8th week of post feeding.
Serum biochemical parameters: Serum biochemical parameters viz., glucose, cholesterol, triglycerides, total protein, albumin, globulin, urea, SGPT, SGOT, ALP, calcium and phosphorus at eight weeks of age of layer chicks are presented in the Table 4. Serum glucose, total protein, globulin, SGOT, Urea levels were increased linearly and quadratically (p<0.05) starting from control to T1, T2, T3, T4 and T5 groups. Whereas, serum cholesterol, triglyceride, A/G ratio, ALP decreased linearly (p<0.05) starting from control to T1, T2, T3, T4 and T5 groups. In addition to that, serum albumin, Ca and p-level of the layer chicks showed no significant difference (p>0.05) in all the treated groups along with the control group.
Immunity status: Antibody titer against SRBC and CBH response (Table
5) and weight of lymphoid organs (Table 6) were used as
measures to study the immunity status of the layer chicks.
Table 3: |
Growth performance and feed utilization of layer chicks supplemented
with different Se sources (nano-Se and sodium selenite of different concentration)
and without Se (control) |
 |
RGR: Relative gain rate, FCR: Feed conversion ratio. Results
were presented as Mean±SE of triplicate observations. Means in the
same row with different letters were significantly different (p<0.05) |
Table 4: |
Serum biochemical profile of layer chicks supplemented with
different dietary treatments |
 |
Values bearing different superscripts in a row are significantly
different (p<0.05) |
Table 5: |
Immunity status of layer birds under different dietary treatments |
 |
Values bearing different superscripts in a row differ significantly
(p<0.05) |
Table 6: |
Lymphoid organs (% of live weight) of layer birds in different
treated groups |
 |
Values bearing different superscripts in a row differ significantly
(p<0.05) |
Table 7: |
Antioxidant enzyme activities in different treated groups
supplemented with different selenium sources of layer chicks |
 |
Values bearing different superscripts in a row differ significantly
(p<0.05) |
Table 8: |
Effect of different dietary selenium sources and levels on
different haematological parameters of layer chicks |
 |
Mean values within a row with different superscripts differ
significantly (p<0.05) |
The antibody titers (log2) against SRBCs immunization of 8th week
chicks were significantly higher (p<0.05) in T2, T3,
T4 and T5 groups as compared to T1 and control
group. The CBH response was found to be significantly higher (p<0.05) in
T2, T3, T4 and T5 groups as compared
to T1 and control group. However, T1 group showed higher
antibody response as compared to control against both SRBCs and CBH immunizations.
The average weights of lymphoid organs viz., spleen, bursa and thymus was expressed
as percentage of live body weight after 8th week of post feeding, showed no
significant (p>0.05) difference among different treated groups.
Antioxidant enzyme activities: The antioxidant enzyme activities of layer chicks were presented in Table 7. Erythrocyte catalase activity were significantly (p<0.05) higher in T3, T4, T5 and T6 as compared to T1 and control group. Glutathione peroxidase (GPX) activities were significantly (p<0.05) higher in T3, T4, T5 and T6 as compared to T1 and control. However, both GPX and catalase activities were significantly higher in T1 as compared to untreated control group. Similarly super oxide dismutase activity were significantly (p<0.05) higher in T4, T5 and T6 group as compared to other treated and control groups. Hematological parameters: Different hematological parameters of different treated groups are presented in Table 8. The haemoglobin content, TEC and PVC values were significantly (p>0.05) higher in all the treated groups (T1, T2, T3, T4 and T5) than the control group. However, there is no significance difference among different treated groups. Bioavailability of selenium: The bioavailability of Se in different tissues of layer chicks in different dietary treated groups is presented in Table 9. The Se levels in serum, liver, breast muscle, pancreas, kidney and feathers were significantly higher (in increasing order with respect to increasing selenium concentration in the diet) in all the nano-Se treated groups (T2, T3, T4 and T5) than the untreated control and sodium selenite treated group (T1). However, T1 group showed significantly higher selenium deposition in liver, pancreas and kidney than the untreated control group.
Table 9: |
Effect of different dietary selenium sources and level on
selenium concentration in serum and tissues of layer chicks |
 |
Mean values within a row with different superscripts differ
significantly (p<0.05) |
DISCUSSION
The supplementation of feed with selenium is usually limited to selenides such
as sodium selenite and selenium containing organic compounds. It was found that
nano-Se had similar or higher bioavailability and much less toxicity in mice,
rat, broiler and goat compared with selenite (Zhang et
al., 2001, 2005; Gao et
al., 2002; Jia et al., 2005; Wang
et al., 2007; Shi et al., 2011; Zhou
and Wang, 2011). The present study showed that the growth performance of
chicks was affected after 3rd weeks of post feeding by dietary Se level. In
contrast to current results, some reports demonstrated no effect of Se source
or Se level on daily gain, feed intake or gain:feed ratio (Payne
and Southern, 2005; Yoon et al., 2007). The
differences were possibly due to the background of Se in the feedstuffs. A concentration
of 0.15 mg Se/kg diet is recommended for broiler chickens (National
Research Council, 1994). However, the basal diet used in this experiment
contained only 0.075 mg Se/kg diet which was far lower than the requirements.
Poultry diets deficient in selenium resulted in poor growth and development,
increased mortality and reduced egg production, decreased hatchability (Kim
and Mahan, 2003). The present result proved this point and the group not
supplemented with any forms of selenium showed the symptoms of selenium deficiency
such as lower weight gain and RGR values. On the other hand, dietary Se levels
exceeding 0.5 mg kg-1 might impair the growth while clinical symptoms
of Se toxicity appear above 3-5 mg Se/g of diet (Kirchgessner
et al., 1997). However, in the present study, increased growth performance
was observed when 0.6 mg kg-1 of supplemental nano-Se was fed. This
suggests that the addition of 0.6 mg kg-1 of nano-Se was acceptable
in avian feeding. The results indicated that the range between optimal and toxic
dietary levels of nano-Se was wider than that of sodium selenite.
It was obvious that the Se contents in layer chick tissues such as breast muscle,
liver, kidney, pancreas and feathers were markedly increased with the addition
of dietary nano-Se in treated groups than the sodium selenite and untreated
control groups. Moreover, increased selenium deposition was found with increasing
nano-Se content in the diet. In general, animal study trials demonstrated that
bioavailability of nano-Se was higher than that of inorganic forms (sodium selenite)
(Zhang et al., 2001). Thus, Se bioavailability
depended not only on its absorption by the intestine but also on its conversion
to a biologically active form (Foster and Sumar, 1995).
There are several reports of Se supplementation to increase the breast, liver,
or plasma Se levels (Downs et al., 2000; Spears
et al., 2003).
Selenium has a number of biological functions in animals and the most important
action is its antioxidant effect (Levander and Burk, 1994).
The results of present study also showed higher GSH-Px activity, SOD and catalase
activities in erythrocytes of layered chicks as compared to the sodium selenite
and untreated control groups. This suggested that serum GSH-Px activity seemed
to be reflective of its dietary Se level but additional dietary Se did not stimulated
further activity of the enzyme. The present finding indicated that the nano-Se
had higher Se retention in liver, pancreas and breast muscle and was consistent
with previously published results in goats (Shi et al.,
2011). Increasing the Se content of food for human consumption by manipulating
source and level of Se supplementation to livestock has been area of interest
to food scientists (Zhan et al., 2007; Wang
and Xu, 2008). The results indicated that nano-Se was more greatly accumulated
in breast muscle than the sodium selenite.
An improved antioxidant system of the chick may also enhance immune system
function which is extremely important at this point in physiological development.
In the present study, dietary supplementation of nano-Se increased both humoral
and cellular immunity as measured by antibody titer against SRBC, CBH responses
and gave higher antibody response than that of sodium selenite and untreated
control groups. However, different dietary selenium sources did not affect weight
of different lymphoid organs and different haematological parameters such as
haemoglobin content, TEC and PVC values. In addition to that, different physiological
parameters such as serum glucose, total protein, globulin, SGOT, urea levels
were increased linearly and quadratically (p<0.05) with increase in concentration
of nano-Se in diet. However, there was no effect on serum cholesterol, triglyceride,
A/G ratio, ALP due to dietary administrations of nano-Se in layered chicks.
Similarly, the findings of Yang et al. (2012)
revealed that the aspartate amino transferase, alkaline phosphatase (ALP), total
protein, globulin, total bilirubin, glucose, urea, total cholesterol, triglyceride
and high density lipoprotein levels were observed to be non-significant between
control and Se supplemented group in chicks.
The different physiological effects of nano-Se and sodium selenite were probably
related to the different absorption process and metabolic pathways. It has been
reported that nanoparticle show new characteristics of transport and uptake
and exhibit higher absorption efficiencies (Liao et
al., 2010). They suggested that the superior performance of nanoparticles
may be attributed to their smaller particle size and larger surface area, increased
mucosal permeability, improved intestinal absorption and tissue depositions.
CONCLUSION The present study had demonstrated that dietary administration of nano-Se could improve the final weight, relative gain rate, antioxidant status (GSH-Px activities, SOD and erythrocyte catalase activities) and selenium deposition in several tissues especially breast muscle of layer chicks. Moreover, nano-Se appeared to be more effective (p<0.05) for than that of inorganic sodium selenite in increasing different biochemical parameters, haematological parameters, cellular and humoral immunity. The results also showed that the range of optimum dietary levels of nano-Se was wider than that of sodium selenite and nano-Se of 0.3 mg kg-1 of dry diet is the optimum dose for getting better physiological effects in layer chicks. Further supportive study is needed to explore absorption mechanism, metabolic pathways, ideal dose and form of nano-Se that should be fed to poultry under commercial conditions. ACKNOWLEDGMENTS Authors are highly thankful to All India coordinated research project on Improvement of feed resources and nutrient utilization in raising animal production of ICAR, New Delhi, INSPIRE Fellowship under INSPIRE Program of the Department of Science and Technology (DST), New Delhi and National Fellow scheme of ICAR, New Delhi, for providing all financial support and other facilities to carry out this study.
|
REFERENCES |
1: Abdallah, A.G., O.M. El-Husseiny and K.O. Abdel-Latif, 2009. Influence of some dietary organic mineral supplementations on broiler performance. Int. J. Poult. Sci., 8: 291-298. CrossRef | Direct Link |
2: Bachman, S.E. and M.M. Mashaly, 1986. Relationship between circulating thyroid hormones and humoral immunity in immature male chickens. Dev. Comp. Immunol., 10: 395-403. CrossRef | PubMed | Direct Link |
3: Bergmayer, H.U., 1983. UV Method of Catalase Assay. In: Methods of Enzymatic Analysis, Volume 2: Samples, Reagents, Assessment of Results, Bergmayer, H.U. (Ed.). 3rd Edn., Verlag Chemie, Weinheim, Germany, ISBN-13: 978-0895732323,.
4: Downs, K.M., J.B. Hess and S.F. Bilgili, 2000. Selenium source effect on broiler carcass characteristics, meat quality and drip loss. J. Applied Anim. Res., 18: 61-71. CrossRef | Direct Link |
5: Edelman, A.S., P.I. Sanchez, M.E. Robinson, G.M. Hochwald and G.J. Thorbecke, 1986. Primary and secondary wattle swelling response to phytohemagglutinin as a measure of immunocompetence in chickens. Avian Dis., 30: 105-111. Direct Link |
6: Foster, L.H. and S. Sumar, 1995. Selenium in the environment, food and health. Nutr. Food Sci., 5: 17-23. CrossRef | Direct Link |
7: Gao, X., J. Zhang and L. Zhang, 2002. Hollow sphere selenium nanoparticles: Their in-vitro anti hydroxyl radical effect. Adv. Mater., 14: 290-293. CrossRef | Direct Link |
8: Jain, N.C., 1986. Schalm's Veterinary Hematology. 4th Edn., Lea and Febigir, Philadelphia, PA., USA., Pages: 600.
9: Jia, X., N. Li and J. Chen, 2005. A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats. Life Sci., 76: 1989-2003. CrossRef | Direct Link |
10: Kai, O., N. Nagase, N. Ishikawa, K. Suzuki, T. Kakegawa and K. Sato, 1988. Effects of propylthiouracil (PTU) on the immunological status of the chicken. Dev. Comp. Immuno., 12: 145-156. PubMed |
11: Kim, Y.Y. and D.C. Mahan, 2003. Biological aspects of selenium in farm animals. Asian-Australas. J. Anim. Sci., 16: 435-444. CrossRef | Direct Link |
12: Kirchgessner, M., S. Gabler and W. Windisch, 1997. Homeostatic adjustments of selenium metabolism and tissue selenium to widely varying selenium supply in 75Se labeled rats. J. Anim. Physiol. Anim. Nutr., 78: 20-30. CrossRef | Direct Link |
13: Levander, O.A. and R.F. Burk, 1994. Selenium. In: Modern Nutrition in Health and Disease, Shils, M.E., J.A. Olson and M. Shike (Eds.). Lea and Febiger, Philadelphia.
14: McDowell, L.R., 1992. Minerals in Animal and Human Nutrition. 2nd Edn., Academic Press Inc., San Diego, CA., USA., ISBN-13: 9780444513670, pp: 284-332.
15: Masayasu, M. and Y. Hiroshi, 1979. A simplified assay method of superoxide dismutase activity for clinical use. Clin. Chim. Acta, 92: 337-342. CrossRef | PubMed | Direct Link |
16: NRC., 1994. Nutrient Requirements of Poultry. 9th Rev. Edn., National Academy Press, Washington, DC., USA., ISBN-13: 978-0309048927, Pages: 176.
17: Paglia, D.E. and W.N. Valentine, 1967. Studies on the quantitative and qualitative characterization of erythrocyte glutathione peroxidase. J. Lab. Clin. Med., 70: 158-169. CrossRef | PubMed | Direct Link |
18: Panda, B. and S.C. Mohapatra, 1989. Bleeding of Poultry Modified by Kosher's Method, Poultry Production. ICAR Publication, New Delhi, Pages: 121.
19: Pappas, A.C. and E. Zoidis, 2012. The Role of Selenium in Chicken Physiology: New Insights. In: Chickens: Physiology, Diseases and Farming Practices, Kapur, I. and A. Mehra (Eds.). Nova Science Publishers Inc., New York, USA., ISBN-13: 9781620810279, pp: 51-69.
20: Payne, R.L. and L.L. Southern, 2005. Comparison of inorganic and organic selenium sources for broilers. Poult. Sci., 84: 898-902. CrossRef | Direct Link |
21: SAS., 1991. SAS System for Regression. 2nd Edn., SAS Institute Inc., Cary, NC., USA., Pages: 210.
22: Schalm, O.W., N.C. Jain and E.J. Carroll, 1975. Veterinary Haematology. 3rd Edn., Lea and Febiger, Washington Square, Philadelphia, USA., pp: 66-78.
23: Shi, L., W. Xun, W. Yue, C. Zhang and Y. Ren et al., 2011. Effect of sodium selenite, Se-yeast and nano-elemental selenium on growth performance, Se concentration and antioxidant status in growing male goats. Small Rumin. Res., 96: 49-52. CrossRef | Direct Link |
24: Spears, J.W., J. Grimes, K. Lloyd and T.L. Ward, 2003. Efficacy of a novel organic selenium compound (zinc-l-selenomethionine, available Se) in broiler chicks. Proceedings of the 1st Congress of the Latin American Annual Nutrition College, August 18-23, 2003, Cancun, Mexico, pp: 197-198.
25: Surai, P.F., 2006. Selenium in Nutrition and Health. 1st Edn. Nottingham University Press, Nottingham, UK.
26: Talapatra, S.K., S.N. Ray and K.C. Sen, 1940. Estimation of phosphorus, chlorine, calcium, magnesium, sodium and potassium in foodstuffs. Indian J. Vet. Sci. Anim. Husb., 10: 243-246.
27: Wang, H.L., J.S. Zhang and H.Q. Yu, 2007. Elemental selenium at nano size possesses lower toxicity without compromising the fundamental effect on selenoenzymes: Comparison with selenomethionine in mice. Free Radical Biol. Med., 42: 1524-1533. CrossRef | Direct Link |
28: Wang, Y.B. and B.H. Xu, 2008. Effect of different selenium source (sodium selenite and selenium yeast) on broiler chickens. Anim. Feed Sci. Tech., 144: 306-314. CrossRef | Direct Link |
29: Yang, Y.R., F.C. Meng, P. Wang, Y.B. Jiang and Q. Yin et al., 2012. Effect of organic and inorganic selenium supplementation on growth performance, meat quality and antioxidant property of broilers. Afr. J. Biotechnol., 11: 3031-3036. Direct Link |
30: Yoon, I., T.M. Werner and J.M. Butler, 2007. Effect of source and concentration of selenium on growth performance and selenium retention in broiler chickens. Poult. Sci., 86: 727-730. CrossRef | Direct Link |
31: Zhan, X.A., M. Wang, R.Q. Zhao, W.F. Li and Z.R. Xu, 2007. Effects of different selenium source on selenium distribution, loin quality and antioxidant status in finishing pigs. Anim. Feed Sci. Technol., 132: 202-211. CrossRef | Direct Link |
32: Zhang, J.S., X.Y. Gao, L.D. Zhang and Y.P. Bao, 2001. Biological effects of a nano red elemental selenium. BioFactors, 15: 27-38. CrossRef | Direct Link |
33: Zhang, J.S., H.L. Wang, X.X. Yan and L. Zhang, 2005. Comparison of short-term toxicity between Nano-Se and selenite in mice. Life Sci., 76: 1099-1109. CrossRef | Direct Link |
34: Zhang, J.S., X.F. Wang and T.W. Xu, 2008. Elemental selenium at nano size (Nano-Se) as a potential chemopreventive agent with reduced risk of selenium toxicity: Comparison with Se-methylselenocysteine in mice. Toxicol. Sci., 101: 22-31. CrossRef | Direct Link |
35: Zhou, X. and Y. Wang, 2011. Influence of dietary nano elemental selenium on growth performance, tissue selenium distribution, meat quality and glutathione peroxidase activity in Guangxi Yellow chicken. Poult. Sci., 90: 680-686. CrossRef | PubMed | Direct Link |
36: Liao, C.D., W.L. Hung, K.C. Jan, A.I. Yeh, C.T. Ho and L.S. Hwang, 2010. Nano/sub-microsized lignan glycosides from sesame meal exhibit higher transport and absorption efficiency in Caco-2 cell monolayer. Food Chem., 119: 896-902. CrossRef | Direct Link |
|
|
|
 |