Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2005
Volume 8
Issue 1
Topic:
Animal Husbandry
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Jacyno E. , Ko這dziej A. , Kaw璚ka M. , Kamyczek M. , Pietruszka A. , Elzanowski C. 2005. REPRODUCTIVE PERFORMANCE OF YOUNG BOARS RECEIVING DURING THEIR REARING INORGANIC OR ORGANIC SELENIUM+VITAMIN E IN DIETS, EJPAU 8(1), #07.
Available Online: http://www.ejpau.media.pl/volume8/issue1/art-07.html

REPRODUCTIVE PERFORMANCE OF YOUNG BOARS RECEIVING DURING THEIR REARING INORGANIC OR ORGANIC SELENIUM+VITAMIN E IN DIETS

Eugenia Jacyno1, Anita Ko這dziej2, Maria Kaw璚ka1, Marian Kamyczek3, Arkadiusz Pietruszka2, Czes豉w Elzanowski2
1 Depatrment of Pig Breeding, Faculty of Biotechnology and Animal Breeding, West Pomeranian University of Technology, Szczecin, Poland
2 Depatrment of Pig Breeding, Agricultural University of Szczecin
3 National Research Institute of Animal Production, Cracow

 

ABSTRACT

The objective of the study was the comparison the influence of the organic Se (Se-Yeast) + vitamin E and inorganic Se (Na2Se03) + vitamin E on reproductive performance of young boars. The studies were carried out on the 60 young boars of the 990 Polish synthetic line divided into 3 groups. During the test (from 70 to 180 days of age) the males received in 1 kg feed mixture: group I-0.2 mg inorganic Se + 30 mg vitamin E (standard mixture), groups II and III respectively: 0.2 and 0.4 mg organic Se + 60 mg vit. E. At 180 day of live selection index, testes volume, libido traits, semen characteristics were determined.The boars of groups II and III, in comparison with group I, reached little lower selection index, but characterized by higer (p≤0.01 and p≤0.05) testes volume, better libido, higer concentration and total number of spermatozoa in ejaculate, higer value of osmotic resistance test of acrosome membranes, lower precentage of spermatozoa with morphological defects and lower precentage of spermatozoa with morphological defects and lower aspartate aminotransferase activity.The were no statistically significant diferences between the males of the II and III groups with regard the analysed traits.

Key words: reproductive performance, selenium, vitamin E, young boars.

INTRODUCTION

Besides many other functions, selenium and its synergistic counterpart, vitamin E, are crucial for the processes of reproduction for both males and females. A positive effect of selenium + vitamin E was found in relation to sexual activity of boars, their semen quality (motility, concentration, and sperm morphology) as well as to fertilization rates [6, 7, 8, 12, 13]. As a source of selenium, the cited authors used inorganic compounds of this element (selenates and selenites). Also in practicaly feeding of livestock animals, including swine, inorganic compounds of this microelement are used.

The studies published over the last years focus mainly on organic compounds of selenium and their application in the supplementation of livestock feeding. For monogastric animals, like pigs, selenium is available both in the form of organic (seleno-amino acids) and inorganic compounds (selenates and selenites); however, the availability of organic compounds, as well as their biological efficiency, are significantly higher than those of inorganic selenium compounds. Mahan and Parret [10] found that organic selenium retention in pigs was by 85% higher than that of inorganic selenium. According to Pehrson [14], supplementation with organic forms of selenium needs an additional portion of vitamin E.Little information can be found in the available literature on the influence of organic selenium compounds on the reproduction of pigs. Studies on boars have demonstrated that organic selenium is much more positive to reproduction of the males compared with an inorganic form of this element [11].

The aim of this study was to compare reproductive performance of young boars fed during their rearing on the diet supplemented with organic or inorganic selenium compounds + vitamin E.

MATERIALS AND METHODS

Animals and feeding

The test that lasted from 70 to 180 days of age was carried out in the Central Hybridization Station in Paw這wice on 60 young boars of the 990 Polish synthetic line. The experimental males were fed on the same diet from 30th day of age (weaning date) until 70 days of age. On the 70th day, the boars were distributed into 3 groups, 20 boars each. The division into the groups was carried out with the analogues method, i.e. one boar from one litter was designated to each group. During the test, the feeding of each group was differentiated only by quantity and chemical form of selenium and vitamin E. The boars of group I received standard diet supplemented with 0.2 mg selenium in an inorganic form (Na2SeO3) and 30 mg vitamin E in 1 kg of diet [9]. The diets of the groups II and III contained the following supplements, respectively: 0.2 and 0.4 mg organic selenium (Se-Yeast) and 60 mg vitamin E in 1 kg. Chemical composition and nutritional values of the diets prepared in the form of pellets were similar (Table 1). The animals were kept in individual pens (1.0 m by 2.0 m) throughout the test. Standardised feeding was applied with permanent water supply. Daily rations were increased along with body weight gains.

Table 1. Chemical composition of diets

In 1 kg diets

Diets

I 0.2 ppm
inorganic Se

II 0.2 ppm
organic Se

III 0.4 ppm
organic Se

Metabolizable energy (MJ)*

13.0

12.9

13.0

Dry matter (g)

879

882

878

Crude ash (g)

49.9

53.5

55.4

Crude protein (g)

191

190

192

Ether extract (g)

18.8

18.6

19.1

Crude fibre (g)

27.0

27.1

26.3

N-free extractives (g)

592

593

585

Lysine (g)

10.1

10.1

10.8

Methionine (g)

3.6

3.7

4.0

Methionine + cystine (g)

6.4

6.3

6.8

Threonine (g)

6.7

6.9

7.0

Vitamin E (mg)

30.0

60.0

60.0

Additive (mg∙kg-1)
- inorganic Se
- organic Se

 
0.20
-

 
-
0.20

 
-
0.40

* Calculated from Polish Norm of Pigs Nutrition [9].

Evaluation of the boars

Selection index for live evaluation of the boars was determined with included their daily gains until 180 days of age and percentage carcass leanness, which was live evaluated using an ultrasound instrument on the 180th day of age. On the 70 and 180th day of age, testes were measured and their volume was established [20].

As from the age of 180 days, semen collections started and were continued until obtaining fully-quality ejaculates, which were then diagnosed. During the semen collection, sexual activity of the males was evaluated, measured as a number of leaps, time to effective phantom mounting, as well as the time of ejaculation.

Semen evaluation

Immediately after the collection and filtration of ejaculate, its following characteristics were determined: ejaculate volume, percentage of motile spermatozoa, concentration of sperma-tozoa in 1 cm3 (cytometric method using Brker's chamber), and total number of spermatozoa in ejaculate. Semen preparations were used to determine major and minor morphological changes of spermatozoa [2] and the rate of acrosome defects [16]. The osmotic resistance test (ORT) was performed according to Schilling and Vengust [17].In the seminal plasma, obtained by centrifugation of the liquid fraction of the semen, activity of aspartate aminotransferase (AspAT) was determined. The seminal plasma had been stored at -20°C before the analyses took place.

Chemical analyses

Basic nutritional components of feeds were analysed using standard methods [1], while amino-acids were measured using an automatic analyser (Beckman). Selenium concentration in the premix and Se-Yeast was measured with the fluorometric method [19], while vitamin E in the premix was assayed using liquid chromatography. AspAT activity in the seminal plasma was determined with the kinetic method and converted to 1.109 spermatozoa.

The results of the analysed traits of the boars were subjected to one-way ANOVA in orthogonal design using the Statistica PL software package.

RESULTS

Selection index of all the experimental groups of boars were similar, ranging within 121-127 pts. (Table 2). On the day of the test commencement, testes volume of the group I boars reached 16.5 cm3 on average and was by 3.8 and 3.0 cm3 higher than that in the groups II and III (differences statistically non-significant). On the 180th day of age, testes volume of the group III boars was by 88 cm3 (p≤0.01) and that of the group II by 52 cm3 (p≤0.05) higher as compared with the males of the group I. Time of effective mounting in the boars of the group II was by 111 sec. shorter (p≤0.05) and in the boars of the group III by 41 sec. shorter as compared with that of group I boars. The remaining libido traits (number of leaps and ejaculation time) did not differ significantly between the groups.

Table 2. Selection index, testes volume and sexsual activity of young boars

Traits

Groups

I
0.2 ppm
inorganic Se

II
0.2 ppm
organic Se

III
0.4 ppm
organic Se

SEM

Selection index (pts)

Volume of both testes (cm3)

- at 70th day of life

- at 180th day of life

Time mounting upon phantom (s)

Number of mounts

Time of ejaculation (s)

127

 

16.5

564Aa

281a

1.2

205

121

 

12.7

616a

170a

1.4

229

121

 

13.5

652A

240

1.7

215

1.33

 

0.79

18.1

20.1

0.08

6.2

Means with the same letters are significantly different: capitals - p≤0.01, small letters - p≤0.05;
SEM - standard error of means.

The semen traits presented in Table 3 are characteristic for young boars. The ejaculate volume and percentages of progressively motile spermatozoa in the ejaculates of all the groups were similar, respecively, 105-110 cm3 and 72.1-73.3%. The concentration and total number of spermatozoa in an ejaculate of the group II males were respectively by 22 and 26% higher (p≤0.05) than in the group I. On the other hand, the ejaculates of the group III showed spermatozoa concentration by 12% and total number spermatozoa by 17% (p≤0.05) higher compared with ejaculates of group I boars.The number of spermatozoa with major and minor morphological defects in the ejaculates of group II boars was, respectively, by 18.2% (p≤0.01) and 5.2% (p≤0.05) lower, while in the ejaculates of group III boars was, respectively, by 15.2 and 9.6% (p≤0.01) lower, as compared with the ejaculates of the group I boars. In the ejaculates of group III boars, the percentage of spermatozoa with minor morphological changes was also significantly lower (p≤0.05) than that in the group II. The number of spermatozoa with normal acrosome in the ejaculates remained at a relatively high and similar levels (85.0 - 87.8%), irrespective of the form or quantity of the supplemented selenium.

Table 3. Semen traits of young boars

Traits

Groups

I
0.2 ppm
inorganic Se

II
0.2 ppm
organic Se

III
0.4 ppm
organic Se

SEM

Ejaculate volume (cm3)

Motile spermatozoa (%)

Concentration of spermatozoa (n ∙ 106∙cm-3)

Total number of spermatozoa (n ∙109)

Spermatozoa with major defects (%)

Spermatozoa with minor defects (%)

Spermatozoa with normal acrosome (%)

Osmotic resistance test - ORT (%)

AspAT (mU∙10-9 spermatozoa)

105

72.1

191a

19.8ab

28.2Ab

18.6aB

85.4

63.4ab

157AB

109

73.3

246a

26.8a

10.0A

13.4ab

85.0

77.3b

83A

110

73.1

217

23.9b

13.0A

9.0Aa

87.8

74.5a

87B

1.3

0.79

12.2

1.83

1.50

1.50

1.16

1.92

9.5

Means with the same letters are significantly different: capitals - p≤0.01, small letters - p≤0.05;
SEM - standard error of means.

The (ORT) values of the spermatozoa of the boars receiving inorganic form of selenium + vitamin E (group I) was 63.4% and was by 13.9% lower (p≤0.05) than in the group II, and by 11.1% lower (p≤0.05) than in the group III.

AspAT activity in seminal plasma of the groups II and III was similar (83 and 87 mU∙10-9 sperm) and, respectively, by 74 and 70 mU∙10-9 sperm lower (p≤0.01) as compared with the seminal plasma of group I boars.

DISCUSSION

The results of our studies indicate that the chemical form of selenium supplementation is not indifferent in young boar feeding. Substituting inorganic selenium with organic selenium in the diets fed to raised boars significantly and positively influenced the development of their testes. Elevating the level of organic selenium from 0.2 to 0.4 mg per 1 kg of diet did not significantly differentiate the size of testes of the studied boars. Ko這dziej and Jacyno [7] found that elevating the level of inorganic selenium in the diet from 0.2 to 0.5 ppm was also of little effect for the development of young boars' testes.

The semen of the males receiving organic selenium-supplemented diets during raising demonstrated better quality than that of the males fed on standard rations, which contained selenium in its inorganic form (group I). Highest concentration and total number spermatozoa in the ejaculates of the males receiving Se-Yeast selenium means that selenium in its organic form was more positive for the spermatogenic epithelium of the testes of the boars than selenium of inorganic compounds. However, a stronger stimulating effect was recorded when the supplementation was 0.2 mg of organic selenium + 60 mg vitamin E per 1 kg of diet (group II).

Morphological examination of spermatozoa which included their quantitative and qualitative changes provide one of the basic and most unbiased criteria of semen evaluation. The results of the morphological appraisal of the spermatozoa show that organic selenium + vitamin E-supplementation significantly more effectively prevented both major and minor morpho-logical changes than supplementation with inorganic selenium + vitamin E. A high percentage of spermatozoa with abnormalities that was found in all the experimental groups of the presented study may have resulted from the young age of the boars, which do not attain fully mature efficiency of spermatogenic epithelium, which would otherwise balance the produ-ction of morphologically normal spermatozoa [3].

Additional data on semen quality and its fertilization ability can be obtained from the results of the osmotic resistance test (ORT). This test determines the degree of sensitivity of acrosomal membranes of spermatozoa to changes in osmotic pressure. Between the ORT value and fertilizing ability of the semen, a strict positive correlation was found [17, 18]. The values of ORT obtained in our experiment represent an additional confirmation that organic Se, in comparison with inorganic Se, exerted a more positive effect on semen quality of the boars.

Aspartate aminotransferase (AspAT) is permanently bound to the the sperm basal body, especially to mitochondrial membrane. Increased leakage of AspAT from spermatozoa to seminal plasma indicates damages in sperm cellular membrane and secondary reduction in the activity of the enzyme in the cells [4]. As a consequence, biological value of the semen is reduced.The activity of AspAT we have observed in the seminal plasma of the experimental boars suggests that the doses of organic selenium and vitamin E applied in the diet were more effective (p≤0.01) in protecting sperm membranes, compared to the dose of inorganic selenium and vitamin E applied in standard feeding. The observed high negative relationship between AspAT activity and fertility of the boars [5] allows concluding that the semen of boars receiving organic selenium in their rations (groups II and III) will have higher fertilisation ability, compared with that of the boars fed on diets supplemented with inorganic form of selenium (group I). A positive effect of inorganic selenium in terms of sperm cellular membranes protection was reported by Pratt et al. [15] and Ko這dziej and Jacyno [7].

Available literature does not provide much information on the effect of selenium chemical form (organic or inorganic) on reproductive performance of boars, including their semen traits, which impedes a discussion of our results. However, a significant, positive effect of inorganic selenium forms + vitamin E has been demonstrated in relation to qualitative and quantitative characteristics of boar semen [7, 8, 12]. Supplementation with a large dose (220 IU∙kg-1 diet) of vitamin E alone was of little effect on most of semen traits [12, 13]. This shows that these two synergistically acting antioxidants (Se and vitamin E) should be admi-nistered jointly.

An analysis of the obtained results of the groups II and III has demonstrated that increased dose of organic selenium in the diet from 0.2 to 0.4 ppm does not significantly differentiate testes volume, libido traits, and semen characteristics, except for the percentage of sperm with minor changes.

CONCLUSIONS

A supplement of 0.2 or 0.4 mg organic selenium and 60 mg vitamin E to 1 kg of ration applied in rearing young boars had a much more important effect on their reproductive performance, as compared with a supplement of 0.2 mg inorganic selenium and 30 mg vitamin E. Applied doses of organic selenium (0.2 and 0.4 mg∙kg-1 diet) did not significantly differentiate reproductive performance of young boars, which demonstrates that 0.2 mg organic selenium and 60 mg vitamin E per kg is a sufficient supplementation of diet applied in rearing boars.

ACKNOWLEDGEMENT

The study was conducted as part of the research project no. 5 PO6E 01618, financed by the state Committee for Scientific Research.

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Eugenia Jacyno
Depatrment of Pig Breeding,
Faculty of Biotechnology and Animal Breeding,
West Pomeranian University of Technology, Szczecin, Poland
Doktora Judyma 10, 71–460 Szczecin, Poland
Phone: 91-449-68-41
email: Eugenia.Jacyno@zut.edu.pl

Anita Ko這dziej
Depatrment of Pig Breeding,
Agricultural University of Szczecin
Doktora Judyma 10, 71-466 Szczecin, Poland

Maria Kaw璚ka
Depatrment of Pig Breeding,
Faculty of Biotechnology and Animal Breeding,
West Pomeranian University of Technology, Szczecin, Poland
Doktora Judyma 10, 71–460 Szczecin, Poland
Phone: 91-449-68-41
email: Maria.Kawecka@zut.edu.pl

Marian Kamyczek
National Research Institute of Animal Production, Cracow
Sarego 2, 31-047 Cracow, Poland

Arkadiusz Pietruszka
Depatrment of Pig Breeding,
Agricultural University of Szczecin
Doktora Judyma 10, 71-466 Szczecin, Poland

Czes豉w Elzanowski
Depatrment of Pig Breeding,
Agricultural University of Szczecin
Doktora Judyma 10, 71-466 Szczecin, Poland

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