ISSN 1313 - 8820Volume 5, Number 4

December 2013

2013

Scope and policy of the journalAgricultural Science and Technology /AST/ – an International Scientific Journal of Agricultural and Technology Sciences is published in English in one volume of 4 issues per year, as a printed journal and in electronic form. The policy of the journal is to publish original papers, reviews and short communications covering the aspects of agriculture related with life sciences and modern technologies. It will offer opportunities to address the global needs relating to food and environment, health, exploit the technology to provide innovative products and sustainable development. Papers will be considered in aspects of both fundamental and applied science in the areas of Genetics and Breeding, Nutrition and Physiology, Production Systems, Agriculture and Environment and Product Quality and Safety. Other categories closely related to the above topics could be considered by the editors. The detailed information of the journal is available at the website. Proceedings of scientific meetings and conference reports will be considered for special issues.

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Editor-in-Chief

Tsanko YablanskiFaculty of AgricultureTrakia University, Stara ZagoraBulgaria

Co-Editor-in-Chief

Radoslav SlavovFaculty of AgricultureTrakia University, Stara ZagoraBulgaria

Editors and Sections

Genetics and Breeding

Atanas Atanasov (Bulgaria)Ihsan Soysal (Turkey)Max Rothschild (USA)Stoicho Metodiev (Bulgaria)

Nutrition and Physiology

Nikolai Todorov (Bulgaria)Peter Surai (UK)Zervas Georgios (Greece)Ivan Varlyakov (Bulgaria)

Production Systems

Dimitar Pavlov (Bulgaria)Dimitar Panaiotov (Bulgaria)Banko Banev (Bulgaria)Georgy Zhelyazkov (Bulgaria)

Agriculture and Environment

Georgi Petkov (Bulgaria)Ramesh Kanwar (USA)

Product Quality and Safety

Marin Kabakchiev (Bulgaria)Stefan Denev (Bulgaria)Vasil Atanasov (Bulgaria)

English Editor

Yanka Ivanova (Bulgaria)

2013

ISSN 1313 - 8820 Volume 5, Number 4December 2013

Blood parameters in yearling sheep fed Paulownia (Paulownia spp.) leaves

I. Varlyakov*, V. Radev, T. Slavov, G. Ganchev

Department of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. A physiological experiment was conducted with three yearling sheep, Stara Zagora x Pleven Blackhead crosses, to establish the effect of feeding Paulownia elongatа leaves on some blood parameters. The trial consisted of two periods: control and experimental. During the control period, yearling sheep were fed a ration of 1 kg barley and 1 kg meadow hay, and during the experimental period – dried Paulownia elongatа leaves. Blood samples were collected from v. jugularis externa before feeding and 2.5 hours after feeding during both periods after allowing 10-day adaptation to the respective diet. The studied parameters were erythrocyte counts, leukocyte counts, blood glucose, total protein, albumin and globulins. The intake of Paulownia leaves resulted in statistically significant reduction in erythrocyte (p<0.05) and leukocyte counts (p<0.001). This was most pronounced in the postprandial hours. Paulownia leaves also provoked increased total serum protein concentrations on the account of both higher albumin and globulins. The albumin/globulin ratio was 0.29 regardless of the type of diet or the time of sampling – prior to or after feeding.

Keywords: sheep digestion, Paulownia, sheep, blood parameters

AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 5, No 4, pp , 2013405 - 409

Introduction swine rations for growing and finishing pigs (Boying, 1995). Hongfu et al. (1995) evaluated fallen Paulowina leaves for degradability using the nylon bag technique and concluded that the nutritive value Nowadays, plant protein availability, including for animal of fallen leaves was superior to that of rice or wheat straw. nutrition purposes is becoming increasingly deficient. The problem

Paulownia foliage can be used for feeding goats under is not only local, but is observed at a global scale. It resulted in confinement in China (Zhu et al., 1986). Mueller et al (2001) suggest utilisation of non-traditional feed sources – leaves, fruits, seeds etc. that the lamina of the Paulownia species tested (P. tomentosa, P. During the last years, the Paulownia tree, also known as empress fortunei, P. elongata) are highly palatable and possess adequate tree, tree of Adam, dragon tree, has become popular in Bulgaria. The herbage quality for goat browse. Clones of P. elongate demonstrated trees are grown for their wood that serves for making furniture, superior early growth characteristics and in some cases superior musical instruments, floorings, wall panels etc. In different parts of herbage quality compared with other Paulownia species. One the worlds, attempts to use its leaves for animal feed are reported a aspect of forage quality that is yet to be assessed is that of anti-long time ago. It was found that the leaves could be used as a fodder quality agents such as phenolic compounds. Phenolic compounds for different farm animals (Zhaohua, 1987) due to their varied such as tannins can interfere with digestion in the rumen and reduce biochemical composition. According El-Showk and El-Showk (2003) palatability and the potential feeding value of the forage (Kumar and they are rich in minerals like calcium (2.1%), zinc (0.9%), Singh, 1984). Nevertheless it has been reported (Mehansho et al., phosphorus (0.6%), iron (0.6%) and others. Koleva et al. (2011a) 1987; Austin et al., 1989) that goats have the ability to overcome establish that Paulownia leaves composition, cultivated in Bulgaria these potential difficulties due to detoxifying enzymes in the saliva. contain 8.8% protein and 15.1% cellulose. They suggest to be used In the trials the goats readily consumed the lamina of all Paulownia as a new, alternative fodder because of rich source of macro and species. Thus it is unlikely that palatability and subsequently DM microelements. The leaves of Paulownia contain protein, rich in intake would be reduced. The next stage of research should address amino acids glutamic (16.04%) and asparagine acid (11.30%), and questions of animal performance and the presence of anti-quality essential amino acids. The content of limiting amino acids as a agents in the forage. percentage of protein is high, which surpasses all used in Bulgarian

The purpose of the present experiment was to establish leaf fodder. The data obtained from the analysis of Koleva et al. whether feeding yearling sheep with Paulownia elongatа leaves (2011b) show that the leaves of Paulownia elongata can be used as would have some adverse effect on some blood parameters with the raw material for feeding ruminants and certain monogastric animals prospective aim to use them as a sole dietary source.(such as pregnant pigs).

The genus Paulownia contains several species which exhibit rapid juvenile growth and other characteristics that justify research

Material and methodsinto their potential use in meat goat feeding systems. Chinese researchers have studied various aspects of Paulownia agroforestry systems that include crops and the use of fallen leaves for feeding A physiological experiment was conducted with three yearling swine and ruminants. Paulownia/cropping systems with corn, sheep, Stara Zagora x Pleven Blackhead crosses in the cotton, millet, wheat, soy bean and sweet potato have been reported Experimental Base of Animal Physiology Unit at the Faculty of by Huo (1992). Fallen Paulownia leaves (senescent leaves that Agriculture, Trakia University - Stara Zagora. The average live have dropped from trees) were used as a low-cost fodder source in weight of animals at the beginning was 55.4 kg. They were reared

405

* e-mail: i.v@dir.bg

406

indoor, in individual boxes with constant access to drinking water The time course of changes in erythrocyte counts (Figure 1) and salt licks. was the same for both rations – reduction after feeding. The lowest

The trial consisted of two periods: control and experimental. erythrocyte counts were established after feeding sheep with Feed was offered twice daily – at 8 AM and 1 PM. During the control Paulownia leaves, the difference being with low statistically period, yearling sheep were fed a ration of 1 kg barley and 1 kg significance level.meadow hay. During the experimental period they were given ad In their research, Nedeva et al. (2008) and Grigorova et al. libitum dried Paulownia elongatа leaves gathered in 2010 after the (2009) did not establish a statistically significant difference between November leaf drop. The chemical composition of the two rations is erythrocyte counts and haemoglobin content in yearling sheep after shown in Table 1. supplemented of a ration containing 60% concentrate and 40%

roughage with Hostazym C100. The same trend was observed: reduction in erythrocyte counts after feeding at a substantially lower extent, and all values were within the reference ranges for sheep.

In previous studies of ours with buffalo calves, the supplementation of Hostazym C100 to a ratio with higher proportion of roughage has increased erythrocyte counts (р<0.05) but total leukocyte counts were not altered (Radev et al., 2009).

The results for total leukocyte counts (Figure 2) demonstrated that feeding the baseline ration has resulted in slight increase after feeding (postprandial leukocytosis). In leukocytes, there was a comparable trend towards reduction after feeding the Paulownia leaves ration. This was especially marked immediately after feed Blood samples were collected from v. jugularis externa before

9intake – 5.65 10 /l. The differences vs pre-prandial hours were of feeding and 2.5 hours after feeding during both periods after moderate statistical significance while vs the baseline ration – highly allowing 10-day adaptation to diets. The studied parameters were significant (p<0.001).erythrocyte counts, leukocyte counts, blood glucose, total protein,

albumin and globulins. They were assayed according to routine methods described elsewhere (Sivkova, 2007).

The results were statistically processed using Statistica for Windows, and graphs were drawn in Microsoft Excel 2007.

Results and discussion

The data from Table 1 showed that the amount of protein in Paulownia elongatа leaves was lower compared to some main cereal crops such as wheat (14.2%), rye (12.7%), barley (12.3%) and corn (10.7%), which are largely used in fodder production (Мourgov et al.,1995). By itself, this fact is no reason for concern, as ruminants are able to produce their "own" microbial protein. We have tried to determine whether our local sheep breeds were able to adapt to a nutrient source non-traditional for our latitude with regard to its potential use for feed. The tests of dietary supplemented enzymatic preparaton

The data for complete blood counts demonstrated that total Hostazym C100 revealed that it increased blood leukocyte counts at leukocyte counts (Figure. 2) after feeding both rations were within a lower extent before feeding (р<0.05) and more considerably

9the reference range (5-9 10 /l), whereas erythrocytes, except for the (р<0.01) two and a half hours after feeding (Nedeva et al., 2008; baseline ration in pre-prandial hours were under the lower limit of the Grigorova et al., 2009). The established inhibiting effect of

12normal range (8–10 /l, Figure 1). Paulownia leaves on haematopoiesis should be further confirmed in additional integral studies, taking into consideration the decrease both in erythrocytes and leukocytes. At present, there are not enough data to make any reliable conclusions.

Blood glucose levels are presented on Figure 3. They varied between 3.48 mmol/l and 4.57 mmol/l and were within the reference range. The analysis of data showed that regardless of the ration, blood glucose maintained similar concentrations before and after feeding. During the experimental period, blood glucose decreased significantly (p<0.001), providing convincing evidence for the inhibiting effect of Paulownia leaves on rumen digestion processes. It is known that in ruminants, more than 30% of liver glucose is synthesised from amino acids (Bergman, 1973), no more than 10% - from glycerol (Bergman, 1971) and from 36 to 76% - from propionic acid (Seal and Reynolds, 1993). In previous experiments of ours, the tests on various nutritional supplements have established an almost

Table 1. Chemical composition of feeds

Feed Crudeprotein

Crudefibre

Crudefat

DM (%)Chemical composition (%)

Meadow hay

Barley mash

Paulownia leaves

88.20

89.90

91.75

9.03

9.60

8.12

28.30

5.00

37.44

1.90

1.70

0.86

Figure 1. Blood erythrocyte counts

10

88.22

7.54 7.36

5.946

4

2

0Paulownia leavesControl ration

12/10 l

0 h 2.5 h

Figure 2. Blood leukocyte counts

7.1 7.35 6.68

0.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

Paulownia leavesControl ration

9/10 l

0 h 2.5 h

5.65

407

functional relationship between blood glucose levels and the molar protein concentrations by about 20 g/l higher, but a comparable ratio of volatile fatty acids, especially that of acetate to propionate tendency towards decrease after feeding (Slavov, 2013).(Slavov, 2013). The increase in the relative share of acetic acid and In a series of experiments on the effect of various enzymatic decreased proportion of propionic acid resulted in lower blood preparations supplemented to the ration, a unidirectional influence glucose concentrations. consisting in increased total serum protein concentrations was

The studies on the effect of enzymatic preparation on blood established. Sivkova et al. (2006) have studied the effect of the parameters are few. Hristov et al. (2000) demonstrated that the enzymatic preparation Xibeten-Cel added to four different diets on addition of enzymes did not influence blood glucose and urea total blood proteins before and after feeding. The highest levels were concentrations. Todorova et al. (2009) found out that the observed with the diet consisting of alfalfa hay and concentrate. supplementation of concentrate feed for lambs with the enzymatic Although Nedeva et al. (2008) and Grigorova et al. (2009) did not preparation Hostazym X100 resulted in statistically significantly establish statistically significant differences, they reported that the lower blood glucose (р<0.01), attributed to the more enhanced dietary supplementation of Hostazym C100 results in a clear metabolism rate in treated animals. Having compared equal doses tendency towards higher blood total protein concentrations.of two different enzymatic preparations, Sivkova (2007) observed The analysis of protein factions would include both blood that Xybeten reduced blood glucose before (p<0.05) and after albumin (Figure 5) and globulins (Figure 6) as they are tightly feeding (p<0.001) at a higher extent. The lower blood glucose levels related. The albumin to globulins ratio is also known as protein after feed supplementation with Protozin A were probably due to coefficient. It has an equal value of 0.29 in all collected samples – higher metabolic rate and glucose uptake in many metabolic regardless of the diet type and the sampling time (before or after pathways (glycolytic, pentose phosphate cycle etc.) to provide the feeding). body with energy and intermediate metabolites of vital importance. Blood serum albumin varied between 15.10 g/l and 15.83 g/l –

values much lower than the lower reference limit established at the Laboratory Diagnostic Centre at the Faculty of Veterinary Medicine – Trakia University (25–39 g/l), and Reference Values for Laboratory Animals - Research Animal Resources, University of Minnesota, or Normal Values-Sheep, Iowa State University (24–30 g/l). According to Caldeira et al. (2007) blood albumin and urea concentrations are the best markers of protein metabolism in ruminants.

The observed increase in blood albumin during the

Blood serum total protein in experimental animals ranged between 66.80 g/l and 71.00 g/l (Figure 4). The differences were insignificant, but a clear trend towards increase was outlined when animals were fed Paulownia leaves. Postprandial total protein concentrations decreased for both rations. The total serum protein includes all blood protein except those of blood cells and fibrinogen. Total protein is a sum of albumin and globulins, with reference values for sheep between 60–80 g/l. It is mainly influenced by dietary factors- type and structure of the ration, supplementation of exogenous enzymatic preparations without underestimating physiological factors as age, physiological condition etc. The tests of a ration similar to the baseline one in rams showed total blood

experimental period (when sheep were fed only Paulownia leaves), could be explained by the enhanced protein synthesis in growing animals, if not accompanied by increased globulins as well. The facts that albumin increase was insignificant and that globulin

Figure 3. Blood serum glucose concentrations

5.0

4.04.23

3.48

3.0

2.0

1.0

0.0Paulownia leavesControl ration

mm

ol/l

0 h 2.5 h

4.57

3.53

Figure 4. Blood serum total protein concentrations

67.90

66.80

71.00

64.0

71.0

70.0

69.0

68.0

67.0

66.0

65.0

Paulownia leavesControl ration

g/l

0 h 2.5 h

69.67

Figure 5. Blood serum albumin concentrations

15.20

14.6

16.0

15.8

15.6

15.4

15.2

15.0

14.8

Paulownia leavesControl ration

g/l

0 h 2.5 h

15.50

15.10

15.83

Figure 6. Blood serum globulins concentrations

52.7

49.0

56.0

55.0

54.0

53.0

52.0

51.0

50.0

Paulownia leavesControl ration

g/l

0 h 2.5 h

54.17

51.7

55.17

408

concentrations were within the reference limits are somewhat Bergman EN, 1971. Hyperketonemia-Ketogenesis and ketone reassuring. Nevertheless, the considerable effect of the dietary body metabolism. Journal of Dairy Science, 54, 936-948.source type was evident and we may only suggest as to whether the Bergman EN, 1973. Glucose metabolism in ruminants as related to effect of tannins or some not fully identified alkaloids in Paulownia hypoglycemia and ketosis. Cornell Veterinararian 63, 341-362.leaves was more pronounced. Boying W, 1995. Utilization of Paulownia foliage. In: Mantang C and

In previous studies of ours, a similar lack of change in blood Shaofang H (eds) Integrated Research in Farm Forestry, pp serum urea and globulins was established as well as increased 147–152. China Science and Technology Press Beijing, China.albumins after supplementation of Hostazym C100 to lamb rations, Caldiera RM, Belo CC, Santos CC, Vazques MI and Portugal AV, but it was interpreted as indicator of enhanced protein synthesis in 2007. The effect of body condition score on blood metabolites and growing animals as it was accompanied by reduction in serum hormonal profiles inewes. Small Ruminant Research, 68, 3, 242-globulins. There was neither a statistically significant effect of dietary 255.supplementation of Hostazym X100 in lambs fed concentrate, El-Showk S and El-Showk N, 2003. The Paulownia tree – An despite the observed tendency towards increased amount of both alternative for sustainable forestry. The farm.blood albumin and globulins. It was shown that Hostazym C100 Grigorova N, 2009. Effect of multienzymatic fibrolytic preparations provoked a highly significant increase in blood albumins (Todorova Hostazym C100 and Hostazym X 100 on ruminant digestion. Thesis et al., 2009; Grigorova et al., 2009). for PhD, 138 p.

To our best knowledge, the effect of exogenous enzymatic Grigorova N, Todorova P, Radev V and Sivkova K, 2009. Effect of preparations on blood albumin and globulins concentrations was not the multienzymatic preparation Hostazym C 100 on weight consistent. The addition of Hostazym X100 to three different rations development, forage utilization and some hematological for yearling sheep resulted in various extent of reduction (from characteristics in lambs. Proceedings IV Balkan Conference of insignificant to considerable at р<0.001) of blood albumin and Animal Science BALNIMALCON, pp 233-238.increase in globulins both before feeding and 2.5 h after feeding Hongfu Z, Peng R and Boying W, 1995 Evaluation of Paulownia (Grigorova, 2009). Hostazym C100 supplementation to rations had fallen leaves as a feedstuff for ruminant animal. In: Mantang C and less pronounced effect on blood protein fractions ratio. A statistically Shaofang H (eds) Integrated Research in Farm Forestry, pp significant reduction in albumin (р<0.05) and increased globulins 153–157. China Sci & Tech Press Beijing, China.(р<0.001) was demonstrated after feeding a diet containing barley, Hristov AN, McAllister TA and Cheng KJ, 2000. Intraruminal sunflower meal and meadow hay. A similar in vivo effect of fibrolytic supplementation with increasing levels of exogenous enzymes supplementation was reported by Sivkova (2007) in polysaccharide-degrading enzymes. Effects on nutrient digestion in experiments with ruminants. This allowed the author to assume that cattle fed a barley grain diet. Journal of Animal Science, 78, 477-487.enzymatic dietary supplements in ruminants played probably a role Huo Y, 1992 Taungya in China. In: Jordan CF, Gajaseni J and of immunobiological stimulators. Watanabe H (eds) Taungya: forest plantations with agriculture in

To sum up, it could be affirmed that the conclusions of many southeast Asia, pp 133–147. CAB Int, UKresearchers, both foreign (Kumar and Singh, 1984; Zhu et al., 1986; Koleva A, Dobreva K, Stoyanova M, Denev P, Damianova S, Mehansho et al., 1987; Zhaohua, 1987; Austin et al., 1989; Mueller Ilchev A, Tasheva S, Ganchev G, Pavlov D, Angelov B and et al., 2001; El-Showk and El-Showk, 2003), and Bulgarian (Koleva Stoyanova A, 2011a. Paulownia – a source of biologically active et al., 2011b) about the utilisation of Paulownia leaves as a feed substances. 1. Composition of leaves. Journal of Mountain source should be subject to a serious revision on the basis of Agriculture on the Balkans, 14, 5, 1061-1068.observed alterations in studied blood parameters. More evidence Koleva A, Dobreva K, Stoyanova M, Denev P, Damianova S, would be probably available from experimental data from different Ilchev A, Tasheva S, Ganchev G, Pavlov D, Angelov B and parameters related to the rumen and more distant compartments of Stoyanova A, 2011b. Paulownia – a source of biologically active the alimentary tract which are soon to be published. substances. 2. Amino acid composition of leaves. Journal of

Mountain Agriculture on the Balkans, 14, 5, 1078-1086.Kumar R and Singh M, 1984. Tannins, their adverse role in ruminant nutrition. Journal of Agricultural and Food Chemistry, 32, Conclusion447-453.Mehansho H, Butler L and Carlson DM,1987. Dietary tannins and The intake of Paulownia leaves resulted in statistically salivary proline-rich proteins: interactions, induction and defense significant reduction in erythrocyte (p<0.05) and leukocyte counts mechanisms. Annual Review of Nutrition, 7, 423-440.(p<0.001). This was most pronounced in the postprandial hours. A Mueller JP, Luginbuhl JM and Bergmann BA, 2001. statistically significant (p<0.001) reduction in blood glucose Establishment and early growth characteristics of six Paulownia concentrations was demonstrated.genotypes for goat browse in Raleigh, NC, USA. Agroforestry Paulownia leaves also provoked increased total serum protein Systems, vol. 52, 63–72, 2001. Kluwer Academic Publishers. concentrations on the account of both higher albumin and globulins. Printed in the Netherlands.The albumin/globulin ratio was 0.29 regardless of the type of diet or Murgov I, Ploshtakova M and Denkova Z, 1995. Aminoacods. the time of sampling – prior to or after feeding.Sofia. IK Agropress.Nedeva N, Sivkova K, Radev V, Tsankova M and Slavov T, 2008. Effect of multienzyme preparation Hostazym С 100 in buffalo calves

References fed rations with different dietary concentrate/roughage ratios. I. Effect of Hostazym С 100 on hydrogen ions, ammonia

Austin PJ, Suchar LA, Robbins CT and Hagerman AE, 1989. concentrations and volatile fatty acids molar ratio. Animal Science, Tannin-binding proteins in saliva of deer and their absence in saliva Sofia, 5, 100-107.of sheep and cattle. Journal of Chemical Ecology, 15, 1335-1347. Radev V, Sivkova К, Еnev Е, Nedeva N and Slavov Т, 2009. Effect

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of the multienzyme preparation Hostazym C 100 upon the digestion digestion, metabolism and productivity of small ruminants, Thesis and feeding behaviour of buffalo calves, fed on diets with different for PhD, Trakia University (Bg).concentrate and roughage proportions. IV. Effect on some Todorova P, Grigorova N, Radev V and Sivkova K, 2009. Effect of haematological parameters Bulgarian Journal of veterinary the multienzymatic preparation Hostazym Х 100 on the weight Medicine, 12, suppl 1, 124-129. development, forage utilization and some hematological

thSeal CJ and Reynolds CK, 1993. Nutration implications of characteristics in lambs. Proceedings of the 4 International gastrointestinal and liver metabolism in ruminants. Nutration Scientific Conference Balnimalcon - 2009. Animal higher education Reasearch Reviews 6, 185-208. of Bulgaria, problems and Perspectives. Challenges of the Balkan Sivkova K, 2007. Digestion process by the ruminants in the animal industry and the role of science and cooperation, 14-16 may, dependence of diet composition and structure. Thesis for DSc, Stara Zagora, 228-232.Trakia University, Agricultural Faculty, Stara Zagora, pp. 280 Zhaohua E, 1987. A new farming system. Crop/Paulownia Sivkova K, Radev V, Todorova P, Todorov M and Enev E, 2004. intercropping. Multipurpose tree species from small-farm use. Effect of the multienzyme Protozyn-A on the level of some Proceedings of an international workshop held in November 2-5, hematological parameters of sheep. Trakia Journal of Sciences, 2, 2 Pattaya, Thailand, 65-69.SeriesBiomedical Scienses pp 31-34. Zhu ZH, Chao CJ, Lu XY and Xiong YG (1986) Paulownia in China: Sivkova К, Radev V, Iliev Y, Penchev I and Dimitrova S, 2006. cultivation and utilization. Asian Network for International Effect of enzyme preparation Xybeten – Cel on some Development Research Centre, Canada, 65 pp72.haematological and blood protein metabolism parameters. Scientific http://www.cropdevelopment.org/paulownia/Brochure.pdf.Session of the Trakia University, Animal Sciences, 1, pp. 33-39 http://www.lar.iastate.edu/Slavov Т, 2013. Effect of dietary lipids supplementation on http://www.ahc.umn.edu/rar/refvalues.html

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Use of recurrent selection in middle late synthetic maize populationI. Results of the first cycle in synthetic “1/2005”N. Petrovska, V. Valkova

Genetic diversity and distance between two Bulgarian local sheep breeds assessed by microsatellite markersS. Georgieva, E. Todorovska, D. Hristova, I. Dimitrova, N. Stancheva, Ts. Yablanski

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Evaluation of double haploid lines of winter malting barley using selection indicesB. Dyulgerova, D. Valcheva

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Instruction for authors

Preparation of papersPapers shall be submitted at the editorial office typed on standard typing pages (A4, 30 lines per page, 62 characters per line). The editors recommend up to 15 pages for full research paper ( including abstract references, tables, figures and other appendices)The manuscript should be structured as follows: Title, Names of authors and affiliation address, Abstract, List of keywords, Introduction, Material and methods,Results, Discussion, Conclusion, Acknowledgements (if any), References, Tables, Figures.The title needs to be as concise and informative about the nature of research. It should be written with small letter /bold, 14/ without any abbreviations. Names and affiliation of authorsThe names of the authors should be presented from the initials of first names followed by the family names. The complete address and name of the institution should be stated next. The affiliation of authors are designated by different signs. For the author who is going to be corresponding by the editorial board and readers, an E-mail address and telephone number should be presented as footnote on the first page. Corresponding author is indicated with *.Abstract should be not more than 350 words. It should be clearly stated what new findings have been made in the course of research. Abbreviations and references to authors are inadmissible in the summary. It should be understandable without having read the paper and should be in one paragraph. Keywords: Up to maximum of 5 keywords should be selected not repeating the title but giving the essence of study. The introduction must answer the following questions: What is known and what is new on the studied issue? What necessitated the research problem, described in the paper? What is your hypothesis and goal ?Material and methods: The objects of research, organization of experiments, chemical analyses, statistical and other methods and conditions applied for the experiments should be described in detail. A criterion of sufficient information is to be possible for others to repeat the experi-ment in order to verify results.Results are presented in understandable

tables and figures, accompanied by the statistical parameters needed for the evaluation. Data from tables and figures should not be repeated in the text.Tables should be as simple and as few as possible. Each table should have its own explanatory title and to be typed on a separate page. They should be outside the main body of the text and an indication should be given where it should be inserted.Figures should be sharp with good contrast and rendition. Graphic materials should be preferred. Photographs to be appropriate for printing. Illustrations are supplied in colour as an exception after special agreement with the editorial board and possible payment of extra costs. The figures are to be each in a single file and their location should be given within the text. Discussion: The objective of this section is to indicate the scientific significance of the study. By comparing the results and conclusions of other scientists the contribution of the study for expanding or modifying existing knowledge is pointed out clearly and convincingly to the reader.Conclusion: The most important conse- quences for the science and practice resulting from the conducted research should be summarized in a few sentences. The conclusions shouldn't be numbered and no new paragraphs be used. Contributions are the core of conclusions. References:In the text, references should be cited as follows: single author: Sandberg (2002); two authors: Andersson and Georges (2004); more than two authors: Andersson et al.(2003). When several references are cited simultaneously, they should be ranked by chronological order e.g.: (Sandberg, 2002; Andersson et al., 2003; Andersson and Georges, 2004).References are arranged alphabetically by the name of the first author. If an author is cited more than once, first his individual publications are given ranked by year, then come publications with one co-author, two co-authors, etc. The names of authors, article and journal titles in the Cyrillic or alphabet different from Latin, should be transliterated into Latin and article titles should be translated into English. The original language of articles and books translated into English is indicated in parenthesis after the bibliographic reference (Bulgarian = Bg, Russian = Ru, Serbian = Sr, if in the Cyrillic, Mongolian =

Мо, Greek = Gr, Georgian = Geor., Japanese = Jа, Chinese = Ch, Arabic = Аr, etc.)The following order in the reference list is recommended:Journal articles: Author(s) surname and initials, year. Title. Full title of the journal, volume, pages. Example:Simm G, Lewis RM, Grundy B and Dingwall WS, 2002. Responses to selection for lean growth in sheep. Animal Science, 74, 39-50Books: Author(s) surname and initials, year. Title. Edition, name of publisher, place of publication. Example: Oldenbroek JK, 1999. Genebanks and the conservation of farm animal genetic resources, Second edition. DLO Institute for Animal Science and Heal th, Netherlands.Book chapter or conference proceedings: Author(s) surname and initials, year. Title. In: Title of the book or of the proceedings followed by the editor(s), volume, pages. Name of publisher, place of publication. Example: Mauff G, Pulverer G, Operkuch W, Hummel K and Hidden C, 1995. C3-variants and diverse phenotypes of unconverted and converted C3. In: Provides of the Biological Fluids (ed. H. Peters), vol. 22, 143-165, Pergamon Press. Oxford, UK.Todorov N and Mitev J, 1995. Effect of level of feeding during dry period, and body condition score on reproductive perfor-

thmance in dairy cows,IX International Conference on Production Diseases in Farm Animals, Sept.11 – 14, Berlin, Germany, p. 302 (Abstr.).Thesis:Penkov D, 2008. Estimation of metabolic energy and true digestibility of amino acids of some feeds in experiments with muscus duck (Carina moshata, L). Thesis for DSc. Agrarian University, Plovdiv, 314 pp.

The Editorial Board of the Journal is not responsible for incorrect quotes of reference sources and the relevant violations of copyrights.EthicsStudies performed on experimental animals should be carried out according to internationally recognized guidelines for animal welfare. That should be clearly described in the respective section “Material and methods”.

Volume 5, Number 4December 2013