Estimation of differences in trace element composition of Bulgarian summer fruits using ICP-MS

G. Toncheva1, K. Nikolova2, D. Georgieva3, G. Antova4, V. Kuneva5

1Department of General and Inorganic Chemistry with Methodology of Chemistry Education, Faculty of Chemistry University of Plovdiv Paisii Hilendarski,
4000 Plovdiv, Bulgaria
2Department of Mathematics and Physics, Faculty of Economics University of Food Technologies, 4000 Plovdiv, Bulgaria
3Department of Analytical Chemistry and Computer Chemistry, Faculty of Chemistry, University of Plovdiv Paissii Hilendarski, 4000 Plovdiv, Bulgaria
4Department of Chemical Technology, Faculty of Chemistry, University of Plovdiv Paissii Hilendarski, 4000 Plovdiv, Bulgaria
5Department of Mathematics, Physics and Informatics, Faculty of Economics, Agricultural University, 4000 Plovdiv, Bulgaria
(Manuscript received 14 May 2016; accepted for publication 20 June 2016)

Abstract. The content of potentially essential and toxic elements: chromium, manganese, iron, copper, nickel, cadmium and arsenic in Bulgarian fruits such as aronia, morello, cherry, raspberry, nectarine peach, apple type „akane” and pear type „early gold” were investigated. By using the ICP-MS we found that raspberry has the highest content of iron (4635.9 ± 53.2 μg kg-1), manganese (5690.9 ± 31.7 μg kg-1) and chromium (150.2 ± 2.5 μg kg-1), while the richest in copper is the nectarine (887.5 ± 31.19 μg kg-1). The content of toxic elements (nickel, cadmium and arsenic) is in amount significantly below the permissible standards. Single ANOVA and subsequent Dunkan’s test were used to define the fruit and to estimate the significance of chemical elements. The test for multidirectional comparisons indicated that for five of the investigated seven elements: iron, copper, nickel, cadmium, and arsenic the fruits are statistically distinguishable. According to hierarchical cluster analysis the fruits are into one cluster.



Composition of meat in La Belle and White Plymouth Rock chickens, slaughtered at different age

Т. Popova*, E. Petkov, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria
(Manuscript received 16 May 2015; accepted for publication 8 June 2016)

Abstract. An experiment with two lines of chickens – synthetic line La Belle and White Plymouth Rock was carried out in the Institute of Animal Science, Kostinbrod to assess the meat quality in regards to chemical composition and the fatty acid profile at the age of 9 and 18 weeks. The age affected the lipid content which decreased significantly in breast (p<0.05) and thighs (p<0.01) in the older chickens of both lines. The content of protein and moisture in breast differed between the lines (p<0.05), showing higher protein and lower moisture in White Plymouth Rock chickens, while in the thigh muscles the line and age significantly interacted (P<0.001) in regards to these traits. Interactions between the two factors (p<0.01) was observed for the ash content in the breast, whereas in the thighs it tended to decrease with the age in both lines. The fatty acid composition of the meat was influenced mainly by the age of the chickens. The total content of the saturated fatty acids was increased in the thighs of the older birds (p<0.01), while the proportion of the monounsaturated fatty acids was decreased in the breast (p<0.01) and thighs (p<0.001) with advancing age of the chickens. The opposite was observed for the content of the polyunsaturated fatty acids in the breast, which increased at higher age of slaughter (p<0.001). In thigh meat, the changes of the polyunsaturated fatty acids induced by age followed the same pattern, however significant interaction with the line was observed (p<0.05). The cholesterol content in the breast differed significantly between the two lines (p<0.05) and reduced with age (p<0.001). In the thighs considerable decrease (p<0.001) of the cholesterol was observed in La Belle birds.


Stone marten (Martes foina, Erxl., 1777) and villagers: human-wildlife social conflict

S. Peeva* , E. Raichev

Department of Animal Production, Monogastric and Other Animals, Faculty of Agriculture, Trakia University 6000 Stara Zagora, Bulgaria
(Manuscript received 16 May 2016; accepted for publication 8 June 2016)

Abstract. The “Human-wildlife conflict” refers to the interaction between wild animals and humans and the negative impact on their resources or wildlife and their habitats. One of the reasons for its occurrence is the entry of wild animals in urban environment. Stone marten often enters into settlements and its activity provokes conflict with humans. To clarify the attitude towards coexistence with this species a survey among 132 residents of villages in the region of Sarnena Sredna Gora Mountain was conducted in the period 01.12.2015-31.03.2016. The opinion of people familiar with stone marten’s biology (hunters) and other people (retired and active) was explored. The differences between men and women were examined. In settlements stone marten is considered to be a pest, attacking smaller livestock. Its presence disturbs humans by- displacing tiles on the roofs, noise, faeces etc., and consequently Human-wildlife conflict emerges. More than half of people are not convinced to take ultimate measures against martens. Human-stone marten conflict in Bulgarian villages is still at the tolerance level.


Investigation of the biota of Burgas Bay, Black Sea

D. Klisarova*, E. Petrova, D. Gerdzhikov, S. Stoykov

Institute of Fish Resources, 4 Primorski, 9000 Varna, Bulgaria
(Manuscript received 23 March 2016; accepted for publication 30 May 2016)

Abstract. Burgas Bay is the largest one on the Bulgarian Black Sea coast. Industrial plants along the coast as well as ports for liquid and solid cargoes create conditions of anthropogenic pressure on hydrobionts in that area. Macrozoobenthos and phytoplankton samples were collected under a specific scheme in connection with the construction of the Burgas-Alexandroupolis oil pipeline, at stations located around the designated places for unloading tankers. During the study period (2009 – 2010), 88 phytoplankton species distributed in 13 classes were identified and over 50 species of benthic species distributed in four main groups: Polychaeta, Mollusca, Crustacea and the mixed group Diversa.


Indicator polychlorinated biphenyl residues in muscle tissue of fish from Black Sea coast of Bulgaria

S. Georgieva*, M. Stancheva

Department of Chemistry, Medical University, Marin Drinov 55, 9002 Varna, Bulgaria
(Manuscript received 25 April 2016; accepted for publication 30 May 2016)

Abstract. Polychlorinated biphenyls (PCBs) are characterized by high lipophilicity and persistence in the environment and will therefore bioaccumulate and biomagnify in the food chain. PCBs were determined in muscle tissue of four fish species: goby (Neogobius melanostomus), horse mackerel (Trachurus Mediterraneus ponticus), shad (Alosa pontica pontica) and turbot (Psetta maxima maeotica). Samples were collected from Bulgarian Black Sea coast during 2007- 2011. The PCBs were analyzed in order to examine the time trends of PCB concentrations in fish from Black Sea. The six individual PCBs congeners were determined by capillary gas chromatography system with mass spectrometry detection. PCBs were found in all fish species at concentrations ranging between 2.32 ng/g ww (wet weight) and 32.87 ng/g ww in goby and shad, respectively. PCB profiles have been found to be similar in all the fish species tested. The most abundant PCB congeners in fish species were hexa- and heptachlorinated PCBs 138, 153 and 180. PCB 153 was the dominant congener in all fish studied and were found in the range from 0.95 ng/g ww (horse mackerel 2011) to 11.67 ng/g ww (shad 2010). The sum of six indicator PCBs in all fish species did not exceed the European maximum limit of 75 ng/g ww. The levels of PCBs in fish from Bulgarian Black Sea coast were found lower than in fish species from other seas – the Aegean Sea and the Mediterranean Sea.


Application of up-to-date environmental indices for assessment of seawater

D. Klisarova*, D. Gerdzhikov, E. Petrova

Institute of Fish Resources, 4 Primorski, 9000 Varna, Bulgaria
(Manuscript received 23 March 2016; accepted for publication 26 May 2016)

Abstract. The paper discusses the indices for assessment of the ecological status of seawater which are applied in the studies of algae and macrozoobenthic communities in the Bulgarian Black Sea territorial waters. They are applicable to contemporary environmental assessments in accordance with the European directives on environmental protection. Presented are also studies carried out in recent years on marine plants and bottom organisms and the resulting conclusions. The result was that we identified the ecological status of the marine ecosystem on BQE phytoplankton, macrophytobenthos and macrozoobentos from “moderate” to “good” in the period of investigation.


Productivity and quality of open field tomato after application of bio-fertilizers

H. Botеva*

Vegetable Crops Research Institute Maritsa, 32 Bezovsko shoose, 4003 Plovdiv, Bulgaria
(Manuscript received 27 April 2016; accepted for publication 31 May 2016)

Abstract. Field experiments for the effect of bio-fertilizers: Labin, Bio One, Tecamin, Agriful, Humustim and Biohumus on productivity and fruit quality of determinant tomato, variety Trapezitsa were performed on strongly leached meadow cinnamonic soil at the experimental field of the Vegetable Crops Research Institute Maritsa during the period 2008 – 2010. The fruit number per tomato plant increased up to 38.2% towards the control (without fertilization) by using bio-fertilizers Tecamin and Agriful. Similar were the results for the mass of fruits per plant, where the increase was up to 33.3% towards the control. After mineral fertilization the total tomato yield is the highest on average for the period of study. An increase of the yield in tomato with reduced mineral fertilization is established after application of bio-fertilizers 12.1% on average from 7.8% /after fertilization with Labin/ to 18.3% /after fertilization with Tecamin/ towards the control. A positive effect by fertilization with Tecamin (38.8%) and Agriful (36.3%) is established on early production. In mineral fertilization this index is lower (23.7%). Bio-fertilizers Tecamin and Agriful have a positive effect on the content of vitamin C and dry matter.


Performance of eleven plum cultivars under agroclimatic conditions of Plovdiv region, Bulgaria

V. Bozhkova*, P. Savov

Fruit Growing Institute, 4004 Plovdiv, Bulgaria
(Manuscript received 13 May 2016; accepted for publication 8 June 2016)

Abstract. Plum is a traditional fruit crop in Bulgaria. The South Central Region represents 22.2% of the total area occupied with plum trees. In this study the results of a four years’ investigation on ten plum cultivars carried out at the Fruit Growing Institute in Plovdiv are presented. Stanley was used as a standard. The observed phenological characteristics included flowering and fruit ripening. The cultivars Tophit plus and Toptaste are the earliest flowering, whereas Topstar plus is the latest one. Fruits of Topfirst cultivar ripen at the beginning of July, those of Top and Tophit plus in September and all the rest in August. According to biometrical analyses, fruit weight of Topgigant plus and Tophit plus is over 60g. The total soluble solid content in the studied cultivars varies from 15.7% in Top cultivar to 24.75% in Toptaste. Yield was determined and expressed in kg per tree. Over 30 kg per tree was harvested from the cultivars Stanley, Jojo, Topgigant plus and Tophit plus. The lowest yield was obtained from the cultivars Top, Topfive and Toptaste. In 2012, the percentage of flower buds destroyed by frost was evaluated. The lowest degree of damages was reported in the cultivars Tophit plus, Topgigant plus and Mirabelle de Nancy (below 10%), and the greatest damages in Toptaste (51%). According to the obtained results, the most suitable plum cultivars recommended to be grown in Plovdiv region, are Jojo, Topgigant plus and Tophit plus, as well as the cultivar Bellamira from the group of Mirabelle plum.


Effect of cocoon fluorescence, silkworm hybrid and gender on sericin content of Bombyx mori L. silk thread

M. Panayotov*

Department of Animal Science – Non-ruminants and other animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 11 April 2016; accepted for publication 26 May 2016)

Abstract. The goal of the present study was to determine the influence of the ultraviolet fluorescence of cocoons, the hybrid, the sex and the interaction among them on the sericin content in silk threads. The study was performed with 3 di- and 2 tetra-cross silkmoth (Bombyx mori L.) hybrids, differentiated in three groups – with violet, intermediate and yellow fluorescence of the cocoons. The examined factors had a significant effect (p≤0.001) on the sericin content. The highest sericin content was detected in the silk threads of the violet-fluorescent and the lowest – in the yellow-fluorescent group. The analysed di-hybrids were distinguished by better characteristics in terms of sericin content, compared to the tetra-hybrids, most obvious for the yellow-fluorescent fraction.


Selectivity and stability of new herbicides and herbicide combinations for the seed yields of some field crops

G. Delchev*

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 28 January 2016; accepted for publication 30 May 2016)

Abstract. During 2013 – 2015 on pellic vertisol soil type was conducted a field experiment. Under investigation was Bulgarian milk thistle cultivar Silmar (Silybum marianum Gaertn.). Factor A included the years of investigation. Factor B included no treated check, 6 soil-applied herbicides – Tendar EC, Sharpen 33 EC, Merlin flex 480 SC, Smerch 24 ЕC, Raft 400 SC, Eagle 75 DF and 5 foliar-applied herbicides – Kalin flo, Eclipse 70 DWG, Sultan 500 SC, Granstar super 50 SG, Starane 250 EK. Factor C included no treated check and 1 antigraminaceous herbicide – Tiger platinium 5 EC. All herbicides, herbicide combinations and herbicide tank-mixtures were applied in a working solution of 200 l/ha. Mixing of foliar-applied herbicides was done in the tank on the sprayer. Soil-applied herbicides were treated during the period after sowing before emergence. Foliar-applied herbicides were treated during rosette stage of the milk thistle. Tank mixtures of antigraminaceous herbicide Tiger platinum with foliar herbicides Kalin flo, Eclipse, Sultan, Granstar super and Starane leads to obtaining high seed yields of milk thistle. High yields seeds are also obtained by foliar treatment with Tiger platinum after soil-applied herbicides Raft, Sharpen and Eagle. The use of the soil-applied herbicides Smerch, Merlin flex and Tendar does not increase the seed yield due to its higher phytotoxicity against milk thistle. Herbicide Tendar and herbicide combination Tendar + Tiger platinum are the most unstable, followed by herbicide Merlin flex. Herbicide tank-mixtures Kalin flo + Tiger platinum and Eclipse + Tiger platinum and herbicide combination Raft + Tiger platinum are technologically the most valuable. They combine high seed yield with high stability with relation to different years. Single application of soil-applied or foliar-applied herbicides have low estimate; due to that they must be combined for full control of weeds in milk thistle crops.