Lysozyme levels in haemolymph of worker bees (Apis mellifera L.) from bee colonies with different degree of expression of hygienic behaviour

S. Lazarov1, I. Zhelyazkova1*, D. Salkova2, R. Shumkova3, S. Takova4

1Department of Animal Science-Non-ruminants and other Animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Bulgarian Academy of Sciences, Institute of Experimental Pathology and Parasitology, Fauna and circulation of parasites, 1000 Sofia, Bulgaria 3Experimental Station in Animal Husbandry and Farming, 4700 Smolyan, Bulgaria
4National Diagnostic Scientific Research Veterinary Medical Institute, 1000 Sofia, Bulgaria

(Manuscript received 1 June 2016; accepted for publication 10 August 2016)

Abstract. A total of 24 bee colonies of apiaries with different business orientation were tested for the degree of expression of hygienic behaviour by modified method, different from the traditionally used for this purpose method. To outline the test field a square sized 5 x 5 cm was used, stuck onto a section of a honey comb with sealed worker brood (the area bounded by the stencil is equal to 100 worker bee cells). The brood in the outlined square is killed by a thin entomological needle by jabbing the sealed cells, without destroying their caps. Depending on the time and extent of cleaning bee colonies are divided into 3 groups: super hygienic – colonies which of the 24th hour after the jabbing have uncovered and cleaned over 95% of the outlined area; hygienic – colonies which on the 48th hour after the jabbing have uncovered and cleaned over 95% of the outlined area; non- hygienic – colonies which have cleaned less than 95% of the cells in the area on the 48th hour. From each bee colony samples of worker bees (200-250 pcs.) have been taken and haemolymph obtained. The amount of lysozyme has been defined at the Reference Laboratory “Honeybee health” at the National Diagnostic Scientific Research Veterinary Medical Institute – Sofia by the method of Motavkina et al. (1979), modified by Kostov et al. (1983). The results obtained show different values for the amount of lysozyme in haemolymph of worker bees, depending on the degree of expression of their hygienic behaviour – 10.49 ± 1.86 μg/ml for the group of super hygienic colonies; 9.11 ± 1.37 μg/ml for the group of hygienic ones; 15.22 ± 2.37 μg/ml for the group of non-hygienic bee colonies, respectively. The established values range from 4.59 μg/ml to 38.28 μg/ml, the greatest variation being in the group of non-hygienic colonies. The data suggests that in positive direction compared to the average for the model is the deviation of LS-means of bee colonies with low level of hygiene (non-hygienic). The reported LS-estimates suggest that in the non- hygienic bee colonies there is a tendency of increase the lysozyme content in the haemolymph.


Plastid pigments quantity and some physiological parameters related to photosyntetic processes in triticale grown for green biomass

H. Nedeva*, R. Ivanova, H. Yancheva

Crop Science Department, Faculty of Agronomy, Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria
(Manuscript received 20 May 2016; accepted for publication 6 June 2016)

Abstract. The aim of the study was to establish the amount of plastid pigments and some physiological parameters related to photosynthetic processes in two triticale cultivars, grown for biomass under different nitrogen fertilization rates and harvesting stages in the region of Southern Bulgaria. The research was carried out in the field of Crop Science Department at the Agricultural University, Plovdiv, during the period 2013 – 2015. The experiment was set after the block method with four replications, and 20m2 for each experimental plot. Two triticale cultivars – Musala and Attila grown for green biomass at different fertilizer rates (N , N , N , N , N ) have been tested. The two cultivars are harvested in heading formation and milk maturity stages. The physiological parameters – 0 120 160 200 240 intensity of transpiration, photosynthesis rate and the amount of plastid pigments (Chlorophyll A, Chlorophyll B, Carotene) have been observed at different cultivars and harvesting stages. In both tested cultivars in heading stage the transpiration intensity was higher when rates of N were used, while in milk 200 maturity stage the highest values were in variant with N . The photosynthesis rate at both cultivars in heading stage was increased with increase of the 240 nitrogen rate. In the stage of milk maturity the values of some indices decreased in both cultivars. The lowest content of plastid pigments in leaves of Musala cultivar was received in the control variant. It was observed that the increase of the nitrogen rate leads to increasing the pigments content. The highest content of pigments in Attila cultivar was received when N was applied.

Optimization of formulations with balanced biochemical composition and possibilities for their extrusion

M. Ruskova1*, T. Petrova1, I. Bakalov1, N. Penov2, A. Simitchiev2

1Food Research and Development Institute, 154 V. Aprilov, 4000 Plovdiv, Bulgaria
2Department of Canning and Refrigeration Technology, Technological Faculty, University of Food Technologies, 26 Maritza, 4000 Plovdiv, Bulgaria
(Manuscript received 10 June 2015; accepted for publication 9 May 2016)

Abstract. Combinations of different raw materials (beans, einkorn wheat, and buckwheat) for obtaining formulations with high protein content and balanced amino acid composition were studied using simplex centroid design. The target functions for optimization were content of protein, sulfur-containing amino acid methionine and cysteine, lysine, and tryptophan. The optimal area of combinations of raw materials in the food formulas with balanced biochemical composition was obtained. Optimized ternary mixture consisting of 50% bean, 40% einkorn wheat, and 10% buckwheat with different moisture content (16, 22, and 28%) has been extruded in a laboratory single screw extruder (Brabender 20 DN, Germany). Extrusion parameters were as follows: feed screw speed 50 rpm, die diameter 3 mm, screw compression ratio 2:1, temperature profile 100/140/160ºC, screw speed 160 rpm. The three extrudates with different initial moisture were evaluated by sectional expansion index, water absorption index, water solubility index, and density, with the aim of choosing the best treatment. The results demonstrated that the 22% initial moisture content yielded an extrudate with good physicochemical characteristics overall but an optimization study is needed to confirm this.

Influence of mineral nitrogen and organic fertilization on the productivity of grain sorghum

S. Enchev*, G. Kikindonov

Agricultural Institute, 9700 Shumen, Bulgaria

Abstract. The production of grain sorghum has increased in recent years. The modern varieties are hybrids with high productivity potential appropriate for application of intensive forage grain production technologies. The increased requirements for ecological production necessitate optimization of the nutrition parameters in the conditions of unstable agriculture with unbalanced soil nutrient substance accumulation. The effect of nutrition with mineral nitrogen fertilizer and organic fertilizer Humustim on the productivity of 6 varieties of Euralis Semences, popular in the practice, was tested during 2011 – 2013. In the various climatic conditions fertilization is a highly effective factor for productivity increase. The use of organic fertilizers such as Humustim widens the possibilities of the ecological production.


Energy productivity, fertilization rate and profitability of wheat production after various predecessors I.Energyproductivityofwheat

Z. Uhr1*, E. Vasileva2

1Institute of Plant Genetic Resources, 2 Druzhba, 4122 Sadovo, Bulgaria
2University of Agribusiness and Rural Development, 78 Dunav, 4000 Plovdiv, Bulgaria

Abstract. As a consequence of a long-year comparative study of quality, productivity and physiological characteristics of Bulgarian varieties of common winter wheat(Triticumaestivum),wecarriedouta studyontheadaptationofmoderngenotypestotherequirementsofsustainableagricultureandrespectivelytheir effectiveness of breeding methods with respect to these requirements. In the course of this study were also accumulated additional data concerning the influence of the predecessor and nitrogen fertilizer rate on energy productivity of crop, energy and recyclable efficiency of fertilization and profitability of production. In two consecutive publications we summarize and share with the scientific community the data that we have received. The results are up-to-date and useful in both theoretical and practical aspects. The analysis is based on data from field fertilizer experiments carried out with predecessor cereal – regular crop of sorghum, millet, maize and legumes after predecessor–separate sowing of chickpeas. Energy productivity is calculated as a function of yield (grain, straw and total biological yield, (t/ha), multiplied by the energy equivalent unit (MJ/kg). Maximum values of gross energy productivity by grain yields are reported by fertilization rate with 0.18 t/ha nitrogen fertilizer after cereal predecessor and after 0.06 t/ha after legumes. After cereal predecessor the effect of increasing the fertilizer rate to 0.18 t/ha N improves energy productivity of grain by 160% compared to the control N0. After legumes predecessor at N 0.0 t/ha energy productivity with grain was 12%, and in N 0.06 – 21% higher than the maximum (at 0.18 t/ha) after cereal predecessor. Legume predecessor unifies differences between genotypes and fertilizer levels on energy productivity of grain and increases energy productivity of straw by 16% on average. Maximum values of gross energy productivity of straw are reported in fertilization with 0.12 t/ha after wheat and 0.24 t/ha fertilizer nitrogen after legume predecessor. Increasing the fertilizer rate from 0.0 t/ha to 0.18 t/ha nitrogen reduces the difference in the gross energy productivity of crops after legumes and cereal predecessor from 105% in 0.0 t/ha to 10% in 0.18 t/ha. The differences between both varieties regarding the studied parameters are statistically significant at P < 0.001.


Phosphorus fractions in alluvial meadow soil after long-term organic-mineral fertilization

S. Todorova*, K. Trendafilov, M. Almaliev

Department of Agro-chemistry and Soil Science, Faculty of Agronomy, Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria

Abstract. The aim of our study was to investigate phosphorus fractions, their content and distribution in alluvial meadow soil after continuous fertilization. Our research was focused on a long-term field experiment with different variants of fertilization set in 1959 in the Experimental field of Agricultural University of Plovdiv. Since 2006 the fertilization has been discontinued. In 2011, we collected soil samples from two depths (0 – 30 and 30 – 40 cm) and from the following variants: variant 1 (control, without fertilization), variant 2 (N50P30K20), variant 3 (N25P15K0 + 6t/da manure), variant 4 (N50P0K20). The studied soil is characterized by relatively good natural phosphate regime. The amount of available phosphates determined by the Egner-Rheem method is high – average 16.76% of the total phosphorus. Over 50% of the mineral phosphates in the soil are in available (in varying degree) form. Relatively high is the amount of organic phosphates, which during the mineralization can also be involved in the plant nutrition. The amount of available phosphates (according to Egner-Rheem) is determined to the highest degree by the total phosphorus in soil, which in turn is highly correlated with the content of hardly soluble calcium phosphates.


Ethological and haematological indices in yearling sheep fed various dietary nitrogen sources

I. Varlyakov*, V. Radev, Т. Slavov, R. Mihaylov

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

Abstract. A physiology experiment was conducted to evaluate the effects of diet supplementation with non-protein nitrogen compounds Optigen and urea. The trialcomprisedthreeperiods:control–yearlingsheepwerefed rationwithbarley,sunflowermealandmeadowhay;firstexperimental–thesamerationwas supplemented with 12 g Optigen and second experimental – the ration was supplemented with 10.6 g urea. The addition of Optigen resulted in increased appetite and faster consumption of the food as seen from lower feeding time and increased rumination time. The welfare of animals was good as seen from the low ratio of time spent ruminating in standing position to total rumination time and the dominating values of rumination and rest times without statistically significantdifferencesbetweenexperimentalperiods.Therewerenodifferencesbetweentimesspentstandingand loafing,includingmovementinsidethe box, which is an indirect index for lack of discomfort and reliable testimony for the conditions of the present experiments. The blood picture results allowed affirming that the health status of experimental animals was within the reference limits. Proofs in support of this thesis were the fact that lower red blood cell counts were compensated by the higher haemoglobin content, whereas white blood cell counts were normal and accompanied by nutritional leukocytosis during all three study periods.


Histopathological pancreatic changes in broiler chickens with experimental aflatoxicosis

I. Valchev1*, N. Grozeva2, D. Kanakov1, Y. Nikolov1

1Department of Internal Non-infectious Diseases, Faculty of Veterinary Medicine, Trakia University, 6000, Stara Zagora, Bulgaria 2Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, 6000, Stara Zagora, Bulgaria

Abstract. Morphological changes in the pancreas of broiler chickens were followed out after experimental aflatoxicosis В1. Also, the possibility to prevent the deleterious effects of AFB1, through dietary supplementation of Mycotоx NG (Ceva Sante Animale, France) was evaluated. The 42-day experiments were carried out with 50 Cobb broiler chickens, divided in 5 groups of 10 chickens: Group I – control; Group II – supplemented with 1 g/kg Mycotox NG; Group III – supplemented with 0.5 mg/kg aflatoxin B1; Group IV –supplemented with 0.8 mg/kg aflatoxin B1; Group V –supplemented with 0.5 mg/kg aflatoxin B1 and 1 g/kg Mycotox NG. Gross pancreatic changes in broilers treated at 0.5 mg/kg AFB1 comprised generalised vascular hyperaemia, interlobular oedema, initial disintegration of glandular acini. Birds treated at 0.8 mg/kg AFB1 exhibited complete glandular acini disorganisation, and mononuclear cell infiltrations. The supplementation with Mycotox NG alleviated the frequencty and severity of observed histological lesions: slight interlobular oedema, generalised hyperaemia and early granular dystrophy of the cytoplasm of Langerhans islet cells.


Histopathological changes in small intestines of broiler chickens with experimental aflatoxicosis

N. Grozeva1*, I. Valchev2, Ts. Hristov2, L. Lazarov2, Y. Nikolov2

1Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Internal Non-infectious Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. Aflatoxins are toxic metabolites produced by moulds of Aspergillus genus (the most relevant producers are Aspergillus flavus and Aspergillus parasiticus). The primary aim of the current research is to follow out the toxic effects of aflatoxin В1 on the morphology of small intestine, which is important for digestion and absorption of feeds and at the same time, to investigate the possibility for prevention of toxic AFB1 effects by addition of the mycosorbent Mycotоx NG (Ceva Sante Animale, France) to the feed. The experiments were carried out with 50 Cobb broiler chickens, divided in 5 groups of 10 chickens (5 male : 5 female in the groups): Group I – control (receiving feed according to species and age); Group II – supplemented with 1 g/kg Mycotox NG; Group III – supplemented with 0.5 mg/kg aflatoxin B1; Group IV – supplemented with 0.8 mg/kg aflatoxin B1; Group V – supplemented with 0.5 mg/kg aflatoxin B1 and 1 g/kg Mycotox NG. The experiment’s duration was 42 days. After conventional histological technics the light microscopical analyze determined that the morphological changes in all small intestine (duodenum, jejunum, ileum) in birds treated at 0.5 mg/kg AFB1 consisted in vascular hyperaemia, single haemorrhagies, partial desquamation of villous epithelium, rarefaction of cells in intestinal lymphatic follicles and in some areas, cup cell hypertrophy and weak distrophy of Lieberkühn glands. Chickens treated with 0.8 mg/kg AFB1 showed more intense dystrophic changes – necrobiotic to necrotic changes of intestinal villi, atrophy of Lieberkühn glands, mononuclear cell infiltration of the propria and severe rarefaction of lymphatic follicular cells. The dietary supplementation of chickens with Mycotox NG resulted in fewer and less severe histological changes – no haemorrhagies but only vascular hyperaemia.


Stimulating feeding and development of hypopharyngeal and thoracic glands of honeybees (Apis mellifera L.)

R. Shumkova1, I. Zhelyazkova2*

1Experimental Station of Stockbreeding and Agriculture, 4700 Smolyan, Bulgaria
2Department of Animal Science, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The effect of some stimulating products on the development of the hypopharyngeal (HPhG) and the thoracic glands (ThG) of worker bees was studied. The investigation was conducted in the spring period of 2012 at the Experimental apiary of the Experimental Station of Stockbreeding and Agriculture (ESSA) in Smolyan, Bulgaria. Products ‘Vita Feed Gold (VFG)’, ‘Apidas’, ‘Oligofosi’ and ‘Anolyte-7’ were used for stimulating feeding of bee colonies. Five groups, each of five bee colonies were formed. Samples from bees for investigation of HPhG and ThG were taken after finishing the feeding. The state of glands was determined in non-flying 5-10-day worker bees (30 from each colony). The 4-point scale of Hess (in rates, Maurizio, 1954) is used for establishing the degree of development of hypopharyngeal glands. The diameter of 10 glandular blebs of HPhG of each bee is additionally measured. Height and diameter of 10 glandular tubes are measured and their volume is calculated for determining the degree of development of the thoracic glands of each bee. Binocular loupe MBS-1 with ocular micrometer is used for measurement. It is established that with the highest degree of development are HPhG of worker bees (3.90±0.06 rates and 0.102±0.0017 mm diameter of glandular blebs), receiving with their food ‘VFG’ – respectively, 1.06 and 1.27 times more than bees from the control group. From the studied stimulating products, the preparation ‘Apidas’ (includes plant extracts) is also with well expressed positive effect on the development of HPhG of bees. The obtained values of the studied parameter in bees receiving ‘Anolyte-7’ (electrochemically activated water solution) and those of the control group are commensurable. Positive influence of preparations ‘Apidas’ and ‘VFG’ on the volume of the measured glandular tubes from the thoracic glands of worker bees is determined. The reported values for volume of glandular tubes in bees receiving with their food the indicated stimulating preparations (0.005 and 0.004 mm3) are 2.0 – 2.5 higher than the studied parameter in bees from the control group (0.002 mm3) and those fed with ‘Anolyte-7’ (0.002 mm3) and ‘Oligofosi’ (0.001 mm3).