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).


Potential N-supplying ability of soil depending on the size of soil units under different tillage systems

M. Nankova1*, P. Yankov2

1Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
2Department of Plant Production, Faculty of Marine Sciences and Ecology, Technical University, 1 Studentska, 9010 Varna, Bulgaria

Abstract. The effect of the different soil tillage systems on the mineralization ability of the slightly leached chernozem soil (Haplic Chernozems) has been investigated in a stationary field trial carried out at Dobrudzha Agricultural Institute, General Toshevo since 1987. The trial was designed by the non-standard method, with size of the trial plots 72 m2. The investigation was performed under the following annually applied soil tillage systems: plowing, disking, cutting and nil tillage, as well as under three alternated soil tillage systems plowing-disking, plowing-nil and disking-nil. The potential nitrogen-supplying ability of soil (NO3- N mg/1000 g soil) was estimated in soil samples taken from depth 0 –10, 10 – 20 and 20 – 30 cm after harvesting of wheat. Soil was filtered through a series of sieves with apertures 10, 5, 3, 1 and 0.25 mm, respectively. Thus the following soil fractions were obtained: >10 mm, 5 –10 mm, 3 – 5 mm, 1 – 3 mm, 0.25 –1 mm and <0.25 mm. The analyses were made in air-dry soil. Composting was done in a thermostat under controlled temperature conditions 30oС and 60% of marginal soil moisture absorbtion of soil in dynamics after 14, 28 and 56 days of incubation. The potential nitrogen-supplying ability of soil was strongly influenced by the type of the tillage system. Maximum amounts of nitrified nitrogen under all soil tillage systems were determined after 56-day incubation. The rate of pure mineralization was highest between the 14th and the 28th day. Under optimal conditions for occurrence of nitrification, the systems which involved plowing were able after 14-day incubation to mineralize greater amounts of nitrogen in comparison to the reduced types of soil tillage and the tillage without turning of the soil layer. The potential of nitrogen mineralization under constant disking, direct sowing and tillage without turning of the soil layer at long-term favorable conditions for the occurrence of nitrification (28 and 56 days) was higher than the potential under the systems involving plowing. In the surface layers, the small-sized structural soil units (0.25-1 mm and <0.25 mm) contributed significantly to the higher mineralization ability of soil. At depth 20–30 cm the tendency remained the same under the systems involving plowing. The correlation of the mineralization ability with ammonium nitrogen content was better expressed than the correlation with nitrate nitrogen content. Mineralized nitrogen showed high and permanent correlations till the 28th and the 56th day from the incubation period.


Feeding value estimation of spring forage pea (Pisum sativum L.) in organic cultivation

I. Nikolova, N. Georgieva, Y. Naydenova*

Institute of Forage Crops, 89 General Vladimir Vazov, 5800 Pleven, Bulgaria

Abstract. The isolated and combined action of organic products Biofa (foliar fertilizer), Polyversum (growth regulator), NeemAzal and Pyrethrum (biological insecticides) on energy and protein feeding value of the dry mass of spring forage pea grown in the conditions of organic farming is studied. As a standard of comparisonthesyntheticproductsFlordimeks(plantgrowthregulator)andNureleE(insecticide)areusedaloneorincombination. Thefieldexperimentis conducted in the period 2011 – 2013 at the Institute of Forage Crops, Pleven, Bulgaria. Treatments are performed once in budding and twice in budding and flowering vegetative stages for control of economically important pests. It is found that treatment with organic products in the budding stage influences the energy feeding value positively, increasing it from 0.6 to 5.2% for UFL and from 0.7 to 7.1% for UFV. The highest energy feeding value distinguished combined introduction of Nimazal and Polyverzum (UFL – 0.850 and UFV – 0.768). Double use of biological preparations is associated with a pronounced increase in forage energy feeding value from 1.1 to 9.2% for UFL and from 0.9 to 11.9% for UFV. Compared to a single treatment, an average five- and four-fold increase is established for UFL and UFV, respectively. The treatment with biological regulator Polyverzum has the greatest impact (0.864 and 0.783 for the UFL and UFV), followed by Polyverzum+NeemAzal (0.856 and 0.773 for the UFL and UFV). Protein feeding value in a single treatment is decreased by 5.6% on average. Only Biofa treatment leads to an increase of 15.3% (PBD – 117.6). Double-application is associated with an increase of the forage protein feeding value from 0.2 to 14.4% for the PBD, from 0.1 to 9.8% for PDIN and from 1.8 to 6.4% for PDIE. The highest values distinguished the treatment with NeemAzal (PBD – 99.1; PDIN – 82.3; PDIE – 91.0), followed by NeemAzal+Biofa (PBD – 99.8; PDIN – 89.7; PDIE – 89.2) and Pyrethrum + Polyverzum (PBD – 97.1; PDIN – 88.1; PDIE – 89.0).Syntheticproducts,irrespectiveofthevegetativestageofsubmission,leadtoanincreaseofparameterswhichcharacterizethe forageenergyfeeding value and protein feeding value, but in a relatively lower degree.


The performance of female dairy calves fed texturized starters with different protein sources

E. Yavuz1, N. Todorov1*, G. Ganchev1, K. Nedelkov2

1Departmet of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Animal Husbandry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The aim of the experiment was to determine the effect of inclusion of dry distillers grain with solubles (DDGS) and canola meal, as replacement of soybean meal and sunflower meal in textured starter feed for dairy calves. The second object was to compare two starters with the same ingredient and nutrient content composed of whole maize grain (WMG) plus protein concentrate, versus mixture of WMG, pelleted DDGS, pelleted canola meal, and pelleted mineral- vitamin premix. A seventy-day experiment was carried out with 30 Black and White female calves weighing 39 kg at birth. Each calf received 2 L of high quality colostrum (above 50 mg immunoglobulin/L) three times during the first day and 2 L colostrum three times at the second day after birth. From 3 to 35 days of age, calves were fed 3 L pasteurized whole unsalable milk twice daily and from 36 to 56 days of age – once daily. Calves were allocated to three treatments based on the day of birth and weight at birth. The calves received texturized starter feed with different composition: 1) 50% whole maize grain (WMG) + 50% pelleted protein concentrate with soybean meal, DDGS and sunflower meal as protein sources for the first group (pBDS); 2) 50% WMG + 50% pelleted protein concentrate withDDGSandcanolamealforthesecondgroup(pDC);3)50%WMG+24.1%pelletedDDGS+23.4%,pelletedcanolameal +2.5%pelleted mineral-vitaminpremix forthethirdgroup(DCVp).Crudeprotein(CP)contentofallthreestarterswas19.0to19.6%.From1to35daysofagetheaverage daily gain (ADG) was 606, 580 and 569 g respectively for pBDS, pDC and DCVp groups, and did not differ (P>0.05) among treatments. From 36 to 56 days of age the ADG was 719, 710 and 695 g (P>0.05), and from 57 to 70 days 971, 964 and 943 g (P>0.05) respectively for pBDS, pDC and DCVp groups. There were no significant differences in feed efficiency, fecal score, health status and behavior of calves receiving different starter feeds. Results of this trial indicated that it is possible to replace soybean meal plus sunflower meal with canola meal and dry distillers grain with solubles, without significant changes of ADG, feed efficiency and health status of calves. Performance of calves was approximately equal when fed DDGS and canola meal as ingredients of pelleted protein concentrate or as separate ingredient in a starter mixture of WMG, pelleted DDGS, pelleted CM and pelleted mineral-vitamin premix. When pelleted DDGS and pelleted canola meal is available, it is possible to use them directly as components of starter, instead of buying protein concentrate with the same protein sources. Starter feed containing whole maize grain, pelleted DDGS, pelleted canola meal, and pelleted mineral-vitamin premix was the cheapest, compared to the other tested starter feeds.


Effect of linseed and sunflower oils in the diet on the growth parameters in rainbow trout (Oncorhynchus mykiss W.) cultivated in a recirculating system

G. Zheliazkov*

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The aim of this study was to determine the influence of linseed and sunflower oils in the diet on the survival rate, weight gain and the feed conversion ratio in rainbow trout, reared in a recirculating system. The fish of the three groups were raised in concrete tanks with effective capacity of 0.8 m3, which were part of the recirculating system. Rainbow trout received extruded feed (6 mm pellets), produced by “Aqua garant”. The feed of the fish from the experimental group (EL) was supplemented with 5% linseed oil, while that of the trout of the group (ES) – 5% sunflower oil. The diet of the fish of the control group (C) did not contain any of the above mentioned oils. The duration of the trial was 60 days. In order to study the effect of linseed and sunflower oils in the diet on the weight gain of the fish, control catches were carried out at 15 days’ interval. The live weight (g) and linear growth (mm) of the control catches were determined as the fish were individually weighed and measured. The final live weights of the trout in the experimental groups as well as that in the control were as follows: EL – 334.79±67.52g, ES – 329.39±70.31 g and C – 323.58±67.77 g. The values of this parameter in EL were higher than those of fish from ES and the control group by 1.64% and 3.47%, respectively, but the differences were not significant (P>0.05). This trend persisted also for the linear measurements – in the trout of EL they were the highest. The fish of EL displayed the lowest feed consumption. This trait had lower values than the ones of the trout of ES and the control group by 2.84% and 5%, respectively, though the differences were not significant (P>0.05). The survival rate of the fish from the groups did not differ substantially.