Economic values of productive and functional traits in sheep of Bulgarian dairy synthetic population

S. Slavova*, S. Laleva

Agricultural Institute, 6000 Stara Zagora, Bulgaria

(Manuscript received 4 September 2020; accepted for publication 8 March 2021)

Abstract: The subject of the current research was to calculate profitability and economic values of production and functional traits in sheep of Bulgarian dairy synthetic population, reared at the Agricultural Institute – Stara Zagora. The study period was 7 years (2010-2016) and the average annual number of ewes in the flock was 188. The semi-intensive production system practised involved winter indoor lambing and summer grazing on pasture. Data were processed using the Program for calculating economic weights for sheep EWSH2. Profit and profitability in the flock had negative values – (-52.70 BGN) and -19.3%. Marginal economic values of the most important traits in dairy sheep – milk production and number of lambs born per ewe were estimated to 0.707 BGN per liter and 65.40 BGN per lamb, respectively. Litter size, milk yield, conception rate of ewes and ewe lambs and productive lifetime of ewes showed the highest economic importance. A very low economic weight was calculated for the wool production due to the market prices of wool. Conception rate of female animals and productive lifetime of ewes need to be more thoroughly investigated, as they are not currently an object of selection in dairy sheep breeding. Achieving competitive and economically sustainable productive systems in sheep farming is associated with a constant desire to increase the economic value of animals.

Non-parametric decomposition of total factor productivity growth in yam production in North-Central Nigeria

R.G. Isonguyo*, M.A Ojo, A.J. Jirgi, E.S. Yisa

Department of Agricultural Economics and Farm Management, Federal University of Technology, Minna, Nigeria

(Manuscript received 5 October 2020; accepted for publication 18 February 2021)

Abstract. Non-parametric analysis of total factor productivity change in yam production in North-Central Nigeria from 1992 to 2016 was carried out with the use of secondary data. The secondary production data of yam for that period were collected from Food and Agriculture Statistical (FAOSTAT) data bank. Malmquist Total Factor Productivity Index (MTFPI) based on Data Envelopment Analysis (DEA), was used to empirically analyse the total factor productivity of the yam, while Tobit regression was used to analyse the determinants of total factor productivity in the study area. The results of the MTFPI analysis reveal that yam contributed 1.4% of technical efficiency change to productivity growth over the period studied. The technological contributions to productivity growth regressed at 1.8%. The study revealed the productivity growth of yam to be 0.2%. Tobit regression result showed credit borrowed, government policy (Agricultural Transformation Agenda – ATA), capital, and labour to have significant and positive relationships with the productivity of the crop at either p≤0.05 or p≤0.001 level of probability, which implies that increase in them led to increase in the crop’s productivity. Capital-labour was statistically significant but negatively related to yam productivity at p≤0.01, which implied that utilization of labour in a greater proportion than capital led to reduction or regress in its productivity growth. The study recommends farmers’ training on farm practices and techniques to increase yam productivity. They should be encouraged to accept improved yam varieties from research institutes, properly allocate the production resources and adopt improved technology to achieve productivity growth in the study area.

Nutritional and functional attributes of raw and grilled crabmeat

R.O. Moruf1*, M.A. Taiwo2, Q. Adebayo2

1Department of Fisheries and Aquaculture, Bayero University, Kano, Nigeria
2Department of Food Science and Technology, Federal University Dutsin-Ma, Nigeria

(Manuscript received 4 November 2020; accepted for publication 15 February 2021)

Abstract. Crab is a good source of animal protein, eaten either as snacks or as part of main meal in Southern Nigeria. The effect of grilling on energy-providing nutrients and functional attributes of Cardiosoma armatum (Herklots, 1851) were determined. The comparison of the raw and grilled crabmeat showed that grilling had considerable effect on the quality of this species. Significant changes (p<0.05) in crude fiber (%), calcium (mg/100g), magnesium (mg/100g), potassium (mg/100g), sodium (mg/100g), and oil absorbing capacity (%) were observed after grilling. Utilizable energy due to protein (60% of protein energy utilization assumed) was comparable in both raw (9.36 kJ/9.27 kcal) and grilled samples (10.92 kJ/10.83 kcal). The ratio, Ca/Mg was high with a little variation between the two samples, having coefficient of variation percent of 12.94%. Only calcium had its Mineral Safety Index (MSI) greater than the standard value for both the raw samples (23.68>10.00) and the grilled samples (13.86>10.00). All the significant energy-providing nutrients have a positive correlation with the investigated minerals except magnesium. Grilling was found to be a suitable cooking process for C. armatum, since it conserved the main energy-providing nutrients and functional characteristics.

Isolation and characterization of Lactobacillus microflora from homemade white sheep’s milk cheeses during ripening

S. Stojanovski1*, G. Cilev2, B. Trajanoska3

1Department of Microbiology, Faculty of Veterinary Medicine, University “St. Kliment Ohridski”, 7000 Bitola, North Macedonia
2Department of Food Quality and Safety, Faculty of Veterinary Medicine, University “St. Kliment Ohridski”, 7000 Bitola, North Macedonia
3Veterinary clinic “Makseraja”, 7500 Prilep, North Macedonia

(Manuscript received 24 September 2020; accepted for publication 1 February 2021)

Abstract. The Lactobacillus microflora of white cheese made from sheep’s milk was studied during the maturation period of 10 to 100 days in the basement at a temperature of 10-12°C. Eight samples from different stages of natural white cheese ripening were taken for testing. A total of 28 strains were isolated and identified as Lactobacillus spp. based on their growth, gram-stain activity, catalase and oxidase. Their affiliation to this genus was confirmed by PCR with genus specific primers, 16S ribosomal RNA. The results show that in the early stages of cheese ripening (5th-6th, 10-39 day) the most commonly found species are: Lactobacillus plantarum and Lactobacillus curvatus, while in later stages of the cheese ripening (7th-10th, 40-80 day), the following species are found: Lactobacillus plantarum and Lactobacillus paracasei subsp. Paracasei.

Main parameters of essential oil of two species from genus Pelargonium, cultivated in laboratory conditions

V. Badzhelova*

Institute of Roses, Essential and Medical Cultures, 6100 Kazanlak, Bulgaria

Manuscript received 24 July 2020; accepted for publication 20 January 2021

Abstract. The objective of this study is to determine the quantity and parameters of the obtained essential oil of two species from genus Pelargonium (Pelargonium graveolens L’Her. and Pelargonium radens H.E.Moor) in Bulgaria. This research was conducted using the microdistillation method and gas chromatography. As a result significant difference in the quantity of obtained essential oils has been found and the number of the main components and the ratio of the dominant ingredients have been determined. In general, they represent the main part of the oils – from 45.23 % in Pelargonium radens to 47.60 % in Pelargonium graveolens, respectively. The highest is the content of citronellol+nerol in both species, 38.88 % for Pelargonium radens and 37.97 % for Pelargonium graveolens.

Assessment of morphological variations in wild populations of Nile tilapia from South West Nigeria

O.M. Popoola*, A. Ebiwonjumi

Department of Fisheries and Aquaculture, Federal University of Technology, Akure, Nigeria

(Manuscript received 31 October 2020; accepted for publication 20 February 2021)

Abstract. The pattern of morphological variations among Oreochromis niloticus (Linnaeus, 1758) (Cichlidae; Teleostei) from three populations from South West Nigeria (Asejire reservoir, Ureje reservoir and Ogbese River were examined (n=10 speciments from each water body) with a view to investigate the genetic diversity using morphometrics and meristics indices. In general, 77.22% of the total variation in the sampled populations is from first principal component (PC1) and the characters that contributed to this variation are with pre-dorsal length, pre-pectoral length, pre-anal length, dorsal spine length and anal spine length. Canonical variate analysis (CVA) showed that O. niloticus populations from the three water bodies formed a separate cluster from each other and that there was an intersection between the Asejire and Ureje reservoirs samples and the Asejire reservoir with Ogbese River samples. However, the samples from Ureje reservoir and Ogbese River had no intersection. Cluster analysis revealed two major clusters with Ureje reservoir samples belong to one and Ogbese River and Asejire reservoir fall in the other cluster. Principal Components for meristic (PC1 and PC2) accounted for 46.49% and 24.17% revealed that transverse scales and scales surrounding the caudal peduncle, pre-dorsal scales accounted for the variation. The CVA revealed that of all the populations sampled, samples from Ureje reservoir are more diverse that the other two populations. The research disclosed that there is variation in O. niloticus populations from the three water bodies, which could be a result of genetic structure and environmental conditions, being major factors affecting morphological variability among different geographical populations. Further study on genetic differentiation of individuals from different species is necessary to confirm findings of the present study.

Physiological responses of Vicia faba to copper toxicity

S. Benouis1,2*, H.A. Reguieg Yssaad1, E.H. Bouziani1, I. Khedim1

1Laboratory of Biodiversity and Conservation of Water and Soils, Faculty of Nature and Life Sciences, University of Abdelhamid Ibn Badis, Mostaganem, Algeria
2Scientific and Technical Research Center on Arid Regions (CRSTRA) Biskra, Algeria

(Manuscript received 21 July 2020; accepted for publication 26 February 2021)


Abstract. Copper plays an important role in multiple plant physiological processes including photosynthesis and protein synthesis. Excess copper in tissues leads to physiological and biochemical disturbances. In order to determine the physiological response of Vicia faba L. to copper toxicity, two varieties (Sidi Aïch and Super Aguadulce) were grown in a substrate of sand and compost (3V/V) and contaminated by different doses of Cu (0, 80, 160, 240, 320, 400 mg kg-1). Dose rates ≥160 mg kg-1 led to the accumulation of copper in roots and shoots, in turn leading to decreases in photosynthetic activity and protein content and to the accumulation of proline, a stress indicator, and soluble sugars.

Productivity and feed quality of Sudan grass (Sorghum sudanense (Piper) Stapf.) and sweet sorghum forms

S. Enchev*

Agricultural Institute, 3 Simeon Veliki, 9700 Shumen, Bulgaria

(Manuscript received 24 August 2020; accepted for publication 22 February 2021)

Abstract. During the period 2017-2018, the feed quality and productivity of three Sudan grass varieties – Endje 1, Vercors and Super Sweet, one stabilized Sudan grass population – SWT, local sweet sorghum – „Zaharna metla“ population and the sweet sorghum cultivar “Shumensko sladko” were researched in Agricultural Institute – Shumen. Green mass (t/ha), dry matter (%) and dry mass production (%) as well as basic nutritional characteristics by the two swaths of the tested cultivars in brooming phase were controlled. It was found that the sweet sorghum cultivar “Shumensko sladko” gave the highest amount of green mass – 59.5 t/ha by two swaths, and the dry mass yield was the highest from the cultivar Endje 1 – 20.8 t/ha. In terms of chemical composition, the greatest variation was demonstrated in phosphorus content (0.369-0.696%, CV=27.3%), followed by crude fat (1.28-2.39%, CV=26.8%), Ca (0.889-1.572%, CV=21.8%), crude protein (6.05-9.00%, CV=14.6%), nitrogen free extracts (42.05-51.20%, CV=7.6%), crude fiber (32.64-39.26%, CV=6.1%) and mineral substances (8.17-9.61%, CV=5.9%). It can be summarized that all hybrids provide quality hay, however the Bulgarian cultivars Endje 1 and “Shumensko sladko” showed the best nutritional value – compared to Super Sweet, Vercors, SWT and “Zaharna metla”.

Influence of long-term fertilization and environments on test weight of durum wheat (Triticum durum Desf.) grain

G. Panayotova1*, S. Kostadinova2, S. Stefanova-Dobreva3, A. Muhova3

1Department of Plant production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Agrochemistry and Soil Science, Faculty of Agronomy, Agricutural University, 4000 Plovdiv, Bulgaria
3Field Crops Institute, 6200 Chirpan, Bulgaria

(Manuscript received 6 September 2020; accepted for publication 26 February 2020)

Abstract. The aim of this study was to investigate the influence of long-term nitrogen-phosphorus fertilization and meteorological conditions during the period 1990-2019 on test weight of durum wheat grain in Central South Bulgaria. The influence of nitrogen and phosphorus rates – 0, 40, 80, 120 and 160 kg.ha-1, as well as combined NP fertilization in the same rates on durum wheat grain under conditions of stationary long-term fertilizing experiment in cotton-durum wheat crop rotation was studied. The analysis of the results showed that the test weight was below the standard requirements in eight of the studied years, and in 22 years the average test weight exceeded the requirements. The values in 17 years were over 80.0 kg. The test weight decreased by increasing the N rates above 80 kg and the lowest average value was seen at N160 – 79.4 kg. The Р application in rates from 40 tо 160 kg.ha-1 indicated a tendency to increase the test weight. Good values were realized by combining a moderate to high phosphorus rates Р80-160 with low N levels N40-80. Weather conditions during the 30-year period have a strong significant impact on the test weight of the grain.

Length-weight relationship of European catfish (Silurus glanis L.) fry reared at different stocking densities under controlled conditions

V. Krasteva*, M. Yankova

Institute of Fisheries and Aquaculture, 4003 Plovdiv, Bulgaria

(Manuscript received 14 October 2020; accepted for publication 18 January 2021)

Abstract. The present paper investigates the body length and weight, and the size-weight variations of one-month-old European catfish reared at 4 variants of stocking density: Variant 1 – 5 spec/l; Variant 2 – 10 spec/l; Variant 3 – 15 spec/l and Variant 4 – 28 spec/l. The experiment is carried out at the Institute of Fisheries and Aquaculture, Plovdiv for a period of 16 days, using a production system consisting of tubs with continuous water flow (0.7 l/min). At the end of the experiment, the fish from each variant are sorted in three size-weight groups: A – large, B – medium and C – small. The number of fish in each group is established. From the group of the medium- and small-sized fish, 150 speciments are measured, while from the group of the large specimens, which are the smallest in number, all specimens are measured for the biometric parameters body weight (BW, g) and total body length (TL, cm). The results from the study show small variations in the length and weight of the fish reared at the lowest stocking density (Variant 1). As the density increase, the size-weight differences between the specimens from Group A also increased, while of those from Group B they decrease. The number of the medium-sized fish decrease (p≤0.001) while the number of large specimens (p≤0.01) and small fish increase (p≤0.001).