Study of the effects of low temperatures on the morphological status of ram spermatozoa

The aim of the study was to evaluate how the process of cryopreservation influenced the morphological status of ram sperm. The experiment was carried out with 26 sexually matured, pure bred rams during their breeding campaign. The animals were divided in two groups according to the breed – 15 rams from Synthetic Population of Bulgarian Milk (SPBM) and 11 rams from Sofia breed (SB). The sperm morphology was evaluated under microscope (Nikon Eclipse E200, Japan) by staining with SpermBlue (Microptic, Spain), performed according to the manufacturer's protocol, and observed under bright field with magnification of ×40. Cryopreservation of semen straws was done by the method of Cassou (1964). After cryopreservation, the percentage of spermatozoa with normal morphology decreased and those with abnormal morphology increased. This difference was more pronounced at rams from SPBM compared to SB rams. After freezing, the percentage of spermatozoa with damage to the head at rams from both breeds increased. The percentage of the spermatozoa with damage in the midpiece and the tail was higher and significant (P<0.001) for the SPBM rams. The low temperatures of cryopreservation had a detrimental effect to the rams’ sperm structures. This damaging effect was much stronger for the rams from SPBM breed compared to rams from Sofia breed

Uticaj dodavanja neorganskog i organskog selena na kvalitet i količinu sperme ovnova severoistočne bugarske merino rase

Selenium is a trace element, which stimulates antioxidant defenses and improves reproductive functions in human and animals, under the form of selenoproteins. The objective of the study was to evaluate the effect of selenium, supplemented as inorganic or organic form in the diet of stud rams, on some of their semen parameters. The experiment was performed with 15 clinically healthy rams from North East Bulgarian merino breed. The animals were divided in three groups (5 per group). The rams from first experimental group (G1) received a diet with supplementation of 4,0mg sodium selenite (Na2SeO3) per animal per day, while the animals of the second experimental group (G2) obtained diet with 1.83g L-selenomethionine (Sel-Plex, Alltech, USA) per animal per day. Eventually, each animal from the G1 and G2 received 1.83g selenium per day. The control group (GC) received a diet without supplementation of selenium. The principal composition of the diet in each group was the same. The ejaculates were obtained via artificial vagina. The evaluated parameters were volume and pH of the ejaculates and motility, concentration and in vitro survivability of the spermatozoa at 39˚S for 360 min. It was found that the supplementation of ram studs diet either with inorganic and organic selenium led to increase in the volume of the ejaculates, motility and survivability of the spermatozoa. The pH of the freshly obtained semen was not affected by selenium treatment.Selen je element u tragovima, koji stimuliše antioksidantske odbrane i poboljšava reproduktivne funkcije kod ljudi i životinja, u obliku selenoproteina. Cilj studije je bio da se proceni efekat selena, dopunjenog u neorganskom ili organskom oblik u ishrani ovnova, na neke parametre semena. Eksperiment je obavljen sa 15 klinički zdravih ovnova severnoistočne bugarske merino rase. Životinje su podeljene u tri grupe (5 po grupi). Ovnovi prve eksperimentalne grupe (G1) dobijali su obrok sa dodatkom 4,0 mg natrijum selenita (Na2SeO3) po grlu dnevno, dok su životinje druge eksperimentalne grupe (G2) hranjene obrokom sa 1,83 g L-selenometionina (Sel- Plek, Alltech, SAD) po grlu dnevno. Na kraju, svaka životinja iz G1 i G2 dobijala je 1,83g selena dnevno. Kontrolna grupa (GC) dobila je obrok bez dodatka selena. Glavni sastav obroka u svakoj grupi bio je isti. Ejakulati su dobijeni preko veštačke vagine. Ocenjivani su sledeći parametri: volumen i pH ejakulata i pokretljivosti, koncentracija i preživljavanje in vitro spermatozoida na 39°C tokom 360 min. Utvrđeno je da dodatak obroku neorganskog i organskog selena doveo do povećanja zapremine ejakulata, pokretljivosti i preživljavanja spermatozoida. Na sveže dobijeno seme nije uticao tretman sa selenom

Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation

The aim of the present study was to determine a possible relationship between sperm parameters and activity of creatinine kinase (CK) in the process of cryopreservation. To achieve this goal, 14 ejaculates of 7 rams of the breed Ile de France, aged 3-5 years, were examined. The rams were breeding under the same conditions of feeding, growing and sexual use. Ejaculates were obtained via the artificial vagina method and were diluted 1:12 with 6 A-G extender. The resulting ejaculates were examined by a computer assisted semen analysis (CASA) to determine total motility, velocity parameters, and morphological status. The intracellular and extracellular activity of CK were determined spectrophotometrically. After sperm evaluation, the ejaculates were frozen using Cassou sequin technology and the same parameters were analyzed after thawing the samples. From the obtained results we found a 26% decrease in sperm motility after thawing. The velocity parameters for VCL, VSL, VAP, AHL and BCF also decreased significantly after thawing (P≤0.01), but an increase was found in the linear velocity parameters - LIN, STR and WOB (P≤0.01). Cryopreservation also increased the percentage of abnormal sperm by 17%. A higher intracellular CK activity, which decreased significantly after freeze-thawing (P≤0.001) was measured. In conclusion, cryopreservation decreased sperm motility and increased the percentage of abnormal sperm (mostly with tail damage), but we did not establish a relationship between linear the velocity parameters LIN, STR and WOB, sperm morphological status and CK activity. Therefore, CK activity cannot serve as an indicator of sperm quality in the process of cryopreservation

Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams

Selenium is a trace element, which stimulates antioxidant defenses and improves reproductive functions in human and animals, under the form of selenoproteins. The objective of the study was to evaluate the effect of selenium, supplemented as inorganic or organic form in the diet of stud rams, on some of their semen parameters. The experiment was performed with 15 clinically healthy rams from North East Bulgarian merino breed. The animals were divided in three groups (5 per group). The rams from first experimental group (G1) received a diet with supplementation of 4,0mg sodium selenite (Na2SeO3) per animal per day, while the animals of the second experimental group (G2) obtained diet with 1.83g L-selenomethionine (Sel-Plex, Alltech, USA) per animal per day. Eventually, each animal from the G1 and G2 received 1.83g selenium per day. The control group (GC) received a diet without supplementation of selenium. The principal composition of the diet in each group was the same. The ejaculates were obtained via artificial vagina. The evaluated parameters were volume and pH of the ejaculates and motility, concentration and in vitro survivability of the spermatozoa at 39˚S for 360 min. It was found that the supplementation of ram studs diet either with inorganic and organic selenium led to increase in the volume of the ejaculates, motility and survivability of the spermatozoa. The pH of the freshly obtained semen was not affected by selenium treatment

Importance, productivity and potentials of local Serbian sheep breeds

Due to the political, demographic and economic situation, agriculture in Serbia changed, including also the structure in sheep breeds. Traditional sheep breeding centers with large pasture areas and large number of local breeds and strains are deserted, and, consequently, sheep production focused on meat production, in intensive systems, but in expensive and inadequate ways. This led to decreasing number in local breeds (pramenka) with its strains. In this research, two most numerous pramenka strains were observed, Sjenica and Svrljig strains, concerning their number, productive and reproductive parameters. Population of registered and active heads in 2020. was 139,319 for Sjenica and 19585 for Svrljig strain. Weight on birth for Sjenica and Svrljig lambs were 3.20 and 3.15, while weight after 30 days and on weaning was 11.06, 11.42 and 27.02 and 24.97, respectively. Lambing index was 1.27 for Sjenica and 1.29 for Svrljig strain. Svrljig strain had longer lactation (104 vs. 88 days), with higher milk production (64.05 kg vs. 55.01 kg), but protein content was higher in Sjenica sheep’s milk (5.08% vs. 4.19%). Besides their importance on agro-biodiversity and genetic pool, these strains are best adapted for breeding conditions that are in hilly and mountainous parts of Serbia. As triple production strains, their milk, meat and wool could be used in processing to traditional, high-quality products with additional value, so can provide extra income for the farmers which leads to survival and sustainable development of rural areas

Seasonal variations in enzyme activity in Ovies aries seminal plasma

Sheep (Ovies aries) are mainly seasonal polycyclic animals. Sperm production is influenced by many factors, including daylight length, climate temperature, humidity, and melatonin secretion, with females becoming fertile in early autumn and remaining fertile through mid-winter (October-February). Seminal plasma is a complex fluid that is functional modulator of sperm function known to inhibit and stimulate sperm function and viability. Some seminal plasma proteins are capable of binding to the sperm plasma membrane and have an important role in sperm capacitation and egg fertilization. A variety of enzymes in the seminal plasma protect the sperm membrane from ROS-induced damage and lipid peroxidation through the activity of the antioxidant enzyme defense system. Regarding this, the aim of our study is to determine the biochemical changes that occur during the breeding campaign of the species Ovies aries and beyond. To fulfill the set goal, we have examined 6 ejaculates spectrophotometrically. As a result, we found higher antioxidant enzyme protection outside the insemination campaign in glutathione (GSH) concentration and glutathione peroxidase (GPx) activity and non-significant differences in glutathione reductase (GR) activity. The enzyme activities of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were higher during breeding season of the animals. In conclusion, a higher protective antioxidant system may help ensure adequate sperm fertilization potential when reproductive conditions are suboptimal. However, further research is needed to determine the mechanisms of action of the antioxidant enzyme and the relationships between indicators for determining sperm quality

Changes in the Oxidative Status of Dual-Purpose Hens Rearing in the Free-Range System during Cold, Thermoneutral and Hot Period

This study aimed to assess the changes in the oxidative status of six genotypes of free-range laying hens during cold, thermoneutral, and hot periods by measuring the levels of lipid peroxidation (LPO), total glutathione (tGSH), and the activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in erythrocyte suspension, in relation with their egg production. Two identical experiments were conducted in two consecutive years. Thermal stress adversely affected the oxidative status of hens. The induced OS is expressed by an increase in LPO and the activities of antioxidant enzymes SOD and GPx during cold and hot periods and a decrease in CAT and tGSH during the cold period in both years. The factor “temperature period”, compared to “year” and “genotype”, had the most significant influence on all biochemical parameters (p p < 0.05) were detected among studied biochemical parameters, except between SOD and tGSH. The chicken genotypes showed differences in their susceptibility to OS and this had an effect on egg production—from 37.87% to 74.93%. The OS is genotypically specific and can play a significant role in determining welfare and egg production in free-range systems

Effects of anthropogenic and environmental stressors on the current status of red mullet (Mullus barbatus L., 1758) populations inhabiting the Bulgarian Black Sea waters

The red mullet (Mullus barbatus Linnaeus, 1758) is a keynote species for the Bulgarian Black Sea ecosystem and fisheries; nevertheless, existing knowledge on population status is very scarce. The present study was intended to assess the health status and adaptive potential of M. barbatus populations inhabiting the Bulgarian waters of the Black Sea. Our findings revealed that populations of M. barbatus are exposed to a variety of anthropogenic and environmental stressors. The species’ status was assessed using representative genetic, morphological, biochemical and chemical biomarkers from specimens obtained in the research area’s northern and southern regions. Based on mtDNA markers, genetic analysis revealed low haplotype and nucleotide diversity, typically observed in overexploited or “threatened” populations. Examining the morphology of the specimens revealed no discernible pattern of differentiation. Except for aluminium and chrome, metal and PAH concentrations in fish were below the regulatory thresholds. The specimens from the southern region ingested more microplastics than those from the northern region. The majority of specimens collected from the southern region also exhibited elevated levels of oxidative stress and decreased antioxidant defence, which can be interpreted as an early indication that they had reached the limits of their adaptive potential. Further research on the composite effects of the stressogenic environment on the Black Sea biota are critically needed, as well as the introduction of new indicators and thresholds at molecular and cellular levels for adequate monitoring of both the ecological state of the marine environment and its biota

Effects of anthropogenic and environmental stressors on the current status of red mullet (Mullus barbatus L., 1758) populations inhabiting the Bulgarian Black Sea waters

The red mullet (Mullus barbatus Linnaeus, 1758) is a keynote species for the Bulgarian Black Sea ecosystem and fisheries; nevertheless, existing knowledge on population status is very scarce. The present study was intended to assess the health status and adaptive potential of M. barbatus populations inhabiting the Bulgarian waters of the Black Sea. Our findings revealed that populations of M. barbatus are exposed to a variety of anthropogenic and environmental stressors. The species’ status was assessed using representative genetic, morphological, biochemical and chemical biomarkers from specimens obtained in the research area’s northern and southern regions. Based on mtDNA markers, genetic analysis revealed low haplotype and nucleotide diversity, typically observed in overexploited or “threatened” populations. Examining the morphology of the specimens revealed no discernible pattern of differentiation. Except for aluminium and chrome, metal and PAH concentrations in fish were below the regulatory thresholds. The specimens from the southern region ingested more microplastics than those from the northern region. The majority of specimens collected from the southern region also exhibited elevated levels of oxidative stress and decreased antioxidant defence, which can be interpreted as an early indication that they had reached the limits of their adaptive potential. Further research on the composite effects of the stressogenic environment on the Black Sea biota are critically needed, as well as the introduction of new indicators and thresholds at molecular and cellular levels for adequate monitoring of both the ecological state of the marine environment and its biota