Jelena Janjic

The effects of lairage time and handling procedure prior to slaughter on stress and meat quality parameters in pigs

Lairage time (short - 8min to 2.7h, n=28 vs. long - 14 to 21.5h, n=72) and pig handling (gentle - no use of stick or electric prod, pig not slipping, falling, nor emitting high-pitched vocalizations vs. rough - where any of these occurred) effects on pig stress and meat quality were measured. Blood lactate and cortisol, plus post-mortem pH (pH60min; pH24h), temperature (T60min), drip loss, sensory and instrumental color and meat quality for the longissimus dorsi, pars lumbalis derived meat were determined. Carcass rigor mortis and skin damages were measured. Lairage time significantly affected blood lactate, carcass rigor mortis, skin damages, drip loss, color and meat quality. Handling procedure influenced blood lactate, pH60min and T60min. Long lairage was more stressful, and was detrimental to carcass quality, but caused better meat quality compared to short lairage. Rough handling was related to higher lactate and lower meat quality.

Effects of dietary selenium-yeast concentrations on growth performance and carcass composition of ducks

The aim of the present study was to assess effects of selenium (Se)-yeast diet supplementation on performance and carcass composition in ducks. The study was performed on 240 1-day old ducklings of the same origin (Cherry Valley hybrid), during a 49-day period, which were fed diets supplemented with the following four different levels of Se yeast (ALKOSEL® R397): groups with Se at 0 mg/kg of the diet as-fed, 0.2 mg/kg, 0.4 mg/kg and 0.6 mg/kg. Growth performance (bodyweight, daily weight gain, daily feed intake, feed-conversion ratio) and carcass characteristics (hot and cold carcass weight, chilling losses, dressing percentage, carcass cut yields, and percentage of tissues in breast and thighs with drumsticks) of the ducks were determined. Animals fed high-Se diets (0.4 mg/kg) had higher (P < 0.05) final bodyweight and daily weight gain (from 15 to 49 days) compared with those fed diets with inadequate (0 mg/kg) or with supranutritional (0.6 mg/kg) Se levels. Ducks fed only with basal diet showed a higher (P < 0.05) feed-conversion ratio (from 15 to 49 days) compared with those supplemented with Se at 0.4 mg/kg and 0.6 mg/kg. Dressing percentage was higher (P < 0.01) in the control group (69.50%) than in the group with Se added at 0.6 mg/kg (66.85%). The weights of basic cuts from the duck carcasses did not significantly differ among compared groups. Moreover, the percentage of skin with subcutaneous fat in breast and thighs with drumsticks increased in Se-supplemented groups compared with the control group, while the opposite was determined with the percentage of muscle. It was concluded that a diet containing 0.4 mg of added Se per kilogram produced the greatest growth-performance results in ducks.

Inhibition of Salmonella by thyme essential oil and its effect on microbiological and sensory properties of minced pork meat packaged under vacuum and modified atmosphere

The antibacterial activity of thyme essential oil (TEO) was evaluated against four serovars of Salmonella (S. Enteritidis, S. Typhimurium, S. Montevideo and S. Infantis), experimentally inoculated (106CFU/g) in minced pork, which was treated with different concentrations of the TEO (0.3%, 0.6% and 0.9%) packaged under vacuum or MAP (30%O2/50%CO2/20% N2) and stored at 3±1°C for 15days. GC-MS analysis of the TEO was performed in order to determine composition, and the predominant constituent was thymol (50.48%), followed by p-cymene and linalool. The minimum inhibitory concentration was determined for each Salmonella serovar studied. Among the tested active compounds, thymol and carvacrol exhibited the greatest inhibitory effect followed by TEO, with minimum inhibitory concentrations of 320 to 640μg/ml. S. Enteritidis was the most sensitive serovar. During the storage period, Salmonella counts in pork were reduced by 1.69-4.05logCFU/g. The influence of TEO on Enterobacteriaceae, lactic acid bacteria and total viable count was determined in control mince with no added Salmonella. The most pronounced antibacterial effect was achieved by the combination MAP and 0.9% TEO. Although the antibacterial activities of all studied concentrations of TEO in pork were evident and significant (P<0.05), sensory analysis showed that 0.3% TEO was the most acceptable to trained panellists.

Effect of lairage time, behaviour and gender on stress and meat quality parameters in pigs.

The objective of this study was to determine the effects of lairage time (short vs. long), behavior (aggressive vs. non-aggressive) and gender (gilts, barrows and boars) on stress and meat quality parameters in pigs (n = 100). In the group with short lairage, aggressive behavior of gilts and boars was observed. At exsanguination, blood samples were collected and levels of blood lactate and plasma cortisol were determined. Post mortem pH value, temperature, drip loss, sensory and instrumental color and meat quality class were determined on the muscle Longissimus dorsi. Higher blood lactate concentration (P < 0.05) and skin blemish score (P <0.001), lower temperature (P < 0.05) and drip loss (P < 0.01), as well as darker, less red and yellow meat color (P < 0.001) were found after long lairage compared to short lairage. Gilts had higher plasma cortisol concentrations than barrows (P < 0.05), while barrows had lower skin blemish scores (P < 0.05) than gilts and boars after long lairage. The highest incidence of PSE (pale, soft and exudative) meat was observed in barrows (100.00%) and boars (91.67%) after short lairage, while the lowest incidence of PSE meat was found in barrows (28.89%) after long lairage. Aggressiveness affected meat temperature, as aggressive pigs had higher meat temperature (P < 0.05) than non-aggressive pigs.

Seasonal distributions of heavy metal concentrations in different snail (Helix pomatia) tissues from an urban environment in Serbia

The aim of this study was to evaluate the differences between concentrations of heavy metals (cadmium, copper, zinc, iron, and manganese) in terrestrial gastropods, Helix pomatia, collected in four different environment locations in Pančevo city, Serbia. Metal concentrations in the foot and in the digestive gland were measured. Heavy metals cadmium, copper, zinc, iron, and manganese were measured in triplicate by atomic absorption spectrophotometry. Also, this study investigated correlations between the trace element content in the soft tissues and different seasons (summer and fall). The results showed that heavy metal concentrations of the measured elements in both snail tissues were significantly higher in polluted sites when compared to the background levels in the city. In digestive gland tissues, the concentration of heavy metals was higher compared with that in foot tissues. The bioaccumulation (heavy metal concentrations in soft tissues) of heavy metals (Cd, Cu, Zn, Fe, and Mn) in snails, Helix pomatia, has been assessed and related to seasons and sites. Heavy metal accumulation in the soft tissues of snails could provide a powerful monitoring tool for the assessment of environmental heavy metal pollution.

The relationship between the carcass characteristics and meat composition of young Simmental beef cattle

The objective was to study the relationships between the carcass characteristics and meat composition of young Simmental beef, classified with regard to conformation and degree of fatness scores, and total lipid content, depending on gender. For this purpose, 90 animals (60 male and 30 female Simmental beef cattle) were analysed. The results of the study showed that gender affected carcass measurement scores and chemical composition of meat through its important effect on overall animal fatness. Referring to correlations, male carcass conformation score was negatively related to slaughter weight, total lipid content and fatness score. On the other hand, slaughter weight, hot and cold carcass weight, dressing percentage and carcass conformation was positively related to fatness score, all of them being significant. However, female carcass conformation score was positively related to slaughter weight, total lipid content and fatness score. Hot and cold carcass weights of female Simmental beef cattle were positively correlated to slaughter weight, total lipid content and carcass conformation score. Carcass conformation score and fatness score were affected by gender of young Simmental beef cattle.

Effect of modified atmosphere and vacuum packaging conditions on selected chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber scombrus)

Chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber Scombrus), with emphasis on the quality and safety parameters in modified atmosphere packaging (MAP) and vacuum packaging (VP), were investigated. Quality assessment of mackerel stored in MAP (40% CO2+60% N2) and VP for up to 50 days at 4±1 °C was done by the monitoring of pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and histamine. The pH value of fish meat was significantly lower in the marinated samples. The highest concentration of TVB-N was recorded in the salted mackerel stored under VP whereas the lowest TVB-N in the marinated mackerel stored under MAP conditions. The formation of TBA increased with the time of storage and was the lowest in the marinated mackerel stored in MAP. The concentration of histamine increased during storage and its level reached over 10 mg/100 g for the salted mackerel stored under VP conditions. The marinated mackerel packed in MAP had extended shelf life at 4±1 °C compared to that packaged in VP according to physico-chemical analysis.

The scope and structure of the production and catch of fish in Serbia in the period from 2006. to 2012.

Fish represents a significant source of animal proteins in the diet of people in a large part of the world. The market in Serbia is supplied from its own production (carp and trout fish ponds) and catch from open waters. However, the largest part of the fish on the market is imported. Average area under carp fish ponds from 2006. to 2012. was 8,417 hektars, and under trout fish ponds was 49,900 square meters. Average annual production of carp fish species in this period was 7,228 tons, and of trout was 923 tons. In open waters of Serbia, the catch (from both professional and sport fishing) is averagely 3,745 tons of fish. The biggest catch of fish in open waters refers to goldfish, then carp and bream, while lower catch refers to white bighead. The objective of this investigation was to determine the scope and structure of fish catch and production in Serbia from 2006. to 2012. The data on fish catch and production were taken from Statistical Yearbook of the Republic of Serbia. [Projekat Ministarstva nauke Republike Srbije, br. TR 31011]