Natasa Glamoclija

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.

Relationships among pre-slaughter stress, rigor mortis, blood lactate, and meat and carcass quality in pigs

Abstract The aim of this study was to examine the relationships among pre-slaughter stress, rigor mortis, blood lactate, and meat and carcass quality in 100 pigs (cross between Naima sows and hybrids P-76 PenArLan boars). Before slaughter lairage time, handling and pig behavior were assessed for each animal. At exsanguination blood concentrations of lactate and cortisol were determined, while post-mortem were assessed: initial and ultimate pH value, temperature, drip, sensory and instrumental colour and marbling. On the carcasses the degree of rigor mortis and skin damage score were estimated, as well as carcass quality parameters. More developed (p<0.01) rigor mortis was observed after long lairage compared to short lairage. Higher intensity of rigor was found in pigs with higher blood lactate level (p<0.05) and with a greater thickness of subcutaneous fat tissue (p<0.05) and lower lean meat content (p<0.01). Higher blood lactate level was observed after long lairage compared to short (p<0.05) and after rough handling compared to gentle handling (p<0.01). In the group with blood lactate from 10 to 15 mmol/l meat temperature and skin blemishes score increased, while in the group with the highest blood lactate concentration (>15 mmol/l) initial pH decreased and L* value increased. These results suggest that in groups with higher blood lactate concentrations meat quality deteriorates.

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.

Analysis of poultry meat production volume in Serbia from 1984 to 2009.

Poultry meat production has doubled in past 40 years in the world, with the tendency of constant growth, and its production volume exceeds beef, but is behind pork production. For poultry meat production it is typical that its annual increase exceeds pork as well as beef production. The biggest producers of poultry meat are Asia, North and South America and Europe. The most significant category of poultry is meat of young chicken (broilers). Cobb, Ross and Hubbard broiler provenance are most common in Serbia. The objective of this investigation was to analyse poultry meat production volume in Serbia, observed during three six-years periods - A (1984-1989), B (1994-1999) i C (2004-2009). For data processing there were used the data obtained from Statistical Yearbooks of Serbia from 1984. to 2009. It was found out that average poultry meat production in period A was 108,33 ± 7,00 thousand tonnes, than it statistically significantly decreased and in period B it was 76,67±5,54 thousand tonnes, and finally in period C it was 72,17± 5,78 thousand tonnes. [Projekat Ministarstva nauke Republike Srbije, br. TR 31034]

Assessment of welfare conditions during stunning of pigs with respect to the day of the week.

Proper stunning is important in order to ensure animal welfare and to improve meat quality. The conditions in which the stunning is performed and the result of procedure may vary in practice due to numerous factors. The aim of this study was to examine the effectiveness of the stunning procedure with respect to the day of the week. The experiment was conducted on 100 pigs of different genetic origin and of different age and live weight during 5 working days (20 pigs per day). Stunning procedure was assessed through the following parameters: placing of electrodes at the proper position on the head; application of energized electrodes; voltage, amperage and frequency of the current; duration of current application and interval from stunning to bleeding; presence of tonic, clonic convulsions, as well as rhythmic breathing and re-stunning. In this study, improper electrode placement was observed in 40-70% of pigs, application of energized electrodes in 5-45% of pigs, duration of current application from 6,90 to 17,55 seconds, and the interval from stunning to bleeding from 48,62 to 91,25 seconds, the presence of tonic and clonic convulsions, and rhythmic breathing in 65-85%, 45-75% and 10- 75% of pigs. The stunning procedure was repeated in 5-15% of pigs. In addition, the deterioration of most of the parameters at the end of the week was observed. These results suggest unsuccessful stunning of pigs as a consequence of insufficient staff training, and their fatigue at the end of the week. .