Zlatko Janječić

The effect of MC4R polymorphism on carcass composition and meat quality traits in pigs slaughter at different live weights

Abstract Commercial crossbred pigs slaughtered at different live weights were used to investigate the effect of G1426A polymorphism in the melanocortin-4 receptor (MC4R) gene on carcass composition and meat quality traits. The significant effect of G/A substitution on backfat thickness (BF; P<0.01) was observed in pigs slaughtered at high live weight (123.0±6.5kg), but not in pigs slaughtered at low live weight (99.1±3.7kg). That was accompanied by tendency of decrease (P<0.10) in estimated lean meat percentage (LMP). The BF was higher and LMP was lower in AA compared to GG genotype (P<0.01). Meat quality traits were not affected by MC4R genotype. These results suggest that GG genotype could be favourable in pigs slaughtered at higher live weights due to lower BF and higher LMP.

Sensory profiling of Dalmatian dry-cured ham under different temperature conditions

Abstract To investigate the influence of the Dalmatian ham processing conditions on weight loss and sensory characteristics, 20 hams were processed following different temperature conditions during salting and ripening. For that purpose, hams were evaluated using quantitative descriptive analysis. The weight loss was higher and all sensory traits except presence of tyrosine and phenylalanine crystals were higher rated for hams processed at higher temperatures. The most significant (P<0.0001) influence of temperature was established on subcutaneous fat color, muscle color and presence of tyrosine and phenylalanine, whereas no influence was established on appearance, marbling, flavor and melting. This concludes that there is overall significant effect of higher temperature on sensory characteristics most likely due to the more intense proteolysis and lipolysis.

Immunomodulatory and antimicrobial effects of selected herbs on laying hens

The aim of the study was to investigate the efficiency of feed supplementation with dried calendula (C. officinalis), dandelion (T. officinale) and marigold (T. erecta) flowers, as well as dried basil (O. basilicum ‘Genovese’) leaves on the kinetics of the total leukocytes, helper and cytotoxic T lymphocytes, and B lymphocytes in peripheral blood, as well as on intestinal excretion of Escherichia coli in laying hens. Laying hens of Tetra SL line, aged 25 weeks, were used in the study. The animals were divided into nine groups of 15 birds. The laying hens were fed common feed with the addition of 1% (10 g/kg) and 3% (30 g/kg) chopped flowers or leaves of the above mentioned herbs. The immunomodulatory and antimicrobial effects of medicinal herbs in laying hens were estimated by the above mentioned parameters determined at the beginning of the experiment and on day 14 and day 28 of the study, i.e. at the birds’ ages of 25, 27 and 29 weeks. The study results showed that the addition of chopped calendula and dandelion flowers to laying hen feed stimulated proliferation of total leukocytes as well as T and B lymphocytes, particularly in the groups receiving 3% chopped herbs (P<0.01). All study herbs were found to have antimicrobial activity. The results obtained definitely confirm the favorable impact of adding herbs to hen feed because of their antimicrobial and immunostimulatory effects. Phytogenic feed additives exert favourable effects, however, knowledge of their use in poultry feed is still inadequate, thus requiring additional research. It was concluded that phytobiotics might be combined with other feed additives such as probiotics or prebiotics, in order to attain better results in poultry production.

Mechanical properties of ten-egg boxes made of different materials

This study was conducted to evaluate mechanical properties of ten-egg boxes, which are the most commonly used egg boxes in many countries of Central and South-Eastern Europe. Six ten-egg boxes were tested, two made of cardboard, two made of expanded polystyrene and two made of general purpose solid polystyrene, each from a different producer. There were no significant differences in basic dimensions between tested boxes of various materials, while the significant differences were occurred in weight and box wall thickness. Test included measuring of vertical forces required for deforming complete box and at particular place for each egg in a box till contact with eggs. According to the obtained results, cardboard boxes can provide the best mechanical protection for eggs. The average force required for deforming complete cardboard box was 83.6% higher than for solid polystyrene box, and even 289.5% higher than for expanded polystyrene box. The average force required for deforming cardboard box at particular place for each egg in a box was 60.8% higher than for polystyrene box, and 74.0% higher than for expanded polystyrene box. The disadvantage of cardboard boxes is that they are not resistant to the impact of moisture as polystyrene boxes and in the case of an increase in box moisture due to storage in inappropriate conditions their mechanical resistance decreases.

Some Physical, Morphological and Mechanical Characteristics of Turkey (Meleagris gallopavo) Eggs

The physical, morphological, and mechanical characteristics of eggs play an important role in the processes of embryo development and hatching. Some physical, morphological, and mechanical characteristics of turkey (Meleagris gallopavo; Zagorje breed) eggs collected during two laying cycles from same turkey hens were determined in this study. The average values of length, width, geometric mean diameter, weight, surface area, volume, sphericity, eggshell thickness, and eggshell density were determined as 66.61 mm, 46.84 mm, 52.66 mm, 77.74 g, 8712.42 mm2, 76553.49 mm3, 79.31%, 0.354 mm and 3.13 g cm-3, respectively. Eggs collected during second laying cycle were, on average, larger and heavier in comparison with those collected during first cycle. Average albumen, yolk and eggshell percentages of the eggs collected during two laying cycles were 58.11%, 29.50% and 12.39%, respectively. The highest breaking strength was obtained when the eggs were loaded along the X-front axis and the least breaking strength was required along the Z-axis. The average breaking strength, absorbed energy and firmness in loading along the X-front axis were found to be 73.80 N, 9.75 N mm and 280.30 N mm-1, respectively.