Gordana Kralik

Effects of organic selenium supplemented to layer diet on table egg freshness and selenium content

Abstract The aim of the research was to determine the effects that organic selenium supplemented in layer diets has on its content in the edible part of egg, on egg freshness and activity of glutathione peroxidase (GSH-Px) in hens’ blood. The experiment lasted for 30 days and was completed on 240 laying hens of the Hy Line Brown hybrid. Hens were divided into 2 experimental groups (E1 and E2), each consisting of 120 hens housed in 24 cages. Hens were fed a commercial diet containing 18% of crude protein and 11.60MJ ME/kg. The experiment was set up in two different feeding treatments. The E1 group had diets supplemented with 0.2ppm of selenium, and E2 had diets with 0.4ppm of selenium (organic selenium Sel-Plex®, Alltech, inc.). The GSH-Px activity was higher in blood of hens in the E2 group than in the E1 (P<0.05). Furthermore, statistically the E2 group had a significantly higher portion of selenium in egg yolks and albumen than the E1 group (P<0.05). Analysis of effects that feeding treatments have on egg freshness over three examined periods (fresh eggs, eggs stored for 14 and for 28 days at 4ºC) showed better results for HU (Haugh units) and TBARS (thiobarbituric acid reactive substances) in the E2 eggs than in the E1 eggs.

The effect of different oil supplementations on laying performance and fatty acid composition of egg yolk

Abstract The aim of the research was to determine effects of different combinations of rapeseed and fish oil - instead of soybean oil - on the performance of laying hens and on the profile of fatty acids in egg yolks, especially on n-3 polyunsaturated fatty acid (PUFA), when such oils are added to the diet of laying hens. The research was carried out on 90 laying hens of the Hy-Line hybrid ranging in age from 32 to 36 weeks old. Hens were divided into three groups (30 laying hens per groups) and fed with a commercial mixture that contained 17% of crude protein and 11.6 MJ ME. The research lasted for 28 days. The control group (C) was given diets with soybean oil supplemented in the amount of 5%, and experimental groups (E1 and E2) were fed diets that contained a combination of fish and rapeseed oils in different amounts. Diets given to the E1 group contained 3.5% of fish oil and 1.5% of rapeseed oil, while the E2 group was fed diets with 1.5% of fish oil and 3.5% of rapeseed oil. Production characteristics of hens were monitored during the whole experiment. Portion of saturated (SFA) and unsaturated fatty acids (MUFA and PUFA), as well as α-linolenic (αLNA, C:18:3n-3) eicosapentaenoic (EPA, C20:5n-3) and docosahexaenoic (DHA, C22:6n-3) acid were shown as a percentage of total fatty acids contained in yolk. There were statistically significant differences (P<0.05) only in the hens’ end weights and laying intensity between the C and E1 group, as well as between the C and E2 group. The portion of SFA in total fatty acids contained in yolk was not statistically significant (P>0.05) among investigated groups. Higher content of MUFA was noticed in both experimental groups, if compared to the control (E1 41.37%: E2 40.72%, C 36.95%, P<0.05). Content of αLNA differed significantly (P<0.001) between E1 and the control group, and the content of DHA differed significantly (P<0.001) between E1 and the control group, as well as between E2 and the control group. Total n-3 PUFA was increased in the E1 group for 2.10, and in the E2 group for 1.41 times than in the control group. The ratio of n-6/n-3 PUFA was the lowest (P<0.05) in egg yolks of the E1 group (4.01), followed by that of the E2 group (6.56), and finally that of the control group (11.08).

Differentiation of pork longissimus dorsi muscle regarding the variation in water holding capacity and correlated traits

Abstract This study was performed on 87 randomly selected carcasses of castrated pigs, slaughtered at approximately 100 kg live weight in 2 abattoirs from east Croatia. Important meat quality traits were measured on the samples of musculus longissimus dorsi: initial and ultimate pH values (pH45 and pH24), meat colour and drip loss. Samples were further differentiated into 5 groups on the base of meat quality conditions. Results show that 14.66%, 32%, 40%, 10.67% and 2.66% of the longissimus dorsi muscles belonged to PSE, RSE, RFN, PFN and DFD conditions respectively. The highest correlations were observed between ultimate pH value, drip loss and meat colour. Interpolated threshold value for ultimate pH was 5.69. It is suggested to verify the values used for differentiation of meat according to quality on a larger sample.

Determination of anti-oxidative histidine dipeptides in poultry by microchip capillary electrophoresis with contactless conductivity detection

A home-made microchip electrophoresis (MCE) device was used to quantitate two biologically important histidine dipeptides, carnosine and anserine, using capacitively coupled contactless conductivity detection (C4D), at pH 2.7. The C4D detector exhibited a linear response to both carnosine and anserine in the range of 0-200μM for the individual dipeptides and in the range of 0-100μM for each dipeptide when both were present as a mixture. The limit of detections (LOD) for the dipeptides in the mixture were 0.10μM for carnosine and 0.16μM for anserine. Standard addition was used to detemine the accuracy of the method. For carnosine and anserine the recoveries were in the range of 96.7±4.9-106.0±7.5% and 95.3±4.5-105.0±5.1% in thigh muscle and 97.5±5.1-105.0±7.5% and 95.3±5.4-97.3±5.6% in breast muscle, respectively.

Harmonization of welfare standards for the protection of pigs with the EU rules: the case of Croatia

Abstract Three quarters of Croatian pigs are produced in small production units (1-5 sows) and on family farms with mixed farming activities. Only few farms have specialized production units with up-to-date technologies and comply with EU standards. The future competitiveness of Croatian pig production is therefore questionable unless production systems are changing. Modernisation will most probably result in the expansion and intensification of larger farms and the termination of a great number of small farms. The aim of this study was to investigate how the welfare of pigs on Croatian farms would be affected by modernisation. Seventeen Croatian pig farmers were interviewed to describe the different pig production systems, while the welfare of pigs was assessed using resource-based and animal-based welfare indicators. Three production systems were distinguished: part-time family farms (PFF), full-time family farms (FFF) and farm enterprises (FE). Resources-based welfare indicators were investigated in 17 pens located on seven PFF, 25 pens distributed across six FFF and seven pens were visited at two FE. Animal-based welfare indicators were assessed on 21 pigs at PFF, 90 pigs at FFF and 18 pigs at FE. The study demonstrated that different production systems have different welfare problems. Based on resource-based indicators pig welfare was better ensured on FE, but based on animal-based indicators there was no clear difference in welfare between the three production systems. Based on these findings is it unlikely that the modernisation of current production systems in Croatia will significantly improve pig welfare. From a welfare point of view, neither the enlargement nor the termination of pig farms can be supported. However, the number of farms involved in this study was too small to allow for generalisation. The case-study does, however, point at the importance of further studies into the specific welfare problems of each of the production-systems and their different solutions. These studies should be of larger scale in order to get a representative picture of pig welfare in Croatia, and its assurance within the process of modernisation.

A simple DNA based method for determination of pure Black Slavonian pigs

Abstract The aim of this work was to determine the MC1R genotype of Black Slavonian pigs and to find an efficient and simple PCR-RFLP method, based on differences in MC1R genotype, to distinguish between purebred Black Slavonian pigs and their crossings with commercial pig breeds and Wild Boars. Sequencing of the MC1R exon was performed to determine the genotype of MC1R in Black Slavonian pig breed, which was shown to be MC1R*2. Digestion reactions of both PCR products representing the majority of MC1R exon revealed presence of the BspHI restriction site at position 121 and absence of the AccII and CrfI restriction site at position 240, which is characteristic for the MC1R*2 genotype. A simple PCR-RFLP method, based on different coat colour MC1R gene genotypes was determined by which it is possible to detect potential crossings of autochthonous Black Slavonian pig with commercial pig breeds and also with Wild Boars.

Beneficial effects of different dietary oils on cholesterol level and fatty acids profile of turkey pectoral muscle

Abstract Human health depends to a great extent on the quality of consumed food. The relationship between the diet and health is increasingly evident. Therefore, the exact food composition, as well as the possibilities of its improvement, is intensively investigated. Turkey pectoral muscle is often recommended today as the most healthy meat product. The aim of our study was to improve the pectoral fat content of turkeys by adding some extra fat sources to their meals. The study was performed on 90 female turkeys of the hybrid Nicholas 700, in their final fattening period (from 15th to 19th week of age). Turkeys were divided into three groups, each represented by 30 individuals, and fed with meals differing in fat source, in the amount of 3% of the total meal weight. The added fat in the first group came from the commercial preparation Bergafat. Pronova Biocare Epax 3000 TG was added to the food of second group, while the third group had rapeseed oil added. After the fattening period, the quality of pectoral muscle was determined for the 10 carcasses from each experimental group (water holding capacity - WHC, meat color, protein, fat, ash, water, cholesterol and fatty acids content). Meat color did not differ between the investigated groups, while WHC statistically differed (P<0.05). Turkey muscles in the first group had the best WHC (7.76 cm2), while the the second group had the worst (9.12 cm2). No difference could be shown in the turkey muscle protein, water and ash content between the experimental groups. However, the second experimental group had a lower total lipid content (1.73%, P<0.05) compared to the first (1.97%) and third (1.93%). Turkeys from the first and second groups had lower cholesterol concentration in the pectoral muscle lipids (21.74 and 18.04 mg/100g, respectively, P<0.05) compared to the third group (41.00 mg/100g). The second experimental group had the highest PUFA content (P<0.001) and lowest n-6/n-3 ratio (P<0.001) compared to the other experimental groups. We concluded that the most favourable effects on the lipid status of turkey pectoral muscle was observed with the Pronova preparation, which lowered its total lipid and cholesterol concentration, raised PUFA content, and lowered the n-6/n-3 ratio. Further investigations, including combinations of added oils to the diet, should be directed to minimize the observed undesirable effects of Pronova preparation on turkey meat quality characteristics.

Application of growth functions in the prediction of live weight of domestic animals

We consider several most frequently used growth functions with the aim of predicting live weight of domestic animals. Special attention is paid to the possibility of estimating well the saturation level of animal weight and defining life cycle phases based on animal weight. Parameters of the growth function are most often estimated on the basis of measurement data by applying the least squares (LS) principle. These nonlinear optimization problems very often refer to a numerically very demanding and unstable process. In practice, it is also possible that among the data there might appear several measurement errors or poor measurement samples. Such data might lead not only to unreliable, but very often to wrong conclusions. The least absolute deviations (LAD) principle can be successfully applied for the purpose of detecting and minorizing the effect of such data. On the other hand, by using known properties of LAD-approximation it is possible to significantly simplify the minimizing functional, by which parameters of the growth function are estimated. Implementation of two such possibilities is shown in terms of methodology.

A mathematical model of controlling the growth of tissue in pigs

A mathematical model of controlling the growth of tissues in pigs is described in this paper. In that sense, a method is given by which it is possible to periodically and very accurately estimate live pig weight of backfat based upon measurements done by ultrasound. These estimations will be used for the purpose of predicting growth of backfat in live pigs. Backfat weight is estimated on the basis of measurements done by using the Moving Total Least Squares Method, whereas estimation of live pig backfat growth is done by using a generalized logistic function, whose parameters are estimated by means of the Least Squares Method. Since thereby the Hessian of the corresponding minimizing function is very close to a singular matrix, an additional problem analysis was necessary.

The Effect of Dietary Intake of Omega-3 Polyunsaturated Fatty Acids on Cardiovascular Health: Revealing Potentials of Functional Food

Functional food is a food containing components that show beneficial effects on one or more body functions and improve general condition and health or significantly affect lowering of disease risks. This chapter is aimed to examine the effect of dietary intake of omega‐3 polyunsaturated fatty acids (n3‐PUFA) on cardiovascular health. This chapter presents current knowledge on functional poultry products and the reasons to consume them, omega‐3 enrichment of eggs and poultry meat, and the differences in profile of fatty acids in conventional and omega‐3–enriched eggs. The second part of the chapter focuses on the metabolism of fatty acids and effectiveness of n‐3 PUFA in the improvement of endothelial function, improvement of elasticity of the vascular wall and the anti‐inflammatory effects in patients with chronic diseases, such as metabolic syndrome, diabetes mellitus and hypercholesterolemia, and overall effect on cardiovascular health and protection. To achieve long‐term protective effects, the functional food should be consumed on daily basis. There are no specific constrains in taking functional food ; even more, it can be recommended to athletes and cardiovascular patients. General population can also benefit from eating functional food enriched with n‐3 PUFA due to their anti‐inflammatory and vascular‐protective effects.