Zlata Kralik

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.

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.

Effect of Dietary Fat Sources on the Fatty Acid Composition and Sensory Characteristics of Chicken Meat

The research was carried out in two experiments on Ross 308 male hybrid chickens. Chickens were divided into five groups (five dietary treatments differing in source and concentration of plant oil and fish oil). Feeding chickens with diets of determined composition from 22nd to 42nd day of fattening resulted in altered fatty acid profile in white meat and dark meat, and in significantly lowered n-6/n-3 polyunsaturated fatty acids (PUFA) ratio in white meat. Increase of n-3 PUFA concentration in diets resulted in statistically significant (P = 0.001) increase of n-3 PUFA, as well as in decrease (P = 0.02) of n-6 PUFA in white and dark chicken meat in the 1st experiment. The 2nd experiment resulted in statistically significant increase of n-3 PUFA concentration in white and dark chicken meat (P 0.05). In order to produce chicken meat as functional product, it is possible to reach balance between high n-3 PUFA concentration and satisfactory sensory traits characteristics of chicken meat.

Effect of Amino Acids on Growth Performance, Carcass Characteristics, Meat Quality, and Carnosine Concentration in Broiler Chickens

The aim of this research was to investigate the deposition of carnosine in broiler muscles by feeding treatments comprising β-alanine, L-histidine, and magnesium oxide in various concentrations. The research was carried out on 120 Cobb 500 broilers divided into four groups. From weeks four to six, broilers were fed finisher mixtures as follows: P1, control group; P2, 0.5% β-alanine + 0.24% MgO; P3, 0.25% L-histidine + 0.24% MgO; and P4, 0.20% β-alanine + 0.10% L-histidine + 0.24% MgO. This paper presents the weights of broilers and their carcasses, portions of main parts of carcasses, technological quality of breast muscles, and concentrations of carnosine in breast and thigh muscles. The following traits of muscle tissue quality were measured: initial and final pH value (45 min after slaughtering pH1, and 24 h after cooling pH2), drip loss, color (Minolta colorimeter, expressed as CIE L*, CIE a*, and CIE b* values), meat softness, and cooking loss. Data on relative concentration of protein carbonyl (nmol/mg protein) in the muscles of breasts and thighs and levels of thiobarbituric acid-reactive substances (TBARS) in fresh and frozen breasts muscles (nmol/mg of tissue) are presented. Statistical analysis proved that feeding treatments had an effect on the live weight of broilers in the 4th, 5th, and 6th weeks of fattening (P<0.05), as well as on the carcass quality at slaughter (P<0.05; except the portion of wings), pH1 value (P=0.035), CIE a* indicator (P=0.007), drip loss (P=0.002), and meat texture (P=0.008). Compared to the control group, synthesis and deposition of carnosine were increased in breast muscles in groups P2, P3, and P4 by 7.51%, 10.62%, and 62.93%, respectively, and in thigh muscles by 61.05%, 78.95%, and 89.52%, respectively. It was also confirmed that feeding treatments influenced the level of TBARS in frozen broiler breast muscles (P=0.014).

Enrichment of table eggs with functional ingredients

The research was conducted on 120 laying hens of Tetra SL provenience, which were divided into two experimental groups (K and P), with 60 laying hens in each group (12 replications, 5 hens per replication). The control group was fed standard diet, while laying hens of experimental groups were given modified diet supplemented with 5% of oil mixture, 0.5 mg/kg organic selenium, 200 mg/kg lutein and 200 mg/kg vitamin E. Portion of n-3 PUFA was significantly better in designed eggs than in conventional eggs (3.76% and 1.69%, P<0.001). Ratio of n-6/n-3 PUFA in experimental group was more than twice as favorable as in the control group (5.91 vs. 13.34; P<0.001). Content of selenium, lutein and vitamin E in designed eggs was statistically significantly higher than in conventional eggs (P<0.001). The content of selenium in egg yolks in conventional eggs was 0.053 μg/g and in designed eggs 0.143 μg/g, and in egg whites 0.387 μg/g and 0.662 μg/g, respectively (P<0.001). Lutein content increased from 12.44 μg/g inconventional eggs to 104.95 μg/g in designed eggs, while vitamin E increased from 12.5 μg/g to 19.82 μg/g egg yolk.

Physical-Chemical Characteristics of Designer and Conventional Eggs

The objective of this study was to compare the internal and external quality of conventional and designer eggs. In total, 120 Tetra SL laying hens were randomly allotted to two treatments (K and P groups), with 12 replicates of five hens each. The control group (K) was fed a standard layer diet, producing conventional eggs, and the P group was fed a modified diet supplemented with 5% of an oil mixture, 0.5 mg organic selenium/kg, 200 mg lutein/kg and 200 mg vitamin E/kg, producing designer eggs. Treatments did not influence (p>0.05) egg weight or egg component weights. Designer eggs presented higher albumen proportion and lower eggshell proportion than conventional eggs (p<0.01). Relative to egg quality parameters, designer eggs presented higher HU values (83.99 vs. 80.81; p=0.042), more intense yolk color (14.38 vs. 8.70; p<0.01), and lower albumen pH (8.39 vs. 8.67; p=0.007). Feeding treatments and duration of egg storage did not significantly influence egg yolk lipid oxidation (p>0.05).

Omega-3 Polyunsaturated Fatty Acids Enriched Hen Eggs Consumption Enhances Microvascular Reactivity in Young Healthy Individuals

The beneficial effect of omega-3 polyunsaturated fatty acids (PUFA) supplementation on the cardiovascular (CV) system is well supported in CV patients; however, the effect of the consumption of omega-3 PUFA-enriched functional food in healthy individuals is still not fully elucidated. This study aimed to determine the effect of the consumption of omega-3 PUFA-enriched hen eggs on the microvascular reactivity (primary outcome), blood pressure (BP), and serum lipid profile in young healthy individuals. The control group (N = 16) ate 3 ordinary hen eggs (277 mg of omega-3 PUFAs/day), and the OMEGA-3 group (N = 20) ate 3 omega-3 PUFA-enriched eggs containing 259 mg of omega-3 PUFAs/egg daily (α-linolenic acid (ALA), 167 mg/egg; eicosapentaenoic acid (EPA), 7 mg/egg; docosahexaenoic acid (DHA), 84 mg/egg) for 3 weeks (777 mg of omega-3 PUFA/day). Postocclusive reactive hyperemia (PORH) in skin microcirculation assessed by laser Doppler flowmetry, serum lipid profile, fasting blood glucose, high-sensitivity C-reactive protein (hsCRP), and arterial BP were measured in all subjects before and after the protocol. PORH was significantly enhanced, and triglycerides, hsCRP, and BP were significantly decreased in the OMEGA-3 group compared with baseline measurements, whereas there was no significant difference in the control group after the protocol when compared with baseline. To the best of our knowledge, this is the first study to demonstrate that consumption of a mixture of omega-3 PUFA (ALA + EPA + DHA), provided via enriched hen eggs, elicits changes in the microvascular reactivity, BP, and triglyceride level in healthy subjects that are associated with CV benefits, thus suggesting that daily consumption of omega-3 PUFA-enriched eggs in healthy individuals may potentially contribute to CV risk factor attenuation and disease prevention.

The Effect of Feeding Laying Hen Conventional and Omega-3 Enriched Diet on Fatty Acid Profiles in Egg Yolk Lipids

The aim of this research was to enrich table eggs with n-3 polyunsaturated fatty acids (n-3 PUFA), especially with essential eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). After five weeks of feeding of laying hens with standard and experimental diets, there was analysis carried out to determine the fatty acid profile in egg yolks of both groups. Omega-3 eggs contain statistically significantly (P < 0.05) less sum of saturated fatty acids (ΣSFA) and more Σn-3 PUFA, as well as narrower ratio of Σn-6/Σn-3 PUFA than conventional eggs. If referring to individual fatty acids of omega-3 eggs, there were increased portions (P < 0.05) of α-linolenic acid (α-LNA), docosapentaenoic acid (DPA), EPA and DHA determined in this research, which was in line with the research objective. Within the presented research, concentration of n-3 PUFA in egg yolk lipids of experimental group was two times higher than that in the control group. The ratio of Σn-6 PUFA/Σn-3 PUFA was reduced from 12.04 to 6.17. Within their enzymatic system, laying hens can act as a bioreactor to naturally enrich their eggs with n-3 PUFA, especially with EPA and DHA. The results of this research proved that the fatty acid profile can be modified by designing of laying hens’ diets with specific forages. Eggs were enriched with favorable fatty acids in the following order: α-LNA > DHA > DPA > EPA.