The influence of propolis and bee pollen on chicken meat quality

Across the world, as well as in Croatia, there is a continuous increase in the consumption of chicken meat, and attempts are being made in modern poultry production to improve its quality as much as possible by using various natural additives. The aim of this study was to determine the influence of dietary supplementation with propolis and bee pollen on the quality of chicken meat. In order to determine this effect, the carcass body weight of slaughtered chickens and carcass yield were determined, as well as the average pH1 and pH2 of chicken breast muscle, drip loss values, and skin color and chicken breast muscle color expressed as values of L* (lightness), a* (redness), and b* (yellowness). The study was conducted on 200 Ross 308 chickens, divided into five groups. Throughout the study, the control group of chickens was fed with a basal diet, while the experimental groups of chickens were fed with the basal diet supplemented with propolis and bee pollen, each supplement given separately or in combination in specific proportions. At the end of the experiment (42nd day), 10 chickens from each group were slaughtered for the analyses mentioned above. The carcass yield values were significantly higher (P = 0.038) and the drip loss values were significantly lower (P = 0.003) in the experimental groups in comparison to the control group. In addition, there was a statistically significant difference in b* skin color (P = 0.017) and b* chicken breast muscle color (P<0.001) between the groups of chickens. The study showed that dietary supplementation with propolis and bee pollen has a significant positive effect on the quality of chicken meat.

Quality and oxidative stability of eggs laid by hens fed marigold extract supplemented diet

The research objective was to determine the influence of marigold extract and storage duration on the indicators of egg quality and on the oxidative stability of eggs. The 5-wk long research was carried out on 300 laying hens. Laying hens were divided into control group (C-without marigold extract supplementation) and 2 experimental groups (E1-supplemented 1 g/kg of marigold extract and E2-supplemented 2 g/kg of marigold extract to diet). The eggs were analyzed on 2 occasions, as fresh eggs (1 D after collecting in the facility) and after 28 D of storage in a refrigerator on +4°C. On both occasions, there were 30 eggs analyzed per each group. Statistical analysis of the research results proved influence of marigold extract supplementation and storage duration on the weight of eggs (P < 0.05) and on the eggshell thickness (P < 0.001), but they did not have any influence on other indicators of external egg quality. Storage duration affected (P < 0.001) all indicators of internal egg quality, whereas supplementation of marigold extract influenced (P < 0.001) only the pH value of yolk. Supplementation of marigold extract influenced (P < 0.001) the yolk color intensity. There was a significant increase in the value of yolk color, starting with 9.63 in the C group and raising to 12.77 (E1) and 13.50 (E2) in fresh eggs. Yolk color of stored eggs was more intensive than the yolk color of fresh eggs in all 3 groups (P < 0.001). Supplemented marigold extract did not influence the obtained results of lipid oxidation in yolks, whereas storage duration had influence (P < 0.05) on oxidation intensity. The most favorable value of oxidation in fresh eggs was determined in the E2 group (0.545 μg MDA/g), and in stored eggs in the E1 group (0.615 μg MDA/g). Based on the research results, it was concluded that the supplementation of marigold extract had favorable influence on the yolk color intensity and on the oxidative stability of eggs without having negative influence on other egg quality indicators.

Distribution and age-related bioaccumulation of lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) in tissues of common carp (Cyprinus carpio) and European catfish (Sylurus glanis) from the Buško Blato reservoir (Bosnia and Herzegovina)

The purpose of this study was to quantify the bioaccumulation of Pb, Hg, Cd, and As in tissues of carp (Cyprinus carpio) and catfish (Silurus glanis) from Buško Blato in Bosnia and Herzegovina. Arsenic concentrations were below the Maximal Admissible Concentration (MAC) for Croatia and other countries. Mercury concentrations were below 1 mg kg(-1), but in most muscle samples of both species and all catfish liver samples, the values were higher than 0.5 mg kg(-1) (higher than the MAC for many countries including Croatia). Lead concentrations were higher than 1 mg kg(-1) (the MAC for Croatia) in most muscle samples; all kidney and most catfish liver samples also exceeded 1 mg kg(-1). Cadmium concentrations in all tissues, other than the gonads, were higher than 0.1 mg kg(-1) (MAC for Croatia), with the highest concentrations found in the kidneys. The only gender difference was found in carp, where a 68.4% higher concentration of As was found in the fry compared to the milt (P<0.05). Concentrations of all of the elements were higher in catfish compared to carp for most tissues. Significant correlations were found between all of the elements in the muscles and the liver of carp. In catfish, the muscles were the only tissue in which multiple correlations were found. Linear positive correlations with age and body mass were demonstrated for the concentrations of all heavy metals for all tissues except the gonads in both fish species. We concluded that significant heavy metal accumulation in carp and a catfish tissues correlates with age and body mass; bioaccumulation is species- and tissue-specific and is different for each element.