The effect of dietary Rhus coriaria L . on table eggs yolk nutrients composition

© Slovak University of Agriculture in Nitra Faculty of Agriobiology and Food Resources, 2014 http://www.fapz.uniag.sk/ DOI: 10.15414/afz.2014.17.03.93–95


Introduction
Phytogenic feed additives are used in animal nutrition and feeding for their beneficial effects such as higher performance, reproduction and health status (Capcarová and Kolesárová, 2010).Phytogenics are feed additives, plant-derived products used in animal feeding to improve the performance of livestock.Most studies investigate blends of various active compounds and report the effects on production performance rather than the physiological effects (Windisch et al., 2008).The last two decades have seen a substantial increase in the use of aromatic herbs and essential oils as feed additives in animal nutrition (Franz et al., 2010).Positive effect of phytoadditives are determine by application dosage and additive composition (Gálik et al., 2013), they are usable in animal nutrition for better feed conversion ratio and nutrient utilization (Kroismayr et al., 2007 andLi et al., 2007).In laying hens nutrition, feed additives can improve their production and also nutrient composition of eggs, mainly yolk nutrients content.The aim of the study was to analyse the dietary effect of Rhus coriaria L. seeds as a phytogenic additive on yolk nutrient composition in Hy-Line Brown laying hens nutrition.

Material and Methods
The experiment was realised in cooperation with the Selecta), content of crude fat by Soxhlett-Henkel method (apparatus Soxtec, Tecator) and content of cholesterol by photometrical method (wavelength 546 nm, apparatus UV-VIS Helios, Thermo Spectronic) were analysed.
To calculate basic statistic characteristics, to determine significance of differences and to compare results the analysis of variance, one-way ANOVA and t-test were performed at P <0.05.Results are show as mean±S.D.The SAS statistical software was used (SAS Inc., New York City, U.S.A.).

Results and Discussion
There are many papers, which focused on different feed additives for poultry as an alternative for antibiotic growth promoters (Cross et al., 2007;Gálik et al., 2013).Plant extracts, or their ethereal oils are typical for many desirable effects, such as inhibition of pathogen microorganism and stimulation of same desirable physiological processes (Gali-Muhtasib et al., 2006;Yazan et al., 2009).In our experiment we analyzed the effect of a phytogenic additive Rhus coriaria L. on yolk nutrient composition during 21 weeks.During the trial, the eggs were analysed three times, every 7 weeks after the experiment start.Results are show in Table 2.We found insignificant (P >0.05) differences in dry matter content in egg´s yolks.In crude protein of egg´s yolk in 1 st and 2 nd collection we found a tendency (P >0.05) of higher content in eggs of hens fed with Rhus coriaria L. supplementation in feed mixture.Significant differences (P <0.05) were found in yolk crude fat content.After phytogenic additive (seeds of Rhus coriaria L.) we found significantly lower crude fat content in all collection, mainly in second eggs collection (628.43 g kg -1 of dry matter in control group vs. 590.37g kg -1 of dry matter in experimental group).Our results correspond with results published by Arpášová et al. (2010).Authors reported that major effect of a phytogenic additive in hens nutrition is an decrease of crude fat in egg´s yolk.Important factor of phytogenic additive is decreasing of cholesterol in yolk of eggs (Islam et al., 2011;Gálik, 2012).In cholesterol content of egg´s yolk we found significantly lower value (P <0.05) in experimental group (11.65 mg kg -1 of yolk) in comparison to control group (12.56 mg kg -1 of yolk) in first collection.After 7 weeks of first collection we found a tendency (P >0.05) of lower cholesterol content in yolks from experimental group of hens.After next 7 weeks (3 rd eggs collection) we analyzed in eggs of hens from experimental group (control diet) significantly (P <0.05) higher cholesterol content (13.29 mg kg -1 of yolk) in comparison to experimental group (Rhus coriaria L. supplementation), 11.57mg kg -1 of yolk.

Conclusions
In our experiment we found a positive effect of Rhus coriaria L. supplementation in laying hen's total feed mixture on qualitative parameters of table eggs production.After supplementation of the additive we found significant (P <0.05) differences in crude fat and

The effect of dietary Rhus coriaria L. on table eggs yolk nutrients composition
Branislav Gálik*, HenrietaArpášová, Daniel Bíro, Michal Rolinec,  Milan Šimko, Miroslav Juráček, Róbert HerkeľSlovak University of Agriculture in Nitra, Slovak RepublicThe aim of the study was to analyze the effect of Rhus coriaria L. supplementation in total feed mixture on yolk nutrients composition of laying hens Hy-Line Brown.Hens at 20 weeks of age were randomly divided to two groups (10 hens per group); control group was fed by standard total feed mixture and experimental group was fed by standard feed mixture supplemented with Rhus coriaria L. seeds (dosage 1 % in feed mixture).Experiment lasted 21 weeks.During the experiment the eggs were collected 3 times (every 7 weeks after the beginning).After Rhus coriaria L. supplementation a tendency (P >0.05) of higher crude protein content in yolks from experimental group of hens was found, significant (P <0.05) differences were found in 3 rd collection.Rhus coriaria L. addition in total feed mixture significantly (P <0.05) decrease content of crude fat in egg´s yolk, mainly in 2 rd collection (628.43 in control vs. 590.37g kg -1 of dry matter in experimental group).Positive effect of analyzed phytogenic additive was found in cholesterol content in egg´s yolk.Significant (P <0.05) lower content of cholesterol in yolk was found after 1 st eggs collection (12.56 in control group vs. 11.65 mg kg -1 of yolk) and after 3 rd collection (13.29 in control group vs. 11.57mg kg -1 of yolk in experimental group).Rhus coriaria L. seed supplementation in the diet of laying hens had positive effect on nutrients composition of table egg´s yolk.

Table 1
Nutritive value of feed mixtures in the trial

Table 2
Composition of yolk during the trial (mean ±S.D.)