Published in Scientific Papers. Series D. Animal Science, Vol. LXIII, Issue 2
Written by Cristina Gabriela RADU-RUSU, Ioan Mircea POP, Raluca Elena DONOSA, Daniel SIMEANU
Several nutritional approaches were used to warrant the quality and safety of hen table eggs throughout the last decades. Apart from most of the researches focusing on the usage of a wide variety of minerals sources in layers’ nutrition, this study aimed to measure the effect of using six different feed additives on the eggs quality, hypothesizing in the beginning on the indirect effects that they might induce in hens’ minerals metabolism, in electrolytic homeostasis or in improving the digestive organs capacity to uptake minerals form diet and to transfer them in egg structure. Seven groups comprising each 120 ISA Brown layers, aged 30 weeks, were formed and fed a conventional diet for peak of production at a daily intake of 120 g mashed feed (2750 Kcal/kg metabolizable energy, 17.5% crude protein). Control group (CG) received plain diet, without additives, while the other groups received different rates of additives supplementation: 0.03 % ascorbic acid (ASC group); 1% sodium bicarbonate (SOB group); 0.3% prebiotics as organic acids mixture (OAC group); 0.1% mannan oligosaccharide prebiotic (MOS group); 0.1% synbiotic mixture-probiotic, prebiotic and phytogenic compounds (SYN group); 0.2 % mycotoxins adsorbent (MYC group). The reasoning criteria were represented by: eggs structure (% of edible and non-edible parts); Haugh Index (HU) as freshness trait; eggshell integrity (% of whole eggs yield); eggshell defects and commercial loss (% of whole eggs yield); shell thickness (mm); shell breaking strength (Newton). All analyses were run for one-week eggs yield, using 280 eggs randomly collected from each group (40 eggs per day). Eggs structure varied between 25.17%-25.73% yolk proportion, 64.47-65.00% albumen proportion and 9.34-9.89% shell proportion, with certain levels of statistical significance between tested groups, in terms of shell participation in whole eggs structure. Haugh Index assessment indicated not significant improvement or decrease of freshness and commercial status of the eggs due to feed additives supplementation (88.33-90.38 H.U., commercial class AA). Usage of certain feed additives, such as prebiotics, probiotics, synbiotic and mycotoxins adsorbents significantly improved shell thickness, by 9.94 to 14.04% (P < 0.05), while ascorbic acid and sodium bicarbonate usage slightly but not significantly improved the same trait (3.80-4.39%). The most improved integrity trait was the shell breaking strength, subsequently to shell thickness increasing. Thus, it significantly differed versus control (P<0.05, 4.19-5.08% better resistance in ascorbic acid and sodium bicarbonate supplementation) and distinguished significantly (P<0.01, 10.3 to 14.2% improved). Overall, commercial loss due to shell quality issues decreased from 8.9% of whole yield to 5.0-6.8% in the hen groups whose diet was supplemented with studied experimental factors.
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