Effect of organic and nano copper supplementation on performance, egg quality, yolk cholesterol and blood parameters of laying hens

Introduction: The efficacy of the use of microelements is an important issue in modern poultry nutrition. Microelements are essential for normal growth and many metabolic processes in living organisms, as they are catalysts or constituents of the enzymatic systems of many cells. These facts, along with advanced knowledge of the importance of microelements in immunological processes and reproduction and the variable content of trace minerals in feed materials, has lead, in commercial practice, to their being added to poultry diets in high amounts, with a large safety margin, often exceeding the birds’ requirements. This can lead to a high concentration of microelements in animals’ excreta and their accumulation in the environment, especially in areas of intensive poultry production (Swiatkiewicz et al. 2014). The nanoparticle, which is at least one dimension reduced to a Nano metric size, exhibits new electrical, magnetic, mechanical, and biological properties, which have been determined as critical factors influencing particle uptake. Therefore, the new phenomena and properties of nanoparticles may have unique potential applications. Pekel and Alp (2011) stated that supplementation with 250 mg/kg of copper decreased blood GSH-Px levels and that this could cause a reduction in tissue cholesterol concentrations. Jegede et al (2015) reported that cholesterol content in the yolk of laying hens egg was reduced in birds fed with 150 mg kg-1 Copper proteinate.
Material and methods: The experiment included 5 dietary treatments, which consisted of a basal diet, the basal diet with 75 or 150 mg/kg of Cu from organig source (Bioplex, Alltech Inc., Nicholasville, KY) and the basal diet with 75 or 150 mg/kg of Cu from nano (Framelco, The Netherlands). The hens were allocated in individual cages (41×23×43 cm) and two cages were considered to one replicate. Before starting the experiment, the live weights and egg production of all birds were recorded and distributed to all cages in similar weight and equal egg production. The lighting schedule was a 16 h light/8 h dark cycle with an average light intensity of 15 lx, which was maintained until the end of the experiment, and fresh water) were provided ad libitum throughout the experiment. At the beginning of this experiment fed on a balanced commercial layer diet two weeks prior to study to allow them to adapt and reach a standard level of egg production (data not shown). The data were analyzed based on a completely randomized design using general linear model procedure of SAS (version 8.0; SAS Institute, Cary, USA). When treatment means were significant (p< 0.05), the Duncan multiple range test was used to compare the means.
Results and discussion: Feed intake was not affected by dietary treatments (P >0.05). Different levels of dietary treatments increased egg production compared to the control group (P <0.01). Birds fed diet with 150 mg/kg bioplex and nano copper has a significantly lower feed conversion ratio than control diet (P <0.05). The use of different sources and levels of copper had no significant effect on the quality traits of eggs (P<0.05). All dietary treatments resulted in a significant decrease in cholesterol of yolk (P<0.01) or plasma (P<0.05). Also, the biochemical parameters of plasma were not significantly influenced by the addition of different levels of copper to the diet (P >0.05). Lim and Paik (2006) reported a variable effect of organic Cu on the egg production and egg quality. In the present study, the results showed that the addition of organic and nano copper increased egg mass and production, these results are consistent with Tanika (2004) findings. Eggs are rich source of dietary cholesterol and consumption of high level of dietary cholesterol increases the risk of coronary heart disease (Kritchevsky 2004). Based on the results a significant reduction in egg yolk cholesterol of laying birds fed supplemental copper was seen. These findings are in agreement with previous studies in copper-supplemented birds (Leeson 2004). The significant reduction in yolk cholesterol by feeding copper Bioplex and nano copper shows that organic and nano forms of copper were more effective in reducing cholesterol level when fed to laying birds. This observation agreed with the report of Idowu et al. (2006).
Conclusions: It was concluded that dietary supplementation of 150 mg/kg nano copper and bioplex significantly increased hen day egg production. The cholesterol content in the yolk and plasma of laying hens was reduced in birds fed dietary treatment.