Effects of glycerol on performance, egg traits, some blood parameters and antibody production to SRBC of laying hens Sakine Yalçın a, ⁎, Handan Erol b , Bülent Özsoy c , İlyas Onbaşılar d , Suzan Yalçın e , Aykut Üner f a Ankara University, Faculty of Veterinary Medicine, Department of Animal Nutrition, Ankara, Turkey b Abant İzzet Baysal University, Mudurnu Vocational School of Higher Education, Bolu, Turkey c Mustafa Kemal University, Faculty of Veterinary Medicine, Department of Animal Nutrition, Hatay, Turkey d Hacettepe University, Faculty of Medicine, Laboratory Animal Husbandry and Research Unit, Ankara, Turkey e Selçuk University, Faculty of Veterinary Medicine, Department of Food Hygiene and Technology, Konya, Turkey f Adnan Menderes University, Faculty of Veterinary Medicine, Department of Physiology, Aydın, Turkey article info abstract Article history: Received 11 June 2009 Received in revised form 19 October 2009 Accepted 21 January 2010 This study was designed to investigate the effects of the usage of glycerol from biodiesel production from soybean oil in laying hen diets on laying performance, egg traits, heterophils to lymphocytes ratio (H/L), some blood parameters and antibody production to SRBC. A total of 180 Lohmann Brown laying hens 39 weeks of age were allocated to four dietary treatments with one control group and three treatment groups and fed for 16 weeks. Each group was divided into five replicates as subgroups, comprising of 9 hens each. Glycerol was used at the level of 2.5, 5 and 7.5% in the diets of the first, second and third treatment groups, respectively. The diets were formulated to be isocaloric and isonitrogenous. Dietary treatments did not significantly affect body weight, egg production, egg weight, feed efficiency, mortality, egg albumen index, egg yolk index and egg Haugh unit, yolk weight percentage, exterior egg quality characteristics, excreta moisture, H/L ratio, blood parameters and antibody production to SRBC. Hens fed diets with 7.5% glycerol consumed significantly less feed than those of the other groups. Egg yolk cholesterol concentration was significantly higher for hens fed diets with 5 and 7.5% glycerol as compared to those of the other groups (P < 0.01). The ratio of monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) in eggs was decreased (P < 0.01) with dietary glycerol supplementation. The inclusion of glycerol had no significant effects on blood parameters, H/L ratio, antibody titers to SRBC and excreta moisture. It is concluded that glycerol can be used at 2.5% in the diets of laying hens without adverse effects on the measured parameters. Dietary glycerol at the levels of 5 and 7.5% increased egg yolk cholesterol and decreased the ratio of MUFA/SFA without affecting performance, other egg traits, immune response, H/L ratio, blood parameters and excreta moisture. © 2010 Elsevier B.V. All rights reserved. Keywords: Glycerol Laying hen Performance Egg traits Blood parameters 1. Introduction Biodiesel, a mixture of methyl esters of fatty acids, is an alternative diesel fuel that is produced by chemically reacting a vegetable oil or animal fat with an alcohol, usually methanol. As a by-product 1 mol of glycerol is produced for every 3 mol of methyl esters, which is equivalent to approximately 10% of the total product (Karinen and Krause, 2006). Chemically pure glycerol is a valuable industrial compound for use in many applications including food and consumer products such as cosmetics and pharmaceuticals. Recently crude glycerol may become available for use as livestock feed. Some studies on glycerol for broilers (Simon et al., 1996; Cerrate et al., 2006), turkey hens (Rosebrough et al., 1980) and pigs (Kijora et al., 1995) have shown that glycerol from biodiesel production can Livestock Science 129 (2010) 129–134 ⁎ Corresponding author. Ankara University, Faculty of Veterinary Medicine, Department of Animal Nutrition, 06110 Dışkapı, Ankara, Turkey. Tel.: +90 312 3170315; fax: +90 312 3181758. E-mail address: yalcin@veterinary.ankara.edu.tr (S. Yalçın). 1871-1413/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2010.01.014 Contents lists available at ScienceDirect Livestock Science journal homepage: www.elsevier.com/locate/livsci