This study aimed to evaluate the dietary effect of organic sulfur (OS) supplementation on performance, egg quality and serum constituents in laying hens. A total of 360 Lohmann brown laying hens at the age of 31 weeks were distributed into four treatments having five replicates of 18 hens each until 54 weeks. The hens were fed four levels (0.0, 0.1, 0.2 and 0.4%) of OS with basal diet. The number of eggs was investigated daily, and egg quality was confirmed every 8 weeks. Sulfur content in eggs, interleukin 2 (IL-2), T help cells (CD4+) and cytotoxicity cells (CD8+) were measured at the termination of the experiment. The result of the study showed that egg production tended to increase with 0.4% OS in diet after 39 weeks of age and, there was a significant effect (P<0.05) from 47 to 54 weeks of age. Egg quality traits of albumen height and haugh unit increased significantly (P<0.05) owing to the addition of OS to the diet. The polyunsaturated fatty acids in yolk were gradually increased while saturated fatty acids were decreased with increasing levels in OS (P<0.05). Total sulfur concentration in the eggs increased significantly (P<0.05) in treatments fed OS. Moreover, albumin, AST and HDL cholesterol levels in serum improved significantly (P<0.05) owing to the addition of OS. The IL-2 concentration and the ratio of CD4+ and CD8+ in blood were generally higher (P<0.05) at 0.4% OS. Therefore, it can be recommended that supplementary OS diet affected the performance, egg quality and stimulated immune response in laying hens.

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As shown by Treloar, the degree of swelling of a rubber sample is strongly affected by applied stress. His work suggests that the degree of swelling will vary from point to point in a sample, in accordance with the local stress field. Thus, when rubber sheets are bent, they are expected to swell more on the tension side and less on the compression side, and when the bending constraint is removed, recovery toward the initial flat state is expected to be only partial at first and then followed by a slow further recovery. These effects are explored here for natural rubber sheets swollen by dodecane. The measured "set" following release from bending is found to be in accord with simple swelling theory. The time dependence of later recovery is shown to be in agreement with the rate of diffusion of the swelling liquid. It is concluded that internal migration of compatible liquids will cause temporary delays in deformation kinetics and make a significant contribution to energy losses. Also, the bending experiment itself appears to provide a simple and generally applicable method for determining the internal diffusion coefficients of absorbed liquids.

An experiment was conducted to investigate the effect of fermented garlic solution (FGS) on the performance, egg quality and blood profiles of laying hens in the finishing period. In total, 432 Lohmann Brown hens aged 79 weeks were equally distributed into four dietary treatments with six replicate. Hens were fed the basal diet containing 2,750 kcal/kg of ME and 16% of CP, which was supplemented with either 0% (control), 0.05%, 0.10% and 0.20% FGS from 79 to 83 weeks old. Laying performance, egg quality, yolk fatty acids and serum characteristics were analyzed at the end of experiment. Egg production and feed conversion was numerically improved in FGS supplementation treatments compared to those in the control, but were not statistically different. The albumen height and Haugh unit showed significant increase (P<0.05) in the FGS supplementation groups. The concentration of saturated fatty acid decreased in the yolks of birds fed FGS (P<0.01), whereas the unsaturated fatty acid (UFA) and mono-UFA contents were significantly higher (P<0.01) in those treatments than in the control. Significantly lower natural fat and cholesterol in serum were observed in birds fed the 0.20% FGS supplementation diet (P<0.01). However, the high-density lipoprotein (HDL) cholesterol increased in both the 0.10% and 0.20% FGS supplementation groups. In addition, interleukin-2 mRNA and CD4+/CD8+ level in serum which were cellular immunity indicators showed statistical differences (P<0.01) among treatments and a higher concentration in the 0.10% and 0.20% FGS groups than in the control. Thus, it can be concluded that dietary supplementation of FGS improved egg quality and stimulated immune response in mature laying hens.

This study was conducted to investigate the effect of feeding with dietary silicate based complex mineral (SCM) on the performance of laying hens. SCM at five levels (0%, 0.2%, 0.4%, 0.6% and 0.8%) was added to commercial diets, and fed to four hundred fifty Hy-Line Brown from fifty four to sixty five weeks of age. Egg production increased as the addition of dietary SCM to basal diets increased up to 0.6% (P<0.05). Furthermore, Feed intake increased in a manner similar to that of egg production (P<0.05). However, there was no difference in feed efficiency among the treatments. Eggshell thickness and breaking strength were significantly higher for the chickens fed with SCM than control from sixty weeks old to the end of experiment (P<0.05). Similarly, albumen height and Haugh unit were significantly higher for the chickens fed with SCM compared to those of control group (P<0.05). AST of birds fed SCM showed significantly higher than control (P<0.05). However, blood neutral fat level tended to increase in SCM treatments. Moreover, bone mineral density increased with SCM addition up to 0.4% (P<0.05). IL-2 (Interleukin-2) and IL-6 (Interleukin-6) levels appeared to be improved in the chickens fed with SCM addition diets, although not statistically different from all treatments. The results of this study indicated that the optimum SCM for improving the performance, egg quality and immunological competence of laying hens from 54 to 65 weeks of age was 0.6%.(Key words: egg quality, immunological competence, laying hens, performance, silicate complex mineral) † To whom correspondence should be addressed : seon@jbnu.ac.kr 서 론 국내에서 주요 광물질에 속하는 규산염계 복합광물질은 널리 분포되어 있으며, 표면에 친수성 미세구멍이 다량 존재 하여 흡착력이 강하므로 산업적으로 토질개량과 이온교환 장치 등으로 광범위하게 이용되어 왔으며, 축산업에서는 이 러한 규산염 계통 이외에도 제오라이트(zeolite), 벤토나이트 (bentonite), 고령토(kaolin) 및 흑운모(biotite) 등을 활용하여 항생제를 대체하는 사료첨가제로 연구하여 왔다 (Safaeikatouli et al., 2011;Melegy et al., 2015;Yenice et al., 2015).