Judul: Pengaruh Suplementasi Vitamin E dan Selenium dalam Ransum terhadap Performa Ayam Petelur Umur 46-51 Minggu
Abstrak: Indonesia as a tropical country with high ambient temperature and relatively humidity cause heat stress-related decreases in laying hen performance. Supplementation of antioxidants in the diet can reduce the negative effect of heat stress. This study was aimed to determine the effects of Vitamin E, and Selenium supplementation in the diets on the performances of Isa-Brown laying hens aged 46-51 weeks. Ninety six 46-weeks-old of laying hens were randomly assigned to 4 treatments, 4 replications of 6 birds each. The birds were fed either P1 = control diet or P2 = control diet supplemented with Selenium (0.8 ppm Se optimin), P3 = control diet supplemented with vitamin E (300 mg DL-α-tocopherol-acetate/kg diet), or P4 = control diet supplemented with combination of Vitamin E and Selenium (300 mg DL-α-tocopherol-acetate plus 0.8 mg Se optimin). Statistical analysis results showed that the treatments did not influence (P>0.05) the parameters observed. However, the result showed that combination of Vitamin E and Selenium supplementation tend to increase the egg weight and decrease the feed conversion.
Keyword: vitamin E, selenium, performance, laying hen, heat stress

Judul: Pengaruh Suplementasi Vitamin E dan Selenium dalam Ransum terhadap Kualitas Telur dan Profil Darah Ayam Petelur Umur 45- 51 Minggu
Abstrak: Vitamin E and selenium are primary antioxidants and essential microminerals, that has synergism interaction to prevent lipid peroxidation damage in the body cell. This study was aim to determine the effect of supplementation vitamin E, selenium, and its combination on egg quality, selenium content of egg, and blood profile. A Completely Randomized Design (CRD) with 4 treatments and 4 replication was used in this experiment. The variables observed were egg quality, selenium content of egg, and blood profile. This study used 96 of 45 weeks old of Isa Brown layer. The treatments were P1 = control diet, P2 = P1 + 0.8 mg kg-1 selenium, P3 = P1 + 300 mg kg-1 vitamin E, P4 = P1 + 300 mg kg-1 vitamin E + 0.8 mg kg-1 selenium. The results showed that selenium 0.8 mg kg-1 was affected decreased shell thickness. Supplementation of Selenium, vitamin E and its combination increased egg selenium content.
Keyword: vitamin E, selenium, egg quality, blood profile

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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