Judul: Suplementasi Selenium Dan Vitamin E Terhadap Kandungan Mda, Gsh-Px Plasma Darah Dan Bobot Organ Limfoid Ayam Broiler Yang Diberi Cekaman Panas
Abstrak: High environmental temperatures may cause heat stress in poultry. High temperatures contributes to oxidative stress, a condition where oxidant activity (free radical) exceeds antioxidant activity. In this research, selenium and vitamin E were utilized as anti heat-stress agents for heat stress broilers. The research used 465 unsex broilers and they were divided into 2 conditions, comfort zone (25.22±0.05 oC) and high temperatures (29.80±0.76 oC). Variables measured were malondialdehyde (MDA), glutathione peroxidase (GSH-Px) in blood plasma and weight of lymphoid organ (bursa fabricius and tymus). The data collected were analyzed with a factorial completely randomized design of 3x3 (3 levels of vitamin E, 3 levels of selenium and 3 replication) and continued with Duncan test. The result showed that selenium and vitamin E supplementation was significantly decreased on MDA (p<0.05) and GSHPx (p<0.01) in blood plasma of heat stressed broilers, but it did not effect the weight of bursa fabricius and thymus of broilers. It could be concluded that the combination vitamin E (200 or 100 ppm) and selenium (0.3 ppm) is the most effective as anti heat-stress agent in broilers.
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Judul: Pengaruh Suplementasi Berbagai Antioksidan Terhadap Performa dan Status Fisiologis Ayam Broiler yang Diberi Cekaman Terhadap Lingkungan Temperatur Tinggi
Abstrak: High ambient temperature results in heat stress on broiler chickens. Antioxidant is the most efficient suplement, which alleviate the negative effects of heat stress. This study was conducted to determine the effects of antioxidants suplementation on performance and physiological status of broiler chickens exposed to high environmental temperature. Ten days-old 48 broilers were randomly assigned to a 2x3 factorial design to 3 environmental treatments, 2 experimental diets of 8 replication of one birds each. The chickens were fed a commercial diet with or without mixed antioxidants. The environmental treatments were as follows: constant temperature at 25 ˚C, cyclic temperature at 25-35-25 ˚C, and constant temperature at 32 ˚C. Chickens in high environmental temperature had lower (P<0.01) feed intake, body weight, and body weight gain than in normal temperature. Antioxidants suplementation had no effect on performances and physiological. Antioxidants suplementation increased yellowness (P<0.05) of breast muscle. Antioxidants and environmental treatments did not influence malondialdehyde (MDA) level. These results suggested that antioxidants did not alleviate the negative effect of heat stress on broiler chickens.
Keyword: heat stress, broiler, antioxidants

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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