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: Evaluation of Vitamin D3 Supplementation in Feed on the Physical Quality of Eggs from Lohmann Layer Hens Aged 91-94 Weeks
Abstrak: Penelitian ini bertujuan untuk mengevaluasi efek suplementasi Vitamin D3-500 dalam pakan terhadap kualitas fisik telur dalam upaya mempertahankan kualitas telur ayam petelur Lohmann di umur tua. Penelitian ini menggunakan 108 ekor ayam petelur dengan strain Lohmann Brown umur 91 minggu hingga umur 94 minggu dan rataan bobot badan 1801-1840 g ekor-1. Penelitian ini menggunakan Rancangan Acak Lengkap yang terdiri atas 3 perlakuan dan 4 ulangan serta tiap ulangan menggunakan 9 ekor. P0=Pakan kontrol (tanpa suplementasi Vitamin D3), P1=Pakan kontrol + suplementasi Vitamin D3 1,0 g kg-1, P2=Pakan kontrol + suplementasi Vitamin D3 1,5 g kg-1. Peubah yang diukur meliputi bobot telur, tebal kerabang, warna kuning telur, indeks telur, haugh unit, persentase bobot telur, konsumsi kalsium, dan konsumsi fosfor. Data dianalisis menggunakan ANOVA. Hasil penelitian menunjukkan suplementasi Vitamin D3-500 tidak berpengaruh nyata terhadap bobot telur, tebal kerabang, warna kuning telur, indeks telur, haugh unit, persentase bobot telur, namun kualitas fisik telur masih termasuk dalam standar yang baik. Kesimpulan peneletian ini adalah suplementasi Vitamin D3 sampai dosis 1,5 g kg-1 pakan tidak berpengaruh terhadap kualitas fisik telur, karena kandungan Ca da P dalam ransum serta konsumsinya sudah mencukupi kebutuhan ayam Lohmann umur 91-94 minggu., This study aimed to evaluate the effects of Vitamin D3-500 supplementation in feed on the physical quality of eggs, focusing on maintaining the quality of older Lohmann Brown laying hens. The study involved 108 hens aged 91 to 94 weeks with an average body weight of 1801-1840 g each. It utilized a Completely Randomized Design with 3 treatments and 4 replications, each consisting of 9 hens. The treatments were: P0 = Control diet (no Vitamin D3 supplementation), P1 = Control diet + Vitamin D3 supplementation at 1.0 g kg-1, P2 = Control diet + Vitamin D3 supplementation at 1.5 g kg-1. Variables measured included egg weight, shell thickness, yolk color, egg index, haugh unit, egg weight percentage, calcium consumption, and phosphorus consumption. Data were analyzed using ANOVA. Results indicated that Vitamin D3-500 supplementation did not significantly affect egg weight, shell thickness, yolk color, egg index, Haugh unit, or egg weight percentage. Despite this, the physical quality of the eggs remained within acceptable standards. The conclusion of this study is that supplementing Vitamin D3 up to 1.5 g kg-1 in the diet did not influence egg quality, as the dietary calcium and phosphorus content met the requirements for Lohmann hens aged 91-94 weeks.
Keyword: egg physical quality, Laying hens, Vitamin D3, aged laying hen

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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