• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.233-238
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• 2006

In order to study the effect of feeding rare earth(RE) on growth of broiler chicks, feed conversion ratio, and probable harmfulness of feeding high levels of RE, two feeding trials with broiler chicks were conducted; one using a commercial broiler compound feed and the other using a self mixed feed excluding any growth stimulating feed additives. The the first trial used three hundred sixty of one day old Cobb broiler chicks for six levels of dietary supplementation of RE : 0, 100, 200, 400, 800 and 1,600 mg/kg. There were significant effect of RE stimulating broiler chick growth and improving feed conversion ratio, The dietary supplementation of RE at a level of 100 mg/kg was the best of all and increased body weight gain by 8.9% (p<0.05). Chicks fed RE at a level of 1,600 mg/kg grew as good as chicks fed feeds without RE and did not show my abnormalities. The second feeding trial was conducted in the same manner as the first trial using Ross broiler chicks and self-mixed experimental diets supplemented with RE at levels of 0, 50, 100 and 150 mg/kg. Differently from Results of the first trial, body weight gain and feed conversion ratio of were the best at the level of 50 mg/kg RE supplementation(p<0.05). In this trial all the birds fed RE showed significantly lower ratio of abdominal fat against live weight than those of the control group birds. Overall, it can be said that dietary supplementation of RE will improve broiler growth and feed conversion ratio and the proper dietary level would be $50\sim100mg/kg$. These results suggested that the proper level of RE for broiler chicks would be 50 to 100 mg/kg and its effectiveness is varied depending upon RE mixture. There appears abdominal fat of broiler chicks is decreased by feeding RE but further investigation is in need.

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.389-397
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• 2017

The purpose of this study was to investigate the characteristics of species by comparing the external shape traits and skull size of Tscherskia triton in Jeju Island from May 2014 to November 2016. Body weight, head-body length, ear length, and hind-foot length were not statistically significant (p>0.05), but tail length was statistically significant in females compared to males (p=0.003). To examine the secondary sexual dimorphism characteristics of the collected T. triton, B_HR, T_HR, E_HR, and H_HR were calculated based on the head-body length, and only T_HR was statistically significant (p=0.003). Because of comparing male and female averages, among the 21 traits, the greatest length of skull (GLS; p=0.020) and occipitonasal length (ONL; p=0.014) were statistically significant and length of incisive foramen (LIF) was statistically significant, when the significance level was 90%. However, the other 18 traits did not show statistically significant differences between males and females (p>0.05). Other than GLS, ONL, interorbital breadth (IB), and breadth of occipital foramen (BOF), there was female-biased SSD. The results of this study are the analysis of external morphology and skull characteristics of T. triton in Jeju Island and will be used as basic data to understand the morphological characteristics of T. triton. In addition, the data can be used as a basic information to compare characteristics of T. triton, which is known as a single species, inhabited in China and Russia. The data will play an important role in biogeography and ecology research of T. triton, based on geographical conditions, climate effects, and habitat environment.