• Reproductive and Developmental Biology
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• v.34 no.2
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• pp.89-94
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• 2010

Melatonin is induced by light information through the retina and leads to growth factor activation. Thus, we investigated the effects of melatonin by controlling the photoperiod of growing young rats. Male Sprague-Dawley rats (n=6; 4 weeks old) were divided into two experimental groups: the L/D group (normal photoperiod; light/dark: 12/12 h; lights on at 9:00 a.m.) and the L/L group (light/light: 24 h). Rat body weight and food consumption were measured daily for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of ketamine (50 mg/kg) and xylazine (10 mg/kg) and sacrificed. Tissue was then collected for RNA isolation (from brain, heart, liver, kidney, adrenal gland, testis, tibia, hind limb muscles). Also, serum was isolated from blood using a centrifugal separation. The L/L group had significantly lower body weight than the L/D group from 4 to 6 weeks (p<0.05). The L/D group had increased tissue mass, compared with the L/L group, but the difference was not statistically significant. The L/D group had a significantly higher melatonin concentration than the L/L group between the hours of midnight and 2:00 a.m (p<0.01). These results indicate that photoperiod length may affect the secretion of melatonin from the pineal gland. Also, the reduction of nocturnal melatonin secretion may retard the development of growing young rats. In future studies, we plan to compare exogenous melatonin administration with endogenous melatonin concentration induced by photoperiod control. Moreover, we will confirm whether the effects seen in pathological animal models can be reversed by controlling the photoperiod.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.159-167
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• 2020

This study investigated the effect of different light sources in the poultry house on performance, meat quality, and blood composition of finishing broilers. Two hundred and forty male broilers (1-day-old, 42.2±0.1 g) were divided into three groups and subjected to different light source treatments (incandescent, LED, and fluorescent lamps) from 3 weeks of age (four replications/treatment, 20 birds/replication). After breeding for 6 weeks, the carcass yield and meat quality of broilers with similar body weight (BW; 3.4±0.07 kg) were investigated, and blood components were analyzed. Corn-soybean meal-based feed was provided as starter (CP 22.5%, ME 3,020 kcal/kg), early (CP 18.5%, ME 3,050 kcal/kg), and finishing (CP 18%, ME 3,100 kcal/kg). Performance, carcass yield, meat quality, and blood components were evaluated. BW, BW gain, feed intake, and feed conversion ratio did not show any significant differences among treatments. There was no significant difference on live weight and carcass yield among treatments. There was no significant difference on meat color, shear force, and water holding capacity; however, cooking loss at 17.2% was the highest in the LED treatment (P<0.05). There was no significant difference on blood components except for glucose (blood biochemistry component) among treatments. Glucose was 234.5 mg/dL, 256.9 mg/dL, and 250.1 mg/dL in the three treatments, respectively, with a significant difference between incandescent and LED treatments (P<0.05). These results are used useful as basic data for investigating the effect of lighting in broilers production.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.13-22
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• 2021

The present experiment was conducted to evaluate the effect of stocking density on the growth performance, immune status, and meat quality of broilers. In total, 385 one-day-old Ross 308 broilers were randomly assigned to one of four distinct stocking densities: 26 birds/㎡, 22 birds/㎡, 19 birds/㎡, and 16 birds/㎡. They were fed the diet ad libitum for 5 weeks. Immunoglobulin (Ig) and corticosterone levels were evaluated, and growth performance, blood parameters, and breast meat quality were determined. It was observed that the weight gain and feed intake of growers (21~35 d) and broilers (0~35 d) were significantly reduced as the stocking density increased (P<0.05). However, the feed intake of starters (0~21 d) significantly increased as the stocking density increased (P<0.05). There were no significant differences in the biochemical profiles among the four different stock densities. Furthermore, no significant differences were observed in the stress parameters: (heterophils / lymphocytes ratio and corticosterone), IgA, and IgM; however, IgG significantly increased with stocking density (P<0.05). The pH, water holding capacity, and cooking loss of the muscle were all unaffected by the stocking density, but the shear force (tenderness) increased slightly as the density increased. The findings of this study suggest that a lower stocking density (16 birds/㎡) significantly improved the shear force of breast meat and IgG in broilers.

• Animal Systematics, Evolution and Diversity
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• v.7 no.1
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• pp.151-176
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• 1991

The arthropods are the most diverse and successful animal group making up more than three quarters of the total animal species. They also live in a great diversity of habitats on the earth. Because of these unavoidable circumstances, the human life has always been affected by them. Therefore, in many countries from the past, governments have supported the studies of the arthropods on the basis of the national policy. However, the present situation of ours is far behind the other advanced contries, Now we urgently need governmental support fro the development of both the basic and the applied fields of arthropod studies in the well organized manner. Facing with this necessity, the present article reviewed the studies of Korean arthopods based on insect and crustacean representing most of the arthopods. Several subjects were reviewed in the section of the past and present studies on Korean arthropods. These are the studies on Korean arthropods in the past and present, their application to the national strategy, and the present condition of curating specimens, etc. From these reviews, several important points were suggested in the section of future plan. These are such subjects as the establishment of national institution for the curation of specimens , computerizing the data, diversification of research techniques, valid strategy concerning the control of harmful contribution to the nature conversation and environmental management , use as a research animal, the enhancement of public welfare, training of specialists, and policies for the national programs.

• Korean Journal of Poultry Science
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• v.48 no.3
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• pp.143-150
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• 2021

In this study, we investigated the effects of light intensity on broiler chick growth performance, blood parameters, and stress levels. A total of 240 one-day-old male Ross 308 broilers (47.97±0.166 g) were subjected to three different intensities of light (20, 30, and 50 lx), with each treatment being conducted with four replicates. On the seventh day, the growth performance (body weight, feed conversion ratio, and breast muscle and liver weights) and blood parameters were determined; the levels of serum corticosterone, interleukin-6 (IL-6), and tumor necrosis factor-α were also evaluated. The body weight, weight gain, liver weight, and breast muscle weight of chicks exposed to a light intensity of 50 lx were significantly increased compared with those of chicks subjected to 20 lx (P<0.05). No significant differences were observed in the leukocyte, erythrocyte, and platelet counts and the biochemical profile exceptions being the levels of glucose and inorganic phosphorus in the blood of the chicks in the three light intensity groups. However, serum corticosterone and IL-6 levels were the highest in chicks exposed to a light intensity of 20 lx (P<0.05). In conclusion, the findings of this study indicate that broiler chicks exposed to higher light intensity (50 lx) show significant improvements in terms of weight gain and corticosterone and IL-6 levels. Thus, high light intensities enhanced the growth performance, stress levels, and immune status of broiler chicks.

• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.139-144
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• 2022

This study was conducted to investigate the effect of three different photoperiods on growth performance, blood properties, and stress indicators in broiler chicks between 1-7 days after hatching. Two hundred and fifty-two 1-day-old male broiler chicks (57.0±0.12 g) were divided into three treatments, with 4 replicates per treatment and 22 birds per replicate subjected to three different photoperiods of 24L, 22L/2D and 18L/6D. A light-emitting diode bulb served as the light source, with an illuminance of 30 lx. As an experimental diet, a commercial feed based on a corn-soybean meal, with 22% CP and 3,150 kcal/kg ME diet, and water were fed ad libitum. Body weight gain, feed conversion ratio, and liver weight ratio showed a statistically significant difference between the 18L/6D and 24L treatments (P<0.05), but with no significant difference between the 22L/2D treatment and either the 24L or 18L/6D treatment. The breast meat ratio was 5.59% in the 18L/6D treatment group, which was lower than that of other treatment groups (P<0.05). The triglyceride levels were highest (P<0.05) in the 18L/6D treatment among treatments, but alanine aminotransferase levels were significantly higher (P<0.05) in the 22L/2D treatment than in the 24L treatment. Levels of cytokines, i.e., Interleukin-6 and Tumor Necrosis Factor-α did not show a significant difference among the treatments, but corticosterone content was significantly higher (P<0.05) in the 24L treatment than in the 18L/6D treatment. In conclusion, 22 hours of lighting is appropriate between 1~7 days after hatching, considering growth performance and the overall health of broiler chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.7
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• pp.974-980
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• 2014

In semi-arid areas of Southern Africa, dehydration can compromise the performance and welfare of local chickens, particularly during the growing period when confinement is curtailed and birds are left to scavenge for feed and water. The effect of water restriction on the growth performance was compared in Naked Neck (NNK) and Ovambo (OVB) chickens that are predominant in Southern Africa. A total of 54 eight-wk-old pullets each of NNK and OVB chickens with an initial average weight of $641{\pm}10g/bird$ were randomly assigned to three water intake treatments, each having six birds for 8 wk. The water restriction treatments were ad libitum, 70% of ad libitum and 40% of ad libitum intake. Nine experimental pens with a floor space of $3.3m^2$ per strain were used. The pens were housed in an open-sided house with cement floor deep littered with a 20 cm layer of untreated wood shavings. Feed was provided ad libitum. Average daily water intake (ADWI), BW at 16 weeks of age (FBW), ADG, ADFI, feed conversion ratio (FCR) and water to feed ratios (WFR) were determined. Ovambo chickens had superior (p<0.05) FBW, ADG and ADWI than NNK chickens. Body weight of birds at 16 weeks of age, ADG, ADFI, ADWI, and WFR declined progressively (p<0.05) with increasing severity of water restriction while FCR values increased (p<0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40% of ad libitum water intake level than Ovambo chickens. The dressing percentage per bird was higher in water restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. In conclusion, NNK chickens performed better than OVB chickens under conditions of water restriction and would be ideal to raise for meat and egg production in locations where water shortages are a major challenge.

• Journal of the Korean Home Economics Association
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• v.33 no.6
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• pp.213-224
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• 1995

This study was designed to observe the nutritional knowledge, food behavior, nutritional attitudes and food preference of elderly living in home. Two hundred and thirty elderly were examined on questionnaire. The results of this study are summarized as follows. 1. The average score of their nutritional knowledge was 6.08 (the highest mark was 10.00). The nutrition knowledge score of the elderly live with spouse was higher than those live alone and goes up according to the education degree of elderly and pocket money. The correct answer ratio about a question of geriatric diseases was somewhat higher than another question. 2. The average score of their food behavior was 21.90(the highest mark was 33.00) and the score of the female was higher than that of the male and the college-educated elderly have the highest score. Generally their food behavior was improved by the increasing intake of animal protein and milk. 3. The average score of their nutritional attitude was 11.25 (the highest mark was 15.00) and those of 70~74 age old have the lowest score. And they answered that they are willing to change their food behavior for their health. In this study we expect that the authorities would operate the nutritional education for the prevention of degenerative diseases and the development of the food behavior at a public health center or another groups(no-in-jung) as a part of service for the welfare of elderly. 4. They prefered vegetable foods to animal foods and baking, broiling, and raw foods to the fried foods, and they liked the sweet foods, the fruits, milk and lactic acid beverage as snack or dessert.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.166-172
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• 2019

Heart rate is a relatively simple and non-invasive method that is used as an important physiological indicator in many studies and has a close relationship with heart structure and function, cardiovascular disease and sudden cardiac death. In general, appropriately low heart rate during resting means effective heart function and cardiovascular fitness; heart rate at recovery is an important indicator of health and disease condition. We found a beagle dog (Dog_1) with a high heart rate in the previous preliminary experiment. Therefore, purpose of this study was to compare the heart rate response of the Dog_1 with the control group during 12 weeks of interval exercise, to evaluate the structural and functional abnormalities of the heart and to verify the applicability of exercise program. Heart rate was checked during 12 weeks of interval exercise, and after the exercise was over, imaging examination and hematological and serum biochemistry were performed. As a result, Dog_1 (165.6 ± 1.5) showed significantly higher heart rate in low intensity session of interval exercise than control group (133.3 ± 0.5, p < 0.01). In addition, Dog_1 (181.2 ± 1.4) showed significantly higher heart rate than control group (155.1 ± 0.9) in high intensity session (p < 0.01). The heart rate (30 sec, 60 sec) during recovery state was higher in Dog_1 (30 sec: 156.8 ± 4.0, 60 sec: 166.8 ± 5.8) than in the control group (30 sec: 111.2 ± 2.5, 60 sec: 104.0 ± 5.1, p < 0.01). The results of the imaging examination of Dog_1 with high heart rate confirmed that the heart had no functional and structural abnormalities. All beagles with the interval exercise program did not show maladjustment, and in the hematological and serum biochemistry results, all the parameter were within the reference range. If the interval exercise program of this study is used in the future, it is expected to be used as an important basic data to achieve the purpose of health, welfare, and physical fitness improvement of dogs.

• Korean Journal of Veterinary Research
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• v.57 no.3
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• pp.155-158
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• 2017

Surgical castration performed to reduce male-associated problems results in pain and microbial infections in male animals. Therefore, immunocontraception, which is mediated by the animal's own antibodies against reproductive hormones, has been recommended as an alternative to surgical castration when considering the animal's welfare. In this study, a new immunocontraceptive vaccine composed of six tandem copies of gonadotropin-releasing hormone (GnRH) fused to rat granulocyte-macrophage colony-stimulating factor (GM-CSF) was developed, and its efficacy was evaluated in male rats. Three different doses (10, 50, and $100{\mu}g$) of recombinant GM-CSF-GnRH protein were injected three times at intervals of two weeks into male rats. The rats vaccinated with three doses of GM-CSF-GnRH produced a significantly higher level of antibodies against GnRH than that in the negative control rats. Severe atrophy of gonads was observed in rats vaccinated with three doses of GM-CSF-GnRH but not in the negative control rats. The results reveal that the new GnRH vaccine conjugated with rat GM-CSF induces efficient immunocontraception in male rats. This formulation of the immunocontraceptive vaccine would be applicable to both domestic and pet male animals.