• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.4
• /
• pp.232-238
• /
• 2005

This paper describes reproduction, population structure, growth and size at sexual maturity of a deep-water mud shrimp (Solenocera melantho) in the adjacent waters of Geomun Island, Korea. The shrimp was caught by a beam trawl from November 1998 to December 1999. Spawning period was estimated by gonadosomatic index to be from August to early November with a peak in October to early November. Female shrimps were $12\%$ matured at 16 mm in carapace length, $33\%$ matured at 18 mm and $75\%$ matured at 22 mm. The size at $50\%$ maturity for female was estimated to be 20.65 mm in carapace length. Breeding season was estimated to be from August to early November with a peak in October to early November. The size at $50\%$ inseminated was 19.81 mm CL. The fecundity was 87,500-405,200 and related exponentially to carapace length and total weight. This species survived between 25 and 26 months. The maximum carapace length of females and males were 48 mm and 34 mm respectively. Sex ratio was $51.3\%$, and the females were preponderant. Growth was estimated by modified von Bertalanffy growth function incorporating seasonal variation in growth in both years females (K=1.019/yr and $L_{\infty}$=51.731 mm CL) grew faster, reaching a larger size at a given age than males (K=1.848/yr, and $L_{\infty}$=27.499 mm CL). This is indicated by differences in growth performance indices $(\varphi')$ between females (3.291) and males (3.145).

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.3
• /
• pp.359-364
• /
• 2007

The objective of this study was to evaluate monthly variation in semen characteristics in Black Bedouin and Black Bedouin${\times}$Damascus crossbred bucks. Twenty one Black Bedouin Goat bucks (BG) and 20 $F_1$ Black Bedouin${\times}$Damascus crossbred goat bucks (CB) were used in the study. Animals were 2 to 5 years old at the beginning of the study. Body weight (BW), body condition score (BCS), scrotal circumference (SC) and semen samples were evaluated monthly for all bucks. Body weight, BCS and SC differed according to month of collection (p<0.0001). Body weight and BCS were greater in the spring and summer months while SC reached their highest values during the autumn months. No differences were detected between breeds with respect to semen characteristics with the exception of ejaculate volume (p<0.05) and ejaculate appearance (p=0.053) which were greater in CB than in BG bucks. With the exception of ejaculate appearance, all semen characteristics were influenced by month of collection (p<0.05). Semen concentration and motility were better during the late summer and autumn months than during the spring. The percentage of abnormal spermatozoa declined from its greatest values in the spring to its lowest values in the autumn. Results of the present study show no effects of goat breed on most of the studied parameters. In general, most semen quality parameters were better in both breeds during the autumn than the spring months. Minimal variation in semen quality was observed between the summer and autumn months indicating the ability to use bucks for semen collection and for natural breeding during both of these seasons.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.7
• /
• pp.1060-1068
• /
• 2009

The buffalo (Bubalus bubalis) is an important contributor to milk, meat, power, fuel and leather production in many developing countries. Buffaloes can be categorized into Asian and Mediterranean buffaloes. Asian buffalo includes two subspecies known as Riverine and Swamp types. Riverine (water buffalo) and Swamp buffaloes possess different genetics (50 vs. 48 chromosomes, respectively), morphology (body frame, body weight, horn shape and skin color) and behavior (wallowing in mud or water) and thus, are reared and used for different purposes. Low per head milk yield, poor reproductive performance (seasonal breeding behavior, anestrous, and longer calving interval) and low growth rate in buffaloes have been attributed to insufficient supply of nutrients. In many parts of Asia, where the buffalo is an integral part of the food chain and rural economy, irregular and inadequate availability of quality feedstuffs and their utilization are hampering the performance of this unique animal. Balanced nutrition and better management can enhance buffalo productivity. Many efforts have been made in the last few decades to improve nutrient supply and utilization in buffaloes. Recent research on locally available feed resources such as crop residues, and industrial by-products, dietary addition of micronutrients, use of performance modifiers and use of ruminally protected fat and protein sources have shown significant potential to improve growth, milk yield and reproductive performance of buffaloes. However, a number of issues, including establishment of nutrient requirements for dairy and beef, development of buffalo calf feeding systems, nutritional management of metabolic and reproductive anomalies, and understanding and exploitation of the buffalo gut ecosystem, need to be addressed. Extensive coordinated research and extension efforts are required for improved buffalo nutrition in developing countries.

• Korean Journal of Environmental Biology
• /
• v.32 no.3
• /
• pp.263-269
• /
• 2014

In this study, I investigated the species composition in the Mulberry tree cultivation area from April 2013 to March 2014 at Busan. Five genera and nine species found are as follows: Aporrectodea caliginosa (Savigny, 1826), Bimastos parvus (Eisen, 1874), Eisenia fetida (Savigny, 1826), Drawida japonica (Michaelsen, 1892), Amynthas heteropodus (Goto&Hatai, 1898), Amynthas agrestis (Goto & Hatai, 1899), Amynthas corticis (Kinberg, 1867), Amynthas hilgendorfi (Michaelsen, 1895), and Amynthas sp. A total of 317 individuals of Aporrectodea caliginosa (Savigny, 1826) was collected. Ap. caligionosa and A. heteropodus were found to be the most dominant species during the study period. Interestingly, the maximum population density of Ap. caligionosa was recorded to be in the month of October. Further details analysis indicated that, its population increased rapidly during the breeding season between summer and autumn and thereafter gradually decreased through winter toward the following February. Three growth stages of Ap. caligionosa occurred almost simultaneously with abundance composition of 76% in aclitellum, 12.6% in semiclitellum, and 11.4% in clitellum. Based on my study results, I suggest that this data could be useful for the scientific community to analyze the distribution of southern earthworm species in mulberry tree cultivation area.

• Development and Reproduction
• /
• v.6 no.1
• /
• pp.45-54
• /
• 2002

Reproductive activity of golden hamsters(Mesocricetus auratus) is regulated by the photoperiod. They are sexually active in summer and inactive in winter. Melatonin, a pineal hormone, has been known to mediate sexual activities in seasonal breeding animals. Melatonin receptor was recently identified in several animal species including hmm. But little has been known about it in relation to the reproductive activities of golden hamsters. By using reverse transcription polymerase chain reaction(RT-PCR) methods, a portion of the melatonin receptor gene(309 nucleotides) was identified in golden hamsters. The nucleotide sequence of the melatonin receptor and the amino acid sequence deduced were compared to those reported in other animals. Melatonin receptors were obviously detected in hypothalamus, pituitary containing pars tuberalis, blood, and spleen. Although the testicular weights and the levels of reproductive hormones were dramatically affected by photoperiods, the expression of melatonin receptor was not markedly changed by them. These results suggest that the action of melatonin in regulating reproduction might be mainly due to the affinity of melatonin receptor rather than the density fi melatonin receptor.

• Applied Microscopy
• /
• v.28 no.4
• /
• pp.447-463
• /
• 1998

This study was carried out to investigate the histomorphological changes and the electrophoretic patterns of egg components, obtained from 100 of 2-year-old female catfishes (Silurus asotus). Female Korean catfishes collected in the vicinity of Chollabukdo have synchronous ovaries which discontinously ovulate eggs during the breeding season (from late May until early July). The fishes were killed by severing the spinal cord just posterior to the head after immobilization with tricaine methanesulfonate (MS 222). Especially, the light microscopic and ultrastructural changes of ooplasm and follicular membranes of oocytes, were examined by means of light and transmission electron microscopy. The size of the nucleoli and number of the yolk granules increased as the oocyte groved. Yolk granules were deposited in the oocyte as fluid Due to tile presence of large early and late maturing oocytes, their ovaries were enlarged, transparent, granular and greenish in color. As the percentages of fish in late maturing oocyte (LMO) and ripe oocyte (RO) stage increased from March to April, mean gonadosomatic index (GSI) values (19.95%) increased. Zona radiata changed from squamous into cuboid in shape in the early maturing oocyte (EMO) stage. Processes, microvilli, from the zona radiata and from the oocyte grow, and make contact with each other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radials becomes more compact and devoid of pore canals during oocyte maturation. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in both gonadosomatic index and macroscopic appearance. The main cytological changes such as increase in size of cell, nucleus, nucleolus, and increase in number of nucleoli and mitochondria demonstrated with electron microscopy in the previtellogenic oocytes of Korean catfish, provided evidences for important synthetic processes in an early preparatory phase of oocyte development. The electrophoretic pattern of major band in mature stage was much thicker (24 k, 66 k, 90-110k dalton) than that in previtellogenic phase.

• Journal of Animal Science and Technology
• /
• v.63 no.4
• /
• pp.759-765
• /
• 2021

Recently, summer temperatures have frequently been abnormal in Korea owing to global warming. In summer, a decrease in feed intake rate and biological activity were observed in Hanwoo (Korean Native Cattle), leading to lower production rates in the industry. However, the precise scale of damage was not reported as with other animals of economic value. This study was conducted to investigate the effects of birth season on birth weight in Hanwoo. Data were collected from 100 local breeding farms from 2016 to 2019. A total of 41,081 Hanwoo calves were classified and analyzed by sex, year, month, and season (March-May, spring; June-August, summer; September-November, fall; and December-February, winter) of birth. The birth weight of Hanwoo calves differed according to birth month. The average birth weight of male calves was 30.47 kg and that of female calves was 28.16 kg. Hanwoo birth weight was the highest in March-born calves and the lowest in July-born calves. The birth weights of calves born in February, March, April, November, and December were significantly larger than those of calves born in July. In addition, the birth weight of Hanwoo calves from the summer was significantly lower than that of calves born in other seasons. Furthermore, Hanwoo steer slaughter age showed a negative correlation, whereas carcass weight had a positive correlation with birth weight. In the beef cattle industry, birth weight is a very important economic characteristic that is related to growth rate. These data will contribute toward planning the reproduction of Hanwoo and analysis of changes in characteristics of economic value owing to high temperatures.

• Journal of Plant Biotechnology
• /
• v.45 no.4
• /
• pp.306-314
• /
• 2018

Korean ginseng (Panax ginseng) has long been cultivated as an important economic medicinal plant. Owing to the seasonal and long-term agricultural cultivation methods of Korean ginseng, they are always vulnerable to various environmental stress conditions. ABSCISIC ACID (ABA) is an essential plant hormone associated with seed development and diverse abiotic stress responses including drought, cold and salinity stress. By modulating ABA responses, plants can regulate their immune responses and growth patterns to increase their ability to tolerate stress. With recent advances in genome sequencing technology, we first reported the functional features of genes related to canonical ABA signaling pathway in P. ginseng genome. Based on the protein sequences and functional genomic analysis of Arabidopsis thaliana, the ABA related genes were successfully identified. Our functional genomic characterizations clearly showed that the ABA signaling related genes consisting the ABA receptor proteins (PgPYLs), kinase family (PgSnRKs) and transcription factors (PgABFs, PgABI3s and PgABI5s) were evolutionary conserved in the P. ginseng genome. We confirmed that overexpressing ABA related genes of P. ginseng completely restored the ABA responses and stress tolerance in ABA defective Arabidopsis mutants. Finally, tissue and age specific spatio-temporal expression patterns of the identified ABA-related genes in P. ginseng tissues were also classified using various available RNA sequencing data. This study provides ABA signal transduction related genes and their functional genomic information related to the growth and development of Korean ginseng. Additionally, the results of this study could be useful in the breeding or artificial selection of ginseng which is resistant to various stresses.

• Development and Reproduction
• /
• v.24 no.4
• /
• pp.263-275
• /
• 2020

The proper administration of melatonin has well been documented to induce testicular regression in seasonal breeding animals. The subcutaneous injections of melatonin in the afternoon, not in the morning, consistently occurred testicular involution in the male Syrian (golden) hamsters whose reproductive activity is regulated by the photoperiod. But the effects of daily melatonin via gavage have not been estimated. Golden hamsters housed in long photoperiod (LP) were divided into 5 groups: the control animals housed in LP or in short photoperiod (SP) and animals treated daily with low (15 ㎍), middle (150 ㎍), and high dosages (1,500 ㎍) of pure melatonin by using gavage in the evening for 8 weeks. As results, LP control animals had large testes and SP controls displayed small and entirely regressed testes. The animals treated with various dosages of melatonin showed collectively degenerating effects on the weights of testes, epididymides, and seminal vesicles in the middle and high dosage groups, with the individual differences as well. The high dosages induced testicular regression in more proportion than the middle dosages did. The low dosage had large testes like the LP control animals. The small and inactive testes shown in some animals of both middle and high groups presented the complete regression as those of the animals maintained in SP. These results strongly suggest that the administrations of melatonin lead to testicular involution in the male golden hamsters when it is administered through gavage.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.45 no.1
• /
• pp.22-28
• /
• 2022

Silkworms are very sensitive to changes in temperature and humidity, and unless it is a suitable temperature and humidity to grow, the productivity and quality of silkworms are greatly reduced. Therefore, it is very important to manage temperature and humidity for silkworm feeding facilities. In particular, it is essential to install heating facilities in Asian countries with distinct seasonal changes. During the feeding period, many farms manage the temperature and humidity of feeding facilities by installing and using electric heaters inside the facilities. However, it is very difficult to manage the room temperature stably by the heaters. In addition, unlike the temperature inside the facility, silkworms could undergo severe temperature changes as the inside of the rearing tray could not be warm enough. In this study, in order to improve the previous heating method, the new rearing method that directly heats the bottom of the rearing tray was developed. Compared to the previous room-heating system, the novel heater-installed tray (HIT) system significantly reduced the change in temperature during the experimental period. In addition, the number of days of silkworm growth up to harvest was shortened, which was effective in growth performance, and it was also found that silkworms grew more uniformly in HIT system than in previous system. Moreover, as the heater tubes were installed directly under the rearing tray, it quickly dried mulberry leaves and silkworm feces after feeding, and as a result, the environment in the tray was greatly improved with decrease the labor of breeder. In conclusion, these results suggest that the heater-installed rearing tray method greatly improves silkworm quality, increases weight of silkworms, and final profits compared to the previous room heating system with electric heaters.