The diet composition of Takifugu niphobles was studied with 587 specimens collected in the eelgrass bed of Jangpyeong-ri, Tongyeong, Korea, using a seine net, monthly from May 2016 to April 2017. The standard length (SL) of the specimens ranged from 0.7 to 9.0 cm. The stomach contents analysis indicated that T. niphobles consumed mainly amphipods (%IRI: 91.0 %). In addition, T. niphobles fed on small quantities of copepods, polychaetes, insects, bivalves and crabs. T. niphobles consumed mainly amphipods over all size class. Smaller individuals (less than 4 cm SL) fed mainly on amphipods and copepods. The proportion of copepods decreased, as body size increased, whereas the consumption of polychaetes increased gradually. The seasonal variation in the diet composition of T. niphobles was significant. Amphipods were most common prey in all seasons. Copepods decreased from summer to spring gradually whereas the consumption of polychaetes increased in autumn.

복섬, Takifugu niphobles 부화 자어를 대상으로 기아에 따른 성장, 생존 및 간세포 핵 크기에 미치는 영향을 조사하였다. 자어의 전장은 부화 후 3일 까지 증가하였으나 부화 후 3일에서 부 화 후 6일까지 절식구는 공급구에 비해 유의한 낮은 성장을 보였다. 공급구 복섬의 체중은 실 험 기간 중 지속적인 증가를 보였다. 절식구의 체중은 부화 후 3일 까지 증가하였으나, 부화 후 3일 이후는 서서히 감소하였다. 절식구의 생존율은 공급구의 생존율에 비해 유의하게 낮았 으며(p < 0.05) 부화 후 6일째 절식구 자어는 폐사하였다. 절식구의 간세포 핵 크기는 부화 후 3일 까지는 공급구의 간세포 핵 크기와 유의한 차이가 없었으나, 부화 후 4일에서 부화 후 6일 까지는 절식구은 공급구에 비해 간세포 핵 크기 감소를 보이며 조직상 차이를 보였다. 본 연구 결과 도출된 자료들은 복섬의 영양상태 지표로 사용될 수 있을 것으로 사료된다.

연안산 저활용 소형복어인 복섬(Takifugu niphobles)을 원료로 하여 수프용 정미강화소재로 이용할 수 있는 풍미계 조미엑스분을 추출하였고, 추출방법에 따른 이들 복섬 엑스분의 품질 및 정미발현성분에 대하여 살펴보았다. 복섬의 조단백질 함량은 17.4%으로 Glu, Asp, Lys, Leu, Pro, Ala, Val 및 Lys 등 주요 아미노산을 고루 함유하고 있었다. 열수추출법 및 2단 효소분해법으로 엑스분을 추출하고 관능적 특성을 비교한 결과, 98℃에서 3시간 추출한 열수추출물에서는 감칠맛과 맛의 강도가 약한 반면, 2단 효소분해물은 감칠맛과 맛의 조화가 월등히 우수하였고, 수율은 열수추출에 비해 약 1.7배 증가하였다. 열수추출 및 2단 효소분해물의 유리아미노산 총량은 각각 433.1 및 4,502.2 mg/100 g으로 함량 차이가 컸으며, Pro, Leu, Lys, Hypro, Tau, Arg, Phe, Ala, Glu 및 Val 등이 복섬 2단 효소분해물의 주요 유리아미노산이었다. 반면, IMP 함량은 각각 336.2 및 372.2 mg/100 g으로 다량 함유되어 있었으나 양자 간에 큰 차이가 없었고, 그외 total creatinine 등 기타 염기성분도 추출방법에 따른 함량 차이는 거의 없었다. 주요 정미발현성분 중의 하나인 무기이온은 Na, K, Cl 및 PO4 등이 주성분으로, 열수추출물에 비해 2단 효소분해물의 함량이 훨씬 많았다.

In order to examine the effects of four different light spectra (white, red, green, and blue) on the oocyte maturation, the change of reproductive parameters, via brain-pituitary-gonad (BPG) axis in grass puffer, were investigated. After exposure four different light spectra for 7 weeks, the abundance of gonadotropin-releasing hormone (GnRH) mRNA which is a type of seabream (sbGnRH) and two different subunit of gonadotropin hormones mRNAs, follicle-stimulating hormone (fshβ) mRNA and luteinizing hormone (lhβ) mRNA, were analyzed in the brain and pituitary. Histological analysis showed that the mature oocyte ratio in the green spectrum was higher than other light spectra-exposed groups. Gonadosomatic index (GSI) and oocyte developmental stage were also investigated in the gonad based on histological observations. GSI value with the presence of yolk stage oocytes was significantly increased in the green spectrum-exposed group when compared to that of the other light-exposed groups (white, red, and blue) (p˂0.05). The abundances of sbGnRH mRNA and fshβ mRNA in the green spectrum-exposed group were also significant higher than those of the other light spectra-exposed groups (p˂0.05). These results indicate that the maturation of oocyte in grass puffer can be accelerated by exposure to the spectrum of green. To better understand the molecular mechanism for the maturation of oocyte in grass puffer, further study examining the relationship between oocyte development and its related genes is required.

The objective of this study was to determine the mitotic intervals (τ0) of two consecutive cell divisions and synchronous embryonic cleavage in grass puffer, Takifugu niphobles at different water temperatures (18, 20, 22, and 24℃). The color of the fertilized egg was light yellowish. The egg type was demersal and unadhesive. Egg weight was 0.09±0.002 mg. The sizes of unfertilized eggs were smaller than fertilized eggs in major axis and minor axis at 20℃ (p<0.05). The size of the fertilized egg of 18℃ water temperature group at the blastodisc stage was the smallest (p<0.05), but no significant differences were observed in the other water temperatures group except 18℃ water temperature group (p>0.05). The first cleavage stages at 18, 20, 22, and 24℃ were at 75, 90, 105, and 120 mins, respectively. As water temperature was increased, embryonic development and formation time of the first cleavage furrow were accelerated. There were negative correlation between τ0 and water temperature for grass puffer (Y=–1.225X+70.05, R2=0.988, n=10, where Y was τ0 and X was temperature). This study confirmed that successful hatching of grass puffer was related to water temperature. Chromosome manipulation will be helpful for this species using cleavage frequency and τ0.

In order to examine the effects of four different light spectra (i.e., white, red, green, blue) on the oocyte maturation in grass puffer, the change of reproductive parameters via brain-pituitary-gonad (BPG) axis were investigated in this study. After exposure to four different light spectra for 7 weeks, the abundance of gonadotropin-releasing hormone (GnRH) mRNA which is a type of seabream (sbGnRH) and two different of subunit of gonadotropin hormones mRNAs, follicle-stimulating hormone (fshβ) mRNA and luteinizing hormone (lhβ) mRNA, were analyzed in the brain and pituitary. Gonadosomatic index (GSI) and oocyte developmental stage were also investigated in the gonad based on anatomical- and histological observations. GSI value was significantly increased in the green spectrum-exposed group when compared to that of the other light-exposed groups (i.e., white, red, blue), with the presence of yolk stage oocytes (p˂0.05). The abundances of sbGnRHmRNA and fshβ mRNA in the green spectrum-exposed group were also significant higher than those of the other light spectra-exposed groups(p˂0.05). However, there was no significant difference between the abundances of lhβmRNA in all light spectra-exposed groups. These results indicate that the maturation of oocyte in grass puffercan be accelerated by exposure to the spectrum of green. The sbGnRHmRNA and fshβ mRNA may play an important reproductive parameters role in the initiation of maturation of oocyte. To better understand the molecular mechanism for the maturation of oocytein grass puffer, further study examining the relationship between oocyte development and its related genes (e.g., sbGnRHmRNA and fshβmRNA) is required.

Spermiation was stimulated in the mature grass puffer, Takifugu niphobles, with an injection of human chorionic gonadotropin (HCG) or carp pituitary extract (CPE). Spermatocrit and sperm density were reduced, but milt production was increased in both the HCG and CPE treatment groups relative to those in the control group (P < 0.05). These results should be useful for increasing the fertilization efficiency in grass puffer breeding programs.