경구투여 $\beta$-glucan이 잉어와 넙치의 비특이적 면역활성에 미치는 영향

Effects of $\beta$-glucan from Schizophillum commune on Non-specific Immune Parameters in Common Carp (Cyprinus carpio) and Flounder (Paralichthys olivaceus) by Oral Administration

[ $\beta$ ]-glucan을 시판의 배합사료에 $0.1\%$ 첨가한 다음 담수어인 잉어 (평균체중 1.0g 및 68.7g)와 해산어인 넙치 (평균 체중, 12.1 g 및 54.0g)에 2주간 첨가사료, 1주간 무첨가사료, 2주간 첨가사료 투여의 투여방법으로 5주간 경구투여한 다음 인위감염에 대한 생잔율을 조사하였다. 또 투여기간중의 말초혈액의 백혈구수와 혈중리소자임의 활성과 5주간 투여후에 채취한 백혈구의 식작용능을 조사하였다. $\beta$-glucan첨가사료 투여군에 $1\times10^6$cells의 Aeromonas hydrophila를 접종한 평균체중 68.7g의 잉어군과 $1\times10^5$cells의 Edwardsiella tarda를 접종한 평균체중 68.7g의 넙치군에서 $\beta$-glucan첨가사료 투여군이 무첨가투여군에 비해 생존율이 높았고 (P<0.05),그 외의 접종군에서는 무첨가투여군과 차이가 없었다. $\beta$-glucan첨가사료 투여기간 동안 말초혈액중의 마크로파아지와 호중구수는 투여기간에는 증가, 무투여기간에는 감소하는 경향이었으며 특히 마크로파아지의 증가가 현저하였다. 혈중 리소자임은 잉어에서는 $\beta$-glucan첨가사료 투여기간에는 상승하고 무투여기간에는 감소하였지만, $\beta$-glucan첨가사료를 다시 투여한 후 급격히 상승하여 높은 활성을 유지하였다 그러나 넙치는 잉어보다는 활성의 증가는 현저하지 않았고 무투여기간에도 변동이 없었지만 무첨가투여군보다는 항상 높은 활성을 나타내었다.

The effects of dietary $\beta$-glucan administration on non-specific immune parameters in common carp, Cyprinus carpio, (1.0 g and 68.7 g of body weight) and flounder, Paralichthys olivcaces (12.1 g and 54.0 g of body weight) were evaluated. All fishes were fed an experimental diet supplemented with $\beta$-glucan at $0.1\%$ per kg diet for 5 weeks. A week intermission with basal diet occurred between first 2 weeks and second 2 weeks of $\beta$-glucan administration, The changes in the numbers of peripheral neutrophils and macrophages were counted under light microscopy and serum lysozyme activity was also analysed at a week of interval during the experiment. Phagocytic activities of leucocytes from the swimm bladder of carp and the peritonium of flounder were measured 5 weeks after feeding. The oral adminisration of $\beta$-glucan induced significant reduction in mortality after an artificial challenge with $1\times10^6$ cells of Aeromonas hydrophila in larger carp and $1\times10^5$ cells of Edwardsiella tarda in larger flounder but did not in other groups. The numbers of peripheral macrophages and neutrophils, phagocytic acitivies of leucocytes, and the activity of serum lysozyme were greatly increased in the fish fed a $\beta$-glucan supplemented diet. These suggest that $\beta$-glucan administration by oral route can enhance leucocyte phagocytic activity, serum lysozymal activity, and survival rate against artificial infections depending on the infected fish size and challenged bacterial concentration.