臺灣五種養殖蝦的消化酵素活性比較

Comparision of Digestive Enzyme Activities of Five Species of Shrimps Cultured in Taiwan

莊健隆(Jan-Lung Chuang) ； 李孟芳(Meng-Fang Lee) ； 鄭健雄(Jan-Shyong Jenn)

《臺灣水產學會刊》 12卷2期 (1985/12) Pp. 43-53

https://doi.org/10.29822/JFST.198512.0004

摘要

本實驗係測定臺灣五種養殖蝦：草蝦(Penaeus monodon)、紅尾蝦(Penaeus penicillatus)、沙蝦(Metapenaeus monoceros)、斑節蝦(Penaeus japonicus)、淡水蝦(Macrobrachium rosenbergii)的消化酵素活性。這些酵素包括蛋白酶(protease)、α-澱粉酶(α-amylase)、纖維素酶(cellulase)、CM-纖維素酶(CM-cellulase)、藻膠酶(alginase)及幾丁質分解酶(chitinase)。並將其作一比較，以瞭解蝦消化飼料成分能力的强弱，進而提供在調配該等飼料時的參考。
實驗結果如下：
1.在蝦子的消化系統中，肝胰臟佔最高的重量百分率，且具有相當高的消化酵素活性，這些特點也許可以說明肝胰臟是消化酵素分泌及存在主要的器官。
2.五種蝦的肝胰臟、胃、腸，大都有蛋白酶、α-澱粉酶、及CM-纖維素酶活性的存在。纖維素酶及藻膠酶活性，在本試驗條件下，則在五種蝦中皆沒有測定到。
3.在淡水蝦、草蝦、斑節蝦等三種蝦中，每克蝦體重之蛋白酶總活性，隨著α-澱粉酶總活性的下降而有上升的趨勢。另外，它們的最適蛋白質需求量，與其每克體重所含蛋白酶總活性有正相關性，而與α-澱粉酶有負相關性。
4.紅尾蝦每克體重的蛋白酶總活性是五種蝦中最高者，甚至比斑節蝦還高；然而，其α-澱粉酶活性也僅次於淡水蝦，居第二高位。或許紅尾蝦對飼料中澱粉之利用力很强。
5.草蝦、紅尾蝦、沙蝦等三種蝦的蛋白酶最適活性溫度爲55℃，而淡水蝦則爲60℃，斑節蝦爲40℃。
6.澱粉酶最適活性溫度：草蝦50℃，紅尾蝦45~50℃，沙蝦40℃，淡水蝦45℃，斑節蝦40~45℃。

並列摘要

In Taiwan, the annual production of cultured shrimp has reached over 20,000 metric tons in 1984. The major aquacultural species is grass shrimp Penaeus monodon of which optimal salinity is 15‰. The heavy dependence on freshwater results in the limitation of further development of grass shrimp culture in Taiwan. To culture other species which can grow well in full-strength seawater is an alternative under this situation. Thus, to formulate feed for the shrimp other than grass shrimp is urgent. The digestive enzyme activities reflect aquatic animals' feeding habit and correlate with their ability to utilize different feed ingredients. Therefore, to study the activities of different digestive enzymes of a species of shrimp may give clue in formulating adequate feed for that animal.
Five species of shrimps (Table 1) namely grass shrimp (Penaeus monodon), red-tail shrimp (Penaeus penicillatus), sand shrimp (Metapenaeus monoceros), kuruma shrimp (Penaeus japonicus) and freshwater prawn (Macrobrachium rosenbergii) were used to study their digestive enzyme activities. Tissues including hepatopancreas, stomach and intestine were sampled. The digestive enzymes assayed include protease (caseinolyticactivity), α-amylase, CM-cellulase, cellulase, aginase and chitinase.
The relative weight ratios of hepatopancreas of all the five species are much higher than those of intestine and stomach of the corresponding species (Fig.1). In addition, specific activities of the digestive enzymes are found higher in hepatopancreas than in the other tissues (Figs. 2, 3 and 4). These facts suggest that hepatopancreas may be a very important organ for producing and secreting digestive enzymes.
Although CM-cellulase activities are observed in most tissues (especially hepatopancreas and stomach) of all the five species of shrimps, cellulase activities are not detected in all the tissues of all the shrimps. Neither alginase activities are detected in all the shrimps studied.
In comparing the caseinolytic activities and α-amylase activities of freshwater prawn, grass shrimp and kuruma shrimp whose dietary protein requirement are well understood (Table 2.), it seems that the quantity of protein required increases as caseinolytic activity increases and as the α-amylase activity decreases. In view of the protease activity alone, it seems contradictory that sand shrimp has relatively low caseinolytic activity (Fig.6) yet relatively high protein requirement (55% crude protein) in its diet (Table 2.). However, if low α-amylase activity of sand shrimp is also taken into consideration, the above puzzle may be clarified.
It is of interest to find that red-tail shrimp has highest caseinolytic activity and relatively high α-amylase activity. This suggests that the shrimp may be able to efficiently utilize both protein and starch.
Optimum temperature of α-amylase and caseinolytic activities of all the five species are also reported (Fig. 8, 9) in this study.