不同养殖模式下尼罗罗非鱼消化酶活性的比较

Comparison of the digestive enzyme activity of Nile tilapia (Oreochromis niloticus) in different farming modes

以广东省3种较常见的罗非鱼养殖模式作为实验对象,开展养殖模式对尼罗罗非鱼消化酶活性影响的研究,旨在阐明养殖模式中水温、饲料成分等因素对消化酶活性的影响。实验中养殖模式分别为传统养殖模式(M1),一年两造养殖模式(M2),鱼虾混养养殖模式(M3)。养殖中定期进行水质测定,4次取样并运用生化法测定消化酶活性。3种模式酶活性比较结果发现,M2的胃总蛋白酶活性最高,M1肠总蛋白酶活性最高;3种养殖模式总蛋白酶活性趋势都是肠总蛋白酶>胃总蛋白酶>肝胰脏总蛋白酶。M2的肠总脂肪酶、肠总淀粉酶、肝胰脏总脂肪酶活性和肝胰脏总淀粉酶活性总体高于其他两种模式,同时,饲料系数总体低于其他两种模式。研究表明,罗非鱼不同脏器的蛋白消化能力不同,以肠道最强;3种养殖模式总体蛋白消化酶活性无显著性差异;M2对脂肪及淀粉的消化能力较强,可减少尼罗罗非鱼对蛋白的需求量,降低饲料系数,从而降低饲料成本达到增收的目的。

To understand the impact of farming mode on digestive enzyme activity of tilapia, we selected three familiar breeding patterns in Guangdong province,i, e. traditional farming mode（ M1 ）, twice harvest a year farming mode （M2） and polyculture of fish and shrimp farming mode （M3）. We performed water quality monitoring and digestive enzyme activity detection through the four months observation. M2 model showed the highest stomach protease activity （SPA）in both 1st and 2na months. M1 mode displayed the highest intestinal protease activity （IPA） during the whole observation period. For the hepatopancreas protease activity （HPPA）, M2 mode was rather high in the 2＂d month as well as the 3rdmonth, while M3 model showed the highest level in both l^t and 4＇h months. In terms of each model, the protease activity displayed in the order of IPA 〉 SPA 〉 HPPA. Lipase activity and amylase activity of intestine and hepatopancreas were overall highest in M2 mode. The ability of protein digestion of tilapia in different organs is different, but no significant difference for total protein digestion ability among the three breeding patterns. On the other hand, M2 mode showed advantage in digestion of fat and starch which would reduce the demand of protein in feed composition and further improve the feed conversion ratio and cut down the cost of feed.