Debnath D, Pal A K, Sahu N P, Yengkokpam S, Baruah K, Choudhury D, Venkateshwarlu G
Department of Fish Nutrition and Biochemistry, Central Institute of Fisheries Education, Fisheries University Road, Versova, Mumbai-400 061, India.
Comp Biochem Physiol B Biochem Mol Biol. 2007 Jan;146(1):107-14. doi: 10.1016/j.cbpb.2006.09.008. Epub 2006 Oct 14.
Labeo rohita, commonly called rohu is one of the most important fish species for aquaculture in India. Digestive enzyme response and metabolic profile of fingerling L. rohita to different dietary crude protein (CP) levels (viz. 25, 30, 35 and 40%) were studied in an attempt to optimize a practical diet formulation for this species. After 45 days of feeding, activity of digestive enzymes and metabolite concentrations were assayed. Amylase, lipase and alkaline phosphatase (ALP) activities were not influenced by the dietary protein, but proteolytic and acid phosphatase (ACP) activities varied (P<0.05) between the treatments. Proteolytic activity showed a second order polynomial relationship with dietary crude protein (CP) as Y = 0.0734X(2) + 4.937X - 68.37, r(2)=0.97. A positive correlation was observed between dietary CP and amylase (r(2)=0.78). All the metabolites except muscle glucose showed significant change corresponding to the dietary protein levels. Glucose and glycogen levels corresponded to the dietary carbohydrate levels. Muscle and plasma pyruvic acid increased as the crude protein in the diet increased, whereas liver pyruvic acid showed the opposite trend. Muscle protein content was not affected by dietary CP. Protein fractions in plasma (total protein, albumin and globulin) showed maximum values in 30% CP fed group. It is concluded that proteolytic activity and ACP are the major digestive enzymes responsive to dietary CP in L. rohita fingerlings. Considering the cost effectiveness of the diet, and based on liver and plasma free amino acid levels and plasma protein fractions, 30% crude protein is recommended as the optimal dietary protein for L. rohita fingerlings.
印度魮，通常被称为露斯塔野鲮，是印度水产养殖中最重要的鱼类品种之一。为了优化该品种的实用饲料配方，研究了印度魮幼鱼对不同饲料粗蛋白（CP）水平（即25%、30%、35%和40%）的消化酶反应和代谢概况。投喂45天后，测定消化酶活性和代谢物浓度。淀粉酶、脂肪酶和碱性磷酸酶（ALP）活性不受饲料蛋白质的影响，但不同处理间的蛋白水解酶和酸性磷酸酶（ACP）活性存在差异（P<0.05）。蛋白水解酶活性与饲料粗蛋白（CP）呈二次多项式关系，即Y = 0.0734X² + 4.937X - 68.37，r² = 0.97。饲料CP与淀粉酶之间存在正相关（r² = 0.78）。除肌肉葡萄糖外，所有代谢物均随饲料蛋白质水平发生显著变化。葡萄糖和糖原水平与饲料碳水化合物水平相对应。随着饲料中粗蛋白含量的增加，肌肉和血浆丙酮酸含量升高，而肝脏丙酮酸含量则呈相反趋势。肌肉蛋白质含量不受饲料CP的影响。血浆中的蛋白质组分（总蛋白、白蛋白和球蛋白）在投喂30%CP饲料的组中显示出最大值。研究得出结论，蛋白水解酶活性和ACP是印度魮幼鱼中对饲料CP有反应的主要消化酶。考虑到饲料的成本效益，并基于肝脏和血浆游离氨基酸水平以及血浆蛋白组分，建议30%的粗蛋白作为印度魮幼鱼的最佳饲料蛋白。
