Dietary lysine requirement of adult lambari ( Astyanax altiparanae ) (Garutti and Britski, 2000)

ABSTRACT A 90-day feeding trial was conducted to estimate the dietary lysine requirement of adult lambari ( Astyanax altiparanae ), based on growth performance, whole-body composition, muscle development, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. Six isoproteic (345.0 g kg−1) and isoenergetic (19.51 MJ kg−1) diets were formulated, and crystalline L-lysine was added to obtain diets with lysine concentrations of 12.13, 13.31, 15.36, 18.79, 19.92, and 23.02 g kg−1 dry diet. Female adult lambari (n = 480; weight of 4.96±0.02 g) were distributed into 24 (70 L) aquaria and fed the experimental diets six times daily. Fish fed 12.13 to 19.92 g kg−1 lysine showed increased weight gain and percent weight gain, and fish from those treatments also showed improvement in final carcass quality by a decrease in whole-body lipid content. Fish fed 12.13 g kg−1 lysine showed lower ALT and AST activities in blood serum when compared with fish fed the highest lysine levels. No differences were observed in muscle growth in fish fed graded lysine levels. According to the broken-line model analysis of weight gain and dietary lysine levels, the dietary lysine requirement of adult lambari is estimated at 18.72 g kg−1 (5.41% of dietary protein).

摘要 本研究开展了一项为期90天的饲喂试验，旨在基于生长性能、全鱼体成分、肌肉发育以及天冬氨酸氨基转移酶（aspartate aminotransferase，AST）和丙氨酸氨基转移酶（alanine aminotransferase，ALT）活性，评估成年高体脂鲤（Astyanax altiparanae）的日粮赖氨酸需求量。本研究配制了6组等蛋白质（345.0 g kg⁻¹）、等能量（19.51 MJ kg⁻¹）的基础日粮，通过添加结晶L-赖氨酸，使各日粮的赖氨酸浓度分别达到12.13、13.31、15.36、18.79、19.92和23.02 g kg⁻¹干日粮。选取初始体重为4.96±0.02 g的成年雌性高体脂鲤480尾，随机分配至24个70 L的水族箱中，每日饲喂6次实验日粮。饲喂12.13~19.92 g kg⁻¹赖氨酸日粮的试验鱼，其增重和增重率均显著提升，且该处理组试验鱼的全鱼体脂质含量降低，终末胴体品质得到改善。饲喂12.13 g kg⁻¹赖氨酸日粮的试验鱼，其血清中天冬氨酸氨基转移酶和丙氨酸氨基转移酶活性显著低于饲喂最高赖氨酸水平日粮的试验鱼。不同梯度赖氨酸水平对试验鱼的肌肉生长无显著影响。基于增重率与日粮赖氨酸水平的折线模型分析，本研究估算得到成年高体脂鲤的日粮赖氨酸需求量为18.72 g kg⁻¹（占日粮蛋白质的5.41%）。