School of Environment and Natural Resources, The Ohio State University, Columbus, OH 43210, USA.
J Anim Physiol Anim Nutr (Berl). 2010 Feb 1;94(1):35-43. doi: 10.1111/j.1439-0396.2008.00877.x. Epub 2009 Nov 11.
We have shown previously that diets in which the nitrogen portion is based on synthetic dipeptides (PP) resulted in weight gain by rainbow trout alevins when free amino acid (FAA) based diets did not. However, the protein-based diet used as a control in the previous study resulted in a significantly better performance of fish than peptide- or FAA based diet fed fish. Therefore, the objectives of our study were (i) to test how stomachless fish respond to peptide-based diets, (ii) to evaluate PP and protein-PP mixture diets and (iii) to examine if post-prandial response to FAA concentrations in the fish body can be used as an indicator of the availability of dietary amino acid sources. The first experiment was conducted with a 4-day old Koi carp (Cyprinus carpio) larvae and included groups fed a casein-gelatin (CG) based diet, a commercial diet and live Artemia nauplii. In the second experiment, fish fed live Artemia for 3 weeks (69 +/- 12 mg) were placed in glass aquaria in triplicate per dietary treatment. Four diets provided equivalent amounts of nitrogen in the form of a CG, a PP, a 50% PP and 50% CG (PP50) mix and as FAA. Fish were fed at 1 and 3 h intervals, and the survival and growth were monitored during the second and third weeks of experiments 1 and 2 respectively. Following the completion of feeding, juvenile carp were sampled prior to feeding and 3 h after a meal. Whole body FAA analyses were carried out. We observed marginal suitability of the CG diet for larval Koi carp, as earlier indicated in common carp. Juvenile Koi carp fed the CG diet achieved 236 +/- 19 mg, whereas PP50, PP and FAA diet fed fish grew to 140 +/- 37, 70 +/- 8 and 73 +/- 5 mg respectively. Free amino acids in the fish body, and in particular indispensable amino acids (IDAA), were excellent indicators of dietary availability. The present experiment shows that a dietary 1:1 ratio of protein to synthetic PPs results in better growth, survival and whole body IDAA concentrations in relation to FAA- and PP-based diets confirming earlier reports on the use of synthetic PP-based diets, although this diet does not match the performance of complete protein, CG-based diet.
我们之前已经证明，当基于游离氨基酸（FAA）的饮食不能使虹鳟幼鱼增重时，基于合成二肽（PP）的氮部分的饮食会使它们增重。然而，在之前的研究中用作对照的基于蛋白质的饮食使鱼类的表现明显优于基于肽或 FAA 的饮食喂养的鱼类。因此，我们研究的目的是：（i）测试无胃鱼类对基于肽的饮食的反应；（ii）评估 PP 和蛋白质-PP 混合物饮食；（iii）检查鱼类体内 FAA 浓度的餐后反应是否可用作饮食氨基酸来源可用性的指标。第一项实验是用 4 天大的锦鲤（Cyprinus carpio）幼鱼进行的，包括喂食酪蛋白-明胶（CG）基础饮食、商业饮食和活丰年虾的各组。在第二项实验中，用活丰年虾喂养 3 周（69 +/- 12 mg）的鱼被放置在每个饮食处理的三重复玻璃水族箱中。四种饮食以 CG、PP、50%PP 和 50%CG（PP50）混合物和 FAA 的形式提供等量的氮。鱼在 1 小时和 3 小时间隔喂食，在实验 1 和 2 的第二和第三周分别监测生存和生长情况。在完成喂食后，在喂食前和饭后 3 小时采集幼鱼样本。进行了全身 FAA 分析。我们观察到 CG 饮食对锦鲤幼鱼的适度适宜性，这与鲤鱼早期的结果相似。以 CG 饮食喂养的幼鱼体重达到 236 +/- 19 mg，而以 PP50、PP 和 FAA 饮食喂养的鱼体重分别达到 140 +/- 37、70 +/- 8 和 73 +/- 5 mg。鱼体内的游离氨基酸，特别是必需氨基酸（IDAA），是饮食可利用性的极好指标。本实验表明，饮食中蛋白质与合成 PP 的 1:1 比例可促进生长、生存和全身 IDAA 浓度，与基于 FAA 和 PP 的饮食相比，这证实了之前关于使用合成 PP 饮食的报告，尽管这种饮食与完整蛋白质 CG 基础饮食的性能不匹配。
