Effects of Dietary Yeast Extract Levels on Growth Performance, Digestibility and Antioxidant Capacity of the Taiwan Loach

Abstract

An 8-week feeding trial was conducted to determine the effects of different levels of dietary Yeast Extract (YE) on growth performance, digestibility and antioxidant capacity of the Taiwan loach. The trial contained 6 diets with different levels of wet YE, namely 0%, 1%, 2%, 3%, 4% and 5% (groups T1-T6). Each group contained 8 replicates with 12 loaches. Results indicated that the Specific Growth Rate (SGR) of loaches that were fed T5 diet were significantly higher than those of the other groups, whereas the feeding rate and feed conversion rate were just the opposite. The association of the regression analysis between different dietary YE and the loach SGR were: SGR=−9244YE3+622.03YE2-3.7768YE+3.9325(p<0.05). The apparent digestibility coefficient of the dry matter and the Amylase activity levels of the loaches fed with the YE were higher than those that were fed the T1 diet. The liver SOD activity was increased significantly following the increase in the YE supplementation (p<0.05). In conclusion, YE supplementation in the loach diet could promote growth, improve feed digestion and utilization, and enhance antioxidant capacity. The optimum levels of wet YE required for feeding the Taiwan loach species were estimated to 4.16%.