Assessing the efficacy of three methionine sources in low protein and low fish meal diet for Chinese soft-shelled turtle, Pelodiscus sinensis

作者：Zhou, Fan^*; Wang, Ya-Qin; Bei, Yi-Jiang; Ng, Wing-Keong; Wang, Ding-Nan; Li, Shi-Yan; Meng, Qing-Hui; Ding, Xue-Yan

来源：Aquaculture International, 2018, 26(1): 15-26.

DOI：10.1007/s10499-017-0193-3

• Pelodiscus sinensis
• Methionine sources
• Growth
• Body composition
• Antioxidant enzymes

An 8-week feeding trial was conducted to evaluate the effects of three dietary methionine (Met) sources [DL-Met, coated-Met, and a methionine hydroxy analogue calcium salt (MHA-Ca)] for Chinese soft-shelled turtle (Pelodiscus sinensis). Triplicate groups of juvenile turtles (initial weight 3.48 +/- 0.03 g) were fed twice per day at 3% of body weight with positive control diet (T1, 46% protein and 46% fish meal, FM), negative control diet (T2, 43% protein and 23% FM), or three other test diets supplemented with either 0.2% coated-Met (T3), 0.125% MHA-Ca (T4), or 0.1% DL-Met (T5) to the T2 basal formulation, respectively. The feeding trial was conducted in 15 350-L plastic containers with three replicates per dietary treatment. The results showed that the highest and lowest percentage weight gain (1023.5 +/- 18.2 versus 882.1 +/- 14.5%) and feed efficiency (87.2 +/- 0.94 versus 81.4 +/- 0.4%) were observed in turtles fed the T1 and T2 diet (P < 0.05), respectively. Significant improvement in weight gain was observed in turtles fed diets with Met supplementation, irrespective of source, compared with turtles fed the T2 diet. It was observed that dietary MHA-Ca had similar efficacy compared with DL-Met in terms of growth performance and feed utilization efficiency of the turtles (P > 0.05). Protein utilization efficiency was significantly higher in turtles fed T4 or T5 diet compared to the T2 diet. Whole body protein content (17.0 to 17.4% on a wet weight basis) in turtles fed with Met-added diets was comparable to those of turtles fed the T1 diet which were significantly higher compared to T2-fed turtles. Antioxidant defense system enzymes, superoxide dismutase, and glutathione peroxidase showed the highest activity, 658.8 +/- 17.9 U/mL and 642.8 +/- 17.5 mu mol/L, respectively, in the serum of turtle fed the MHA-Ca supplemented diet and was significantly higher compared to turtles fed the T2 or T3 diet. The present results showed that P. sinensis are able to effectively use added MHA-Ca and DL-Met in low protein and low FM diets to enhance growth, feed utilization efficiency, nitrogen retention, and antioxidant defense system enzyme activities.

• 出版日期2018-2
• 单位浙江大学