Wang Yue, Geng Yiran, Shi Xueying, Wang Siqi, Yang Zhencai, Zhang Peiyu, Liu Haiyan
Laboratory of Aquatic Animal Nutrition and Ecology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China.
Animals (Basel). 2022 Nov 10;12(22):3101. doi: 10.3390/ani12223101.
A 60-day feeding trial was performed to assess the effects of dietary phosphorus levels on growth performance, body composition, phosphorus utilization, plasma physiological parameters and intestinal Ca and P transport-related gene expression of juvenile Chinese soft-shelled turtle (. ). Four diets containing available P at graded levels of 0.88%, 1.00%, 1.18% and 1.63% (termed as D0.88, D1.00, D1.18 and D1.63, respectively) were formulated and each diet was fed to turtles (5.39 ± 0.02 g) in sextuplicate. The turtles were randomly distributed to 24 tanks with 8 turtles per tank. The results indicated that final body weight, specific growth rate, feed conversion ratio and protein efficiency ratio performed best in turtles fed 1.00% available P diet. The crude lipids of the whole body exhibited a decreasing trend with the dietary available P, whereas the calcium and phosphorus of the whole body and bone phosphorus showed an opposite tendency. The apparent digestibility coefficient of phosphorus declined with the dietary available P. Turtles fed 1.00% available phosphorus had the highest phosphorus retention ratio compared with other treatments. Simultaneously they had significantly lower phosphorus loss than turtles fed D1.18 and D1.63 and had no differences in this respect from turtles fed a low-phosphorus diet. It was noteworthy that the lowest plasma calcium concentrations, and alkaline phosphatase activities in plasma and liver, were discovered in turtles fed the diet containing 1.63% available phosphorus. In addition, the high-phosphorus diet resulted in significantly down-regulated expression of intestinal phosphorus and calcium transport-related key genes. In conclusion, the available phosphorus requirement of juvenile . was determined at 1.041% (total phosphorus was 1.80%) based on quadratic regression of weight gain rate, and excessive dietary phosphorus stunted turtle growth possibly via inhibiting intestinal calcium absorption.
进行了为期60天的饲养试验，以评估日粮磷水平对中华鳖幼鳖生长性能、体成分、磷利用率、血浆生理参数以及肠道钙和磷转运相关基因表达的影响。配制了四种日粮，其有效磷水平分别为0.88%、1.00%、1.18%和1.63%（分别称为D0.88、D1.00、D1.18和D1.63），每种日粮以六重复的方式投喂给体重为（5.39±0.02）g的鳖。将鳖随机分配到24个养殖池中，每个养殖池8只鳖。结果表明，投喂1.00%有效磷日粮的鳖，其终末体重、特定生长率、饲料转化率和蛋白质效率比表现最佳。鳖体粗脂肪含量随日粮有效磷水平的升高呈下降趋势，而鳖体钙、磷含量以及骨磷含量则呈相反趋势。磷的表观消化率系数随日粮有效磷水平的升高而降低。与其他处理组相比，投喂1.00%有效磷日粮的鳖的磷保留率最高。同时，其磷损失显著低于投喂D1.18和D1.63日粮的鳖，且在这方面与投喂低磷日粮的鳖无差异。值得注意的是，投喂含1.63%有效磷日粮的鳖，其血浆钙浓度最低，血浆和肝脏中的碱性磷酸酶活性也最低。此外，高磷日粮导致肠道磷和钙转运相关关键基因的表达显著下调。综上所述，基于增重率的二次回归分析，确定中华鳖幼鳖的有效磷需求量为1.041%（总磷为1.80%），日粮磷过量可能通过抑制肠道钙吸收而阻碍鳖的生长。
