Liu Yu, Fan Jiongting, Huang Huajing, Zhou Hang, Cao Yixiong, Zhang Yumeng, Jiang Wen, Zhang Wei, Deng Junming, Tan Beiping
College of Fisheries, Guangdong Ocean University, Zhanjiang, China.
Aquatic Animals Precision Nutrition and High Efficiency Feed Engineering Research Centre of Guangdong Province, Zhanjiang, China.
Front Nutr. 2022 Oct 26;9:1015371. doi: 10.3389/fnut.2022.1015371. eCollection 2022.
An 8-weeks feeding trial was carried out to evaluate the effects of different levels of dietary non-starch polysaccharide on the growth, apparent nutrient digestibility, intestinal development, and morphology of largemouth bass (). Seven isoproteic and isolipidic experimental diets were formulated (crude protein 47.00%, crude lipid 12.50%), containing 0, 3, 6, 9, 12, 15, and 18% non-starch polysaccharides (NSPs) (named Control, NSPs3, NSPs6, NSPs9, NSPs12, NSPs15, and NSPs18), respectively. Dietary inclusion of NSPs below 9% showed no negative impacts on fish growth and feed utilization efficiency, whereas dietary NSPs inclusion level above 9% decreased weight gain rate, specific growth rate, protein efficiency, protein deposition rate, apparent digestibility of dry matter and protein, and were accompanied by a reduction in intestinal protease, Na/K-ATPase and alkaline phosphatase activity and an increase in feed intake and feed coefficient. The activity of lipase was significantly decreased when dietary inclusion of 15 and 18% NSPs. Moreover, the lipid deposition rate and the apparent digestibility of lipids were significantly decreased since dietary inclusion of 9% NSPs. Dietary inclusion of NSPs above 12% significantly up-regulated intestinal GLP-2 gene's expression, and was accompanied by significant changes in hindgut morphology, including increases in villus length and width, muscularis thickness and number of goblet cell, as well as a decrease in crypt depth. Additionally, dietary inclusion of NSPs above 3% significantly increased intestinal length index, and the viserosomatic index was significantly increased when dietary NSPs exceeded 15%. The linear regression analysis based on weight gain rate and feed coefficient showed that the appropriate dietary NSPs level of juvenile largemouth bass should not above 5.51%. In conclusion, high dietary NSPs adversely affects digestive enzyme activity and intestinal morphology, which in turn reduced the apparent digestibility of dietary nutrients and growth of juvenile largemouth bass.
进行了为期8周的饲养试验，以评估不同水平的日粮非淀粉多糖对大口黑鲈生长、表观养分消化率、肠道发育和形态的影响。配制了七种等蛋白、等脂肪的实验日粮（粗蛋白47.00%，粗脂肪12.50%），分别含有0、3、6、9、12、15和18%的非淀粉多糖（NSPs）（分别命名为对照、NSPs3、NSPs6、NSPs9、NSPs12、NSPs15和NSPs18）。日粮中NSPs含量低于9%对鱼类生长和饲料利用效率无负面影响，而日粮中NSPs含量高于9%则会降低增重率、特定生长率、蛋白质效率、蛋白质沉积率、干物质和蛋白质的表观消化率，并伴随着肠道蛋白酶、Na/K - ATP酶和碱性磷酸酶活性的降低以及采食量和饲料系数的增加。当日粮中NSPs含量为15%和18%时，脂肪酶活性显著降低。此外，自日粮中NSPs含量为9%起，脂质沉积率和脂质表观消化率显著降低。日粮中NSPs含量高于12%显著上调肠道GLP - 2基因的表达，并伴随着后肠形态的显著变化，包括绒毛长度和宽度增加、肌层厚度增加、杯状细胞数量增加以及隐窝深度减小。此外，日粮中NSPs含量高于3%显著增加肠道长度指数，当日粮中NSPs超过15%时，脏体比显著增加。基于增重率和饲料系数的线性回归分析表明，大口黑鲈幼鱼日粮中合适的NSPs水平不应高于5.51%。总之，日粮中高含量的NSPs会对消化酶活性和肠道形态产生不利影响，进而降低日粮养分的表观消化率和大口黑鲈幼鱼的生长。
