Effects of dietary protein on water quality, growth performance, RNA/DNA ratio and haemato-immunological indices of soft-shelled turtle (Pelodiscus sinensis). Issue 123 (April 2022)

• Record Type: Journal Article
• Authors: Kou, Hongyan; Hu, Junru; Wang, An-Li; Pan, Xunbin; Vijayaraman, Sarath Babu; Miao, Yutao; Lin, Li
• Is Part Of: Fish & shellfish immunology. Issue 123(2022)
• Page Start: 127
• Page End: 135
• Publication Date: 2022-04
• Subjects: Soft-shelled turtle -- Protein requirement -- Hematological parameters -- Water quality -- Immunological parameters; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2022.02.027
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: In aquatic animals, dietary protein plays a crucial role in their growth and immunity. A feeding trial was conducted on soft-shelled turtles ( Pelodiscus sinensis ) to assess the effects of various levels of protein on the specific growth rate (SGR), ambient water quality (total ammonia nitrogen (TAN), total nitrogen (TN) and total phosphorus (TP)), hematological parameters (respiratory burst (RB), red blood cell count (RBC), albumin content (Alb), hemoglobin level (Hb) and osmolality), plasma immunoglobulin M (IgM) levels and lysozyme activity. Soft-shelled turtles weighing about 4.02 g were fed fish meal-based diets with 14.38%, 20.41%, 26.19%, 32.23%, 37.63% and 45.23% protein for 8 weeks. SGR, RBC, Hb, Alb, RB, IgM and lysozyme activity were enhanced as the dietary protein was increased from 14.38% to 26.19%, then reached a plateau. For identical feeding times, TAN and TN were increased with elevating dietary protein levels. While, no statistically significant differences were observed among the 26.19%, 32.23% and 37.63% groups. When the turtles were cultivated for 56 days and fed with 45.23% protein, the TP in the culturing water was higher than that in the other groups. An increase in dietary protein level up to 26.19% increased the RNA/DNA ratio, which subsequently plateaued at a steady level. The levels of dietary protein had no impact on osmolality or alkaline phosphatase (AKP) activity. On the basis of broken-line analyses derived from SGR, the optimum dietary protein level for soft-shelled turtles was found to be 27.11% protein. Highlights: Optimum dietary protein level for soft-shell turtles was 27.11% protein, based on broken-line analyses derived from SGR. Optimum protein level improved the specific growth rate. Optimum protein level enhanced hematological indicators (respiratory burst, red blood cells, albumin, and hemoglobin). Optimum protein level increased Ig M, lysozyme activity, and the RNA/DNA ratio. Total ammonia nitrogen and total nitrogen were elevated with increasing dietary protein levels.