Effects of animal–plant protein ratio in extruded and expanded diets on nitrogen and energy budgets of juvenile Chinese soft-shelled turtle (Pelodiscus sinensis Wiegmann) |
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| Authors: | Yanju Jia Zhencai Yang Yujiang Hao & Yongli Gao |
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| Institution: | College of Life Science, Hebei Normal University, Shijiazhuang, Hebei, China; Laboratory of Evolution and Biogeography for Freshwater Fishes, Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan, China |
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| Abstract: | In this study, we investigated the effects of animal–plant protein ratio in extruded and expanded diets on nutrient digestibility, nitrogen and energy budgets of juvenile soft‐shelled turtle (Pelodiscus sinensis). Four extruded and expanded feeds (diets 1–4) were formulated with different animal–plant protein ratios (diet 1, 1.50:1; diet 2, 2.95:1; diet 3, 4.92:1; diet 4, 7.29:1). The apparent digestibility coefficients (ADCs) of dry matter and crude lipid for diet 1 were significantly lower than those for diets 2–4. There was no significant difference in crude protein digestibility among diets 1–4. The ADC of carbohydrate was significantly increased with the increase in animal–plant protein. Although nitrogen intake rate, faecal nitrogen loss rate and excretory nitrogen loss rate of turtles fed diet 1 were significantly higher than those fed diets 2–4, nitrogen retention rate, net protein utilization and biological value of protein in these turtles were significantly lower than those fed diets 2–4. In addition, energy intake rate, excretory energy loss rate and heat production rate of turtles fed diet 1 were also significantly higher than those fed diets 2–4. Faecal energy loss was significantly reduced with the increase in the animal–plant protein ratio. The ADC of energy and assimilation efficiency of energy significantly increased with a higher animal–plant protein ratio. The growth efficiency of energy in the group fed diet 1 was significantly lower than those in the groups fed diets 2–4. Together, our results suggest that the optimum animal–plant protein ratio in extruded and expanded diets is around 3:1. |
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| Keywords: | Pelodiscus sinensis animal–plant protein ratio extruded and expanded feed nitrogen budget energy budget |
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