| In this study, we investigated the effects of dietary protein level on energy and nitrogen budgets of juvenile Chinese soft-shelled turtle (Pelodiscus sinensis). Seven experimental diets (diet 1-7) were formulated to contain dietary protein levels of 25%, 27%, 29%, 31%, 33%, 35% (Low protein diets) and 43%(High protein diet).350 turtles with an average weight of 4.8g±0.7g were randomly distributed into 70 tanks. Turtles were fed one of the seven diets to satiation. 60 days later, the main results were shown as the following:1. There was no significant difference in SGR, feed coefficient and FCE among diet 5-7.The PER was significantly increased with the increase of dietary protein level, but diet 7 was significant lower than diet 5-6.2. The apparent digestibility coefficients (ADCs) of carbohydrate was significantly increased with the decline in dietary protein level. The low protein diets promoted the carbohydrate utilization.3. Dietary protein level was significantly effected the ratio of urine nitrogen and growth nitrogen to nitrogen intake. The minimum of the ratio of urine nitrogen to nitrogen intake was diet 5, the maximum of the ratio of urine nitrogen to nitrogen intake was diet 7; the growth of nitrogen to nitrogen intake was on the contrary. Assimilation efficiency of nitrogen was significantly higher in the low protein diets than the high protein diet. Although growth efficiency of nitrogen of diet 5 was higher than diet 6-7, there was no significant difference among them. Protein utilization rate in the low protein diets was hither than the high protein diet.And the nitrogen budgets of diet 1 -7 were as follow:Diet1: 100C = 12.72F + 48.51U + 38.77GDiet2: 100C = 11.08F + 40.69U + 48.23GDiet3: 100C = 8.95F + 39.97U + 51.08GDiet4: 100C = 9.25F + 40.30U + 50.45GDiet5: 100C = 8.22F + 37.48U + 54.30GDiet6: 100C = 8.16F + 41.37U + 50.47GDiet7: 100C = 6.48F + 50.95U + 42.57G... |
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