(Background) Manganese (Mn) is an essential mineral, although its effects on rabbits is not clear. (Research Purpose) This study was conducted to investigate the effects of the level of supplementation of dietary manganese on growth performance, blood biochemistry, nitrogen metabolism and skeletal development of growing Rex rabbits. (Methods) Two hundred 3-month-old healthy Rex rabbits with similar body weights were randomly divided into 5 groups (A, B, C, D, E), with 40 replicates in each group. The rabbits in the 5 groups were fed a basal diet containing 0, 5, 10, 20 and 40 mg/kg manganese (in the form of manganese sulfate), respectively. The trial included 7 days for adaptation and 29 days of testing. Seven days before the end of feeding, eight rabbits from each group were transferred into a metabolic cage for metabolic testing. (Results) The results showed that supplemental dietary manganese levels did not significantly influence final body weight (FBW) or average daily feed intake (ADFI) (P＞0.05). Average daily gains (ADG) were significantly higher in the 20 mg/kg manganese group than in the other groups, and the ratio of feed to body weight gain (F/G) was significantly affected by manganese level (P < 0.05). No significant differences were found in the digestion coefficients among the groups (P > 0.05). Regarding carcass traits, the thymus index and total fat were significantly different (P < 0.05) among the groups, but there were no other significant differences (P > 0.05). The addition of manganese had no significant effect on the intake of nitrogen (IN), fecal nitrogen (FN), digestible nitrogen (DN) or the apparent digestibility of nitrogen (NAD). Compared to the other groups, urinary nitrogen (UN) was lower in the 20 mg/kg group, although nitrogen deposition (RN), nitrogen utilization (NUR) and the biological potency of nitrogen (NBV) were higher in this group (P < 0.05). As the amount of manganese added to the diet increased, serum triglycerides decreased (P < 0.05). Serum Mn-SOD was significantly lower in the 5 mg/kg manganese group than in the other groups (P < 0.05). The results of this study demonstrate that a diet with supplemented manganese can improve Rex rabbit growth performance and increase RN, NUR and NBV. There were no significant effects of different dietary levels of Mn on the ratio of bone to meat (P > 0.05) or bone strength (P < 0.05). (Conclusion) In conclusion, we determined that the optimal level of manganese supplementation in the diet of growing Rex rabbits was 20 mg/kg, which was also found to reduce nitrogen emissions into the environment.

中文翻译：

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补充锰饮食对獭兔生长性能，血液生化，氮代谢和骨骼发育的影响。

（背景）锰（Mn）是必需的矿物质，尽管它对兔子的影响尚不清楚。（研究目的）本研究旨在研究膳食锰的添加水平对Rex家兔生长性能，血液生化，氮代谢和骨骼发育的影响。（方法）将200只3个月大，体重相似的健康獭兔随机分为5组（A，B，C，D，E），每组40只。分别给5组兔子饲喂基础饮食，其中分别含0、5、10、20和40 mg / kg锰（以硫酸锰的形式）。该试验包括适应性7天和测试29天。喂食结束前七天，将每组八只兔子转移到代谢笼中进行代谢测试。（结果）结果表明，膳食中补充锰水平对最终体重（FBW）或平均日采食量（ADFI）没有显着影响（P＞ 0.05）。20 mg / kg锰组的平均日增重（ADG）明显高于其他各组，并且锰水平显着影响饲料与体重增重的比例（F / G）（P <0.05）。各组之间的消化系数没有显着差异（P> 0.05）。关于car体性状，各组之间的胸腺指数和总脂肪差异显着（P <0.05），但其他差异无统计学意义（P> 0.05）。锰的添加对氮（IN），粪便氮（FN），可消化氮（DN）或表观氮消化率（NAD）的摄取没有显着影响。与其他组相比，20 mg / kg组的尿中氮（UN）较低，尽管该组中的氮沉降（RN），氮利用率（NUR）和氮的生物效价（NBV）较高（P < 0.05）。随着饮食中锰含量的增加，血清甘油三酸酯减少（P <0.05）。5 mg / kg锰组的血清Mn-SOD显着低于其他组（P <0.05）。这项研究的结果表明，添加锰的饮食可以改善獭兔的生长性能并增加RN，NUR和NBV。不同饮食水平的锰对骨肉比（P> 0.05）或骨强度（P <0.05）没有显着影响。（结论）总而言之，