The aim of this study was as follows:1)to investigate the effects of graded levels of N-carbamylgluta-mate(NCG)on performance,blood biochemical indexes,carcass traits and related indicators in growing-finishing pigs,and 2)to determine the optimal supplemental level.The toxicity of high-dose(much higher than recommended levels)NCG was assessed by routine blood tests and blood biochemical and histopathologic examinations of the heart,liver,spleen,lung,kidney and stomach.One hundred and forty-four growing-finishing pigs(Duroc×Large White×Landrace,32.24±1.03 kg)were used in a 74-d experiment and each treatment was replicated 6 times with 4 pigs(2 barrows and 2 gilts)per replicate.The dietary treatments were a corn-soybean meal basal diet supplemented with 0％(control),0.05％,0.1％,0.15％,0.2％or 1％NCG.The first 5 groups were used to explore the optimal supplemental level of NCG,while the control,0.1％and 1％NCG groups were used to explore the safety of high-dose NCG.Compared with the normal control group,the final body weight and average daily gain tended to be higher in the 0.1％group(P=0.08),the lean percentage tended to be higher in the 0.05％group(P=0.07),the levels of free amino acids in the blood significantly increased in the 0.1％group(P＜0.05),both 0.1％and 0.15％NCG supplementation increased the levels of nitric oxide(NO)in serum(P=0.07)and muscle growth-and lipid metabolism-related gene expression(P＜0.05)and NCG supplementation improved C18:1N9C monounsaturated fatty acids(MUFA)in a dose-dependent manner(P=0.08).In addition,routine blood tests,blood biochemical indexes and histopathological examination revealed no abnormalities.Overall,increasing the levels of NCG did not linearly improve the above indicators;the 0.1％dose showed the best effect,and a high dose(1％)did not pose a toxicity risk.

Chunping Wang;Lijun Shang;Qiuping Guo;Yehui Duan;Mengmeng Han;Fengna Li;Yulong Yin;Shiyan Qiao

State Key Laboratory of Animal Nutrition,Ministry of Agriculture Feed Industry Centre,China Agricultural University,Beijing 100193,China;Beijing Bio-feed Additives Key Laboratory,Beijing 100193,China;Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 100045,China;University of Chinese Academy of Sciences,Beijing 100039,China

动物营养（英文）

[1]Chunping Wang;Lijun Shang;Qiuping Guo;Yehui Duan;Mengmeng Han;Fengna Li;Yulong Yin;Shiyan Qiao-.Effectiveness and safety evaluation of graded levels of N-carbamylglutamate in growing-finishing pigs)[J].动物营养（英文）,2022(03):412-418

carbamylglutamate,carbamylgluta,barrows,1N9C

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