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N-carbamylglutamate (NCG) improving reproductive performance, growth performance, and the regulatory effect on meat quality has been proven in finishing pigs. However, little research has investigated the use of NCG in growing-finishing pigs, and safety evaluation and optimal supplementation dose. The aim of this study was to investigate the effects of graded levels of NCG on performance, blood biochemical indexes, carcass traits, and related indicators in growing-finishing pigs, and determine the optimal supplemental level.
Methods: One hundred and forty-four growing-finishing pigs (Duroc × Large White × Landrace, 32.24 ± 1.03 kg) were used in a 74-day 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. 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. Blood samples, muscle quality measurements, and total fatty acid and gene expression in the longissimus dorsi muscle were analysed.
Results: Compared with the control group, the final body weight and average daily gain tended to be higher in the 0.1% group, the lean percentage tended to be higher in the 0.05% group, the levels of free amino acids in the blood increased in the 0.1% group, both 0.1% and 0.15% NCG supplementation increased the levels of nitric oxide in serum and muscle growth- and lipid metabolism-related gene expression and NCG supplementation improved C18:1N9C monounsaturated fatty acids in a dose-dependent manner. In addition, routine blood tests, blood biochemical indexes, and histopathological examination revealed no abnormalities.
Conclusion: It is concluded that increasing the levels of N-carbamylglutamate did not linearly improve growth performance and fatty acid metabolism; the 0.1% dose showed the best effect, and a high dose (1%) did not show a toxicity risk.
Wang, C., Shang, L., Guo, Q., Duan, Y., Han, M., Li, F., Yin, Y., & Qiao, S. (2022). Effectiveness and safety evaluation of graded levels of N-carbamylglutamate in growing-finishing pigs. Animal Nutrition, 10, 412-418. https://doi.org/10.1016/j.aninu.2022.04.012