Effectiveness of citrulline and N-carbamoyl glutamate as arginine precursors on reproductive performance in mammals: A systematic review

Abstract

The use of functional nutrients has been proposed to reduce the occurrence of intrauterine growth retardation in animals at birth in several mammalian species. The objective of this study was to verify the effectiveness of citrulline and N-carbamylglutamate (NCG) dietary supplementation as arginine precursors for mammalian species, and the effects on fetal development through a systematic review. The search for studies was performed during August 2018 in the PubMed, ISI Web of Science, Science Direct, and Scopus databases. The literature search was conducted using “arginine precursor”, “citrulline”, or “N-carbamylglutamate” as keywords, combined with “gestation”, “pregnancy”, “fetus”, “newborn”, or “reproduction”. Studies in which arginine precursors were evaluated in gestating mammals and their effects on parameters related to the intrauterine development of the conceptus were selected. Of 1,379 articles, 18 were selected, primarily based on the title and the abstract. Supplementation with NCG (0.5 g to 2 g/kg of feed) increased maternal plasma arginine concentrations in all studies that evaluated this variable. Fetal number increased in 55.56% of the studies that evaluated it, and fetal weight increased in the majority (62.5%) of the studies evaluating this variable. By supplementing citrulline, only fetal weight was improved, with an increase in maternal plasma arginine in 40% of the studies. In conclusion, N-carbamoyl glutamate seems to be an arginine precursor more effective than L-citrulline during gestation; however, both precursors, beside L-Arginine, should be evaluated in similar conditions to confirm the existence of specific particularities such as periods and levels of supplementation, which need to be considered for different species of animals. The supplementation of NCG increases arginine concentrations in maternal plasma, thus improving mammalian reproductive efficiency and fetal development, mainly by promoting higher birth weight.

Effects of dietary N-carbamylglutamate supplementation on milk production performance, nutrient digestibility and blood metabolomics of lactating Holstein cows under heat stress

“…However, with the high arginase activity or rumen degradation, arginine is rapidly degraded with short biological half-time. Furthermore, the high dietary level of arginine may cause an absorption disorder of lysine due to the competition for the common transporters [3]. Moreover, arginine is uneconomically used in cows for its high cost.…”

“…3 : triiodothyronine, T 4 : thyroxine, GH: growth hormone, PRL: prolactin, SOD: superoxide dismutase, HSP-70: heat shock protein-70. In the same row, different small letter superscripts mean P < 0.05.…”

Meat Quality and Fatty Acid Profiles of Chinese Ningxiang Pigs Following Supplementation with N-Carbamylglutamate

“…Indeed, the use of nutritional approaches to optimize meat fatty acid composition has been a popular research topic, for example, supplying specific additives in diets such as linseeds, plant extracts [4,5]. The application of N-carbamylglutamate (NCG) as a dietary supplement for the health of humans and animals also has gained increasing interest [6][7][8].…”

Dietary Supplementation of L-Arginine and N-Carbamylglutamate Attenuated the Hepatic Inflammatory Response and Apoptosis in Suckling Lambs with Intrauterine Growth Retardation

“…Maternal nutrition of L-arginine (L-Arg), a semiessential amino acid, and its precursor N-carbamylglutamate (NCG) during pregnancy has been shown to mitigate the IUGRmetabolic disruptions in ovine fetus [18][19][20][21] and rat offspring [22] and enhance fetal development and neonatal survival and growth in mammals [23][24][25]. Also, L-Arg and NCG have been shown to protect the liver against lipid peroxidation [26][27][28] as well as play a key role in inflammatory response regulation [29].…”