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

Jorge Y. P. Palencia,Marcio G. Zangeronimo,Allan P. Schinckel,Márvio Lobão Teixeira Abreu,Alysson Saraiva,Cesar Augusto Pospissil Garbossa,Jaap A. Joles

doi:10.1371/journal.pone.0209569

Jorge Y. P. Palencia, Marcio G. Zangeronimo + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0209569

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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.

Highlights

Lower fetal numbers and reduced fetal growth are the result of an imbalance between the placenta’s ability to deliver oxygen and/or nutrients and fetal demand [1]
Most of the articles selected for the present study were initially found in the first used database, Pubmed
Even with a large number of results, no new articles that fit the selection criteria were added from the databases Science Direct and Scopus

Summary

Introduction

Lower fetal numbers and reduced fetal growth are the result of an imbalance between the placenta’s ability to deliver oxygen and/or nutrients and fetal demand [1] It is a major problem associated with livestock production because of increased rates of perinatal morbidity and mortality, increased incidence of disease, reduced productive performance, reduced carcass and meat quality, and even reduced performance in animal athletes [2; 3]. Gestational nutrition affects the health and development of the progeny through the epigenetic pathway by altering mRNA expression for genes involved in morphological, organogenic, and adaptive physiological responses. This phenomenon is known as “fetal programming through nutrition” [4]. This process contributes to implantation, embryogenesis, uterine quiescence during gestation, growth, development, and fetal survival [6; 7; 8]

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