Safety evaluation of disodium 5'-inosinate, disodium 5'-guanylate and disodium 5'-ribonucleotide

Oral Intake of Inosine 5'-Monophosphate in Mice Promotes the Absorption of Exogenous Fatty Acids and Their Conversion into Triglycerides though Enhancing the Phosphorylation of Adenosine 5'-Monophosphate-Activated Protein Kinase in the Liver, Leading to Lipohyperplasia

Inosine 5'-monophoaphate (IMP) is a food additive that promotes serious lipohyperplasia in the liver of C57/KsJ-db/db (db/db) mice. Thus, IMP taken orally by healthy mice might also damage their health. To date, how IMP affects health after being taken by healthy animals is still unclear. Therefore, we investigated the health of C57BL/6J mice affected by IMP intake. Our data revealed that C57BL/6J mice administered 255 μM IMP daily via oral gavage for 4 months caused hyperlipidemia and an increase in body fat rate. The expressions of acetyl-CoA carboxylase 1 (ACC1) and phosphorylated acetyl-CoA carboxylase 2 (ACC2) in hepatocytes increased though the administration of IMP, promoting the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). The conversion of acetyl-CoA into triglycerides (TGs) was promoted by ACC1. These TGs were transported from the hepatocytes to avoid the development of non-alcoholic fatty liver disease (NAFLD), causing a deficiency of acetyl-CoA in the liver, and then, the increased phosphorylated ACC2 promoted the cytoplasm fatty acids entering the mitochondria and conversion into acetyl-CoA through the fatty acid β-oxidation pathway, causing a deficiency in fatty acids. Therefore, the liver showed enhanced absorption of exogenous fatty acids, which were converted into TGs, causing lipohyperplasia. In conclusion, an excessive IMP intake promotes metabolic dysfunction in adipose tissue.

The effect of purine content on sensory quality of pork

Although high level of purine in foods is considered a risk factor for hyperuricemia and gout, purine-rich foods continue to be popular for their delicious taste. The main objective of this study was to investigate the effects of purine bases on the sensory quality of pork. A total of 406 longissimus thoracis et lumborum samples were collected from a heterogeneous F6 pig population to determine purine composition and its correlation to sensory quality of pork. The contents of total purine and two major uricogenic bases (adenine and hypoxanthine) were negatively correlated with tenderness, juiciness, oiliness and overall liking (r < -0.2, P < 0.05), but they were not significantly correlated with umami. In contrast, guanine content, which accounts for only about 10% of the total purine content, was positively correlated with umami (r = 0.15, P < 0.05), and had no significant relationships with other sensory indicators. These results imply that purine bases with different uricogenic effects also influence different sensory quality indices of pork.

The role of dietary nucleotides in single-stomached animals

The transition from liquid to solid feed during weaning results in morphological, histological and microbial changes in the young animal's intestinal tract and often is associated with diarrhoea. The ban of in-feed antibiotics in pig production in the European Union has led to increasing interest in alternatives to overcome weaning-associated problems. Among others, nucleotides may have the potential to alleviate health impairments due to weaning. Nucleotides are natural components of the non-protein fraction of milk and have important effects on the maintenance of health in young animals. Nucleotides and their related metabolic products play key roles in many biological processes and become essential dietary components when endogenous supply is insufficient for normal function. The present review summarises nucleotide composition of milk from different species, the biology of nucleotides and possible effects of dietary nucleotides on intestinal morphology and function, intestinal microbiota, immune function, nutrient metabolism, hepatic morphology and function as well as growth performance. Special attention is given to data available for pigs, and suggestions are made for inclusion of nucleotides in the diet to benefit piglets' health and reduce the consequences accompanying early weaning.

The role of nucleotides in the immune and gastrointestinal systems: potential clinical applications

Nucleotides are low molecular weight biological molecules key to biochemical processes. Sources include de novo synthesis, recovery via salvage mechanisms, and dietary intakes. Although endogenous production serves as the main nucleotide source, evidence suggests that exogenous sources are essential to immune competence, intestinal development, and recovery. Dietary nucleotides serve a marked role in rapidly proliferating cells where they are necessary for optimal function. Accordingly, dietary nucleotides are deemed conditionally essential in the presence of various physiological stresses, including growth and development, recovery from injury, infection, and certain disease states. Clinical studies that evaluated nutrition formulations of nucleotides in combination with other specific nutrient substances demonstrated improved clinical outcomes in patients characterized as critically ill, injured, immune suppressed, or with chronic gastrointestinal conditions. However, conclusions regarding specific benefits of nucleotides are limited. Scientific substantiation of nucleotide supplementation in infant formula has been reported to improve the maturation and development of the intestinal tract as well as immune function. All medical nutrition products except for one immune-modulating formulation are devoid of nucleotides. In an effort to build on this, the current review presents the data to support potential clinical applications for nucleotides in enteral nutrition that may contribute to improved outcomes in physiologically stressed patients.

Effects of dietary inosinic acid on carcass characteristics, meat quality, and deposition of inosinic acid in broilers

An experiment was conducted to evaluate the effects of dietary inosinic acid (inosine 5'-monophosphate, IMP) on carcass characteristics, meat quality, and deposition of IMP in Arbor Acres broilers. A total of two hundred forty 1-d-old male Arbor Acres broilers were allocated to 4 inosinic acid treatments (0, 0.25, 0.50, and 0.75% dietary IMP supplementation). Birds were slaughtered at 42 d old. Dietary IMP did not significantly affect the carcass characteristics of broilers. No significant difference among treatments was observed in muscle pH within 1 h or at 24 h postmortem (PM), or in the decrease of muscle pH within 24 h PM. Inosinic acid had no marked effect on the color of breast muscle or Hunter L* and a* values of thigh muscle. Hunter b* values in thigh muscle were lower (P < 0.05) in the 0.75% IMP supplementation group than in the control group. Both breast and thigh muscle of birds fed with 0.25% IMP diet resulted in a lower (P < 0.05) shear force value compared with those fed with the other diets. All of the test groups had greater (P < 0.05) deposition of IMP in breast and thigh muscle than that of the control group with the exception of the 0.75% IMP supplementation group for thigh muscle. Greater (P < 0.05) corrected IMP value in breast muscle was detected for the test groups compared with the control group. These results suggest that extraneous IMP addition may contribute to the improvement of growth, meat quality, and deposition of IMP in broilers.

Effect of dietary nucleotides on the fatty acid composition of rat liver microsomes

The present study was designed to evaluate the influence of dietary nucleotides on the lipid composition of liver microsomes in weanling rats. Rats at weaning were fed, one group with a semipurified nucleotide-free diet and three groups with the same diet supplemented with three different levels of each of the nucleotides AMP, GMP, IMP, UMP and CMP, during 4 weeks. Long chain polyunsaturated fatty acids of the n-6 and n-3 series were increased in phospholipids of liver microsomes for rats fed the nucleotide supplemented diets; however, the cholesterol/phospholipid phosphorus ratio was maintained fairly constant. The results obtained suggest that dietary nucleotides modify the polyunsaturated fatty acid metabolism through a lower rat liver delta-9 desaturase activity and through increased activities of delta-5 and delta-4 desaturases.

Flavor potentiators

This review provides extensive presentation and evaluation of data relative to flavor potentiation, including the historical, chemical, organoleptic, metabolic, physiological, and consumptive properties of the commonly available flavor potentiators, which are primarily monosodium glutamate and 5'-nucleotides. In addition, their food occurrences, mode of action, manufacturing procedures, and methods of analyses will be discussed. Also, attention will be given to miscellaneous compounds that possess flavor potentiating properties.

Long-term feeding study on disodium 5-ribonucleotide in dogs

Groups of 4 male and 4 female Beagle dogs were fed for 2 years on diets containing 0 (control), 0.1, 1.0 and 2.0%, respectively, of disodium 5'-ribonucleotide (a 50 : 50 mixture of disodium 5'-inosinate and disodium 5'-guanylate). The mean daily intakes of the 3 test groups ranged during the experiment from 0.04-0.03, 0.48-0.26 and 0.93-0.51 g/kg, respectively. No effects attributable to treatment were found in mortality, food consumption, water consumption, bodyweight gain, ophthalmoscopy, clinical signs, haematology, serum chemistry (other than allantoin levels), organ weights, macroscopic pathology or histology, Small differences were observed between mean values in treatment and control dogs for serum allantoin but there was no indication of any persistent significant difference throughout the 2-year study. In a 6-week preliminary test, dietary levels of up to 10% disodium 5'-ribonucleotide were without detectable adverse effect upon beagle dogs of either sex.

The effect of disodium 5-ribonucleotide on reproductive function over three generations in the rat

Deitary levels of 0.1, 1.0 and 2.0% disodium 5-ribonucleotide were administered to rats of the CD strain over 3 generations, and the growth and reproductive performance were compared with those of a control group. Treatment did not appear to affect parent animals, as assessed by the incidence of mortality, bodyweight change, food consumption, mating performance, Pregnancy rate, Gestation Peroid, and post-mortem findings. Total litter loss, Litter size, Litter and mean pup weights, pup mortality and the incidence of skeletal or other variants in the offspring were unaffected by treatment at any dosage level. Additional organ weight analysis and skeletal staining of 10 males and 10 females from all groups, and the histological examination of 10 male and 10 females of the control and 2.0% level groups of the third generation did not provide any evidence of effects that could be related to treatment.