Altered lipid metabolism in rat offspring of dams fed a low-protein diet containing soy protein isolate

Effects of maternal branched-chain amino acid and alanine supplementation on growth and biomarkers of protein metabolism in dams fed a low-protein diet and their offspring

A considerable number of studies have reported that maternal protein restriction may disturb fetal growth and organ development due to a lower availability of amino acids. Leucine, one of branched-chain amino acid (BCAA) promotes protein synthesis through mechanistic target of rapamycin signaling. Here, we investigated the effects of BCAA supplementation in the dams fed a low-protein diet on serum and hepatic biochemical parameters of protein metabolism of dams and their offspring. Female ICR mice were fed a control (20% casein), a low-protein (10% casein), a low-protein with 2% BCAAs or a low-protein with 2% alanine diet for 2 weeks before mating and then throughout pregnancy and lactation. Alanine was used as an amino nitrogen control for the BCAA. Dams and their male offspring were sacrificed at postnatal day 21. There were no changes in body weight and fat mass in low-protein fed dams; however, BCAA supplementation significantly increased fat mass and serum leptin levels. Low-protein diet consumption reduced maternal protein synthesis based on biochemical analysis of serum albumin and hepatic protein levels and immunoblotting of S6 protein, which were increased by BCAA and alanine supplementation. Offspring from dams fed a low-protein diet exhibited lower body and organ weights. Body weight and hepatic protein levels of the offspring were increased by alanine supplementation. However, the decreased serum biochemical parameters, including glucose, triglyceride, total protein and albumin levels in the low-protein offspring group were not changed in response to BCAA or alanine supplementation. A reduced density of the hepatic vessel system in the offspring from dams fed a low-protein diet was restored in the offspring from dams fed either BCAA and alanine-supplemented diet. These results suggest that supplementation of amino nitrogen per se may be responsible for inducing hepatic protein synthesis in the dams fed a low-protein diet and alleviating the distorted growth and liver development of their offspring.

Maternal soy protein isolate diet during lactation programs deleterious effects on hepatic lipid metabolism, atherogenic indices, and function of adrenal in adult rat offspring

The benefits of consuming soy and its protein have been reported in many studies. However, its phytoestrogen content raises concerns about consumption during lactation and gestation We therefore examined the effects of soybean or soy protein isolate on the parameters-related cardiovascular pathophysiology in lactating mothers and their offsprings at weaning and adulthood. Lactating rats were divided: casein control (C); soy protein isolate (SPI); and soybean (S). At weaning, half of the litter received commercial ration up to 150 days. The levels of 17-β-estradiol and superoxide dismutase were low in the S mothers. For the SPI mothers, we observed a reduction of thiobarbituric acid reactive substances (TBARS). At weaning, atherogenic indices [1 = total cholesterol (TC)/HDL; 2 = LDL/HDL; 3 = TC-HDL/HDL)] decreased in the S and SPI offsprings compared to the casein control group; TBARS and antioxidant enzymes increased in the S offspring, while reduced/oxidized glutathione ratio increased in the SPI offspring, indicating lower oxidative stress. In adulthood, the SPI offspring showed an increase in liver cholesterol and atherogenic index 1 and 3 (vs. C and S) and 2 (vs. S). In addition, we found a decrease in catecholamines in the adrenal medulla and an increase in caffeine-stimulated secretion, but tyrosine hydroxylase expression remained constant. Maternal consumption of SPI during lactation worsened atherogenic indices of the offsprings in adulthood, which was associated with increased liver cholesterol and decreased catecholamines in the adrenal medulla. Soy consumption had no consistent long-term effects on the evaluated parameters compared to casein consumption. The data suggest that the consumption of SPI during lactation should be done with caution.

Of Mice and Men: The Effect of Maternal Protein Restriction on Offspring's Kidney Health. Are Studies on Rodents Applicable to Chronic Kidney Disease Patients? A Narrative Review

In the almost 30 years that have passed since the postulation of the "Developmental Origins of Health and Disease" theory, it has been clearly demonstrated that a mother's dietary habits during pregnancy have potential consequences for her offspring that go far beyond in utero development. Protein malnutrition during pregnancy, for instance, can cause severe alterations ranging from intrauterine growth retardation to organ damage and increased susceptibility to hypertension, diabetes mellitus, cardiovascular diseases and chronic kidney disease (CKD) later in life both in experimental animals and humans. Conversely, a balanced mild protein restriction in patients affected by CKD has been shown to mitigate the biochemical derangements associated with kidney disease and even slow its progression. The first reports on the management of pregnant CKD women with a moderately protein-restricted plant-based diet appeared in the literature a few years ago. Today, this approach is still being debated, as is the optimal source of protein during gestation in CKD. The aim of this report is to critically review the available literature on the topic, focusing on the similarities and differences between animal and clinical studies.

Effects of Long-Term Protein Restriction on Meat Quality, Muscle Amino Acids, and Amino Acid Transporters in Pigs

This study aimed to investigate the long-term effects of protein restriction from piglets to finishing pigs for 16 weeks on meat quality, muscle amino acids, and amino acid transporters. Thirty-nine piglets were randomly divided into three groups: a control (20-18-16% crude protein, CP) and two protein restricted groups (17-15-13% CP and 14-12-10% CP). The results showed that severe protein restriction (14-12-10% CP) inhibited feed intake and body weight, while moderate protein restriction (17-15-13% CP) had little effect on growth performance in pigs. Meat quality (i.e., pH, color traits, marbling, water-holding capacity, and shearing force) were tested, and the results exhibited that 14-12-10% CP treatment markedly improved muscle marbling score and increased yellowness (b*). pH value (45 min) was significantly higher in 17-15-13% CP group than that in other groups. In addition, protein restriction reduced muscle histone, arginine, valine, and isoleucine abundances and enhanced glycine and lysine concentrations compared with the control group, while the RT-PCR results showed that protein restriction downregulated amino acids transporters. Mechanistic target of rapamycin (mTOR) signaling pathway was inactivated in the moderate protein restricted group (17-15-13% CP), while severe protein restriction with dietary 14-12-10% CP markedly enhanced mTOR phosphorylation. In conclusion, long-term protein restriction affected meat quality and muscle amino acid metabolism in pigs, which might be associated with mTOR signaling pathway.

Different Effects of Maternal Low-Isoflavone Soy Protein and Genistein Consumption on Hepatic Lipid Metabolism of 21-Day-Old Male Rat Offspring

Amino acid composition and isoflavone are alleged contributors to the beneficial effects of soy protein isolate (SPI) on lipid metabolism. Therefore, we investigated the contributing component(s) of SPI in a maternal diet to the regulation of lipid metabolism in offspring. We also determined serum parameters in dams to investigate specific maternal cues that might be responsible for this regulation. Female rats were fed either a casein (CAS), a low-isoflavone SPI, or a casein plus genistein (GEN, 250 mg/kg) diet for two weeks before mating, as well as during pregnancy and lactation. Male offspring (CAS, SPI and GEN groups) were studied 21 days after birth. The SPI group had lower serum triglyceride levels than the other groups. Serum cholesterol was reduced in both the SPI and GEN groups compared with the CAS group. Expressions of target genes of peroxisome proliferator-activated receptor α were altered in the SPI group. Serum aromatic amino acid levels in dams were associated with serum triglyceride in offspring. In conclusion, the maternal consumption of a low-isoflavone SPI diet or a casein diet containing genistein has different effects on the lipid metabolism of their offspring; however, more profound effects were observed in the SPI group. Therefore, the altered lipid metabolism of offspring may be attributed to amino acid composition in maternal dietary protein sources.