Plasma FGF21 concentrations and spontaneous self-selection of protein suggest that 15% protein in the diet may not be enough for male adult rats

Protein requirement has been determined at 10-15% energy. Under dietary self-selection, rats ingest 25-30% energy as protein and regulate FGF21 (a hormone signaling protein deficiency) to levels lower than those measured with a 15% protein (15P) diet. Our hypothesis is that if a 15P diet was indeed sufficient to ensure protein homeostasis, it is probably a too low protein level to ensure optimal energy homeostasis. Adult male Wistar rats were used in this study. The first objective was to determine the changes in food intake, body composition and plasma FGF21, IGF-1 and PYY concentrations in rats fed 8P, 15P, 30P, 40P or 50P diets. The second was to determine whether the FGF21 levels measured in the rats were related to spontaneous protein intake. Rats were fed a 15P diet and then allowed to choose between a protein diet and a protein-free diet. Food intake and body weight were measured throughout the experiments. Body composition was determined at different experimental stages. Plasma samples were collected to measure FGF21, IGF-1 and PYY concentrations. A 15P diet appears to result in higher growth than that observed with the 30P, 40P and 50P diets. However, the 15P diet probably does not provide optimal progression of body composition owing to a tendency of 15P rats to fix more fat and energy in the body. The variable and higher concentrations of FGF21 in the 15P diet suggest a deficit in protein intake, but this does not appear to be a parameter reflecting the adequacy of protein intake relative to individual protein requirements.

Hepatocyte-Specific Phgdh-Deficient Mice Culminate in Mild Obesity, Insulin Resistance, and Enhanced Vulnerability to Protein Starvation

L-Serine (Ser) is synthesized de novo from 3-phosphoglycerate via the phosphorylated pathway committed by phosphoglycerate dehydrogenase (Phgdh). A previous study reported that feeding a protein-free diet increased the enzymatic activity of Phgdh in the liver and enhanced Ser synthesis in the rat liver. However, the nutritional and physiological functions of Ser synthesis in the liver remain unclear. To clarify the physiological significance of de novo Ser synthesis in the liver, we generated liver hepatocyte-specific Phgdh KO (LKO) mice using an albumin-Cre driver. The LKO mice exhibited a significant gain in body weight compared to Floxed controls at 23 weeks of age and impaired systemic glucose metabolism, which was accompanied by diminished insulin/IGF signaling. Although LKO mice had no apparent defects in steatosis, the molecular signatures of inflammation and stress responses were evident in the liver of LKO mice. Moreover, LKO mice were more vulnerable to protein starvation than the Floxed mice. These observations demonstrate that Phgdh-dependent de novo Ser synthesis in liver hepatocytes contributes to the maintenance of systemic glucose tolerance, suppression of inflammatory response, and resistance to protein starvation.

Apparent and standardised ileal digestibility coefficients of amino acids in wheat, soybean meal and rapeseed meal for broilers

The apparent (AID) and(SID) ileal amino acid digestibilities in wheat, soybean meal, and rapeseed meal were determined with Ross 308 broiler chicken (n = 64) using the slaughter technique with chromium mordanted straw as an indigestible marker. The recovery of endogenous amino acids at the distal ileum was determined with a protein-free diet and it was used to calculate the SID digestibilities of the studied feed ingredients. The mean amino acid AID and SID were higher in soybean meal and wheat than in rapeseed meal (p<0.05). The mean amino acid flow measured from the ileum was the highest in rapeseed meal, intermediate in soybean meal, and the lowest in wheat (p<0.05). The main amino acids in the basal endogenous secretion were aspartic and glutamic acid and the lowest ones present were methionine and histidine (p<0.05). The difference between amino acid AID and SID values varied among ingredients and was higher in wheat than in soybean meal and rapeseed meal (p<0.05).

Blood Sampling From Rat Ileal Mesenteric Vein Revealed a Major Role of Dietary Protein in Meal-Induced GLP-1 Response

The present study was conducted to examine region-dependent glucagon-like peptide-1 (GLP-1) responses to “meal ingestion” under physiological (conscious and unrestrained) conditions using rats with a catheter inserted into either the portal vein (PV) or the ileal mesenteric vein (ILMV). After recovery from the cannulation surgery, blood samples were collected from either PV or ILMV catheter before and after the voluntary ingestion of test diets. After an AIN-93G standard diet ingestion, GLP-1 concentration was higher in ILMV than in PV, and postprandial responses of peptide-YY (PYY) had similar trend, while that of glucose dependent-insulinotropic polypeptide showed an opposite trend to GLP-1/PYY responses. In a separated experiment, a protein-enriched diet containing casein at 25% wt/wt transiently increased GLP-1 concentration only in ILMV; however, a protein-free diet did not increase GLP-1 concentrations in PV or ILMV. These results indicate that postprandial GLP-1 is immediately released from the distal intestine under physiological conditions, and that dietary protein has a critical role in the enhancement of postprandial GLP-1 response.

EFFICACY OF CATFISH (PANGASIUS HYPOPHTHALMUS) OIL TO OVERCOME STUNTING BY REDUCING INFLAMMATORY CONDITION

Objective: This study aimed to evaluate the effect of catfish (Pangasius hypophthalmus) oil on hs-CRP and transthyretin levels of undernourished Wistar rats. Methods: Thirty male Wistar rats were divided into five equal groups. Healthy control (KN) is normal rats that consumed a standard diet only and negative control (K-) is undernourished rats that consumed a protein-free diet only. Undernourished rats that consumed a protein free diet and catfish (Pangasius hypophthalmus) oil at doses 0.020 ml/200 g-body-weight/d, 0.040 ml/200 g-body-weight/d and 0.060 ml/200 g-body-weight/d were classified to P1, P2 and P3 groups, respectively. Hs-CRP is a parameter to evaluate inflammatory condition. Transthyretin and body weight are parameters for measuring nutritional status. Results: Treatment of catfish (Pangasius hypophthalmus) oil on P3 group significantly increases body weight of rats (p<0.05) compare to K-, P1 and P2 groups. There were significant difference of hs-CRP levels in P1, P2 and P3 groups (p<0.05) compare to K-. Hs-CRP levels in P1, P2 and P3 groups compared lower to K-but higher than KN. The mean value of hs-CRP levels in the P3 group (dose 0.060 ml/200 g-body-weight/d) was lower than the other treatment groups. Otherwise, there were no significant difference of TTR levels in P1, P2 and P3 group (p>0.05) compared to K-. Conclusion: The present study showed that catfish (Pangasius hypophthalmus) oil has the potential effect to increase body weight and reduce inflammatory biomarker (hs-CRP) levels but has no effect to increase TTR levels in undernourished Wistar rats.

Effects of anti-nutritional factors on the nutritional potential of three varieties of lablab bean (Lablab purpureus ) in rats

Twenty five Wistar strain rats weighing between 68 to 80g were allotted to five dietary groups. Group I received standard protein diet which served as control, group II received a protein-free diet, which served as a negative control, while rats on III, IV and V were given rawRongai Brown (RB), rawRongaiWhite (RW) and rawHighworthBlack (HB) based diets as the main sources of protein, respectively. The rats were fed 10g experimental diets per day for seven days. a 3-day adaptation period, faecal samples were collected quantitatively for four days, bulked for each rat, weighed, oven-dried at 105 C for 24 hr, milled and stored for analyses. All the rats fed the three varieties of raw lablab beans had significant decrease (p

Evaluation of the biological quality of defatted pequi (Caryocar brasiliense Cambess) seed flour protein supplemented with lysine to rats (Rattus norvegicus)

ABSTRACT Objective In the biome of the Brazilian Cerrado, there are a lot of fruit tree species that stand out for their sensory quality and for presenting potentialities in the market of pulp and almond. Among these species, the pequi deserves attention because it has an almond rich in proteins and that is little explored. The aim of this study was to evaluate the biological quality of defatted pequi seed flour supplemented with lysine. Methods Two designs were done in this study; in the first, the animals were divided into four diet groups: control, protein-free, defatted pequi seed flour and defatted pequi seed flour supplemented with lysine. The protein-free diet was exempt of proteins and the other diets had a protein content of 10% and differed in protein source (casein: control diet or defatted pequi seed flour: test diets). The experiment lasted for 14 days. In the second design, 36 animals were used and followed-up for 28 days. The division of the experimental groups was kept, except for the protein-free diet group, which was excluded. By the end of the test, the animals were anaesthetised and euthanized. Results The results showed that the protein efficiency ratio of the control group was significantly higher than the other groups. For the other indices, the groups that received defatted pequi seed flour did not differ statistically among themselves. Conclusion These findings have shown an effect of supplementation on the protein efficiency ratio when comparing the test diets, however, when compared to the control group, no improvement was found.

Rat Bioassay for Evaluation of Protein Quality of Soy-Fortified Complementary Foods

Compositing complementary flours with legumes of high protein quality such as soy can be effective in abating Protein Energy Malnutrition. Soy-fortified complementary flours were developed using locally available foods from Western Kenya and used to determine the fortification effect on protein nutritional quality, growth, and rehabilitation. Ten isonitrogenous diets containing 10% protein and one containing 20% protein were formulated from six foods; maize, pearl millet, finger millet, sorghum, cassava, and banana at ratios of 70:30 flour and soy with milk powder as control and fed to weanling male albino rats. Another group was fed on a protein free diet. Banana: Soy diet had significantly superior protein nutritional quality while Maize: soy had 70% Protein Digestibility Corrected Amino Acid Score. True Protein Digestibility of the fortified diets lay within the acceptable margin for cereal: bean mixtures. Fortification with soy improved protein quality indices of flours in rats, and by extrapolation could support growth of young children if used as complementary foods.