Nutritional utilization by the rat of diets based on lentil (Lens culinaris) seed meal or its fractions

Lentil ( Lens culinaris Medikus) Diet Affects the Gut Microbiome and Obesity Markers in Rat

Lentil, a moderate-energy high-protein pulse crop, provides significant amounts of essential nutrients for healthy living. The objective of this study was to determine if a lentil-based diet affects food and energy intake, body weight, percent body fat, liver weight, and body plasma triacylglycerols (TGs) as well as the composition of fecal microbiota in rats. A total of 36 Sprague-Dawley rats were treated with either a standard diet, a 3.5% high amylose corn starch diet, or a 70.8% red lentil diet for 6 weeks. By week 6, rats fed the lentil diet had significantly lower mean body weight (443 ± 47 g/rat) than those fed the control (511 ± 51 g/rat) or corn (502 ± 38 g/rat) diets. Further, mean percent body fat and TG concentration were lower, and lean body mass was higher in rats fed the lentil diet than those fed the corn diet. Fecal abundance of Actinobacteria and Bacteriodetes were greater in rats fed the lentil or corn starch diets than those fed the control diet. Fecal abundance of Firmicutes, a bacterial phylum comprising multiple pathogenic species, decreased in rats fed the lentil and high-amylose corn starch diets vs the control diet. The lentil-based diet decreased body weight, percent body fat, and plasma triacylglycerols in rats and suppressed intestinal colonization by pathogens.

Current Knowledge on Genetic Biofortification in Lentil

Micronutrient deficiency in the human body, popularly known as "hidden hunger", causes many health problems. It presently affects >2 billion people worldwide, especially in South Asia and sub-Saharan Africa. Biofortification of food crop varieties is one way to combat the problem of hidden hunger using conventional plant breeding and transgenic methods. Lentils are rich sources of protein, micronutrients, and vitamins including iron, zinc, selenium, folates, and carotenoids. Lentil genetic resources including germplasm and wild species showed genetic variability for these traits. Studies revealed that a single serving of lentils could provide a significant amount of the recommended daily allowance of micronutrients and vitamins for adults. Therefore, lentils have been identified as a food legume for biofortification, which could provide a whole food solution to the global micronutrient malnutrition. The present review discusses the current ongoing efforts toward genetic biofortification in lentils using classical breeding and molecular marker-assisted approaches.

Application and opportunities of pulses in food system: a review

Pulses are highly nutritious seeds of pod-bearing leguminous plants, specifically dry peas, lentils, and chickpeas. US farmers harvest about 2.6 million pounds of pulses every year but 75% of this is being exported internationally because of its increased consumption in the developing countries. In the current scenario, increasing costs of production, bad economy, and fluctuating food commodity prices have made a strong case for US producers to seek opportunities to increase domestic consumption of pulses through value-added products. Pulses are the richest sources of plant proteins and provide approximately 10% of the total dietary requirements of the proteins world over. Pulses are also high in dietary fibers and complex carbohydrates leading to low GI (glycemic index) foods. Pulses help to lower cholesterol and triglycerides as leguminous fibers are hypoglycosuria because of consisting more amylose than amylopectin. Pulses provide tremendous opportunities to be utilized in the processed foods such as bakery products, bread, pasta, snack foods, soups, cereal bar filing, tortillas, meat, etc. These show excellent opportunities in frozen dough foods either as added flour or as fillings. Pulses in view of their nutrient profile, seem to be ideal for inclusion in designing snack foods, baby, and sports foods.

Effects of Lens culinaris agglutinin on gene expression of gluconeogenic enzymes in the mouse intestine

BACKGROUND

Lectins are proteins that bind specifically to the carbohydrate moiety of glyco-conjugates. Japanese mistletoe lectin given intragastrically affected cytokine gene expression in the mouse intestine. This study examines the actions of Lens culinaris agglutinin (LCA) on the gene expression of gluconeogenic enzymes in the intestine.

RESULTS

The results of quantitative real-time reverse transcription-polymerase chain reaction indicated that LCA caused an up-regulation of the gene expression of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK). This change was correlated with an increase in the expression of two transcription factors, HNF1α and HNF4α. Experiments using human colonic cancer Caco-2 cells demonstrated that LCA up-regulated the gene expression of G6Pase and PEPCK whereas insulin had the opposite effect. In addition, the observed up-regulation of HNF4α gene expression in the duodenum raises the possibility that the lectin promotes the colorectal cancer.

CONCLUSION

Lentil beans should be cooked well to avoid unfavourable effects of LCA.

Purified chickpea or lentil proteins impair VLDL metabolism and lipoprotein lipase activity in epididymal fat, but not in muscle, compared to casein, in growing rats

BACKGROUND

It is well known that the legume proteins have a lowering effect on plasma cholesterol and triacylglycerols (TG) concentrations compared to animal proteins. The protein itself, as well as non-protein constituents, naturally present in legumes may be implicated.

AIM OF THE STUDY

The effects of various dietary purified legumes proteins compared to casein, were determined on plasma TG level, VLDL concentration and composition. Moreover, lipoprotein lipase (LPL) activity in epididymal fat, gastrocnemius and heart was investigated to evaluate in these tissues their capacity to release free fatty acids from their TG substrate and the liver capacity to stock the TG.

METHODS

Weaning male Wistar rats were fed ad libitum one of the following diets: 200 g/kg diet of purified proteins of lentil (L), or chickpea (CP) or casein (CAS). At day 28, VLDL were isolated from plasma sample by a single ultracentrifugation flotation. Hepatic lipase and LPL activity in epididymal fat, gastrocnemius and heart were measured by using glycerol tri [9-10(n)-(3)H] oleate emulsion as substrate.

RESULTS

Compared with CAS diet, the CP and L protein diets exhibited similar cholesterolemia, but lower triglyceridemia (1.9-fold and 2.5-fold) and VLDL particle number, as measured by their reduced contents of TG and apolipoproteins. CP and L protein diets reduced liver TG and cholesterol by 31 and 45%, respectively compared to CAS diet. Furthermore, LPL activity in adipose tissue of rats fed CP or L was 1.6-fold lower than that of rats fed CAS. There was no significant difference in heart and gastrocnemius LPL activities with the three proteins. In contrast, hepatic lipase activity was higher in rats fed CP and L diets.

CONCLUSION

The low food efficiency ratio of purified CP and L proteins related to CAS is associated with decreased plasma VLDL and adipose tissue LPL activity. The low liver TG concomitant with reduced TG and apolipoproteins contents of VLDL confirm that hypotriglyceridemia is essentially due to impaired synthesis, exportation and transport of TG by VLDL which prevent lipid storage in adipose tissue.

Differential Effects of Cooked Beans and Cooked Lentils on Protein Metabolism in Intestine and Muscle in Growing Rats

AIMS

The effect of diets based on cooked beans or lentils on protein metabolism in intestines and muscles was studied in rats.

METHOD

The cooked seeds were used as the unique protein source in balanced diets (containing 229 and 190 g of crude protein per kg dry matter) fed to young growing rats for 20 days. Their effects were compared with those of the control casein diet in pair-fed rats. Protein synthesis rates in small and large intestines and in gastrocnemius and soleus muscles were determined in vivo, in a fed state, by the flooding dose method, using 13C-valine.

RESULTS

In the small and large intestine tissues of the legume fed groups, protein, RNA relative masses (mg.100 g BM(-1)) and protein synthesis rates (FSR and ASR) were higher than in the control rats (p < 0.05). In gastrocnemius and soleus muscles,protein and RNA contents (in mg) and protein synthesis rates were significantly (p < 0.05) lower in the legume-fed groups than in the control rats.

CONCLUSION

The chronic intake of cooked legumes increased protein synthesis rates in intestinal tissues and decreased them in muscles. This effect was greater for beans than for lentils in the large intestine and in gastrocnemius muscle.

Antinutritional properties of plant lectins

Lectins are carbohydrate binding (glyco)proteins which are ubiquitous in nature. In plants, they are distributed in various families and hence ingested daily in appreciable amounts by both humans and animals. One of the most nutritionally important features of plant lectins is their ability to survive digestion by the gastrointestinal tract of consumers. This allows the lectins to bind to membrane glycosyl groups of the cells lining the digestive tract. As a result of this interaction a series of harmful local and systemic reactions are triggered placing this class of molecules as antinutritive and/or toxic substances. Locally, they can affect the turnover and loss of gut epithelial cells, damage the luminal membranes of the epithelium, interfere with nutrient digestion and absorption, stimulate shifts in the bacterial flora and modulate the immune state of the digestive tract. Systemically, they can disrupt lipid, carbohydrate and protein metabolism, promote enlargement and/or atrophy of key internal organs and tissues and alter the hormonal and immunological status. At high intakes, lectins can seriously threaten the growth and health of consuming animals. They are also detrimental to numerous insect pests of crop plants although less is presently known about their insecticidal mechanisms of action. This current review surveys the recent knowledge on the antinutritional/toxic effects of plant lectins on higher animals and insects.

Differential Effects of Cooked Common Bean (Phaseolus vulgaris) and Lentil (Lens esculenta puyensis) Feeding on Protein and Nucleic Acid Contents in Intestines, Liver and Muscles in Rats

AIM

Our aim was to investigate the influence of legume feeding on the protein and nucleic acid content of intestinal tissues and muscles.

METHODS

Growing male Wistar rats were fed ad libitum on balanced diets containing cooked common bean or lentil as the unique protein source (180 g.kg(-1) dry matter) for 20 days. The control group was pair-fed with an iso-energetic, iso-nitrogenous balanced casein diet.

RESULTS

Intestinal tissues were heavier in the legume-fed groups and higher relative mass (g per 100 g body mass) of protein, RNA and DNA were found in these tissues as compared to those of the control groups. In liver protein and RNA masses were significantly lower in the bean group than in the control group but the DNA content was not different in the legume and in the control groups. In gastrocnemius and soleus muscles, there was no significant effect of legume feeding on the fresh mass and on the protein and RNA contents, but the DNA content of the m. gastrocnemius was significantly lower in both legume groups than in their control group. The ribosomal capacity of intestines, liver and muscles was not significantly affected by legume feeding.

CONCLUSION

Legume feeding had a trophic effect on both proximal and distal intestinal tissues; dietary fiber appears to be the main cause of this effect.