Whey protein reduces early life weight gain in mice fed a high-fat diet.

An increasing number of studies indicate that dairy products, including whey protein, alleviate several disorders of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in mice fed a high-fat diet hypothesising that the metabolic effects of whey would be associated with changes in the gut microbiota composition. Five-week-old male C57BL/6 mice were fed a high-fat diet ad libitum for 14 weeks with the protein source being either whey or casein. Faeces were collected at week 0, 7, and 13 and the fecal microbiota was analysed by denaturing gradient gel electrophoresis analyses of PCR-derived 16S rRNA gene (V3-region) amplicons. At the end of the study, plasma samples were collected and assayed for glucose, insulin and lipids. Whey significantly reduced body weight gain during the first four weeks of the study compared with casein (P<0.001-0.05). Hereafter weight gain was similar resulting in a 15% lower final body weight in the whey group relative to casein (34.0±1.0 g vs. 40.2±1.3 g, P<0.001). Food intake was unaffected by protein source throughout the study period. Fasting insulin was lower in the whey group (P<0.01) and glucose clearance was improved after an oral glucose challenge (P<0.05). Plasma cholesterol was lowered by whey compared to casein (P<0.001). The composition of the fecal microbiota differed between high- and low-fat groups at 13 weeks (P<0.05) whereas no difference was seen between whey and casein. In conclusion, whey initially reduced weight gain in young C57BL/6 mice fed a high-fat diet compared to casein. Although the effect on weight gain ceased, whey alleviated glucose intolerance, improved insulin sensitivity and reduced plasma cholesterol. These findings could not be explained by changes in food intake or gut microbiota composition. Further studies are needed to clarify the mechanisms behind the metabolic effects of whey

Protein Quality and the Protein to Carbohydrate Ratio within a High Fat Diet Influences Energy Balance and the Gut Microbiota In C57BL/6J Mice

peer-reviewedMacronutrient quality and composition are important determinants of energy balance and the gut microbiota. Here, we investigated how changes to protein quality (casein versus whey protein isolate; WPI) and the protein to carbohydrate (P/C) ratio within a high fat diet (HFD) impacts on these parameters. Mice were fed a low fat diet (10% kJ) or a high fat diet (HFD; 45% kJ) for 21 weeks with either casein (20% kJ, HFD) or WPI at 20%, 30% or 40% kJ. In comparison to casein, WPI at a similar energy content normalised energy intake, increased lean mass and caused a trend towards a reduction in fat mass (P = 0.08), but the protein challenge did not alter oxygen consumption or locomotor activity. WPI reduced HFD-induced plasma leptin and liver triacylglycerol, and partially attenuated the reduction in adipose FASN mRNA in HFD-fed mice. High throughput sequence-based analysis of faecal microbial populations revealed microbiota in the HFD-20% WPI group clustering closely with HFD controls, although WPI specifically increased Lactobacillaceae/Lactobacillus and decreased Clostridiaceae/Clostridium in HFD-fed mice. There was no effect of increasing the P/C ratio on energy intake, but the highest ratio reduced HFD-induced weight gain, fat mass and plasma triacylglycerol, non-esterified fatty acids, glucose and leptin levels, while it increased lean mass and oxygen consumption. Similar effects were observed on adipose mRNA expression, where the highest ratio reduced HFD-associated expression of UCP-2, TNFa and CD68 and increased the diet-associated expression of b3-AR, LPL, IR, IRS-1 and GLUT4. The P/C ratio also impacted on gut microbiota, with populations in the 30/ 40% WPI groups clustering together and away from the 20% WPI group. Taken together, our data show that increasing the P/C ratio has a dramatic effect on energy balance and the composition of gut microbiota, which is distinct from that caused by changes to protein quality.KN is supported by the Teagasc Vision Programme on Obesity, which also funded the work detailed in this manuscript. LM is supported by a Teagasc PhD Walsh Fellowship. HMR is supported by SFI PI (11/PI/1119)

New data and phylogenetic placement of the enigmatic old world lupin: Lupinus mariae-josephi H. Pascual.

International audienceLupinus mariae-josephi H. Pascual is an intriguing lupin species recently discovered in the Mediterranean region. New data from seed coat micromorphology, cytology, and DNA sequences were generated in order to extend our knowledge on this species and to examine its evolutionary relationships within Lupinus. This species shows morphological similarities with the Mediterranean smooth seeded species of sections Micranthi and Lutei. It shares the same chromosome number 2n = 52 with the latter Old World taxa, but also with unifoliolate lupins from Florida. Besides, L. mariae-josephi exhibited a seed coat micromorphology ''intermediate'' between the rough and the smooth seed coat types. Phylogenetic analyses using ITS and ETS nrDNA spacers, and the LEGCYC1A locus supported L. mariae-josephi as a distinct Old World line, placed out of the Scabrispermae, but without clear placement amongst the Mediterranean smooth-seeded lineages. Unexpectedly, LEGCYC1A data revealed phylogenetic affinities between L. mariae-josephi and L. villosus, a unifoliolate North American lupin that might have experienced a reticulated evolutionary process. All together, the data underline the phylogenetic interest of L. mariae-josephi in Lupinus and the need of additional investigations in order to definitely elucidate its enigmatic status. Moreover, as L. mariaejosephi is one of the rare Old World lupins strictly restricted to poor basic soils, it opens new perspectives of ecological and agronomic interests in the wide areas of poor calcareous soils in the Mediterranean region