Comparison of the effect of Saccharomyces cerevisiae-Megasphaera elsdenii and buffer on growth performance, digestibility, ruminal histomorphometry, and carcass characteristics of fattening lambs in high concentrate diet.

This study aimed to investigate the effect of rumen pH-adjusting additives in the high-concentrated diet on functional traits, nutrient digestion, some meat parameters, and histomorphometry, and rumen histopathology. Twenty-four Arabia male lambs with 3 to 4 months old and initial body weight of 23.9 ± 3.15 kg were used in a completely randomized design with three treatments and eight replicates. The study was 77 days, including 14 days of the adaptation period and 63 days of the record taking and sampling period. The experimental treatments consisted of a control diet, control diet + sodium bicarbonate buffer, control diet + Megasphaera elsdenii, and Saccharomyces cerevisiae (bacterial-yeast). Rumen fluid was taken by stomach tube at 3 h after morning feeding to measure pH. The lambs were weighed every 3 weeks during the period, and the body weight changes, average daily gain, and total weight gain were measured, and the feed conversion ratio was calculated. At the end of the experiment, the lambs were slaughtered, and the longissimus dorsi muscle was prepared to determine the meat parameters. For histological studies, the abdominal rumen sac was sampled. There were no differences among treatments in dry matter intake (DMI), daily weight gain (ADG), and feed conversion ratio (P > 0.05). Propionate concentration was higher in the bacteria-yeast treatment than other treatments (P < 0.05). Protein digestibility was higher in control and bacteria-yeast treatments than buffer treatment (P < 0.05). The percentage of meat protein, carcass weight, and dressing percentage in bacterial-yeast treatment was higher than other treatments (P < 0.05). Rumen wall thickness in the buffer and bacterial-yeast receiving treatments was greater than the control treatment and was significant in the buffer treatment compared to the control treatment (P < 0.05). The thickness of rumen epithelial tissue in the buffer and bacterial-yeast recipient treatments was less than the control treatment (P < 0.05). Rumen papillae thickness was higher in the control treatment than other treatments (P < 0.05). Hydropic degeneration and parakeratosis were less in pH-regulating treatments than in control. The results showed that the use of Megasphaera elsdenii could be an effective way to modulate the ruminal fermentation conditions of lambs fed with high concentrate diets. In addition, to increaseing dressing percentage and meat protein, it can also reduce tissue damage and improve ruminal tissue structure.

Daily mycoprotein consumption for 1 week does not affect insulin sensitivity or glycaemic control but modulates the plasma lipidome in healthy adults: a randomised controlled trial.

Mycoprotein consumption has been shown to improve acute postprandial glycaemic control and decrease circulating cholesterol concentrations. We investigated the impact of incorporating mycoprotein into the diet on insulin sensitivity (IS), glycaemic control and plasma lipoprotein composition. Twenty healthy adults participated in a randomised, parallel-group trial in which they consumed a 7 d fully controlled diet where lunch and dinner contained either meat/fish (control group, CON) or mycoprotein (MYC) as the primary source of dietary protein. Oral glucose tolerance tests were performed pre- and post-intervention, and 24 h continuous blood glucose monitoring was applied throughout. Fasting plasma samples were obtained pre- and post-intervention and were analysed using quantitative, targeted NMR-based metabonomics. There were no changes within or between groups in blood glucose or serum insulin responses, nor in IS or 24 h glycaemic profiles. No differences between groups were found for 171 of the 224 metabonomic targets. Forty-five lipid concentrations of different lipoprotein fractions (VLDL, LDL, intermediate-density lipoprotein and HDL) remained unchanged in CON but showed a coordinated decrease (7-27 %; all P < 0·05) in MYC. Total plasma cholesterol, free cholesterol, LDL-cholesterol, HDL2-cholesterol, DHA and n-3 fatty acids decreased to a larger degree in MYC (14-19 %) compared with CON (3-11 %; P < 0·05). Substituting meat/fish for mycoprotein twice daily for 1 week did not modulate whole-body IS or glycaemic control but resulted in changes to plasma lipid composition, the latter primarily consisting of a coordinated reduction in circulating cholesterol-containing lipoproteins.

Long-Term Intake of Pork Meat Proteins Altered the Composition of Gut Microbiota and Host-Derived Proteins in the Gut Contents of Mice.

SCOPE: This study is to investigate the effects of long-term intake of pork protein on the composition of gut microbiota and proteins in mice. METHODS AND RESULTS: C57BL/6J mice are fed pork meat protein diets for 240 days, and the composition of gut microbiota and proteins in luminal contents from the duodenum to the colon are analyzed by 16S rRNA gene sequencing and LC-MS/MS. The stewed pork protein diet group has a highly similar microbiota composition to that of the cooked pork protein diet group, but different from the pork emulsion sausage or dry-cured pork protein diet groups. Lachnospiraceae NK4A136, Odoribacter, Defluviitaleaceae UCG-011, Ruminiclostridium 9, Blautia, Lachnoclostridium, and Ruminococcaceae UCG-010 play an important role in response to changes in gut luminal proteins. Specific microbes are significantly correlated with the Cela3b and Cpa1 that are derived from the host and involve protein digestion and absorption. CONCLUSIONS: Pork meat protein diets alter the gut microbiota composition and specific gut microbes may have a great impact on protein digestion and absorption by regulating the secretion of digestive proteins from the host. These findings provide a new insight into the associations of long-term intake of meat protein diet with gut microbiota and host.

Pork Meat Proteins Alter Gut Microbiota and Lipid Metabolism Genes in the Colon of Adaptive Immune-Deficient Mice.

SCOPE: Excessive consumption of processed meat has been linked to an increasing risk of gut diseases. It is investigated how pork meat proteins affect colon homeostasis between normal and immune-compromised mice. METHODS AND RESULTS: Immune-deficient mice (Rag1-/- ) and wild-type mice are fed a diet that contains 20% casein or protein isolated from cooked pork or dry-cured pork for 3 months. Rag1-/- mice show greater variations in transcriptome responses and higher microbial diversity than wild-type mice after consumption of the pork meat protein diets. Intake of pork meat protein diets also increases body weight and induces colonic oxidative stress, low-grade inflammation, and gene expression involved in immune function, cell cycle, and migration. Key genes like Hmox1, Ppara, and Pparg are highly upregulated by pork meat protein. These changes are associated with decreased abundances of Blautia, Bifidobacterium, and Alistipes and increased abundances of Akkermansia muciniphila and Ruminococcaceae. CONCLUSION: Pork meat proteins affect colon health in both wild-type and Rag1-/- mice by altering the microbiome profile under the complex interaction with adaptive immunity. The findings herein give a new insight into the understanding of meat intake, immunity, and gut health.

Meat Proteins as Dipeptidyl Peptidase IV Inhibitors and Glucose Uptake Stimulating Peptides for the Management of a Type 2 Diabetes Mellitus In Silico Study.

Diabetes mellitus is a non-communicable disease entity currently constituting one of the most significant health problems. The development of effective therapeutic strategies for the prevention and/or treatment of diabetes mellitus based on the selection of methods to restore and maintain blood glucose homeostasis is still in progress. Among the different courses of action, inhibition of dipeptidyl peptidase IV (DPP-IV) can improve blood glucose control in diabetic patients. Pharmacological therapy offering synthetic drugs is commonly used. In addition to medication, dietary intervention may be effective in combating metabolic disturbances caused by diabetes mellitus. Food proteins as a source of biologically active sequences are a potential source of anti-diabetic peptides (DPP-IV inhibitors and glucose uptake stimulating peptides). This study showed that in silico pork meat proteins digested with gastrointestinal enzymes are a potential source of bioactive peptides with a high potential to control blood glucose levels in patients with type 2 diabetes mellitus. Analysis revealed that the sequences released during in silico digestion were small dipeptides (with an average weight of 270.07 g mol-1), and most were poorly soluble in water. The selected electron properties of the peptides with the highest bioactivity index (i.e., GF, MW, MF, PF, PW) were described using the DFT method. The contribution of hydrophobic amino acids, in particular Phe and Trp, in forming the anti-diabetic properties of peptides released from pork meat was emphasized.

Meat proteins in a high-fat diet have a substantial impact on intestinal barriers through mucus layer and tight junction protein suppression in C57BL/6J mice.

Protein diets are well known for body maintenance and weight loss. However, it remains unclear whether and how different protein sources affect the intestinal epithelial integrity through tight junctions, mucus secretions and host immunity in diet-induced obesity. To evaluate possible effects, soybean, chicken and pork proteins either with low fat (12% kcal) or high fat (60% kcal) were administered to C57BL/6J mice for 12 weeks. Muc2 expression, tight junction proteins, goblet cells, and inflammatory cytokines in the colon and serum were measured. The intake of a high-fat pork protein diet decreased the number of goblet cells and inhibited Muc2 expression in the colon, which impaired the mucus barrier. Immunohistochemistry indicated decreased crypt depth and downregulation of tight junction proteins in high-fat diet fed mice, signifying losses of epithelial barriers. In addition, a pork protein diet reduces the key zonula occludens-1 and E-cadherin proteins. A high-fat meat protein diet induces colonic inflammatory injury by upregulating several key cytokines and increasing IL-1ß, TNF-α, IL-6 and IFN-γ concentrations in serum. The intake of high-fat meat protein diets resulted in the impairment of the colon barrier through mucus suppression, downregulation of tight junctions, and gut inflammation in mice.

Glycated Beef Protein Hydrolysates as Sources of Bitter Taste Modifiers.

Being averse to bitter taste is a common phenomenon for humans and other animals, which requires the pharmaceutical and food industries to source compounds that can block bitterness intensity and increase consumer acceptability. In this work, beef protein alcalase hydrolysates (BPAH) and chymotrypsin hydrolysates (BPCH) were reacted with glucose to initiate Maillard reactions that led to the formation of glycated or advanced glycation end products (AGEs), BPAH-AGEs and BPCH-AGEs, respectively. The degree of glycation was higher for the BPAH-AGEs (47-55%) than the BPCH-AGEs (30-38%). Analysis by an electronic tongue instrument showed that BPAH-AGEs and BPCH-AGEs had bitterness scores that were significantly (p < 0.05) less than quinine. The addition of BPAH-AGEs or BPCH-AGEs to quinine led to significant (p < 0.05) reductions (up to 38%) in bitterness intensity of quinine. The use of 3% hydrolysate to react with glucose yielded glycated peptides with a stronger ability to reduce quinine bitterness than when 1% was used. Calcium release from HEK293T cells stably expressing the T2R4 human bitter taste receptor was significantly (p < 0.05) attenuated by BPAH-AGEs (up to 96%) and BPCH-AGEs (up to 92%) when compared to the BPAH (62%) and BPCH (3%) or quinine (0%). We concluded that BPAH-AGEs and BPCH-AGEs may be used as bitter taste blockers to formulate better tasting foods.

Different duck products protein on rat physiology and gut microbiota.

We report the effects of protein from different duck products on the intestinal flora and physiology of rats. After 30 days of feeding, rats fed water-boiled salted duck protein had the lowest gut microbial diversity and richness. Allobaculum, Lactobacillus, Coprococcus and Eubacterium increased in rats fed wine-cured duck protein, while rats fed water-boiled salted and wine-cured duck protein showed increased serum urea (UREA) concentrations and serum cholesterol (CHOL) to HDL-cholesterol (HDLC) ratios, but decreased retroperitoneal white adipose tissue (rWAT) and perirenal white adipose tissue (pWAT) to body weight ratios. The changes in gut bacteria were mainly associated with the fat-mass index (weight of rWAT or pWAT to body weight ratio), accompanied by the opposite correlation with UREA content. SIGNIFICANCE: It showed that protein from different duck products impacted the intestinal flora and caused physiological changes in rats. Different sources of processed protein vary in their digestibility and digestive kinetics, all of which can affect the intestinal microbiota and physiology. We report the effects is an effort to map the complex interactions of "host physiology-nutrition-microbiota" in order to provide some insights into that food processing can be improved to promote beneficial gut microbes and enhance human health.