Microbial colonization dynamics of the postnatal digestive tract of Bos indicus calves.

The rumen and the jejunum of calves have distinct functional roles; the former is in the storage and fermentation of feed, and the latter is in transporting digesta to the ileum. It is unknown how nutrition changes the evolution of the microbiome of these organs after birth. We sequenced and characterized the entire microbiome of the rumen and the jejunum from Bos indicus calves of the Mexican Tropics to study their dynamics at Days 0, 7, 28, and 42 after birth. Operational taxonomic units (OTUs) belonging to 185 and 222 genera from 15 phylum were observed in the organs, respectively. The most abundant OTUs were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. We observed that proteobacterial species were outcompeted after the first week of life by Bacteroidetes and Firmicutes in the rumen and the jejunum, respectively. Moreover, Prevotella species were found to predominate in the rumen (36% of total OTUs), while the jejunum microbiome is composed of small proportions of several genera. Presumably, their high relative abundance assists in specialized functions and is more likely in fermentation since they are anaerobes. In summary, the rumen and the jejunum microbiomes were outcompeted by new microbiomes in a dynamic process that begins at birth.

Chia seeds and chemical-elicited sprouts supplementation ameliorates insulin resistance, dyslipidemia, and hepatic steatosis in obese rats.

Chia seeds (CS) and sprouts are rich in bioactive compounds. This study aimed to assess the effects of germination and chemical elicitation (salicylic acid [SA]; hydrogen peroxide [H2 O2 ]) on proximate chemical, total phenolics compounds (TPC), non-extractable proanthocyanidins (NEPA), and carotenoids content of chia sprouts; besides, the effects of their supplementation on obesity-associated complications in rats fed with high-fat and fructose diet (HFFD) were evaluated. Protein, carbohydrate, TPC, NEPA, and carotenoids content were higher in sprouts than CS; elicitation enhanced TPC and carotenoids compared to non-elicited (NE) sprouts. CS, NE, and elicited chia sprouts ameliorated insulin resistance and dyslipidemia at the same level in HFFD-fed rats. NE and SA-chia sprouts exerted the biggest reduction in hepatic triglycerides, which could be partially related to inhibition of pancreatic lipase activity. In addition, SA elicitation induced the greatest effect on insulin levels and corporal weight. CS and their sprouts decreased obesity and its complication, mainly SA-elicited sprouts. PRACTICAL APPLICATIONS: The growing epidemic of non-communicable diseases such as diabetes and obesity has led to the search for prevention and treatment through lifestyle changes, including the consumption of foods rich in bioactive compounds, such as seeds and their sprouts. Since sprouts contain higher concentrations of bioactive compounds and nutrients than seed, germination is a natural alternative to produce ready-to-eat functional foods. Chemical elicitation is a strategy to increase even more the bioactivity of sprouts. CS has been recognized for its beneficial health effects ameliorating dyslipidemia and insulin resistance. This study demonstrates that elicitation, with SA and H2 O2 , during germination of CS, increases the nutrient and phytochemical content of sprouts, with beneficial effects on body weight gain, insulin resistance, dyslipidemia, and prevention of NAFLD progression in diet-induced obese rats. Therefore, chia sprouts, natural and elicited, may be used as potential nutraceutical foods for the prevention and treatment of obesity and its complications.

In vitro conversion of ß-carotene to retinal in bovine rumen fluid by a recombinant ß-carotene- 15, 15'-monooxygenase.

Pasture-fed cattle yield carcasses with yellow fat; consumers often reject the resulting meat products because they assume they come from old and/or culled animals. Recombinant bacteria expressing beta-carotene 15, 15'-monooxygenase, introduced into the rumen of the animal, might help to reduce the coloration since this enzyme converts carotene to retinal, thereby eliminating the source of yellowness. The goal of this work was to evaluate the effect of a recombinant beta-carotene 15, 15'-monooxygenase (BCMO1) from Gallus gallus, expressed in Escherichia coli. The genetically modified microbe was introduced into ruminal fluid, and carotene conversion to retinal was measured. Under optimum conditions the enzyme produced 6.8 nmol of retinal per 1 mg of protein in 1 hour at 37 °C. The data on in vitro digestibility in ruminal fluid showed no differences in beta-carotene breakdown or in retinal production (p > 0.1) between E. coli with pBAD vector alone and E. coli with pBAD/BCMO1. The pBAD/BCMO1 plasmid was stable in E. coli for 750 generations. These results indicate that the protein did not break beta-carotene into retinal in ruminal fluid, perhaps due to its location in the periplasmic space in E. coli. Future research must consider strategies to release the enzyme into the rumen environment.