Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise.

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Brazilian beef produced on pastures: sustainable and healthy.

With a herd of 209 million cattle, Brazilian beef production estimate for 2023 is 10,935 million tons, representing an increase of 28.9% and accounting for 20% of the world trade. Beef cattle production is constantly evolving; however, there are extremes, ranging from simple existing farm ranges to intensive forage systems, strategic supplementation, updated health and genetic improvement programs for the production of quality beef. This modern production is based on scientific research carried out at universities and other research institutions. A new generation of professionals with multidisciplinary knowledge and a holistic vision of the productive chain-proposed management practices to reduce greenhouse gas emissions in the production of grass-fed beef cattle, whose meat has high omega-3 and CLA contents. Age at slaughter of steers and of heifers at first mating, significant increases in the ratio calves/100 cows, adequate traceability for pastoral systems with hundreds or thousands of animals per farm and a more intense transference of technology are required.

Nutritional composition of the meat of Hereford and Braford steers finished on pastures or in a feedlot in southern Brazil.

Chemical and mineral composition and the intramuscular fatty acid (IMF) profile of the Longissimus dorsi muscle (LM) of 60 purebred Hereford, 1/4 Braford and 3/8 Braford steers finished either in a feedlot or on improved pastures of the Pampa biome were evaluated. Pastures were improved with the introduction of Lolium multiflorum, Trifolium repens, and Lotus corniculatus. On average, beef from pasture-fed steers presented higher concentrations of the fatty acids C18:3n-3 (P<0.001), C20:3n-3 (P=0.035), total n-3 (P<0.001) and lower n-6/n-3 ratio (P<0.001) in the IMF, and higher Mg and lower K content in muscle relative to those finished in the feedlot. C12:0 concentration in IMF was higher (P=0.027) for 3/8 Braford than the purebred Hereford steers, whereas purebred Herefords presented lower C14:1 (P=0.003) and higher C18:0 (P=0.022) concentrations than the two Braford groups. The meat composition of purebred Hereford and Braford steers was not substantially different; however, beef produced exclusively on improved pastures presented higher concentration of components that are considered beneficial to human health, such as n-3 fatty acids, and a lower n-6/n-3 ratio.