Interactive Effects of Indigestible Carbohydrates, Protein Type, and Protein Level on Biomarkers of Large Intestine Health in Rats

Abstract

The effects of indigestible carbohydrates, protein type, and protein level on large intestine health were examined in rats. For 21 days, 12 groups of six 12-week-old male Wistar rats were fed diets with casein (CAS), or potato protein concentrate (PPC), providing 14% (lower protein level; LP), or 20% (higher protein level; HP) protein, and containing cellulose, resistant potato starch, or pectin. Fermentation end-products, pH, and β-glucuronidase levels in cecal digesta, and ammonia levels in colonic digesta were determined. Cecal digesta, tissue weights, cecal and colon morphology, and colonocyte DNA damage were also analyzed. Digesta pH was lower, whereas relative mass of cecal tissue and digesta were higher in rats fed pectin diets than in those fed cellulose. Cecal parameters were greater in rats fed PPC and HP diets than in those fed CAS and LP diets, respectively. Short-chain fatty acid (SCFA) concentrations were unaffected by protein or carbohydrate type. Total SCFA, acetic acid, and propionic acid concentrations were greater in rats fed LP diets than in those fed HP. Cecal pool of isobutyric and isovaleric acids was greater in rats fed PPC than in those fed CAS diets. PPC diets decreased phenol concentration and increased ammonia concentration in cecal and colonic digesta, respectively. Cecal crypt depth was greater in rats fed PPC and HP diets, and was unaffected by carbohydrates; whereas colonic crypt depth was greater in rats fed cellulose. Myenteron thickness in the cecum was unaffected by nutrition, but was greater in the colon of rats fed cellulose. Colonocyte DNA damage was greater in rats fed LP diets than in those fed HP diets, and was unaffected by carbohydrate or protein type. It was found that nutritional factors decreasing cecal digesta weight contribute to greater phenol production, increased DNA damage, and reduced ammonia concentration in the colon.

Continuous combined intake of polydextrose and lactitol stimulates cecal fermentation and salivary IgA secretion in rats

“…2). These findings are consistent with a previous report in which the consumption of indigestible carbohydrates induced fermentation in the cecum (24), which has been shown to positively affect microbial composition and immune responses in the large intestine of rats (17). The upregulation of IgA secretion in the cecum is caused by various antigens, such as bacterial cell wall constituents or decomposed and fermented products of indigestible carbohydrates, generated as a result of increased fermentation by intestinal microflora (25).…”

Effect of diets varying in the type of dietary fibre and its combination with polyphenols on gut function, microbial activity and antioxidant status in rats

“…It was also revealed that supplementing rats with PEC, and to a lesser extent POM, increased the small intestinal mass. Other researchers have also shown a similar effect of pectin (Pirman et al, 2007;Taciak et al, 2015), which may result from accumulation of a high-moisture and viscous digesta and from its prolonged passage through the proximal part of the digestive tract. Pectin increased also maltase activity in the small intestine, which might be an adaptive response to greater digesta weight and viscosity but also to morphological changes as it was indicated by Schwarz et al (1983) and Koruda et al (1988).…”

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

“…Despite this, adding resistant starch to these high protein diets nullified the negative effects of high protein consumption [135], further illustrating the importance of consuming adequate dietary fiber for gut and overall health. Another study examined the effects of protein type, and protein level on large intestine health in rats [136]. Lower levels of cecal BCAA were found in rats who ate a lower protein diet (14% of total energy) than those who consumed a high protein diet (20% of total energy) [136].…”

“…Another study examined the effects of protein type, and protein level on large intestine health in rats [136]. Lower levels of cecal BCAA were found in rats who ate a lower protein diet (14% of total energy) than those who consumed a high protein diet (20% of total energy) [136]. These authors also showed that plant-based protein proved to be beneficial compared to animal protein, where potato protein concentrate (PPC) consumption positively impacted colonic health by reducing enzymatic activity of β-glucuronidase, which is a biomarker for the risk of carcinogenesis [136].…”

“…Lower levels of cecal BCAA were found in rats who ate a lower protein diet (14% of total energy) than those who consumed a high protein diet (20% of total energy) [136]. These authors also showed that plant-based protein proved to be beneficial compared to animal protein, where potato protein concentrate (PPC) consumption positively impacted colonic health by reducing enzymatic activity of β-glucuronidase, which is a biomarker for the risk of carcinogenesis [136]. The rats that ate PPC and low protein diets also presented deeper cecal crypts, illustrating that they had more cell proliferation and renewal which is necessary for epithelial repair [136].…”