Ingestion of Indigestible Cacao Proteins Promotes Defecation and Alters the Intestinal Microbiota in Mice.

Background: In animals, the health effects of ingested cacao proteins are unknown because the proteins are difficult to extract and purify from cacao beans. Objectives: This study aimed to develop an extraction and purification method for cacao proteins and reveal the effect of ingestion of cacao proteins on defecation and intestinal microbiota in mice. Methods: Three groups of mice were fed a control diet (AIN-93 G), a cacao lignin diet (AIN-93 G containing 1.22% cacao lignin), or a cacao protein and lignin diet (AIN-93 G containing 1.97% cacao proteins and 1.22% cacao lignin) by pair-feeding for 8 d. Feces were collected as 2 bulked samples from days 1 to 4 and days 5 to 8 on each diet. The collected feces were weighed and the intestinal microbiota was analyzed by next-generation sequencing-based 16S rRNA. Results: A new extraction and purification method for cacao proteins has been developed, then found that the proteins are resistant to digestive enzymes. However, the cacao protein powder made by this method contained 34.9% of lignin in addition to 56.4% of proteins. Therefore, to reveal the effect by cacao proteins alone, the fecal weight and intestinal microbiota of mice fed the cacao protein and lignin diet were compared with those of mice fed the cacao lignin diet. The fecal weight of mice fed the cacao protein and lignin diet was significantly greater than of mice fed the cacao lignin diet. The relative abundance of Lactococcus and Mucispirillum species in mice fed the cacao protein and lignin diet was significantly higher than in mice fed the cacao lignin diet, but the relative abundance of Anaerotruncus, Oscillospira, and Roseburia species in mice fed the cacao protein and lignin diet was significantly lower than in mice fed the cacao lignin diet. Conclusions: Ingestion of indigestible cacao proteins promoted defecation and altered the intestinal microbiota such as Lactococcus, Mucispirillum, Anaerotruncus, Oscillospira, and Roseburia species in mice.

L233P mutation of the Tax protein strongly correlated with leukemogenicity of bovine leukemia virus.

The bovine leukemia virus (BLV) Tax protein is believed to play a crucial role in leukemogenesis by the virus. BLV usually causes asymptomatic infections in cattle, but only one-third develop persistent lymphocytosis that rarely progress after a long incubation period to lymphoid tumors, namely enzootic bovine leucosis (EBL). In the present study, we demonstrated that the BLV tax genes could be divided into two alleles and developed multiplex PCR detecting an L233P mutation of the Tax protein. Then, in order to define the relationship between the Tax protein and leukemogenicity, we examined 360 tumor samples randomly collected from dairy or breeding cattle in Japan, of which Tax proteins were categorized, for age at the time of diagnosis of EBL. The ages of 288 animals (80.0%) associated with L233-Tax and those of 70 animals (19.4%) with P233-Tax individually followed log-normal distributions. Only the two earliest cases (0.6%) with L233-Tax disobeyed the log-normal distribution. These findings suggest that the animals affected by EBL were infected with the virus at a particular point in life, probably less than a few months after birth. Median age of those with P233-Tax was 22 months older than that with L233-Tax and geometric means exhibited a significant difference (P<0.01). It is also quite unlikely that viruses carrying the particular Tax protein infect older cattle. Here, we conclude that BLV could be divided into two categories on the basis of amino acid at position 233 of the Tax protein, which strongly correlated with leukemogenicity.