Copper-modified palygorskite is effective in preventing and treating diarrhea caused by Salmonella typhimurium

Abstract

Abstract:The aim of this research was to develop effective alternative therapies to reduce antibiotic use in animal agriculture. In this study, the efficacy of copper-modified palygorskite (CM-Pal) in preventing diarrhea caused by Salmonella was specifically examined both in vitro and in vivo. The CM-Pal was prepared with palygorskite (Pal) and copper nitrate. The antibacterial activity of the CM-Pal was detected by comparing the differences in cell numbers on plate count agar before and after adding the CM-Pal to Salmonella typhimurium cultures. Seventy ICR mice were then allocated into seven groups. Five groups (the treatment groups) were infected with S. typhimurium by intraperitoneal (i.p.) injection and were given Pal, CM-Pal, montmorillonite powder, gentamicin, and physiological saline, respectively. One group (the prevention group) was given CM-Pal before infection with S. typhimurium. Another group (the uninfected group) was not infected with S. typhimurium. The effects of Pal, CM-Pal, montmorillonite powder, and gentamicin on the treatment or prevention of diarrhea in the mice were examined by stool studies, fecal scoring, and assessment of growth performance and villus height. The CM-Pal had satisfactory anti-bacterial properties in vitro: the antibacterial rate was 100% after 2 h incubation with S. typhimurium NJS1 cultures (1×10 6 colony-forming units (CFU)/ml). In the in vivo experiment, the CM-Pal exerted superior effects in the treatment and prevention of diarrhea in mice compared with Pal, montmorillonite powder, and gentamicin. In the CM-Pal group, no mice showed signs of diarrhea at 24 h post infection (p.i.), and all mice fully recovered from infection. However, the Pal group, montmorillonite group, and gentamicin group only recovered after 48, 48, and 96 h, respectively. The villus height level in the CM-Pal treatment group recovered at 3 d p.i. However, the recovery time of the other groups was longer (at least 5 d). The CM-Pal prevention group had a better effect on weight gain than the other groups. This study suggested that CM-Pal may be an effective alternative to conventional antibiotics for the treatment and prevention of animal diarrhea caused by Salmonella.

Efficient Stool Collection Methods for Evaluating the Diarrhea Score in Mouse Diarrhea Models

“…The paper towel method was therefore considered efficient and convenient to evaluate the parameters employed in determining diarrhea scores. Some previous studies evaluated the size of the water mark (diarrhea mark) generated on the filter paper as a parameter to determine the diarrhea score (20,63,64). However, the size of the water mark generated on the paper towel by the same amount of instilled water was larger than that on the filter paper in the present study.…”

“…There were only 7 studies that described the feces collection method (Table I). In three of the seven studies, a filter paper was placed on the cage floor without bedding chips to collect stools, and the severity of diarrhea was determined by measuring the size of the diarrhea marks formed on the filter paper (20,63,64). In one study, the bedding chips of the cage were covered with white paper towels to observe the bloody feces (65).…”

“…The size of water absorption marks (water marks) on the paper towel vs. the filter paper. In some previous studies, the severity of diarrhea was evaluated by collecting feces on the filter paper and comparing the size of the water mark (diarrhea mark) generated on the filter paper by absorbing water from wet feces (20,63,64). We evaluated whether the paper towel generates larger or better evaluable water absorption marks (water marks) than the filter paper.…”

“…The feces collection methods used in the searched studies were as follows: A) feces collection using the regular cage containing bedding chips (studies without specific descriptions about the feces collection method), B) feces collection on the filter paper placed on the regular cage floor without bedding chips (20,63,64), C) feces collection on the paper towel placed on the bedding chips in the regular cage (65), D) feces collection using the metabolic cage (62), and E) feces collection while holding the mouse in the hand (19,66).…”

“…In some studies, only two of the three parameters, stool consistency and stool blood, were evaluated to determine DAI (37,40). In other studies, the diarrhea index (DI) was employed to evaluate the severity of diarrhea (20,63,64). DI was calculated by multiplying the diarrhea incidence rate (the number of diarrheal feces ÷ the total number of feces) by the mean loose stool grade.…”