Possible mechanisms responsible for the reduced intestinal flora in hibernating leopard frogs (Rana pipiens)

Abstract

Mechanisms and factors that normally control the large intestinal flora were investigated to determine whether changes in these parameters could account for the decreased bacterial concentration and facultative nature of the flora found in hibernating frogs. It appeared that low temperatures and limited nutrients were the main factors responsible for the decrease in the bacterial concentration and may also have been responsible for the increase in the proportions of facultative organisms, since no change in the redox potential was seen. The hibernating frogs were extremely sluggish in the removal of India ink particles from the circulatory system by the Kupifer cells of the liver compared with nonhibernating frogs. They were unable to mount an antibody response to bovine serum albumin, but their serum did exhibit killing of Pseudomonas paucimobilis, suggesting opsonization by preformed antibody and complement. The role of these host factors in protecting the hibernating frog against this indigenous flora is discussed.

Unique and shared responses of the gut microbiota to prolonged fasting: a comparative study across five classes of vertebrate hosts

“…Additionally, fasting animals produce less mucus on the gut lining compared with fed animals (Thompson & Applegate, ). These alterations may alter microbial diversity given that several gut microorganisms thrive on mucus (Banas et al ., ; Sonnenburg et al ., ; Martens et al ., ), and differential production of glycans may support the growth of different types of microorganisms (Hooper & Gordon, ; Marcobal et al ., ). Fasted animals also tend to exhibit higher gut pH compared with fed animals (Ward & Coates, ), a chemical difference known to alter microbial growth (Palframan et al ., ).…”

Nutrition and health in amphibian husbandry

“…The role of gastrointestinal microflora on amphibian nutrition is still relatively unclear. Recent work has documented gut microbial communities of salamanders [Okelley et al, 2010] and frogs [Kohl et al, 2013], and has shown that gut microflora varies due to life stage [Kohl et al, 2013] and environmental temperature [Gossling et al, 1982;Banas et al, 1988;Woodhams et al, 2008]. Efforts to utilize probiotics (via water or soil inoculation) are underway to improve amphibian nutrition and health, in particular to mitigate effects of chytridiomycosis [Bletz et al, 2013].…”