Effect of anaerobic fungi on glycoside hydrolase and polysaccharide depolymerase activities, in sacco straw degradation and volatile fatty acid concentrations in the rumen of gnotobiotically reared lambs

Abstract

Summary ― Four naturally born lambs were placed in sterile isolators 24 h after birth, before the natural establishment of the cellulolytic microorganisms. At the age of 4 weeks, a cellulolytic bacterial population of approximately 10 a cells g-1 of rumen contents was established by inoculation with a 10-6 dilution of ruminal contents taken from an adult sheep. A pure culture of Neocallimastix frontalis MCH 3 and Piromyces communis FL was inoculated into the rumen 5 months after birth and a stable population of 10 3 -10 4 zoospores g-1 developed; the cellulolytic bacteria and fungi established populations in the 4 lambs that were similar to those observed in conventional animals. The presence of fungi led to an increase in the activity of most of the glycoside and polysaccharide hydrolases of the particle-associated microbial populations. However, this effect was not acompanied by an increase in the in sacco degradation of wheat straw or an increase in the volatile fatty acid concentration in the rumen contents.

The Rumen Microbial Ecosystem

“…With straw, their individual cellulolytic activity, as well as that of the mixed fungal population, was less than that of the conventional controls. Interrelationships between fungi and cellulolytic bacteria have been investigated using two animal models (Williams et ai., 1994;Fonty et al, 1995). After 72 h the degradation of the plant tissues was similar to that in conventional controls (Grenet et ai., 1989).…”

Use of Yeast Probiotics in Ruminants: Effects and Mechanisms of Action on Rumen pH, Fibre Degradation, and Microbiota According to the Diet

“…Moreover, thanks to the development of a rhizoidal network they are able to weaken and even disrupt plant tissue which enhances accessibility to digestible structures [114]. Studies carried out with gnotoxenic lambs harbouring or not fungi confirmed their important role in fibre breakdown in the rumen [115].…”

Ultrasonic Degradation of Polysaccharide from a Red Algae (Porphyra yezoensis)

“…Because the average molecular weight of native polysaccharides is determined by their source of origin and cannot be, in most cases, easily degraded, it is necessary to set up a kind of fast, efficient, and convenient method of degrading the native polysaccharides in order to achieve the desired molecular weight (). Chemical treatment, such as acid or alkali hydrolysis ( − ), is often used, but its consumption of solvents and energy is vast and chemical wastes are often unavoidable. So, the physical degradation method of polysaccharide is potentially likely.…”