Diet influences the ecology of lactic acid bacteria and Escherichia coli along the digestive tract of cattle: neural networks and 16S rDNA

Abstract

In this manuscript, the authors have sought to gain a better understanding of the interactions between Escherichia coli and lactic acid bacteria (LAB) isolated from Rogossa MRS agar along the digestive tract of grain-and forage-fed cattle. E. coli from cattle receiving a high-grain diet were more numerous (P , 0?05) than from the high-forage diet and the highest numbers were in the faeces. Isolates on Rogossa MRS agar were always greater in the high-grain diet (P , 0?05) and contained a significant number of LAB. A random set of Rogossa MRS agar colonies was selected and artificial neural networks were used to develop a relationship between colony description and species which was validated using sequence analysis (16S rDNA). The neural networks correctly predicted species in more than 80 % of cases and was composed, primarily, of Lactobacillus vitulinus, Lactobacillus ruminis, Selenomonas ruminantium, Streptococcus bovis, Acidaminococcus fermentans and Megasphaera elsdenii. In conjunction with statistical diversity indices, it was demonstrated that diversity in the high-fibre diet was always lower and was a consequence of the dominance of Str. bovis. In contrast, the diversity in the high-grain diet was greater (P , 0?05) and was a consequence of the decline in Str. bovis. These data demonstrate that there is a positive relationship between coliform and LAB isolates throughout the digestive tract of cattle, and diet is the major factor regulating bacterial composition.

Aerobe and anaerobe facultative Gram-negative bacteria rod-shaped in the ruminal fluid of dairy cattle fed with different diets containing tropical forages

“…Further researches should clarify if there are inhibitors of these bacteria in sorghum silage, allowing for the achievement of equilibrium and control of these microorganisms in the ruminal environment. Krause et al (2003) evaluated the effects of diet on populations of E. coli and reported a negative relationship between total coliforms and Lactobacillus spp. in the digestive tract of cattle.…”

Coupling of Functional Gene Diversity and Geochemical Data from Environmental Samples

“…Some simulation studies suggest that the test set should be in the range of 5 to 25% of the total number of samples. Examples within most of this range (e.g., 10 to 25%) can be found in the application of ANNs to microbial data (35,44,46).…”

Performance, ruminal changes, behaviour and welfare of growing heifers fed a concentrate diet with or without barley straw

“…These results agree with other authors who observed that enumeration of S. bovis was stable and in low numbers in the rumen of adapted high-grain cattle, except when animals are unadapted to grain or during a rapid transition when there could be a high increase of this bacteria (Olumeyan et al, 1986;Klieve et al, 2003;Nagaraja and Titgemeyer, 2007). Moreover, it is well reported that M. elsdenii is abundant in animals adapted to high grain and it is either not detected or detected in low numbers in animals receiving 100% forage diets (Klieve et al, 2003;Krause et al, 2003;Brown et al, 2006). We also observed an increase of valerate in NBS treatment.…”