Insights into Broilers' Gut Microbiota Fed with Phosphorus, Calcium, and Phytase Supplemented Diets

Abstract

Phytase supplementation in broiler diets is a common practice to improve phosphorus (P) availability and to reduce P loss by excretion. An enhanced P availability, and its concomitant supplementation with calcium (Ca), can affect the structure of the microbial community in the digestive tract of broiler chickens. Here, we aim to distinguish the effects of mineral P, Ca, and phytase on the composition of microbial communities present in the content and the mucosa layer of the gastrointestinal tract (GIT) of broiler chickens.Significant differences were observed between digesta and mucosa samples for the GIT sections studied (p = 0.001). The analyses of 56 individual birds showed a high microbial composition variability within the replicates of the same diet. The average similarity within replicates of digesta and mucosa samples across all diets ranged from 29 to 82% in crop, 19–49% in ileum, and 17–39% in caeca. Broilers fed with a diet only supplemented with Ca had the lowest body weight gain and feed conversion values while diets supplemented with P showed the best performance results. An effect of each diet on crop mucosa samples was observed, however, similar results were not obtained from digesta samples. Microbial communities colonizing the ileum mucosa samples were affected by P supplementation. Caeca-derived samples showed the highest microbial diversity when compared to the other GIT sections and the most prominent phylotypes were related to genus Faecalibacterium and Pseudoflavonifractor, known for their influence on gut health and as butyrate producers. Lower microbial diversity in crop digesta was linked to lower growth performance of birds fed with a diet only supplemented with Ca. Each diet affected microbial communities within individual sections, however, no diet showed a comprehensive effect across all GIT sections, which can primarily be attributed to the great variability among replicates. The substantial community differences between digesta and mucosa derived samples indicate that both habitats have to be considered when the influence of diet on the gut microbiota, broiler growth performance, and animal health is investigated.

Development of the Ileal Microbiota in Three Broiler Breeds

“…Other taxa identified as differentially abundant in the mucus were those previously classified as associated with the caecal microbiome such as Lachnospiraceae, Ruminococcaceae, Peptococcaceae, and Bacteroidaceae. A similar result was obtained by Borda-Molina et al (21) who found Lachnospiraceae, Ruminococcaceae, and Burkholderiaceae to be more prevalent in the crop and ileal mucosa compared to digesta. Their presence in the ileum may be due to ingestion of these bacteria from the feces of other birds or retroperistalsis from the caecum.…”

“…Candidatus Athromitus is also increasingly identified within the early ileal microbiome and has been associated with increased performance although later colonization with this taxa is associated with poor performance (20). There is also evidence to suggest that the mucus associated microbiome is different to the luminal microbiome with a lower relative abundance of Lactobacillaceae and a more diverse microbiota including Peptostreptococcaceae, Lachnospiraceae, Burkholderiaceae, and Ruminococcaceae (16,21).…”

Association between the gut microbiota and mineral metabolism

“…A diet rich in calcium, calcium with a probiotic, or calcium with a probiotic and lactose has caused a significant increase in lactic acid bacteria and coliform bacteria in chickens . However, the probiotic properties of calcium are not as great as those of phosphorus, which not only influences the gut microbiota but also positively affects the host's growth . The supply of the probiotic bacterium L. reuteri in mice predisposed to type 1 diabetes results in a reversal of type 1 diabetes‐mediated bone loss .…”

“…71 However, the probiotic properties of calcium are not as great as those of phosphorus, which not only influences the gut microbiota but also positively affects the host's growth. 72 The supply of the probiotic bacterium L. reuteri in mice predisposed to type 1 diabetes results in a reversal of type 1 diabetes-mediated bone loss. 73 Supplying Saccharomyces cerevisiae in rats results in a decrease in the concentration of tumor necrosis factor (TNF) and interleukin-1 (IL-1 ) and an increase in the concentration of the anti-inflammatory cytokine interleukin-10 (IL-10), which decreases calcium loss from tooth tissue and positively affects the hard teeth repair process.…”

Untitled

“…The active fractions were pooled and allowed to stand at 4 °C. The pure form of the enzyme was thus obtained 28 .…”