A multi-omics approach to elucidate the mechanisms of action of a dietary muramidase administered to broiler chickens

Abstract

A novel dietary muramidase has been shown to have positive effects on broiler chickens. However, very little is known about its mechanisms of action. The present multi-omics investigation sought to address this knowledge gap. A total of 2,340 day-old male broilers were assigned to 3 groups (12 replicates each) fed, from 0 to 42 d, a basal diet (control group—CON) or the basal diet supplemented with muramidase at 25,000 (low-dose group—MUL) or 45,000 LSU(F)/kg feed (high-dose group—MUH). MUH significantly outperformed CON in terms of cumulative feed intake (4,798 vs 4,705 g), body weight (2,906 vs 2,775 g), and feed conversion ratio (1.686 vs 1.729), while MUL exhibited intermediate performance. At caecal level, MUH showed the lowest alpha diversity, a significantly different beta diversity, a reduction in Firmicutes, and a rise in Bacteroidetes, especially compared with MUL. MUH also exhibited a considerable decrease in Clostridiaceae and an overrepresentation of Bacteroidaceae and Lactobacillaceae. At blood level, MUH had lower hypoxanthine—probably due to its drop at caecal level—histidine, and uracil, while greater pyruvate, 2-oxoglutarate, and glucose. This study sheds light on the mode of action of this muramidase and lays the groundwork for future investigations on its effects on the intestinal ecosystem and systemic metabolism of broiler chickens.

Feeding broiler chickens with arginine above recommended levels: effects on growth performance, metabolism, and intestinal microbiota

“…Caecal samples of ARG birds also showed a decrease in the relative abundance of Firmicutes (e.g., Clostridia) and an increase in the relative abundance of Bacteroidetes (e.g., Bacteroidia). We have recently reported a comparable reduction in caecal alpha diversity and a similar change in the abundance of Firmicutes and Bacteroidetes for high-performing broilers treated with a feed-grade muramidase [38]. Although it is important to take into consideration the differences between the present study and our previous one [38], these findings somewhat contradict the widely known favorable association between microbial diversity or relative abundance of Firmicutes (especially useful Clostridia) and broiler health and performance [90][91][92].…”

“…We have recently reported a comparable reduction in caecal alpha diversity and a similar change in the abundance of Firmicutes and Bacteroidetes for high-performing broilers treated with a feed-grade muramidase [38]. Although it is important to take into consideration the differences between the present study and our previous one [38], these findings somewhat contradict the widely known favorable association between microbial diversity or relative abundance of Firmicutes (especially useful Clostridia) and broiler health and performance [90][91][92]. Remarkably, Singh et al [28] also found increased prevalence of Bacteroidetes in the colon of mice fed on a high-arginine diet.…”

“…The incidence risk ratio was computed on these tables with the package epiR [45] of R [39]. If the incidence risk ratio was significant at 95% confidence interval, the risk of developing the myopathy was calculated as incidence risk ratio minus 1 and expressed in percentage [38].…”

“…Metabolomics analysis of plasma, liver and caecal content was carried out as previously described [38]. Briefly, an 1 H-NMR solution with D 2 O, containing 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid sodium salt (TSP) 10 mmol/L and NaN 3 2 mmol/L was created.…”

Effects of Dietary Coated Lysozyme on the Growth Performance, Antioxidant Activity, Immunity and Gut Health of Weaned Piglets

“…Lysozyme, also known as muramidase or 1,4-β-N-acetylmuramidase, is a natural antibacterial enzyme that is widely detected in saliva, tears and other mammalian secretions [ 17 , 18 ]. It kills bacteria and eliminates pathogens [ 19 , 20 ].…”