Effects of Micronized Bamboo Powder on Growth Performance, Intestinal Development, Cecal Chyme Microflora and Metabolic Pathway of Broilers aged 24-45 days

Abstract

Context.Our previous study has revealed that micronized bamboo powder (MBP) can promote the growth performance of broilers aged 1-22 days (d) by improving oxidation resistance, balancing intestinal microflora and regulating metabolic pathways. Aims. This study further evaluates the effects of MBP on the growth performance, intestinal development, cecal chyme microflora and metabolic pathway of broilers aged 24-45 d. Methods.In this experiment, eight hundred and eighty (880) slow-growing spotted-brown broilers aged 22 d were pre-fed for 2 d, and then randomly divided into two groups according to weight and gender. There were 8 replicates in each group and 55 broilers (23 female and 22 male) in each replicate. The trial lasted for 21 d. The broilers in the control group were fed with an antibiotic-free basal diet (Group CON), and the broilers in the experimental group were supplemented with 1% MBP based on the CON diet to replace 1% corn (Group MBP). Key results. For the growth performance, during 24-45 d, no significant difference was observed between Group MBP and Group CON, in average daily gain, average daily feed intake, and the weight gain and feed consumption ratio (P > 0.05). For intestinal development, the broilers in Group MBP exhibited a significantly higher organ index of the cecum, jejunum villus height, and ratio of villi to crypt, compared to Group CON (P < 0.05). For the cecal chyme microflora, the abundance ratio of Firmicutes was higher, while the abundance ratio of Bacterodies was relatively lower than that of Group CON. The addition of MBP significantly up-regulated the abundance of p_Firmicutes, f_Alicyclobacillaceae, g_Acutalibacter, f_Peptococcaceae, f_Clostridiaceae, f_Bacillaceae, g_Enterococcus, f_Enterococcasea, whiledown-regulating the abundance of p_Bacteroidetes, f_Bacteroidaceae, g_Bacteroides, o_Bacteroidales and c_Bacteroidia (P < 0.05). For the metabolic pathways, 66 different pathways were observed between Group MBP and Group CON, including alanine, aspartic acid and glutamic acid metabolism, butyric acid metabolism, arginine synthesis, linoleic acid metabolism and β-alanine metabolism. The correlation analysis revealed that Firmicutesin cecal chyme were significantly positively correlated with some fatty acids, including syringic acid, 3-methyl-2-oxovaleric acid, 3-(2-hydroxyphenyl) propanoic acid, and butyric acid (P < 0.05). The Bacterodieswere positively correlated with some amino acids, including L-Alanine, L-Threonine, 3-Methylthiopropionic acid and L-Glutamic acid (P < 0.05). MBP might be beneficial forcertain fatty acid metabolismand harmful for certain amino acid metabolism by regulating microflora. Conclusions. Taken together, adding 1% MBP to replace corn equivalently has no negative effect on the growth performance of broilers. This may be related to the fact that MBP can improve intestinal development, and increase the content of bacteria that promote fatty acid metabolism and fiber degradation. Implications.MBP can be used as beneficial fiber for broilers. It is necessary to further study the appropriate addition level or alternative of MBP in diet of broilers.