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

Abstract

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. This study further evaluates the effects of MBP on broilers aged 24-45 d. In this experiment, eight hundred and eighty (880) slow-growing spotted-brown broilers aged 22 d were pre-fed for 2 days, and then randomly divided into two groups according to weight and gender. There were 8 replicates in each group and 55 broilers in each replicate. The trial lasted for 21 d. The broilers in the control group were fed with an antibiotic-free basal diet (denoted as Group D), and the broilers in the experimental group were supplemented with 1% MBP based on an antibiotic-free basal diet (denoted as Group F). The results reveal that, for the growth performance, during 24-45 d, no significant difference is observed between Group F and the control group, 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 F exhibit a significantly higher organ index of the cecum, jejunum villus height, and ratio of villi to crypt, compared to the control group (P<0.05). For the cecal chyme microflora, the abundance ratio of Firmicutes is higher, while the abundance ratio of Bacterodies is relatively lower than that of the control group. The addition of MBP significantly up-regulates the expression abundance of p_Firmicutes, f_Alicyclobacillaceae, g_Acutalibacter, f_Peptococcaceae, f_Clostridiaceae, f_Bacillaceae, g_Enterococcus, f_Enterococcasea, while down-regulates the expression abundance of p_Bacteroidetes, f_Bacteroidaceae, g_Bacteroides, o_Bacteroidales and c_Bacteroidia (P<0.05). For the metabolic pathways, 66 different pathways are observed between Group F and control group, including Alanine, aspartic acid and glutamic acid metabolism, Butyric acid metabolism, Arginine synthesis, Linoleic acid metabolism and β-alanine metabolism. The correlation analysis reveals that Firmicutesin cecal chyme are 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). And the Bacterodiesare positively correlated with some amino acids, including L-Alanine, L-Threonine, 3-Methylthiopropionic acid and L-Glutamic acid (P<0.05). To sum up, 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. It is necessary to further study the effects of MBP on amino acid metabolism and broiler growth by regulating the microflora structure in the chyme.