doi:?10

doi:?10.1016/j.aninu.2017.03.004. extracted from impaired growth overall performance in broilers, as indicated by the observed decreases in body weight (((is one of the most harmful pathogens in poultry, leading to high economic losses in developing countries because of its considerable transmission routes [1]. can cause intestinal injury, acute systemic disease, compromised production performance, and high mortality in young chickens [2]. In the past several decades, antibiotics have been utilized for the prevention and treatment of pathogenic infections. However, with the widespread use of antibiotics in livestock production, antibiotic resistance is usually a growing threat to food security and public health [3]. Therefore, safe and effective option treatment strategies BT-13 are necessary. In recent years, plant extracts have been used as potential approaches to protect poultry against bacterial difficulties [4, 5]. Magnolol and its isomer honokiol are the main phenolic substances extracted from the root and bark of (SPH); and (4) chicks that received a diet supplemented with 300?mg/kg magnolol and treated with (SPM). The basal diet was a standard maize/soybean meal diet (Additional?file?1). The chicks of each replicate were housed in wire cages (100 cm??70?cm??60?cm) in an environmentally controlled house. The CTL group and challenge BT-13 group cages were kept at a certain distance and reared separately to prevent contamination. The trial lasted for 21 d. Oral challenge and overall performance The frozen stain (C79C3) was thawed and cultured in Luria-Bertani (LB) broth to activate for three times (37?C, 16?h). After activating bacteria, expanding propagating and centrifugation, was resuspended in sterilized PBS and counted by plate cultivation. Chicks in the SP, SPH, and SPM groups were orally treated with a 0.5?mL (4??108?CFU/mL) solution at 5?days of age, while chicks in the CTL group received the same amount of sterilized PBS at the same age. Sample collection The supplied and residual feed intakes of each replicate were recorded weekly to calculate the feed conversion ratio (FCR) and average daily feed intake (ADFI). Body weight (BW) and average daily gain (ADG) were measured on days 14 and d?21. At 14 and 21?days of age, 1 chick from each replicate was randomly selected to be weighed and BT-13 slaughtered by jugular exsanguination after a 12-h fasting period. The weights of the liver, spleen, and bursa of Fabricus were recorded. Blood samples were collected and centrifuged to separate the serum samples. A 1-cm long section from your distal parts of the BT-13 jejunum and ileum was collected and fixed in a 10% neutral buffered formalin Rabbit Polyclonal to DNA Polymerase lambda answer for the histological studies. The tissue and content samples of the ileum were collected and frozen in liquid nitrogen until their use. Analyses of serum biochemical indices Total protein (TP), albumin, globulin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and triglyceride were determined using a colorimetric method (UV-2550, Shimadzu, Japan) with the aid of a commercial kit (Nanjing Jiancheng Institute of Bioengineering, Jiangsu, China). Histological studies After being fixed in the formalin answer for 24?h, the intestinal tissues were embedded in paraffin and sectioned. The sections were then stained with hematoxylin and eosin (HE). Eight total intestinal villi of each slice were randomly selected to measure the villus height, crypt depth, and thickness of the intestinal muscularis using a micro-image processing system (Shineso, Hangzhou, China). 16S rDNA gene sequencing of the ileum microbiome The microbial genomic DNA extraction from your cecal content BT-13 samples was carried out using the hexadecyltrimethylammonium bromide (CTAB) method. Using genomic DNA with the required purity and concentration as themes, the V3 and V4 hypervariable regions of the microbial 16S rDNA gene were amplified using primers 341F (5-CCTACGGGRBGCASCAG-3) and 806R (5- GGACTACNNGGGTATCTAAT-3). The indexed adapters were added to the ends of the 16S rDNA amplicons to generate indexed libraries ready for sequencing on an Illumina NovaSeq 6000 platform (Illumina, San Diego, USA) performed by Novogene Co., Ltd. (Beijing, China). The obtained clean sequences were aligned into operational taxonomic models (OTUs) with a 97% similarity. A species annotation analysis was carried out against the OUTs using the SSUrRNA database of Silva 123.