Effect of cereal type and plant extract addition on the growth performance, intestinal morphology, caecal microflora, and gut barriers gene expression of broiler chickens.

Feeding broiler chickens on diets based on cereal grains of high non-starch polysaccharides content such as wheat and barley can negatively impact their performance and gut health. Plant extracts can be used as a potential tool to alleviate these negative effects. The present study assessed the effects of dietary cereal type and the inclusion of a plant extract blend (PEB) on the growth performance, intestinal histomorphology, caecal microflora, and gene expression of selected biomarkers for gut integrity in broiler chickens in a 42-d experiment. Ross-308 male broilers were assigned into different dietary treatments and fed on two cereal types (corn- vs. wheat/barley-based) with/without added graded concentrations of a PEB (0, 250, 500, 1000, and 2000 mg/kg diet). There were no significant differences in the growth performance parameters, intestinal histomorphology, and caecal microflora due to the impact of dietary cereal type. However, lactobacilli count in the caecal microflora was increased in the group fed on a corn-based diet. The PEB supplementation especially at a level of 500 to 1000 mg/kg diet significantly increased the average BW and decreased the feed conversion ratio. It also increased the villi length of duodenum, jejunum, and ileum, decreased the duodenal crypt depth, and increased the villi length to crypt depth ratio in the duodenum, jejunum and ileum. Supplementation of the PEB decreased the total bacterial and coliform count and increased the lactobacilli count in a linear pattern. Gene expression of Occludin and Junction Adhesion Molecule was significantly increased in the PEB supplemented diets, whereby no influence was observed on mucin expression. In conclusion, supplementation of a PEB at levels of 500-1000 mg/kg can be used as a tool to improve broiler performance and gut health.

Marjoram extract down-regulates the expression of Pasteurella multocida adhesion, colonization and toxin genes: A potential mechanism for its antimicrobial activity.

Due to the emergence of virulent and antibiotic-resistant microbes, natural antimicrobials from herbal origins have been given more attention as an alternative therapy. This study provides an in vitro research framework to investigate the antibacterial activities of 5 herbal (marjoram, garlic, onion, cinnamon and black seed) oil extracts against 16 multidrug-resistant (MDR) and virulent P. multocida serogroup A isolates recovered from dead and clinically diseased rabbits. Pathogenicity of the screened isolates was further proven experimentally and was verified by PCR analyses of 5 randomly selected virulence genes encoding attachment and colonization proteins (ptfA, pfhA, and omp87), sialidases (nanB) and dermonecrotoxin (toxA). A total of 12 P. multocida isolates were highly pathogenic with the possession of all examined virulence genes, while the other 4 isolates were of lower pathogenicity with expression of the target genes except toxA. In vitro anti-P. multocida activities of the 5 extracts and their synergism rates with 4 antibiotic drugs revealed that marjoram and cinnamon extracts had the highest antibacterial activities and the highest synergism rates against the screened isolates. Pasteurella multocida virulence gene expression profiles were assessed via real-time quantitative reverse transcription PCR (qRT-PCR) in response to marjoram extract. The quantitative analyses showed less than five-fold reduction in the targeted virulence genes expression in presence of marjoram extract compared with the control. The findings from this study document a novel molecular inhibitory activity of marjoram against P. multocida multiple virulence genes and provide a proof of concept for its implementation as an alternative candidate for the treatment of pasteurellosis in farm animals in future.

The effects of the dietary supplementation of Echinacea purpurea extract and/or vitamin C on the intestinal histomorphology, phagocytic activity, and gene expression of the Nile tilapia.

In this study, the influence of the dietary incorporation of Echinacea purpurea (EP) extract and/or vitamin C on the intestinal histomorphology and some immunological indices were tested in the Nile tilapia (Oreochromis niloticus Linn.). O. niloticus were randomly divided into four groups. The control group G1 was fed on a basal diet, while the G2 and G3 were fed on basal diets, supplemented with EP extract and vitamin C at the doses of 500 mg kg-1 and 400 mg kg-1, respectively. Meanwhile, G4 was fed on a basal diet, supplemented with a mixture of EP extract and vitamin C. After 28 days of feeding, the intestinal tissues were collected for histological observation and immune status, was based on an assay for measuring the phagocytic activity. Furthermore, the expression of the transforming growth factor-beta 1 (TGF-ß1), interleukin-1beta (IL-1ß), and tumor necrosis factor alpha (TNF-α) genes was evaluated in intestine and head kidney. The results revealed that the G4 successfully surpassed the other groups in terms of the heights of intestinal villi, the number of goblet cells and intraepithelial lymphocytes (IELs), and the phagocytic activity, followed by the G3 and G2. The expression of the IL-1ß and TNF-α genes were up regulated only in G4 but in the G3 only the expression of the IL-1ß gene was up regulated. Hence, EP extract along with vitamin C could be used as a feed additive in order to improve the structure of the intestinal mucosal epithelium and immune response in tilapia.