Effects of in ovo injection of Astragalus kahericus polysaccharide on early growth, carcass weights and blood metabolites in broiler chickens

Astragalus polysaccharide: implication for intestinal barrier, anti-inflammation, and animal production

Intestine is responsible for nutrients absorption and plays a key role in defending against various dietary allergens, antigens, toxins, and pathogens. Accumulating evidence reported a critical role of intestine in maintaining animal and human health. Since the use of antibiotics as growth promoters in animal feed has been restricted in many countries, alternatives to antibiotics have been globally investigated, and polysaccharides are considered as environmentally friendly and promising alternatives to improve intestinal health, which has become a research hotspot due to its antibiotic substitution effect. Astragalus polysaccharide (APS), a biological macromolecule, is extracted from astragalus and has been reported to exhibit complex biological activities involved in intestinal barrier integrity maintenance, intestinal microbiota regulation, short-chain fatty acids (SCFAs) production, and immune response regulation, which are critical for intestine health. The biological activity of APS is related to its chemical structure. In this review, we outlined the source and structure of APS, highlighted recent findings on the regulation of APS on physical barrier, biochemical barrier, immunological barrier, and immune response as well as the latest progress of APS as an antibiotic substitute in animal production. We hope this review could provide scientific basis and new insights for the application of APS in nutrition, clinical medicine and health by understanding particular effects of APS on intestine health, anti-inflammation, and animal production.

The use of Astragalus membranaceus as an eco-friendly alternative for antibiotics in diets of Japanese quail breeders

Mature Japanese quails (n. 180), aged 8 wk, were divided into 6 groups to evaluate the influence of dietary Astragalus membranaceus powder on laying and reproductive performances, quality of egg, and blood metabolites. A completely randomized design experiment was performed including 6 groups. The first group of quails was served as control (basal diet). While, the 2nd, 3rd, 4th, 5th, and 6th group of quails fed a basal diet supplemented with 1, 2, 3, 4, and 5 g of AM powder/kg diet, respectively. Egg number (EN), weight (EW), and mass (EM) were not significantly influenced by dietary Astragalus membranaceus at all tested levels. The hatchability percentage was quadratically improved by dietary supplementation of A. membranaceus. Dietary supplementation of A. membranaceus positively affects (linear and quadratic) liver and kidney functions. Plasma total cholesterol (TC; P < 0.001) and Triglyceride (TG; P < 0.001) were linearly and quadratically decreased by dietary A. membranaceus increasing level. Blood urea level decreased with increasing A. membranaceus levels in the quail diet. The immunoglobulin G (IgG) and M (IgM) were higher than the control at all A. membranaceus levels. In conclusion, feeding quail breeders with Astragalus membranaceus at 1 g/kg diet has beneficial effects on feed conversion ratio; on production at 2 g/kg diet; on hatchability and immunity at 5 g/kg diet; and on total cholesterol at 3 g/kg diet and on shell quality at 4 g/kg diet. A. membranaceus products are expected to be novel valuable dietary supplements for poultry production, depending on the target trait.

Managing Gut Microbiota through In Ovo Nutrition Influences Early-Life Programming in Broiler Chickens

The chicken gut is the habitat to trillions of microorganisms that affect physiological functions and immune status through metabolic activities and host interaction. Gut microbiota research previously focused on inflammation; however, it is now clear that these microbial communities play an essential role in maintaining normal homeostatic conditions by regulating the immune system. In addition, the microbiota helps reduce and prevent pathogen colonization of the gut via the mechanism of competitive exclusion and the synthesis of bactericidal molecules. Under commercial conditions, newly hatched chicks have access to feed after 36-72 h of hatching due to the hatch window and routine hatchery practices. This delay adversely affects the potential inoculation of the healthy microbiota and impairs the development and maturation of muscle, the immune system, and the gastrointestinal tract (GIT). Modulating the gut microbiota has been proposed as a potential strategy for improving host health and productivity and avoiding undesirable effects on gut health and the immune system. Using early-life programming via in ovo stimulation with probiotics and prebiotics, it may be possible to avoid selected metabolic disorders, poor immunity, and pathogen resistance, which the broiler industry now faces due to commercial hatching and selection pressures imposed by an increasingly demanding market.

Proper Immune Response Depends on Early Exposure to Gut Microbiota in Broiler Chicks

The successional changes in the early intestinal microbiota occur concomitantly with the development, expansion, and education of the mucosal immune system. Although great attention of researchers has been focused on understanding the linkage between microbiota and immune functions, many essential details of the symbiotic relationship between the intestinal pioneer microbiota and the avian immune system remain to be discovered. This study was conducted to understand the impact of different early life intestinal colonizers on innate and adaptive immune processes in chicks and further identify immune-associated proteins expressed in the intestinal tissue. To accomplish it, we performed an in ovo application of two apathogenic Enterobacteriaceae isolates and lactic acid bacteria (L) to determine their influences on the intestinal proteome profile of broilers at the day of hatch (DOH) and at 10 days old. The results indicated that there were predicted biological functions of L-treated chicks associated with the activation and balanced function of the innate and adaptive immune systems. At the same time, the Enterobacteriaceae-exposed birds presented dysregulated immunological mechanisms or downregulated processes related to immune development. Those findings suggested that a proper immune function was dependent on specific gut microbiota exposure, in which the prenatal probiotic application may have favored the fitting programming of immune functions in chicks.