Background and Aim: Trimmed asparagus by-products (TABP) is the resultant waste from asparagus possessing. TABP has fructans, such as inulins and fructooligosaccharide, which can be utilized as an alternative prebiotic. This study was conducted to examine the effect of TABP dietary supplementation on the productive performance, nutrient digestibility, gut microbiota, volatile fatty acid (VFA) content, small-intestine histology, and meat quality of broilers.

Materials and Methods: A total of 320 1-day-old broiler chicks (Ross 308^®) were raised under ambient temperature and assigned through a completely randomized design to one of four dietary treatments, with four replicates per treatment. The dietary treatments comprised corn-soybean basal diet supplemented with 0 (control), 10, 30, or 50 g/kg TABP. All birds were provided drinking water and feed ad libitum to meet the standard nutritional requirements of National Research Council for broiler chickens.

Results: TABP supplementation to the broilers significantly increased the apparent ether extract, crude fiber, and gross energy digestibility (p<0.05). TABP supplementation significantly increased lactic bacteria and Enterococcus spp. numbers as well as acetic, propionic, butyric, and total VFA levels (p<0.01); on the other hand, it also significantly decreased Salmonella spp. and Escherichia coli contents in the cecum compared with the control group (p<0.01). Moreover, TABP supplementation increased villus height in the duodenum and jejunum (p<0.01), cryptal depth in the jejunum and ileum (p<0.01), and villus surface areas in the duodenum, jejunum, and ileum (p<0.01). Overall, 0-35 day TABP supplementation significantly increased the feed intake (p<0.01) and average daily gain of broilers (p<0.05), but not significantly affected the viability, productive index, and economic benefit return (p>0.05). The carcass characteristics, pH, color, and water holding capacity of the chicken meat between groups were not significantly different (p>0.05). All levels of TABP supplementation appeared to be a feasible means of producing broilers with the lower serum low-density lipoprotein cholesterol and triglyceride levels as well as atherogenic indices of serum compared with the control (p<0.05). Cholesterol contents and palmitic acid, oleic acid, saturated fatty acids, and Monounsaturated fatty acids levels decreased with an increase of TABP supplementation (p<0.05). Furthermore, TABP supplementation decreased atherogenic index (AI) and thrombogenicity index (TI) of meat (p<0.05).

Conclusion: Supplementation of 30 g/kg TABP in broiler diet could enhance broiler performance and provide chicken meat with beneficial properties, with decreased AI and TI resulted from altered cholesterol and fatty acid profiles.

Keywords: asparagus by-products, broiler, functional feed, functional meat, prebiotic.