Effect of feeding different levels of lignocellulose on performance, nutrient digestibility, excreta dry matter, and intestinal microbiota in slow growing broilers

Abstract

Lignocellulose is a constituent of plant cell walls and might be used as a fiber source in poultry nutrition. The current study investigated the impact of increasing dietary levels of lignocellulose on performance, nutrient digestibility, excreta DM, intestinal microbiota, and bacterial metabolites in slow growing broilers. At an age of 10 wk, 60 male broilers of an intercross line (New Hampshire × White Leghorn) were allocated to cages and fed isoenergetic and isonitrogenous diets containing 0.8% ( LC1 ), 5% ( LC2 ), or 10% ( LC3 ) lignocellulose. After 23 D of feeding, broilers were killed and digesta samples of ileum and excreta analyzed for nutrient digestibility and DM. Cecal contents were analyzed for microbial composition and metabolites. Broiler performance was not affected by feeding dietary lignocellulose. LC3 fed broilers showed reduced ileal digestibility of protein compared to chickens fed LC1 ( P = 0.003). Moreover, increasing levels of dietary lignocellulose reduced apparent digestibility of organic matter and gross energy ( P < 0.001). Feeding of lignocellulose had no impact on the excreta DM of broilers. Increasing levels of dietary lignocellulose lowered cecal counts of Escherichia / Hafnia / Shigella ( P = 0.029) and reduced the total concentration of short-chain fatty acids ( P < 0.001), lactate ( P < 0.05), and ammonia ( P = 0.009). The molar ratio of cecal acetic acid was higher in LC3 fed broilers ( P < 0.001), while the proportions of cecal propionic acid and n-butyric acid were higher in LC1 and LC2 fed chickens ( P < 0.001). Correlation analyses indicated that dietary lignocellulose was negatively related to the total concentration of cecal bacterial metabolites ( P < 0.001). In conclusion, the feeding of lignocellulose did not affect growth performance, but impaired nutrient digestibility of slow growing broilers. While minor changes in cecal microbial composition were detected, cecal bacterial metabolite concentrations were significantly reduced with increasing levels of dietary lignocellulose. These findings suggest that lignocellulose is not extensively degraded by bacteria residing in the large intestine of broilers.

Lignocellulose as an insoluble fiber source in poultry nutrition: a review

“…Finally but yet importantly, the particle size of a fiber source is another key characteristic, which may influence digestive function [ 23 ]. After processing and fiber breakdown, LC is a powdery material with an average particle size of 80 to 300 μm [ 22 , 25 ]. This material can then be further processed, so that various LC products are commercially available, e.g.…”

“…Broilers fed diets diluted with relatively high concentrations of LC of 5% to 15% showed a marked decrease in average daily gain with increasing concentrations of dietary LC, while feed intake tended to increase with increasing concentrations of LC [ 31 ]. On the contrary, broiler productivity seems to be unaffected by relatively high dietary LC inclusion levels up to 10% when diets were composed to be isoenergetic and isonitrogenous [ 25 , 39 ].…”

“…In contrast, the supplementation of 1% or 2% dietary LC did not affect protein and gross energy digestibility in broilers [ 24 , 29 ]. Feeding of isoenergetic and isonitrogenous diets with higher LC inclusion levels of 5% and 10% led to a decrease in the apparent ileal digestibility of crude protein and apparent excreta digestibility of organic matter and gross energy while the total tract digestibility of ether extract was not affected [ 25 ]. The apparent ileal fat digestibility and total tract digestibility of total fatty acids in broilers was also not influenced by the supplementation of 0.25% and 0.5% LC while the feeding of 1% LC resulted in an increased apparent fat digestibility [ 53 ].…”

“…Consistent with the latter, laying hens fed 10% LC for 52 weeks had a higher excreta DM content at 10, 17 and 22 weeks of age compared to those fed the control diet [ 70 ]. However, studies in broilers showed no impact of dietary LC on excreta scoring or excreta DM [ 22 , 25 ].…”

“…Few studies used the same LC product, but different LC inclusion levels and feed formulations [ 25 , 27 , 30 , 70 ]. The feeding of diets supplemented with LC at relatively low inclusion levels of 0.25% to 0.6% reduced counts of Escherichia coli and Clostridium perfringens and increased those of Bifidobacterium spp.…”