Employment of Phenolic Compounds from Olive Vegetation Water in Broiler Chickens: Effects on Gut Microbiota and on the Shelf Life of Breast Fillets

Abstract

Olive vegetation water (OVW) is a by-product with a noticeable environmental impact; however, its polyphenols may be reused food and feed manufacture as high-value ingredients with antioxidant/antimicrobial activities. The effect of dietary supplementation with OVW polyphenols on the gut microbiota, carcass and breast quality, shelf life, and lipid oxidation in broiler chickens has been studied. Chicks were fed diets supplemented with crude phenolic concentrate (CPC) obtained from OVW (220 and 440 mg/kg phenols equivalent) until reaching commercial size. Cloacal microbial community (rRNA16S sequencing) was monitored during the growth period. Breasts were submitted to culture-dependent and -independent microbiological analyses during their shelf-life. Composition, fatty acid concentration, and lipid oxidation of raw and cooked thawed breasts were measured. Growth performance and gut microbiota were only slightly affected by the dietary treatments, while animal age influenced the cloacal microbiota. The supplementation was found to reduce the shelf life of breasts due to the growth of spoilers. Chemical composition and lipid oxidation were not affected. The hydroxytyrosol (HT) concentration varied from 178.6 to 292.4 ug/kg in breast muscle at the beginning of the shelf-life period. The identification of HT in meat demonstrates that the absorption and metabolism of these compounds was occurring efficiently in the chickens.

Keywords: breast shelf life; broilers; gut microbiota; olive vegetation water; phenolic compounds.

Figure 1

Effect of age on the gut microbiota composition. Significant variation in the relative concentrations of bacterial phyla at 23, 34 and 44 days of age (A), composition of the bacterial community at the family level in all cloacal swab samples (B), and significant variation in the biodiversity at 23, 34, and 44 days of age (C).

Figure 2

(A) Sensory index evaluation of raw breasts. The dotted flat line represents the shelf life threshold (1.8); (B) drip loss; (C) pH value of raw chicken breast meat.

Figure 3

Microbial genera composition (A) and effect of CPC (B) on the microbiota composition of pectoralis major muscles of broiler chickens. In the heat map, the 20 predominant genera are reported (T0 = 24 h, T07 = 168 h; T11 = 264 h).