This study evaluated the effect of quercetin (Q) added to feed mixtures, at concentrations directly optimized for the peroxidability of dietary rapeseed (RO) and flaxseed oil (FLO), on performance and selected biomarkers of oxidative stress of broiler chickens. Ninety-six one-day-old Ross 308 broiler chicken males were randomly assigned to four groups (six replicates per treatment, four birds per cage, n = 24 per group): Group RO received diets containing rapeseed oil (RO) and group FLO received diets containing flaxseed oil (FLO); Group RO_Q and group FLO_Q received these same diets containing RO or FLO oils, supplemented with optimized quercetin (Q). Blood, pectoral muscles, and liver samples of chickens were collected after 35 days to determine: (1) the global indicators of antioxidant capacity: ferric reducing antioxidant power (FRAP), antiradical activity (DPPH^·/ABTS^·+), total antioxidant status (TAS), and glutathione peroxidase (GSH-Px); (2) the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD); and (3) the concentration of malondialdehyde (MDA). Data showed that the FLO diet did not affect the final performance parameters in relation to RO, but the optimized Q tended to improve the total body weight gain and the final body weight of broiler chickens (P = 0.10). The antioxidant traces analyzed in the blood (GSH-Px), plasma (FRAP, ABTS^·+, DPPH^·, TAS), serum (DPPH^·), and pectoral muscles (SOD, CAT) of chickens were not altered by either Oil or Q factor. FLO supplementation increased MDA content in the liver of chickens (P < 0.05) and increased liver CAT activity, which was not improved by optimized Q. Meanwhile, the Oil × Q interaction suggests that optimized Q could reduce the liver burden and negative effects of oxidized lipid by-products associated with FLO diets. Our results indicate that optimizing the addition of natural polyphenols to feed may be a valuable alternative to the application of polyphenolic antioxidants in animal nutrition, allowing for an economical use of the antioxidant additives when customized to the peroxidability of fat sources, which is line to the conception of sustainable development covering ‘The European Green Deal’ and ‘Farm to Fork Strategy’.

Background: Poor hygiene of housing induces a systemic inflammatory response. Because inflammation and oxidative stress are processes that can sustain each other, the ways pigs are able to activate their antioxidant defenses are critical for production performance and health during periods when the immune system is solicited. Selection for production performance can also influence reactive oxygen species (ROS) production and expression levels of genes involved in cellular response to oxidative stress in different tissues. To establish the extent by which poor hygiene and selection for feed efficiency affected redox status, pigs divergently selected for residual feed intake (RFI) were housed in poor or good hygiene during 6 weeks. At the end, blood was collected in all pigs, and half of them were killed for tissue sampling. The remaining pigs were reared in good hygiene conditions during a recovery period of 7–8 weeks.Results: At week 6, poor hygiene was associated with a lower total antioxidant capacity assessed by plasma ferric reducing ability in all pigs, and with greater plasma levels of hydrogen peroxides in the high RFI pigs (less efficient). Adipose tissue of high RFI pigs exhibited higher activities of catalase and glutathione reductase, and greater thiobarbituric acid reactive substances (TBARS) concentrations when compared with the low RFI pigs (more efficient). Poor hygiene conditions activated the antioxidant enzymes activities (glutathione reductase, superoxide dismutase and catalase) in adipose tissue of both lines, but led to higher ROS production by mature adipocytes isolated from the high RFI pigs only. In liver and muscle, there were only minor changes in antioxidant molecules due to genetics and hygiene conditions. After the resilience period, adipose tissue of pigs previously challenged by poor hygiene maintained higher antioxidant enzyme activities, and for the high RFI line, displayed higher TBARS concentrations.Conclusions: Pigs selected for improved feed efficiency showed a lower susceptibility to oxidative stress induced by poor hygiene conditions. This could led to a lower inflammatory response and less impaired growth when these pigs are facing sanitary challenges during the production period.

The effects of dietary supplementation with extracts of rosemary (RO) and blackcurrant (BC) on the performance indices and the oxidative stability of broiler meat were investigated during a 35-d experiment. For the experiment, 120 one-day-old male Hubbard Flex broiler chicks were randomly allocated to 5 experimental groups (control group and 4 treatments, each in 6 replications, 24 birds per group, 4 birds per replicate) and fed control starter and grower diets or basal diets containing two concentrations (2.5 and 5 g/kg) of the RO and BC extracts. Basic performance traits (body weight gain, feed intake, feed conversion) were recorded during the trial. At the end of the experiment, pectoral and thigh muscles were collected. Thiobarbituric acid (TBA) assays using the muscles samples were performed after 1 and 5 d of chilling (4 °C) and after 90 d of frozen storage (−18 °C). The inclusion of RO and BC in the birds’ diet had no significant effects on weight gain and feed conversion ratio of chickens, or on carcass characteristics, compared with control group. Enrichment of chicken diet with RO and BC did not affect the oxidative stability of chicken breast muscles, but the tested extracts significantly reduced the malondialdehyde (MDA) formation in frozen thigh muscles.

This study aimed to determine the effect of the addition of oat hull (0–3%) and high amounts of cereal grains to the diet of broiler chickens in terms of the development of the upper gastrointestinal tract, individual microbial counts in the crop and ileum, and the effect of dietary fibre fractions on microbial changes from the beak to the ileum. In the 28 d trial, 162 one-day-old Hubbard Flex male chickens with an average body weight of 44.5 g were randomly allocated to 27 metabolic cages. The experiment consisted of a randomised, one factorial ANCOVA design composed of a covariate with two ANOVA factorial designs containing nine treatments (3 × 3): three sources of cereal grains (maize, wheat, and barley, with a minimum amount of 500 g · kg⁻¹, each with nine replications) and three levels of oat hull (0, 1, and 3%, each with nine replications). At the end of the study, 81 chickens (9 in each treatment) were slaughtered to determine the weight of the individual organs and characterise the intestinal microbiota. The application of 3% oat hull to the cereal diets increased the weight of the proventriculus and the gizzard (6.3 and 27.3 g, respectively) in comparison to diets without the addition of this structural component (6.0 and 23.7 g). Higher crop counts of total aerobic microbes (6.29 log CFU · g⁻¹) and Lactobacillus spp. (4.05 log CFU · g⁻¹) were observed in diets containing wheat grain compared with maize (4.62 and 3.55 log CFU · g⁻¹, respectively). The main reason for the microorganism’s growth (p < 0.05) was the amount of soluble dietary fibre and hemicelluloses present in the diet: total aerobic microbial count (respectively r = 0.918 and r = 0.816) and Lactobacillus spp. (respectively r = 0.416 and r = 0.442). Barley diets decreased (p < 0.05) E. coli counts in the ileum (2.69 log CFU · g⁻¹) vs. maize and wheat diets (3.41 and 3.45 log CFU · g⁻¹, respectively), mainly due to the increase in the amount of insoluble dietary fibre in the diet (r = −0.462). Reduced total yeast and mould counts in the ileum were also observed (p < 0.05) in connection with the presence of soluble dietary fibre and hemicelluloses in diets (r = −0.397 and −0.398, respectively).

The study aimed to evaluate the influence of solid-state fermentation on the nutritional value and enzymatic activity of rapeseed meal and its effects on the performance of broiler chickens and meat quality, including physicochemical properties (proximate analysis, pH, water holding capacity), antioxidant capabilities, dipeptide composition of the meat and sensory traits. Three dietary treatments were evaluated using broiler chickens: a control without incorporation of rapeseed meal; a second treatment with the incorporation of 3% unfermented rapeseed meal; and a third with the incorporation of 3% rapeseed meal fermented with Bacillus subtilis 67. The study showed that fermented compared to unfermented rapeseed meal was characterized by a significantly higher content of dry matter, crude ash, crude fat and metabolic energy (P < 0.05), and a significantly lower content of crude fiber and glucosinolates (P < 0.05). The B. subtilis 67 strain shows cellulolytic and xylulolytic activity. Fermented rapeseed meal has a positive effect on body weight of birds, daily gain, and European Production Efficiency Factor (P < 0.05). Both rapeseed meal treatments significantly reduced the pH of leg muscles and the water-holding capacity of breast muscles (P < 0.05). The fermented meal had a negative impact on some sensory parameters of poultry meat. There was no significant influence of fermented rapeseed meal on the composition of dipeptides in poultry meat and its antioxidant status.

In the 20 d experiment, the influence of different concentration and supplementation period of commercial blackcurrant extract (BC) in the broiler diets on the oxidative stability of breast and thigh meat, as well as selected performance indices, was investigated. A number of 120 fifteen-d-old Hubbard Flex male chicks (initial BW 363.5 ± 22.9 g) were randomly allocated to five groups: the control and four treatments (6 replicates, 4 birds per cage in each group). The BC extract was administrated to treatment groups at two concentrations (1.25 and 2.5 g/kg) and in different periods within the trial (i.e., from 15 to 35 d and from 25 to 35 d of life). Body weight gain (BWG) and feed conversion ratio (FCR) were determined during the 20-d experiment. At d 35, two randomly selected birds from each cage were decapitated, and pectoral and thigh muscles were collected. Extent of lipid oxidation after storage at chilling (2-3°C, 1, and 5 d) and freezing conditions (after 90 d, −18°C) was determined. The chickens’ growth performance and FCR were not affected by the concentrations and periods of BC supplementation. The enrichment of grower diet with 1.25 g/kg of BC extract reduced the malondialdehyde (MDA) formation in frozen thigh muscles (P<0.05), and this effect tended to appear (P<0.089) irrespective of duration of the supplementation period. Significant extent of lipid oxidation process was found in 1-d-chilled pectoral muscles of chickens receiving BC diet for 20 d or diet containing 2.5 g/kg of the extract. The results showed that BC extract may be an efficient source of antioxidants in chicken diet, which may increase oxidative stability of frozen dark meat. However, the conditions and ability of some polyphenols to initiate oxidation processes have not been fully understood and further studies are required.