ENGLISH VERSION

ZESZYT 370

Katarzyna Ognik
The possibility of using natural antioxidants in feeding of slaughter poultry as inhibitors of lipid peroxidation
zeszyt 370, ss. 147

The tradition of applying natural feed additives, mainly herbs, in poultry feeding has been known for years. However, advance in phytochemistry that enabled the identification of many biologically-active (bioactive) substances caused that in recent years a growing interest has been observed in phytobiotics with antioxidative properties, i.e. in preparations of plant origin, in the aspect of their use in poultry feeding. The interest is chiefly due to the fact that the application of natural antioxidants in poultry assures greater health safety to both animals and consumers of poultry meat.

The aim of this study was to compare antioxidative properties of individual bioactive compounds (RRR-d-alpha-tocopherol, hesperidin, diosmine, quercetin, resveratrol, and Q10 coenzyme) and their mixtures in terms of their potential capability to inhibit the intensity of lipid peroxidation process at the level of feed mixture, blood and muscle tissues of slaughter poultry. An additional assumption of the study was to establish the optimal level of dosage of selected antioxidants to feed mixtures for turkey hens and for broiler chickens that would assure the most effective increase of the antioxidative potential and inhibition of the lipid peroxidation process in feed mixture, blood and tissues of poultry. Additional analyses were carried out to evaluate whether the antioxidants co-acting in the mixture may eliminate causes of oxidative stress induction in the body of birds via their capability to impair the growth of pathogenic and relatively-pathogenic bacteria in feedstuffs.

Three feeding experiments were conducted with Big 6 turkey hens and one experiment was carried out with Ross 308 broiler chickens. Birds were reared under standard zoohygienic conditions, with ad libitum access to drinking water and feed. In each experiment birds from control groups (K 1.0, K 2.0, K 3.0, K 4.0) were fed standard diets, meeting the reqirement of birds for nutrients, that were not supplemented with the experimental additives. In first experiment, 840 turkey hens were divided into 7 groups (K 1.0–G 1.6), 120 birds each (6 replications × 20 birds). The turkey hens from experimental groups were fed diets with 200 g t-1 addition of bioactive compounds, as follows: RRR-d-alpha-tocopherol (G 1.1), hesperidin (G 1.2), diosmine (G 1.3), quercetin (G 1.4), resveratrol (G 1.5), and Q10 coenzyme (G 1.6). In second experiment, 480 turkey hens were divided into 4 groups (K 2.0–G 2.3), 120 birds each (6 replications × 20 birds). The turkey hens from experimental groups were fed diets with 200 g t-1 addition of bioactive compounds, as follows: Q10 coenzyme (G 2.1), and a mixture of bioactive compounds (Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol) in the ratio of 5 : 3 : 2 (G 2.2) and in the ratio of 1 : 1 : 1 (G 2.3). Third experiment with turkey hens (K 3.0–G 3.2) and fourth experiment with broiler chickens (K 4.0–4.2) were conducted in an analogical methodological design, where 360 birds were divided into 3 groups, 120 birds each (6 replications × 20 birds). Turkeys hens and broiler chickens from experimental groups were fed diets with the addition a mixture of bioactive compounds (Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol) in the ratio of 5 : 3 : 2 at the dose of 100 g t-1 (G 3.1 and G 4.1) and at the dose of 200 g t-1 (G 3.1 and G 4.1). Body weight of the birds, feed intake and feed conversion ratio were monitored throughout the study period. Samples of feed mixtures as well as these of blood and muscle tissues of the birds were collected for chemical analyses. In terms of pro-oxidative markers, determinations were carried out for: conjugated dienes (CD), lipid hydroperoxides (HPETE), peroxides (H2O2), malondialdehyde (MDA), and redox potential (ORP). In terms of antioxidative markers, analyses were carried out for: superoxide dismutase (SOD), catalase (CAT), total antioxidative potential (FRAP), glutathione (GSH + GSSG), vitamin E, vitamin C, microelements (Cu, Zn, Fe, Mn, Se), sum of flavonoids and phenolic acids. In terms of lipid markers, analyses were carried out for: total cholesterol (CHOL), LDL and HDL fractions of cholesterol, triacylglycerols (TG), and fatty acids. Once in vivo analyses were completed, a laboratory test (in vitro) was performed to evaluate the effect of the applied 200 g t-1 dose of antioxidants mixture (5 : 3 : 2, Q10 coenzyme + resveratrol + RRR-d-alpha-tocopherol) on the growth of bacteria: Staphylococcus aureus, Salmonella typhimurium, Escherichia coli in the presence of mycotoxins (Aflatoxin B1, Ochratoxin A, and Deoxynivalenol).

Considering all bioactive compounds applied as individual antioxidants added to feed mixtures for poultry, the capability to inhibit the intensity of lipid peroxidation in feed mixtures was displayed only by: Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol. Of all bioactive compounds applied as individual antioxidative additives, the highest capability to stimulate the antioxidative potential at the turkey hens body level was observed for Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol, which was expressed in increased values of FRAP, GSH + GSSG and vitamin E content, and in suppressed activity of SOD in blood plasma. However, the capability to inhibit lipid peroxidation – evaluated mainly based on decreased contents (CD, HPETE, MDA), was expressed only by the additions of Q10 coenzyme and resveratrol. The increase in the markers of antioxidative potential in the breast muscle (GSH and vit. E) and thigh muscle (vit. E) of the birds was stimulated most effectively as a result of the diets supplementation with Q10 coenzyme. Addition of Q10 enzyme, resveratrol and RRR-d-alpha-tocopherol to the diets resulted in reduced levels of ORP, CD, HPETE, and MDA in muscle tissues of the birds. It is worth emphasizing, however, that a significantly better effect of increasing the antioxidative potential and inhibiting the lipid peroxidation process in feed mixtures, as well as blood and muscle tissues of the birds, was recorded upon the coupled use of bioactive compounds, i.e. as a mixture of Q10 coenzyme, resveratrol, RRR-d-alpha-toco-pherol. The conducted experiments indicate also that the mixture of bioactive compounds, i.e. Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol, displayed bactericidal properties against the following strains: Staphylococus aureus, Salmonella typhimurium and Escherichia coli.

The addition of bioactive compounds with antioxidative properties to the diets for turkey hens and broiler chickens had no effect on performance of the birds. It was found that the natural RRR-alpha-d-tocopherol (extract from soybean oil), used in the diets for poultry more effectively stimulates the antioxidant potential and inhibits process of lipid peroxidation in feed mixtures, blood and breast and thigh muscles of birds than widely used racemic acetate dl-alpha-tocopherol. Addition of 200 g t-1 Q10 coenzyme or resveratrol to the diets containing dl-alpha-tocopherol considerably stronger stimulated the antioxidative status and inhibited lipid peroxidation than use only of ethyl dl-alpha-tocopherol. The result of the interaction of natural antioxidants used in the ratio of 5 : 3 : 2 as a mixture of Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol, the effect of stimulation of the antioxidative status correlated with the inhibition of lipid peroxidation process both in feed mixtures, blood of the birds and breast and thigh muscles may be significantly more intensive than upon the use of ethyl dl-alpha-tocopherol with Q10 coenzyme. In order to protect a feed mixture and birds organism at a cellular and tissue level against oxidation may be recommended use of the additive of a mixture of antioxidants: Q10 coenzyme, resveratrol and RRR-d-alpha-tocopherol in a ratio of 5 : 3 : 2  to feed mixtures at a dose of 100 g t-1 for broiler chickens and at a dose of 200 g t-1 for turkey hens. Due to the fact that the combined mixture Q10 coenzyme, resveratrol, and RRR-d-alpha-tocopherol in the ratio 5 : 3 : 2, has antibacterial properties against Salmonella typhimurium, Staphylococus aureus and Escherichia coli, it could be used in the microbiological hygiene of feed at a dose of 200 g t-1. The results of microbiological tests are based only on laboratory tests, and therefore require confirmation and continuation in research carried out in poultry production conditions. The studies performed confirmed the hypothesis about the validity of use of natural origin antioxidants in the diet of slaughter poultry. Natural antioxidant additives can be used in ecological rearing of poultry, where use of synthetic feed additives is prohibited.