No abstract

The cysteine protease inhibitor cystatin was purified from chicken egg white and its antimicrobial activity determined for a series of pathogenic bacteria. The results indicate that Acinetobacter lwoffii, Escherichia coli, Oligella sp. and Pseudomonas aeruginosa are highly sensitive to low concentrations of cystatin, which possesses bactericidal activity. No inhibition was observed with a Citrobacter freundii strain. Fifty percent growth inhibition (IC 50 ) was observed at cystatin concentrations in the range of 80 and 100 lg/ml, and the growth was completely inhibited at concentrations in the range of 100 and 200 lg/ml. Fifty percent growth inhibition (IC 50 ) for Staphylococcus aureus, Staphylococcus gallinarum, and Staphylococcus xylosus strains was observed at 150 and 200 lg of cystatin/ml respectively, and growth was completely inhibited at cystatin concentrations in the range of 300 and 1000 lg/ml. The activity of cysteine proteases was significantly decreased in the culture supernatant of microorganisms when chicken cystatin was added. In this study, we observed that chicken cystatin may be a candidate for antibacterial drug development aiming at controlling bacterial pathogens including Escherichia coli, Pseudomonas aeruginosa, and another possible application might be as a therapeutic agent for health improvement.

Carnosine is a dipeptide formed from the amino acids β-alanine and histidine and found in large amounts in the brain and muscle, especially fast twitch muscle. Carnosine has an antioxidant role and accounts for about 10% of the muscle's ability to buffer the H+ ions produced by high intensity exercise. Due to the interesting role of carnosine, the aim of the study was observe the effects of carnosine intake on pro-antioxidant status in highly trained athletes exposed to intense exercise.Fourteen male athletes from the Polish national kayak and canoe teams participated in placebo-controlled and cross-over study. The athletes were supplemented with 4 g/d carnosine for 14 days. Blood samples were collected before and 30 min, 24 h and 48 h after 2000 m exercise trial. In blood, hydrogen peroxide (H2O2), nitric oxide (NO), markers of RO/NS activity 8-isoprostanes and 3-nitrotyrosine, total (GSHt) and oxidised glutathione (GSSG), antioxidant status (APO) and superoxide dismutase (SOD) were determined. There were not observed statistically significant differences in exercise-induced changes in H2O2 and NO concentrations and SOD activity after carnosine intake. However, carnosine prevented an increase in 8-isoprostanes, 3-nitrotyrosine and GSSG concentrations as well as elevated redox status (GSHt-2GSSG)/GSSG at post-exercise period.Although, oral supplementation with 4 g carnosine did not affect RO/NS generation, it significantly attenuated exercise-induced glutathione loss, reduced oxidation/nitration markers concentration and SOD activity. These results suggest that carnosine could provide antioxidative protection for highly trained athletes.

The objective of the study was to test the effect of diets supplemented with β-alanine, L-histidine, and carnosine on the histidine dipeptide content and the antioxidative status of chicken breast muscles and blood. One-day-old Hubbard Flex male chickens were assigned to five treatments: control diet (C) and control diet supplemented with 0.18% L-histidine (ExpH), 0.3% β-alanine (ExpA), a mix of L-histidine\β-alanine (ExpH+A), and 0.27% carnosine (ExpCar). After 28 days, chicken breast muscles and blood samples were analyzed for the antioxidant enzyme activity (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)), carnosine and anserine content, amino acid profile, and anti-radical activity (ABTS, DPPH, ferric reducing antioxidant power (FRAP)). The results of the study showed that carnosine supplementation effectively increased body weight and breast muscle share in chicken carcasses. Carnosine and L-histidine supplementation with or without β-alanine increased carnosine content in chicken breast muscles up to 20% (p = 0.003), but the boost seems to be too low to affect the potential antioxidant capacity and amino acid content. The β-alanine-enriched diet lowered dipeptide concentration in chicken blood serum (p = 0.002) and activated catalase in chicken breast muscles in relation to the control group (p = 0.003). It can be concluded that histidine or dipeptide supplementation of chicken diets differently affected the total antioxidant potential: in breast muscles, it increased dipeptide content, while in blood cell sediment (rich in erythrocytes), increased SOD and GPx activities were observed.

There is an increasing demand for cost-effective and ecologically-friendly methods for valorization of poultry feather waste, in which keratinolytic bacteria present a great potential. Feather-degrading bacteria were isolated from living poultry and a single strain, identified as Kocuria rhizophila p3-3, exhibited significant keratinolytic properties. The bacterial strain effectively degraded up to 52% of chicken feathers during 4 days of culture at 25 °C. Zymographic analysis revealed the presence of two dominating proteolytic enzymes in the culture fluid. Culture conditions were optimized in order to maximize the liberation of soluble proteins and free amino acids. A two-step procedure was used, comprising a Plackett–Burman screening design, followed by a Box–Behnken design. Concentration of feather substrate, MgSO4 and KH2PO4 were the most influential parameters for the accumulation of soluble proteins in culture K. rhizophila p3-3, while feathers and MgSO4 also affected the concentration of amino acids. The resultant raw hydrolysate supernatant, prior to and after additional treatments, was rich in phenylalanine, histidine, arginine and aspartic acid. Additionally the hydrolysate exhibited radical-scavenging activity and ferric reducing power.Electronic supplementary materialThe online version of this article (10.1186/s13568-018-0538-y) contains supplementary material, which is available to authorized users.

1. The objective of this study was to investigate how a diet containing spray-dried blood cells (SDBC) (4%) with or without zinc (Zn) would affect the concentration of two histidine heterodipeptides and the antioxidant status of broiler blood and breast muscles. 2. The study was carried out on 920 male Flex chickens randomly assigned to 4 dietary treatments: I - control, II - diet I with SDBC, III - diet I with SDBC and supplemented with Zn and IV - diet I supplemented with L-histidine. Birds were raised on floor littered with wood shavings, given free access to water and fed ad libitum. Performance indices were measured on d 1, 21 and 42. 3. The activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase was analysed in plasma, erythrocytes and muscle tissue. The total antioxidant capacity of plasma and breast muscles was measured by 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, as well as by ferric reducing antioxidant power (FRAP). Carnosine/anserine content of meat and plasma were determined using HPLC. Diets and breast muscles were analysed for amino acid profile and selected microelement content. 4. Histidine supplementation of the diet increased glutathione peroxidase activity in plasma and superoxide dismutase activity in erythrocytes. Moreover, the addition of SDBC or pure histidine in the diet increased histidine dipeptide content and activated enzymatic and non-enzymatic antioxidant systems in chicken blood and muscles. However, it led to lower growth performance indices. 5. The enrichment of broiler diets with Zn increased the antioxidant potential and the activity of superoxide dismutase in plasma, which was independent of the histidine dipeptide concentration. Zn supplementation combined with SDBC in a broiler diet led to the increase of superoxide dismutase and glutathione peroxidase activity, but it did not affect the radical-scavenging or ferric iron reduction abilities of muscles.

The aim of this study was to evaluate the effect of the baical skullcap root (<I>Scutellaria baicalensis radix</I>) on the performance, chemical composition of the muscles and sensory characteristics of the meat of broiler chickens. 120 one-day old Hubbard Hi-Y broiler hybrids were assigned to four groups of 30 each and fed either a basal diet (control) or a basal diet supplemented with 0.5%, 1.0% or 1.5% ground root of skullcap. The body weight, weight gain, feed consumption and feed : gain ratio were calculated after 42 days. The addition of the ground baical skullcap root to the fodder had no effect on the quality or chemical composition of the breast and leg muscles of the broiler chickens. However, it positively influenced some of the performance characteristics of the chickens.

The objective of this study was to investigate the effects of 1) spray dried blood cells rich in histidine and 2) pure histidine added to feed on the antioxidant status and concentration of carnosine related components in the blood and breast meat of female turkeys. The experiment was performed on 168 Big7 turkey females randomly assigned to 3 dietary treatments: control; control with the addition of 0.18% L-histidine (His); and control with the addition of spray dried blood cells (SDBC). Birds were raised for 103 d on a floor with sawdust litter, with drinking water and feed ad libitum. The antioxidant status of blood plasma and breast muscle was analyzed by ferric reducing ability (FRAP) and by 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging ability. The activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was analyzed in the blood and breast meat, with the content of carnosine and anserine quantified by HPLC. Proximate analysis as well as amino acid profiling were carried out for the feed and breast muscles. Growth performance parameters also were calculated. Histidine supplementation of the turkey diet resulted in increased DPPH radical scavenging capacity in the breast muscles and blood, but did not result in higher histidine dipeptide concentrations. The enzymatic antioxidant system of turkey blood was affected by the diet with SDBC. In the plasma, the SDBC addition increased both SOD and GPx activity, and decreased GPx activity in the erythrocytes. Feeding turkeys with an SDBC containing diet increased BW and the content of isoleucine and valine in breast muscles.