Eva Mrkvicová

Influence of garlic extract on antioxidant status of chicken.

In 2006 the European Union banned the feeding of antibiotic growth promoters because of possible risk of drug resistance in human pathogens bacteria. This is the reason for the study of various phytogenic additives and their extracts as a natural source of biologically important compounds. Antimicrobial substances are a commonly included in chicken feed rations. They are used mainly as prevention against various diseases, and also to stimulate growth. The beneficial effects of garlic on animal organism resulting from their antimicrobial, antioxidative and antihypertensive properities. Studies focused on growth, conversion and meat quality of different types of animals indicate its positive effects. In our experiment we studied the influence of garlic extract in a dose of 0, 10 g and 15 g per 1 kg of chicken feed mixture. We focused on weight gains and antioxidant status of an organism. The experiment took 39 days. 54 seven-day-old chickens were included in the experiment. The chickens were weighed once a week, when aged 11, 17, 24, 31 and 38 days, at the same time of the day. The chickens had ad libitum access to feed ration and water. The chickens were taken blood sample at the end of the experiment when 39 days old. Their antioxidant status were measured using ABTS, FRAP and DPPH methods. Our results show that owing to higher concentration of garlic extract in feed ration the antioxidant status of observed chickens was increased. DPPH method showed an increase in antioxidant status of both experimental groups by 38% (a group with a dose of 10 g/kg of mixture) and by 46% (a group with a dose of 15 g/kg of mixture) compared to the control group. When using FRAP method, antioxidant status of both G10 and G15 groups increased by 24%, resp. 16%. No evidential differences in antioxidant activity between the experimental groups and control group were found using ABTS method. The supplement of garlic extract into a feed ration did not have any influence on weight gains of chickens.

The effect of feeding milk thistle seed cakes on quality indicators of broiler chickens meat

This study was conducted to evaluate the effect of feeding milk thistle (Silybum marianum L.) seed cakes at dose 5% and 15% in feed mixture on quality indicators of broiler chickens meat. The used milk thistle seed cakes contained 3.73% of flavonolignans and 129.83 mg.kg-1 of cyanidin-3-glucoside. A 150 cockerels of Ross 308 were divided into three equal groups. The chickens were fattened on conventional deep litter system. The experimental groups received feed mixtures containing 5% of milk thistle seed cakes (MT5), 15% of milk thistle seed cakes (MT15) and third group was control - without milk thistle seed cakes (C). The trial lasted 37 days. At the end of trial was observed significant higher average weight of chickens (2,320.31 g) in control group. Compare to that the experimental group MT5 achieved significant lower mean bodyweight 2,166.69 g. From the perspective of fattening was decreased growth of chickens where a higher percentage of milk thistle seed cakes (MT15). The group MT15 was up to 420 g lower slaughter weight compared to the control group. This was probably due to the higher content of fiber in the feed. At the end of experiment 15 birds were selected randomly from each group, weighed and slaughtered. Feathers were removed and chickens were eviscerated. Carcass yield was calculated for each group like as percentage of live weight. The MT5 and MT15 group had significantly higher breast meat tenderness that the control group. Initial pH1 was highest in group with its middle addition of milk thistle seed cakes (MT5). Significant differences were not observed between control and group MT15. Breast meat was rated as the best in parameter flavour in control and MT15 group. The thigh meat was evaluated significantly best for colour parameter in MT15 group. Fibreness was rated as the finest in MT15 group. The addition of milk thistle seed cakes do not worsened sensory characteristic of breast or thigh meat of broilers and reflects optimal sensory quality traits.

The effect of feeding wheat varieties with different grain pigmentation on growth performance, texture, colour and meat sensory traits of broiler chickens

The feeding effect of of three spring wheat genotypes (Vanek, Konini and UC66049) with different grain colour on growth performance, body composition and meat quality parameters of broiler chickens was tested. Ninety chickens were divided into three groups (control, Konini and UC) with 30 chickens in each. The tested genotypes were compares with standard variety Vanek (control) with common (red) grain colour. The two experimental groups received feed mixtures containing 38.2% of wheats with different grain colour: groups Konini (n = 30) and UC (n = 30) with. The third group (n = 30) had 38.2% of common wheat Vanek cultivar (Control group). The live weight of chickens between the experimental groups and control group was not significant different, as well as body composition and chemical analysis of breast and thigh meat of chickens. The feeding of wheat with different grain colour had no effect on performance parameters of broiler chickens. Breast meat tenderness according to the Razor Blade Shear Force was higher in control group against experimental groups. The colour change was not significantly different in all coordinates. pH values (measured after 1-hour post mortem) were found significantly higher in the group fattening with Konini wheat than control and UC groups. Chickens meat from the experimental group was characterised by steady overall quality. The effect of various feeding had no effect on meat quality in terms of relevance to consumers.