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 (Vánek, 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 Vánek (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 Vánek 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.


INTRODUCTION
The large scale of phenolic compounds in wheat grain contains simple molecules such as phenolic acids to highly polymerised compounds such as tannins and proanthocyanidins (Yang et al., 2009).The polyphenols possess a number of beneficial properties and its antioxidant effect is very important.The antioxidant compounds have already been identified as phenolic acids, derivatives of stilbene, flavan-3-ols (catechin and epicatechin), flavonols and anthocyanidins (Caillet et al., 2006).Positive effects of phenolic compounds used in small doses in animal diet observed which can act as health promoters rather than inhibitors (Starčević et al., 2015).
The purple colour of wheat grains is caused by anthocyanins accumulated in the pericarp, while the blue colour is generated by anthocyanins in the aleurone layer of the endosperm (Zeven, 1991).Anthocyanins are the largest group of water soluble natural pigments that give red, violet, and blue colour to many fruits, vegetables and also in cereal grains.Anthocyanins have some beneficial health effects concerning oxidative damage, detoxification enzymes, and the immune system (Choia et al., 2007;Prior and Wu, 2006).
The broiler chickens are the most popular among poultry species in the world, because of the simplicity of cooking.The chicken meat is considered to be a healthy food due to its relatively low fat, saturated fatty acid and cholesterol content

Volume 11 146
No. 1/2017 The effect of feeding wheat varieties with different grain colour on growth performance, texture, colour, and sensory traits of broiler chicken's meat was evaluated.

MATERIAL AND METHODOLOGY Animals, nutrition and growth performance
The animal procedures were reviewed and approved by the Animal Care Committee of the Mendel University in Brno.The experiment was performed with 90 cockerels of Ross 308 hybrid.The conventional deep litter system with wood shavings was used.The trial was performed from day 12 to day 37 of chickens age.Room temperature and humidity were controlled according to requirement for actual age of chickens in Aviagen Group (2014).Lighting system was 16 hours light and 8 hours dark.Cockerels were divided into three equal groups.The two experimental groups received feed mixtures containing 38.2% of wheats with different grain colour: groups Konini (n = 30) with Konini wheat cultivar and UC (n = 30) with UC66049 cultivar, respectively.The third group (n = 30) had 38.2% of common wheat Vánek cultivar (C).The rations were calculated according to the "Recommended nutrient content in poultry diets and nutritive value of feeds for poultry" (Zelenka et al., 2007).
The basic chemical composition of used experimental wheats is presented in Table 1.
The composition and nutrient content of diets are shown in Table 2 and Table 3, respectively.
The chickens were fed ad-libitum.Health status was evaluated daily and live weight measured every week during the trial.
At the end of the experiment fifteen birds were selected randomly from each group, weighed and slaughtered by decapitation.Feathers were removed and chickens were eviscerated.Carcass yield was calculated.Breast and thigh meats without skin were separated from carcasses after cooling.All visible external fat was removed from sample meats.The breast and thigh meat was weighed and their percentage of live body weight was calculated.

Sensory analysis
Sensory analyses of breast and thigh meat samples were evaluated by 10 panellists in special sensory laboratory (Department of Food Technology, Mendel University) according ISO 8589.Each sample (breast and thigh) was packed into plastic case and frozen (-18 °C).These samples were thawed (cold storage room, 4 °C) and boiled in convection oven (200 °C, 60% humidity, 1 hour).Professional evaluation group was represented by a panel of trained panellists under ISO 8586-1.We used a graphic non-structured scale (100 mm) to compare experimental group of descriptors (odour, colour, fibriness, chewiness, juiciness, flavour, fatty taste) with control group.

Statistical analysis
Data were processed by Microsoft Excel (USA) and Statistica version 12.0 (CZ).One-way analysis (ANOVA) was used.To ensure evidential differences Scheffe´s test was applied and p <0.05 was regarded as statistically significant difference. Experiments

Grow performance and body composition
The mean live weight of chickens was not different among groups at the end of experiment (Table 4).The differences between the experimental groups and control group was not significant (p >0.05).Also, it was found feed conversion ratio (FCR) in amount 1.68 kg.kg -1 , 2.00 kg.kg -1 and 1.76 kg.kg -1 per group for Vánek, Konini and UC, respectively.Our findings confirm studies of   2010) observed in their experiment with wheat with purple colour of grain higher average live weight of laying hens for experimental group.Hens in the experimental group laid larger eggs in comparison with control group and the colour of yolk was not influenced by purple wheat feeding.
The Table 5 showed percentage of body composition of chickens.There were non-significant (p >0.05) differences in carcass yield.
The chemical analyses of breast and thigh meats are shown in Table 6.Differences between groups are not significant (p >0.05).

Texture, colour and of meat
The Razor Blade Shear Force results (n = 30) are presented in Table 7.There were significantly (p <0.05) higher breast meat tenderness in control group against Konini and UC group.
The colour change is not significant in all parameters (lightness L*, a* and b*) as it is shown in Table 7.There were found no significant differences (p >0.05) among all three groups.The total colour change (∆E*ab from 1.11 to 2.67) is clearly perceptible but not yet discordant and it is acceptable for consumers (Saláková, 2012).
The pH values from control and both experimental groups are shown in Table 7.Initial pH1 was not significant (p >0.05) in all three group.pH2 values were measured after 1-hour post mortem.The significantly higher (p <0.05) pH2 value was in the Konini group in comparison with Vánek and UC groups.Differences were not observed between Vánek and UC groups.
There are no published studies on the effect of feeding wheat varieties with different grain pigmentation on

Sensory analysis
The significantly (p <0.05) more intense odour of breast meat was found in the Konini group against control group.Significantly better chewiness of breast meat was in Konini than control group confirms the results of the Razor Shear Force and Razor Shear Energy.
According to sensory analysis thigh meat had significantly (p <0.05) more intense colour in experimental groups.The control group had significantly lowest rating for this parameter.The Konini group was significantly (p <0.05) more evaluated for thigh meat fibriness parameter compared to control.The thigh meat was significantly (p <0.05) better for chewiness parameter in Konini group versus control group, like as the breast meat.

CONCLUSION
The feeding of wheat with different grain colour had no effect on performance parameters of broiler chickens.The chemical composition of breast and thigh meat was balanced among all three groups.The higher breast meat tenderness was found in control group than in experimental groups according to the Razor Blade Shear Force results.The color change did not significantly differ in all coordinates.In the pH2 (measured after 1-hour post mortem) there was found significantly higher (p <0.05) value in the Konini group than C and UC groups.The effect of various feeding had no effect on meat quality in terms of relevance to consumers.

(
Haščík et al., 2016; Starčević et al., 2015).The nutritional properties of poultry meat are highly valued (Starčević et al., 2015).The development of the food industry leads to the search for new raw materials with improved nutritional properties.The coloured grains of some cereals have potential in production of functional food with added health benefits (Li et al., 2004; Garg et al., 2016).Testing of influence of different grain colour has been going for several years and the results have been published continuously (Karasek et al., 2014; Stastnik et al., 2014; Mareš et al., 2015; Mrkvicová et al., 2016).

Table 1
Chemical composition of used experimental wheats in dry matter.

Table 3
Nutrients content of diets in dry matter.The tenderness of the fillets was determined through the application of the Meullenet-Owens razor shear (MORS) test, using a texture analyser (Model TA-XT2Plus, Texture Technologies, Scarsdale, N.Y., U.S.A.) as described by Meullenet

et al. (2004) and Cavitt et al. (2005) during
which Razor Blade Shear Force (N) and Razor Shear Energy (N.mm -1 ) were recorded.Tests using the MORS blade are conducted on whole intact right fillets with 5 replicates.The sharp blade was replaced every 80 measurements for optimum shearing performance.Test Settings: test speed 10 mm.s -1 and distance 20 mm.Colour measurement was performed by CIE L*a*b* colour space.L* (lightness), a* (redness) and b* (yellowness) values from the breast meat sample surface on the dorsal side were measured using a Spectrophotometer CM-3500d (Konica Minolta Sensing Inc., Japan) in SCE mode (specular component excluded), angle 8 °, 8 mm slot.Each sample was measured at three places 1-hour post-mortem.Average value was taken as the final result.∆E*ab (CIE, 2007) was calculated according next formulas (

Table 4
Live weight (g) of broilers at 37 th day of age.

Table 6
Chemical analysis of breast and thigh meat (%) of broilers chickens.Differences between the groups are not significant (p >0.05).No.1/2017 pomace containing polyphenols.These diets had no effect on the growth of broiler chickens.On the other hand, Ruckschloss et al.(

Table 7
Effect of feeding wheat varieties with different grain pigmentation on texture, pH and colour of breast meat (means ±standard error).Note: pH1 values were measured just after slaughter in breast, likewise pH2 values were measured after 1-hour post mortem.∆E*ab is compared with control group.a,b Means in a row within effect with no common superscript differ significantly (p ˂0.05).

Table 8
Sensory analysis of breast meat of chickens (mm in 100 mm scale).