The effect of feeding triticale and rape seed products on sensory characteristics of broiler meat

The experiment was with 117 broiler chickens divided into five groups: control (soyabean oilmeal as protein feed) and four experimental fed on varied rations of triticale, rapeseed oilmeal and ground rape seed. The chickens were slaughtered at the age of 8 weeks. The carcasses were processed and stored for six months at — 18°C. Sensory examination was carried out on boiled breast and leg muscles. Diets containing 50% triticale and up to 18% rapeseed oilmeal or 12% of rape seeds did not negatively affect either palatability or flavour of breast meat and boullions. The flavour of leg muscles was affected negatively when chickens were fed on a 50% triticale and 12% rape seeds diet.


INTRODUCTION
Triticale and rapeseed oilmeal have become popular in Poland as soya and maize substitutes in broiler feeding (Rutkowski i Gawęcki, 1988a, b).However, some observations have indicated that these feeds negatively affect the palatabili ty and flavour of the meat (Shingari et al., 1976;Tilgner, 1957;Uziębło et al., 1987 a, b;1988).
Since the dietary contents of triticale and rapeseed meal used in the reported experiments were relatively high, it seemed interesting to evaluate the effect of these components at two levels of inclusion and to compare diets containing rapeseed oilmeal and whole ground rape seeds.

MATERIAŁ AND METHODS
One hundred and seventeen chickens were randomly divided into control (No. 1-24) and four experimental groups as follows:    rapeseed oilmeal and ground rape seeds in the diets (Table 1).The broilers were slaughtered at the age of 8 weeks and the carcasses were processed according to the technology used by the meat industry in Poland.After cooling, the carcasses were packed into plastic bags and stored for six months at -18°C.Sensory analysis was carried out individually on boiled breast and leg muscles.The meat and bouillons were tested after Baryłko-Pikielna's (1975) and Tilgner's (1957) sensory methods by a panel of 5 persons of proven sensory abilities (Polish Standard -65/A).The meat test included: colour, structure, flavour (intensity and appetite augmentation ąuality), palatability, tenderness and juiciness.Bouillons were evaluated according to their colour, clarity, flavour and palatability.
Every sample and characteristic was assessed independently and graded using a 5 degree scoring system (5 -the best).The results were analysed using simple analysis of variance (Ruszczyć. 1970).

RESULTS
The results are summarized in Table 2.No statistically significant differences between the groups were found for each chracteristic of breast muscles, while in leg muscles the flavour desirabihty in birds fed a higher level of triticale and rape seed grain (group No. 5) was significantly lower than in control chickens and in birds fed lower levels of these feeds (groups No. 1 and 3, respectively).However, when all eight traits were taken into account, a smali but distinct tendency for higher scores of both breast and leg muscles of chickens fed on rapeseed (group No. 3) than of birds fed rapeseed oilmeal (group No. 2) was observed.Only the intensity and desirabihty of the flavour of breast muscles were scored slightly lower in birds fed on rape seed than on rapeseed meal.The leg muscles of chicken given diet No. 3 with a lower level of triticale and rapeseed scored the highest number of grades 4 for flavour desirability (Table 3).Sensory evaluation of bouillons prepared from breast and leg muscles did not reveal any significant effect of the diets (Table 4).

DISCUSSION
The observations of some workers on the unfavourable influence of triticale and rape seed products on the ąuality of broiler meat was not confirmed in this experiment.Only in the chickens fed the higher łevel of triticale and rapeseed did the leg muscles have a significantly less acceptable flavour than from the control birds and chickens fed a lower level of triticale.Feeding full-fat rape seed affects the fat content and fatty acid composition of broilers (Smulikowska et al. 1990).This may explain the slight generał tendency for higher meat quality, except flavour, in birds fed on rapeseed than on rapeseed oilmeal.The lower scoring of flavour of leg muscles in chicken fed on the higher triticale and fuli fat rape seed diet may indicate that some autooxidation of fat could take place during a long period of storage.Fat oxidation results in an undesirable flavour and sensory changes in meat (Działoszyński, 1958).
A dietary level of 12 per cent of rape seed is probably close to the upper acceptable level.

CONCLUSIONS
Diets containing 50% triticale an up to 18% of ground rapeseed oilmeal or 12% of rape seeds did not negatively affect either palatability or flavour of breast meat and bouillons evaluated after 6 months of storage at -18°C.The flavour of leg muscles was affected negatively when chickens were fed on a 50% triticale and 12% rape seed diet.
birds.They received different amounts of triticale, Components and chemical composition of feed mixtures,