TDK conference 2016

Broiler chickens play remarkable role in food production; therefore, investigations on the effect of different nutritional factors on carcass composition are of great importance. Possible influence of dietary cereal type, dietary crude protein content and butyrate supplementation on meat quality is not yet fully elucidated; hence we aimed to assess these factors in our study.

In the experiment, Ross 308 broiler chickens were obtained and allocated to eight groups (n=10/group). Four of them were fed with wheat-based diet, rich in soluble non-starch polysaccharide (NSP), while the others were reared on maize-based diet, representing lower NSP level. Crude protein content of the diets was set to the requirements of the appropriate dietary phase (normal protein = NP) or reduced by 15% in certain experimental groups (low protein = LP). Feed of animals was formulated with the application of sodium (n-)butyrate or without it in the control groups. On week 6 live weight, and following slaughtering carcass weight as well as weights of pectoral muscle, thighs, liver, heart, spleen and abdominal fat were measured. Further, chemical analysis of pectoral and femoral muscle was carried out. Effects of wheat-based dietary groups compared to maize-based diet, and differences between NP and LP as well as between control and butyrate-supplemented groups were studied by multi-way ANOVA.

Live weight was significantly elevated by LP diet and butyrate supplementation. Relative weight of pectoral muscle increased in LP groups; however, relative liver weight was decreased by wheat-based diet and increased by butyrate application. The relative mass of heart and spleen diminished, while that of abdominal fat increased in groups fed diets with lowered crude protein level. Protein content of pectoral muscle was reduced by wheat-based diet, further, the same parameter of femoral muscle diminished and fat content elevated in LP groups. Butyrate supplementation decreased the protein content and increased the fat content of femoral muscle.

According to our results, the investigated factors significantly influenced carcass composition of broiler chickens. Chemical composition of pectoral and femoral muscle changed differently in case of various nutritional factors, which might be in connection with the distinct metabolism of the two muscles. Increasing effect of butyrate supplementation on the fat content of thighs may contribute to improve meat quality; therefore it can be advantageous from food quality point of view. Literature data indicated that reduced crude protein content of diet decreased nitrogen excretion, however, according to our results, increased the abdominal fat mass. Determination of optimal protein content of feed should happen by taking these two facts into consideration.