Effects of dietary soyabean, rapeseed and linseed oils on performance, slaughter yield and fatty acid profile of breast meat in turkeys

The objective of this study was to determine the physiological effect of supplementing turkey diets with different vegetable oils, i.e. soyabean (S) oil, rapeseed (R) oil and linseed (L) oil, which have different concentrations of polyunsaturated fatty acids (PUPA). The total contents of n-6 PUFA and n-3 PUPA were as follows: diet S, 49.7 and 7.02%, diet R, 33.0 and 7.96%, and diet L, 30.3 and 30.6%; the n-6/n-3 PUFA ratio was 7.3, 4.4 and 1.0, respectively. The experimental materials comprised four groups of turkey hens (14 replications of fifteen birds each). The amount of dietary oil supplementation was increased from 2% in the first four weeks to 6% at the final stage of fattening (14-15 weeks). The apparent total tract digestibility of crude fat in 7-week-old turkeys (2.5% oil in diet) ranged from 89.9 to 91.1%, and showed no statistically significant differences. Dressing percentage, breast, thigh, and drumstick muscle contents did not differ among groups. Group L had a significantly higher intestinal fat weight (0.84% body weight (BW)) than the other groups (0.60-0.62%). In comparison with diet S, diets R and L contributed to a significant decrease in the levels of saturated fatty acids (from 32.9% to 30.3 and 30.2%) in breast meat lipids. In group L turkeys, the share of PUFA in total fatty acids in breast meat lipids was significantly higher (37.3% vs 29.4 and 27.1% in groups S and R, respectively), and the n-6/n-3 PUFA ratio was significantly lower (1.2 vs 5.6 and 5.1). As for the performance indices (final BW, feed conversion ratio), both rapeseed and linseed oils could be recognized as comparable alternatives to soyabeen oil (in both cases P>0.05 vs S group). However, the highest final BW followed the dietary treatment with linseed oil (P<0.05 vs group R).