The effect of dietary high-tannin and low-tannin faba bean (Vicia faba L.) on the growth performance, carcass traits and breast meat characteristics of finisher turkeys

This study evaluated the effects of dietary replacement of soybean meal (SBM) with faba beans (FB) seeds with a different content of condensed tannins on growth performance and carcass traits and breast meat characteristics in finisher turkeys (13-18 weeks of age). Male Hybrid Converter turkeys were divided into 7 groups corresponding to 7 different finisher diets: a control diet, which contained SBM, and experimental diets where SBM was replaced with 100, 200 and 300 g/kg of high-tannin (HT) or low-tannin (LT) faba beans. Condensed tannin content was 10-fold higher in HT faba beans than in the LT variety (7.84 vs 0.76 mg/g DM, respectively). Regardless of FB variety, dietary inclusion of FB up to 300 g/kg instead of SBM had no adverse effects on the productive parameters or carcass traits of finisher turkeys. The replacement of SBM meal with FB as the dietary protein source had no influence on the proximate chemical composition, physicochemical properties or sensory attributes of turkey meat. In comparison with HT faba beans, LT faba beans did not affect feed intake, body weight gain or the mortality rates of finisher turkeys, but they significantly (P = 0.014) improved the feed conversion ratio. The breast meat of turkeys fed diets supplemented with HT faba beans was darker (P = 0.012), with a lower contribution of yellowness (P = 0.010), and it had a lower content of dry matter (P = 0.036) and ash (P < 0.001) than the meat of turkeys fed diets containing LT faba beans. Diets with HT and LT faba beans changed the proportions of only a few fatty acids (FA) in turkey meat, but the health related lipid indices of meat, such as the concentrations of n-6 PUFAs, n-3 PUFAs and the n-6/n-3 PUFA ratio, were not influenced by the alternative protein source and the faba bean variety. In conclusion, both LT and HT faba beans (containing 0.76 and 7.84 g/kg of tannins, respectively) can be added to turkey finisher diets at up to 300 g/kg as an effective substitute for SBM without compromising the key variables of performance and with no negative effects on carcass traits and breast meat quality parameters.