Tobacco cv. Solaris seed cake in the diet of growing beef calves

After cold oil extraction from Nicotiana tabacum L. cv. Solaris (PCT/IB/2007/053412) seeds, the co-product Solaris seed cake (CP 34.7 g/100 g DM) was tested as a possible alternative protein source in beef cattle diet. Ten male crossbred Friesian growing beef calves raised in a commercial farm located in Benevento province, average weight 157.9 (±24.5, SEM) kg and average age 228.5 (±71.9) days, were divided in two homogeneous groups, Solaris (SOL) and Control (CTR). According to the nutritional needs of the selected animals, two isoenergetic and isonitrogenous diets were formulated. Groups were daily fed 21 kg of legume and grass haylage, ad libitum mature grass hay and concentrates mixture made by 40% of corn, 40% of barley, 10% of commercial feed and 10% of Solaris seed cake, and by 40% of corn, 40% of barley, 20% of commercial feed, respectively for SOL and CTR group. The trial lasted 66 days, including 16 days of adaptation to the experimental diets. Group feed intake (offered-refusal) was monitored weekly, individual body weight (BW) was recorded at 0- and 66-days, and body condition (BCS) of animals was scored at 0-, 34- and 66 days. Average daily gain (ADG) was calculated. Feeds offered and left over were weekly sampled and chemical composition was analysed according to official methods. The effect of the dietary treatment on individual BW, BCS and ADG was processed by analysis of the variance also considering the covariate effect at 0 days (GLM, ANCOVA; SPSS Inc., Chicago, IL, USA). Significance was declared at p < 0.05. The daily group intake of concentrate was in average 35.4 (±1.21) kg DM and 36.5 (±1.31) kg DM for CTR and SOL group respectively, indicating the palatability of Solaris seed cake. The dietary treatment did not affect (p > 0.05) individual BW (207.7 kg vs. 215.9 ± 9.8 kg, respectively for CTR and SOL), ADG (0.86 kg/d vs.1.05 kg/d ±0.15, respectively for CTR and SOL), and BCS (3.31 vs. 3.41 ± 0.16, respectively for CTR and SOL). Although not conclusive, results suggest that the innovative Solaris seed cake represents a promising alternative ingredient in growing calves’ diet. This co-product from the innovative energy crop may contribute to the reduction of feeding costs in beef farming and could represent a great opportunity for re-designing the tobacco cultivation, especially in inner Mediterranean areas. Acknowledgements The research was funded by AGRIFOOD, PON MISE.