Abstract #T464

# T464
Effect of lipid sources with different fatty acid profiles on intake and nutrient digestion of feedlot Nellore steers.
Juliana Duarte Messana*1, Giovani Fiorentini1, Isabela P. C. Carvalho1, Pablo S. Castagnino1, Telma T. Berchielli1, 1UNESP - Univ. Estadual Paulista, Jaboticabal, São Paulo, Brazil.

The present study was conducted to determine the effect of lipid sources with different fatty acid profiles on intake and nutrient digestion. Ten rumen and duodenal fistulated Nellore steers (268 body weight ± 27 kg) were distributed in a double 5 × 5 Latin square (5 periods of 20 d, including 15 d for diet adjustment and 5 d for sample collection). Dietary treatments were: without fat (WF), palm oil (PO), linseed oil (LO), protected fat (PF; Lactoplus), and whole soybeans (WS). The roughage feed was corn silage (600 g/kg on a DM basis) plus concentrate (400 g/kg on a DM basis). Throughout the entire experimental period, the allowance was adjusted to allow refusals of approximately 100 g/kg in relation to the total amount consumed on the previous day. Feed refusals were collected and weighed before feeding for the first 5 d of each experimental period. Feces were collected for 5 d to estimate the digestibility of dietary constituents. Data were analyzed using the PROC MIXED of SAS. The higher intake (P < 0.001) of DM, OM was found in animals on the diet with PF and WF. Animals fed with WS had intermediate intake, whereas the diet PO had the lowest intake. The intake of DM and OM of animals fed with LO did not differ from PO and WS diets. The higher EE intake (P < 0.001) occurred in animals receiving PF. However, animals fed PO, showed intake similar to that of animals fed WF. There were no differences for the NDF intake (P > 0.05). The treatments with PO and LO decreased total digestibility of DM (P = 0.021), OM (P = 0.048) and EE (P < 0.001). Animals fed with the WF diet had lower (P < 0.001) EE digestibility than other diets. The addition of LO resulted in the lowest NDF digestibility (P = 0.047; 0.40 kg/kg), and the NDF digestibility was not different among the other diets. These observations may be linked to the number of double bonds in the fatty acid molecules and to the high availability of this source (LO), which tends to reduce cellulolytic bacteria proportion. Diets with lipid sources with different fatty acid profiles affected intake and nutrient digestion.

Key Words: beef cattle, lipid, metabolism ruminant