Performance of Lambs Fed with Different Oil Sources and Biosurfactant

Diets with a high energy and low fiber content are being employed in lamb feedlotting to optimize performance, and the addition of biosurfactant may make the use of oil feasible as an energy source. Biosurfactant plays an emollient role when used in the diet of monogastric animals and presents possibilities for ruminants. The aim was to evaluate the inclusion or not of biosurfactant in diets with different oil sources (soybean or sunflower) in a high concentrate diet for feedlot lambs and to evaluate animal performance. The experiment was carried out that the Faculty of Zootechnics and Food Engineering of USP, Pirassununga, São Paulo, Brazil. Four diets were evaluated: two oil sources (soybean and sunflower) with the inclusion or not of biosurfactant, with 10 animals per treatment, and without any defined racial pattern. The diet contained 17% crude protein, 78% NDT, 20% FDN, and 5% fat. The initial body weight was 24 kg and the final weight was 42 kg, for a period of 60 days of feedlotting, with individual feeding and weighing every 14 days. A 2 x 2 factorial design was used (soybean or sunflower oil x inclusion or not of biosurfactant), with data analyses using the GLM of SAS, comparing the means using the Student test with a 5% probability. Dry material (DM) consumption was not affected by the diet (P>0.05), with an average intake of 1.44 kg a day, nor was dry material consumption (P>0.05) in relation to live weight, with an average of 4%. The average daily gain (ADG) was greater for the animals that ingested biosurfactant (P=0.0263), with an average of 0.356 kg/day, compared to the animals that did not ingest it, with a weight gain of 0.310 kg/day. The diets with biosurfactant (P=0.0439) presented better dietary conversion, with a average of 4 kg DM.GMP^-1 compared to 4,66 kg DM.GMP^-1 for the diets without the additive, but there was no difference between the oil sources. The CMS values are as expected for live animal weight and as recommended by the NRC (2007). It is concluded that biosurfactant can be an ally when formulating diets with a high level of concentrate and the inclusion of oil, with the different sources studied not affecting performance.