Authors : T.S. Vafa, A.A. Naserian, A.R. Heravi Moussavi, R. Valizadeh and M. Danesh Mesgaran
Abstract: Two experiments were designated to examine the effects of different levels of fish oil and canola oil on in vitro and in vivo nutrient digestibility. Experiment 1 was performed to assess the effects of unsaturated oils (fish oil, canola oil, their combination) in three levels (2, 4 and 6% on DM basis) on In vitro Dry Matter (IVDMD) and Organic Matter (IVOMD) digestibility of alfalfa hay and corn silage. For both forages, oil supplementation decreased IVDMD and IVOMD significantly (p<0.01) and increasing oil levels significantly (p<0.05) decreased IVDMD and IVOMD of both forages but alfalfa hay was more susceptible to increasing oil levels than corn silage. In experiment 2, eight multiparous early lactation Holstein cows (42±12 DIM, 40±6 kg daily milk yield) were fed a total mixed ration supplemented with either 0% oil (Control), 2% Fish Oil (FO), 1% Canola Oil + 1% Fish Oil (COFO) or 2% canola oil according to a double 4x4 Latin square design to examine the effects of unsaturated oil on milk yield, DMI and nutrient digestibility. Each period lasted 3 weeks experimental analyses were restricted to the last week of each period. Diets consist of 20% alfalfa, 20% corn silage and 60% concentrate. Cows were housed in tie stalls and fed the TMR two times a day to allow 5-10% orts (as-fed basis). Experimental diets had no significant (p>0.05) effect on milk production but DMI decreased significantly (p<0.05) in FO diet. Digestibility of OM and NDF were significantly (p<0.05) decreased in FO diet in comparison with three other diets, ADF digestibility was decreased significantly (p<0.05) in all oil containing diet in comparison with control but fat digestibility was not affected by treatments (p>0.05). Results of the current experiments shows that combination of fish oil and canola oil in 2% of dry matter had less negative effects on nutrient digestibility of forages and total mixture rations.
T.S. Vafa, A.A. Naserian, A.R. Heravi Moussavi, R. Valizadeh and M. Danesh Mesgaran, 2009. Effects of Different Levels of Fish Oil and Canola Oil on in vitro and in vivo Nutrient Digestibility. Research Journal of Biological Sciences, 4: 1221-1226.