The effects of incorporation of canola, soybean and fish oils to the diet on growth performance and nutrient digestibility in fattening lambs

In recent years, the supplementation of farm animal’s diet with oils has received attention, due to their content of some fatty acids beneficial to human health, such as linoleic and linolenic acids. This study was carried out to investigate the effects of different plant sources of beneficial fatty acids (canola oil and soybean oil) and fish oil, separately or mixed on growth performance and nutrient digestibility in fattening lambs.
Thirty-five male lambs with an initial body weight of 27.8 ± 2 kg and 4-5 months old were used in a completely randomized design for a 84-day feeding experiment with a 14-day adaptation period. Experimental treatments included: 1- control diet based (without oil), 2- diet with 3 % fish oil, 3- diet with 3 % canola oil, 4- diet with 3 % soybean oil 5- diet with 1.5 % fish oil 1.5 % canola oil, 6- diet with 1.5 % fish oil 1.5 % soybean oil, 7- diet with 1.5 % canola oil 1.5 % fish oil. Five lambs were then randomly allocated to each treatment. At the 70 day of period faeces output and feed intake samples were collected to determination of nutrient digestibility with acid insoluble ash method.
The results of current study showed that the experimental diets had significant effect on daily weight gain of lambs (P0.05). Oil supplementation did not affect on dry matter intake (DMI) and feed conversion ratio (FCR) during total feeding trial (P>0.05). Digestibility of organic matter, neutral detergent fiber, acid detergent fiber and ether extrac did not affected, but digestibility of dry matter (DM) in control group was higher than that of other treatments (P The results of current study showed that soybean oil and canola oil at 3% can be used in lamb’s finishing diets without adverse effect on performance of lambs. While, the use of fish oil at this level is not recommended.