Effect of different fat sources on some enzyme activities in laying hens

To examine the effects of different vegetable and animal fat sources on some enzyme activities and protein metabolism, 270 laying hens were randomly divided into 9 groups of 30 each (one control and 8 experimental groups). In experiment 1 and 2, four experimental groups (II, III, IV and V) each were fed with a diet supplemented with 2% or 4% tallow (TO), mixture of tallow-flaxseed oil (1:1 w/w) (MTFO), sunflower (SO) and flaxseed oils (FO), respectively for 8 wks. Me serum AST, ALP, ALT and LDH activities in groups of 4% TO and MTFO were higher than that of control group (P<0.05). The 2% level of TO, MTFO (1:1 w/w), SO and FO and 4% of SO and FO did not affect various tissues. However, 4% TO and MTFO (1:1 w/w) significantly affected various tissues. It is concluded that 4% TO and MTFO, used as energy sources in diet of layers, are harmful for laying hens.