The influence of supplemental fat on rumen volatile fatty acid profle, ammonia and pH levels in sheep fed a standard diet

The effect of different types of fat supplementation on basic rumen parameters was estimated on three milking sheep fitted with rumen cannulae in a 3x3 Latin square design consisting of three experimental diets differing in the percentage of fat supplement. The basic ration for the control group consisted of meadow hay and concentrate (60:40) and was supplemented for experimental groups with rape seed oil, soyabean oil, linseed oil, tallow, Bergafat or fish oil at a level of 0 (control), 4, and 6% in dry matter. Samples of rumen fluid were analyzed for volatile fatty acids, ammonia (N-NH 3 ) and pH. The acetic acid level increased significantly (P<0.05) when 4 and 6% of soyabean oil was added to the ration. Similarly, addition of linseed oil increased (P<0.05) the level of acetic acid in experimental groups. A significant (PO.05) increase in the acetic acid level was observed when 6% Bergafat was added, whereas the level of this acid was reduced when 6% fish oil was added to the diet. The butyric acid level decreased significantly (PO.05) when the diet contained 6% linseed oil, and there was a decrease (PO.05) in isobutyric acid in both groups receiving fish oil. A slight but statistically significant (PO.05) increase in the isobutyric acid level when the diet was supplemented with 4% soyabean oil was also observed. The addition of rape seed oil and tallow