Abstract

The feed value of palm kernel cake (PKC) from two expeller sites and two hydrothermal production facilities were assessed using 30 laboratory rats as a model. Following chemical analysis, the PKC were incorporated at 0% (control, CON) or 35% (w/w) into isonitrogenous maize-based diets (2.9% N, DM basis) and fed to individually caged albino rats for 28 days (n=6). All PKC diets included 0.5% (w/w) Alzyme Vegpro (Alltech Canada, Guelph, ON). PKC from expellers (E1, E2) contained more (P<0.05) fatty acids (FA) and less (P<0.05) crude protein (CP) than did PKC from hydrothermal production (H1, H2), averaging 15.8% vs. 7.7% FA and 13.3% vs. 19.7% CP (DM basis), respectively. Lauric, oleic, myristic and palmitic acids were predominant in PKC, accounting for 84% of total FA. E1 and E2 had higher (P<0.05) essential amino acid contents (average 67.1% of total AA) than did H1 or H2 (average 64.1%). Gain and feed efficiency (FE; feed/gain) were similar (P>0.05) between rats fed E1 or E2 diets and those fed CON (2.1 and 2.2 g/day vs. 2.2 g/day; 4.7 and 4.3 g/g vs. 5.3, respectively), but were reduced (P<0.05) in rats fed H1 or H2 diets (1.5 and 1.3 g/d gain; 7.1 and 7.0 FE) compared with CON. This study indicated that expeller-produced PKC could potentially be included in maize-based starter diets for pigs at up to 35% with no adverse effects on growth.

Key words: Amino acid, fatty acid, expeller, hydrothermal.