Interactions between fats of differing chemical content: apparent availability of fatty acids.
1. Tallow (A) and rape oil (E) were obtained for evaluation. They were blended in the ratios A95:E5, A90:E10 and A80:E20. The three blends together with the two pure fats were each included at 40, 80 and 120 g/kg into a basal diet. 2. The experimental diets were evaluated for apparent availability (g/kg) of the fatty acids palmitic (C16:0), stearic (C18:0), oleic (C18:1) and linoleic (C18:2) using 6 replicates of a cage of two male broiler chicks 14 d old and 8 replicates of a cage of one Rhode Island cross cockerel approximately 1 year old. Diets were fed for 72 h then removed for 24 h. This was followed by a 48 h period when food was available ad libitum and a further 24 h starvation. A total collection of excreta was undertaken for the latter 72 h period. 3. Evaluation of apparent available fatty acid (AAFA g/kg fatty acid) was achieved by linear regression. 4. All results indicated a progressive increase in AAFA with both chicks and adults for C16:0 and C18:0 with increasing proportions of the more unsaturated rape oil in the fat blends and for C18:1 and C18:2 with chicks. 5. Evaluation of AAFA by quadratic regression indicated an additional effect of rate of inclusion for C16:0 and C18:0 with chicks and adults and for C18:1 with chicks.
Wiseman
J
J
University of Nottingham School of Agriculture, Loughborough, Leics England.
Lessire
M
M
D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004041:Dietary Fats / Q000032:analysis / Q000378:metabolism*; D004734:Energy Metabolism; D005223:Fats / Q000032:analysis / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated; D008297:Male; D009753:Nutritive Value; D010938:Plant Oils / Q000032:analysis / Q000378:metabolism; D000074262:Rapeseed Oil
D004041:Dietary Fats; D005223:Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D000074262:Rapeseed Oil; C013698:tallow