EFFECTS OF ADDED LARD FED TO BROILER-CHICKENS DURING THE STARTER PHASE - 2 - SERUM-LIPIDS

The effects of lard added to starter diets on various serum lipids wer e determined in broiler chickens between 14 and 42 d of age. Nonisocal oric starter diets were formulated to contain either 0, 3, or 7% added lard, where the megacaloric percentages of all major nutrients were h eld constant. Birds received either 0, 3, or 7% added lard in starter diets through 10 d of age (S1), followed by either 3 or 7% added dieta ry lard through 21 d of age (S2). All possible combinations of the thr ee S1 diets and two S2 diets yielded six total dietary treatments. A c ommon grower diet was provided after 21 d. Concentrations of various s erum lipids were determined weekly from 14 to 42 d of age. The effects of both the S1 and S2 diets on total cholesterol, low density lipopro tein cholesterol (LDLC), and high density lipoprotein cholesterol (HDL C) were inconsistent and were influenced by sex between 14 and 42 d of age. However, serum triglycerides and very low density lipoprotein ch olesterol concentrations showed progressive increases over the 14 to 4 2 d period in birds that received dietary lard at either level in the S1 diet. These same serum constituents also increased to the greatest extents over the same period when birds were provided 3% added lard in the S2 diet. It was concluded that the response of broiler chickens b etween 14 and 42 d to different levels of dietary lard were influenced by age of feeding during the starter period. Furthermore, the specifi c effects of the diets on serum cholesterol, LDLC, and HDLC concentrat ions between 14 and 42 d varied with the sex and age of the bird.