Abdominal Leaf Fat Separation As a Result of Evisceration of Broiler Carcasses

Separation of abdominal leaf fat (ALF) as a consequence of evisceration of broiler carcasses was studied in a series of three experiments. Effects of dietary energy, sex, age at slaughter, growth rate, day-old weight, and giblet weights on this separation were evaluated. As a result of evisceration, four separations were identified and quantitated. Fat pad as a percent of total ALF represented 58.7% in females and 60.4% in males, fat dissected from the gizzard represented 20.7% (females) and 19.6% (males), viscera 17.2% (females) and 16.8% (males), and heart 3.4% (females) and 3.2% (males) of the total ALF. No differences (P>.05) in location of ALF was found due to sex, although the females had more (P<.05) total ALF than males. Dietary energy increase resulted in more (P<.05) ALF in females slaughtered at 7 weeks and in both males and females slaughtered at 8 weeks. Females at 7 weeks fed 3355 kcal metabolizable energy (ME)/kg and at 8 weeks on all three energy levels had more ALF than males. Only females fed 3080 and 3630 kcal ME/kg had increased (P<.05) ALF due to increased age from 7 to 8 weeks. Energy level and sex, but not age, produced differences (P<.05) in location of ALF after evisceration. Eight-week-old males fed 3080 and 3680 kcal ME/kg had larger fat pads than females fed the same rations. Fat pads of 7-week-old females increased as dietary energy was increased from 3080 to 3630 ME/kg. Gizzard, viscera, and heart ALF were not affected by dietary energy, sex, or age. Changes in total ALF did not result in changes in relative percentages of the four separations. Carcasses were divided into a low group, where ALF represented <3% of live weight, and a high group, where ALF represented >4% of live weight. At 7 weeks, 35.0% of females and 20.8% of males were in the high group compared to 24.0% of females and 40.6% of males in the low group. At 8 weeks 53.2% of females and 23.9% of males were in the high group compared to 9.0% of females and 28.4% of males in the low group. Growth rate and day-old weights were not different (P>.05) for the two groups. Gizzard and heart weights did not substantially affect the location of ALF as a result of evisceration. Location of ALF as a consequence of evisceration were different (P<.05) when the two groups were compared at each slaughter age. The low group deposited fat in the fat pad more slowly than the high group.