Organ Weights
The absolute and relative weights of the liver, ovary,
and abdominal fat were higher in LIB than in R fed
hens, a finding that is consistent with data of Chen et
al. (2006) and Renema et al. (1999a,b) in young broiler
breeder hens.
Dietary fiber decreased absolute and relative lipid
accumulation in the abdominal cavity consistent with
data of Yusrizal and Chen (2003) in broilers fed diet
supplemented with inulin. Dietary fiber reduced liver
weight but did not affect the relative weight of this
organ. Daubioul et al. (2002) observed that dietary inulin
reduced hepatic TG content and fat deposition in
rats. Also, Velasco et al. (2010) reported that dietary
inulin decreased total lipid concentration in the liver of
broilers. Akiba and Matsumoto (1978) reported that
liver weight was increased in force-fed broilers, but the
effects were reduced when 4% cellulose was included in
the diet.
The absolute and relative weights of the liver, ovary,
and abdominal fat were reduced as the CP content of
the diet increased. Lilburn and Myers-Miller (1990) reported
a decrease in fat pad weight as the CP level of
the diet increased from 16 to 23%. In contrast, Joseph
et al. (2000) reported that liver and abdominal fat pad
weights were not affected by the level of CP of the
diet during the prelay and early lay period of broiler
breeders. The reduction in liver weight observed with
increases in CP content of the diet agrees with data of
Rosebrough and Steele (1985) and Rosebrough et al.
(2002) who indicated that CP per se is a potent regulator
of de novo lipid metabolism in birds.
In conclusion, the increased BW observed with LIB
feeding of broiler breeder hens after peak of egg production
was associated with excessive liver and abdominal
fat deposition which resulted in negative effects on reproductive
traits including egg production and fertility.
The inclusion of inulin and cellulose in the diet reduced
feed intake and BW gain of the hens and improved
reproductive performance. An increase in dietary CP
reduced hen obesity. The combination of high CP and
the inclusion of fiber in the diet did not have any synergistic
effect on organ weights or in any of the other
traits studied. Inclusion of additional fiber and increases
in CP content of the diet are recommended practices
to improve reproductive performance of broiler breeder
hens.