Mm. Mashaly et al., Influence of genetic selection for antibody production against sheep bloodcells on energy metabolism in laying hens, POULTRY SCI, 79(4), 2000, pp. 519-524
Genetic selection in chickens has been utilized to enhance immune responses
that may influence resistance to diseases. It is important, however, to in
vestigate the effects of this selection on other physiological processes. T
herefore, this study was conducted to determine whether selection for antib
ody (Ab) production against SRBC has an effect on energy metabolism. Laying
hens from three lines were used in this study, two of which were selected
for 15 generations for Ab response against SRBC, and the third was nonselec
ted and randombred. The hens used were from four different groups. The firs
t two groups were from the lines that were selected for either high (SH) or
low (SL) Ab production. The second two groups were control birds (nonselec
ted) that had either high (CH) or low (CZ,) Ab titers that were similar to
those in the SH and SL lines, respectively. The birds were housed in climat
e-respiration chambers. Body weights and energy metabolism were measured. B
ody weights of SL hens were significantly (P < 0.05) higher than those of S
H hens. However, the BW for the two nonselected groups were similar but sig
nificantly less than the Si, group. Energy partitioning was similar in all
groups; however, ME for maintenance for the selected groups (119 kcal.kg(-0
.75).d(-1)) was numerically, but not significantly (P < 0.09), higher than
that of the nonselected groups (112 kcal.kg(-0.75).d(-1)). These results su
ggest that divergent selection for Ab may result in an increase in the requ
irements of energy for maintenance, which is not directly related to the am
ount of Ab produced. Furthermore, these results support previous findings o
f the presence of a negative correlation between BW and the levels of Ab in
selected lines.