Cb. Dabbert et al., EXAMINATION OF THE DIETARY METHIONINE REQUIREMENTS OF BREEDING NORTHERN BOBWHITE, COLINUS-VIRGINIANUS, Poultry science, 75(8), 1996, pp. 991-997
Adult Northern bobwhite were used to test the hypothesis that dietary
methionine levels recommended by the NRC for breeding quail are excess
ive for wild bobwhite. We tested the hypothesis by comparing immunocom
petence, reproductive performance, and chick viability of Northern bob
white hens fed diets containing low (0.31%), moderate (0.39%), or high
(0.47%) concentrations of methionine. Chick viability was determined
by assessing immunocompetence, including evaluating the ability of hen
s to passively transfer immunity to their chicks. Hens were fed the ex
perimental diets for 6 wk on an ad libitum basis. After 6 wk, methioni
ne treatment had no measurable effect (P greater than or equal to 0.20
) on hen phytohemagglutinin wing web indices, organ weights, or serum
anti-Pasteurella multocida titer indices. Mean egg weight, percentage
egg production, total cumulative egg production, yolk weight, yolk vol
ume, and percentage fertile and percentage hatch of fertile eggs did n
ot differ (P greater than or equal to 0.12) among diet treatments. Amo
unt of albumen in eggs produced by hens fed the high methionine diet a
veraged 0.27 g more (P = 0.003) than eggs of hens fed the low methioni
ne diet. Anti-P, multocida titer of yolks from eggs in Week 6 were not
different (P = 0.36) between birds fed the high and the low methionin
e diets. The mortality rate of chicks after challenge with 23 cfu of P
. multocida was not different (P greater than or equal to 0.05) among
diets. Chicks hatched from eggs laid by vaccinated hens during Weeks 2
and 3, however, had lower (P < 0.05) mortality than chicks of unvacci
nated hens. It appears a dietary methionine concentration of 0.3% may
be sufficient for wild Northern bobwhite to produce viable chicks.