The Effect of Cottonseed Products and Selected Feed Additives on Egg Yolk Discoloration

Vitelline Membrane Strength and Egg Yolk Mottling

“…Previous work in this laboratory, reported by Berry, et al, (1968) had indicated that yolk mottling resulting from cottonseed meal was found soon after oviposition.…”

“…Thus, only one position on each yolk can be measured and the yolk loses its physical identity after such measurements are made. Holder, et al, (1968) also found the vitelline membrane on yolks from hens fed a ration containing cottonseed meal required more negative pressure to rupture than did the yolks from hens fed a control ration.…”

“…A mottling score of "2" or "3" would be considered objectionable to the consumer. by Holder, et al, (1968). The equipment used for the vitelline membrane portion of the study is diagrammed in Fig.…”

“…An egg breaking table was used which incorporated a mirror allowing simultaneous examination of the top and bottom of the yolk. The method used to assign mottling scores was that of Berry, et al, (1968). The scoring range was O, 1, 2, and 3.…”

“…In a report of yolk defects resulting from various feed additives, including cottonseed meal, Berry, et al, (1968) presented ·a ·comprehensive review of the literature on· this subject. Their data indicated that mottled yolks were·evi-dent ·within two days after oviposition and that the expression of the defect reached a plateau after 15 days of storage.…”