RESPONSE OF WHITE LEGHORN AND RHODE ISLAND RED BREEDER HENS TO DIETARY DEFICIENCIES OF SYNTHETIC VITAMINS. 2. EMBRYO MORTALITY AND ABNORMALITIES

Abstract

Eggs from White Leghorn and Rhode Island Red breeder hens fed corn-soybean diets devoid of the synthetic vitamins biotin, B12, E, folacin, niacin, pantothenate or riboflavin were examined to ascertain embryo mortality age and embryo malformities and malpositions. Embryos were examined during wk 1 to 8 and wk 13 and 14 of treatment, and during 5 consecutive wk of subsequent vitamin fortification (15th-20th wk of trial). A deficiency of riboflavin had the most effect on pattern of embryo mortality age, and induced a clubbed-down condition. Malformities and malpositions in general, however, were not sensitive indicators of specific deficiencies. Prolonged deficiency of riboflavin with RIR induced sequential mortality peaks in 15–21 day, 8–14 day and finally 1–7 day embryos. The reverse situation, in terms of embryo mortality age was observed with niacin and vitamin B12. Embryo mortality during the 8–14 day period of incubation was not evident at any time with control-fed birds, or 3 wk after diets were refortified, suggesting that mortality during this period is a sensitive indicator of nutritional inadequacy of the breeder diet.