Effects of Exposing Broiler Breeders to Nicarbazin Contaminated Feed

Abstract

Ten-mo-old broiler feeds were fed nicarbazin (NCZ) at 0, 25, 50 and 100 ppm of their diet for 2, 4, or 6 days to simulate accidental contamination of their feed with the medicant. Reduced egg production was observed in all treatments except 25 and 50 ppm NCZ for 2 days. A consistent reduction in egg weight occurred only at the maximum treatment level of 100 ppm for 6 days. Reduction in hatchability was generally evident by Days 5 and 6 of the experiment except for the lowest treatment of 25 ppm NCZ for 2 days. Due partially to the low number of eggs set, no statistically significant reduction in hatchability was seen for the group receiving 50 ppm NCZ for 4 days, but hatchability had dropped over 17 percentage points (from 93.3 to 75.5%) by Days 5 and 6 of the experiment, and continued to drop to a low of 31% on Days 11 and 12 of the experiment. Shell pigmentation was the most sensitive characteristic measured, with significant depigmentation occurring after only 2 days of feeding 25 ppm NCZ. Generally, the severity and duration of effects were in proportion to medicant concentration and length of treatment time. Fertility was not influenced by the medicant.

Downregulation of ALAS1 by nicarbazin treatment underlies the reduced synthesis of protoporphyrin IX in shell gland of laying hens

“…Mitochondrial biogenesis in these cells also allows them to meet changing energy loads for production of various components of the eggshell, including eggshell pigment. Nicarbazin is one of the various factors that has been shown to cause reduced synthesis and/or deposition of protoporphyrin into eggshells, when fed to brown-egg laying hens at recommended dosages (50–125 mg/kg of feed) 35, 36 . Nicarbazin produces reversible pharmacological effects by causing decolouration of brown egg pigment, which is dosage dependent 37, 38 .…”

“…We also hypothesized, on the basis of the effects of nicarbazin on production of PP IX, that nicarbazin may disrupt the mechanism involved in PP IX production by either regulating the genes involved in its production or affecting the mitochondrial numbers in the cells, resulting in lower production of PP IX appearing in eggshells of nicarbazin fed brown-egg laying hens. Nicarbazin was used as a model as it has been shown to produce reversible loss of brown eggshell colour 36, 37 . Therefore, Experiment 1 was performed to study the expression of genes involved in the synthesis of PP IX at different stages of egg/eggshell formation.…”

On the use of pharmacological sterilisation to control feral pigeon populations

“…spotting and mottling of yolk, reduction of hatchability, reduction of egg production, visible loss of colour in brown-shelled eggs and, in some cases, decreasing egg weight). Those effects are already evident at lower dosages (Hurwitz et al 1975;Reece et al 1985;Jones et al 1990aJones et al , 1990bHughes et al 1991). Even though the molecular mechanisms by which nicarbazin affects reproduction have not been completely clarified in vivo, its negative effects on egg hatchability seem to be due to the degeneration of the vitelline membrane, which becomes more permeable thereby allowing yolk and albumen to mix together (egg yolk mottling) (Cunningham 1976(Cunningham , 1977Yoder et al 2006bYoder et al , 2006c.…”

Acute Depigmentation of Fertile Brown Eggs in a Commercial Layer Operation

“…Removal of the suspect feed and replacing it with the normal ration resulted in the reappearance of brown eggs within 48 hours. This trial had shorter periods of time for depigmentation and repigmentation than the study of Jones et al 5 but similar to the study of Hughes et al 3 Feed samples were taken from the 46-week-old flock, the 29-week-old flock, and the feeding trial. Feed was analyzed for 4,4Ј-dinitrocarbanilide (DNC), e a major component of NCZ that is also considered to be responsible for the brownshell egg depigmentation and poor hatchability.…”