Optimal Dietary Level of 1α,25-Dihydroxycholecalciferol for Eggshell Quality in Laying Hens

Abstract

The optimal dietary level of 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] for eggshell quality was established. White Leghorn hens, 59 wk of age, were fed one of eight diets that contained the same basal ingredients, including 3.1% calcium, but different levels (microgram/kg) or forms of calciferol supplements: no calciferol supplement of any form (56 hens); 27.5 (control) or 55.0 micrograms of cholecalciferol (56 hens each); 3, 5, or 7 micrograms of 1,25-(OH)2D3 (28 hens each); 5 micrograms of 24,25-dihydroxycholecalciferol [24,25-(OH)2D3] with 28 hens; 5 micrograms each of 1,25-(OH)2D3 and 24,25-(OH)2D3 (28 hens). All groups were fed the control diet prior to the 21-wk treatment. The group fed 5 micrograms 1,25-(OH)2D3/kg diet ranked first in specific gravity (SG), e.g., 1.081 versus 1.077 for the control group at Week 21 (P less than .05). The group fed 7 micrograms 1,25-(OH)2D3/kg consumed 30% less feed and laid 20% fewer eggs than the control, but shell quality was not affected. The groups receiving no calciferol supplement or receiving only 24,25-(OH)2D3 laid eggs with significantly lower SG than the control after 2 wk of treatment (1.072 or less versus 1.082 at Week 2). The rest of the treatment groups mentioned were comparable to the control in eggshell quality and egg production. Groups fed the combination of 1,25-(OH)2D3 and 24,25-(OH)2D3 per kilogram of feed, or 1,25-(OH)2D3 alone at 5 micrograms/kg, had significantly higher tibial weights relative to the control group. All groups receiving the diets without cholecalciferol supplementation had markedly reduced hatchability. It was concluded that the optimal dietary level of 1,25-(OH)2D3 for improving eggshell quality without affecting egg production was approximately 5 micrograms/kg and the toxic level was 7 micrograms/kg.

Cestrum diurnum leaf as a source of 1,25(OH)2 Vitamin D3 improves egg shell thickness

“…Present study has shown a good response in FCR in layers fed C. diurnum leaf powder. Tsang et al [16] also observed that feed consumption progressively decreased with increased dietary 1,25(OH) 2 D 3 . Probably, C. diurnum leaf which contain enough 1,25(OH) 2 D 3 levels must have resulted in lesser consumption of feed.…”

“…If we compute the additional eggs gained by preventing the drop due to the inclusion of C. diurnum leaf powder in the layer feed would result in extra eggs of about 25 per bird for the entire egg laying period of a hen. Tsang et al [16] demonstrated that decreased egg production is related to the ageing process in the layers. Though present study also on par with literature with respect to the age but the egg production drop was prevented to a larger extent up to 72 weeks in C. diurnum leaf powder fed layers suggests that 1,25(OH) 2 D 3 maintains the egg production at higher levels.…”

“…Based on this relationship, an estimated 14 times reduction in cracked eggs can be expected by feeding layers with C. diurnum leaf powder. There will be no residue problem because 1,25(OH) 2 D 3 does not get into the egg from hen plasma in any appreciable amounts [16].…”

Research Note: Calcitriol Reduces Egg Breakage

“…Tsang et al (1990b) have shown further that the optimal dietary level of calcitriol is 5 ug/kg, and that there is a very narrow margin between the optimal level and the toxic level (7 ug/kg). However, there have been few studies to test the direct effect of these metabolites on egg breakage.…”