The Effects of Vitamin D Supplementation to Peak-producing Hens Fed Diets Differing in Fat Source and Level on Laying Performance, Metabolic Profile, and Egg Quality

Abstract

This experiment was designed to examine the effects of supplemental vitamin D on laying performance, metabolic profile and egg quality of hens fed diets containing different fat sources and levels. Lohman strains (n = 480) were assigned to one of 10 diets: basal diet (BD), BD plus 2.5 and 5.0% sunflower oil (SO) or tallow (T) at vitamin D provided 1× and 3× of the current recommendation. The experiment lasted from week 30 to 44 of age. Each diet was tested in 12 replicate cages of 4 hens. Production, metabolism, and egg quality data were subjected to three-way ANOVA. Both fats decreased feed intake (FI) as compared to BD. Increasing SO and T levels linearly decreased and quadratically increased FI, respectively. The dietary factors did not affect egg production (EP) and egg weight. Vitamin D supplementation increased and decreased EP when diets contained SO and T, respectively. Feed conversion efficiency (FCE) for hens fed SO was lower than for hens fed T. However, increasing T level improved FCE, whereas increasing SO level worsened FCR. Vitamin D supplementation increased serum vitamin D and glucose concentrations. Vitamin D supplementation also caused a decrease and an increase in serum vitamin D concentration when diets contained SO and T, respectively. Serum glucose concentration for hens fed SO was lower than hens fed T. Increasing fat level linearly increased serum triglyceride and VLDL concentrations, regardless of the fat type. Increasing SO level linearly decreased serum cholesterol concentration. Vitamin D supplementation did not alter lipid metabolites. The dietary factors did not affect serum total protein, Ca, and P concentrations. As compared with BD, feeding SO decreased dry tibia and ash weights more than feeding T. Vitamin D supplementation tended to increase dry tibia weight and decrease tibia ash weight. Eggshell strength and thickness, yolk and albumen indexes, and Haugh unit were not responsive to the dietary factors. Eggshell strength quadratically increased with increasing T level. Yolk color for hens fed SO was lower than for hens fed T. The dietary factors did not affect most of yolk fatty acids. Increasing SO level quadratically decreased yolk C 18:2 concentration. Vitamin D supplementation increased and decreased yolk C 18:2 concentration when diets contained SO and T, respectively. In conclusion, increasing fat level improved laying performance without altering metabolic profile and egg quality. Vitamin D supplementation had minor alteration effects on laying performance, metabolic profile, and egg quality in response to fat feeding.

Effects of dietary humate supplementation on performance, egg quality and egg yolk fatty acid composition in layers

“…The mechanism whereby humate affects the FA composition of egg yolk is largely unknown. Concentrations of FA in animal fats are reported to be highly variable depending upon various factors such as animal age and diet 19. Alteration in FA composition of egg yolk could result from humate being of plant origin and relate to it being derived from plant matter decomposed by bacteria.…”

Effects of 25-hydroxycholecalciferol and soy isoflavones supplementation on bone mineralisation of quail

“…Vitamin D has regulatory effects on calcium and phosphorus ANOVA Probabilities homeostasis by stimulating bone calcium mobilisation and inhibiting urinary calcium excretion when hens are calcium deficient. The mode of action is through molecular mechanisms involving bone cells and vitamin D binding proteins (Soares et al, 1995;Sugiyama and Kusuhara, 2001;Turgut et al, 2006). Heat stress decreases growth rate and bone mineralisation as well as concentrations of vitamins and minerals such as vitamins C, E, D and A, Ca, P and Zn in poultry (Sahin and Kucuk, 2003).…”

Effects of Feeding Tallow and Plant Fat to Laying Hens on Performance, Egg Quality and Fatty Acid Composition of Egg Yolk

“…n-3= omega-3 fatty acid, n-6= omega-6 fatty acid, SFA= Saturated fatty acid, MUFA= Monounsaturated fatty acids; PUFA= (tallow, sunflower, fish and flaxseed oil) fed to broilers (Newman et al,3002) layers (Grobas et al, 2001) showed no changes on performance parameters (FI, FCR and EP). However, Turgut et al (2006) reported that dietary fat sources affected laying performance.…”

“…None of the inner and other egg quality parameters were influenced by dietary treatments (P>0.05). Others have also shown that dietary fat sources had no significant effect on egg quality parameters (Baucells et al, 2000;Grobas et al, 2001;Turgut et al, 2006).…”