Riboflavin for laying hens fed organic winter diets: effects of different supplementation rates on health, performance and egg quality

Figures & data

Table 1. Components, nutrient and riboflavin concentrations in the feeds (at 90% dry matter)

Treatment	R4.5^1	R3.0^1	R1.5^1
Main components (g kg^−1)^2
Soybean cake	301	301	301
Maize	250	250	250
Wheat	155	155	155
Calciumcarbonate	80	80	80
Sunflower cake	50	50	50
Grass meal	30	30	30
Wheat meal	30	30	30
Sorghum	30	30	30
Oat meal	30	30	30
Nutrients, minerals, vitamins
Crude protein (g kg^−1)^3	208 ± 3.8	207.3 ± 5.4	211 ± 5.4
Crude fat (g kg^−1)^3	57.0 ± 0	57.3 ± 1.7	57.0 ± 0
Crude fibre (g kg^−1)^3	51.3 ± 0.47	51.7 ± 0.94	51.3 ± 1.25
Crude ash (g kg^−1)^3	142 ± 31.8	137 ± 3.9	132 ± 25.5
Metabolisable energy (MJ kg^−1)^2	11.0	11.0	11.0
Lysine (g kg^−1) ^2	11	11	11
Methionine (g kg^−1)^2	3.6	3.6	3.6
Calcium (g kg^−1)^2	37.6	37.6	37.6
Phosphorus (g kg^−1)^2	5.4	5.4	5.4
Sodium (g kg^−1)^2	1.8	1.8	1.8
Iron (Fe-(II)-sulphate) (mg kg^−1)^4	50	50	50
Calciumiodate (mg kg^−1)^4	0.78	0.78	0.78
Manganoxide (mg kg^−1)^4	70	70	70
Zincoxide [mg kg^−1]^4	75	75	75
Sodiumselenite (mg kg^−1)^4	0.2	0.2	0.2
Vitamin A (IU kg^−1)^4	12,500	12,500	12,500
Vitamin D3 (IU kg^−1)^4	2500	2500	2500
Vitamin E (mg kg^−1)^4	63	63	63
Riboflavin (mg kg^−1)^5 week 1	6.07	5.33	3.34
Riboflavin (mg kg^−1)^5 week 8	4.94	4.41	2.83
Riboflavin (mg kg^−1)^5 week 18	4.96	4.50	3.12

¹Feeds supplemented with either 4.5 (R4.5), 3.0 (R3.0) or 1.5 (R1.5) mg riboflavin kg⁻¹ feed. ²Values as provided by the producer. ³Analysed in triplicate according to VDLUFA (2004). Data with standard deviation. ⁴Supplemented as premix as provided by the producer. ⁵Riboflavin concentration as measured by HPLC in the total feed (contains intrinsic and added riboflavin), n = 1 per sample.

Figure 1. (a) Daily feed consumption per hen in g (dots are mean values per pen); (b) laying performance per week in % (dots are mean values per pen); (c) individual body weight in kg. Lines represent model estimates for the three supplementation treatments R4.5 (4.5 mg riboflavin kg⁻¹ feed), R3.0 (3.0 mg riboflavin kg⁻¹ feed) and R1.5 (1.5 mg riboflavin kg⁻¹ feed). In b) weekly values above 100 % are explained by variation in time of sampling of eggs between days. n.s.: not significant. The experiment lasted from age weeks 25 to 43 of the hens. Week 1 data were used as correction covariable for the analyses.

Table 2. Organ weights (model estimates and 95% confidence intervals) with different rates of riboflavin supplementation

Outcome variable^2	Treatment			p-value, Treatment
	R4.5^1	R3.0^1	R1.5^1
Heart weight (g)	7.6 (7.2–8.1)	7.7 (7.3–8.2)	7.5 (7.1–7.9)	0.78
Pancreas weight (g)	5.0 (4.5–5.2)	4.7 (4.2–5.3)	4.7 (4.3–5.2)	0.58
Spleen weight (g)	1.9 (1.7–2.2)	1.9 (1.7–2.2)	1.9 (1.7–2.2)	0.99
Liver weight (g)	47.4 (43.1–52.0)	47.5 (43.0–52.4)	43.6 (39.1–48.4)	0.05^3

¹Feeds supplemented with either 4.5 (R4.5), 3.0 (R3.0) or 1.5 (R1.5) mg riboflavin kg⁻¹ feed. ²Across both dates of slaughter (n = 12 per treatment). ³The post hoc test showed no differences between the individual treatments.

Figure 2. (a) Total plumage score; (b) proportion of hens with lesions (lesion score < 8) and (c) proportion of hens with keel bone damage. Lines represent model estimates for the three supplementation treatments R4.5 (4.5 mg riboflavin kg⁻¹ feed), R3.0 (3.0 mg riboflavin kg⁻¹ feed) and R1.5 (1.5 mg riboflavin kg⁻¹ feed). n.s.: not significant. Post-hoc multiple comparisons among treatments for week 18 were never significant. The experiment lasted from age week 25 to 43 of the hens. Week 1 data were used as correction covariable for the analyses.

Figure 3. (a) Total egg weight; (b) egg yolk weight; (c) egg shell weight; (d) egg shell strength. n = 60 per treatment and day. Lines represent model estimates for the three supplementation treatments R4.5 (4.5 mg riboflavin kg⁻¹ feed) R3.0 (3.0 mg riboflavin kg⁻¹ feed) and R1.5 (1.5 mg riboflavin kg⁻¹ feed). n.s.: not significant. Post-hoc multiple comparisons among treatments for week 18 were never significant. The experiment lasted from age week 25 to 43 of the hens. Week 1 data were used as correction covariable for the analyses.

Figure 4. Yolk colour: (a) L* values (brightness); (b) a* values (red-green axis) (c) b* values (yellow-blue axis). n = 60 per treatment and day. Lines represent model estimates for the three supplementation treatments R4.5 (4.5 mg riboflavin kg⁻¹ feed) R3.0 (3.0 mg riboflavin kg⁻¹ feed) and R1.5 (1.5 mg riboflavin kg⁻¹ feed). n.s.: not significant. The experiment lasted from age week 25 to 43 of the hens. Week 1 data were used as covariable for the analyses.

Table 3. Riboflavin concentration (model estimates and 95% confidence intervals) in mg 100 g⁻¹ egg yolk (week 7 and 18, n = 3) and liver (week 11 and 18, n = 3) with different rates of riboflavin supplementation

	Week	Treatment			p-value
		R4.5^1	R3.0^1	R1.5^1	Week	Treatment	Interaction
Riboflavin mg 100 g^−1 egg yolk^2	7	0.56 a^3 (0.52–0.59)	0.56 a (0.53–0.59)	0.44 b (0.41–0.47)	0.79	< 0.01	0.14
	18	0.59 a (0.56–0.62)	0.55 a (0.52–0.59)	0.42 b (0.39–0.45)
Riboflavin mg 100 g^−1 liver^2	11	1.79 ab (1.73–1.85)	1.85 a (1.79–1.92)	1.69 b (1.62–1.75)	< 0.001	< 0.01	0.46
	18	2.18 a (2.11–2.24)	2.20 a (2.14–2.26)	1.98 b (1.91–2.04)

¹Feeds supplemented with either 4.5 (R4.5), 3.0 (R3.0) or 1.5 (R1.5) mg riboflavin kg⁻¹ feed. ²The concentrations measured in week 1 were used as a baseline-covariate in the model and are therefore not displayed. ³Means, in rows, followed by different letters are significantly different at p < 0.05.

VDLUFA. 2004. MB III 4.1.1 VDLUFA. Methodenbuch der VDLUFA, band III. [accessed 2021 Jan 23]. https://www.vdlufa.de/Methodenbuch/index.php?lang=de

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