Citation of this paper

Supplement red yeast (Rhodotorula) and alga (Sargassum sp) in the diet of laying hens to improve egg yield and egg quality

Le Viet Phuong, Nguyen Thi Tuyet Le, Bui Huy Doanh, Bui Quang Tuan and Nguyen Thi Huyen

Department of Animal Nutrition and Feed Technology, Faculty of Animal Science, Vietnam National University of Agriculture, Trau Quy, Hanoi, Vietnam
nthuyencnts@gmail.com

Abstract

The experiment was conducted to evaluate the effects of supplementation Rhodotorula yeast and alga Sargassum powder (R-S) on egg yield and egg quality of Egypt hybrid hybrid laying hens. Three hundred and sixty of 18-week-old Egypt hybrid hens were selected for the experiment with 90 hens for each treatment. The treatments were: the control group without supplement of R-S while group with supplement of 1.0%, 1.5% and 2.0% R-S, respectively. The results showed that the cumulation of egg yield was greater in the 1.5 and 2.0 treaments, compared to the control. The feed consumption/10 eggs was lower in the 1.5 and 2.0 treaments when laying hens in 40-week-old. The egg yolk color was greater in the 1.5 and 2.0 treaments, however, the cholesterol content in eggs was lower in the 1.5 and 2.0 treaments, compared to the control. Supplementation of R-S did not affect on egg weight, egg shape, shell thickness, proportion of shell, proportion of egg white and proportion yolk. The results suggested that the appropriate level of supplement R-S in the diet of laying hens is 1.5%.

Keywords: egg yield, egg quality, yolk color, cholesterol

Introduction

Carotenoids are necessary substances which need to be presented in feed for laying hens. Besides carotenoids provide provitamin A, they are also biological antioxidants to protect cells, ovaries and increase egg yield. However, the carotenoid content in corn, cassava, rice bran is much lower than the requirement of laying hens. Consequence, laying hens often lack of yellow pigment, so they have a weak resistance and easy to get disease. The eggs yield and egg quality is reduced. The Rhodotorula yeast is capable to produce a large amounts of carotenoids, protozoan proteins, acetic acid, lipids and acetaldehyde. These products are used in the food processing, pharmaceutical and livestock production (Gabier et al 2005; Xue et al 2008; Schneider et al 2013). Among marine plants in Vietnam, Sargassum sp. is a very common and easily to harvest. Sargassum contains polyunsaturated fatty acids, polysaccharides, sterols, estigmasterol and β-sitosterol which have positive effects on physiological and metabolic processes in humans and animals. Sargassum is also rich in xanthophyll. Le Viet Phuong (2016) found that xanthophyll content in Sargassum was 1540.5 mg/kg of DM. With the desire to find a carotenoids and xanthophyll sources for laying hens, a product is created from the combination of Rhodotorula yeast and Sargassum (R-S). The objective of current study is to determine the effect of supplement R-S in the diet of laying hens on the egg yield and egg quality.

Materials and methods

Materials

- Rhodotorula yeast and alga Sargassum powder (R-S): including 20% Rhodotorula yeast powder, 40% alga Sargassum powder and 40% Dicalciumphosphate as a carrier. Rhodotorula yeast powder contains 79.4mg of total carotenoids / 100g of DM, 10.8mg of β-carotene / 100g of DM. Alga Sargassum powder contains 1590.4mg xanthophyll / kg of DM. The R&S was produced as described in Figure 1.

- Three hundred and sixty of 18-week-old Egypt hybrid laying hens

- The experiment was conducted at Animal reseach facility of Animal Science Faculty, Vietnam National University of Agriculture, Hanoi, Vietnam from October 2020 to May 2021.

Figure 1. Rhodotorula yeast and alga Sargassum powder

Experimental design:

The experiment was designed as presented in the Table 1.

Table 1. Design of experiment supplementation Rhodotorula yeast and alga Sargassum powder (R-S),%
Items	*(R-S), %*
Items	0	1.0	1.5	2.0

Number of hens	90 (30x3)	90 (30x3)	90(30x3)	90 (30x3)
Replications	3	3	3	3
Weeks of experiment	26	26	26	26
Hen breed	Egypt hybrid	Egypt hybrid	Egypt hybrid	Egypt hybrid
Supplement of R&S (%)	0.0	1.0	1.5	2.0

The laying hens were fed a complete diet in powder form. The R-S was added when the diet was mixed. The complete diet for laying hens was made according to the requirements of NRC (1994). The complete diet is presented in Table 2.

Table 2. Ingredients of chemical compositions of the complete diet for laying hens
Ingredients	% in the diet

Maize	55.2
Soybean meal	23.3
Rice bran	10.2
Tryptophan	0.2
Methionine	0.2
Lysine	0.1
Soybean oil	0.4
Tricalciphosphate	1.4
Lime	7.5
Premix	1.5
*Chemical compositions of the diet*
Crude Protein (%)	17.0
Crude Fibre (%)	3.1
Lipid (%)	4.4
Ca (%)	3.82
P (%)	0.71
Ash (%)	11.1
ME (Kcal/kg)	2751.0

Laying hens were housed on the floor with rice husk and sawdust. Laying hens were fed twice a day at 7:00am and 4:00pm. The hens were offered water ad libitum during the entire experiment. Eggs were collected once a day at 5:00 pm.

The measurement parametters

- Egg yield per week (eggs/hen/week):

-Eggs were weighted every week. Fifty eggs per week were randomly selected from each treatment and were weighted using an electronic balance, with an accuracy of ± 0.01g.

- Feed consumption/10 eggs (kg)

- Thirty eggs per week were randomly selected from each treatment per week to measure shell thickness; yolk index; egg-white index.

+ Shell thickness (mm):

The eggshell thickness was calculated by the average of the shell thickness (after removing the membrane) at 3 points: the large end, the small end and the equator. The shell thickness was measured using a palme ruler with an accuracy of ± 0.01mm.

+ Yolk index, egg-white index:

Yolk diameter, egg-white diameter was measured using a palme ruler with an accuracy of ± 0.01mm.

Where : h = yolk height (mm)

d = yolk diameter (mm)

Where: h = egg-white height (mm)

D = egg-white large diameter (mm)

d = egg-white small diameter (mm)

The yolk color: The yolk color was measured by comparing the color of yolk to the color standard of Roche scale. The color of Roche scale consists of 15 color bands, numbered from 01 to 15, the color bands are distributed from light to dark.

The cholesterol content in egg : Ten eggs were randomly selected from each treatment per week to determine the cholesterol content. The cholesterol content was dertemined by HPLC according to the method of Rong et al. (1999)

Statistical analysis

The different of egg yield and egg quality among treatments were analysed by ANOVA using the MIXED procedure of SAS (SAS, 2010). The model was:

Y = μ + Ti + εij(2)

where Y = the dependent variable, μ = the overall mean, Tj = the effect of treatment (i=1 to 4) and εij=the residual error term. The results are presented as the least squares means and standard error of the means. Differences among main effects were analysed using Tukey-Kramer’s multiple comparison procedure in the LSMEANS statement of SAS (SAS 2010) with effects considered significant at p≤0.05 and a trend at 0.05<p

Results

The cumulation of egg yield

The cumulation of egg yield is presented in Table 3. During 25 to 44 week-old of laying hens, the cumulation of egg yield were greater (P ≤ 0.005) in the 1.5 and 2.0 treatments, compared to the control and 1. In the end of experiment, the cumulation of egg yield in the 1.5 and 2.0 were 127.7 and 127.8 eggs/hen. While the cumulation of egg yield in the control and 1 were 126.2 and 126 eegs/hen.

Table 3. The cumulation of egg yield (eggs/hen)
Week of experiment	Age weeks of hen	*(R-S), %*				SEM	p
Week of experiment	Age weeks of hen	0	1	1.5	2.0	SEM	p

1	19	0.09	0.10	0.11	0.13	0.016	0.297
7	25	26.7^a	26.7^a	27.0^b	27.2^b	0.076	0.005
12	30	54.2^a	54.1^a	54.9^b	55.1^b	0.067	<.0001
17	35	80.2^a	80.2^a	81.2^b	81.4^b	0.126	0.0002
22	40	105.9^a	105.8^a	107.3^b	107.5^b	0.156	<.0001
26	44	126.2^a	126.0^a	127.7^b	127.8^b	0.197	0.0002
^ab Row means with different superscripts differ at p<0.05

Feed comsumption

Feed comsumption /10 eggs is presented in Table 4. Feed consumption/10 eggs tended to be lower (P = 0.076) in the 2.0, compared to the control when hens in 25 week-old. When hens in 40 week-old, the feed comsumption was lower (P = 0.005) in the 1.5 and 2.0. The hen need 1.33 to 1.47 kg feed to produce 10 eggs during the entire experiment.

Table 4. Feed consumption/10 eggs (kg)
Week of experiment	Age weeks of hen	*(R-S), %*				SEM	p
Week of experiment	Age weeks of hen	0	1	1.5	2.0	SEM	p

1	19	65.3	60.7	56.0	42.0	10.43	0.468
7	25	1.28	1.28	1.28	1.26	0.005	0.076
12	30	1.33	1.34	1.31	1.32	0.090	0.131
17	35	1.40	1.40	1.40	1.38	0.010	0.407
22	40	1.46^a	1.46^a	1.43^b	1.43^b	0.005	0.005
26	44	1.46	1.47	1.45	1.46	0.006	0.169
^ab Row means with different superscripts differ at p<0.05

The weight and shape of eggs

The weight and shape of eggs are presented in Table 5. The results showed that supplement R-S did not affect on the weight and shape of eggs.

Table 5. The weight and shape of eggs (n=150)
Week of experiment	Age weeks of hen	*(R-S), %*				SEM	p
Week of experiment	Age weeks of hen	0	1	1.5	2.0	SEM	p

Weight of eggs (g)
1	19	50.2	50.1	50.9	50.9	0.38	0.27
7	25	55.7	55.2	55.5	55.0	0.32	0.42
12	30	58.0	57.9	58.2	58.6	0.33	0.39
17	35	58.1	57.6	58.2	58.3	0.31	0.36
22	40	58.6	58.4	58.7	58.2	0.31	0.73
26	44	58.4	57.6	57.2	57.5	0.34	0.06
Shape of eggs
1	19	1.30	1.31	1.31	1.31	0.004	0.83
7	25	1.29	1.29	1.30	1.29	0.007	0.81
12	30	1.29	1.28	1.29	1.29	0.003	0.07
17	35	1.30	1.30	1.30	1.30	0.004	0.38
22	40	1.31	1.31	1.30	1.31	0.004	0.13
26	44	1.32	1.31	1.32	1.32	0.004	0.19

The quality of eggs

Some parametters related to the quality of eggs are presented in Table 6. Shell thickness, proportion of shell, proportion of egg white and yolk were similar among treatments. The yolk color was greater (P <.0001) in the 1.5 and 2.0, compared to the control and 1. Supplement R-S increased the yolk color from 7.55 point (control) to 10.90 point (2.0). However, the cholesterol content was lowest ((P <.0001) in the 1.5 treatment. Supplement R&S reduced the cholesterol content from 583.7 (mg/100g) in the control to 435.5 (mg/100g) in the 1.5 treatment.

Table 6. The quality of eggs (n=150)
Items	*(R-S), %*				SEM	p
Items	0	1	1.5	2.0	SEM	p

Shell thickness (mm)	0.33	0.33	0.33	0.33	0.004	0.712
Proportion of shell (%)	10.2	10.8	10.6	10.5	0.182	0.180
Proportion of egg white (%)	64.9	64.9	64.3	64.5	0.457	0.775
Proportion of Yolk (%)	24.9	24.4	25.0	24.9	0.455	0.726
Yolk color	7.55^a	8.65^a	10.60^b	10.90^b	0.308	<.0001
Cholesterol (mg/100g)	583.7^a	492.2^b	435.5^d	457.9^c	4.811	<.0001
^abcd Row means with different superscripts differ at p<0.05

Figure 2. Correlation between supplement R-S and yolk color

Discussions

Schwarz và Margalith (1965) supplemented 1-2% Rhodotorula mucilaginosa yeast in the laying hen diet. The main ingredients of the diet were 67.5% sorghum grain and 21% defatted soybean meal. Schwarz và Margalith (1965) found that the yolk color increased 3.0 point in the control diet to 6.8 point in the 2% R. mucilaginosa supplement diet. The results of yolk color in the current experiment is in line with fouding of Schwarz và Margalith (1965). In the current study, the yolk color also increased from 7.55 point in the control to 10.90 point when supplement 2% of R-S in the diet of laying hens. Pârvu and Paraschivescu (2014) supplemented R. rubra yeast with 1.5 and 3% in the diets of laying hens. The authors reported that the egg yield was similar among treatments, However, the yolk color was significantly increased. The yolk color of the control group was lower than10 point, while the yolk color in the diet with 1.5% R. rubra yeast was 11 point and in the diet with 3.0 % R. rubra yeast was 13 point.

Pérez and Guerra (1978) supplemented alga Ulva fasciata in the diet of laying hens, the results showed that the yolk color increased, compared to the control diet. Sargassum sp powder has also been used at 4; 5 and 6% in the diet of Egypt hybrid laying hens. The results showed that using 5% of Sargassum sp in the diet had a positive impact on egg quality, yolk color increased from 9.47 point (in the control diet) to 11.33 point, egg shell thickness increased from 0.346 (in the control diet) to 0.349 mm. However, supplement of Sargassum sp did not affect on the egg yield and feed comsumption/10 eggs (Le Viet Phuong, 2016).

Yuan (2008) reported that alga can be an alternative source to reduce cholesterol content in eggs, because alga contains polyunsaturated fatty acids, polysaccharide, sterols, estigmasterol and β-sitosterol. Silvia et al. (2012) supplement alga powder in the diet of Leghorn laying hens. The results showed that the cholesterol content of eggs was reduced from 416.28 ( mg/100 g) in the control diet to 309.05 mg/100 g in the treatment diet.

Conclusions

Supplementation of Rhodotorula yeast and alga Sargassum powder (R-S) at 1.5% and 2.0% in the diet of laying hens increased the cumulation of egg yield.
Supplementation of R-S at 1.5% and 2.0% in the diet of laying hens increased the yolk color
Supplementation of R-S at 1.0%; 1.5% and 2.0% in the diet of laying hens reduced the cholesterol content in eggs.
Supplementation of R-S did not effect on feed comsumption/ 10 eggs, egg weight, egg shape, shell thickness, proportion of shell, proportion of egg white and proportion yolk.
The appropriate level of supplement R-S in the diet of laying hens is 1.5%.

Acknowledgements

The experiment was funded by the Minister project "Supplement red yeast ( Rhodotorula) and alga (Sargassum sp) in the diet of laying hens to improve the egg quality and egg yield". The authors thanks to the students and the members participating in the project for their assistance during experiment.

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