Effects of dietary red ginseng marc on egg production, egg quality and blood characteristics of laying hens

Abstract

A 45-day feeding trial was conducted to study the effect of red ginseng marc dietary supplementation on the egg production, egg quality and blood profiles of laying hens. One hundred and sixty ISA brown layers were allocated to four treatments (0%, 0.5%, 1% or 2% red ginseng marc) with four replicates per treatment (10 layers per replicate) in wire cages. There were no differences in egg production and egg quality among red ginseng marc as the number of days of treatments increased. However, albumen and eggshell weight exhibited some differences at 30–45 days and 45 days, respectively. Red ginseng marc caused a reduction in total cholesterol at 10 days and triglyceride levels at 10–45 days or an increase in high-density lipoprotein cholesterol levels at 10–45 days but does not affect low-density lipoprotein cholesterol levels at 10–45 days. No effects were observed in the blood profiles for all treatments, except for red blood cells at 30 and 45 days. It was concluded that 1% or 2% red ginseng marc supplementation to laying hens' diets decreases serum cholesterol concentrations.

Keywords:

• laying hens
• red ginseng marc
• egg traits
• serum cholesterol
• blood profiles

Introduction

Ginseng (Panax ginseng Meyer) is a perennial plant that has been used for centuries in Asian countries as an herbal medicine for the treatment of various diseases, due to its capacity to enhance immunity or inhibit inflammation (Lee et al. 2008). In general, ginseng may be separated into red ginseng and white ginseng based on the processing method used (Choi et al. 2011). For example, when ginseng is steamed using water vapour at 98–100°C for 2–3 h, red ginseng is obtained from the dried ginseng roots, which has a longer storage period than white ginseng (Lee et al. 2008; Kim and In 2010). In addition, red ginseng is known to have greater pharmaceutical efficacy and functionality than white ginseng, due to its high content of saponins (Kim and In 2010). Previous studies with animals have demonstrated the potential effects of ginseng as an immunization agent against various pathogens (Hu et al. 2003; Rivera et al. 2003). In a study by Jang et al. (2007), supplementing the diet of hens with the by-product of fermented wild ginseng culture was shown to improve egg production and egg quality. Many studies have indicated that saponin is a potentially bioactive ingredient (Ao et al. 2011a); however, the physiological role of saponins in plants and animals remains poorly established (Francis et al. 2002).

To the best of our knowledge, limited research has been published about the influence of dietary red ginseng marc on the egg quality and blood profiles of laying hens. Therefore, the objective of this research was to investigate the effects of red ginseng marc supplementation on the egg production, egg quality and blood profiles of laying hens across a 45-day feeding period.

Materials and methods

Animals, sampling and analysis

One hundred and sixty 76-week-old ISA brown laying hens were used in the present study. Hens were randomly allocated to four different dietary treatments, with four replicates; hence a total of 16 wire-caged pens each containing 10 birds were used. Laying hens were fed with one of four diets containing 0%, 0.5%, 1% or 2% red ginseng marc for 45 days. The lighting, ventilation and temperature of the facility were automatically controlled, with cages being equipped with shared-through feeders and nipple drinkers. Feed and water were available ad libitum. The standard industrial diets for layers contained corn, soybean meal, rapeseed meal, corn gluten meal and wheat bran (Table 1). Red ginseng marc was replaced by wheat bran at 0.5%, 1% and 2% levels.

Table 1. Composition of experimental diets (%).

	Concentration
Ingredients
Corn	52.19
Soybean meal	21.20
Rapeseed meal	2.10
Corn gluten meal	5.55
Animal fat	1.50
Wheat bran	6.50
Dicalcium phosphate	0.50
Limestone	10.00
Salt	0.20
DL-Methionine	0.09
Vitamin premix^a	0.07
Mineral premix^b	0.10
Total	100.00
Calculated values
Metabolizable energy (kcal/kg)	2820
Crude protein (%)	17.30
Methionine (%)	0.73
Lysine (%)	0.73
Ca (%)	0.38
Available P (%)	0.40

^a Vitamin premix provided the following (per kg of diet): Vitamin A, 20,000,000 IU; Vitamin D₃, 5,000,000 IU; Vitamin E, 30 IU; riboflavin, 3 mg; vitamin B₁₂, 30 mg; nicotimic acid, 44 mg; folic acid, 1.4 mg; biotin, 160 mg; thiamine, 2.2 mg; and pantothenic acid, 16 mg.

^b Mineral premix provided the following (per kilogram of diet): Mn, 60 mg; Zn, 50 mg; Fe, 40 mg; Cu, 6 mg; Se, 0.2 mg; I, 1 mg; and Co, 0.3 mg.

Daily egg production for each 15-day period was recorded throughout the experimental period. Egg production was calculated from the total number of eggs divided by the number of days. To assess egg, yolk, albumen and eggshell weight, the weight of 10 eggs per treatment (a total of 20 eggs per treatment) was measured with a digital balance. Subsequently, eggs were hard-boiled to separate the yolk, albumen and eggshells. Then the cooked yolk, cooked albumen and eggshell weight were separately determined with a digital balance. The 10 remaining eggs from each treatment were used to determine egg quality. Albumin height (mm) and yolk colour score were analysed with an egg multi-tester. Eggshell thickness (mm) was measured at three different points (the large end, equatorial region and small end) in the middle part of the egg using a dial gauge micrometre. The eggshell breaking strength (kg/cm²) was determined using an eggshell force gauge model II. On the 15th, 30th and 45th day of the experiment, five birds per treatment were randomly selected for blood sample collection. Blood was collected from the wing vein using a sterile syringe and needle and immediately transferred into vacuum tubes. For the serum analysis, samples were centrifuged at 2000×g for 30 min to isolate the serum. The serum was collected and stored at −20°C (for up to 2 days) until serum cholesterol and blood profile analysis. Total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides were analysed using an automatic analyzer and direct enzymatic kits. White blood cell (WBC), red blood cell (RBC), haemoglobin and hematocrit counts of the whole blood samples were evaluated using an automatic blood analyzer.

Statistical analyses

Experimental data were tested with ANOVA using the general linear model (GLM) procedure in SAS as a completely randomized design (SAS 2000). Differences among all treatments were tested with Duncan's multiple range tests (Duncan 1955). Variability in the data is reported as standard error of mean (SEM). A probability value of less than 0.05 was considered statistically significant. The experimental model used was:

where Y_ij, response variable; µ, the overall mean; v_i, ith treatment effects; and ε_ij, ith random error.

Results and discussion

Egg production and egg quality

Throughout the experiment, egg production, egg weight, yolk weight, albumen weight, and eggshell weight showed no differences (P ≥ 0.05) among red ginseng marc supplementation over time (Table 2). However, there were some differences (P ≤ 0.05) among treatments for albumen weight at 30 and 45 days and eggshell weight at 45 days (Table 2). Overall, this finding indicates that increasing levels of dietary red ginseng marc did not improve egg traits during the period of feeding. Our results support those of Kim et al. (2006) and Jang et al. (2007), who reported that egg quality and egg production are not affected by feeding animals with increasing levels of medicinal plant by-products (1.5% and 3%) or fermented wild ginseng culture by-products (2.5% and 5%). In particular, the authors of these two studies observed that egg production and egg weight significantly increased in treatments containing fermented wild ginseng compared to the controls.

Table 2. Effect of dietary red ginseng marc supplementation on egg production and egg quality in laying hens.

		Treatment				Statistics
Items	Feeding period (days)	Control	T1	T2	T3	SEM	P value
Egg production (%)	15	83.86	85.42	85.66	86.31	2.96	0.9440
	30	83.96	84.74	85.71	84.98	2.23	0.9550
	45	85.00	86.92	87.24	87.56	3.05	0.9459
Egg weight (g)	15	64.34	65.15	65.08	64.00	1.07	0.9617
	30	63.22	63.75	63.79	65.28	1.39	0.8154
	45	61.98	62.15	64.98	63.50	1.84	0.7193
Yolk weight (g)	15	17.16	17.20	16.91	16.68	0.97	0.9791
	30	16.34	16.96	16.43	16.48	0.89	0.9714
	45	16.87	16.96	17.43	18.11	0.78	0.3165
Albumen weight (g)	15	39.28	40.09	40.72	41.33	0.87	0.4991
	30	37.54^b	39.50^b	38.30^b	42.00^a	0.86	0.0102
	45	34.46^b	35.65^ab	36.81^ab	41.48^a	1.80	0.0462
Eggshell weight (g)	15	7.14	7.67	8.23	7.76	0.30	0.2549
	30	7.68	7.95	9.21	8.69	0.45	0.1722
	45	8.11^b	8.10^b	9.29^a	7.89^b	0.26	0.0261
Albumen height (mm)	15	4.77	5.43	5.20	5.90	1.20	0.9253
	30	5.27	5.43	6.17	5.43	0.69	0.8158
	45	5.37	4.73	6.33	5.70	0.88	0.4845
Yolk colour score	15	9.87	9.77	9.70	10.27	0.35	0.7049
	30	9.53	10.07	9.93	10.07	0.38	0.7904
	45	9.87	9.93	10.13	9.87	0.19	0.7487
Eggshell thickness (mm)	15	0.38	0.37	0.36	0.36	0.02	0.7878
	30	0.37	0.36	0.36	0.35	0.02	0.9876
	45	0.38	0.36	0.38	0.38	0.02	0.8857
Eggshell breaking strength (kg/cm^2)	15	3.05	3.60	2.98	3.42	0.25	0.3317
	30	3.33	3.89	3.14	3.41	0.21	0.2448
	45	3.42	3.72	3.36	3.45	0.24	0.7749

Note: Means in the same row with different superscript letters differ significantly (P ≤ 0.05). Data are means ± standard error.

Control, Basal diet; T1, Basal diet + 0.5% red ginseng marc powder; T2, Basal diet + 1% red ginseng powder; T3, Basal diet + 2% red ginseng powder.

In addition, the addition of red ginseng marc had no significant effect on albumin height, yolk colour score, eggshell thickness or eggshell breaking strength as feeding periods increased (Table 2). Similar to the present study, Kim et al. (2006) and Ao et al. (2011a) reported that yolk colour, egg thickness and egg strength are not affected by the supplementation level of medicinal plant by-products (1.5% and 3%) or fermented red ginseng extract (1, 2 and 4 g/kg). However, Jang et al. (2007) observed that treatments with 2.5% and 5% fermented wild ginseng culture by-product could improve egg production compared to the controls. These authors pointed out that an increase in egg production might enhance the health status of laying hens that are fed diets containing ginseng. The different results obtained by various studies have been attributed to differences in ginseng sources or the methods of preparing the ginseng and strains, as reported by Ao et al. (2011a). To the best of our knowledge, there is a paucity of literature available about the effect of red ginseng marc on the egg quality or egg characteristics of hens.

Serum cholesterol and blood profiles

Compared to the controls, increasing levels of red ginseng marc (0.5%, 1% and 2%) showed a reduction in total cholesterol and triglyceride levels or an increase in HDL-C levels (P ≤ 0.05, Table 3). However, there was no significant difference in LDL-C levels among all treatments. Likewise, at 30 and 45 days, total cholesterol was not influenced by dietary treatment with red ginseng marc. As feeding periods increased, triglyceride levels became statistically significant for supplementation with increasing levels of red ginseng marc (T1–T3) compared to the controls; however, all treatments red ginseng marc showed no significant difference in serum cholesterol levels. These results are inconsistent with those of Jang et al. (2007), who reported that fermented wild ginseng culture by-products (2.5% and 5%) had no effect on blood cholesterol in laying hens. In contrast, supplementing laying hens' diets with karaya saponin for 8 weeks did reduce serum cholesterol (23%) and triglycerides, but also increased HDL-C levels compared to the controls, which is consistent with prior studies (Afrose et al. 2010).

Table 3. Effect of dietary red ginseng marc supplementation on serum cholesterol and blood profiles in laying hens.

		Treatment				Statistics
Items	Feeding period (days)	Control	T1	T2	T3	SEM	P value
Total-C (mg/dL)	15	158.33^a	134.00^ab	131.66^ab	123.00^b	7.66	0.0442
	30	134.24	120.00	121.36	116.57	5.18	0.1940
	45	121.36	117.72	112.21	107.00	5.89	0.4139
HDL-C (mg/dL)	15	8.10^b	10.40^b	10.54^b	13.83^a	0.86	0.0146
	30	8.97^b	10.50^b	10.47^b	13.50^a	0.55	0.0047
	45	7.87^b	10.43^ab	11.57^a	13.53^a	0.98	0.0261
LDL-C (mg/dL)	15	36.33	33.21	37.72	35.39	2.29	0.7015
	30	33.67	36.25	35.78	34.66	3.18	0.9619
	45	34.45	33.70	34.55	33.00	2.37	0.9622
Triglyceride (mg/dL)	15	1923.34^a	1614.00^a	1148.35^b	1115.00^b	100.37	0.0029
	30	1357.00^a	1220.00^ab	1165.00^b	1048.67^b	51.24	0.0234
	45	1216.70^a	1089.73^ab	1170.00^ab	1013.43^b	44.29	0.0498
WBC (10^3/mm^3)	15	389.99	396.35	401.35	405.17	8.41	0.2215
	30	393.87	401.37	404.53	412.19	6.36	0.3339
	45	396.87	413.95	412.71	426.22	7.47	0.4131
RBC (10^6/mm^3)	15	2.16	2.30	2.42	2.73	0.18	0.2517
	30	2.11^b	2.18^b	2.33^ab	2.76^a	0.13	0.0452
	45	2.16^b	2.24^b	2.40^b	2.71^a	0.10	0.0069
Haemoglobin (g/dL)	15	7.80	8.57	8.57	9.10	0.61	0.6123
	30	7.93	8.27	8.57	8.83	0.41	0.5189
	45	7.53	7.70	7.97	8.23	0.39	0.6475
Hematocrit (%)	15	27.80	26.97	26.00	26.70	1.98	0.9519
	30	28.50	25.90	28.33	26.63	1.24	0.4665
	45	27.90	26.43	28.57	27.63	0.89	0.4915

Note: Means in the same row with different superscript letters differ significantly (P ≤ 0.05). Data are means ± standard error.

Control, Basal diet; T1, Basal diet + 0.5% red ginseng marc powder; T2, Basal diet + 1% red ginseng powder; T3, Basal diet + 2% red ginseng powder; Total-C, total cholesterol; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; WBC, white blood cell; RBC, red blood cell.

In the current study, the observed reduction in serum cholesterol when red ginseng marc was supplemented to the diet might be caused by the inhibition of cholesterol and/or bile acid absorption (Oakenfull & Sidhu 1990). In general, saponins in red ginseng marc are known to exhibit biological activity (Ao et al. 2011a). In addition, Ao et al. (2011b) indicated that the effect of dietary saponins on cholesterol levels might be associated with species, quantity of dietary supplementation, different sources and processing methods.

In terms of blood profiles (Table 3), the supplementation of red ginseng marc to the diet and feeding periods had no significant influence on WBC, RBC, haemoglobin or hematocrit, except for RBC at 30 and 45 days. While saponins (bioactive ingredients) have been found to have a positive effect on the immune system (Ilsley et al. 2005), immune effects were not confirmed in this study, which were expected to be affected by differences among the low, medium and high supplementation rates. However, Hong et al. (2002) reported that adding germanium colloid (0.5 and 1 ppm) to diets tended to increase WBC and RBC counts or hematocrit concentration in blood, thus improving the immune status of laying hens. Therefore, the immune function may be influenced, whereby WBC and RBC counts or haemoglobin tend to be higher in treatments with different levels of red ginseng marc compared to the control (Hong et al. 2002).

Consequently, despite the fact that saponins are known to exhibit biological activity, there is little direct evidence supporting the beneficial role of red ginseng marc on the egg quality of hens. In this study, the analysis of serum cholesterol and blood profiles showed that the red ginseng marc resulted is advantageous in reducing total cholesterol and triglyceride levels, as well as increasing HDL-C levels (but not LDL-C). Overall, supplementing 1% or 2% red ginseng marc to hen diets might be potentially used as a new antibiotic replacement to decrease serum cholesterol levels in laying hen's diets.

Additional information

Funding

This work was supported by the Small and Medium Business Administration funded by the Korean Government [grant number C0150527]. The authors would like to thank them for their financial support.