The effects of oregano essential oil on production performance and intestinal barrier function in growing Hyla rabbits

Figures & data

Table 1. The main components of oregano essential oil in this experiment.

Component	Content, %
Carvacrol	60.00
P-Cymen	5.00
Gamma-Terminen	4.00
Thymol	1.00
Beta-caryophyllen	2.00
Linalool	5.00
Alpha-Terpinen	1.50
Terpinen-4-ol	2.00
Trans-Sabinenhydrate	0.30

Table 2. Composition and nutrient levels of basal diets (air-dry basis).

Item	Content, %	Item	Content
Ingredients		Nutrient level^b
Corn	13.3	DM	84.49
Soybean meal	13	CP	16.24
Wheat bran	19	EE	3.11
Corn Germ	19	CF	15.44
Alfalfa	12	NDF	36.14
Soya	19	ADF	19.11
Bean oil	0.7	Ca	0.42
Premix^a	4	P	0.42
Total	100

DM: dry matter; CP: crude protein; EE: ether extract; CF: crude fibre; NDF: neutral detergent fibre; ADF: acid detergent fibre; Ca: calcium; P: phosphorus.

^aThe premix provided the following per kg of diet: VA 12,000 IU, VD3 9000 IU, VE 50 mg, VK31.5 mg, VB11.5 mg, VB2 25 mg,VB3 40 mg,VB5 50 mg, VB6 0.5 mg, VB11 2.5 mg, VB12 0.02 mg, cholinechloride 600 mg, biotin 0.2 mg, K 7 mg, Mg 3 mg, Fe 60 mg, Zn 60 mg, Cu 40 mg, Mn 9 mg, I 1 mg, Se 0.2 mg, Iimestone 15,000 mg, NaCl 5000 mg, Lys 1000 mg, Met 2000 mg. The rest was miscellaneousmeal carrier complement.

^bNutrient levels were measured values.

Table 3. Gene-specific primers used for the analysis of rabbit gene expression.

Gene	Genebank accession number	Primers sequences (5′→3′)	Product size, bp
β-actin	NM_001101683.1	F:CGCAGAAACGAGACGAGATT	168
		R:GCAGAACTTTGGGGACTTTG
Occludin	XM_008262318	F: CTTGCCTGGGACAGAACCTA	121
		R: AGCCATAACCGTAGCCGTAA
Claudin	NM_001089316.1	F:GGAGCAAAAGATGCGGATGG	93
		R:AATTGACAGGGGTCAAAGGGT
ZO-1	XM_008269782.1	F: GACTGATGCGAAGACGTTGA	117
		R: GCAGAATGGATGCTGTCAGA
ZO-2	XM_017341705.1	F: CAGCAAGGAGAGGCAGTGTG	119
		R: CGGCTGTCGCAACTCAGATA
JAM2	XM_017346699.1	F: ATATCGCAGGTGTCCTGGAA	122
		R: GAGCATAGCACACGCCAAG
JAM3	XM_008248362.2	F: TGTGAGGAGCAGGAGATGGA	123
		R: GCCACGTCTGTATGCACAGC
Muc1	L41544.1	F: TATACCGCAAGCAGCCAGGT	135
		R: GCAAGCAGGACACAGACCAG
Muc4	XM_017347029.1	F:TCCTCCAGTCACCTCAGCAG	121
		R: GCTGGTTGGAGATCCTCTGG

ZO-1: Zonula occludens 1; ZO-2: Zonula occludens 2; JAM2: junctional adhesion molecule 2; JAM3: junctional adhesion molecule 3; Muc1: Mucorprotein 1; Muc4: Mucorprotein4.

Table 4. Effect of oregano essential oil on production performance of rabbits.

Item	Dietary oregano essential oil added levels, %				R-MSE	p-Value
	Control	LO	MO	HO
IBW, g	1266.90	1264.55	1270.91	1274.46	187.93	.9982
FBW, g	2432.86	2510.00	2400.93	2481.96	289.68	.6004
ADG^a, g/d	31.51	33.66	30.54	32.64	6.14	.3673
ADFI^b, g/d	126.67^ab	128.97^a	118.50^ab	115.37^b	18.40	.0474
F/G^c	4.22^a	3.85^ab	4.00^ab	3.61^b	0.85	.1213
Diarrhoea rate, %	43.75	25.00	56.25	31.25	30.78	.0035
Death rate, %	29.17	22.92	25.00	20.83	31.11	.8153

IBW: initial body weight; FBW: final body weight; ADFI: average daily feed intake; ADG: average daily gain.

Oregano essential oil was added at 0.00% in the Control group; 0.02% in the LO group; 0.04% in the MO group; and 0.08% in the HO group.

Means within lines with different superscript letters are significantly different (p < .05).

^aADG = (FBW − IBW)/Test days.

^bADFI = Total feed intake per rabbit during normal feeding/Test days.

^cF/G = ADFI/ADG.

Table 5. Effect of oregano essential oil on slaughter performance of rabbits.

Item	Control	HO	R-MSE	p-Value
Pre-slaughter weight, g	2384.00	2385.56	0.98	.9883
Full-bore weight, g	1100.89	1152.78	156.24	.4913
Half-bore weight, g	1195.56	1242.22	163.72	.5539
Full-bore rate, %	46.03	48.19	2.94	.1385
Half-bore rate, %	50.02	51.94	3.08	.2045

Full-bore rate = Full-bore weight/Pre-slaughter weight.

Half-bore rate = Half-bore weight/Pre-slaughter weight.

Table 6. Effect of oregano essential oil on intestinal morphology of rabbits.

Item	Control	HO	R-MSE	p-Value
Duodenum
Villus high, um	847.33	852.67	82.6542	.9408
Crypt depth, um	184.50	183.00	8.3964	.8375
V/C	4.59	4.68	0.5252	.8384
Jejunum
Villus high, um	756.00	822.37	67.8903	.5627
Crypt depth, um	154.50	186.87	20.7553	.0695
V/C	4.95	4.57	0.709	.4772
Ileum
Villus high, um	526.28	548.67	40.9694	.5399
Crypt depth, um	178.33	133.67	28.175	.1241
V/C	2.96^b	4.25^a	0.5559	.0471

V/C: Villus high/Crypt depth.

Means within lines with different superscript letters are significantly different (P<0.05).

Figure 1. Effect of oregano essential oil on the expression of intestinal barrier related genes [Jejunum (A), Ileum (B)]. ZO-1: zonula occludens 1; ZO-2: zonula occludens 2; JAM2: junctional adhesion molecule 2; JAM3: junctional adhesion molecule 3; Muc1: mucorprotein 1; Muc4: mucorprotein 4. ^a,bMeans with different superscripts are significantly different (p < .05).

Figure 2. Effect of oregano essential oil on intestinal immune barrier [IL-2 (A), IL-10 (B), SIgA (C), SIgG (D), TNF-α (E)]. IL-2: interleukin-2; IL-10: interleukin-10; SIgA: secretory immunoglobulin A; SigG: secretory immunoglobulin G; TNF-α: tumour necrosis factor-α. ^a,bMeans with different superscripts are significantly different (p < 0.05).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.