The role of dietary monoglycerides and tributyrin in enhancing performance and intestinal health function in nursery piglets

Figures & data

Table 1. Composition of dietary treatments offered to nursery piglets (as-fed)^a.

Ingredients	Pre-stater				Starter
	NC	PC	MGD	TBT	NC	PC	MGD	TBT
Ground corn, 7.8% crude protein (CP)	47.77	47.74	47.58	47.51	59.93	60.01	59.85	59.99
Soybean meal, 45.4% CP	20.84	20.85	20.87	20.89	24.72	24.77	24.80	24.90
Dry whey, 12.8% CP	9.99	9.99	9.99	9.99
Semi-extruded soybean, 43.1% CP	7.99	7.99	7.99	7.99	5.99	6.00	6.00	5.58
Sugar	3.99	3.99	3.99	3.99
Fish meal, 53.0% CP	2.99	2.99	2.99	2.99	2.99	3.00	3.00	3.01
Soybean oil	2.21	2.22	2.17	2.23	2.29	2.30	2.25	2.32
Dicalcium phosphate	1.31	1.31	1.31	1.31	1.43	1.43	1.43	1.44
Calcitic limestone	0.78	0.78	0.78	0.78	0.72	0.72	0.72	0.73
Lysine sulphate, 54.6%	0.65	0.65	0.65	0.65	0.53	0.53	0.53	0.53
DL-methionine, 99.5%	0.21	0.21	0.21	0.21	0.16	0.16	0.16	0.17
L-threonine, 96.8%	0.25	0.25	0.25	0.25	0.18	0.18	0.18	0.18
L-tryptophan, 99%	0.04	0.04	0.04	0.04	0.02	0.02	0.02	0.02
L-valine, 95.5%	0.32	0.32	0.32	0.32	0.15	0.15	0.15	0.16
Premix^b	0.29	0.29	0.29	0.29	0.29	0.30	0.30	0.30
Sodium chloride	0.20	0.20	0.20	0.20	0.42	0.42	0.42	0.42
Halquinol 60%	–	0.01	–	–	–	0.01	–	–
Monoglycerides blend	–	–	0.20	–	–	–	0.20	–
Tributyrin	–	–	–	0.20	–	–	–	0.20

^aDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^bComposition per kg diet: Mn sulphate, 60 mg; Zn oxide, 80 mg; Fe sulphate, 60 mg; copper sulphate, 10 mg; iodine, 1 mg; sodium selenite, 0.6 mg; vitamin K₃, 2.56 mg; vitamin B₁, 1.28 mg; vitamin B₂, 3.2 mg; vitamin B₆, 1.28 mg; niacin, 19.65 mg; pantothenic acid, 6.46 mg; folic acid, 0.38 mg; vitamin B₁₂, 0.01 mg; biotin, 0.12 mg; vitamin A, 6400 IU; vitamin D₃, 1280 IU; vitamin E, 16 IU.

Table 2. Calculated and analysed chemical composition of diets offered to nursery piglets (as-fed).

  

Item	Pre-stater				Starter
	NC	PC	MGD	TBT	NC	PC	MGD	TBT
Calculated chemical composition
Metabolisable energy (MJ/kg)	14.130	14.130	14.130	14.130	14.020	14.020	14.020	14.020
Crude protein (%)	19.870	19.870	19.870	19.870	20.550	20.550	20.550	20.550
Lactose (%)	7.000	7.000	7.000	7.000	–	–	–	–
Standardised ileal digestible (SID) lysine (%)	1.346	1.346	1.346	1.346	1.281	1.281	1.281	1.281
SID methionine + cysteine (%)	0.754	0.754	0.754	0.754	0.730	0.730	0.730	0.730
SID threonine (%)	0.902	0.902	0.902	0.902	0.833	0.833	0.833	0.833
SID tryptophan (%)	0.256	0.256	0.256	0.256	0.243	0.243	0.243	0.243
SID valine (%)	0.929	0.929	0.929	0.929	0.884	0.884	0.884	0.884
Total sodium (%)	0.219	0.219	0.219	0.219	0.205	0.205	0.205	0.205
Total calcium (%)	0.973	0.973	0.973	0.973	0.910	0.910	0.910	0.910
Standardised total tract digestible phosphorus (%)	0.481	0.481	0.481	0.481	0.450	0.450	0.450	0.450
Analysed chemical composition
Gross energy (MJ/kg)	17.430	17.480	17.400	17.370	17.500	17.500	17.420	17.500
Crude protein (%)	19.290	20.040	20.240	19.480	20.040	20.180	21.060	20.480
Dry matter (%)	89.140	88.350	88.850	88.500	88.630	87.270	88.670	88.160
Neutral detergent fibre (%)	11.620	12.600	11.760	11.860	11.900	11.010	11.960	12.830
Acid detergent fibre (%)	3.880	3.280	3.200	3.230	3.520	3.430	3.050	3.380
Crude fibre content (%)	2.250	2.250	2.250	2.250	2.550	2.550	2.550	2.540
Ether extract (%)	6.890	6.940	7.000	6.340	6.410	6.800	7.590	7.400

SID: standardised ileal digestibility.

Table 3. Growth performance and diarrhoea occurrence (DO) in nursery piglets fed monoglycerides blend and tributyrin^d.

Item^g	Treatments^e				SEM^f	p-value
	NC	PC	MGD	TBT
Pre-starter (day 0–20)
FBW, kg	14.820	14.650	13.880	13.720	0.313	.373
ADFI, kg	0.480	0.450	0.420	0.410	0.017	.511
ADG, kg	0.330	0.320	0.290	0.280	0.011	.292
F:G, kg:kg	1.470	1.380	1.410	1.490	0.024	.407
DO, %^h	12.500^a	3.570^c	10.710^a,b	4.460^b,c	0.024	.022
Starter (day 20–35)
FBW, kg	24.620	24.230	23.140	22.880	0.387	.213
ADFI, kg	1.060	1.000	0.990	0.980	0.019	.650
ADG, kg	0.690	0.650	0.650	0.640	0.012	.317
F:G, kg:kg	1.510	1.540	1.550	1.520	0.017	.689
DO, %^h	7.140^a	0.000^b	0.000^b	1.790^b	0.008	<.001
Overall period (day 0–35)
ADFI, kg	0.690	0.670	0.650	0.640	0.012	.639
ADG, kg	0.470	0.460	0.440	0.430	0.008	.474
F:G, kg:kg	1.480	1.440	1.490	1.480	0.023	.920

^a–b–cObserved proportions followed by different lowercase letters within the same row differ using a test of the difference between the lsmeans, through the χ² statistic (p < .05).

^dData are averages of 8 pen replicates per treatment and 3 animals per pen as experimental unit.

^eDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^fSEM: pooled standard error of the mean.

^gIBW: initial body weight; FBW: final body weight; ADFI: average daily feed intake; ADG: average daily gain; F:G: feed to gain ratio.

^hDO (%) = dividing the sum of DO by the total number of observations in each treatment and then multiplying by 100%.

Table 4. Blood metabolites profile in nursery piglets fed monoglycerides blend and tributyrin^c.

Item^f	Treatments^d				SEM^e	p-value
	NC	PC	MGD	TBT
Pre-starter (day 0–20)
Total protein (g/dL)	4.570	5.150	5.220	4.800	0.119	.178
Albumin (g/dL)	3.320	3.130	3.090	3.030	0.100	.343
Total cholesterol (mg/dL)	78.420	75.380	85.150	77.840	3.163	.656
Alkaline phosphatase (U/L)	386.520^a,b	455.270^a	398.130^a,b	307.290^b	19.193	.038
AST (U/L)	50.310^a,b	62.040^a	65.030^a	36.970^b	5.876	.037
ALT (U/L)	46.900	52.220	48.260	45.690	2.759	.851
Glucose (mg/dL)	105.180	106.920	99.640	106.280	1.870	.172
Urea (mg/dL)	17.180	16.950	21.140	19.170	0.769	.162
Starter (day 20–35)
Total protein (g/dL)	4.470	4.730	4.750	4.690	0.098	.672
Albumin (g/dL)	3.300	3.170	3.150	3.240	0.127	.842
Total cholesterol (mg/dL)	97.150	95.080	94.390	101.740	2.424	.685
Alkaline phosphatase (U/L)	411.400	422.030	404.410	319.270	21.263	.197
AST (U/L)	82.180	77.770	90.930	84.370	3.862	.630
ALT (U/L)	72.410	68.260	67.810	78.260	3.798	.641
Glucose (mg/dL)	108.970	105.800	100.990	100.650	1.587	.205
Urea (mg/dL)	16.530^b	18.700^a,b	21.040^a	15.810^b	5.335	.012

^a–bAverages followed by different lowercase letters within the same row differ by the Tukey’s test (p < .05).

^cData are averages of 16 piglets per treatment.

^dDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^eSEM: pooled standard error of the mean.

^fAST: aspartate aminotransferase; ALT: alanine aminotransferase.

Table 5. Weight of relative digestive and non-digestive organs (expressed as a percentage of body weight) and gastrointestinal tract contents pH in nursery piglets fed monoglycerides blend and tributyrin at day 35^a.

Item	Treatments^b				SEM^c	p-value
	NC	PC	MGD	TBT
Weight of relative organs (%)
Heart	0.550	0.500	0.530	0.530	0.011	.480
Empty stomach	0.790	0.810	0.810	0.750	0.018	.752
Empty small intestine	4.170	3.910	3.960	4.260	0.106	.616
Empty caecum	0.240	0.210	0.240	0.200	0.008	.191
Empty colon	1.830	2.000	1.900	1.830	0.037	.390
Liver with gallbladder	2.630	2.580	2.580	2.600	0.035	.886
Spleen	0.200	0.210	0.200	0.220	0.007	.815
Kidneys	0.490	0.520	0.510	0.500	0.009	.809
Empty small intestine (%)	56.080	56.150	55.860	56.130	0.192	.992
Small intestine (m)	13.330	13.390	13.100	13.300	0.720	.874
pH
Stomach	4.040	4.610	3.380	4.310	0.232	.152
Jejunum	6.010	6.170	5.790	5.670	0.098	.328
Ileum	6.030	5.760	5.890	5.800	0.140	.914
Caecum	5.270	5.350	5.370	5.340	0.033	.759
Colon	5.690	5.780	5.800	5.900	0.045	.427

^aData are averages of 6 piglets per treatment.

^bDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^cSEM: pooled standard error of the mean.

Table 6. Villous height (VH), crypt depth (CD) and VH:CD ratio of the jejunum and ileum in piglets fed monoglycerides blend and tributyrin at day 35^c.

Item	Treatments^d				SEM^e	p-value
	NC	PC	MGD	TBT
Jejunum
VH (μm)	420	480	440	415	16.800	.529
CD (μm)	180	170	160	153	7.100	.601
VH:CD ratio	2.260^b	2.940^b	2.990^b	3.820^a	0.153	.004
Ileum
VH (μm)	353	320	390	383	11.600	.176
CD (μm)	216	173	186	213	7.300	.099
VH:CD ratio	1.710	1.900	2.200	2.010	0.077	.121

^a–bAverages followed by different lowercase letters within the same row differ by the Tukey’s test (p < .05).

^cData are averages of 6 piglets per treatment.

^dDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^eSEM: pooled standard error of the mean.

Figure 1. Cell infiltrate of the ileum in piglets fed monoglycerides blend and tributyrin at day 35 (n = 6 piglets per treatment). dietary treatments: (A) negative control: diet without feed additive or antimicrobial growth promoters; (B) positive control: diet containing 60 mg halquinol/kg diet; (C) diet containing 2 g monoglyceride blend/kg diet (MGD); and (D) diet containing 2 g tributyrin/kg diet (TBT). the monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

Table 7. Intestinal histopathology of the jejunum and ileum in piglets fed monoglycerides blend and tributyrin at day 35^c.

Item	Treatments^d				SEM^e	p-value
	NC	PC	MGD	TBT
Jejunum
Cell infiltrate	1.490	1.780	1.410	1.160	0.207	.351
Congestion	1.150	1.030	1.150	1.400	0.101	.116
Epithelial desquamation	1.480	1.990	1.290	1.330	0.283	.461
Ileum
Cell infiltrate	1.490^a,b	1.000^b	1.800^a	1.390^a,b	0.175	.025
Congestion	1.620	1.150	1.500	1.150	0.146	.068
Epithelial desquamation	1.680	1.250	1.580	1.340	0.209	.418

^a–bAverage scores followed by different lowercase letters on the same row differ using a test of the difference between the lsmeans, through the χ² statistic (p < .05). Histopathological description: 0 = absent; 1 = discrete; 2 = moderate; 3 = intense.

^cData are averages of 6 piglets per treatment.

^dDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

^eSEM: pooled standard error of the mean.

Table 8. Bacterial counts (log₁₀ CFU/g) in the jejunum content of piglets fed monoglycerides blend and tributyrin at day 35^c.

Item	Treatments^d				SEM^e	p-value
	NC	PC	MGD	TBT
Clostridium sulfite-reducer	4.370	4.040	2.820	2.980	0.377	.431
Enterobacteriaceae	6.780^a	7.010^a	4.670^b	7.360^a	0.292	.002
Lactic acid bacteria	8.600	8.100	8.090	8.210	0.154	.641

^a–bAverages followed by different lowercase letters within the same row differ by the Tukey’s test (p < .05).

^cData are averages of 6 piglets per treatment.

^dDietary treatments: (1) negative control (NC): diet without feed additive or antimicrobial growth promoters; (2) positive control (PC): diet containing 60 mg halquinol/kg diet; (3) diet containing 2 g monoglyceride blend/kg diet (MGD); and (4) diet containing 2 g tributyrin/kg diet (TBT). The monoglyceride blend contained 33% monolaurate and 41.3% C8 and C10 monoglycerides. The tributyrin contained 55.8% tributyrin and silica (excipient).

³SEM: pooled standard error of the mean.

Data availability statement

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