Addition of increasing doses of ricinoleic acid from castor oil (Ricinus communis L.) in horse diets: intake, digestibility, glucose and insulin dynamic

Figures & data

Table 1. Chemical composition of forage, concentrate and basal diet (% DM, otherwise stated).

Item	Coast cross hay	Concentrate mixture	Diet
Dry matter (% wet basis)	88.02	89.01	88.52
Organic matter	87.24	93.48	90.36
Crude protein	9.51	16.58	13.05
Neutral detergent fiber	74.08	37.61	55.85
Acid detergent fiber	35.32	10.15	22.74
Ether extract	1.50	10.15	5.83
Starch	1.54	10.54	6.04
Ash	6.57	12.79	9.68
Calcium	0.07	0.78	0.43
Phosphorus	0.15	0.18	0.17

Table 2. Effects of increasing doses (g/d) of ricinoleic acid on nutrient intake of horses.

	Diet^a				SEM	P-value
Item	0	1	2	3		Diet	L	Q
kg/d
Ration	8.51	8.72	8.68	8.89	0.03	0.645	0.654	0.132
Hay	4.12	4.50	4.45	4.65	0.04	0.314	0.651	0.111
Concentrate	8.51	8.72	8.68	8.89	0.01	0.458	0.872	0.643
kg/d
Dry matter	7.33	7.72	7.68	7.97	0.02	0.145	0.338	0.654
Organic matter	6.81	6.97	6.94	7.11	0.02	0.675	0.331	0.321
Neutral detergent fiber	4.21	4.31	4.29	4.40	0.01	0.674	0.641	0.984
Acid detergent fiber	1.71	1.76	1.75	1.79	0.01	0.986	0.321	0.355
Crude protein	0.98	1.01	1.00	1.03	0.05	0.231	0.611	0.766
Ether extract	0.44	0.45	0.45	0.46	0.04	0.613	0.245	0.761
Starch	0.45	0.47	0.46	0.48	0.07	0.766	0.543	0.209
Ash	0.73	0.75	0.74	0.76	0.03	0.533	0.776	0.659
g/d
Calcium	32.39	33.19	33.04	33.84	0.01	0.654	0.321	0.543
Phosphorous	12.81	13.12	13.06	13.38	0.01	0.542	0.543	0.198

Notes: Linear (L) or quadratic (Q) effects. SEM: standard error of the mean.

^aAddition of 0, 1, 2 or 3 g of ricinoleic acid in diet (DM basis).

Table 3. Effects of increasing doses (g/d) of ricinoleic acid on nutrient total tract digestion of horses (% DM).

	Diet^a				SEM	P-value
Item	0	1	2	3		Diet	L	Q
Dry matter	58.20	57.83	60.00	59.96	0.99	0.771	0.382	0.931
Organic matter	58.76	58.93	61.03	62.56	0.01	0.195	0.763	0.153
Crude protein	73.58	77.00	79.08	78.63	0.69	0.414	0.219	0.266
Fat	81.68	79.96	80.40	81.38	0.69	0.653	0.925	0.231
Neutral detergent fiber	57.43	51.22	53.93	52.11	1.64	0.572	0.385	0.518
Acid detergent fiber	37.32	37.73	40.40	37.83	1.65	0.932	0.791	0.676
Starch	86.69	83.97	87.95	85.65	0.07	0.256	0.831	0.054

Notes: Linear (L) or quadratic (Q) effects. SEM: standard error of the mean.

^aAddition of 0, 1, 2 or 3 g of ricinoleic acid in diet (DM basis).

Figure 1. Glucose blood concentrations of horses fed with increasing doses of ricinoleic acid according to the morning feeding time (mean ± SD).

Figure 2. Insulin blood concentration of horses fed with increasing doses of ricinoleic acid according to the morning feeding time (mean ± SD).

Figure 3. Observed and estimated values of the regression equation of area under the curve (AUC) of blood glucose concentrations of horses according to ricinoleic acid dose.

Figure 4. Observed and estimated values of the regression equation of area under the curve (AUC) of blood insulin concentrations of horses according to ricinoleic acid dose.

Table 4. Effects of increasing doses (g/d) of ricinoleic acid on blood glucose and insulin dynamic of horses.

	Diet^a				SEM	P-value
Item	0	1	2	3		Diet	L	Q
Glucose (mg/dL × min)	512.88	423.75	429.25	453.97	19.05	0.023	0.251	0.043
Insulin (µUI/mL × min)	33.12	35.31	51.37	42.93	3.04	0.011	0.014	0.026
Glucose (mg/dL)	117.06	108.46	127.17	100.17	2.57	0.002	0.057	0.015
Insulin (µUI/mL)	9.17	10.65	11.17	8.87	0.58	0.122	0.916	0.019

Notes: Linear (L) or quadratic (Q) effects. SEM: standard error of the mean.

^aAddition of 0, 1, 2 or 3 g of ricinoleic acid in diet (DM basis).