High-Oil Oat Groats for Weaned Pigs

Report of a study by Pascal Leterme, Brian Rossnagel and John F. Patience (Prairie Swine Centre, Canada).

11 September 2008

6 minute read

Summary

The interest for weaned pigs of oat groats with high oil content (HOOG) was evaluated. The groats contained 95g oil, 159g crude protein and 3,724 kcal digestible energy (DE)/kg DM. Weaned pigs fed for 4 weeks (7 to 22 kg) with diets containing graded levels (0, 15, 30 or 45%) of oat groats, incorporated at the expense of wheat and soybean meal (85%-15%), presented average daily gains similar to those obtained with wheat. In conclusion, high-oil oat groats can replace wheat in diets for weaned pigs.

Introduction

After weaning, young pigs need highly palatable, digestible diets, devoid of antinutritional factors and with high digestible energy (DE) content. Feed ingredients corresponding to that description are generally expensive and choice is quite limited.

One alternative could be oat groats (dehulled oats) with high oil content. Oat groats are well consumed and digested by young pigs and have the highest lysine content among all the cereal species used in swine nutrition (Van Barneveld et al., 1998). They can substitute corn or wheat in weaned pig diets without any risk of adverse effect (Christison and Bell, 1980). The DE content of oat groats is not higher than that of wheat or corn.

Dr B. Rossnagel from the Crop Development Centre of the University of Sakatchewan has recently developed new oat varieties with high oil content (> 9% DM) that could become an interesting feed ingredient for weaned pigs, thanks to their presumed high DE content, if their nutritional advantage is confirmed. The present project aimed at determining the nutritional value of high-oil oat groats (HOOG) and their effect on the growth performances of weaned pigs.

Material and Methods

High-oil oats were grown at the Crop Development Centre and then processed with an oat dehuller. They were ground by means of a hammer mill (9/64”). For the digestibility study, a diet composed of oats (94.6%), a mineral/vitamin premix (5%) and an indigestible marker (chromic oxide, 0.4%) was prepared. After adaptation to the diet, the faeces were collected for 3 days and, 4 hours after the last meal, the pigs were killed and their ileum content was collected and analysed for dry matter, nitrogen, amino acids and acid-insoluble ash. For the growth study, four diets containing 0, 15, 30 or 45% oat groats, were prepared (Table 1). 192 weaned pigs, divided in groups of 4 pigs (2 male, 2 female), were fed one of the 4 experimental diets (48 pigs/diet) for 4 weeks (starting 1 week after weaning). They were weighed weekly and feed intake was recorded.

Ingredient	0%	15%	30%	45%
Table 1. Composition of experimental diets (g/kg)
Wheat	630	504	379	253
HOOG	0	150	300	450
SBM	160	150	140	130
Fish meal/whey	20/35	20/35	20/35	20/35
Canola oil	44	31	17	4
Minerals/vitamins	33	33	33	33
Lysine78%	1.4	1.2	1.0	0.8
Threonine	0.8	0.6	0.5	0.3
Methionine	0.9	0.6	0.3	-\|

DE (Mcal/kg)	3.61	3.63	3.65	3.67
NE (Mcal/kg)	2.35	2.35	2.35	2.35
CP (g/kg)	220	222	224	225
SID Lys (g/kg)	11.1	11.1	11.1	11.1
SID Thr (g/kg)	6.6	6.6	6.6	6.6
SID SAA (g/kg)	6.3	6.3	6.3	6.6
SID Trp (g/kg)	2.1	2.1	2.1	2.2
Ca (g/kg)	8.0	8.0	8.0	8.0
Av. P (g/kg)	4.0	4.0	4.0	4.0

Results and Discussion

Chemical composition, ileal AA digestibility and DE content
The composition of the oat groats was as follows: 90% dry matter and, in g/kg DM: 145g crude protein, 95g oil, 98g NDF, 28g ADF, 64g ash, 6.3g lysine, 2.2g methionine (6.2g S-containing AA) and 4.9g threonine. The ileal digestibility of nitrogen, lysine, methionine, cysteine and threonine was, respectively, 80, 77, 85, 81 and 77%. The DE content was 3,712 kcal/kg DM.

As compared to wheat, HOOG has a higher lysine content (4.3% of the protein vs 3.9% on average for wheat). On the contrary, the DE content is lower than that of wheat (± 3,900 kcal DE/kg DM), despite the higher oil content. This can probably be explained by the low oil digestibility of the HOOG: ± 20% only. The grinding was probably not fine enough to allow the release of the drops of oil entrapped within the cell walls.

Growth study
The results of growth performances obtained by the weaned pigs fed with graded levels of HOOG are detailed in Table 2. No significant effect was observed between treatments for the whole period. Average daily feed intakes (ADFI) and feed conversion ratios (FCR) were not affected either. Thus, HOOG are well ingested by weaned pigs. It must be pointed out here that HOOG mainly replaced wheat but also some soybean meal (Table 1). It is thus possible to take advantage of the high protein content and the relatively good quality of the oat proteins. An advantage of HOOG over wheat was expected, since the former contains more oil and is supposed to have a higher energy value. As explained above, this is probably to be ascribed to the low oil digestibility.

% HOOG	0%	15%	30%	45%
Table 2. Growth performance of weaned pigs fed with graded levels of HOOG
WEEK 1
ADG (g)	288	254	295	273
ADFI (g)	359	320	353	329
Feed conversion	1.26	1.29	1.20	1.20
WEEK 2
ADG (g)	430	431	406	443
ADFI (g)	577	496	529	541
Feed conversion	1.34	1.21	1.31	1.22
WEEK 3
ADG (g)	606	617	618	715
ADFI (g)	789	780	815	816
Feed conversion	1.30	1.26	1.23	1.14
WEEK 4
ADG (g)	736	730	715	723
ADFI (g)	1,055	1,031	1,033	1,050
Feed conversion	1.43	1.41	1.44	1.46

Implication

HOOG did not present any advantage in the diet of weaned pigs, as compared to wheat. The reason could be the low oil digestibility, explained by an inadequate grinding. Further research is required to find the conditions for an optimal use of HOOG in weaned pig nutrition.