Flaxseed Meal in Swine Rations: Standardised Ileal Amino Acid Digestibility

Flaxseed meal (FSM) is a good source of dietary protein for hogs, and comparable to that of canola meal in terms of both quantity and quality (Standard Ileal Digestibility values), according to L. Eastwood and P. Leterme in the 2008 Annual Research Report from Prairie Swine Centre.
calendar icon 15 June 2010
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Pascal Leterme


Flaxseed meal (FSM) is a good source of dietary protein for hogs, containing 34 per cent crude protein (CP). With the exception of a characteristic low lysine content (3.6 per cent of CP), the CP fraction of FSM is comparable to that of canola meal in terms of both quantity and quality (Standard Ileal Digestibility values), making it an attractive alternative to conventional protein sources.


Recently, there has been a growing interest in the use of flaxseed and its related products such as FSM within the swine industry. Flaxseed meal is a by-product of the flaxseed crushing industry, and depending on the oil extraction process used, the meal may contain up to 12 per cent oil with 34 per cent CP. Prior to the routine acceptance and inclusion of FSM by the pork industry, a full nutritional profile must be made available to producers and nutritionists. A major component of this nutritional profile includes the apparent (AID) and standardized ileal amino acid digestibility (SID) content of the meal.

Flaxseed meal is an attractive alternative to conventional protein sources

Material and Methods

This experiment used a total of five growing barrows (38kg initial weight) fitted with T-cannulas at the terminal ileum. The pigs were housed in metabolism pens, and following a seven-day recovery period from surgery, were fed a semi-synthetic diet containing 40 per cent FSM. Feeding of the test diet lasted for seven days, including a 4 day adaptation period followed by 3 days of digesta collection. Following this, the pigs were then fed a nitrogen-free diet for a similar time period in order to correct the digestibility calculations for basal endogenous losses. Chromic oxide was included in both diets as an indigestible marker.

Results and Discussion

Table 1 shows the apparent and standardised ileal amino acid digestibilities for FSM, along with the quantity of AID and SID amino acids found in FSM. The AID digestibility values ranged from 25.1 to 86.1 per cent on a DM basis, whereas SID values ranged from 67.6 to 93.8 per cent. The digestibilities of threonine and cysteine are both low, with the AID values falling below 60 per cent and the SID values at 73 per cent; however, many of the amino acids are over 80 per cent digestible.


Flaxseed meal contains 34 per cent CP and also contains appreciable amounts of many of the essential amino acids. The SID coefficients for the essential amino acids range from 67 to 94 per cent, which aff ects the overall protein quality of the product; however, the amounts of SID essential amino acids in FSM are very similar to those reported for canola meal (NRC, 1998). Flaxseed meal is characterized by a low lysine content (3.6 per cent of CP) in comparison to other meal products and when compared to the requirements of the pig (5.3 per cent of CP for pigs 25 to 50 kg), and will likely be the limiting factor for the dietary inclusion of FSM into swine rations. This is also confounded by the fact that FSM has a low Lysine digestibility (74 per cent). It will be critical to consider this low Lysine content and digestibility when formulating rations to ensure the requirements of the animals are met.

June 2010

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