The nutritional value of flaxseed meal for swine
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The nutritional value of flaxseed meal (FSM), a by-product of the flax crushing industry, has not been evaluated properly for use within swine rations. A series of experiments were conducted to determine the nutritional profile of this novel feed ingredient for pigs.The analysis of FSM revealed that it contains, on a dry matter (DM) basis, 133 g/kg ether extract (EE), 345 g/kg crude protein (CP), 60 g/kg ash, 164 g/kg ADF, 250 g/kg NDF, 102 g/kg crude fibre, 14 g/kg starch and 9 g/kg phosphorus. The gross energy (GE) content of the meal was 5.2 Mcal/kg DM. The ether extract fraction was characterized by, as a percent of total fat, 46.6% á-linolenic acid, an omega-3 fatty acid. Palmitic, stearic, oleic and linoleic acids accounted for 9.5, 4.8, 20.7 and 18.4% of the total fat content respectively. The crude protein content was well balanced for all amino acids with the exception of lysine (4.1% of CP), the level of which falls below that of the requirements for growing pigs (5.3% of CP for pigs 20-50 kg). The apparent digestibility of DM, nitrogen, ash, EE and GE as well as determination of the DE and NE content of FSM was determined for both growing pigs (32 pigs, initial weight 70 ± 3 kg) and gestating sows (26 pigs, parities 2 – 4). Animals were fed wheat/barley based diets containing 0, 10, 20 or 30% FSM. Faecal grab samples were collected for 3 days after a dietary adaptation period. The apparent digestibility of nutrients in FSM was determined both by regression and by difference calculations. As calculated by difference, the apparent digestibility coefficients for DM, nitrogen, ash, and GE were 63.0, 60.8, 22.3 and 60.5% respectively for growing pigs. The values obtained for sows were 64.1, 58.8, 20.8, 94.9 and 65.4% for DM, nitrogen, ash, EE and GE respectively. The DE content was 3.37 Mcal/kg for growing pigs and 3.52 Mcal/kg for sows. Net energy was then estimated by use of a prediction equation to be 2.34 and 2.44 Mcal/kg for growing pigs and sows. An experiment was conducted to evaluate the growth performances and carcass fatty acid profiles of pigs fed with graded levels of FSM. A total of 200 pigs (100 barrows, 100 gilts; initial weight 32 ± 4 kg) were blocked by gender and housed in groups of 5 pigs per pen. The experiment was divided into three phases for pigs 32-60 kg, 60-85 kg and 85-115 kg. Each group was assigned to one of four dietary treatments containing 0, 5, 10 or 15% FSM at the expense of wheat and soybean meal. At the time of market, 6 pigs per treatment group were randomly selected for carcass fatty acid analysis, and backfat and rib-end loin samples were collected. The average daily gains, average daily feed intakes and gain to feed ratios were not affected by dietary treatment (P > 0.05). Inclusion of 15% dietary FSM increased the ALA content from 11 to 47 (± 0.8) mg/g of backfat (P < 0.001) and from 5 to 10 (± 0.4) mg/g of loin tissue (P < 0.001). Increasing dietary FSM decreased the saturated fatty acid content of backfat (P < 0.01). The final experiment was designed to determine the availability of phosphorus in semi-synthetic diets containing FSM, and to determine the effects of microbial phytase inclusion of this availability. Five treatment groups, 8 barrows (45 ± 4 kg initial weight) each, were fed a diet containing 30% FSM with increasing levels of phytase (0, 575, 1185, 2400 and 2570 FTU/kg). Apparent P digestibility increased from 20.6 to 61.3% with the inclusion of up to 2570 FTU/kg microbial phytase (P < 0.001), and followed a quadratic response pattern with an R2 value of 0.96. A broken-line analysis estimated the optimal phytase inclusion level to be 1415 FTU/kg of diet. Inclusion of just 575 FTU/kg accounted for half of the response, improving the apparent P digestibility by 20% and reducing P excretion by 850 mg/kg dry matter intake.
DegreeMaster of Science (M.Sc.)
DepartmentAnimal and Poultry Science
ProgramAnimal and Poultry Science
CommitteeShand, Phyllis J.; Patience, John F.; Drew, Murray D.; Van Kessel, Andrew G.
omega-3 fatty acid