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Determination of protein and amino acid digestibility of microbially-converted soybean meal in comparison to fish meal
Fish meal (FM) is included in weaned pig diets as a high quality, easily digestible ingredient, but it is becoming increasingly critical to find alternative high quality ingredients for weaned pig diets due to sustainability concerns. Further processing has allowed soybean meal to become more tolerated by young pigs to increase the nutrient availability and reduce anti-nutritional factors, such as oligosaccharides, glycinin, and beta-conglycinin. These anti-nutritional factors result in gut inflammation and reduced growth performance. A modified soybean meal product may provide a locally produced alternative to fishmeal in early pig diets. A novel microbially-converted soybean meal (MCSBM) has recently been developed with Aureobasidium pullulans to increase the protein content and reduce the anti-nutritional factors. A digestibility trial was conducted to determine the standard ileal digestibility (SID) of protein and amino acids in FM and MCSBM as a potential replacement for FM in weaned pig diets. Six ileal-cannulated barrows (30 ± 1.6kg BW) were used in a 3 × 3 Latin square design with 3 periods of 7 d each (5 d acclimation and 2 d ileal collection of 8 h/d). Pigs were randomly assigned, within period, to one of three experimental diets (FM, MCSBM, and nitrogen-free) where FM and MCSBM were each included as the sole protein source. Titanium dioxide was included in each diet at 0.1% as an indigestible marker. Feed allowance per period was provided at 2.5 x maintenance energy requirement (106 kcal/kg BW0.75) based on measured BW at the beginning of each period. At the beginning of periods 1, 2, and 3, pig BW were 37 ± 1.1, 39.2 ± 2.4, and 42.6 ± 2.7kg, respectively. Data was analyzed using a t-test in SAS. The SID of lysine, methionine, threonine, isoleucine, and leucine were higher (P<0.05) in fishmeal than MCSBM. There was no difference in SID for all other measured amino acids or crude protein. In conclusion, MCSBM contained similar digestible amino acid and crude protein contents compared with FM.
Standard ileal digestible amino acid content (%) in two protein sources fed to pigs
Amino Acid |
Fish meal |
Microbially-converted soybean meal |
SEM |
P-value |
|
Crude protein |
88.8 |
90.3 |
3.0 |
0.625 |
|
Lysine |
93.8 |
88.8 |
0.8 |
<0.001 |
|
Methionine |
93.8 |
91.0 |
0.8 |
0.009 |
|
Threonine |
92.7 |
88.1 |
1.2 |
0.007 |
|
Isoleucine |
94.8 |
91.0 |
0.7 |
0.004 |
|
Leucine |
95.1 |
91.6 |
0.8 |
0.005 |
|
Valine |
92.6 |
90.4 |
0.9 |
0.072 |
|
Histidine |
92.0 |
89.6 |
1.2 |
0.119 |
|
Phenylalanine |
92.5 |
90.9 |
0.8 |
0.125 |
|
Arginine |
93.1 |
94.5 |
2.6 |
0.640 |
|
Keywords: digestibility, fish meal, microbially-converted soybean meal