Agriculture Reference
In-Depth Information
Solvent-extracted canola meal, also known as solvent-extracted low glucosinolate and
erucic acid rapeseed meal, can be a valuable protein source for sows, even though it
contains more fiber and less protein than soybean meal. Rapeseed meal contains
glucosinolates which, following enzymatic hydrolysis, yield by-products that have
anti-thyroidic (i.e. goitrogenic) properties (Bell and Baker, 1957). During pregnancy,
these compounds induce thyroid hypertrophy in sows and fetuses, with fetuses being
particularly sensitive. Fetuses' plasma thyroxine concentrations and liveweight decrease
in relation with the glucosinolate levels in the maternal diet. Use of newer canola cultivars
with a very low glucosinolate content obtained through selection, allows feeding of
reproducing sows with diets containing considerably higher inclusion levels as compared
with conventional rapeseed meal (King
et al.
, 2001). Negative health consequences are
avoided when glucosinolate concentration in the diet remains below 2 μM/g. Etienne
et al.
(1975) reported that feed intake, milk yield, and milk composition were similar
between sows fed a barley based diet containing either 11% soybean meal or 21% canola
meal with supplemental crystalline methionine. Average feed intake during lactation was
5.08, 5.50, and 5.67 kg/d for sows offered 0, 101, and 202 g/kg of canola meal, respectively
(King
et al.
, 2001).
Sunflower meal varies greatly in quality grades based on the extent of dehulling and oil
extraction (29 to 33% CP for non-dehulled and 35 to 39% CP for dehulled). Fortunately,
sunflower meal does not have intrinsic anti-nutritional factors and as such does not
require any heat processing. Feed grade sunflower meal is relatively low in energy and
deficient in lysine, but is rich in methionine, hence it is better suited as a source of protein
in gestation than in lactation diets (CETION, 2003). Sunflower meal nicely complements
soybean meal when the latter is fed to lactating sows to meet the lysine requirement.
Corn gluten feed and meal are products of the corn wet milling industry and, as sunflower
meal, are devoid of anti-nutritional factors. Corn gluten feed contains low energy, high
fiber, a modest protein concentration varying between 20 and 25%, is low in digestible
lysine and tryptophan, and has poorer acceptability by sows compared with soybean meal.
Because of its bulkiness, corn gluten feed is not recommended for lactation diets, but may
be readily included as the main or sole source of protein in diets for gestating sows at rates
varying between 50 and 70% (Honeyman and Zimmerman, 1990; Meunier-Salaun, 2001).
Corn gluten meal contains both high energy and digestible amino acids, thus is well suited
as a main protein source in both gestation and lactation diets at a level of 20%.
As mentioned earlier, high quality DDGS is an excellent protein source, but this is
particularly true for gestating sows because of its high fiber content. In gestating sows,
DDGS can replace all of the soybean meal and in lactating sow diets DDGS can replace
a large portion of corn grain and soybean meal, i.e. up to 30% inclusion rate (Stein and
Shurson, 2009).
The animal co-products available for dietary inclusion in swine diets, i.e. spray-dried egg,
blood co-products, poultry meal, meat and bone meal, and fish meal have limited use in
sow diets. Fish meal may be relatively more common. Inclusion rate for these products
in sow diets is usually restricted to 3% or less (Patience
et al.
, 1995). Nonetheless, the
