Canola meal and soybean meal (SBM) are the most commonly used sources of amino acids in diets for swine. However, via genetic selection, varieties of canola with greater concentrations of crude protein and reduced concentrations of fiber have been identified. Following oil extraction, the resulting high-protein canola meal (CM-HP) contains 3 to 5 % more crude protein than conventional canola meal (CM-CV). It is, therefore, expected that CM-HP contains more digestible and metabolizable energy than CM-CV, but this hypothesis has not been experimentally verified (Liu et al., 2016). Therefore, it is the objective of this experiment to determine the apparent total tract digestibility (ATTD) of energy and concentrations of digestible energy (DE) in CM-HP, CM-CV, and SBM when fed to lactating sows.
Experimental Design
The main ingredients used in the current experiment were yellow dent corn, CM-HP, CM-CV, and SBM (Table 1). A corn-based basal diet and three diets based on a mixture of corn and CM-HP, CM-CV, or SBM were formulated (Table 2). All diets contained titanium dioxide as an indigestible marker.
Animals and Housing
Thirty-six multiparous lactating Camborough females (Pig Improvement Company, Hendersonville, TN, USA) were allotted to a randomized complete block design with three blocks of 12 sows, four diets, and three sows per diet in each block, for a total of nine replicate sows per diet. Sows were moved to farrowing crates seven days before farrowing and remained there until weaning on day 20 post-farrowing.
Sample and data collection
Sows were fed experimental diets from day five post-farrowing until day 18 post-farrowing. Diets were provided ad libitum, and water was available at all times. The initial seven days of the feeding period (i.e., from day 5 to day 11) were the adaptation period to the experimental diets, and fecal samples were collected once daily from day 12 to day 17 via grab sampling. Collected fecal samples were stored at –20 oC immediately after collection.
Results
Daily feed intake and gross energy intake were greater (P < 0.05) by sows fed the CM-HP or the CM-CV diet compared with sows fed the corn diet (Table 3). The ATTD of dry matter and GE were greater (P < 0.05) for the corn and SBM diets compared with CM-HP and CM-CV diets. Digestible energy in diets was greater (P < 0.05) in the SBM diet compared with the CM-CV diet, but no differences in DE were observed among the corn, CM-HP, and SBM diets. Digestible energy on as-is basis was less (P < 0.05) in CM-HP and CM-CV compared with SBM, but there was no difference between corn and the other ingredients. The DE to GE ratio was greater (P < 0.05) in corn and SBM compared with the CM-HP and the CM-CV.
Conclusion
These results demonstrate that genetic improvement of canola reduces fiber and enhances energy utilization compared with conventional canola meal. Nevertheless, soybean meal provides more digestible energy than canola meal when fed to lactating sows.
Appreciation
Funding for this research from Agrigenetics, Canada is greatly appreciated.
Table 1. Analyzed nutrient composition of feed ingredients, as-is basis
Table 2. Ingredient and analyzed composition of experimental diets containing high-protein canola meal, conventional canola meal, and soybean meal fed to lactating sows, as-is basis
1The vitamin-micromineral premix provided the following quantities of vitamins and micro minerals per kg of complete diet: vitamin A as retinyl acetate, 10,622 IU; vitamin D3 as cholecalciferol, 1,660 IU; vitamin E as DL-alpha-tocopherol acetate, 66 IU; vitamin K as menadione nicotinamide bisulfate, 1.40 mg; thiamin as thiamine mononitrate, 1.08 mg; riboflavin, 6.49 mg; pyridoxine as pyridoxine hydrochloride, 0.98 mg; vitamin B12, 0.03 mg; D-pantothenic acid as D-calcium pantothenate, 23.2 mg; niacin, 43.4 mg; folic acid, 1.56 mg; biotin, 0.44 mg; Cu, 20 mg as copper chloride; Fe, 123 mg as iron sulfate; I, 1.24 mg as ethylenediamine dihydroiodide; Mn, 59.4 mg as manganese hydroxychloride; Se, 0.27 mg as sodium selenite and selenium yeast; and Zn, 124.7 mg as zinc hydroxychloride.
2The phytase premix was prepared by mixing corn and microbial phytase concentrate (QuantumBlue; AB Vista Feed Ingredients, Marlborough, UK; 10000 units of phytase/g). The premix was prepared by adjusting the inclusion of phytase in such a way that 0.2 % of the phytase premix provided 500 phytase units per kg of the complete diet.
Table 3. Apparent total tract digestibility (ATTD) of dry matter and gross energy, and digestible energy (DE) in experimental diets and ingredients fed to lactating sows1, as-fed basis
a-bWithin a row, means without a common superscript differ (P < 0.05).
1Each least square mean represents 8 observations per diet.
2Concentration of DE in corn was calculated by dividing DE in the corn diet by 96.20%.