Growth performance, organ weights, and blood parameters of nursery pigs fed diets containing increasing levels of cold-pressed canola cake.

Oilseed cakes have high oil content, and thus their inclusion in swine can lead to reduced dietary inclusion of oil, and hence reduced cost of feed. An experiment was conducted to determine effects of including Brassica napus-derived cold-pressed canola cake (CPCC) in diets for nursery pigs on growth performance, organ weights relative to live body weight (BW), and blood parameters. A total of 160 pigs (initial BW: 7.8 ± 0.9 kg), which had been weaned at 21 d of age were housed in 40 pens (4 pigs/pen) and fed 4 diets (10 pens/diet) in a randomized complete block design for 35 d. The 4 diets were corn-soybean meal (SBM)-based basal diet and the basal diet with corn and SBM replaced by 20, 30, or 40% of CPCC. The diets were fed in 2 phases, Phase 1 from day 0 to 14 and Phase 2 from day 14 to 35; and were formulated to meet NRC (2012) nutrient recommendations for nursery pigs and to have the same net energy, standardized ileal digestible amino acid, and digestible P contents. Increasing inclusion of CPCC in diets was achieved by partial replacement of corn, SBM, limestone, and mono-calcium phosphate. Growth performance was determined by phase. On day 35, 1 pig from each pen was euthanized for determining organ weights and blood parameters. The CPCC contained 7.63% moisture, and on a dry matter basis, it (CPCC) contained 39.6% crude protein, 2.32% Lys, 0.74% Met, 1.63% Thr, 0.50% Trp, 16.0% ether extract, 20.7% neutral detergent fiber, and 14.9 µmol/g of glucosinolates. Increasing dietary CPCC from 0 to 40% linearly reduced (P < 0.05) overall (day 0 to 35) average daily gain and average daily feed intake (0.440 to 0.288 kg/d and 0.739 to 0.522 kg/d, respectively). Increasing dietary CPCC from 0 to 40% resulted in a linear increase (P < 0.05) in liver weight by 0.1 g/kg of BW and in thyroid gland weight by 2.2 mg/kg of BW, but in a linear reduction (P < 0.05) in serum tetraiodothyronine (T4) level by 0.2 ng/mL for each 1% increase in CPCC at 35 d of age. No differences were observed in heart and kidney weights relative to live BW, and in serum triiodothyronine (T3) concentration. In conclusion, increasing dietary CPCC from 0 to 40% by reducing corn and SBM levels resulted in depressed growth performance, increased metabolic activity in liver and thyroid gland, and reduced serum T4 level of pigs. Thus, the amounts of CPCC included in nursery pig diets should be based on targeted growth performance and cost of other feedstuffs in relation to that of CPCC.