The effects of feeding canola meal from high protein or conventional varieties of canola seeds on pork quality

Canola meal (CM) can be a valuable alternative to soybean meal (SBM) as a protein supplement for pigs. However, it has a lower crude protein content and about 3 times as much fiber as soybean meal, thus limiting the availability of essential amino acids and digestible energy in pig diets, and potentially decreasing carcass yield. Furthermore, the presence of glucosinolates in some varieties of canola caused hypothyroidism and enlarged thyroid glands in pigs, which lead to decreased animal growth. A new hybridized high protein variety of canola (Brassica napus) contains approximately 45% crude protein and may be a more desirable option as a SMB alternative than historic varieties of canola because of its higher protein and lower crude fiber content. Sinapine is another anti-nutritional component found in CM, which caused a “fishy” smell in the eggs of laying hens. While feeding CM to pigs did not have negative effects on sensory attributes of pork loins, effects on bacon sensory characteristics had not been evaluated. Furthermore, CM is high in polyunsaturated fatty acids (PUFA), which could lead to soft, thin bellies and complications during bacon processing. Research has been conducted at the University of Illinois to determine the effects of conventional (CM-CV) or high protein (CM-HP) canola meal diets for nursery pigs, although no research has been conducted on feeding CM-HP to growing and finishing pigs. Therefore, two experiments were conducted to evaluate the effects of CM-HP and CM-CV on pork quality of growing and finishing pigs. The objectives of the first experiment were to determine growth performance, carcass characteristics, and meat quality of growing and finishing pigs fed both types of CM. The objectives of the second experiment were to determine processing and sensory attributes of dry or conventionally cured bacon from pigs fed both types of CM. A 3-phase 91 d feeding program was used with grower diets fedfrom d 0 to d 35, finisher-1 diets fed from d 36 to d 63, and finisher-2 diets fed from d iii 64 to d 91. Seven diets were fed, which included a corn-SBM diet (control), 3 diets containing increasing inclusion rates of CM-HP, and 3 diets containing increasing inclusion rates of CM-CV. Canola meal replaced 33, 66, or 100% of the soybean meal in the diets. A total of 280 pigs were used in the study, with 70 pens and a total of 4 pigs per pen. One pig from each pen was randomly selected for a meat quality evaluation at the end of the feeding period. Therefore, 140 bellies (2 bellies from each of 70 pigs) were used for the second experiment. In the first experiment, overall ADFI was increased by about 6% for pigs fed 66% CM-CV when compared to pigs fed all levels of CM-HP and pigs fed the control. Furthermore, there was a linear increase in ADFI as CM-CV inclusion level increased. There were only a few differences in organ and viscera weights, however, there was a linear increase in liver percentage as CM-CV inclusion increased. There were no differences among treatments for any subjective evaluations (color, marbling, firmness), drip loss, proximate composition, cook loss, or shear force, however, there was a linear decrease in pH in pigs fed CM-HP. In study 2, there were no differences among dietary treatments for all fresh belly characteristics, most fatty acids, and calculated iodine value. However, there was a linear increase in total PUFA as CM-HP inclusion increased. Conventionally cured bacon and dry cured bacon were analyzed separately. There were no differences in either cure type for processing characteristics, bacon slice characteristics, and proximate composition. Furthermore, sensory panel evaluations of saltiness, flavor intensity, off flavor, and off odor were similar among dietary treatments in both types of bacon. Overall, CM-HP and CM-CV can replace soybean meal in growing-finishing pig diets without any detrimental effects on animal growth, carcass characteristics, meat quality, or bacon characteristics. Canola meal is a viable alternative to soybean meal as a protein supplement in pig diet