Effects of protein concentration and heat treatment on concentration of digestible and metabolizable energy and on amino acid digestibility in four sources of canola meal fed to growing pigs

Comparison of Amino Acid Digestibility between Commercial Crossbred Pigs and Mini-Jeju Island Native Pigs

The objectives of this study were to determine the apparent ileal digestibility and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in feed ingredients, compare the ileal digestibility of CP and AA between commercial crossbred pigs and mini-Jeju Island native pigs (JINP), and develop models for estimating SID of CP and AA for commercial pigs using mini-JINP data. The study involved five crossbred commercial pigs (31.5 ± 1.6 kg of body weight and 11 weeks of age; Landrace × Yorkshire) and five mini-JINP (31.0 ± 3.2 kg body weight and 20 weeks of age). The pigs were surgically equipped with a T-cannula at the end of ileum. Each pig breed was assigned to 5 dietary treatments in a 5 × 10 incomplete Latin square design with 10 periods. Four experimental diets were formulated to contain each of soybean meal, corn gluten feed, copra meal, and sesame expellers as the sole source of nitrogen. A nitrogen-free diet was also prepared to determine basal endogenous losses of CP and AA. No interaction between breed and feed ingredient was observed for the digestibility of CP and all indispensable AA. The SID of CP and all indispensable AA, except Arg, His, and Lys, did not differ between the two breeds of pigs. Prediction equations were developed for SID of CP and AA of commercial pigs using the SID values of mini-JINP: SID of CP (%) = (1.02 × SID of CP in mini-JINP) - 5.20 with r2 = 0.97 and p < 0.05; SID of Lys (%) = (1.12 × SID of Lys in mini-JINP) - 9.10 with r2 = 0.98 and p < 0.05; and SID of Met (%) = (1.08 × SID of Met in mini-JINP) - 4.27 with r2 = 0.96 and p < 0.05. The digestibility for most AA in feedstuffs for commercial pigs can be estimated using data from mini-JINP.

Improved in vitro gastrointestinal digestion protocol mimicking brush border digestion for the determination of the Digestible Indispensable Amino Acid Score (DIAAS) of different food matrices

The Digestible Indispensable Amino Acid Score (DIAAS) is the new gold standard method for the assessment of protein nutritional quality. The DIAAS is evaluated with in vivo models, that are complex, constraining and costly. There is still no established method to assess it in vitro. In this study, we proposed to add a jejunal-ileal digestion phase to the standardized in vitro gastrointestinal digestion protocol developed by the International Network of Excellence on the Fate of Food in the Gastrointestinal Tract (INFOGEST protocol) to mimic brush border digestion and to enable DIAAS assessment in vitro in a more physiologically relevant manner. This jejunal-ileal digestion phase was performed with a porcine intestinal aminopeptidase as an alternative to brush border membrane extract, which is more difficult to obtain in a standardized way. This modified INFOGEST protocol was applied to various food matrices (faba bean, pea and soy flours, whey protein isolate and caseins) and the results were compared to published in vivo data to assess the model's physiological relevance. The addition of the jejunal-ileal digestion phase lead to a significant (p < 0.05) increase of 31 and 29 % in free and total amino acid digestibility, respectively, and of 83 % on average for the in vitro DIAAS values for all food matrices. Although the in vitro DIAAS remained underestimated compared to the in vivo ones, a strong correlation between them was observed (r = 0.879, p = 0.009), stating the relevance of this last digestion phase. This improved digestion protocol is proposed as a suitable alternative to evaluate the DIAAS in vitro when in vivo assays are not applicable.

Protein quality of soy and the effect of processing: A quantitative review

There is a growing demand for plant-based protein-rich products for human consumption. During the production of plant-based protein-rich products, ingredients such as soy generally undergo several processing methods. However, little is known on the effect of processing methods on protein nutritional quality. To gain a better understanding of the effect of processing on the protein quality of soy, we performed a quantitative review of in-vivo and in-vitro studies that assessed the indispensable amino acid (IAA) composition and digestibility of varying soy products, to obtain digestibility indispensable amino acids scores (DIAAS) and protein digestibility corrected amino acid scores (PDCAAS). For all soy products combined, mean DIAAS was 84.5 ± 11.4 and mean PDCAAS was 85.6 ± 18.2. Data analyses showed different protein quality scores between soy product groups. DIAAS increased from tofu, soy flakes, soy hulls, soy flour, soy protein isolate, soybean, soybean meal, soy protein concentrate to soymilk with the highest DIAAS. In addition, we observed broad variations in protein quality scores within soy product groups, indicating that differences and variations in protein quality scores may also be attributed to various forms of post-processing (such as additional heat-treatment or moisture conditions), as well as study conditions. After excluding post-processed data points, for all soy products combined, mean DIAAS was 86.0 ± 10.8 and mean PDCAAS was 92.4 ± 11.9. This study confirms that the majority of soy products have high protein quality scores and we demonstrated that processing and post-processing conditions can increase or decrease protein quality. Additional experimental studies are needed to quantify to which extent processing and post-processing impact protein quality of plant-based protein-rich products relevant for human consumption.

Rapeseed meal as a feed component in monogastric animal nutrition – a review

Rapeseed is an important oil crop worldwide, with an annual production of more than 70 million tons. Rapeseed meal (RSM) is a by-product of rapeseed oil production and is second after soybean meal (SBM) in the world production of protein meal. Rapeseed meal derived from black-seeded winter oilseed rape (Brassica napus L.) usually contains between 35 and 40% of crude protein (CP), which is considered to be one of the more valuable plant proteins. It has a good balance of essential amino acids and a very high protein efficiency ratio (PER=3.29). However, full utilisation of this protein is difficult due to presence of the non-protein components of the seed which are associated with it. These are called antinutritional factors and they limit the utilisation of RSM in monogastric animal nutrition. The main antinutritional factors in RSM are dietary fibre, glucosinolates, phytic acid, and phenolic compounds (sinapine, tannins). For many years, research has been conducted in many centers around the world to improve the nutritional value of RSM, which will consequently increase its use in feeding monogastric animals. The attempts that have been undertaken include breeding strategy, optimisation, modernisation and better control of the oil extraction process, as well as technological treatments of seeds and meal. This review provides information on how RSM has evolved in recent years, as well as on its nutritive value, particularly protein, fibre and glucosinolate content. Techniques which have been used to improve the nutritional value of rapeseed products are also discussed. However, the used methods do not allow for full replacement soybean meal by RSM in monogastric animal nutrition.

Comprehensive overview of the quality of plant- And animal-sourced proteins based on the digestible indispensable amino acid score

Indispensable amino acid (IAA) composition and standardized ileal digestibility (SID) of five animal- and 12 plant-based proteins were used to calculate their respective Digestible Indispensable Amino Score (DIAAS) according to the three age categories defined by the Food and Agriculture Organization (FAO). Mean IAA content and mean SID obtained from each protein dataset were subsequently used to simulate optimal nutritional quality of protein mixtures. Datasets revealed considerable variation in DIAAS within the same protein source and among different protein sources. Among the selected protein sources, and based on the 0.5- to 3-year-old reference pattern, pork meat, casein, egg, and potato proteins are classified as excellent quality proteins with an average DIAAS above 100. Whey and soy proteins are classified as high-quality protein with an average DIAAS ≥75. Gelatin, rapeseed, lupin, canola, corn, hemp, fava bean, oat, pea, and rice proteins are classified in the no quality claim category (DIAAS <75). Potato, soy, and pea proteins can complement a broad range of plant proteins, leading to higher DIAAS when supplied in the form of protein mixtures and at specific ratios. Such complementarity highlights the potential to achieve an optimal nutritional efficiency with plant proteins alone.

Hydrolysis of plant proteins at the molecular and supra-molecular scales during in vitro digestion

The digestion of plant protein is highly dependent on multiple factors, with two of the most important being the protein source and the food matrix. The present study investigated the effects of these two factors on the digestion of seitan (a wheat-based food), tofu, soya juice, and a homemade emulsion of soy oil and water that was stabilised with pea protein. The four plant matrices and their respective protein isolates/concentrates (wheat gluten, soya protein, pea protein) were subjected to in vitro static digestion following the INFOGEST consensus protocol. We monitored the release of α-amino groups during digestion. We found that food matrix had a strong influence on protein digestion: soya juice was more hydrolysed than fresh tofu (51.1% versus 33.1%; P = 0.0087), but fresh tofu was more hydrolysed than soya protein isolate (33.1% versus 17.9%; P < 0.0001). Likewise, the pea-protein emulsion was better hydrolysed than the pea-protein isolate (P = 0.0033). Differences were also detected between the two solid foods investigated here: a higher degree of hydrolysis was found for tofu compared to seitan (33.1% versus 11.8%), which was perhaps a function of the presence of numerous dense protein aggregates in the latter but not the former. Furthermore, freeze-drying more than doubled the final degree of hydrolysis of seitan (P < 0.0001), but had no effect on tofu (P = 1.0000). Confocal microscopy revealed that protein networks in freeze-dried seitan were strongly altered with respect to the fresh product; instead, protein networks in freeze-dried and fresh tofu were largely similar. Finally, we found that the protease:protein ratio had a strong effect on the kinetics of proteolysis: a 3.7-fold increase in the concentration of the soya protein isolate with respect to that of the soya juice decreased the final degree of hydrolysis from 50.3 to 17.9% (P = 0.0988).

At least 3 days of adaptation are required before indigestible markers (chromium, titanium, and acid insoluble ash) are stabilized in the ileal digesta of 60-kg pigs, but values for amino acid digestibility are affected by the marker

An experiment was conducted to 1) test the hypothesis that a minimum adaptation period to diets used in ileal amino acid (AA) digestibility experiments with pigs is needed and 2) to test the null-hypothesis that ileal digestibility and basal endogenous losses of AA are not affected by the indigestible marker used. Eight ileal-cannulated barrows with an initial BW of 58.1 ± 4.3 kg were randomly allotted to a 2-period crossover design with 2 diets and 4 pigs per diet in each period. A soybean meal-based diet and an N-free diet were prepared. Both diets contained 0.4% chromium oxide, 0.4% titanium dioxide, and 0.4% Celite (a source of acid insoluble ash; AIA). Pigs were provided feed in a daily amount of 3 times the maintenance requirement for metabolizable energy, and 2 equal meals were provided each day. Ileal digesta samples were collected from 0800 to 2000 h on each day during the two 9-d collection periods. There was no period by diet interactions observed. Marker concentrations in ileal digesta were analyzed separately for each day, and the point where the concentration of each marker was stabilized in the digesta was determined using a linear broken-line analysis. For pigs fed the soybean meal diet, the breakpoints for Cr, Ti, and AIA in ileal digesta were 2.70, 2.45, and 3.77 d, respectively. In pigs fed the N-free diet, the breakpoints for Cr, Ti, and AIA in ileal digesta were 2.52, 2.39, and 2.29 d, respectively. Based on the pooled data, the basal endogenous losses of most AA calculated using Cr as an indigestible marker were less (P < 0.05) than the values calculated using Ti, but greater (P < 0.05) compared with values calculated based on AIA. The standardized ileal digestibility of most AA in soybean meal calculated using Cr or Ti as a digestibility marker were greater (P < 0.05) than the digestibility values calculated using AIA. In conclusion, 3 d of adaptation is required before markers are stabilized in the ileal outflow if Cr or Ti is used as an indigestible marker and 4 d of adaptation is required if AIA is the marker. Values for AA digestibility calculated using Cr or Ti as the marker are not different, but greater compared with values calculated using AIA as the marker.

The Effect of Hydrothermally Processed Soybean- and Rapeseed-Based Diets on Performance, Meat and Carcass Quality Characteristics in Growing-Finishing Pigs

The experiment was performed on 60 crossbred weaners with average initial body weight (BW) of 22 kg. The animals were divided into 4 groups, with 15 animals (10 males and 5 females) per group, based on the percentage content of the following components in complete diets: soybean meal, toasted full-fat soybeans, cold-pressed rapeseed cake with increased oil content, extruded rapeseed cake with increased oil content. The growth performance of pigs, carcass characteristics, meat quality and the fatty acid profile of depot fat were determined. The pigs fed complete diets containing toasted soybeans had higher average daily gain (ADG). The animals receiving cold-pressed rapeseed cake were characterised by lower ADG and higher FCR. The carcasses of pigs fed diets containing cold-pressed rapeseed cake and extruded rapeseed cake had lower lean content than the carcasses of pigs administered toasted soybeans. The analysed feedstuffs had no effect on back-fat thickness or meat quality. Cold-pressed and extruded rapeseed cake contributed to changes in the fatty acid profile of backfat, including an increase in the concentrations of monounsaturated fatty acids (MUFAs) and a more desirable n-6/n-3 PUFA ratio. The extrusion processing of rapeseed cake decreased the content of lysine and methionine with cystine by approximately 4%, and reduced total glucosinolate content by approximately 17%. The inclusion of toasted soybeans in pig diets contributed to higher BW gain and carcass dressing percentage. Rapeseed cake with increased oil content led to desirable changes in the fatty acid profile of backfat.

Amino acid digestibility in plant protein sources fed to growing pigs

Objective

The objective was to determine standardized ileal digestibility (SID) of amino acids (AA) in 11 plant protein sources fed to growing pigs.

Methods

Eleven feed ingredients used were sesame meal, two sources of soybean meal (SBM) produced in the Republic of Korea, a source of SBM produced in India, high-protein distillers dried grains (HPDDG), perilla meal, canola meal, copra meal, corn germ meal, palm kernel expeller, and tapioca distillers dried grains (TDDG). Experimental diets were prepared to contain each test ingredient as a sole source of AA, and a nitrogen-free diet was also prepared to estimate the basal ileal endogenous losses of AA. Twelve barrows surgically fitted with T-cannulas at the distal ileum with an initial body weight of 29.0 kg (standard deviation = 3.0) were individually housed in metabolism crates equipped with a feeder and a nipple drinker. A 12×9 incomplete Latin square design was employed with 12 experimental diets, 12 animals, and 9 periods. After a 5-d adaptation period, ileal digesta were collected on d 6 and 7 in each experimental period.

Results

Values for apparent ileal digestibility of most indispensable AA in three sources of SBM were greater compared with other test ingredients except HPDDG and canola meal (p<0.05). Pigs fed diets containing SBM sources had also greater SID of most indispensable AA compared with those fed diets containing other test ingredients (p<0.05) except for HPDDG and canola meal. There was no difference in the apparent ileal digestibility and SID of AA among sources of SBM. The TDDG had the least value for the SID of methionine among test ingredients (p<0.05).

Conclusion

The SID of most AA in SBM, HPDDG, and canola meal were greater than those in sesame meal, perilla meal, copra meal, and TDDG.

Canola meal produced from high-protein or conventional varieties of canola seeds may substitute soybean meal in diets for gestating and lactating sows without compromising sow or litter productivity

An experiment was conducted to test the hypothesis that productivity of sows fed diets containing canola meal produced from high-protein or conventional varieties of canola seeds is not different from that of sows fed corn-soybean meal (SBM) diets. A total of 180 sows (initial BW: 207.8 ± 29.11 kg) were randomly allotted to 1 of 5 diets with 36 to 40 sows per diet. A 2-phase feeding program was used with gestation diets fed from day 7 of gestation to farrowing and lactation diets fed during the lactation period and from weaning to first estrus. The 5 diets within each phase consisted of a control diet based on corn and SBM, 2 diets were based on corn and high-protein canola meal (CM-HP) that was included to replace 50 or 100% of the SBM in the control diet, and 2 diets contained conventional canola meal (CM-CV) included to replace 50 or 100% of the SBM in the control diet. Soybean hulls were included in diets fed during gestation to standardize the concentration of NDF to approximately 13% in all diets. However, no soybean hulls were used in lactation diets resulting in increased concentrations of NDF as the dietary concentration of CM-HP or CM-CV increased. Results of the experiment indicated that there were no differences in sow BW changes during gestation, in sow BW on day 1 post-farrowing, or at weaning due to dietary treatments. No differences were observed among diets in ADFI during gestation or lactation or in the number of total pigs born, pigs born alive, still-born pigs, or weaned pigs per litter. Likewise, no differences were observed among diets in litter birth weight, live litter birth weight, litter BW at weaning, or litter ADG. As the inclusion level of CM-HP or CM-CV increased, the percentage of pigs surviving during the lactation period increased (linear, P < 0.05), but the wean to first estrus interval also increased as the dietary concentration of CM-CV increased (linear, P < 0.05). Average pig BW at weaning and pig ADG decreased (linear, P < 0.05) as the inclusion level of CM-HP increased. No differences were observed between CM-HP and CM-CV with the exception that pigs born from sows fed CM-CV during gestation had greater (P < 0.05) average live pig birth weight compared with pigs born from sows fed CM-HP during gestation. Results of this experiment indicate that CM-HP or CM-CV may replace all SBM in diets fed to sows during gestation and lactation.

Pelleting and extrusion can ameliorate negative effects of toasting of rapeseed meal on protein digestibility in growing pigs

Toasting time (TT) of rapeseed meal (RSM), the diet processing (DP) method and the interaction between both on the apparent CP digestion along the gastrointestinal tract and the apparent ileal digestibility (AID) of amino acids of growing pigs were investigated. The experiment consisted of a 3×3 factorial design of TT of RSM (0, 60 and 120 min) and DP method (mash, pelleting and extrusion). In total, 81 boars with a starting BW of 20 kg were euthanized 4 h after their last feeding. The gastrointestinal tract was dissected and the small intestine divided in three sections of similar length. Samples were collected from the stomach, 1.5 m from the ends of each of the three sections of the small intestine, and the rectum. The apparent digestibility (AD) of CP for each of the small intestine sections was used to calculate the rate of CP digestion. Increasing the TT of RSM resulted in lower protein solubility, lower lysine/reactive lysine contents and higher protein denaturation, indicative of the occurrence of protein aggregation and Maillard reactions. There were significant effects (P⩽0.01) of TT on the AD of CP in the different sections of the gastrointestinal tract. The rate of CP digestion of the 0 min toasted RSM diets was 23% and 35% higher than that of the 60 and 120 min toasted RSM diets, respectively. There was a significant interaction (P=0.04) between TT and DP for the AID of CP. Although pelleting of the 0 and 60 min toasted RSM diets did not change the AID of CP with respect to the mash diets, pelleting of the 120 min toasted RSM diet increased the AID of CP by 9.3% units. Extrusion increased the AID of CP of the 0 and 60 min toasted RSM diets by 3.4% and 4.3% units with respect to the mash diets, whereas extrusion of the 120 min toasted RSM diet increased the AID of CP by 6.9% units. Similar positive effects of pelleting and extrusion were obtained for the AID of lysine and reactive lysine, especially in the diets with higher TT. In conclusion, processing (pelleting and extrusion) of RSM containing diets can ameliorate the negative effects of RSM toasting on protein and amino acid digestibility; these effects were larger for the RSM toasted for longer times.

Utilizing pretreatment and fungal incubation to enhance the nutritional value of canola meal

AIMS

The objective of this study was to determine the optimal pretreatment and fungal strain to reduce glucosinolates (GLS), fibre and residual sugars while increasing the nutritional value of canola meal.

METHODS AND RESULTS

Submerged incubation conditions were used to evaluate four pretreatment methods (extrusion, hot water cook, dilute acid and dilute alkali) and three fungal cultures (Aureobasidium pullulans Y-2311-1, Fusarium venenatum NRRL-26139 and Trichoderma reesei NRRL-3653) in hexane-extracted (HE) and cold-pressed (CP) canola meal.

CONCLUSIONS

The combination of extrusion pretreatment followed by incubation with T. reesei resulted in the greatest overall improvement to HE canola meal, increasing protein to 51·5%, while reducing NDF, GLS and residual sugars to 18·6%, 17·2 μmol l^-1  g^-1 and 5% w/w, respectively. Extrusion pretreatment and incubation with F. venenatum performed the best with CP canola meal, resulting in 54·4% protein while reducing NDF, GLS and residual sugars to 11·6%, 6·7 μmol l^-1  g^-1 and 3·8% w/w respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

The work is significant in that it provides a method of reducing GLS (up to 98%) and neutral detergent fibre (up to 65%) while increasing the protein content (up to 45%) of canola meal. This novel pretreatment and submerged incubation process could be used to produce a canola product with higher nutritional value for livestock consumption.

Effects of graded levels of microbial phytase on apparent total tract digestibility of calcium and phosphorus and standardized total tract digestibility of phosphorus in four sources of canola meal and in soybean meal fed to growing pigs

One hundred twenty pigs were used to determine effects of graded levels of microbial phytase on the apparent total tract digestibility (ATTD) of P and Ca and the standardized total tract digestibility (STTD) of P in 4 sources of canola meal and in 1 source of soybean meal (SBM) fed to growing pigs. The 4 sources of canola meal were produced from 1 source of high-protein canola seeds and 2 sources of conventional canola seeds with 1 of the conventional canola seeds being divided into 2 separate batches before crushing. Pigs (16.2 ± 5.3 kg initial BW) were individually housed in metabolism crates and were randomly allotted to 1 of 20 diets in a 5 × 4 factorial arrangement of treatments with 5 ingredients and 4 levels of phytase. There were 6 replicate pigs per diet. Five basal diets based on high-protein canola meal (CM-HP), high-temperature processed canola meal (CM-HT), low-temperature processed canola meal (CM-LT), conventional canola meal (CM-CV), or SBM were formulated. The basal diets contained no phytase. Fifteen additional diets were prepared by adding approximately 500, 1,500, or 2,500 phytase units/kg to each of the 5 basal diets. Feces were quantitatively collected for 5 d based on the marker-to-marker approach after a 7-d adaptation period. Results indicated that supplementation of microbial phytase increased (linear, < 0.05) the ATTD of Ca in diets containing CM-HP, CM-HT, CM-CV, and SBM but not in diets containing CM-LT. Microbial phytase also increased (linear and quadratic, < 0.05) the ATTD and STTD of P in all 5 ingredients. Compared with the CM-CV diets, the CM-HP diets had greater ( < 0.05) ATTD of Ca. The ATTD of Ca in the SBM diet was greater ( < 0.05) than in all canola meal diets, but no differences were observed in ATTD of Ca between CM-HT and CM-LT diets. The ATTD and the STTD of P were less ( < 0.05) in CM-HP, CM-HT, CM-LT, or CM-CV than in SBM if no microbial phytase was added, but no differences were observed in the ATTD and STTD of P in SBM, CM-HP, CM-HT, or CM-CV if the highest amount of phytase were added (interaction, < 0.05). Regression equations were developed to calculate the response to microbial phytase on the STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM. In conclusion, inclusion of graded levels of microbial phytase increased the ATTD and STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM and the response to microbial phytase added to each ingredient can be predicted by regression equations.

Effects of diet energy concentration and an exogenous carbohydrase on growth performance of weanling pigs fed diets containing canola meal produced from high protein or conventional canola seeds

The objectives were to determine effects of diet NE and an exogenous carbohydrase on growth performance and physiological parameters of weanling pigs fed a corn-soybean meal (SBM) diet or diets containing high protein canola meal (CM-HP) or conventional canola meal (CM-CV). A total of 492 pigs (initial BW: 9.15 ± 0.06 kg) were used in a randomized complete block design with 12 dietary treatments and 9 pens per treatment. A control diet based on corn and SBM and 4 diets containing 20% or 30% CM-HP or 20% or 30% CM-CV were formulated to a similar NE by adjusting inclusion of choice white grease. Four additional diets also contained 20% or 30% CM-HP or 20% or 30% CM-CV, but no additional choice white grease, and NE in these diets, therefore, was less than in the control diet. The control diet and the diets containing 30% CM-HP or CM-CV without increased choice white grease were also formulated with inclusion of an exogenous carbohydrase. Pigs were fed experimental diets for 22 d and 1 pig per pen was sacrificed at the conclusion of the experiment. Results indicated that compared with the control diet, there was no impact of canola meal on final BW, ADG, ADFI, or G:F, but pigs fed CM-CV had greater ( < 0.05) final BW, ADG, and ADFI than pigs fed CM-HP, and pigs fed diets with reduced NE had greater ( < 0.05) ADG and ADFI than pigs fed diets with constant NE. Only minor effects of CM-HP or CM-CV on intestinal weight, gut fill, digesta pH, cecal VFA concentrations, and serum concentrations of urea N, total N, or albumin were observed, but the weight of the thyroid gland increased ( < 0.05) as the concentration of dietary canola meal increased. Serum concentrations of IgG were reduced if canola meal was included in the diets without the carbohydrase, but that was not the case if the carbohydrase was included in the diet (interaction, ( < 0.05). In conclusion, up to 30% CM-HP or CM-CV in diets fed to weanling pigs from 2 wk postweaning did not impact growth performance compared with pigs fed a corn-SBM diet, and NE in diets containing canola meal does not have to be similar to that of corn-SBM diets. However, inclusion of CM-CV containing 4.43 µmol/g glucosinolates in the diets resulted in improved growth performance compared with inclusion of CM-HP containing 12.60 µmol/g glucosinolates.

Physical and chemical changes of rapeseed meal proteins during toasting and their effects on in vitro digestibility

BACKGROUND

Toasting during the production of rapeseed meal (RSM) decreases ileal crude protein (CP) and amino acid (AA) digestibility. The mechanisms that determine the decrease in digestibility have not been fully elucidated. A high protein quality, low-denatured, RSM was produced and toasted up to 120 min, with samples taken every 20 min. The aim of this study was to characterize secondary structure and chemical changes of proteins and glucosinolates occurring during toasting of RSM and the effects on its in vitro CP digestibility.

RESULTS

The decrease in protein solubility and the increase of intermolecular β-sheets with increasing toasting time were indications of protein aggregation. The contents of NDF and ADIN increased with increasing toasting time. Contents of arginine, lysine and O-methylisourea reactive lysine (OMIU-RL) linearly decreased with increasing toasting time, with a larger decrease of OMIU-RL than lysine. First-order reactions calculated from the measured parameters show that glucosinolates were degraded faster than lysine, OMIU-RL and arginine and that physical changes to proteins seem to occur before chemical changes during toasting. Despite the drastic physical and chemical changes noticed on the proteins, the coefficient of in vitro CP digestibility ranged from 0.776 to 0.750 and there were no effects on the extent of protein hydrolysis after 120 min. In contrast, the rate of protein hydrolysis linearly decreased with increasing toasting time, which was largely correlated to the decrease in protein solubility, lysine and OMIU-RL observed. Rate of protein hydrolysis was more than 2-fold higher for the untoasted RSM compared to the 120 min toasted material.

CONCLUSIONS

Increasing the toasting time for the production of RSM causes physical and chemical changes to the proteins that decrease the rate of protein hydrolysis. The observed decrease in the rate of protein hydrolysis could impact protein digestion and utilization.

Effects of high-protein or conventional canola meal on growth performance, organ weights, bone ash, and blood characteristics of weanling pigs

An experiment was conducted to evaluate effects of 2 high-protein canola meals (canola meal A [CMA]: 45.69% CP and canola meal B [CMB]: 46.97% CP) and a conventional canola meal (CM-CV: 35.10% CP) on growth performance, organ weights, bone ash, and blood parameters of weanling pigs. Inclusion rates of canola meal (CM) in the diets were 10, 20, 30, or 40% for CMA and CM-CV, whereas inclusions were 10, 20, or 30% for CMB. A control diet containing no CM was also formulated. Therefore, 12 diets were used in this experiment. A total of 420 pigs (initial BW: 9.8 ± 1.1 kg) were divided into 3 blocks and randomly allotted to 1 of the 12 diets with 8 replicate pens per treatment and 4 or 5 pigs per pen. The ADG, ADFI, and G:F were calculated, and at the conclusion of the experiment, 1 pig in each pen was euthanized to allow measurements of organ weights, collection of blood, and collection of the third and fourth metacarpals from the left foot. Results indicate that ADFI was linearly (P < 0.05) decreased if inclusion of CMA, CMB, or CM-CV was increased. Average daily gain for pigs fed CMA tended to increase quadratically with the maximum response observed at 10 or 20% CM inclusion in the diet ( P= 0.06). However, G:F was linearly (P < 0.05) increased by adding CMA or CM-CV to the diets. Liver weights were also linearly (P < 0.05) increased if pigs were fed diets containing CMB, but kidney weights were linearly (P < 0.05) decreased by the addition of CM-CV to the diets. Thyroid gland weights increased linearly (P < 0.05) for pigs fed diets containing CMA. No differences were observed in heart and bone weights if CM was added to the diets. Addition of any of the 3 CM linearly (P < 0.05) increased bone ash percentage in the metacarpals. Inclusion of CMA or CM-CV linearly (P < 0.05) decreased concentrations of serum triiodothyronine, and the inclusion of CMA also linearly (P < 0.05) decreased serum thyroxine concentrations. No differences were observed for complete blood counts or blood urea nitrogen if CM was added to the diets. In conclusion, up to 20% high-protein CM or CM-CV may be included in diets for weanling pigs from 2 wk postweaning without reducing growth performance or negatively affecting organ, bone, or blood parameters. In some instances, it may also be possible to use greater inclusion rates.