Double-low Rapeseed Research Articles

Development and Validation of Equations for Predicting the Metabolizable Energy Value of Double-Low Rapeseed Cake for Growing Pigs.

Simple SummaryDouble-low rapeseed cake could be a cost-effective feed resource for swine, providing amino acids and energy. Accurate evaluation of the energy values of different double-low rapeseed cakes is of great significance to economically and effectively formulate diets when double-low rapeseed cakes are used as an alternative ingredient in diets fed to pigs. Therefore, two experiments were conducted to develop and validate an equation to predict the metabolizable energy of double-low rapeseed cake for growing pigs based on chemical compositions. Results indicated that the best-fit prediction equation for metabolizable energy (MJ/kg) was 9.33 − 0.09 × neutral detergent fiber −0.25 × crude fiber + 0.59 × gross energy (R2 = 0.93). Increasing levels of double-low rapeseed cake linearly reduced apparent total tract digestibility of nutrients, but did not affect growing performance and caloric efficiency of metabolizable energy of growing pigs fed diets balanced for standardized ileal digestibility Lys/metabolizable energy ratio. The best-fit prediction equation in this experiment can be used to accurately estimate the metabolizable energy value of double-low rapeseed cake fed to growing pigs under practical conditions.The study was conducted to develop and validate an equation to predict the metabolizable energy (ME) of double-low rapeseed cakes (DLRSC) for growing pigs based on their chemical compositions. In Experiment 1, 66 growing pigs (initial body weight 36.6 ± 4.1 kg) were allotted randomly to a completely randomized design with 11 diets. The diets included a corn–soybean meal basal diet and 10 test diets containing 19.22% DLRSC supplemented at the expense of corn, soybean meal, and lysine. Neutral detergent fiber (NDF), crude fiber (CF), and gross energy (GE) were the best predictors to determine ME. The best-fit prediction equation of ME (MJ/kg) was ME = 9.33 − 0.09 × NDF − 0.25 × CF + 0.59 × GE (R2 = 0.93). In Experiment 2, a total of 144 growing pigs (initial body weight 29.7 ± 2.7 kg), with six pigs per pen and six pens per treatment, were assigned randomly to four treatments in a completely randomized block design for a 28-day feeding trial. A corn–soybean meal basal diet was prepared, and three additional diets were formulated by adding 7%, 14%, and 21% DLRSC to the basal diet at the expense of soybean meal. All diets were formulated to provide equal standardized ileal digestibility (SID) Lys/ME ratio and SID essential amino acids/SID Lys ratio. Increasing dietary levels of DLRSC had no effect on average daily feed intake, average daily gain, and feed-to-gain ratio. The caloric efficiency of ME (31.83, 32.44, 31.95, and 32.69 MJ/kg, respectively) was not changed by increasing the dietary concentration of DLRSC. Increasing dietary levels of DLRSC linearly reduced (p < 0.05) the concentrations of triiodothyronine and tetraiodothyronine in serum, as well as apparent total tract digestibility of DM, GE, crude protein, acid detergent fiber, and organic matter of the diet. In conclusion, the ME prediction equation obtained in Experiment 1 accurately estimates the ME value of DLRSC fed to growing pigs.

Detection of Blackleg Resistance Gene Rlm1 in Double-Low Rapeseed Accessions from Sichuan Province, by Kompetitive Allele-Specific PCR.

Blackleg is a serious disease in Brassica plants, causing moderate to severe yield losses in rapeseed worldwide. Although China has not suffered from this disease yet (more aggressive Leptosphaeria maculans is not present yet), it is crucial to take provisions in breeding for disease resistance to have excellent blackleg-resistant cultivars already in the fields or in the breeding pipeline. The most efficient strategy for controlling this disease is breeding plants with identified resistance genes. We selected 135 rapeseed accessions in Sichuan, including 30 parental materials and 105 hybrids, and we determined their glucosinolate and erucic acid content and confirmed 17 double-low materials. A recently developed single-nucleotide polymorphism (SNP) marker, SNP_208, was used to genotype allelic Rlm1/rlm1 on chromosome A07, and 87 AvrLm1-resistant materials. Combined with the above-mentioned seed quality data, we identified 11 AvrLm1-resistant double-low rapeseed accessions, including nine parental materials and two hybrids. This study lays the foundation of specific R gene-oriented breeding, in the case that the aggressive Leptosphaeria maculans invades and establishes in China in the future and a robust and less labor consuming method to identify resistance in canola germplasm.

Nutritive values of double-low rapeseed expellers and rapeseed meal with or without supplementation of multi-enzyme in pigs

Two experiments were conducted to evaluate the effects of adding multi-enzyme on the available energy concentration and standardized ileal digestibility (SID) of amino acids of double-low rapeseed expellers (RSE) and rapeseed meal (RSM) fed to growing pigs. In Experiment 1, a total of 36 growing barrows were fed six diets in a replicated 3 × 2 factorial design. Diets included a corn–soybean meal basal diet, RSE diet, and RSM diet with or without multi-enzyme (1000 U g−1 of cellulase, 10 000 U g−1 of xylanase, 2000 U g−1 of glucanase, and 10 000 U g−1 of protease). In Experiment 2, a total of 30 crossbred pigs were randomly allotted to five diets consisting of a nitrogen-free diet and four cornstarch-based diets containing RSE or RSM with or without multi-enzyme. Multi-enzyme supplementation significantly improved (P &lt; 0.05) the metabolizable energy (ME) value and apparent total tract digestibility (ATTD) of ether extract, neutral detergent fiber, and acid detergent fiber, and it tended to increase (P &lt; 0.10) the ATTD of gross energy and digestible energy in ingredients. With the exception of phenylalanine, multi-enzyme supplementation increased (P &lt; 0.05) the SID of crude protein (CP) and all amino acids (AA) in ingredients. Multi-enzyme supplementation enhanced fiber degradation and increased the ME value and SID of CP as well as most AA in double-low rapeseed co-products fed to pigs.

An increase in dietary lipid content from different forms of double-low rapeseed reduces enteric methane emission in Datong yaks on the Qinghai-Tibetan Plateau.

Enteric methane (CH4 ) emission in cattle generally decreases by approximately 1g/g dry matter intake (DMI) with an increase in dietary lipids of 10g/kg dry matter (DM). The effect of dietary lipids on CH4 emission in yaks has not been reported and is the subject of this study. Four Datong yaks were used in a 4×4 Latin-square design in which the four treatments included restricted intakes of double-low rapeseed differing in form and lipid (ether extract-EE) content: (a) rapeseed meal (EE 32.6g/kg DM); (b) rapeseed meal and rapeseed cake (EE 45.8g/kg DM); (c) rapeseed meal and whole cracked rapeseed (EE 54.5g/kg DM) and (d) rapeseed meal and rapeseed oil (EE 62.7g/kg DM). The digestibility of feed components did not differ among treatments. The ruminal total volatile fatty acids (p=.082) and acetic acid (p=.062) concentrations tended to be lowest in yaks consuming the diet with highest lipid content. In addition, CH4 production was lowest in this group (p=.004), and declined by 1.75g/g DMI per 10g/kg DM reduction in dietary lipid content, a rate substantially faster than in cattle.

Concentration of metabolizable energy and digestibility of amino acids in Chinese produced dehulled double-low rapeseed expellers and non-dehulled double-low rapeseed co-products fed to growing-finishing pigs

Two experiments were conducted to determine and compare the digestible energy (DE), metabolizable energy (ME) and the coefficients of standardized ileal digestibility (CSID) of crude protein (CP) and amino acids (AA) in two sources of dehulled rapeseed expellers (RSE-DH1 and RSE-DH2), conventional rapeseed expellers (RSE-CV), cold-pressed rapeseed expellers (RSE-CP) and rapeseed meal (RSM) produced by Chinese double-low rapeseed fed to growing-finishing pigs. In experiment 1, 36 growing pigs [initial body weight (BW): 37.7±4.8kg] were randomly allotted to one of six diets (n=6) including a corn-soybean meal basal diet and five rapeseed co-product test diets. The test diets contained 194.8g/kg each of the five double-low rapeseed co-products added at the expense of corn and soybean meal in the basal diet. In experiment 2, six growing barrows (initial BW: 69.4±4.4kg) fitted with a T-cannula in the distal ileum were allotted to a 6×6 Latin square design with 6 periods and 6 diets. Diets included one N-free diet and five test diets which contained 400g/kg RSE or RSM as the only source of CP and AA. On an as fed basis, dehulled RSE samples (RSE-DH1 and RSE-DH2) contained the lowest neutral detergent fiber and acid detergent fiber among rapeseed co-product samples. Dehulled RSE samples had greater lysine concentration than non-dehulled RSE and RSM. The coefficient of apparent total tract ileal digestibility (CATTD) of gross energy (GE) in RSE-DH1 (0.822) was greater (P<0.05) than that in RSE-CV (0.700) and RSM (0.655), but the CATTD of GE did not differ among RSE-DH1, RSE-DH2 (0.782) and RSE-CP (0.722). On an as-fed basis, the ME value was greater (P<0.05) in dehulled RSE (14.5MJ/kg) than RSE-CV (12.2MJ/kg) and RSM (10.4MJ/kg). The RSE-DH1 (9.72MJ/kg) and RSE-DH2 (9.33MJ/kg) contained greater (P<0.05) calculated net energy value than RSE-CP (8.03MJ/kg), RSE-CV (7.84MJ/kg) and RSM (5.66MJ/kg). With the exception of phenylalanine and valine, the CSID of CP and all AA in dehulled RSE was greater (P<0.05) than that in RSE-CV and RSM. The CSID of CP and most of AA in RSE-DH1 was greater (P<0.05) than that in RSE-CP. In conclusion, compared with non-dehulled rapeseed co-products, dehulled double-low rapeseed expellers may be a better energy and protein source for pigs considering its greater ME value and CSID of AA.

Investigations of the nutritive value of meals of double-low rapeseed and its influence on growth performance of broiler chickens

Four experiments were carried out to study the possible differences in metabolizable energy (ME) of meals (RSM) or expeller meals (RSE) from double-low rapeseed (Expt. 1), the influence of processing on ME (Expt. 2) and on relative phosphorus (P) bioavailability (Expt. 3) in RSM, and effect of RSM inclusion on growth performance of broilers (Expt. 4). For Expt. 1, diets with 300 g/kg RSM from 11 RSM and 4 RSE varieties were fed to broilers from d 14 to 21, with excreta collection on d 19 to 21. Each treatment had 8 replicates and 3 birds per replicate. Energy metabolizability of RSM of a specialized high glucosinolate variety (V275OL) was greater (P < 0.05) than all the other varieties. In Expt. 2, two RSM varieties were processed with mild or conventional processing condition. There were no variety effects on ME, but ME and MEn were greater (P < 0.01) for RSM processed by mild processing condition. In Expt. 3, P bioavailability of RSM was determined, relative to MSP, using growth performance and tibia ash as responses. Phosphorus relative bioavailability values were greater (P < 0.05) in RSM of DK Cabernet variety processed using the mild processing condition. In Expt. 4, two RSM varieties were added to wheat-soybean meal-based diet at the rates of 50, 100, 150, or 200 g/kg and fed to broilers from d 0 to 42. Inclusion of 150 and 200 g/kg of RSM resulted in reduced weight gain and increased feed conversion ratio (FCR) compared (P < 0.01) with the lower inclusion levels during the starter phase. For the entire trial (d 0 to 42), weight gain was greater (P < 0.01) for birds receiving diets with RSM from PR46W21 variety. It was concluded from the experiments that apart from the residual ether extract content, variety differences had no impact on ME of RSM, conventional processing reduced ME and relative bio-availability of P; and that the maximum level of RSM inclusion depends on maximum growth performance level desired.

Effectiveness of health benefit of double-low rapeseed oil and its high oil content breeding

Effectiveness of health benefit of double-low rapeseed oil and its high oil content breeding

Determination of the energy content and amino acid digestibility of double-low rapeseed cakes fed to growing pigs

Two experiments were conducted to determine the digestible (DE) and metabolizable energy (ME) content as well as the apparent (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in double-low rapeseed cakes (DLRSC) fed to growing pigs. In Exp. 1, 66 growing pigs (initial body weight (BW): 36.6±4.1kg) were randomly allotted to 1 of 11 diets (n=6) including a corn-soybean meal basal diet and 10 DLRSC test diets. The basal diet was formulated using corn and soybean meal while the DLRSC test diets contained 192.2g/kg DLRSC added at the expense of the corn, soybean meal and lysine. In Exp. 2, 9 growing barrows (initial BW: 29.7±3.1kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a 6×9 Youden square design with 6 periods and 9 diets. The diets included a N-free diet containing 689g/kg cornstarch and 200g/kg sucrose and 8 test diets which were formulated to include 400g/kg of one of the DLRSC samples. The chemical composition of the 10 DLRSC samples varied considerably especially for aNDF, ADF, calcium, phosphorus and total glucosinolates. The DLRSC samples had a similar AA composition (CV<10%) with the exception of lysine (CV=23.5%). The DE and ME content differed (P<0.01) among the 10 DLRSC samples. On a dry matter basis, the DE (mean 14.51MJ/kg) and ME content (mean 13.08MJ/kg) varied from 12.64 to 15.77MJ/kg and 11.93 to 14.41MJ/kg, respectively. The apparent total tract digestibility coefficient of gross energy averaged 0.686 ranging from 0.596 to 0.728. The results of Exp. 2 showed the AID of CP and lysine averaged 0.65 and 0.68, respectively. For the indispensible AA in DLRSC, the SID of arginine (mean 0.883) and methionine (mean 0.897) were relatively high. In contrast, the SID of threonine (mean 0.706) and Lys (0.704) were relatively low. The SID of CP and lysine ranged from 0.652 to 0.806 and 0.554 to 0.862, respectively. In conclusion, there were great differences in the chemical composition, energy content and the SID and AID of CP and AA among DLRSC samples. These differences in chemical composition especially the ether extract, fiber and total glucosinolates content may be responsible for the variability often observed in the nutritional value of DLRSC.

Chemical composition, energy and amino acid digestibility in double-low rapeseed meal fed to growing pigs.

BackgroundThe nutritional value of rapeseed meal may be variable due to the variation of its chemical composition. And a precise understanding of the nutritional value of an ingredient is beneficial for the accurate diet formulation and reduction of feed costs. This study was conducted to determine the chemical composition, digestible energy (DE) and metabolizable energy (ME) content, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) for growing pigs. Thirteen solvent-extracted double-low rapeseed meal (DLRSM) samples were obtained from the main double-low rapeseed producing areas in China.MethodsThe DE and ME contents of the 13 DLRSM samples were measured in growing pigs (six pigs per DLRSM sample, average initial body weight (BW) = 48.3 kg). The AID and SID of AA of 10 DLRSM samples were determined in 12 crossbred barrows (average initial BW = 35.3 kg) by using two 6 × 6 Latin square designs. Each Latin square comprised one N-free diet and 5 DLRSM test diets.ResultsThe chemical composition of DLRSM varied among samples, and the coefficient of variation was greater than 10 % for ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca), and total glucosinolates. The AA content of DLRSM varied among samples especially for lysine (Lys) and methionine (Met). On a dry matter (DM) basis, the apparent total tract digestibility (ATTD) of gross energy (GE), the DE and ME and the ME:DE ratio of DLRSM averaged 62.39 %, 2862 kcal/kg and 2723 kcal/kg, and 94.95 %, respectively. The mean value of SID of Lys was 70.52 % which varied from 66.54–76.54 %. The SID of crude protein (CP), Met, and threonine (Thr) averaged 72.81 %, 82.41 %, and 69.76 %, respectively.ConclusionsThere was great variability in chemical composition especially in the concentration of EE, NDF and ADF, but no significant differences in energy content of the DLRSM samples were observed. In addition, the AID and SID of all AA were relatively similar among DLRSM samples except for that of Lys.

Long-Term No-Tillage Direct Seeding Mode for Water-Saving and Drought-Resistance Rice Production in Rice-Rapeseed Rotation System

To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistance rice (WDR) variety and a double low rapeseed variety as materials was conducted under no-tillage direct seeding (NTDS) mode and conventional tillage direct seeding (CTDS) mode for four years, using the CTDS mode as the control. Compared with the CTDS mode, the actual rice yield of WDR decreased by 8.10% at the first year, whereas the plant height, spikelet number per panicle, spikelet fertility, 1000-grain weight, grain yield, actual yield, and harvest index increased with no-tillage years, which led to the actual yield increase by 6.49% at the fourth year. Correlation analysis showed that the panicle length was significantly related to the actual yield of WDR. Compared with the CTDS mode in terms of the soil properties, the pH value of the NTDS mode decreased every year, whereas the contents of soil organic matter and total N of the NTDS mode increased. In the 0–5 cm layer of the NTDS mode, the soil bulk decreased, whereas the contents of soil organic matter, total N, and available N increased. In the 5–20 cm layer of the NTDS mode, the available N and K decreased, whereas the soil bulk, contents of soil organic matter, and total N increased. In summary, the NTDS mode increased the rice yield, and could improve the paddy soil fertility of the top layer.

Aqueous Enzymatic Extraction of Rapeseed Oil and Protein from Dehulled Cold-pressed Double-low Rapeseed Cake

Abstract The oil and protein of dehulled cold-pressed double-low rapeseed cake was extracted by an aqueous enzymatic process. The rapeseed cake was treated by the chosen combined enzymes of Viscozyme L and Alcalase 2.4L (VLA,1:1,w/w). Preliminary experiments and Response Surface Methodology (RSM) were used to study the effects of enzyme concentration, incubation time and water-to-cake ratio on the extraction yield of oil and protein. This is how the desirable conditions were obtained. Transmissive electron microscope photo showed that after cold-pressing the cell structure of rapeseed was partly damaged while dehulling had little effect on the cell structure of rapeseed. In RSM experiments water-to-cake ratio showed significant effects on the extraction of oil and protein (P&lt;0.05),while incubation time only showed significant effects on protein yield (P&lt;0.05).The desirable conditions were as follows: 1.0% concentration (w/w) of VLA; water-to-cake ratio(w/w),6:1; 80 min incubation time. Under this condition, the extraction yield of protein and oil were 82.10% and 71.89%, respectively. Through combining both the cold-press and the aqueous enzymatic processes together, the total oil yield reached 91.6%, which is higher than the normal cold-press process or the aqueous enzymatic extraction process alone.

Evaluation of extruded or unextruded double-low rapeseed meal and multienzymes preparation in pigs nutrition during the finishing phase of production

The aim of this study was to compare the effects of extruded or non-extruded double-low rapeseed meal (DL-RSM) and multienzyme preparation on performance, nutrient digestibility, immune function and antioxidant status of the finishing pigs. Forty-eight pigs (Duroc×Landrace×Yorkshire) with an average weight of 62 kg were randomly divided into four groups with three replicates according to gender. Four diets were formulated to meet NRC (1998) nutrient requirements. Diet 1, based on the corn and soybean meal (SBM), was used as control. Diet 2 used 13% DL-RSM instead of the 11% SBM used in the Diet 1. Diet 3 used 13% extruded double-low rapeseed meal (E-DL-RSM) instead of 11% SBM, and Diet 4 0.03% multienzyme preparation was supplemented in Diet 3. The results showed that replacement of 11% SBM by 13% DL-RSM had no negative effects on performance and nutrient digestibility for finishing pigs. Extrusion and multienzyme preparation also had no beneficial effects on pig performance. However, the concentration of immunoglobulin G (IgG) in serum of DL-RSM treatment was lower (P<0.05) than that of the control, but it increased to the level of control in the treatment of extrusion combined with multienzyme preparation. The diet containing E-DL-RSM combined with multienzyme preparation significantly decreased the malondialdehyde (MDA) content (P<0.05) in serum. It was concluded that DL-RSM was an acceptable alternative to SBM as part of a protein supplement for finishing pig diets. In addition, extrusion and multienzymes preparation were not economically applied in the current study because of their extra cost.

Some characteristics and functional properties of rapeseed protein prepared by ultrasonication, ultrafiltration and isoelectric precipitation

The presence of complex protein constituents and difficulties in extracting protein from rapeseed meal limit the application of rapeseed protein in food processing. However, double-low rapeseed (low erucic acid, low glucosinolate) protein is a type of complete protein that is of potential use in the food industry. In this study the characteristics and functional properties of rapeseed protein prepared by ultrasonic-assisted extraction, ultrafiltration and isoelectric precipitation were analysed and compared with those of soybean protein. The extraction efficiency with the ultrasonic-assisted method was significantly higher than that obtained with the traditional method. Ultrafiltration and isoelectric precipitation yielded three different proteins: ultrafiltered protein RPs and precipitated proteins RP5.8 and RP3.6. Chromatographic separation of RPs resulted in four fractions: RPsI, RPsII, RPsIII and RPsIV. The distribution of the isoelectric point of rapeseed protein was investigated by two-dimensional electrophoresis. The amino acid composition of RPs renders it suitable for human consumption. The hydrophobic/hydrophilic amino acid ratio of rapeseed protein was higher than that of soybean protein. The functional properties (oil adsorption ability, emulsifying capacity, foaming capacity and foam stability) of RPs, RP5.8 and RP3.6 were found to be better than those of soybean protein. Ultrasonication and ultrafiltration were significantly better than the traditional method of rapeseed protein extraction. The ultrafiltered rapeseed protein RPs had superior functional properties. The results of this study provide useful indicators for rapeseed protein as a potential replacement for other proteins.

Effects of Plant Residue, Root Exudate and Juvenile Plants of Rapeseed (Brassica napus L.) on the Germination, Growth, Yield, and Quality of Subsequent Crops in Successive and Rotational Cropping Systems

Double-low rapeseed cultivars that produce no erucic acid and have only a small amount of glucosinolates are widely used. However, the roots in mature plant residue and leaves and roots of these seedlings still contain a large amount of biologically active glucosinolates, and it is important to clarify the effect of rapeseed cultivation on the subsequent crops. We analyzed the biological activities of the tissues of double-low cultivar at harvest. The laboratory bioassays revealed that the seeds and roots of mature rapeseed plants contained some autotoxic components that were volatile and water-soluble. We also analyzed the effects of root exudates from growing rapeseed plants on rapeseed germination and growth using the stair-step method and found that the root exudates were autotoxic. In the field, we investigated the allelopathic effects of rapeseed plants on the growth, yield, and quality of the subsequent sunflower plant in the same field. The growth, yield and thousand kernel weight of sunflower were reduced by the preceding cultivation of rapeseed. There were many spontaneously germinated juvenile rapeseed plants in the sunflower field preceded by rapeseed cultivation. Analysis of the plant and soil nitrogen (N) indicated that the growth reduction of sunflower was not caused by the competition for N with the spontaneously germinated juvenile rapeseed plants. The main factors responsible for poor sunflower growth under field after the cultivation of rapeseed were suggested to be some non-volatile, water-soluble components produced by the roots of the spontaneously germinated juvenile rapeseed.

Effects of enzyme addition on the nutritive value of broiler diets containing hulled or dehulled Chinese double‐low rapeseed meals

An in vitro and a feeding trial was conducted to investigate the effect of fibre-degrading enzymes A (xylanase + β-glucanase), B (xylanase) and C (xylanase + cellulase) on the nutritive value of broiler diets containing either hulled (22.5% and 23.5% for 4–21 days and 22–42 days of age, respectively) or dehulled (20% and 21.5%) Chinese double-low rapeseed meals (DLRM). Overall, in vitro digestibility of dry matter (DM) or neutral digestibility fibre (NDF) did not differ (p > 0.05) because of meal types; both crude protein (CP) and NDF digestibility was improved (p < 0.05) because of addition of enzymes B or C either to hulled or dehulled DLRM diets. Birds fed dehulled DLRM diets had a higher (p < 0.05) growth rate, feed efficiency and lower (p < 0.05) feed intake than those fed hulled DLRM diets during the overall phase. Enzyme C addition to dehulled DLRM diets resulted in improved (p < 0.05) growth rate and feed efficiency during 4–21 days of age. Enzymes A and B addition elicited a positive response in feed intake and weight gain (p < 0.05), respectively, but did not affect (p > 0.05) feed efficiency. It would appear that the nutritive value of broiler diets containing Chinese DLRM could be improved by appropriate xylanase-based enzymes. Responses of broilers to fibre-degrading enzymes could be highlighted by hull removal of fed DLRM.

Effects of minimal temperatures on low-linolenic rapeseed oil fatty-acid composition

Rapeseed oil is rich in alpha-linolenic acid (C18:3) and has a low content in saturated fatty acids. It is therefore considered as a very healthy edible oil. However, its high polyunsaturated fatty acid content makes it sensitive to temperature oxidation and therefore not suitable for deep-frying. Low-linolenic varieties with C18:3 content lower than 3.5% have been bred, but a large variability of alpha-linolenic acid content has been often observed in agricultural production of these new lines. Identifying factors affecting the fatty acid profile of oilseed rape should make it possible to produce rapeseed with alpha-linolenic acid content lower than 2.5% and therefore more suitable for frying and other uses in the food industry. Fatty acid composition is affected by environmental conditions, temperature being the main factor. Previous works showed that for conventional double-low rapeseed varieties, low minimal temperatures during the 60 days following the onset of flowering were related to higher alpha-linolenic acid contents. Monitoring the fatty acid profile in low-linolenic varieties from the beginning of seed filling to full maturity showed that alpha-linolenic acid synthesis occurred mainly between 550 and 850 degree-days (base 0 °C) after the onset of flowering, that is during the 20 first days of seed filling in Swiss conditions, i.e. 41–60 days after the onset of flowering. During this period, the determination coefficient of a second order regression between final alpha-linolenic acid (C18:3) content and minimal daily temperature was even better, with R 2 = 0.87. A significant positive relation was also found for the regression between minimal temperature and oleic acid (C18:1) content for the cultivar Splendor ( R 2 = 0.77) but no correlation could evidence a relation between temperature and linoleic acid (C18:2) content. An easier way to show the relationship between linolenic acid content and minimal temperatures is based on the assumption that fatty acid desaturases regulated by temperature are active at low temperatures only. It consists in counting how many times during this period daily minimal temperature reaches a minimal threshold temperature of 13 °C. The relationship between final alpha-linolenic acid content and the number of days with minimal temperature below 13 °C is as good as the one presented before, i.e. with a determination coefficient, R 2 = 0.85. This simple model could be used to determine the growing areas with low linolenic acid content.

Xylanase Supplementation Improved Digestibility and Performance of Growing Pigs Fed Chinese Double-low Rapeseed Meal Inclusion Diets: In vitro and In vivo Studies

An in vitro and a feeding trial were conducted to investigate the effect of xylanase supplementation on the feeding value of growing pig diets containing high proportions of Chinese double-low rapeseed meals (DLRM). Seven diets were formulated to meet NRC (1998) nutrient requirements. Diet 1 based on corn-soybean meal was used as positive control 1, and diet 2, a practical diet which incorporated a conventional level of Chinese DLRM (60 g/kg diet), as positive control 2. Diet 3 contained a higher level of DLRM (100 g/kg diet) as the negative control. Diet 3 plus xylanase at 0.10, 0.25, 0.50 and 0.70 g/kg diet created diets 4, 5, 6 and 7, respectively. The seven diets were incubated in triplicate with the in vitro two-stage enzyme incubation method to predict responses of diets to xylanase in terms of digestibility of dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF). In vitro, the negative control had the lowest CP and NDF digestibility. Both DM and CP digestibility were increased (p 0.90, p<0.05) between the activity concentration of the enzyme when transformed into its logarithmic value and in vitro digestibility coefficients of DM, CP or NDF. In the feeding trial, 112 crossbred pigs were randomly assigned to seven dietary treatments with 16 replicate pens of one pig each. An obvious dose effect on growth rate was observed (r 2 = 0.79, p<0.05) within the inclusion levels of xylanase. Compared with the negative control, xylanase addition at 0.70 g/kg diet resulted in significantly increased ADG (878 g/d vs. 828 g/d, p<0.05), and a tendency towards improved growth rate (868 g/d vs. 828 g/d, p = 0.10) was also observed following the inclusion of xylanase at 0.50 g/kg diet. It would appear that the nutrient utilization of corn and Chinese DLRM diets by pigs could be enhanced by an appropriate amount of xylanase addition. The in vitro and in vivo results suggested that the in vitro incubation method is feasible for predicting responses of pigs to exogenous enzymes and identifying those preparations that possess potential for improvement of the nutritive values of feedstuffs. (Key Words : Chinese DLRM, Digestibility, Performance, Pigs, Xylanase)

Screening of nutrient digestibilities and intestinal pathologies in Atlantic salmon, Salmo salar, fed diets with legumes, oilseeds, or cereals

Ten different plant protein and/or starch sources were studied in a 5-week experiment with triplicate groups of 0.7-kg Atlantic salmon in seawater, pre-adapted to a diet with fish meal, faba beans, sunflower cake, and wheat gluten as sources of protein and starch. The experimental ingredients were corn gluten, defatted soybean, defatted sunflower, dehulled lupin, defatted double-low rapeseed, whole field pea, whole and dehulled faba bean, whole wheat and naked oat, tested one at a time (14–24% inclusion). The diets were balanced by addition of pure wheat starch and/or pure cellulose, to obtain equal macro nutrient compositions. The control diet consisted of fish meal, wheat starch, cellulose and fish oil. The results showed reduced faecal dry matter content in fish fed the soybean diet and to a lesser extent in those fed the sunflower, lupin and rapeseed diets. Diets containing lupin and rapeseed resulted in a moderate increase in the viscosity of the digesta, while diets with wheat and oat increased viscosity of digesta more. Apparent digestibility of lipid decreased linearly with increasing dietary cellulose level. A significant reduction in the digestibility of crude protein was seen for the soybean, sunflower, rapeseed and oat diets, reflecting reduced digestibilities of most amino acids. The salmon fed the corn gluten, lupin, pea, bean and wheat diets had protein digestibilities comparable to the control group. The digestibility of phosphorus was highest for salmon fed the rapeseed diet and lowest for fish fed the oat diet. Faecal excretion of sodium was highly elevated for salmon fed the soybean diet, and moderately elevated for fish fed the corn gluten and sunflower diets. Faecal excretion of zinc was elevated in the fish fed the oat diet. None of these observations were significantly related to the dietary concentration of phytic acid. A histological examination of the stomach, mid- and distal intestine of all groups showed no other irregularities than enteritis in the distal intestine of salmon fed soybean meal. The present study demonstrated a potential for several plant ingredients, such as field pea and faba bean, partly replacing high-quality fish meal in diets for Atlantic salmon, based on nutrient digestibilities and absence of pathologies in the stomach and intestine.

Responses of non‐starch polysaccharide‐degrading enzymes on digestibility and performance of growing pigs fed a diet based on corn, soya bean meal and Chinese double‐low rapeseed meal

This study was conducted to investigate the effect of two distinct enzyme preparations on nutrients' digestibility and growth performance of growing pigs fed diets based on corn, soya bean meal and Chinese double-low rapeseed meal (DLRM). The two enzyme preparations were Enzyme R, a preparation extracted from fermentation of a non-GMO fungus Penicillum funiculosum, developed for multi-grain and multi-animal species; and Enzyme P, a xylanase preparation from Trichoderma longibrachiatum, for pigs fed corn-based diets only. Both enzymes were tested at 0, 0.25 and 0.50 g/kg feed using 70 crossbred male pigs (Large Yorkshire x Landrace) in five dietary treatments and seven replicates in each treatment, for growth period from 27 to 68 kg live weight in 49 days. Results showed that the supplementation of both enzymes (1) increased total-tract digestibility of dietary energy from 77.5% (control) to 81.4% (Enzyme R, p < 0.05) and 81.9% (Enzyme P, p < 0.05); of neutral detergent fibre from 41.0% (control) to 57.8% (Enzyme R, p < 0.05) and 60.0% (Enzyme P, p < 0.05); (2) improved average daily gain from 786 g (control) to 829 g (Enzyme R, p < 0.05) and 846 g (Enzyme P, p < 0.05); and numerical increases in feed intake from 1.96 kg/pig/day (control) to 2.01 (Enzyme R) and 2.00 (p > 0.05) and feed conversion ratio from 2.50 (control) to 2.42 (Enzyme R) and 2.36 (Enzyme P, p < 0.05); (3) there was a dose response but no significant differences were observed in enzyme efficacy between the two enzyme preparations. The present study demonstrated beneficial effects of applying xylanase-based enzymes to improve feeding values of pig diets based on corn, soya bean meal and DLRM.

Effects of Processing Methods and Variety of Rapeseed Meal on Ruminal and Post Ruminal Amino Acids Digestibility

The objective of this study was to determine the effects of processing method and rapeseed variety on ruminal and intestinal protein digestibility of rapeseed meal in steers. Intestinal amino acid digestibility was assessed with an in situ ruminal incubation and precision-fed rooster bioassay. In this experiment one traditional rapeseed meal sample (sample A, prepress extraction) and three double low rapeseed meal samples (sample B, prepress extraction, sample C, screw press and sample D, low temperature press) were placed in polyester bags(8 cm×12 cm) and suspended in the ventral rumen of steers for 16 h. The residues of in situ incubations were intubated to roosters. Total excreta were collected for 48 h after incubation and then desiccated and amino acid concentrations were determined. Results showed that in ruminal incubation the degradation rate of amino acid and crude protein was higher for traditional rapeseed meal sample A than for double low rapeseed meal sample B, but was much lower than for double low sample C and D. In the group of double low rapeseed meal samples, sample D processed by low temperature press had the highest degradation rate of amino acids in the rumen. For all amino acids, the digestibility of the residual protein as measured by the precision- fed rooster bioassay tended to be lower for sample B than for sample A, which had the same processing method with sample B, and in the group of double low rapeseed meals, sample B had similar digestibility of amino acid in residual protein to sample D and higher than that of sample C. However, although the total amino acid availability involving the digestibility of amino acids in the rumen and rooster bioassay of double low rapeseed meal sample D (low temperature press) was higher than those of the other three samples by 7 to 9 percent, there were no significant differences. Results indicated that processing method markedly affected ruminal and post ruminal amino acid digestibility of rapeseed meal when the temperature exceeded 110°C. Rapeseed meal that had a high content of fiber was not suitable for dry heat treatment at higher temperatures or the amino acids digestibility in rumen and total availability of amino acids could be reduced. Results also suggested the variety of rapeseed meal had no significant effect on the digestibility and availability of amino acids. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 6 : 802-806)