Low Erucic Acid Research Articles

SUBSTITUTION OF RAPESEED MEAL FOR SOYBEAN MEAL AS A SOURCE OF PROTEIN FOR LACTATING COWS

Sixteen lactating Holstein cows were randomly assigned to treatment sequences in a 4 × 4 changeover experiment. Experimental periods were 28 days in length separated by 7 days for changeover. Cows were fed corn silage free choice and gradually increasing amounts of one of four dairy concentrates containing 0, 11, 22, or 34% rapeseed meal (RSM) of a Canadian, experimental, low glucosinolate–low erucic acid variety. Concentrate intake (kg dry matter/day), milk yield (kg/day) and body weight change (kg/28 days) were 8.45a, 8.71a, 8.37a and 7.17b; 24.40a, 24.03ab, 22.92bc and 21.96c and 7.6b, 22.4b, 13.0ab, and 3.0b for 0, 11, 22 and 34% RSM mixtures, respectively. There was no influence of treatment on milk composition. Ration dry matter (DM) and nitrogen digestibilities declined (P < 0.05) as the RSM in the concentrate mixture increased. The amount of nitrogen excreted in the urine was greatest for cows fed 0% RSM and least for cows fed 34% RSM. Cows fed concentrate mixtures containing 34% RSM had a lower blood thyroxine level than others (P < 0.05), but RSM-containing concentrates had no apparent effect on the conversion of thyroxine to triiodothyronine. Results of the trial indicated that this experimental variety of RSM had no detrimental effect on concentrate intake, DM digestibility, milk composition or thyroid hormone metabolism when included at levels up to 22% in the concentrate mixture. However, milk yield and apparent digestibility of ration nitrogen were decreased (P < 0.05) by the 22% RSM mixture. It was not certain from the current findings whether the depression in digestibility was due largely to the high oil content of the meal or due to the higher fiber content of the RSM-supplemented rations.

Fatty haemorrhagic liver syndrome in laying hens on diets supplemented with rapeseed products

Livers of laying hens of Hy-Line No 934E on low erucic acid rapeseed meals and rapeseed oil were studied. Gross lesions in the livers of hens on experimental diets were moderate to severe fatty degeneration, focal necrosis and moderate to severe haemorrhage. Histological examination revealed oedematous foci and lysis of hepatocytes along with large amounts of lipid droplets in the necrotic lesions. Necrotic lesions were not always associated with large haemorrhages. Connective tissue infiltration of older degenerative and haemorrhagic lesions was not extensive. Abdominal haemorrhage from livers occurred when extensive necrosis in the form of hepatocyte lysis and some vascular changes were present, suggesting hepatocytic degeneration caused by toxic products or their metabolites present in rapeseed by-products.

EVALUATION OF LOW GLUCOSINOLATE — LOW ERUCIC ACID RAPESEED MEALS AS PROTEIN SUPPLEMENTS FOR YOUNG GROWING PIGS, INCLUDING EFFECTS ON BLOOD SERUM CONSTITUENTS

Forty-nine 4- to 5-wk-old pigs, averaging 7 kg in weight, were allotted to seven treatment groups. Rapeseed meals (RSM) from two cultivars of double-low (low glucosinolate-low erucic acid) Brassica napus rapeseed processed at one plant, one of the same cultivars processed at a second plant, and a low erucic acid B. campestris cv. Span were compared as partial or complete replacements (up to 22% of the diet) for soybean meal (SBM) in diets of starting–growing pigs. Overall results for feed intake, daily gain and efficiency of feed conversion indicated that RSM from a double-low cultivar (now licensed as Tower) may completely replace SBM in diets for starting–growing pigs with no depression in performance. Results from un unlicensed cultivar (1788) were inconsistent, with differences possibly associated with residual hexane in one sample of meal. Digestible energy and nitrogen, metabolizable energy and nitrogen retention did not differ between treatments. A profile of 14 blood serum constituents was obtained from individual pigs 3 and 9 wk after the start of the experiment. Thyroxine (T4) values were lower (P < 0.05) for all treatments when RSM was completely substituted for SBM. Protein-bound iodine values did not differ significantly between treatments but followed the same trends as T4. Results suggest that all RSM samples were goitrogenic to some degree. Blood serum constituents that correlated with average daily gain at [Formula: see text] were calcium, total protein, albumin, albumin:globulin ratio and lactate dehydrogenase. The results suggest that RSM from low glucosinolate–low erucic acid rapeseed, when it becomes commercially available, may be fed at higher levels than currently recommended.

UTILIZATION OF FULL-FAT RAPESEED AND RAPESEED MEALS IN RATIONS FOR BROILER CHICKS

Two experiments were conducted to assess the use of full-fat rapeseed (RS) or rapeseed meal (RSM) in rations for broiler chicks. The first experiment included comparisons between Span (a low erucic acid variety) and Bronowski (a low glucosinolate variety) RS and the effects of addition of two types of fat (crude Span rapeseed oil and stabilized tallow) in the rations used. Parameters studied included rate of gain, feed conversion, size of thyroids, livers and hearts and composition of carcasses, hearts and livers. The second experiment studied the effects of protein level and amino acid supplementation on nutrient retention in broiler chicks fed Span RS. Inclusion of 20% raw Span or Bronowski RS in broiler rations resulted in depressed weight gain and feed conversion, increased thyroid size and production of leaner carcasses as compared to those obtained when a control ration or rations containing autoclaved RS were fed. Raw Bronowski RS resulted in superior weight gain and feed conversion as compared to raw Span RS. Use of 12% Span RSM with either RSO or stabilized tallow or 12% Bronowski RSM with RSO gave performance similar to that of chicks fed the control ration. When stabilized tallow was used with Bronowski RSM, performance was improved over that obtained with the control ration. The use of full-fat RS, RSM or RSO did not cause fat accumulation in the hearts and livers of chicks. The percentage of dry matter, fat and energy retained by chicks fed the control ration was significantly higher than in chicks fed raw or autoclaved RS. Protein retention was not affected by inclusion of RS in the rations.

The limiting effect of plant size at inflorescence initiation on subsequent growth and yield of oilseed rape (Brassica napus)

SUMMARYA substantial loss in yield usually occurs when oilseed rape is sown later than mid-September. Field experiments in 1972–3 tested whether this is because all plants, irrespective of size, initiate inflorescences during the winter, thus restricting the eventual size of the leaf canopy and the yield potential of late-sown plants, which are still very small when the change to the reproductive phase occurs.Sowing a standard winter variety, Victor, from mid-August to mid-October resulted in initiation occurring from late October to February. When sown after mid-September yields were proportional to plant size at initiation. The winter was mild, and in colder conditions earlier sowing may be required to enable plants to reach a critical size before initiation takes place. When sown in August plants were very large but yield was not improved. A study of the development of the pod canopy showed that the extra yield potential was not realized because heavy losses of pods and seeds occurred, particularly in the more shaded positions.When a range of winter varieties, chosen to contrast the timing of phasic development, was sown on two dates yield was proportional to the interval between sowing and initiation, particularly when late sown, presumably because late initiators were able to lay the foundation of a more substantial root and shoot system. This has implications for plant breeding programmes because the low erucic acid varieties currently being grown initiate inflorescences early. When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants, with a low yield. Winter types sown in March did initiate flowers and produce large plants, but yields were no better than spring types as flowering and ripening were irregular and late, the cold requirement for initiation being only marginally fulfilled.

EVALUATION OF FULL-FAT SPAN RAPESEED AS AN ENERGY AND PROTEIN SOURCE FOR LAYING HENS

Full-fat Span rapeseed (a low erucic acid variety), which had been steam-treated at 90 C for 30 min and then ground, was examined as a protein and energy source in rations of Single Comb White Leghorn laying hens during a laying period of 336 days. The levels of mortality and egg production were not significantly affected by the inclusion of 0, 5, 10 or 15% Span rapeseed in the ration; however, calculation of the simple regression between hen-day production and level of rapeseed used indicated a significant decrease in production with increasing levels of rapeseed in the ration. No mortality was attributed to ’haemorrhagic liver syndrome’ in the groups fed rations containing 0 and 5% rapeseed but the incidence of haemorrhagic liver syndrome was 3.1 and 4.2%, respectively, in birds fed rations containing 10 and 15% rapeseed. Egg quality, feed conversion and body weight were not affected by any of the dietary treatments. The sizes of the livers and hearts and their composition of dry matter, fat and protein were not significantly affected by dietary treatments. There was, however, a progressive and significant (P < 0.05) increase in the relative weights of the thyroids as the level of rapeseed in the ration was increased.

Effects of Span Rapeseed on the Performance, Organ Weights and Composition of the Carcass, Heart and Liver of Broiler Chicks

Experiments were conducted to study the effects of varying levels of arginine and Span rapeseed (a low erucic acid variety) on the performance, organ weights and composition of the carcass, heart and liver of broiler chicks. Chicks fed rations containing 20% ground raw rapeseed gained weight more slowly, showed increased feed requirement per unit gain and produced leaner carcasses than chicks fed a control ration containing soybean meal or a ration containing 20% ground autoclaved rapeseed. Increasing the level of autoclaved rapeseed beyond 20% in the ration tended to reduce chick performance and produce leaner carcasses. Supplementation of rations with arginine had no significant effect on rate of growth, efficiency of feed conversion or carcass composition.Rations containing raw rapeseed caused thyroid enlargement. Autoclaving the seed for 10 minutes at 120°C. reduced this effect. No appreciable differences in the sizes of the livers and hearts were observed amongst the groups fed the different rations. Inclusion of rapeseed in the ration (either raw or autoclaved) resulted in a lower percentage of fat and a higher percentage of protein in the hearts of chicks than were obtained when the control ration was fed. The dietary treatments employed apparently had no effects on the liver composition. The inclusion of rapeseed in the rations resulted in a lower percentage of carcass fat and a higher percentage of carcass protein than were obtained on the control ration. The use of raw rapeseed gave lower carcass fat levels than when autoclaved rapeseed was used.

PERFORMANCE AND HISTOLOGICAL CHANGES IN TISSUES OF PIGS FED DIETS CONTAINING HIGH OR LOW ERUCIC ACID RAPESEED OILS OR SOYBEAN OIL

Three experiments were conducted to compare high (20.6%) or low (4.0%) erucic acid rapeseed oils with soybean oil when the oils were fed at a level of 15% of the diet for pigs from 25 to 90 kg liveweight. The low erucic acid rapeseed oil originated from Brassica campestris cv. Span. A fourth diet containing no supplemental oil served as a control. In one experiment, 48 crossbred pigs were fed ad libitum in groups of three pigs replicated four times. In a second experiment, 48 pigs were individually fed at a level of 80% of the daily caloric intake of the pigs in the first experiment. In a third experiment, 16 pigs in four groups were allowed continuous free-choice access to the four diets. Serial slaughter and digestibility data were obtained. The incorporation of high or low erucic acid rapeseed oil in the diets did not reduce pig performance when such diets were fed either ad libitum or at a restricted level. When given a choice of feed, pigs selected less of the high erucic acid rapeseed oil diet. When not given a choice of feed, pigs consumed as much of a high erucic acid rapeseed oil diet as they did of the other diets. Digestibility coefficients for energy, nitrogen and lipids were not significantly different for any of the three oil-containing diets. Histological examination of the heart, liver and spleen revealed no marked differences due to feeding any of the oil-based diets.

Studies of the mode of action of erucic acid on heart metabolism.

The effects of erucic acid on the oxidative metabolism of rat-heart mitochondria have been investigated using intact animals, perfused beating heart, isolated mitochondria and mitochondrial extracts. Feeding rats with a diet containing erucic acid was found to lead to a diminished ability of the isolated heart mitochondria to oxidize various substrates, in accordance with previous reports (Houtsmuller et al., Biochim. Biophys. Acta 218 (1970) 564). This effect was almost pronounced with palmitylcarnitine as substrate, in which case the rate of oxidation was decreased by more than 50% at such a low erucic acid content in the diet as 1.4% given over 2-4 weeks. Oxidation of palmitylcarnitine was also found to be inhibited when erucylcarnitine was added to isolated heart mitochondria from control animals, in agreement with earlier observations (Christophersen and Bremer, FEBS Lett. 23 (1972) 230; Biochim. Biophys. Acta 280 (1972) 506). The inhibition was accompanied by a decrease in the rate and extent of reduction of mitochondrial flavoprotein. Experiments with perfused beating rat-heart likewise revealed an inhibition of flavoprotein reduction, as well as nicotinamide nucleotide reduction, when erucate was added to the perfusing medium of the beating heart respiring with oleate--but not with octanoate--as substrate. These data together with those earlier published in the literature indicate that erucic acid may interfere with the enzyme system involved in the mitochondrial oxidation of long-chain fatty acids, probably at the level of acyl-CoA dehydrogenase. Kinetic data supporting this conclusion, obtained with extracts of rat-heart mitochondria containing the acyl-CoA dehydrogenase and electron-transferring flavoprotein system, are presented. The possible implications of these results for the known effect of dietary erucic acid in causing an accumulation of fat in the heart are discussed.

The effects of crude and refined low erucic acid rapeseed oils in diets for broiler chickens

1. The effects of feeding diets containing 15% of low erucic acid Zephyr rapeseed oil (B. napus) and of crude, refined and hydrogenated Span rapeseed oils (B. campestris) on growth and on tissue lipids of female broilers were determined. 2. Feeding refined or hydrogenated Span oil led to smaller body weights than feeding soybean oil, while refined Zephyr oil and crude Span oil supported a growth response similar to soybean oil. 3. The treatments had significant effects on the total lipid contents of heart (P ≤ 0.05) and spleen (P ≤ 0.001) but not liver. 4. There was no indication of lipid accumulation in the tissues of the chickens fed low erucic acid rapeseed oil as compared with those of the birds fed soybean oil. 5. Only small amounts of erucic acid were incorporated into heart, liver or spleen lipids when rapeseed oil was fed.

The effects of crude and refined low erucic acid rapeseed oils in diets for laying hens

1. The effects of feeding diets containing 15% crude or refined low erucic acid Span rapeseed oils, refined regular rapeseed oil or lard to pullets on productive performance and the lipids of egg yolk were determined. 2. Productive performance was best with the low‐fat control diet, less good with the crude low erucic acid Span oil or lard‐containing diets, intermediate with the diet containing refined Span oil and worst with the diet containing regular rapeseed oil. 3. The various dietary treatments did not affect total lipid content of egg yolk but did affect the fatty acid composition of egg yolk lipids. 4. No substantial amounts of erucic acid were found in the eggs indicating that the hen is able to control the lipid concentration in egg yolk though control of the fatty acid composition of lipids is poorer.

OIL, FATTY ACID AND CHLOROPHYLL ACCUMULATION IN DEVELOPING SEEDS OF TWO "LINOLENIC ACID LINES" OF LOW ERUCIC ACID RAPESEED

Fatty acid composition and oil formation were followed in developing seeds of two "linolenic acid lines" of low erucic acid rapeseed (Brassica napus L.) containing above and below normal linolenic acid levels to determine how these different levels of linolenic acid are derived. Under controlled growth room conditions, patterns of fresh weight and dry weight accumulation showed that seeds of both lines matured over the same period of time. During this time, both lines accumulated equivalent amounts of oil. The fatty acid composition of the oils of mature seed of both lines were similar for palmitic (16:0), palmitoleic (16:1), stearic (18:0), linoleic (18:2) and eicosenoic acid (20:1) when expressed either on a percent basis or a weight basis. However, oleic (18:1) and linolenic (18:3) acid were reciprocally related on a percent basis. The seeds of the two lines accumulated different weights of oleic and linolenic acid. Since the accumulation occurred over the same length of time, the difference in oleic and linolenic acid content was caused by different rates of accumulation. Equivalent chlorophyll contents, obtained for both lines, failed to show a relationship between chlorophyll content (indicative of photosynthetic activity) and linolenic acid accumulation.

INHERITANCE OF OLEIC, LINOLEIC AND LINOLENIC ACIDS IN SEED OIL OF RAPESEED (BRASSICA NAPUS)

The fatty acid composition of rapeseed (Brassica napus L.) oil was investigated in parental, F1 and F2 plant populations of three crosses among three low erucic acid lines differing in oleic, linoleic and linolenic acid content. The F1 plant population values indicated that the oleic and linoleic acid contents were controlled by a simple additive gene system in one cross. In the other two crosses, partial dominance for high oleic and low linoleic content was observed. Dominance of low linolenic acid values was observed. The heritability estimates for oleic and linoleic acid were similar within each cross. The heritability estimates ranged from 53 to 78% for oleic, 40 to 84% for linoleic and 26 to 59% for linolenic. The estimates of minimum number of effective factors controlling oleic, and linoleic were similar within each cross. The number of effective factors ranged from 2 to 6 for oleic, 3 to 5 for linoleic, 0 to 4 for linolenic. The similarity of genetic behavior of oleic and linoleic acid content within each cross and the very high negative correlation between these components suggests that the relative ratios of oleic and linoleic acid content may be under the control of one genetic system.

VITAMIN E AND HIGH OR LOW ERUCIC ACID RAPESEED OILS IN BROILER DIETS

Regular rapeseed oil (RSO) from rapeseed containing approximately 25% erucic acid (C22:1) and low erucic acid rapeseed oils (LEAR) containing approximately 2.5% C22:1 prepared from the Oro (ORO and hydrogenated Oro oil, HORO) and Span (SPO) varieties of rapeseed were compared against soybean oil (SBO) or lard (LA) in diets for broilers. Two diets were formulated from each oil or fat, one containing no supplementary vitamin E, the other containing 30 mg/kg of supplementary vitamin E. Each ration was fed to two groups of 10 broiler-type chicks from day-old to 8 wk of age. Growth, lipid content and fatty acid composition of heart, liver and spleen tissues and plasma cholesterol levels were studied. Average body weight was highest in the chickens fed the SBO-, LA-, ORO- or HORO-containing diets, intermediate for SPO and lowest for the RSO-containing diet. Inclusion of supplementary vitamin E in the oil or fat-containing diets improved the growth rate in all cases. However, vitamin E status did not appear to be related to the deleterious effects reported with feeding high levels of rapeseed oil. No treatment effects were noted on the total lipid concentrations in heart and liver tissue. The total lipid concentration in the spleen was somewhat higher in chickens fed RSO than in those fed the other oils. RSO led to a relatively high, while LEAR oils led to minimal, tissue incorporation of C22: 1. Erucic acid concentration was highest in adipose tissue (9.2%), followed by breast muscle (6.8%), spleen (5.9%), cardiac tissue (4.8%) and liver (2.6%). Plasma cholesterol concentrations (PC) were highest in the chickens fed the RSO- and SPO-containing diets (122 mg % and 134 mg %, respectively); the other oils led to lower PC levels (approximately 100 mg %). It appears that the liver tissue can metabolize C22: 1 better than the other body tissues studied, perhaps by increased oxidation or by increased transport as cholesterol esters.

Low Erucic Acid Rapeseed Oils in Rations for Broiler Chickens: Oro and Hydrogenated Oro Oil

The effects of feeding broiler-type chickens rations containing 5% or 15% of a low erucic acid rapeseed oil prepared commercially from the Oro variety of rapeseed (ORO), a commercially hydrogenated Oro oil (HORO) and soybean oil (SBO) on body weight, apparent digestibility of total fatty acids, weights of heart, liver and spleen, total lipid and total fatty acid content of heart and liver and fatty acid composition of heart and liver lipids were studied. The experimental diets were fed ad libitum to the chickens from day old to four weeks of age.Body weight and weights of heart and liver were not influenced significantly by the dietary treatments. Spleen weight was smallest in the group fed the 15% ORO—containing diets.The apparent digestibilities of total fatty acids were similar for ORO and SBO (89.4% and 94.2% for 5% and 15% ORO; 90.9% and 94.7% for 5% and 15% SBO), however they were lower for HORO (85.7% and 90.2% for 5% and 15% HORO).Total lipid and total fatty acid contents of liver were not influenced significantly by the different dietary treatments. Feeding 5% ORO in the diet decreased the content of total fatty acids in heart as compared to feeding 5% HORO or 5% SBO in the diet. The fatty acid composition of heart and liver lipids was influenced by the fatty acid content of the diets. Only small amounts of erucic acid were found in the tissues of the birds fed diets containing ORO or HORO.The inclusion of 5% or 15% of low erucic acid rapeseed oils (ORO and HORO) in diets for broiler chickens proved nutritionally as satisfactory as the inclusion of SBO.

THE INFLUENCE OF HIGH AND LOW ERUCIC ACID RAPESEED OILS ON THE PRODUCTIVE PERFORMANCE OF LAYING HENS AND ON THE LIPID FRACTION OF EGG YOLK

The effects of including 5 or 15% of high (regular) and low (Span) erucic acid rapeseed oils or soybean oil on productive performance, total lipid and fatty acid content of egg yolk, and distribution of fatty acids in egg yolk fat were studied. Feed intake varied according to the dietary energy content. However, 15% high erucic acid rapeseed oil decreased feed intake and egg production in comparison with 15% low erucic acid rapeseed oil or soybean oil. Hens receiving rations containing soybean oil produced larger eggs in the treatment than in the pre-treatment period. Five percent regular rapeseed oil in the diet led to a small increase in egg weight, whereas inclusion of 15% regular rapeseed oil in the diet led to a decrease in egg weight. Diets containing the Span oil gave intermediate results. Although the total lipid and total fatty acid content in egg yolk remained constant, the fatty acid composition changed significantly with the experimental diets. The concentration of saturated fatty acids in eggs produced by hens fed diets containing the regular rapeseed oil or low erucic acid rapeseed oil (Span oil) decreased only to a small extent and not in proportion to the amount of these fatty acids present in the diets; but the oleic acid concentration in eggs produced by the hens fed diets containing the rapeseed oil was high. Only 0.2% of erucic acid was found in eggs when 15% regular rapeseed oil was fed to laying hens. The laying hen seems to be able to maintain the level of saturated and monounsaturated fatty acids in yolk lipids in a physiological range. The results indicate that in the laying hen, a partial degradation of erucic acid to gadoleic acid and oleic acid takes place.

GROUND RAPESEED FROM LOW ERUCIC ACID (LEAR) CULTIVARS SPAN AND ZEPHYR WITH OR WITHOUT ORGANIC ACID TREATMENT AS A DIETARY INGREDIENT FOR GROWING–FINISHING PIGS

Sixty-four crossbred weanling pigs, equalized between gilts and barrows, were fed ad libitum from 17 to 89 kg liveweight on eight dietary treatments. Diets contained 0 or 10% ground full-fat rapeseed of either Brassica campestris cv. Span or Brassica napus cv. Zephyr, both low erucic acid types. The rapeseed was treated with 0, 5 or 10% of a mixture of ⅔ acetic–⅓ propionic acid prior to grinding. One treatment was fed a diet without rapeseed or organic acids and a second fed 1% organic acids without rapeseed, a level equivalent to 10% acid added to rapeseed. The two rapeseed cultivars were similar in composition except that Span contained 1.0% C 22:1 (erucic acid) in the oil compared with 5.2% C 22:1 in Zephyr. Daily feed intake, daily gain and efficiency of feed conversion were not significantly influenced by treatment. Digestible energy (DE) per kg gain was depressed by rapeseed with or without organic acid treatment. DE and metabolizable energy coefficients were reduced by the inclusion of dietary rapeseed with or without organic acids, but the acids alone did not depress digestibility. Digestible nitrogen (DN) and N retention were not influenced significantly by diet. There was an overall trend for improved carcass quality in all treatments receiving rapeseed, or rapeseed with organic acids. There was a general increase in 18:2, 18:3 and 20:1 and decrease in 16:0, 18:0 and 16:1 (Zephyr rapeseed only) fatty acids in the carcass backfat of pigs receiving rapeseed or rapeseed plus organic acids. There was less than 0.05% C 22:1 in any of the backfats. There were no significant treatment × sex interactions. Gilts had superior carcass leanness and superior DE and DN coefficients with improved N retention compared with barrows.

COPPER AND ZINC SUPPLEMENTATION OF PIG DIETS CONTAINING SOYBEAN MEAL OR RAPESEED MEAL (BRASSICA CAMPESTRIS cv. SPAN)

Forty-eight crossbred pigs, equalized as to sex, were fed isocaloric, isonitrogenous diets with protein supplements from either soybean meal (SBM), rapeseed meal (RSM) from Brassica campestris cv. Span (low erucic acid oil) seed or a combination of SBM and RSM. Diets containing each source of protein were supplemented with 10, 135 or 210 ppm copper; some of the diets supplemented with 210 ppm copper were further supplemented with 200 ppm zinc in addition to the 50 ppm zinc added to all diets. Feed intake, efficiency of feed utilization and digestion coefficients for energy and nitrogen were not significantly (P < 0.05) affected by supplemental minerals, protein source or sex. Gain was lower (P < 0.10) for pigs fed RSM compared with SBM or SBM and RSM combined. Copper concentrations in the liver and kidney increased with increase in dietary copper levels. Two hundred and fifty ppm zinc decreased (nonsignificantly) copper stores in livers and kidneys of copper-fed pigs. Muscle and fat copper levels were not influenced by dietary minerals. Oleic acid (18:1) was higher in the depot fats of pigs receiving high level copper supplements. Dietary zinc or protein did not significantly affect fatty acid composition of adipose tissue.

An evaluation of an index method of selection for high yield in turnip rape, Brassica campestris L. ssp. oleifera Metzg

Substantial variation in yield, its primary components and several vegetative characters which influence yield was observed among a series of families drawn at random from a low erucic acid variety of turnip rape. A sib analysis of family means showed all characters to have relatively high heritabilities, although yield was, together with seed weight and specific leaf weight, in a group having the lowest values.

Effect of refining on the nutritional value of rapeseed oils for the chick and rat

AbstractExperiments were conducted to examine the effect of refining upon the energy utilisation from high erucic acid rapeseed oil, low erucic acid rapeseed oil, maize oil, soya bean oil and herring oil.When fed to chicks and rats, refined high erucic acid rapeseed oils were markedly lower in m.e. and d.e. content and gave poorer growth and feed efficiency than the corresponding crude oils. Removal of the gums present in the crude oils was partially responsible for the reduction in the available energy of the oils. Alkali refining caused a further decrease while bleaching was the major step responsible for the reduced m.e. value for the chick. Low erucic acid rapeseed oil also showed a decrease in m.e. upon refining but the decrease was relatively small as compared with high erucic acid rapeseed oils. The refining of soya bean oil, maize oil and herring oil resulted in slight increases in m.e. and thus these oils responded quite differently to rapeseed oil upon refining.