The nutritional toxicity of sweet lupin (Lupinus angustifolius) seed proteins

The effects of raw sweet lupin (Lupinus angustifolius) meal on the growth and N utilisation of rats were determined in two ad libitum and two restricted‐feeding net protein utilisation (NPU) and five N balance experiments. Sweet lupin seed grown in Western Australia, obtained as meal, either unsupplemented (LMU) or fully supplemented with required amino acids (360 g kg⁻¹) (LMFS), was tested. Rats fed lactalbumin (130 g kg⁻¹) (LACT) were used as positive controls, while rats fed a non‐protein diet (NPC) were used as negative controls. In addition, seed protein, extracted at pH 7.0 with water and insoluble after dialysis at pH 7.0 (LPADI; 124 g kg⁻¹), was also used. The diets contained the same amounts of energy and protein and were supplemented with essential amino acids, vitamins and minerals to target requirements for rats. Inclusion of LPADI in the diet of growing rats caused urinary losses of N, almost all as urea, hypoproteinaemia and increase in body water that resulted in the lowest NPU values, N balance and growth rate as compared with other diets used. These rats developed atrophy of the spleen (low dry weight) and had a comparatively smaller thymus gland than those given raw meals. Furthermore, the LPADI fraction was shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) to contain three polypeptides with molecular weights between 30 and 36 kDa which are similar to lectins obtained from Phaseolus vulgaris, Abrus precatorius and Ricinus communis. It is possible that the toxic protein component in the sweet lupin, which has negligible in vitro haemagglutination properties and is extremely toxic in vivo, exerts toxicity by interfering with protein synthesis in the liver, while the immune responses are secondary to azotaemia (high level of urea in the blood) or cytotoxicity action on lymphocytes. The unusual depletion of fat from the body, however, was due to the failure of absorbed amino acids to assimilate as proteins, creating dietary protein restriction and leading to lipolysis. It is therefore tentatively suggested that sweet lupin seed contains a lectin‐like protein that is concentrated in this fraction. Further purification and biological evaluation to establish the exact nature of this protein may be important. © 2000 Society of Chemical Industry     

Rice Protein Isolates Produced by the Two Different Methods Lower Serum Cholesterol Concentration in Rats Compared with Casein

Highly purified rice protein isolates (RPI) were prepared by an alkaline extraction–acid precipitation method (E-RPI) and by an α-amylase treatment to remove starch (T-RPI). Biological values of these RPI were significantly lower than that of casein. Serum cholesterol concentrations were compared among groups of rats fed (per kg diet) 200, 300 or 400 g E-RPI, 400 g T-RPI, 250 or 400 g casein kg⁻¹ or 400 g soya bean protein isolate (SPI). With all the diets containing 400 g protein kg⁻¹ diet, growth rates of rats were the same. At this level, E-RPI, T-RPI and SPI diets produced significantly lower serum cholesterol concentrations than the casein diet. Faecal bile acid plus neutral steroid excre-tion was significantly higher in rats fed the 400 g kg⁻¹ T-RPI or 400 g kg⁻¹ SPIdiets compared with rats fed the 400 g kg⁻¹ casein diet. On the other hand, the 400 g kg⁻¹ E-RPI diet did not increase steroid excretion. Plasma cholesterol concentrations in rats fed diets with amino acid mixtures simulating SPI and E-RPI were also significantly lower than that of rats fed the diet with an amino acid mixture simulating casein even though the faecal excretions of total bile acids were the same amongst groups. These results support the view that RPI are hypocholesterolaemic relative to casein and at least the hypocholesterolaemic effects of E-RPI would be independent of interruption of the enterohepatic circulation of endogenous steroids.     

Nutritional evaluation of transgenic high‐methionine lupins (Lupinus angustifolius L) with broiler chickens

The nutritive value of transgenic lupin seeds (Lupinus angustifolius L) with higher contents of methionine was evaluated with broiler chickens. The crude protein, methionine and cysteine contents in the conventional and transgenic lupins were 322 and 324, 2.0 and 4.5, and 3.6 and 3.7 g kg^?1 dry matter respectively. In the feeding trial, conventional and transgenic lupins with hulls were incorporated into a maize–soyabean meal diet at 250 g kg^?1 level and the diets were fed to female broiler chicks from 6 to 20 days of age. All diets were balanced to contain similar levels of apparent metabolisable energy (AME), lysine and sulphur‐containing amino acids. The levels of free methionine added to the maize–soyabean meal control, conventional lupin and transgenic lupin diets were 2.2, 2.8 and 2.2 g kg^?1 respectively. Weight gain and feed intake were not influenced by dietary treatments, but feed/gain tended to be higher (P = 0.09) in birds fed lupin diets compared with those fed the control diet. Feed/gain of birds fed the conventional lupin diet was higher (1.82 vs 1.74) than for those fed the transgenic lupin diet. These results showed that the supplemental methionine required in poultry diets containing 250 g kg^?1 lupin can be lowered by 0.6 g kg^?1 diet by the use of high‐methionine lupins. The AME values of conventional and transgenic lupins were determined to be 9.42 and 10.18 MJ kg^?1 dry matter respectively. The higher AME value in transgenic lupins may be related to the lower content of soluble non‐starch polysaccharides (45.6 vs 60.7 g kg^?1 air‐dry basis). Data on ileal amino acid digestibility indicate that the amino acids in transgenic lupins are as digestible as those in conventional lupins. © 2002 Society of Chemical Industry     

Ileal digestibility of defatted soybean,lupin and chickpea seed meals in cannulated Iberian pigs: II. Fatty acids and carbohydrates

Five castrated male Iberian pigs (100 ± 2 kg mean live body weight) fitted with T‐shaped ileal cannulas were used to determine ileal digestibility of legume seed meals. The diets were based on defatted soybean (256 g kg^?1), lupin (451 g kg^?1) or chickpea (731 g kg^?1) seed meals and contained similar amounts of digestible energy (14.2–15.1 kJ g^?1) and protein (107 g kg^?1). Only myristic acid (C14:0) ileal apparent digestibility was higher (p < 0.05) in lupin than in chickpea meal. Ileal apparent digestibility of unsaturated fatty acids (FA) (710–920 g kg^?1) was higher (p < 0.05) than that of saturated (480–710 g kg^?1) FA for both seed meals. Ileal digestibility of chickpea starch was 850 g kg^?1. Ileal digestibility of oligosaccharides (sucrose, raffinose, stachyose, verbascose and ciceritol) in lupin (820 g kg^?1) and chickpea (690 g kg^?1) was higher (p < 0.05) than that of defatted soybean (510 g kg^?1). However, total amounts of oligosaccharides digested were higher (p < 0.05) for lupin and chickpea meals (29.6 and 24.6 g kg^?1 feed respectively) than for soybean (15.2 g kg^?1 feed). Among individual non‐starch polysaccharide (NSP) sugars, ileal digestibility values for rhamnose and xylose in lupins were higher (p < 0.05) than those for soybean or chickpea. Ileal digestibility of lupin meal NSP (650 g kg^?1) was higher (p < 0.05) than those of soybean (560 g kg^?1) or chickpea (430 g kg^?1). Up to the terminal ileum, higher (p < 0.05) amounts of lupin total NSP (94.1 g kg^?1) than for soybean (24.3 g kg^?1) or chickpea (27.1 g kg^?1) were digested. Lactate, acetate and isobutyrate concentrations were higher (p < 0.05) in ileal contents of pigs fed lupin and chickpea seed meals compared with soybean‐fed animals. It is concluded that higher lactate and short chain fatty acids concentrations in ileal contents of pigs fed lupin or chickpea seed meals compared with soybean are likely to be the result of higher total amounts of lupin NSP and/or lupin and chickpea oligosaccharides digested up to the terminal ileum. This might have a protective effect on Iberian pig's intestinal physiology. Both lupin and chickpea meals are likely to constitute a valuable alternative to defatted soybean in Iberian pig feeding. Copyright © 2005 Society of Chemical Industry     

Organs relative weight and plasma amino acid concentrations in rats fed diets based on whole legume (faba bean,lupin, chickpea,defatted soybean) seed meals or their fractions

The effects on organ relative weights (g per 100 g bw) and plasma amino acid concentrations of diets based in legume (faba bean (Vicia faba), lupin (Lupinus angustifolius), chickpea (Cicer arietinum) and soybean (Glycine max)) seed meals as the only source of protein were studied with growing rats using lactalbumin or casein as controls. Also, legume seed meal extracted globulins were included in control diets replacing lactalbumin to produce legume globulin‐based diets, and legume residue fractions, containing most of the starch and/or insoluble fibre (NSP+lignin) from the seed meals, were included in control diets to reach the same amounts present in whole legume seed meal diets. All experimental diets were formulated to contain the same amounts of protein (100 g kg⁻¹) and energy (15.5 kJ g⁻¹), and were supplemented with essential amino acids. Compared with lactalbumin, higher relative weights of gastrointestinal sections were determined in rats fed legume seed meals or their corresponding residue fractions. On the contrary, spleen relative weight was lower in rats fed diets containing lupin, chickpea or soybean meals or extracted globulins, while residue fractions had no effect on it. Thymus relative weight was also lower in rats fed whole chickpea seed meal or any of the extracted legume globulins. Except for chickpea meal, animals fed legume‐ or legume protein‐based diets had lower liver relative weights than controls. Lower proportions (mg g⁻¹ tissue) of glycogen, and lower total protein and RNA, were also determined in the livers of rats fed lupin seed meal. Free plasma concentrations (mM litre ⁻¹) of glycine, histidine and arginine were higher, and threonine, leucine and lysine were lower, in rats fed diets based in all legume seed meals of their respective globulin proteins. The possible reasons and implications of these results are discussed. © 1999 Society of Chemical Industry     

Observations on the determination of protein quality by the Thomas–Mitchell method

In the Thomas–Mitchell method for the assessment of protein quality, metabolic faecal nitrogen (MFN) and endogenous urinary nitrogen (EUN) are used to adjust faecal and urinary N excretion on test diets so that true digestibility (TD) and biological value (BV) can be calculated. Using an experimental technique where the urine and faeces from young growing rats were collected every 2 days for an experimental period of 28 days, trends in the estimation of MFN and in the determination of TD and BV were examined. A diet containing 20 g egg albumen kg^?1 on an as fed basis (2.85 g N kg^?1 dry matter) has previously been found to be most applicable for the estimation of EUN. This diet was also found to be appropriate for the estimation of MFN. To examine the effect of a change from an ad libitum intake of a stock diet (containing 150 g protein kg^?1) to the restricted intake of a test diet (containing 80–100 g protein kg^?1) on the determination of TD and BV, three protein sources (egg albumen, casein+1% L -methionine and soya bean meal) were fed at two levels of intake: 9 and 15 g day^?1. The time taken for the faecal N excretion to stablilise was very similar with all diets at both levels of intake. The TD of all three protein sources at both levels of intake increased gradually with increasing lengths of preliminary period. However, this increase was not great, and had little effect on the determination of the BV. Stabilisation of urinary N excretion with the three diets depended on the quality of the protein and the amount fed. This led to variation in BV with lengthening preliminary periods, especially at the lower level of intake. Urinary N excretion, and consequently BV, stabilised most rapidly with the highest quality protein (egg albumen) at the highest level of intake. However, stabilisation of BV with the lowest quality protein (soya bean meal) did not occur until after a preliminary period of 12 days, even at 15 g day^?1. This preliminary period is considerably longer than that usually employed, and thus it appears that for many proteins the BV may have been assessed during a period before N retention has fully stabilised.     

Exocrine Pancreatic Secretions in Young Pigs Fed Diets Containing Faba Beans (Vicia faba) and Peas (Pisum sativum): Nitrogen,Protein and Enzyme Secretions

Two experiments were carried out to investigate the effect of feeding diets containing faba beans and peas on pancreatic secretions in young pigs fitted with a pancreatic pouch re-entrant cannula. In Experiment 1, eight barrows, with an average initial weight of 8·5 kg, were fed one of two maize starch-based diets formulated to contain 200 g crude protein (CP) kg⁻¹ according to a completely randomised design. In one of the diets, soya bean meal was the sole protein source; in the other diet, soya bean meal and faba beans (cv Fibro; dark-flowering) each supplied 50% of the dietary CP. In Experiment 2, five barrows, with an average initial weight of 18·1 kg, were fed one of two diets according to a two-period change-over design. The diets were formulated to contain 150 g CP kg⁻¹ with peas (cv Ascona or cv Radley) as the sole protein source. In both experiments, the experimental periods consisted of 8 days: 6 days adaptation followed by a 2 day collection of pancreatic juice. The soya bean meal diet and the faba bean diet contained 0.04 and 0.21% tannins (catechin equivalents), respectively. The trypsin inhibitor activities of the Ascona and Radley pea diets were 0·76 and 3·24 mg of trypsin inhibited per gram, respectively. In both experiments, diet did not affect ( P> 0·05) the pancreatic secretions of nitrogen, protein, amylase, lipase and chymotrypsin. In Experiment 1, specific trypsin activity was higher ( P< 0·05) in pancreatic juice from pigs fed the diet containing soya bean meal and faba beans (53700 units litre⁻¹) than for those fed the soya bean meal diet (41200 units litre⁻¹). However, there was no effect ( P> 0·05) when trypsin activity was expressed as total activity (units 24 h⁻¹). It is concluded that the inclu-sion of faba beans and peas in diets for young pigs has only minor effects on exocrine pancreatic secretions.     

Oven drying improves the nutritional value of Calliandra calothyrsus and Gliricidia sepium as supplements for sheep given low-quality straw

Leaves from the tree legumes Gliricidia (Gliricidia sepium) and Calliandra (Calliandra calothyrsus) were fed as supplements (200 g dry matter) to sheep (n=3) given a basal diet of barley straw ad libitum. Tree leaves were fed either freshly harvested (F=fresh) or after drying at 60°C in a forced draught oven (D=dried). Voluntary intakes, digestibility and aspects of nitrogen (N) and phenolic compound metabolism were measured in all sheep. Drying decreased the condensed tannin (CT) content of Calliandra (F 117, D 82 g CT kg⁻¹ DM). Total phenolics (TP) were significantly decreased when Gliricidia was dried (F 39, D 21 g TP kg⁻¹ DM), and CT content was reduced from 20 g CT kg⁻¹ DM to zero. Sheep given Gliricidia had higher rumen ammonia concentrations (73–85 mg N litre⁻¹) than did sheep given Calliandra (37–40 mg N litre⁻¹). For both species, drying significantly increased the voluntary consumption of straw, increased DM digestibility, decreased faecal N excretion and increased N balance. For calliandra, drying decreased the apparent degradability of N in the rumen (DNR) from 0·40 to 0·28 g N g⁻¹ N ingested, and increased the apparent digestibility of N (ADN) in the post-ruminal tract from 0·20 to 0·52 g N absorbed g⁻¹ N flowing into the small intestines. For Gliricidia, DNR decreased from 0·64 to 0·51 and ADN increased from 0·41 to 0·56. There were no significant effects of drying on rates of microbial N synthesis. The above changes were discussed in relation to changes in tannin content and it was concluded that drying facilitates the formation of protein–tannin complexes which protect proteins from degradation in the rumen. These proteins are subsequently released in the small intestines, thereby promoting an increased efficiency of dietary N utilisation. ©1997 SCI     

Chemical Composition of Pea Fibre Isolates and their Effect on the Endogenous Amino Acid Flow at the Ileum of the Pig

Pea starch, hulls and cotyledon inner fibres, isolated from pea seeds, were incorporated in N-free diets, on a NDF-content basis, in order to study their effect on the ileal endogenous amino acid (AA) excretion in the growing pig. Maize starch and wood cellulose were selected as references. The inner fibre-containing diet was also supplemented with enzymatically hydrolysed casein (EHC) in order to test the peptide alimentation method on a diet containing a fibre source with a high water-holding capacity (WHC=10·9 g water g⁻¹ DM). The fibres were also analysed by different methods (crude fibre, NDF, ADF, enzymatic–gravimetric method, Englyst method). The fibre content of the inner fibre fraction varied widely from one method to another and ranged from 109 g crude fibre to 480 g AOAC fibre kg⁻¹ DM. Compared to the ‘maize starch+wood cellulose’ diet (11·0 g AA excreted kg⁻¹ DM intake), pea starch had no effect on ileal AA losses (9·6 g), whereas pea hulls slightly increased them (14·2 g). The AA excretion dramatically increased with the incorporation of inner fibres (28·0 g), because of their very high WHC. The addition of EHC increased the output (48·0 g) further, at a level that can hardly be explained only by an increase of the endogenous secretions. The results suggest that the NDF content of grain legume products is not indicative of their effect on the ileal endogenous AA losses in pigs and that the physiological effects of fibres along the gastrointestinal tract are due to both their chemical and physical properties.     

Chemical composition,digestibility and protein quality of 12 sunflower (Helianthus annuus L) cultivars

Twelve sunflower (Helianthus annuus L) cultivars grown in Spain were analysed and tested in experiments with rats. The dehulled seeds contained an average of 32.2 MJ kg⁻¹ dry matter (DM) gross energy, 653 g kg⁻¹ DM fat, 60 g kg⁻¹ DM total non-starch polysaccharides (NSP) and 6 g kg⁻¹ DM Klason lignin. The sunflower seed hulls contained 20.2 MJ kg⁻¹ DM gross energy, 53 g kg⁻¹ DM fat, 562 g kg⁻¹ DM total NSPs and 239 g kg⁻¹ DM Klason lignin. The sunflower samples were dehulled and partially defatted (to ∼17% fat) and included in diets for rats. The dehulled, partially defatted samples contained on average 74.6 g nitrogen kg⁻¹ DM and 1.409 mg g⁻¹ phenolic compounds (chlorogenic acid + caffeic acid + derivative 1 + derivative 2) varying from 0.677 to 2.847 mg g⁻¹. Groups of five growing rats were fed diets (9.38% crude protein) containing one of the sunflower cultivars as the only source of protein. Apparent ileal and faecal digestibilities were determined by using an indigestible marker (Cr₂O₃) and faecal digestibility based on total faecal collections. Apparent ileal, caecal and faecal digestibilities of organic matter were 81.2–91.5% (P = 0.05), 95.8–97.1% (P = 0.005) and 94.7–95.3% (P = 0.94) respectively. The apparent faecal digestibilities of DM, energy and protein (N × 6.25) were 93.2–93.8%, 93.5–94.3% and 81.6–84.3% respectively with no differences among cultivars. Biological value (BV) ranged between 63.8 and 73.2% (P = 0.0001) and net protein utilisation (NPU) between 59.9 and 69.5% (P = 0.0001). BV and NPU were positively correlated with lysine and threonine contents, but no correlation with the analysed phenolic compounds was detected. © 1999 Society of Chemical Industry     

Ileal digestibility of defatted soybean,lupin and chickpea seed meals in cannulated Iberian pigs: I. Proteins

Five castrated male Iberian pigs (100 ± 2 kg body weight) fitted with T‐shaped cannulas at the terminal ileum were used to determine ileal digestibility of legume seed meals. The diets were based on defatted soybean, lupin or chickpea seed meals and contained similar levels of digestible energy (14.2–15.1 kJ g^?1) and protein (107 g kg^?1). Protein‐free and a hydrolysed casein diets were used to study endogenous ileal amino acid flows. Chromium oxide (10 g kg^?1 diet) was added to the diets as an indigestible marker. Ileal flows in pigs fed the hydrolysed casein diet were different (p < 0.05) in amino acid contents and composition from those on the protein‐free diet. Ileal sialic acid flows in pigs fed lupin‐ or chickpea‐based diets were higher (p < 0.05) than those of animals fed soybean or casein diets. Among essential amino acids, only the apparent ileal digestibilities of phenylalanine and valine in lupin meal were lower (p < 0.05) than those in soybean. Apparent ileal digestibilities of lupin aspartate and proline, together with chickpea aspartate, were also lower (p < 0.05) than those of soybean. True ileal digestibility of nitrogen in pigs fed lupin or chickpea meals, calculated according to values from animals fed the protein‐free diet, was lower (p < 0.05) than that for soybean or casein. Among individual essential amino acids, only the true ileal digestibility of phenylalanine in lupin was lower (p < 0.05) than that in soybean. True ileal digestibility of nitrogen calculated according to values obtained with pigs fed a hydrolysed casein diet was not different among soybean, lupin or chickpea meals. Among essential amino acids, only the true ileal digestibilities of isoleucine and lysine in chickpea were lower (p < 0.05) than those of soybean. It is concluded that true ileal nitrogen and amino acid digestibilities of lupin and chickpea meals are comparable to those of defatted soybean in Iberian pigs. The results with protein‐free diets tended to underestimate endogenous protein secretion in pigs fed on diets containing protein. Copyright © 2005 Society of Chemical Industry     

The Nutritive Value of Mango Seed Kernels for Starting Chicks

Raw mango ( Mangifera indica L) seed kernels were found to contain tannins (56·5 g kg⁻¹ DM), cyanogenic glucosides (64 mg kg⁻¹ DM), oxalates (42 mg kg⁻¹ DM) and trypsin inhibitory activity (20 TIU g⁻¹ DM). The contents of these anti-nutritive factors were lowered by both soaking and boiling treatments, but boiling was more effective. The in vitro protein digestibility (26·3%) and apparent metabolisable energy (7·88 MJ kg⁻¹ DM) values of raw kernels were low, and these parameters were improved by soaking and boiling. The observed improvements paralleled reductions in tannin contents, indicating that tannins are largely responsible for the poor nutritive value of raw kernels. In experiment 1, diets containing 0, 50, 100, 150 and 200 g kg⁻¹ raw mango seed kernels that replaced maize were fed to 7-day-old White Leghorn cockerels for 14 days. Inclusion of more than 50 g kg⁻¹ raw kernels lowered ( P< 0·05) the weight gains, feed intake and feed efficiency of chicks. High level inclusion of raw kernels had toxic effects, as evidenced by increased mortality. In experiment 2, soaking and boiling treatments improved ( P< 0·05) feed intake of chicks fed on diets containing 100 g kg⁻¹ kernels and reduced mortality. Feed/gain was unaffected by processing. Soaking had no effect, whereas boiling of kernels improved the weight gains. However, weight gains of chicks receiving diets containing 100 g kg⁻¹ boiled kernels were numerically, though non-significantly, lower than those of the maize-control group. It is concluded that raw mango seed kernels are unsuitable as a feed ingredient in chick diets and, that soaking and boiling do not completely overcome the anti-nutritive effects of raw kernels.     

The choline content of feed ingredients and mixed feeds determined by an enzymatic assay

A recently developed procedure for the determination of choline in ingredients and feeds was utilised to establish the levels and the variability of choline in a series of ingredients and to compare the analysed and calculated choline values of mixed feeds. The concentrations of choline in samples of maize (7), canola meal (3), wheat middlings (1) and dehydrated bakery product (1) were, respectively, 1·55±0·18, 7·59±0·08, 2·35 and 2·39 g kg⁻¹, all higher than ingredient composition table values. Choline contents lower than table values were found in samples of poultry by-products (7) and meat and bone meal (6): 2·18±0·87 and 1·08±0·29 g kg⁻¹, respectively. The average choline concentration found in samples of dehulled soybean meal (7) was 2·73±0·18 g kg⁻¹, similar to table values. The choline in samples of poultry fat (2) averaged 0·48±0·02 g kg⁻¹. Significant correlations between the concentrations of choline and of some components of the proximate analysis were found. The analysed choline concentrations in mixed feeds were only 1·4% lower than the calculated levels based on the ingredient analyses. The procedure was adequate for choline determination in ingredients or mixed feeds. The high variability in the choline content of some ingredients may require analysis for proper feed formulation. © 1998 Society of Chemical Industry.     

Response of nutrient digestibilities to feeding diets with low and high levels of soybean trypsin inhibitors in growing pigs

Studies were carried out to determine the effect of dietary soybean trypsin inhibitor (SBTI) content on nutrient and energy digestibilities in growing pigs. Six barrows, average initial body weight (BW) 47·8±4·0 kg, were fitted with a simple T-cannula at the distal ileum and fed two diets according to a crossover design. Two maize starch-based diets were formulated to contain 200 g crude protein (CP) kg⁻¹ from either Nutrisoy (a food-grade defatted soy flour) or autoclaved Nutrisoy. The contents of SBTI in the Nutrisoy and autoclaved Nutrisoy diets were 13·4 and 3·0 g kg⁻¹, respectively. The experiment consisted of two periods of 12 days each. The average BW at the start of the first and second experimental periods were 53·3±3·7 and 61·0±5·1 kg, respectively. The average BW at the conclusion of the experiment was 71·8±7·6 kg. The ileal digestibilities of dry matter (DM), organic (OM), energy, CP and all amino acids measured were higher (P<0·01) in pigs fed the autoclaved Nutrisoy diet. The energy digestibility increased from 66·0 to 77·9%, and the CP digestibility increased from 37·4 to 77·1%. The increases in ileal digestibilities of the indispensable amino acids ranged from 27·0 (methionine) to 49·2 (leucine) percentage units. The increases in ileal digestibilities of the dispensable amino acids ranged from 30·2 (aspartic acid) to 50·8 (tyrosine) percentage units. The faecal digestibilities of all criteria measured were also higher (P<0·01) in pigs fed the autoclaved Nutrisoy diet. Furthermore, there was a greater (P<0·01) net disappearance (g kg⁻¹ DM intake) of DM, OM, CP, energy and all amino acids in the large intestine of pigs fed the Nutrisoy diet. In conclusion, feeding diets containing high levels of SBTI decreased both ileal and faecal digestibilities of all criteria measured. The formation of SBTI-enzyme complexes is likely to be responsible for the reduction in protein digestion and amino acid absorption. © 1998 SCI.     

Rapeseed Meals,Methimazole, Thiocyanate and Iodine Affect Growth and Thyroid. Investigations into Glucosinolate Tolerance in the Pig

In two factorial experiments with a total of 81 growing pigs, the effects of antithyroid compounds and rapeseed meal (RSM) diets differing in glucosino-late content were tested without or with supplementary iodine. In Experiment 1, a 4×3 factorial arrangement was used to investigate the effects of antithyroid compound inclusion and supplementary iodine. Pigs received a grain–soya bean meal diet (control) or this diet with 250 mg kg^-1 methimazole (MMI), 1000 mg kg^-1 thiocyanate (SCN^- as KSCN) or 80 g kg^-1 high glucosinolate RSM (9·5 mmol glucosinolates kg^-1), each diet supplemented without or with iodine; 0, 125 μg kg^-1 (requirement) or 500 μg kg^-1. In Experiment 2, a 5×3 factorial arrangement was used to study the effects of dietary glucosinolate content and iodine supplementation. Pigs received a grain–soya bean meal diet or four diets with 160 g kg^-1 RSM differing in glucosinolate content (0·6, 2·4, 6 or 19 mmol kg^-1 diet), each diet supplemented with iodine: 62·5 μg kg^-1, 125 μg kg^-1 (requirement) or 250 μg kg^-1. Irrespective of the iodine dosage, MMI suppressed production of thyroxine and resulted in goitre, myxoedema and cretinism. SCN^- induced clinical hypothyroidism when there was no supple-mental iodine. Despite high iodine supplementation, glucosinolate load (19 mmol kg^-1 diet) decreased growth, feed intake, iodine store of the thyroid and serum concentration of thyroid hormone and resulted in goitre formation. In the case of diets with ⩽6 mmol glucosinolates kg^-1, iodine prevented antithyroid effects. However, more iodine was required by these pigs than by control animals to a high T₄ serum concentration. The lowest glucosinolate level tested (0·6 mmol kg^-1 diet) yielded the same thyroid hormone status and thyroid weight as the control, however, the iodine content of thyroid gland was decreased. In conclusion, iodine administration prevents the effects of a low glucosinolate intake only, by overcoming the depressed thyroxine released of the thyroid, resulting in regression of goitre. © 1997 SCI.     

Particle Size of Whole Meal Rye Bread does not Affect the Digestibility of Macro-Nutrients and Non-Starch Polysaccharides and the Energy Value of Dietary Fibre in Humans

The effect of particle size of whole meal rye bread on the apparent digestibility of macro-nutrients, non-starch polysaccharides (NSP) and energy, the energy value of rye NSP and on faecal weight was studied in balance experiments in seven young women. The whole meal breads were prepared from one single batch of rye milled to two different particle sizes (coarse bread: 50% of particles >2 mm, 90% >1 mm; fine bread: 86% of particles <0·5 mm, 58% <0·2 mm). Two diets containing either coarse (350 g day⁻¹) or fine (377 g day⁻¹) whole meal bread and a low fibre control diet were consumed for 3 weeks each in a 3×3 cross-over design. Relative to the low fibre control diet, digestibility of protein, NSP and energy was significantly lower for the diets containing the whole meal breads. Digestibility of fat was the same for all diets. Partial digestible energy value for each g of NSP from coarse and fine whole meal rye bread was calculated to be −3±7 and 1±5 kJ, respectively. There were no differences between coarse and fine whole meal rye bread in the effects on the parameters measured with the exception on faecal wet weight, which was higher for the coarse bread diet.     

Exocrine Pancreatic Secretions in Young Pigs Fed Diets Containing Faba Beans (Vicia faba) and Peas (Pisum sativum): Concentrations and Flows of Total,Protein-Bound and Free Amino Acids

Two experiments were carried out to investigate the effects of feeding diets containing faba beans and peas on the concentration, flow and composition of total, protein-bound and free amino acids (AA) in pancreatic juice collected from young pigs fitted with a pancreatic pouch re-entrant cannula. In Experiment 1, eight barrows, with an average initial weight of 8·5 kg, were fed one of two semi-purified diets formulated to contain 200 g kg⁻¹ crude protein (CP) according to a completely randomised design. In one of the diets, soya bean meal was the sole protein source; in the other diet, soya bean meal and faba beans (cv Fibro; dark-flowering) each supplied 50% of the dietary CP. In Experiment 2, five barrows, with an average initial weight of 18·1 kg, were fed one of two diets formulated to contain 150 g kg⁻¹ CP with peas (cv Ascona or cv Radley) as the sole protein source. There was no effect (P>0·05) of the diet, 8 h sampling period or experimental period on the concentration (mM), composition (% and g 16 g N⁻¹) and flow (mmol 24 h⁻¹) of total, protein-bound and free AA or on the percentage of protein-bound AA in pancreatic juice. The concentrations of total, protein-bound and free AA were higher in pancreatic juice collected from younger pigs in Experiment 1 than in pancreatic juice collected from older pigs in Experiment 2. However, the daily flows of total, protein-bound and free AA in pancreatic juice were similar in both experiments. The percentages of protein-bound AA in pancreatic juice were similar in both experiments. In conclusion, the concentrations, compositions and flows of total, protein-bound and free AA in pancreatic juice were not affected by diet, 8 h sampling period or experimental period.     

Determination of Chlorogenic Acids with Lactones in Roasted Coffee

An HPLC method has been developed which allowed the determination of mono- and dicaffeoylquinic acids (CQA and di-CQA), corresponding lactones (CQL) and feruloylquinic acids (FQA) in roasted coffee within one chromatographic run. The elution order was verified by isolation of the individual compounds by preparative HPLC, chromatography of the fractions on the analytical HPLC system, NMR spectroscopy and thermospray LC-MS. At least 15 additional minor compounds had the spectra of hydroxycinnamic acids, some of them only occurring in roasted coffee. Caffeoyltryptophan, which has been identified some time ago by another working group could also be separated with this system. The average contents in commercial roasted coffee samples (n=12) were: 3-CQA, 5·0 g kg⁻¹; 4-CQA, 6·2 g kg⁻¹; 5-CQA, 11·4 g kg⁻¹; 4-FQA, 0·7 g kg⁻¹; 5-FQA, 1·4 g kg⁻¹; 3-CQL, 2·1 g kg⁻¹; 4-CQL, 1·0 g kg⁻¹; 3,4-di-CQA, 0·7 g kg⁻¹; 3,5-di-CQA, 0·4 g kg⁻¹ and 4,5-di-CQA, 0·8 g kg⁻¹ dry matter. There were only small differences between the different brands. Two series of samples with different degrees of roast produced from the same green coffee have also been analysed. One series was steam treated before roasting (a process which is commercially used to improve digestibility). Only in the initial stages of roasting (light roast) could a difference in the contents of the acids between both series be observed. Keeping coffee brews at an elevated temperature (4 h at 80°C) reduced the amounts of CQL to 60% of the initial value. The contents of 3-CQA and 4-CQA increased, whilst that of 5-CQA decreased. The overall contents of CQA decreased.     

In vitro protein digestibility and mineral availability of green beans (Phaseolus vulgarisL) as influenced by variety and pod size

Three varieties of green beans (Cleo, Strike and Sentry) were harvested and sorted into four fractions according to pod size (diameter <7 mm; 7–8·5 mm; 8·6–10 mm and >10 mm). Ash content and dietary fibre increased significantly as pod size increased mainly in Cleo and Strike beans. Strike showed the highest fibre content (378·0 g kg⁻¹) but the lowest carbohydrate (364·6 g kg⁻¹) and ash (68·4 g kg⁻¹) values. Mean values for Fe and Mg content were higher in Cleo beans (70·9 and 27·1 mg kg⁻¹, respectively), Zn, Cu and Mg were higher in Strike beans (48·7 mg kg⁻¹, 22·4 mg kg⁻¹ and 3·15 g kg⁻¹, respectively) while Na and Ca values were maximum in Sentry (459·1 mg kg⁻¹ and 7·11 g kg⁻¹, respectively). Trypsin inhibitor was negatively related to in vitro protein digestibility but no relationship was found between this last parameter and phytic acid content. This antinutrient, together with dietary fibre, and a negative influence on in vitro mineral dialysability of green beans. © 1998 SCI     

The effect of village processing techniques on the content of aflatoxins in corn and peanuts in Zambia

The effect of village processing techniques on the aflatoxin content of corn and peanut products was investigated. In 30 trials, corn kernels were dehulled (bran removal), soaked for 24 h, washed and dried before grinding into flour and boiling in water to a thick consistency (Nshima). Shelled peanuts were either dry-roasted as whole kernels or ground into peanut meal and cooked. Dehulling, following by 24-h soaking (steeping) and subsequent washing significantly (P<0·05) reduced the aflatoxin B₁ content of corn flour from 900 to 150 μg kg⁻¹, and similarly that of aflatoxin G₁ from 929 to 114 μg kg⁻¹. Preparation of Nshima did not result into a substantial reduction in aflatoxin content, neither did extension of the cooking duration of 2 h afford any further decontamination. Whereas boiling peanut meal yielded a moderate reduction in the content of aflatoxins B₁ and G₁, roasting whole peanut kernels greatly reduced (P<0·001) the concentrations of the toxins from that in raw kernels (AFB₁= 8600 μg kg⁻¹ and AFG₁=6200 μg kg⁻¹) to 1300 and 1200 μg kg⁻¹, respectively. These results indicate that specific processing techniques carried out in Zambian villages are effective in reducing aflatoxin carry-over into edible fractions, while others are not. © 1998 SCI.