Comparative effects of wheat bran and barley husk on nutrient utilization in rats. 1. Protein and energy

1. The present work with growing rats was undertaken to compare the effect of wheat bran and barley husk on nutrient bioavailability. The experiment involved a total of nine dietary treatments consisting of a control group, without wheat bran or barley husk, and two series of four groups with increasing amounts of fibre from 50 to 117 g/kg dry matter (DM) from the two fibre sources. Dietary nitrogen concentration was kept constant at 15 gN/kg DM by adjusting the diets with an N-free mixture. Protein sources were casein, fortified with methionine and white wheat flour. True protein digestibility (TD), biological value (BV), net protein utilization (NPU) and digestible energy (DE) were estimated. 2. TD decreased when total dietary fibre (TDF) increased, the effect being greater in the case of wheat bran. The difference in response can be explained by the larger N contribution from bran than from barley husk. N from barley husk was actually digested less than N from wheat bran. 3. Changes in TD due to fibre were small, both for wheat and barley husk. It was concluded that decreased TD with fibre at moderate levels was due to poor digestibility of the N associated with the fibre source rather than decreased digestibility of N from other dietary components. 4. BV was only marginally affected by the fibre levels, indicating that the relatively high lysine content in both wheat bran and barley husk had a low availability. 5. Wheat bran and barley husk showed almost the same negative effect on DE and DM digestibility (DMD). DMD correlated significantly with DE, demonstrating that DMD is a simple and convenient means of monitoring DE.     

The effect of protein quality and fibre level in the diet and microbial activity in the digestive tract on protein utilization and energy digestibility in rats

Two nitrogen-balance experiments were performed with growing rats to test the effect of dietary fibre level, protein quality and antibiotic inclusion on microbial activity, N excretion patterns and energy digestibility. Each experiments involved eight dietary treatments in a 2 X 2 X 2 factorial design, with five rats per treatment. The eight treatments resulted from a combination of two protein treatments, two fibre treatments and two antibiotic treatments. In Expt 1 the protein was provided as barley, or barley plus 2 g L-lysine hydrochloride/kg dry matter (DM) (at 15 g N/kg DM) and in Expt 2 as soya-bean meal or soya-bean meal plus 2 g DL-methionine/kg DM (at 15 g N/kg DM). In both experiments the basal diet was provided with or without additional fibre as 100 g barley husk/kg DM and with or without antibiotic as 7 g Nebacitin/kg DM. With both barley and soya-bean meal, true protein digestibility (TD) was improved with the addition of amino acids. Only with the soya-bean meal diets was TD increased with Nebacitin treatment, with the effect of Nebacitin and methionine being additive. Barley husk slightly reduced the TD of soya-bean meal. The effect of treatments on biological value (BV) was considerable. Lysine increased BV of the barley diet from 0.741 to 0.815 whereas Nebacitin reduced BV from 0.799 to 0.757. Methionine increased the BV of soya-bean meal from 0.754 to 0.911 while BV was reduced by Nebacitin from 0.843 to 0.821 and by barley husk from 0.845 to 0.820.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of provision of the first-limiting amino acid, gastrointestinal microbial activity and the level of nitrogen intake on protein utilization and energy digestibility in rats

1. The present work with growing rats was undertaken to study the effect of protein quality, gastrointestinal microbial activity and the level of nitrogen intake on protein utilization and energy digestibility. The experiment involved a total of thirty-six dietary treatments in a 9 x 4 factorial design, with five rats per treatment. The thirty-six diets resulted from nine protein sources. Each diet was composed of a basal N-free mixture plus minerals and vitamins, with N sources added at the expense of the N-free mixture to provide 15.0 gN/kg dry matter (DM) in the first three protein-addition treatments and 30.0 gN/kg DM in the fourth protein-addition treatment. The nine protein sources were soya-bean meal, casein, wheat gluten, skim-milk powder, meat-and-bone meal, wheat bran, barley, wheat and cooked brown beans (Phaseolus vulgaris). The four formulations for each protein source incorporated the protein unsupplemented at 15.0 gN/kg DM, unsupplemented at 30.0 gN/kg DM, or supplemented at 15.0 gN/kg DM with the estimated first-limiting amino acid or the antibiotic Nebacitin. 2. With all protein sources, the inclusion of the first-limiting amino acid had no effect on either protein or energy digestibility. 3. The microbial activity in the digestive tract affected protein utilization and energy digestibility to a different degree depending primarily on the level and type of dietary fibre. True protein digestibility (TD) of skim-milk powder and brown beans, both rich in easily-fermentable energy, increased from 0.959 to 1.000 and from 0.680 to 0.777 respectively by the addition of Nebacitin. TD of the other protein sources was only marginally affected by the antibiotic treatment. Only with brown beans was the biological value (BV) markedly affected by Nebacitin with an increase from 0.482 to 0.557 by the treatment. Energy digestibility was significantly lower in rats given antibiotic with soya-bean meal, wheat bran, barley, wheat and brown beans. 4. The effect of level of N intake on protein utilization was dependent on both protein quality and the fibre concentration of the diet. Protein sources with high BV were more affected than proteins of lower BV. It was concluded that TD is not always independent of dietary protein concentration.     

Nutritional response of growing rats to faba beans (Vicia faba L., minor) and faba bean fractions.

The effects of raw faba bean (Vicia faba L., minor) meal (VFM) and its fractions on the growth and nitrogen utilization of rats have been determined in two experiments. Two commercial varieties of VFM were tested, local VFM (409-439 g/kg diet) and Troy VFM (439 g/kg diet). The bean fractions tested were V. faba lectin-depleted protein (VFDP), V. faba lectin (VFL) and V. faba cotyledon residue (VFCR). All diets were supplemented with amino acids to target requirements. Body-weight, body N and lipid contents of rats fed on VFM were reduced significantly in comparison with control rats fed on lactalbumin. This was due, in part, to the lower digestibility of the protein, lipid and dry matter (DM) of VFM diets. As a result, net protein utilization (NPU) and biological value (BV) of faba bean proteins were less than expected. Urine and urea-N outputs of the VFM-fed rats were also elevated in both experiments. Increasing the energy content of local VFM diets led to significantly higher dry body-weight, body N and lipid contents, with the result that the NPU and BV values of the protein also increased. However, the NPU values for VFM-fed rats were still significantly lower than those for the controls in both experiments. In contrast, true N, lipid and DM digestibilities in rats given local VFM were not significantly affected by the difference in the energy content of the diets. The replacement of two-thirds of the lactalbumin in the diet with VFDP (65 g/kg) reduced dry body-weight, N and lipid contents, NPU and BV compared with the control rats, even though N, lipid and DM digestibilities were not significantly different. The nutritional performance of rats fed on lactalbumin-based diets containing 7 g VFL/kg was similar to that of the controls. Similarly, the inclusion of the cotyledon residue (237 g VFCR/kg diet) had no appreciable effect on any of the variables studied. As VFL and VFCR had no antinutritional effects in these rats, it appears that the low nutritional value of VFM for rats (NPU 0.66) results not only from the low digestibility of the bean proteins, but also from disturbances in N metabolism.     

The effect of methods of sterilization on the nutritive value of protein in a commercial rat diet.

1. The effect on protein quality of treating a commercial rat diet by autoclaving at various temperatures for different periods of time, or by irradiation with 2-5 or 10 Mrd, was studied. True digestibility (TD) and biological value (BV) were measured and the available and total amino acids in the diets were estimated using microbiological and chemical methods. 2. Autoclaving at 121 degrees for 60 min reduced BV, TD and net protein utilization (NPU) more than autoclaving at 134 degrees for 3 min. Availability of amino acids was reduced by both treatments but to a greater extent by autoclaving at 121 degrees for 60 min. Total amino acids were essentially unaffected. Irradiation had no effect on BV, TD, NPU or total amino acids, and the availability of amino acids was also unaffected, with the exception of lysine which was slightly reduced. 3. When the diet was autoclaved at 115 or 121 degrees for 15, 30 or 60 min, or at 134 degrees for 3 min the availability of the amino acids was reduced with increasing time and temperature of treatment. Treatment at 134 degrees for 3 min had an effect on available amino acids similar to treatment at 121 degrees for 15 or 30 min. 4. Ethylene oxide fumigation of the diet caused reduced availability of histidine, methionine and tryptophan but had negligble effect on arginine, leucine and lysine. 5. It is concluded that from a practical point of view irradiation causes least damage to proteins in rodent diets. If such diets are to be autoclaved they should be supplemented with complete protein to counteract amino acid destruction.     

The effect of dietary protein content and feeding level on the rate of protein deposition and energy utilization in growing Iberian pigs from 15 to 50 kg body weight

The effects of dietary protein content and feeding level on the utilization of metabolizable energy (ME) and on the rates of gain, protein and fat deposition have been studied in seventy-two Iberian pigs growing from 15 to 50 kg body weight (BW) by means of comparative slaughter experiments. The animals were fed on six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein ( CP)/kg DM and 14.64, 14.14, 14.37, 14.80, 15.36 and 15.53 MJ ME/kg DM respectively. Each diet was offered at three levels of feeding: 0.60, 0.80 and 0.95xad libitum intake. Protein deposition (PD) increased significantly (P<0.01) with each decrease in dietary CP content and reached a maximum value (74.0 g) when the diet providing 129 g CP/kg DM (6.86 g digestible ideal protein/MJ ME) was offered at the highest feeding level. This feeding regimen resulted in average values for live-weight gain and retained energy (RE) of 559 g/d and 10.9 MJ/d respectively. RE increased significantly (P<0.001) from 480 to 626 kJ/kg BW0.75 with each decrease in dietary CP content from 192 to 129 g/kg DM. Raising the level of feed intake led to significant linear increases in PD and RE irrespective of the diet fed (P<0.001). When diets approaching an adequate supply of CP were given, the net efficiency of use of ME for growth (kw) and the maintenance energy requirements were 58.2 % and 422 kJ/kg BW0.75 per d respectively.     

Nutritional evaluation of protein and starch of mature Canavalia gladiata seeds

Evaluation of true digestibility (TD), biological value (BV) and net protein utilisation (NPU) of diets made with raw and processed seed flour from mature Canavalia gladiata seeds were carried out with male Sprague-Dawley rats. The weight gain of the rats fed with diets containing raw whole seed and raw cotyledon alone were significantly lower (P = 0.05) than that of the group fed with the reference diet. Processing the cotyledons (dry-autoclaved or roasted) significantly (P < or = 0.05) increased the weight gain of the rats when compared to the weight gain of rats fed diets prepared with raw seed flour. NPU of raw (whole seed 13.8; cotyledon 27.6) was significantly lower (P < or = 0.05) than the reference diet (79.5). The NPU of processed samples was also significantly lower (P < or = 0.05) when (dry-autoclaved 25.1; roasted 25.1) compared to the reference diet fed group (79.5). The BV of the processed samples (dry-autoclaved 31.1; roasted 37.7) was significantly lower (P < or = 0.05) than that of raw (53.6) cotyledon. In contrast TD increased (P < or = 0.05) with processing (dry-autoclaved 80.9; roasted 65.9) when compared to raw cotyledon (51.4). In vitro protein digestibility for the raw whole seed and cotyledon was 71.7 and 70.1% respectively. In vitro starch digestibility of raw and processed cotyledon flour samples indicated dry-autoclaved sample to have the highest digestibility.     

Changes in protein nutritional quality in fresh and recombined ultra high temperature treated milk during storage

The objective of this study was to determine the changes in nutritional quality of protein in stored UHT milk. Commercial fresh and recombined ultra high temperature (FUHT and RUHT respectively) treated milk samples were used. Pasteurized milk (P-milk) samples were used for comparison. Milk samples were freeze-dried for the use in diet formulation. Pasteurized milk samples were freeze-dried within 24 h of production. FUHT and RUHT milk samples were freeze-dried after production (zero time), 3 and 6 months of storage at 37 degrees C. Three nitrogen balance experiments were done at zero time, after 3 and 6 months of storage. The diet used in all experiments were similar in composition except for protein source. In each experiment egg white (low protein), casein (control), P-milk, and either 0, 3 or 6 months old FUHT and RUHT milk samples were used as the source of protein in the diets. In each experiment 30 (six for each diet) male Sprague-Dawley rats were used. Apparent digestibility (AD), true digestibility (TD), biological value (BV), and net protein utilization (NPU) were calculated for protein in casein and all milk samples. The nutritional quality of protein in FUHT milk before storage was similar to that of protein in pasteurized milk, but it decreased during storage for 3 months and then remained at the same quality up to 6 months of storage. BV and NPU of protein in FUHT milk after storage for 3 and 6 months were lower than that of protein in pasteurized milk by 4% (not significant) and 5% respectively. On the other hand, the nutritional quality of protein in RUHT milk before storage was lower than that of protein in pasteurized milk and remained at the same level after storage for 3 months: however, it decreased significantly after storage for 6 months. AD and TD of protein in RUHT milk stored for 6 months were lower than that of protein in pasteurized milk by 5% and BV and NPU were lower than that of protein in pasteurized milk by 9 and 12% respectively. The above reduction in nutritional quality of protein in UHT milk may be of significant value in feeding young children who might be dependent on this type of milk in their diet.     

Changes in protein nutritional quality in fresh and recombined ultra high temperature treated milk during storage

The objective of this study was to determine the changes in nutritional quality of protein in stored UHT milk. Commercial fresh and recombined ultra high temperature (FUHT and RUHT respectively) treated milk samples were used. Pasteurized milk (P-milk) samples were used for comparison. Milk samples were freeze-dried for the use in diet formulation. Pasteurized milk samples were freezedried within 24 h of production. FUHT and RUHT milk samples were freeze-dried after production (zero time), 3 and 6 months of storage at 37°C. Three nitrogen balance experiments were done at zero time, after 3 and 6 months of storage. The diet used in all experiments were similar in composition except for protein source. In each experiment egg white (low protein), casein (control), P-milk, and either 0, 3 or 6 months old FUHT and RUHT milk samples were used as the source of protein in the diets. In each experiment 30 (six for each diet) male Sprague-Dawley rats were used. Apparent digestibility (AD), true digestibility (TD), biological value (BV), and net protein utilization (NPU) were calculated for protein in casein and all milk samples. The nutritional quality of protein in FUHT milk before storage was similar to that of protein in pasteurized milk, but it decreased during storage for 3 months and then remained at the same quality up to 6 months of storage. BV and NPU of protein in FUHT milk after storage for 3 and 6 months were lower than that of protein in pasteurized milk by 4% (not significant) and 5% respectively. On the other hand, the nutritional quality of protein in RUHT milk before storage was lower than that of protein in pasteurized milk and remained at the same level after storage for 3 months: however, it decreased significantly after storage for 6 months. AD and TD of protein in RUHT milk stored for 6 months were lower than that of protein in pasteurized milk by 5% and BV and NPU were lower than that of protein in pasteurized milk by 9 and 12% respectively. The above reduction in nutritional quality of protein in UHT milk may be of significant value in feeding young children who might be dependent on this type of milk in their diet.     

Daily food intake and digestibility in rats.

The present work with growing rats was undertaken to study the effect of daily food intake (DFI) on true protein digestibility (TD), and apparent digestibility of dry matter (DM), energy (DE), starch, soluble dietary fibre (SDF) and insoluble dietary fibre (IDF). The design involved two different dietary combinations, barley + rapeseed meal (diet 1) and oats + wheat bran (diet 2). A slight but significantly negative relationship was seen between DFI and TD on diet 1 while no such relationship was found on diet 2. Although significant, DFI influenced DM digestibility of both diets only slightly. A similar situation could also be seen for the effect of DFI on DE. The digestibility of starch was significantly affected by DFI on both diets even though the lowest values were as high as 0.994. SDF digestibility (fermentability) was not influenced by DFI when the rats were given diet 1, while there was a significant negative effect of DFI on digestibility of SDF when diet 2 was given. The digestibility (fermentability) of IDF was not affected by DFI on either of the two diets. The results confirm the existence of a weak negative relationship between DFI and digestibility of a range of nutrients although the effect seems to be only marginal and of no importance under practical feeding conditions.     

某蛋白质粉的营养价值评价

目的了解某蛋白质粉的蛋白质营养价值。方法采用化学和生物学方法测定和分析某蛋白质粉的营养价值,并与酪蛋白进行比较。根据国标测定蛋白质粉的化学成分。单笼饲养50～70g的SPF级初断乳Wistar大鼠36只,适应环境后根据体重随机分为3组,分别为无氮组以及含蛋白质10.4%的酪蛋白组和含蛋白质10.5%的蛋白质粉组。按照AOAC（美国官方分析化学师协会）标准给予饲料,根据食物摄入量、体重增加量和饲料中的蛋白质含量计算出蛋白质功效比值（PER）。使用代谢笼,单笼饲养180 g左右的SPF级幼年Wistar大鼠12只,分为无氮组和蛋白质粉组,每天收集每只大鼠的粪便和尿液,测定其中的蛋白质含量,计算出表观消化率（AD）和真消化率（TD）。结果化学方法得出受试蛋白质粉的必需氨基酸（EAA）占其氨基酸总量的41.74%,EAA组成与FAO/WHO模式接近,支链氨基酸（BCAA）含量约占氨基酸总量的20%,蛋白质的氨基酸评分（AAS）、化学评分（CS）为69.1、59.8。生物学方法得出受试蛋白质粉的PER为2.22,蛋白质粉组大鼠的食物利用率（32.93%）与酪蛋白组（33.01%）比较,差异无统计学意义（P〉0.05）。受试蛋白质粉的AD和TD分别为93.90%和94.27%,生物价（BV）为90.45,蛋白质净利用率（NPU）为85.34%。结论受试蛋白质粉的EAA和BCAA含量较高,生长价值与酪蛋白类似,受试蛋白质粉的氨基酸评分、消化率、生物价、蛋白质净利用率等评价指标均高于大豆蛋白,与鱼肉、牛肉等动物性食品的蛋白质营养价值接近,说明受试蛋白质粉的蛋白质营养价值高,是良好的蛋白质来源。     

Effect of fiber-rich brown seaweeds on protein bioavailability of casein in growing rats

The effect of three subtropical fiber-rich brown seaweeds, Sargassum hemiphyllum (Turn.) C. Ag., Sargassum henslowianum C. Ag. and Sargassum patens Ag., on protein bioavailability of casein were evaluated by growing rats. The effect of the fiber-rich seaweeds was determined by comparing the net protein ratio (NPR), true protein digestibility (TD), nitrogen balance (NB), biological value (BV), net protein utilization (NPU), and fecal and urinary nitrogen loss of seaweed-based diet groups with those of the cellulose-based control group. There were no significant differences on NPR and urinary N loss in all diet groups. However, the values of TD (range 85.6-89.6%), BV (range 96.9-97.5%), NPU (range 83.5-86.8%) and NB (range 145-150 mg/rat/day) in all seaweed-based diet groups were significantly (p<0.05, one-way ANOVA, Tukey-HSD) lower than those of the control group. On the contrary, the fecal weight (range 5.59-6.30 g/rat/day) and fecal nitrogen (N) loss (range 31.1-41.2 mg/rat/day) of rats fed seaweed-based diets were significantly (p<0.05, one-way ANOVA, Tukey-HSD) higher than that of the control one. However, the differences on the body weight gain and weight of internal organs including liver, kidney and spleen between the seaweed-based diets and control groups were insignificant except that the weight of caecum of rats fed seaweed-based diets was significantly (p<0.05, one-way ANOVA, Tukey-HSD) higher than that of control group. The possible mechanism of fiber-rich brown seaweeds in affecting the protein bioavailability of casein and their related nutritional implications were discussed.     

Determination of amino Acid content and protein quality of complementary food produced from locally available food materials in ondo state, Nigeria

Protein-energy malnutrition is increasing among children in developing countries due to low nutrient density of traditional complementary diets. Therefore, this study aimed at determining the protein quality of a complementary food produced from cooking banana fruits and bambara groundnut seeds. The cooking banana and bambara groundnut seeds are locally available in both urban and villages markets in Nigeria. The cooking bananas (CB) and bambara groundnut (BG) seeds were processed into flours using standard procedure. The flours were mixed in a ratio of 70:30 (CBR1) and 60:40 (CBR2) of CB and BG respectively. A commercial weaning food (Nutrend) and traditional weaning food, ogi(corn gruel), were used as control food samples. The amino acid content and protein quality of the food samples were determined using standard procedures. Glutamic acid (CBR1 = 4.353 g/100g, CBR2 = 5.804 g/100g) was the highest while cysteine (CBR1= 0.252 g/100g; CBR2 = 0.336 g/100g) was the lowest of the amino acids in the food samples. The amino acids composition increased as the percentage supplementation of bambara ground nut increased in the mixtures. The formulated food sample showed that CBR1 and CBR2 met 31.8% and 42.4% respectively of the recommended dietary allowance (RDA) fulfilment of essential amino acids. The biological value (BV) of CBR2 (90.5%) was significantly high when compared with CBR1 (75.9%) and ogi (52.4%). There was no significant difference between the BV of CBR2with the BV of Nutrend (93.8%). Also, the net protein utilisation (NPU), total digestibility (TD), protein efficiency ratio (PER), feed efficiency ratio (FER) and nitrogen retention (NR) of CBR2 were within a similar range as those for Nutrend. As for the haematological variables, there were no significant differences between those fed the formulated diets and the control samples. The rate of weight gain for the animals fed with CBR2 food sample was higher than those fed with CBR1 and ogi but were lower than those for animals fed with Nutrend and casein. The study established that the CBR2 samples contained.     

The effect of type and level of protein, fibre and starch on nitrogen excretion patterns in rats

1. Three series of nitrogen balance experiments were performed with growing rats to test the effect of type and level of protein, fibre and starch on N excretion patterns. The design involved eighteen treatments in a 3 X 3 X 2 factorial experiment with five rats per dietary treatment. The eighteen treatments resulted from a combination of three protein treatments, three fibre treatments and two starch treatments. Protein treatments consisted of one level (15 g N/kg DM) of casein fortified with methionine, a protein of high digestibility, and two levels (15 and 20 g N/kg DM) of autoclaved brown beans (Phaseolus vulgaris), a protein source of low digestibility. The fibre treatments were two levels of cellulose powder and one level of barley hulls. The two starch treatments were autoclaved potato starch and autoclaved and raw potato starch (1:1, w/w). 2. The inclusion of raw potato starch reduced true protein digestibility markedly when the protein source was casein, but the corresponding biological values were increased significantly with this treatment. This strongly indicated a movement of urea from the blood to the intestines. This assumption was also supported by significantly lower blood urea concentrations in animals given raw starch. The influence of raw starch on true protein digestibility was, however, significantly less when cellulose and barley hulls were included. This is probably due to reduced transit time from fibre inclusion. The nature of the gut contents also supported this hypothesis. 3. The inclusion of raw potato starch when brown beans were the source of protein had much less effect on true protein digestibility and biological value than when casein was the protein source. This was probably due to the low digestibility of DM and protein in this food leaving sufficient energy and protein for maximum microbial growth. The inclusion of fibre also had little effect on N excretion patterns with the brown-bean diets. 4. An increase in the level of brown bean inclusion reduced true protein digestibility only on the diets containing raw starch whereas the biological value was consistently reduced regardless of starch treatment. The lower biological values were associated with significantly higher blood urea concentrations. Increasing the level of brown bean inclusion also resulted in higher fresh weights of caecum, colon and contents. 5. The present work proves that, through dietary manipulation, it is possible to affect nitrogen excretion patterns in rats.     

The effects of feed intake and purified cellulose on the endogenous ileal amino acid flow in growing pigs.

The effects of level of feed intake (0.8, 1.2 and 1.6 kg/d) and body-weight of the pig (49 and 92 kg) in Expt 1, and dietary neutral-detergent fibre (NDF; 30, 60, 90, 120 and 150 g/kg) in Expt 2 on the endogenous ileal flow of amino acids (AA) and nitrogen were studied with protein-free diets into which purified wood cellulose was incorporated at the expense of maize starch. In Expt 1, one of the protein-free diets containing 90 g NDF/kg was used. Female pigs were fitted with a simple 'T' cannula at the terminal ileum. In Expt 1, the endogenous ileal AA and N flow, expressed as g/kg dry matter (DM) intake, decreased significantly (P < 0.05) with increasing DM intake, except for proline. By contrast, the values expressed as g/d remained constant. There was no significant difference in endogenous ileal flow (P > 0.05) between initial body-weights of 45 and 90 kg except for histidine, isoleucine, phenylalanine, threonine, valine and serine, in which the ileal flow determined at the higher body-weight was significantly higher (P < 0.05). In Expt 2, the effects of dietary cellulose levels on the endogenous ileal flow of AA and N were not significant (P > 0.05), although the values tended to increase as dietary cellulose levels increased for most AA and for N. It is concluded that the daily endogenous ileal flow of AA and N remains relatively similar at different DM intake and cellulose levels. Therefore, correction of apparent ileal digestibility of AA and N to the true ileal digestibility should be made with the endogenous ileal flow values expressed on a daily amount basis, not the values expressed on a DM intake basis.     

Effect of pectin structure on protein utilization by growing rats

The effect of pectins' molecular weight (MW) and degree of esterification (DE) on apparent digestibility (D), net protein utilization (NPU) and biological value (BV) of casein were tested. The pectins prepared differed in MW and DE respectively as follows: P-1 (180,000, 73%); P-2 (300,000, 28%); P-3 (60,000, 74%) and P-4 (75,000, 40%) and were fed as 10% of a purified diet containing 10% casein to growing male rats for 10 days. All preparations decreased D, with P-2 and P-4 showing milder effects than P-1 or P-3. Increased NPU was observed with pectins of low NW and/or DE, being significant only with P-4. Diets containing P-2, P-3 or P-4 had higher BV for casein than the pectin-free diet. Feeding these pectins in a protein-free diet did not cause a significant change in the rats' body N content. Thus, the increase in the BV of casein was attributed to improvements in the pattern of amino acids absorbed by rats fed pectins with low MW and/or low DE.     

The effect of protein levels on the response of weanling rats to dietary pectin

We have previously proposed that the inhibiting effects of pectin on feed consumption and growth might be due in part to the reduction it causes in protein digestibility. The present work was intended to test this hypothesis by feeding higher levels of protein in order to compensate for the lower digestibility. We fed diets containing 10, 20 and 30% casein (initial levels) and 0, 4.8, 16.7 and 28.6% pectin (by diet dilution). Despite the higher casein levels, pectin strongly inhibited the animals' feed intake, growth, protein efficiency ratio (PER), net protein ratio (NPR) and net protein utilization (NPU) as well as protein and energy digestibilities. Apart from determining the base (zero pectin) level of the various parameters measured, the dietary casein level in itself did not influence the effect of pectin on feed intake, digestible energy intake, protein digestibility, body weight growth or parameters of protein utilization such as PER, NPR and NPU. We thus cannot conclude that these effects of pectin were to any major extent secondary to the reduction in protein digestibility observed in these animals.     

Utilization and requirement of dietary protein taking into account the dermal and miscellaneous nitrogen losses in Japanese women

Utilization and requirement of mixed protein in the conventional Japanese diet and the obligatory integumental and miscellaneous nitrogen losses were measured in female subjects. Twelve female students aged 18 to 24 years were given conventional low-protein diets at N intake levels of 50, 70, and 90 mg/kg/day for 10 days. Constituents of the diets corresponded to those of average intake of the Japanese in recent years (1982). N balances were estimated and regression equations between N intake (X) and N balance (Y) were calculated by the multiple level-constant variation method. The equation was Y = 0.426X - 40.0 (n = 36, r = 0.615, p less than 0.01) and the intersection of the regression line with zero nitrogen balance was 93.9 +/- 14.3 mg N/kg/day. The mean digestibility was 92.2 +/- 4.7%. In another experimental group, nitrogen losses due to hair, nails, and menstruation in ten Japanese women were 0.624 +/- 0.172, 0.020 +/- 0.005, and 1.76 +/- 0.68 mg/kg/day, respectively. In a third experimental group, mean of the integumental N losses was 2.8 mg/kg/day in both the subjects given a low-protein diet (19 women) and an ordinary-protein diet (4 women). It increased to 12.7 mg N/kg/day when subjects exercised in summer (4 subjects). The protein requirement in the conventional Japanese diet estimated as the sum of the mean requirement of dietary protein and obligatory dermal and miscellaneous nitrogen losses in Japanese women was 99.1 mg N/kg/day or 0.62 g protein/kg/day. The net protein utilization (NPU) of the proteins at the N intake level for N equilibrium was estimated as 48.     

Nutritional improvement of Lobia (Phaseolus vulgaris) by supplementation with poultry, mutton and beef meat

The study was conducted to determine the nutritional value of Lobia (Phaseolus vulgaris) in raw and cooked forms and as effected by supplementation with different kinds of meat, i.e. poultry, mutton and beef at 10, 15 and 20% levels. Nutritional assessment of all the Lobia-containing diets (without or with supplementation) was made by chemical analysis as well as through rat assay. Lobia contained 20.43% of protein. Cooking resulted in minor changes in nutrients. It had 0.54% lysine which was reduced to 0.29% on cooking. All other amino acids also showed losses during cooking. Protein efficiency ratio (PER) of diets containing raw Lobia was 1.05 and significantly (P < 0.05) improved to 1.47 on cooking. True digestibility (TD) and net protein utilization (NPU) also showed a significant (P < 0.05) improvement in the case of cooked Lobia. Supplementation of Lobia with 20% of mutton or beef meat improved the PER significantly (P < 0.05) over unsupplemented diet containing cooked Lobia only. TD was improved from 74.9% in cooked to 84.3% in diets containing 20% mutton. Similarly NPU improved as a result of meat supplementation, from 40.7% in cooked to 53.4%. Higher PER, TD and NPU values were observed in diets containing Lobia supplemented with 20% level of mutton or beef.     

Effect of cooking and supplementation with different kinds of meats on the nutritional value of mash (Vigna mungo)

The study was conducted to determine the nutritional value of mash (Vigna mungo) in raw and cooked forms and as effected by supplementation with different kind of meat, i.e. poultry, mutton and beef at 10, 15 and 20% levels. Nutritional assessment of all mash-containing diets (without or with supplementation) was made by chemical analysis as well as through rat assay. Mash contained 23.83% protein. Cooking resulted in minor changes in nutrients. Mash had 1.79% lysine which was reduced by 35% on cooking. All other amino acids also showed losses during cooking. Protein efficiency ratio (PER) of diet containing raw mash was 1.9% and cooking improved it to 2.8%. True digestibility (TD) also showed a significant improvement. Supplementation of mash with different kinds of meat did not improve the PER significantly over unsupplemented diet containing cooked mash only. TD, however, was improved from 74.89% in cooked to 75.58-87.06% in supplemented diets. Similarly net protein utilization (NPU), as a result of meat supplementation, improved from 43.54% in cooked to 42.88%-51.96%. Higher PER, TD and NPU values were observed in diets containing mash supplemented with 20% level of different meats.