The present study was undertaken to provide detailed information about the effect of dietary fibre (DF) level on the development of the digestive tract, on nutrient digestibility and on energy and protein metabolism of pigs housed in low (13') or high (23") thermal environments. Low-and high-fibre diets (59 v. 268 g DF/kg DM) were studied in three balance periods with fktulated pigs in the weight range 45-120 kg. Heat production was measured using open-circuit respiration chambers. Pea fibre and pectin were used to adjust the D F level in the high-fibre diet. Per kg empty body weight the stomach, caecum and colon and the length of colon were significantly greater in pigs consuming the high-fibre diet than in those on the low-fibre diet. Pigs kept at low temperature had significantly heavier caecums than those kept at the high temperature. Digestibilities of protein, DM and energy were lowest for the high-fibre diet. Only minor amounts of NSP and its constituent sugars were degraded anterior to the ileum, whereas in the hind-gut the fermentation of the total NSP fraction was high, being 0.77 for the high-fibre diet and 0.59 for the low-fibre diet. Feeding the high-fibre diet increased the flow of digesta through the terminal ileum %-fold and an extra 460 g organic matter was fermented daily in the hind-gut compared with pigs fed on the low-fibre diet. The amount of retained energy as a proportion of metabolizable energy decreased in relation to the amount of energy fermented in the hind-gut. Based on the present data it was estimated that the relative value of energy derived from hind-gut fermentation was 0.73 in comparison with energy enzymically digested in the small intestine. There was negligible effect of the temperature -fibre interaction on energy metabolism. However, it could be calculated that the decrease in temperature from 23" to 13" was associated with an increase in heat production by 2.9 MJ/pig per d.

I . Three factors were investigated which influence blood urea content, namely the protein content in the diet, the time after feeding and the protein quality of the diet.2. T o investigate the relationship between the protein content in the diet and the blood urea content, seventeen experiments with rats given increasing amounts of protein in the diet were carried out. The experimental results show that there is a positive correlation (r = 0.95) between the protein content in the diet and the blood urea content.3. For investigation of the influence of time after feeding on the urea content in the blood, a pig was used having a catheter in the portal vein for blood sampling at intervals. The results from this experiment showed that the blood urea content increases for the first 3-4 h after feeding and thereafter reaches a plateau. 4.To use blood urea measurement as a technique for assessing protein quality it is necessary to work under standardized conditions, especially in regard to the two factors just discussed. 5 . Forty-two feeding-stuffs of widely differing quality were used in nitrogen balance trials with rats. The results showed that there is an inverse relation between the blood urea content and the biological value of the diet which is sufficiently accurate (coefficient of variation = 53 yo) to provide ausefulmethod for the predictionof protein quality from measurement of urea levels.The blood urea content is commonly considered in ruminants to reflect the protein quality of the diet, but this method has scarcely been used with monogastric animals. The use of blood urea levels as an index of protein quality depends on the control of several factors, some of which are discussed in this paper.In experiments with growing rats and pigs, Munchow & Bergner (1968) found a very high negative correlation between the biological value (BV) of the feed and the blood urea content. The correlation coefficients were 0'99 and 0.96 for rats and pigs respectively, egg protein being used as a reference protein. Also, Munchow & Bergner (1968) found that the blood urea content increased with the protein content in the diet. I n their experiments the urea content increased by 2.4 units each time the rats were supplied with another 10 mg nitrogenld, and they concluded that the blood urea content depends on both the quality and the quantity of the protein supplied in the diet. However, the same authors found no connexion between the weight of the animals and the blood urea content. Fonnesbeck & Symons (1969), in experiments with horses, also showed that the blood urea content depends first on the protein quantity and quality in the diet, but can be affected also by renal failure. In experiments with suckling pigs, Pastuszewska (1967) obtained the same results. This relationship is consistent with the demonstration that an increase in protein content effects a decline in

With the aim of improving the nutritive value of an important grain legume crop, a chimeric gene specifying seed-specific expression of a sulfur-rich, sunf lower seed albumin was stably transformed into narrow-leafed lupin (Lupinus angustifolius L.). Sunf lower seed albumin accounted for 5% of extractable seed protein in a line containing a single tandem insertion of the transferred DNA. The transgenic seeds contained less sulfate and more total amino acid sulfur than the nontransgenic parent line. This was associated with a 94% increase in methionine content and a 12% reduction in cysteine content. There was no statistically significant change in other amino acids or in total nitrogen or total sulfur contents of the seeds. In feeding trials with rats, the transgenic seeds gave statistically significant increases in live weight gain, true protein digestibility, biological value, and net protein utilization, compared with wild-type seeds. These findings demonstrate the feasibility of using genetic engineering to improve the nutritive value of grain crops.

The present study was undertaken to provide detailed information about the effect of fibre source (pea fibre, wheat bran or oat bran) at inclusion levels of 0,187 and 375 g/kg diet on the development of the digestive tract, nutrient digestibility and energy and protein metabolism in broiler chickens. Heat production was measured using open-air-circuit respiration chambers. Diets with increasing levels of pea fibre decreased the DM in droppings and increased excreta output (25fold) relative to DM intake. Adaptation to increased dietary fibre levels included increases in the size of the digestive system, with pea fibre exerting a stronger impact than wheat bran or oat bran. The length of the intestine, and particularly the length and weight of the caecum, increased with the fibre level. The digestibility of all nutrients also decreased with increasing fibre level. The decrease in the digestibility in relation to NSP for the three fibre sources was bigger for oat bran (0.0020 per g dietary NSP) than for pea fibre and wheat bran (04014 and 0.0016 per g dietary NSP) indicating that the cell walls in oat bran (aleurone and subaleurone) had a significant negative effect on the digestibility of cellular nutrients, i.e. protein and fat. The degradation of the NSP constituents was far lower in chickens than found in other animal species such as pigs and rats, thus supporting the view that chickens do not ferment fibre polymers to a great extent. Excretion of organic acids (mainly lactic acid and acetic acid) accounted for up to 2% of metabolizable energy (ME) intake with the highest excretion for the high-fibre diets. H, excretion was related to the amount of NSP degraded and indicated higher microbial fermentation with increasing fibre levels. The chickens' feed intake responded to a great extent to dietary ME concentration but expressed in terms of metabolic body size (W0'75) ME intake was depressed at the high fibre levels. Dietary NSP was able to explain between 86 YO (oat bran) and 96 YO (pea fibre) of the variation in ME concentration.The amount of energy available from fermentation of NSP appears to reach a maximum of 42 kJ/d independent of fibre source and level. Expressed in relation to M E intake the NSP fermentation contributed 3-4 YO. With increasing fibre intake the partitioning of retained energy between body protein and body fat changed in favour of protein.Gutfill: Heat increment: Non-starch polysaccharides: FermentationThe feed ingredients used in poultry diets are mostly of vegetable origin. Plant materials are rich sources of carbohydrates, i.e. low-molecular-weight sugars, starch and NSP, the latter being resistant to digestive enzymes. However, the NSP fraction can, to a certain degree, be broken down by the microbial flora permanently colonizing the gastrointestinal (GI) tract. The end-products of the microbial degradation are various gases (H2, CO,, CH,), lactic acid and short-chain fatty acids (SCFA). The SCFA produced are rapidly absorbed * For reprints.-f Visiting scientist from the Northwest Pla...

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The caecal content of short-chain fatty acids (SCFA; acetic, propionic and butyric acid), caecal pH, fermentability and dry matter digestibility (DMD) were examined through balance experiments in rats fed 1 1 various indigestible carbohydrates. The following carbohydrate sources were incorporated into test diets: cellulose, oat husk, wheat bran, oat bran, pea fibre, linseed fibre, low methoxylated (LM)-pectin. guargum, 8-glucans, neosugar and raffinose. The indigestible carbohydrates, except for those in wheat bran, oat husk and cellulose, were highly fermented, ie > 90%. Caecal pH varied between 5.6 and 7.8, with neosugar and raffinose causing the lowest pH and the fibre-free diet and the diet with oat husk the highest. The caecal pool sizes of SCFA were highest with raffinose, P-glucans, LM-pectin, guargum and linseed fibre (335400 pmol) while pea fibre, wheat bran, oat bran and neosugar gave intermediate levels (137-227 pmol). The pool size with oat husk and cellulose was similar as with the basal diet ( 4 M 4 pmol). A high proportion of propionic acid was obtained with guargum and linseed fibre, whereas acetic acid was the predominant product in case of LM-pectin. On the other hand, linseed fibre gave a remarkably low proportion of butyric acid. The quantity fermented and caecal pH correlated well to the amount of SCFA with most materials (r = 0.96 and r = -0.87, respectively), an exception was neosugar and in case of fermentability also oat bran. DMD values with most of the easily fermented carbohydrates were high (> 96 YO).Exceptions were diets with P-glucans and oat bran which caused low DMD values, about 93 YO. It is concluded that indigestible carbohydrates may differ in ability to lower caecal pH and to form SCFA during fermentation.

Nutrient composition of eight commonly consumed spices of South India was analysed. Spices analysed were red chillies (Capsicum annum), black pepper (Piper nigrum), coriander seeds (Coriandrum sativum), cumin seeds (Cuminum cyminum), garlic (Allium sativum), asafoetida (Ferula foetida), dry ginger (Zingiber officinale) and ajowan (Carum copticum). The nutrients analysed were proximate principles, minerals, starch, sugars, dietary fibre components, tannins, phytic acid, enzyme inhibitors and amino acids. Dry ginger, ajowan and asafoetida had high calcium (1.0-1.5%) and iron (54-62 mg/100 g) levels. The tannin content of spices was also high (0.9-1.3% DM). Dietary fibre ranged from 14-53%. Spices had appreciable amounts of essential amino acids like lysine and threonine. A survey revealed the average per capita consumption of spices to be 9.54 g and at that level, the nutrient contribution from spices ranged from 1.2 to 7.9% of an average adult Indian male's requirement for different nutrients.

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