bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of Iron, Copper, Manganese and Nickel during Maize Grain Maturation
Authors: Horvatić M. , Gačić M. , Vedrina‐Dragojević I.
Published: March 2003

Dynamics of the accumulation of iron, copper, manganese and nickel, as well as their relationships with total ash, crude proteins and total dry matter during maize grain maturation were investigated. The investigation was carried out on normal maize hybrids grown under the same topographical and agrotechnical conditions. The amounts of particular microelements in the fresh grain matter increased significantly up to a late stage of dough maturation. The dynamics of their accumulation correlated positively and significantly with deposition of total dry matter, total ash and crude proteins, and were consistent with biological needs of the maize grain during development. The amounts of microelements expressed on a dry matter basis decreased significantly in a late stage of milky grain maturation. Further fluctuations were not significant. The correlation between particular microelements during grain maturation was positive and significant, as well as the correlation of particular microelements with crude proteins and total ash in the grain dry matter.
Does Salinity Inhibit Alfalfa Leaf Growth by Reducing Tissue Concentration of Essential Mineral Nutrients?
Authors: Esechie H. A. , Rodriguez V.
Published: March 2003

The increased salinity of arid and semi‐arid lands has become a problem of great concern in agriculture. The possibility that the inhibition of leaf growth in alfalfa (Medicago sativa) growing under saline conditions may be associated with a reduction in ion concentration in the leaf was investigated. Seeds of alfalfa cv. Buraimi were sown in PVC cylinders filled with loamy sand and arranged in large pots embedded in the soil with the rim just above the soil surface. This arrangement simulated plants grown under field conditions. Seedlings were irrigated with saline (12.2 dS m−1) and nutrient solutions (full strength or 20 times dilution) twice weekly. After 6 weeks the plants were harvested and separated into roots, stem and leaves. The leaves were further separated into lamina and petioles and analysed for the major and minor nutrient elements. Salinization significantly reduced the fresh weights of the roots, stem and leaves as well as the concentration of N, K, Ca and Mg in the leaf tissue. With the exception of Cu concentration, which was enhanced by salinity, all the micronutrients (B, Zn, Mn and Fe) had reduced concentrations in the leaves of salinized alfalfa. The application of an external nutrient solution, especially the full‐strength solution, produced an increase in leaf growth and leaf nutrient element concentration. On the basis of these results it was concluded that reduced leaf nutrient concentration may be one of the primary causes of the inhibition of leaf growth that was characteristic of alfalfa growing under salinity stress.
Dry Matter Partitioning in Linseed (Linum usitatissimum L.)
Authors: Hassan F. U. , Leitch M. H. , Ahmad S.
Published: March 2003

A pot experiment was conducted at University of Wales Aberystwyth, UK, Frongach field station to evaluate the effects of sowing dates on the dry matter partitioning of linseed. Root, stem and capsule (boll) weight increased progressively as sowing was delayed up to third sowing (19 April) but showed a gradual decrease when sowing was further delayed. The contribution of each of the three parts to total weight did not respond to sowing date in any consistent manner. The total dry matter per plant followed a similar pattern to the dry matter of plant parts, which increased with sowing up to third sowing (19 April) and then decreased when sowing was further delayed. Dry matter accumulation per day degree > 4 °C also increased as sowing was delayed with a peak at third sowing (19 April). Dry matter accumulation per day degree is concluded to be directly related to the total day degrees received during the growth period.
Variation in Photosynthetic Traits in Barnyard Millet (Echinocloa frumentaceae) Genotypes
Authors: Subrahmanyam D. , Rathore V. S.
Published: March 2003

A field experiment was conducted to assess the genotypic variability in 41 divergent barnyard millet (Echinocloa frumentaceae L.) genotypes. A high degree of variation was observed for photosynthesis and other related characteristics. However, for specific leaf weight (SLW), the differences amongst genotypes were non‐significant. The seasonal means of photosynthetic rate (A), stomatal conductance (gs), transpiration (E), A/Ci ratio and total dry matter at harvest were positively and significantly correlated. None of the other parameters showed any significant relationship with total dry matter recorded at harvest. Leaf photosynthetic rate showed a positive but non‐significant relationship with SLW, and it is suggested that photosynthesis rate seems to be the best selection criterion in barnyard millet. A strong and positive relationship was observed between A/E ratio, A/Ci ratio and A/gs ratio, indicating that both A/Ci ratio and A/gs had a strong influence on the water use efficiency of the leaf.
Strahlungsnutzung durch Bestände ölreicher Körnerfruchtarten — Winterraps, Öllein und Sonnenblume im Vergleich
Authors: Aufhammer W. , Wägner W. , Kaul H.‐P. , Kübler E.
Published: March 2003

Radiation use by oil seed crops — a comparison of winter rape, linseed and sunflower

For the production of grain crops rich in oil, winter rape, linseed and sunflower are similarly suitable at many arable locations. We wanted to compare the extent to which radiation (PAR) is intercepted and utilized by the individual species for dry matter and yield production. For this purpose, a 2‐year field experiment comprising the factors genotype, N fertilization and soil tillage was conducted. For five phases of crop development, growth rates (CGR, RGR and NAR) and PAR utilization were calculated. At full ripeness, total dry matter, grain, oil and energy yields, the crop‐ and year‐specific PAR supply, its interception and utilization for dry matter production and the resulting energy binding were determined. Due to the different individual vegetation periods, the PAR supply of the crops differed. The crop assimilation areas also differed, with values for winter rape and sunflower higher than those for linseed. The yield productivity of winter rape and sunflower was also higher than that of linseed. N fertilization increased yield to different extents for the different crops. On average, winter rape and sunflower produced the same amounts of dry matter and energy yield. Due to a higher harvest index, sunflower had the highest grain yield, and because the oil concentration in grain was comparatively high sunflower produced the highest oil yield, too. Under cool and wet climate conditions, however, the productivity of sunflower is offset by a relatively high yield risk because of uncertain ripening. The highest PAR utilization by linseed did not compensate for its very short vegetation period in combination with the lowest PAR interception.
Effects of Water Deficit on the Dynamics of Flowering and Fruit Production in Capsicum chinense Jacq in a Tropical Semiarid Region of Venezuela
Authors: Jaimez R. E. , Vielma O. , Rada F. , García‐Núñez C.
Published: March 2003

The degree of crop sensitivity to water deficit, during the different developmental stages of a plant, is an important aspect to consider in tropical semiarid regions. The effect of water deficit on flowering dynamics and fruit production of sweet pepper (Capsicum chinense) was evaluated under several water regimes, during three consecutive years. A complete randomized block design with three replicates was employed. Flowering dynamics and fruit production were measured weekly, and water potentials were obtained twice during the experiments. For all years, flowering began at approximately 70 days after transplanting. In the most favourable year (trial 1996), there were no differences in total flower and fruit production in terms of irrigation frequency. For the other less favourable years, flowering and fruit production were significantly different between irrigation frequencies. Our results show that low water availability, prior to flowering, reduces the number of flowers produced and retards the occurrence of maximum flowering. On the other hand, a water deficit during the period between flowering and fruit development reduces final fruit production. This suggests that a water deficit during this last stage affects final yield to a greater extent.
Effects of Exogenous Injection of Different Sugars on Leaf Photosynthesis, Dry Matter Production and Adenosine 5′‐Diphosphate Glucose Pyrophosphorylase (AGPase) Activity in Sweet Potato, Ipomoea batatas (Lam.)
Authors: Kadowaki M. , Kubota F. , Saitou K.
Published: March 2003

Solutions of sucrose, glucose and fructose were artificially injected into the stems of sweet potato plants. The effects of solution injection on both dry matter production and the activity of adenosine 5′‐diphosphate glucose pyrophosphorylase (AGPase) in tuberous roots were investigated and compared. The total weight of carbon (TC) artificially and photosynthetically supplied to a plant during the treatment period of 40 days was 0.987–1.869 times the weight of photosynthetically assimilated carbon alone. At the final sampling time, the dry matter weight of tuberous roots in the plants injected with sugar solutions showed a 2.73–9.13‐fold increase over that of the control plant. The root weight linearly increased with TC. The activity of AGPase was also enhanced by solution injections, with 27–63 % increases compared to the control, but was not significantly related to TC. The injection of sugar solutions is concluded to have a dual effect on root production in sweet potato. One effect is that the increased sugar concentration in the plant increases AGPase and sink activities, and the other effect is that the increased carbon supply quantitatively promotes starch synthesis and accumulation in roots.
Effect of Different Crop Densities of Winter Wheat on Recovery of Nitrogen in Crop and Soil within the Growth Period
Authors: Blankenau K. , Olfs H.‐W.
Published: March 2003

Previous experiments have shown that, at harvest of winter wheat, recovery of fertilizer N applied in early spring [tillering, Zadok’s growth stage (GS) 25] is lower than that of N applied later in the growth period. This can be explained by losses and immobilization of N, which might be higher between GS 25 and stem elongation (GS 31). It was hypothesized that a higher crop density (i.e. more plants per unit area) results in an increased uptake of fertilizer N applied at GS 25, so that less fertilizer N is subject to losses and immobilization. Different crop densities of winter wheat at GS 25 were established by sowing densities of 100 seeds m–2 (Slow), 375 seeds m–2 (Scfp= common farming practice) and 650 seeds m–2 (Shigh) in autumn. The effect of sowing density on crop N uptake and apparent fertilizer N recovery (aFNrec = N in fertilized treatments − N in unfertilized treatments) in crops and soil mineral N (Nmin), as well as on lost and immobilized N (i.e. non‐recovered N = N rate − aFNrec), was investigated for two periods after N application at GS 25 [i.e. from GS 25 to 15 days later (GS 25 + 15d), and from GS 25 + 15d to GS 31] and in a third period between GS 31 and harvest (i.e. after second and third N applications). Fertilizer N rates varied at GS 25 (0, 43 and 103 kg N ha–1), GS 31 (0 and 30 kg N ha–1) and ear emergence (0, 30 and 60 kg ha–1). At GS 25 + 15d, non‐recovered N was highest (up to 33 kg N ha–1 and up to 74 kg N ha–1 at N rates of 43 and 103 kg N ha–1, respectively) due to low crop N uptake after the first N dressing. Non‐recovered N was not affected by sowing density. Re‐mineralization during later growth stages indicated that non‐recovered N had been immobilized. N uptake rates from the second and third N applications were lowest for Slow, so non‐recovered N at harvest was highest for Slow. Although non‐recovered N was similar for Scfp and Shigh, the highest grain yields were found at Scfp and N dressings of 43 + 30 + 60 kg N ha–1. This combination of sowing density and N rates was the closest to common farming practice. Grain yields were lower for Shigh than for Scfp, presumably due to high competition between plants for nutrients and water. In conclusion, reducing or increasing sowing density compared to Scfp did not reduce immobilization (and losses) of fertilizer N and did not result in increased fertilizer N use efficiency or grain yields.
Corn Genotypic Variation Effects on Seedling Emergence and Leaf Appearance for Short‐Season Areas
Authors: Begna S. H. , Smith D. L. , Hamilton R. I. , Dwyer L. M. , Stewart D. W.
Published: March 2003

Identifying corn (Zea mays L.) genotypes with faster rates of seedling emergence and leaf appearance is important in developing a corn crop with earlier canopy closure and better seasonal light interception. A greenhouse experiment was conducted twice to investigate whether corn genotypes known to vary in canopy architecture and yield potential differed in rates of seedling emergence and leaf appearance. The experiment was arranged in a randomized complete block design utilizing seven genotypes: five of the newly developed Leafy reduced‐stature (LRS) types (LRS1, LRS2, LRS3, LRS4 and LRS5), one conventional type [Pioneer 3979 (P3979)], and one late‐maturing big‐leaf (LMBL) type. Five seeds were planted in each pot and seedling emergence was recorded every day until all seeds emerged. Leaf appearance was recorded from seedling emergence until the plants reached anthesis. There was variability among the genotypes for both seedling emergence and leaf appearance rate. Mean seedling emergence values of greater than 90 % were achieved by four of the five LRS genotypes, and the LRS types generally emerged more rapidly than the others. Leaf appearance rate showed linear increases over time; however, LRS genotypes (in particular LRS3, LRS4 and LRS5) had more rapid leaf appearance rates than the others. The LMBL hybrid ranked last for both seedling emergence (<80 %) and leaf appearance rate. Rapid seedling emergence and leaf appearance by early‐maturing genotypes (LRS and P3979, especially LRS) may help these types of genotypes achieve earlier canopy closure and better use of the light available during the growing season, which is critical in a short growing season environment.
Changes in Certain Antioxidative Enzymes and Growth Parameters as a Result of Complete Submergence and Subsequent Re‐aeration of Rice Cultivars Differing in Submergence Tolerance
Authors: Sarkar R. K. , Das S. , Ravi I.
Published: March 2003

An experiment was conducted on the three indica rice (Oryza sativa L.) cultivars IR 42, CR 383‐10 and FR 13A, which are susceptible to submergence, submergence‐avoiding and tolerant to submergence, respectively. A deleterious effect of submergence was noted as both above‐ground dry matter accumulation and chlorophyll content decreased during submergence and subsequent re‐aeration. However, the rate of reduction was lower in the tolerant cultivar. The tolerant cultivar FR 13A maintained higher dry weight during submergence and subsequent re‐aeration and accumulated lower proline and malondialdehyde contents than the other cultivars. The activities of the enzymes catalase, peroxidase and superoxide dismutase, expressed on a per g fresh weight of leaves basis, were higher in FR 13A than in the other cultivars, both under water and 24 h after the initiation of re‐aeration. However, ascorbic acid oxidase activity was lower in FR 13A. The cultivar CR 383‐10, which has the capacity to accumulate more above‐ground dry matter under normal conditions, showed a greater elongation ability under submergence and was similar to the susceptible cultivar IR 42 in terms of enzyme activities and the other parameters investigated during submergence and subsequent re‐aeration.
An Analysis of Seasonal Effects on Leaf Nitrate Reductase Activity and Nitrogen Accumulation in Maize (Zea mays L.)
Authors: Kumar S. Naresh , Singh C. P.
Published: March 2003

The important enzyme in nitrogen (N) assimilation, nitrate reductase (NR), is an inducible enzyme influenced by many external (light, temperature, etc.) and internal (genotype) factors. The efficiency of the N assimilation system may vary with genotype and season. In the present study, the effects of season on NR activity in relation to N accumulation in maize plants were investigated. Six different cultivars of maize, namely Ganga‐11, Deccan‐103, Hi‐starch (hybrids), Arun, Manjari and Vijay (composites), were sown during the monsoon (88‐day crop duration) and in winter (150‐day crop duration). In vivo NR activity in the last fully expanded leaf (LFEL), and the N contents of the whole plant and the LFEL were estimated at seven phenological growth stages. Three different states of N metabolism in maize, namely (i) low NR activity per unit leaf area per unit time coinciding with high accumulation of N, (ii) high NR activity coinciding with low N accumulation, and (iii) low NR activity coinciding with low N accumulation, were noted. These results clearly demonstrate that the relationships between N uptake and accumulation parameters change with the season and crop growth stage and are subject to a genotypic influence. Thus it is necessary to evaluate genotypes under similar environments to select a genotype with high N use efficiency. As these relationships are growth dependent, care must be taken to evaluate them at a particular phenological stage rather than on the basis of days after sowing.
Interaction Amongst Soybean [Glycine max (L.) Merrill] Genotype, Soil Type and Inoculant Strain with Regard to N2 Fixation
Authors: Van Jaarsveld C. M. , Smit M. A. , Krüger G. H. J.
Published: March 2003

The nitrogen (N2)‐fixing bacterial inoculant strain for soybean [Glycine max (L.) Merrill] is not indigenous to South African soils. The interaction between soybean genotype, soil type and inoculant strain, however, has a definite influence on soybean production and compatibility should be optimized. This paper reports a growth chamber study using three different soybean genotypes (Barc‐9, Avuturda and Talana), three Bradyrhizobium japonicum inoculant strains (WB108, WB112 and WB1) and three soil types (Avalon, Arcadia and sand) to evaluate the effectiveness of N2 fixation by different genotype × soil type × inoculant strain combinations, using different measuring parameters. These parameters included nodule fresh mass (NFM), amount of N2 fixed (Pfix), as determined by the ureide method, seed protein content (SPC), average seed mass per plant (SMP) and average foliar N content (FNC). The comparison amongst the three‐way interactions, genotype × soil type × inoculant strain, did not differ significantly for the parameters used. Significant two‐way interactions were soil × inoculant for FNC, Pfix and SMP; soil × genotype for FNC and SMP, and inoculant × genotype for FNC (P < 0.05). The soil × inoculant strain interaction was significant for Pfix (P < 0.05). NFM, Pfix, FNC, SMP and SPC correlated positively with soil pH and negatively with soil clay content and soil NO3– and NH4+ content (P < 0.05). SPC was significantly different (P < 0.05) for soil type, genotype and inoculant strain. Pfix and NFM did not reflect the protein content of the seeds, indicating that nodule evaluation should be used with caution as a N2 fixation parameter. Low soil pH and high mineral N content inhibited N2 fixation. NFM correlated negatively with the clay content of the soil. This finding confirms that soybean production in South Africa can be improved by appropriate selection of genotypes and inoculant strains for their compatibility in different soils.
Effect of Phosphorus and Nitrogen Fertilization on Sunflower (Helianthus annus L.) Nitrogen Uptake and Yield
Authors: Zubillaga M. M. , Aristi J. P. , Lavado R. S.
Published: March 2003

Little is known about the effect of combined phosphorus and nitrogen (P‐N) fertilization on the N requirement of sunflower (Helianthus annus L.). This study was carried out to evaluate the effects of varying levels of P and N, as well as the interaction P × N, on the N uptake, yield and N apparent utilization efficiency under field conditions. Split‐plot design experiments were conducted in the mid‐western Pampas in Argentina. Four levels of N (0, 46, 92 and 138 kg N ha−1) and three levels of P (0, 12 and 40 kg P ha−1) were applied to two Typic Hapludolls over two growing seasons (1997–98 and 1998–99). N uptake and soil N‐NO3 contents were determined at the V7, R5 and R9 growth stages. The sunflower yield ranged from 2.5 to 5.0 Mg ha−1. The total N requirement was around 45 kg N Mg−1 grain, and this result suggests that it is not necessary to use different N requirements (parameter b) for fertilized crops when a yield response is expected. To achieve a 100 % yield maximum a N supply (soil plus fertilizer) of 181 kg N ha−1 at P40 was needed. However, at P0, the highest yield was about 80 % of the maximum yield with a N supply (soil plus fertilizer) of 164 kg N ha−1. P application increased the apparent use efficiency of the supplied N.
Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. ‘Early Cream Gold’)
Authors: Spurr C. J. , Fulton D. A. , Brown P. H. , Clark R. J.
Published: March 2003

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.
Heritability of muscular cathepsin B activity in Italian Large White pigs
Authors: Russo V , Buttazzoni L. , Baiocco C. , Davoli M. R. , Nanni Costa N. L. , Schivazappa O. C. , Virgili P. C.
Published: March 2003

Previous studies suggested that proteolysis lasting for many months after slaughtering could be responsible for excessive softness in dry‐cured hams. Also, the long‐term activity of muscle proteinases is mainly attributed to cathepsin B. Should an additive genetic component exist for the activity level of cathepsin B, such information could be used as a selection criterion for improving meat quality for dry‐cured ham production. Data on the growth rate, carcass composition, and meat quality of 234 Large White pigs raised in a test station under a &lsquo|quasi ad libitum' nutritive level and slaughtered at around 160 kg live weight were analysed using a
blup‐
mt‐animal model. The cathepsin B activity level showed a moderate heritability (0.23–0.28) in all analyses, and negative genetic correlations with daily gain (− 0.34 to − 0.52) and backfat thickness (− 0.40 to − 0.86), but, with large standard errors. These results suggest that a genetic component exists in explaining the variability of the cathepsin B activity level. Further studies are necessary to confirm the outcome and to investigate genetic correlations with other traits currently under selection.
Correlated responses to selection for large body size in oMt1a‐oGH mice: growth, feed efficiency and body composition
Authors: Parks K. R. , Eisen E. J. , Murray J. D.
Published: March 2003

Correlated responses were determined for growth, feed consumption, feed efficiency and body composition following short‐term selection for large 8‐week body weight in transgenic and nontransgenic mice. Replicate lines which either carried or did not carry the sheep metallothionein 1a‐sheep growth hormone transgene (oMt1a‐oGH) were established. The lines carrying the transgene at an initial frequency of 0.5 came from a high‐growth (TM) and a randomly selected (TC) background. The respective nontransgenic lines were identified as NM and NC. Control replicates (CC) came from the randomly selected background. During the selection process the transgene was activated by adding 25 mm ZnSO4 to the drinking water of all mice. Correlated responses were measured with (Z) and without (C) the addition of zinc. After seven and eight generations of selection, the frequency of transgenic mice in line TM had fallen sharply, whereas transgene frequency had risen moderately in TC. The reduced frequency of oMt1a‐oGH in the high‐growth genetic background may have been caused by a lower additive effect compared with the randomly selected background combined with a fitness disadvantage of the transgene. Therefore, the utility of a transgene in improving a quantitative trait may depend in part on genetic background. Correlated responses for most traits in NC were similar for Z and C. In contrast, correlated responses in TC showed marked differences in C compared with Z. For example, daily gain and feed efficiency showed no significantly correlated responses under C and positive responses (p < 0.001) under Z, and the reverse was found for indicators of body fat percentage. These line by environment (Z versus C) interactions may represent a genetic correlation of less than one between a trait expressed in two distinct environments. Thus, in developing lines with a transgene that can be regulated, a critical question is whether selection for quantitative trait(s) should be conducted when the transgene is activated or not activated.
Genetic parameters of racing performance traits of Quarter horses in Brazil
Authors: VILLELA L. C. V. , MOTA M. D. S. , OLIVEIRA H. N.
Published: March 2003

The data used in the present study were recorded at the Jockey Club of Sorocaba for 5094 racing performance of 1350 Quarter Horses at the Paulista Race Track of Sorocaba, state of São Paulo, Brazil, from 1991 to 1997. The considered traits were time and final rank. The model used in analysis included random animal and permanent environmental effects, and race, sex, age and origin as fixed effects. The variance and covariance components were estimated by the restricted maximum likelihood for an animal model, using the derivative‐free process method and the MTDFREML software. For the time, heritability was 0.17 (0.05), while estimate of repeatability 0.55 (0.05). The lower heritability for the final rank, 0.13 (0.04), indicate that this trait is not the most appropriate one for inclusion in programs of Quarter horse selection in Sorocaba racetrack. The repeatability estimate for rank was 0.44 (0.04) and the genetic correlation between this trait and time was 0.99.
GENCHECK: A program for consistency checking and derivation of genotypes at co‐dominant and dominant loci
Authors: Bennewitz J. , Reinsch N. , Kalm E.
Published: March 2003

The program GENCHECK was developed to examine genotyping results of diploid organisms for consistency with the Mendelian laws of inheritance. It can be used to analyse data from co‐dominant and dominant loci and large scale pedigrees with many overlapping generations as they are common in animal breeding. The pedigree data and genotyping results are read either from a suitable database or from an ASCII file. The data from individuals, whose genotyping results show a Mendelian segregation error, are written to an output file. Possible error sources can be a result from genotyping errors, false parentage and erroneous data transfer. Additionally, the program derives, if possible, the genotypes of untyped individuals or of individuals, whose genotyping results were assumed to cause a Mendelian segregation error, using information from the parents and/or the offspring. Error checking and derivation of genotypes are combined in a single computation step. Important technical solutions for example, the examination of genotyping results from dominant loci, the representation of possible genotypes on the bit‐level and the dependency of the results on ordering individuals in different ways are discussed. The program is written in Fortran 90 and available from the authors.
Comparative study on the regulation of body fluids and mammary circulation at different stages of lactation in crossbred Holstein cattle feeding on different types of roughage
Authors: Chaiyabutr N. , Preuksagorn S. , Komolvanich S. , Chanpongsang S.
Published: March 2003

The present study was carried out to evaluate the effect of prolonged feeding of urea‐treated rice straw, compared with feeding of hay, on the regulation of body fluids, milk yield and mammary circulation at early lactation (30 days postpartum), mid‐lactation (120 days postpartum) and late lactation (210 days postpartum) in crossbred Holstein Friesians. Sixteen first lactating crossbred Holstein Friesians (HF), consisting of eight animals of two breed types, 87.5%HF and 50%HF, were selected and each breed was randomly allocated into two groups. Each group, consisting of four animals from the same breed, was fed either 5% urea‐treated rice straw or pangola hay (Digitaria decumbens) as the source of roughage in combination with a similar concentrate throughout the experiments. During the course of lactation there were no significant differences in body weight, heart rate, mean arterial blood pressure, plasma osmolality, plasma volume and blood volume among groups of 87.5%HF animals and 50%HF animals fed either hay or urea‐treated rice straw. Water turnover rate, total body water space and total body water as a percentage of body weight of 50%HF animals were significantly higher than those of 87.5%HF animals fed either hay or urea‐treated rice straw. The packed cell volume was significantly higher in all lactating periods of both groups of 50%HF animals in comparison with 87.5%HF animals. The ratio of DM intake to milk production for 87.5%HF animals fed either hay or urea‐treated rice straw was significantly lower than that of 50%HF animals in early lactation. The udder blood flow and milk secretion of 87.5%HF were significantly higher in early lactation and markedly declined when lactation advanced in comparison with those of 50%HF animals fed either hay or urea‐treated rice straw. The ratio of mammary blood flow to milk yield for all groups was in a similar range during early lactation although it significantly increased in mid‐ and late lactation for both groups of 87.5%HF animals. From these results it can be concluded that both 50%HF and 87.5%HF animals feeding on urea‐treated rice straw as a roughage source do not show any undernutritional effects in comparison with those fed with hay during the course of lactation. The physiological response differences between breeds are that 87.5%HF animals, which have a genetic makeup closer to the exotic bos taurus breed and a high milk yield, show a poor adjustment to the tropical environment and poorer lactation persistency in comparison with 50%HF animals.
Influence of the dietary potassium content on transepithelial potassium transport in rat jejunum
Authors: Cermak R. , Evelgünne A. , Scharrer E.
Published: March 2003

In a recent study, we found that the distal rat jejunum is able to secrete K+ under in vitro conditions. The question therefore arises as to whether the small intestine might participate in K+ homeostasis. Consequently, this study examined the influence of the dietary K+ content on transepithelial K+ transport in rat jejunum. Rats were fed two diets differing in K+ content (control diet 4.0 g K+/kg, low K+ diet (LK) 0.27 g K+/kg). After a minimal feeding period of 7 days, distal jejunal sheets were mounted in Ussing chambers and unidirectional 86Rb+ fluxes (as a marker for K+ transport) were measured under short‐circuit conditions. Jejunum obtained from rats fed the control diet showed a net K+ secretion of 200 nmol Rb+/h/cm2. Unidirectional Rb+ fluxes were smaller in distal jejunum from rats fed the LK diet. In these tissues, glucose‐induced short‐circuit current and tissue conductance were also smaller than in controls. However, net Rb+ fluxes were not significantly different in small intestine from K+‐restricted rats compared with jejunum from control animals. Based on the observation that the dietary K+ content does not affect transepithelial net K+ transport, we conclude that transcellular K+ secretion by the small intestine is not involved in K+ homeostasis.
Evaluation of urea infusion to estimate in vivo body composition of Belgian blue double‐muscled bulls
Authors: De Campeneere S , Fiems L. O. , Vanacker J. M. , Boucqué CH. V.
Published: March 2003

Urea infusions were performed on 18 Belgian blue double‐muscled bulls, ranging from 308 to 710kg live weight after a fasting period of 16 h. Urea space (US) was determined from the difference in plasma urea concentration between samples taken before and 12, 18 and 24min after mean infusion time. The day after infusion, the bulls were slaughtered and subsequently the body composition was determined. Kg empty body water and empty body protein were quite accurately predicted by US. The precision of the prediction of kg empty body fat was less accurate. However, due to the large live weight interval and the small compositional variation, the fasted live weight (fLW) was a better parameter to estimate the weight of the body components. Prediction of relative body composition (as a percentage) instead of absolute (in kg) improved the standard error of the predictions. In estimating relative body composition, US has proven to be somewhat better than fLW, but the extra precision from using urea infusion was not large enough to justify the extra work of the infusion. The time for equilibration of the urea in the water compartment was obviously longer in this study than in others, presumably due to the lower capillary density of the Belgian blue double‐muscled animals.
The antinutritive effect of a carboxymethylcellulose with high viscosity on lipid digestibility in broiler chickens is not associated with mucosal damage
Authors: Smits C. H. M. , Te Maarssen C. A. A. , Mouwen J. M. V. M. , Koninkx J. F. J. G. , Beynen A. C.
Published: March 2003

The condition of jejunal and ileal mucosa was examined to study whether the inhibitory effect of fibre viscosity on lipid digestibility in growing chickens is associated with damage to the small intestinal mucosa. Two semi‐purified diets were prepared and fed to growing chickens from 7 to 18 days of age. A nonfermentable carboxymethylcellulose (CMC) with high viscosity was added to one diet Lipid digestibility was depressed in the birds that were fed the diet containing CMC (p = 0.021). The villi were significantly longer in the jejunum of CMC‐fed chickens (p = 0.033) and the number of goblet cells per 100 µm of villus length was raised (p = 0.082). There was no significant effect on the proliferation rate of enterocytes in the jejunum and ileum; neither did the CMC diet significantly affect the composition of mucins in the villi. In contrast to the working hypothesis, the results indicate that CMC may have had a beneficial instead of a detrimental effect on the condition of the small intestinal mucosa. The effect of gelling fibres on the condition of the mucosa may be dependent also on their fermentability. Luminal events must be held responsible for the lowered lipid digestibility in broiler chickens that were fed the diet containing highly viscous CMC.
Apparent digestibility of crude fibre in ponies fed either a low or high‐protein diet
Authors: Rey F. , Hallebeek J. M. , Beynen A. C.
Published: March 2003

The question addressed was whether apparent crude fibre digestibility in ponies would change after lowering protein intake from adequate to borderline deficient. Four adult ponies were fed a low‐ and high‐protein diet according to a cross‐over design. The diets consisted of grass hay and concentrates and provided either 1.5 or 3.6 g digestible crude protein/kg0.75 per day. The two whole rations provided 2.4 g crude fibre/kg body weight per day. Apparent crude fibre digestibility was not affected by protein intake (low‐protein diet: 42.9 ± 4.03%; high‐protein diet: 38.1 ± 1.14%, means ± SE, n=4). The low‐protein diet caused a significant increase in the ratio of faecal: urinary nitrogen. It is suggested that, when the low‐protein diet was fed, sufficient urea flew from the blood into the intestine and ammonia released in the hindgut was conserved so that microbial growth, and thus fibre fermentation, was maintained.
Supplementation of algae to the diet of pigs: a new possibility to improve the iodine content in the meat
Authors: HE M. L. , HOLLWICH W. , RAMBECK W. A.
Published: March 2003

Meat products with a higher iodine content can be produced through feeding animals with a diet supplemented with inorganic iodine salts or with algae containing high iodine. This may help to improve daily iodine intake and to control iodine deficiency disorders (IDD) in man. In the present study a total of 40 crossbred pigs (Deutsche Landrasse × Piétrain) with an average body weight of 17 kg were allotted to either a control group, to two groups receiving potassium iodide (KI) at different concentrations (5 or 8 mg iodine per kg of feed) or to two groups receiving the algae Laminaria digitata containing the same amount of iodine. After pigs were fed with iodine‐supplemented diets for 3 months, it was found that compared to the control group the iodine content increased by up to 45% in fresh muscle, by 213% in adipose tissue, by 124% in the heart, by 207% in the liver and by 127% in the kidneys. There was a significant (p < 0.01) higher concentration of serum thyroxine (T4) and a lower concentration of serum triiodothyronine (T3) in those iodine‐supplemented groups. The iodine content of urine from all iodine‐supplemented groups was also greatly increased. Furthermore, it was shown that the supplementation of algae into feed could increase daily body weight gain by 10% (p > 0.05). It is suggested that the carry‐over of iodine through feeding pigs with an algae‐supplemented feed could be beneficial to both the control of IDD and the improvement of pig production.
Energy metabolism in young pigs as affected by establishment of new groups prior to transport
Authors: HEETKAMP M. J. W. , SCHRAMA J. W. , SCHOUTEN W. G. P. , SWINKELS J. W. G. M.
Published: March 2003

Energy metabolism was studied in 9‐week‐old‐pigs as affected by mixing just before transport. In each of three trials, two groups of 20 pigs (two litters of 10) were randomly assigned to one of two treatments: control and mixing. Each group was housed in one of two climatic chambers with each subgroup in one of two pens. In each trial, the two litters within the mixing treatment were mixed, just before transport, at the start of a 2‐week experimental period. In the control treatment, the social structure of both litters in each trial was not altered. In both treatments, large alterations of energy partitioning from week 1 to week 2, are probably signs of recovering from transportation and/or adaptation to new feeding and housing conditions. Mixing just before transport did not change total energy metabolism but only increased nonactivity‐related heat production by 3.1% for the total experimental period. Most likely, long‐term performance is also not affected negatively by mixing. Animals seem to be able to change energy expenditure on activity when more energy is required for other physiological processes. This symptom of possible reallocation of energy between different vital live processes (e.g. behavior, protein turn‐over) might be one of the first indications of an impaired well‐being.
A mixture of cottonseed meal, soybean meal and animal byproduct mixture as a fish meal substitute: growth and tissue gossypol enantiomer in juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Lee K.‐J. , Dabrowski K. , Blom J. H. , Bai S. C. , Stromberg P. C.
Published: March 2003

Diets incorporating three different sources of extracted cottonseed meal (CM), soybean meal and an animal protein mixture were evaluated for juvenile rainbow trout. Fish averaging 0.96 g were divided into groups of 30; 3 groups per treatment, and each group was fed one of four diets for a 16‐week period. Fish meal (FM) was replaced on a 25% protein basis by each of three different sources of CM from California (CA), Tennessee (TN), and Arkansas (AR), U.S.A. In the three CM‐containing diets another 25% soybean meal protein and 50% animal protein mixture were also incorporated to completely replace FM protein. The results of growth rate and feed utilization showed that FM could be entirely replaced by a mixture of plant proteins (CM and soybean meal) and animal by‐product proteins. Hematocrit levels were significantly lower in the group fed CM‐containing diets than in the control. The findings suggest that CM can be used as a good protein source by the incorporation of at least 15% in diets (25% of fish meal protein replacement), and that the nutritive values of CM in juvenile trout can be different due to their different origin. Significantly higher concentrations of total gossypol were found in faeces of CM‐TN (5.8 ± 0.4 μmol/g) and CM‐AR (5.6 ± 0.6) groups than in that of CM‐CA (3.7 ± 0.4) group. It was documented that gossypol enantiomers, present in an equal proportion in diets, selectively accumulated in liver and bile, whereas equal proportions of (+)‐ and (–)‐enantiomers were found in whole‐body and faeces. Depending on CM source, fish can absorb approximately 35–50% of dietary gossypol, and the majority of the absorbed gossypol seemed to be excreted.
Effect of Zn deficiency and subsequent Zn repletion on bone mineral composition and markers of bone tissue metabolism in 65Zn‐labelled, young‐adult rats
Authors: Windisch W. , Wher U. , Rambeck W. , Erben R.
Published: March 2003

The objective of the present study was to investigate the effect of changing skeletal Zn load (mobilization/restoring) on bone mineral composition and bone tissue metabolism. For this purpose, 36 65Zn‐labelled, young‐adult female rats were fed with either a purified diet with sufficient Zn (21 μg/g, control) for 26 days, or deficient Zn (1.4 μg/g) for 12 days followed by 14 days repletion with the control diet. The animals were killed at the onset of the study (reference: n=4), at the end of the Zn deficiency episode (control: n=4; Zn deficiency: n=4), subgroups (n=4) of Zn repleted animals at repletion days 2, 4, 7, 10 and 14, and at day 14 the remaining controls also (n=4). Zn deficiency reduced skeletal Zn concentration from 198 to 155 μg/g of bone dry matter. About half of mobilized skeletal Zn was refilled within 2 days of repletion and was completely restored until the end of the study. Concentrations of bone ash, Ca, P and Mg remained constant (means in bone dry matter: 51% bone ash, 191 mg Ca/g, 95 mg P/g, 4.4 mg Mg/g). Blood plasma concentrations of osteocalcin and daily urinary excretions of pyridinoline PYD and dexoxypyridinoline DPD were unaffected by treatment (mean: 57 ng/ml, 222 nmol/day, 137 nmol/day). Also daily urinary excretions of Ca, P and Mg remained fairly constant (means: 0.26 mg/day, 16 mg/day, 1.5 mg/day). 65Zn autoradiography of femur sections revealed a pronounced Zn exchange in the area of the metaphysis and epiphysis. We conclude that transient mobilization and restoration of skeletal Zn occurs mainly in trabecular bone, and does not involve major changes in bone mass, macro mineral content, or bone tissue turnover in young‐adult rats.
The estimation of utilizable amino acids (uAA) of feeds for ruminants using an in vitro incubation technique
Authors: Zhao G. Y. , Lebzien P.
Published: March 2003

The in vitro incubation technique of Zhao and Lebzien (2000; Arch. Anim. Nutr. 53, 293–302) was used for the estimation of utilizable amino acids (uAA) (sum of amino acids from undegraded feed protein and microbial protein, when N is not limiting) of feeds for ruminants. The rumen fluid from a cow fed only with hay (Expt. 1) and that from a sheep fed with a mixed ration (Expt. 2) was compared with respect to estimation of uAA. In Expt. 1, 30 feeds and feed mixtures were tested and in Expt. 2, 33 feeds and feed mixtures were tested. A close linear relationship was found between the utilizable crude protein (uCP=undegraded feed protein + microbial protein) (X, g/kg) calculated from in vivo experiments and the uAA (Y, g/kg) estimated from in vitro incubations both in Expt. 1: y= 0.95 x−1.39, r2=0.85, p<0.001,n=30; and in Expt. 2: Y=0.85X−6.67,r2= 0.85,p<0.001,n=33. Statistical analysis indicates that there was a significant regressive relationship between uAA determined with the rumen fluid of a sheep (X, g/kg) and uAA determined with the rumen fluid of a cow (Y, g/kg): Y=1.06X+12.4,r2= 0.80,p<0.001,n=27.

The results indicate that the in vitro incubation technique of zhao and lebzien (2000) can be used for the estimation of uAA of feeds for ruminants. As a rumen‐fistulated cow is more expensive than a rumen‐fistulated sheep, it is suggested to use a sheep fed a mixed ration as the donor of rumen fluid for the estimation of uAA of feeds with in vitro incubation. Further experiments should be performed to standardize the method and to test the most valid length of the incubation period.
Vitamin C concentrations in blood plasma, tissues and urine of camels (Camelus dromedarius) in Sudanese herds
Authors: Mohamed H. E. , Beynen A. C.
Published: March 2003

There is suggestive evidence that a low status of ascorbic acid in ruminants is related with decreased disease resistance. In a first attempt to identify conditions in camels that could affect their health, an inventory was made of ascorbic acid (vitamin C) concentrations in plasma and tissues as related to breed, gender, sexual activity and season. A total of 3429 camels were studied and sub‐samples were used for selected comparisons. The highest concentrations of ascorbic acid were found in adrenals (152 mg/100 g wet tissue) and the lowest in heart (8 mg/100 g), the levels being unrelated with season. Arabi camels had higher plasma concentrations of ascorbic acid (6.42 μg/ml) than did Anafi and Bishari camels, the latter breed showing the lowest concentrations (3.24 μg/ml). Female camels of the Anafi breed had higher concentrations urinary ascorbic acid than did their male counterparts. It is suggested that in camels the main elimination route of vitamin C is with urine. Female and male Arabi camels that were sexually active had 52 and 23% lower plasma ascorbic acid concentrations than did their sexually inactive counterparts. It is suggested that especially Bishari camels during the breeding season might be sensitive to disease.