Histidine maintenance requirement and efficiency of its utilization in young pigs

Abstract

An experiment was conducted in young pigs (initial BW 10.1 kg) to estimate the maintenance requirement for histidine and its efficiency of utilization for protein accretion using a comparative slaughter technique. Three groups of six pigs each were fed a purified diet supplying 0, 14 or 56 mg histidine per kg BW^0.75. Following 21 d of feeding, pigs were killed for whole body compositional analysis. A representative group of six pigs was killed at the beginning of the experiment. Retention of histidine and total N were the main criteria of response. Histidine retention (R² = 0.73) and N retention (R² = 0.78) were linear functions of histidine intake (p < 0.001). Histidine requirement for zero histidine retention was 15.5 mg/kg BW^0.75, whereas histidine required for zero N retention was 4.1 mg/kg BW^0.75. At zero histidine retention, the pigs retained daily 82 mg N/kg BW^0.75, presumably due to the degradation of histidine-rich compounds such as haemoglobin and/or carnosine. The slope of the regression line relating histidine retention to N retention indicated that 105 mg of histidine was deposited per gram of total N which was considerably less than the estimated histidine concentration in body protein (179 mg/g N). Based on the slopes of regression equations for histidine and N retention, marginal efficiency of histidine utilization was calculated to be 0.94 and 1.34, respectively.     

Lysine maintenance requirement and efficiency of its utilisation in young pigs as estimated by comparative slaughter technique

An experiment was carried out on weaner pigs (initial BW 10.8 kg) to estimate the maintenance requirement for lysine (Lys) and its marginal efficiency of utilisation using a comparative slaughter technique. Three groups of six pigs each were fed purified diets for 21 days supplying Lys at 19.5, 78 or 195 mg/kg W^0.75, which corresponded to 50, 200 or 500% of the assumed maintenance requirement. All other essential amino acids were given at 50% excess. At the end of the experiment, pigs were killed for whole-body nitrogen (N) and amino acid analysis. A representative group of six pigs was analysed at the beginning of the experiment. Based on regression equations, relating Lys or N retention to Lys intake, Lys requirement for zero Lys retention was estimated to be 121 mg/kg W^0.75, while Lys requirement corresponding to zero N retention was 41.7 mg/kg W^0.75. At N equilibrium, the pigs lost 65 mg of Lys per kg W^0.75 daily while at zero Lys retention, the daily N retention was 156 mg/kg W^0.75. The marginal efficiency of lysine utilisation was 0.91. It is concluded that zero lysine retention is a better criterion of lysine maintenance requirement than zero N retention.     

Relationship between maintenance energy requirement,mineral salts and efficiency of glucose to ethanol conversion by Zymomonas mobilis

Summary Minimizing the usage of glucose carbon for growth and cell maintenance energy requirement, specific glucose uptake rates, specific ethanol production rates were increased 5-fold. At 0.2 hr^–1 and Y_g = 0.007–0.009, ethanol production rates of 7.99–8.46 g/ltr/hr, Q_p values of 14.85 g/g/hr were obtained. This relationship is discussed in regard to glucose fermentation efficiency.     

Effect of storage and processing of barley on its utilization by pigs and rats

Grain of 16.7% moisture content was stored in exprimental silos by four methods. These were: (1) controlled environment (a sealed container); (2) addition of 1% acid mixture (60 acetic acid: 40 propionic acid); (3) addition of 3.2% sodium hydroxide in a 32% solution to give 21.8% moisture content; and (4) air-dried (82°C) to 13.3% moisture.After 9 months storage, apparent digestibility of dry matter, nitrogen and neutral detergent fibre was measured with pigs, while true protein digestiblity, biological value and net protein utilization were measured with rats.With pigs, there was no treatment effect on dry matter digestibility, but neutral detergent fibre digestibility was reduced in the dried barley. The apparent protein digestibility was markedly depressed to 44.5% for the alkali-treated grain compared with a mean of 65.1% for the other treatments (P < 0.001). In the rat trial, true digestibility of nitrogen and biological value were severely depressed (P < 0.001) by alkali treatment, but differences between the other treatments were relatively small.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition 1st communication: lysine

The study was conducted to evaluate the variability of efficiency of lysine utilisation in different feed proteins for growing pigs including wheat, unprocessed soybean flakes (SF), hydrothermal processed SF, corn gluten meal (CGM), two batches of soybean protein concentrate (SPC-1, SPC-2), different batches of peas (Pisum sativum) and field beans (Vicia faba). Data about efficiency of lysine are important for further conclusions related to lysine requirement in dependence on level of daily protein deposition. In N-balance studies 161 growing barrows (40-65 kg BW) of the genotype [Piétrain x (Duroc x Landrace)] were randomly allotted into 23 experimental treatments (n = 7) with diets in which lysine was the first limiting amino acid. Data from the N-balance trials were used to calculate efficiency of lysine and consequently lysine requirement based on an exponential N-utilisation model. Results from the present studies indicate that efficiency of lysine in different feed proteins varies in a very wide range and this variation greatly affected the calculated lysine requirement. Therefore, the variation in efficiency of lysine should be taken into account in requirement calculations and consequently in diet formulation for pigs. The results of model calculation for the lysine requirement depending on daily protein deposition (130, 145 and 160 g/d) and efficiency of lysine are given for different standards for comparison (g x kg(-0.67) x d(-1), g x d(-1) and percentage of lysine in the diet). The calculated lysine requirement of growing barrows (50 kg BW) corresponding to an average lysine efficiency was 15.5, 18.0 and 21.1 g/d for daily protein deposition of 130, 145 and 160 g, respectively. The results of the model calculation for 145 or 160 g daily protein deposition are in agreement with actual studies and recommendations of NRC (1998) and DLG (2002) for lysine supply.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition. 2nd communication: threonine

This study was conducted to evaluate the variability of the efficiency of threonine in different feed proteins for growing pigs. This information is of importance for actual conclusions about threonine requirement within the exponential N-utilization model (Liebert and Gebhardt, 1986) used in our investigations. Wheat (as basal protein), high-protein soybean meal, low-protein soybean meal, rapeseed meal, field bean (Vicia faba), peas (Pisum sativum), corn gluten meal and soybean protein concentrate were used as protein sources. Fifty-six growing barrows (40-65 kg BW) of the genotype Piétrain x (Duroc x Landrace) were randomly allotted to eight N-balance experiments (n = 7). Diets were formulated with two main ingredients (wheat + one feed protein) with threonine as the first limiting amino acid in the mixture which was partly supplemented with crystalline amino acids. Based on N-balance data, the efficiency of threonine was determined in protein mixtures and individual feed proteins. Threonine requirement was calculated depending on efficiency of threonine and level of daily protein deposition. The results from the present studies indicate that the efficiency of threonine in different feed proteins varied in a wide range. Consequently, this factor has to be taken into account for requirement calculations. The threonine requirement depending on daily protein deposition (130, 145 and 160 g) and the efficiency of threonine according to different reference units (g/BW(kg)(-0.67)/d, g/d and % of threonine in the diet) were calculated. The threonine requirement of growing barrows (50 kg BW) corresponding to an average threonine efficiency was 8.52, 9.92 and 11.61 g/d for a daily protein deposition of 130, 145 and 160 g, respectively. The results for a daily protein deposition of 145 or 160 g are in agreement with actual studies and recommendations for threonine supply.     

Peptide length requirement for experimental allergic encephalomyelitis in guinea pigs

Three peptides overlapping the tryptophan region of bovine CNS myelin basic protein were synthesized by the solid phase procedure of Merrifield. These were the nonapeptide H-Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys-OH, the octapeptide H-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys-OH, and the heptapeptide H-Trp-Gly-Ala-Glu-Gly-Gln-Lys-OH. They were tested for encephalitogenic activity in guinea pigs with either Freund's complete adjuvant containing M. tuberculosis or muramyl dipeptide in incomplete Freund's adjuvant at doses of 10 microgram per animal. The results show that deletion of one or two residues from the amino-terminal end of the nonapeptide destroyed the ability of the shorter peptides to induce clinical but not histological signs of EAE.     

Light utilization efficiency in photosynthetic microbial mats

Based on combined microsensor measurements of irradiance, temperature and O(2) , we compared light energy budgets in photosynthetic microbial mats, with a special focus on the efficiency of light energy conservation by photosynthesis. The euphotic zones in the three studied mats differed in their phototrophic community structure, pigment concentrations and thickness. In all mats, < 1% of the absorbed light energy was conserved via photosynthesis at high incident irradiance, while the rest was dissipated as heat. Under light-limiting conditions, the photosynthetic efficiency reached a maximum, which varied among the studied mats between 4.5% and 16.2% and was significantly lower than the theoretical maximum of 27.7%. The maximum efficiency correlated linearly with the light attenuation coefficient and photopigment concentration in the euphotic zone. Higher photosynthetic efficiency was found in mats with a thinner and more densely populated euphotic zone. Microbial mats exhibit a lower photosynthetic efficiency compared with ecosystems with a more open canopy-like organization of photosynthetic elements, where light propagation is not hindered to the same extent by photosynthetically inactive components; such components contributed about 40-80% to light absorption in the investigated microbial mats, which is in a similar range as in oceanic planktonic systems.     

小麦氮素利用效率的基因型差异

通过土培盆栽试验,研究了130份小麦材料在相同氮素水平下生物量、氮素积累量、氮素生产效率的基因型差异,旨在筛选具有高效利用氮素能力的小麦基因型,为氮高效小麦育种提供种质资源.结果表明:拔节期、抽穗期和成熟期供试小麦单株生物量变幅分别为1.06～3.08 g、1.88～9.05 g和2.64～13.75 g,单株籽粒产量变幅为1.38～9.90 g.拔节期、抽穗期氮素干物质生产效率变幅分别为25.62～65.41 g.g-1 N(F=5.099**)和35.79～88.70 g·g-1 N(F=5.325**),成熟期氮素籽粒生产效率变幅为19.06～38.54 g.g-1 N(F=4.669**).不同氮素生产效率小麦基因型拔节期氮素干物质生产效率(F=637.941**)、抽穗期氮素干物质生产效率(F=201.173**)及成熟期氮素籽粒生产效率(F=443.450**)存在极显著差异.不同氮素生产效率小麦基因型拔节期、抽穗期及成熟期生物量差异显著,有效分蘖数与穗数差异不显著.氮素生产效率高的基因型具有无效分蘖少、抽穗期前氮素利用能力强、抽穗期-成熟期氮素吸收与再利用能力强等特点.典型氮高效基因型小麦省CX...     

Aspects of substrate utilization and energy requirement during molluscan phagocytosis.

When certain ingredients were eliminated from a medium used to culture a cabbage looper cell line that can support replication of Autographa californica nuclear polyhedrosis virus, cells grew successfully and could be serially transferred a minimum of 44 times. Also, they maintained their ability to support replication of the Autographa californica virus, and the polyhedra produced were as infectious as those from cells grown on the original medium. The cost of the least expensive medium that would support cell growth was 2.8 times less than the cost of normal growth medium.     

The maintenance nitrogen requirement of the zebra finch Taeniopygia guttata

A procedure is described for the accurate determination of the maintenance nitrogen requirement (MNR) of small granivorous birds. When used with the zebra finch (Taeniopygia guttata), it yielded a MNR of 403 mg kgW(-0.75) d(-1). This is lower than most other passerines so far measured and more similar to some nonpasserine species. Similarly, the value for endogenous nitrogen loss estimated for the zebra finch (153 mg kgW(-0.75) d(-1)) is less than that for passerines in general but higher than the nonpasserine value. We suggest that the low MNR of the strictly granivorous zebra finch is primarily an adaptation to seed diets in which high-quality protein is a limiting factor. Comparison with a wider range of species reported in the literature was restricted because inappropriate methods have been used to estimate MNR in many cases, including the use of growing or reproducing birds and the assumption that maintenance of body mass necessarily coincides with maintenance of zero nitrogen balance.     

Reaction of young pigs to total gamma-irradiation

A study was made of clinical manifestations of radiation sickness of pigs exposed to gamma-radiation within a wide range of doses, LD50/30 was about 2.82 Gy after a short-term whole-body exposure: the nonuniformity coefficient was 1.2.     

Histidine aminotransferase activity in Streptomyces tendae and its correlation with nikkomycin production

Streptomyces tendae Tü901 produces nikkomycins belonging to the nucleoside peptide antibiotics. Mutants defective in histidine catabolism were isolated and characterized with regard to their histidine ammonium-lyase activity and antibiotic synthesis. In the histidine ammonialyase-negative mutant hut-11 which was unimpaired in nikkomycin production histidine aminotransferase activity was detected as an additional histidine metabolizing enzyme. A protein exhibiting histidine aminotransferase activity could be demonstrated on non-denaturing gels of hut-11 crude extracts. Using optimized assay conditions, histidine aminotransferase activity was investigated in the strain hut-11 during growth in nikkomycin production medium. Maximal activity was reached at the end of exponential growth prior to nikkomycin production. In the presence of bromopyruvate, an effective inhibitor of histidine aminotransferase activity in vitro, production of nikkomycin Z and X was markedly reduced in hut-11.     

Energy requirements of fat sand rats (Psammomys obesus) and their efficiency of utilization of the saltbush Atriplex halimus for maintenance

The fat sand rat (Psammomys obesus; Gerbillinae), a diurnal gerbillid rodent, is herbivorous and able to thrive while consuming only the saltbush Atriplex halimus (Chenopodiaceae), a plant relatively low in energy content and high in ash and water. We measured the basal metabolic rate offat sand rats, their energy requirements in captivity when they were offered only A. halimus, and their efficiency of utilization of this diet for maintenance.
Before consuming A. halimus leaves, the fat sand rats scraped off the surface layers with their teeth. This behavioural activity removed 6.4% to 8.5% of the dry matter of the leaf, but increased the gross energy and organic matter content of the leaf by only approximately 3.1%. Basal metabolic rate of the fat sand rats was 167.9 kJ.kg-O 7s d-', approximately 57% of that expected for an eutherian mammal of its body mass, and energy requirements for maintenance, or average daily metabolic rate, were 498.7 kJ.kg-0'7s d-', approximately 90% of that expected for a rodent of its body mass. Dry matter digestibility of the consumed A. halimus averaged 67% and apparent digestible energy and apparent metabolizable energy averaged 65.3% and 63.4% of the gross energy, respectively. The efficiency of utilization of A . halimus for maintenance energy (k,) by the fat sand rats was 0.32 and the heat increment of feeding (HIF) was 0.68. The k, of A. halimus appeared to be low compared to other feeds, and this characteristic plus its low energy value and high water content forced the fat sand rats to consume large quantities of forage for maintenance.
It was concluded that although A. halimus has a low energy and high ash content, there are several advantages for fat sand rats consuming mainly this diet. Among them are: (1) it provides a more stable diet throughout the year than do seeds; (2) fat sand rats have no competition for this food resource from other rodents; and (3) their burrows are at the base of the