单播草坪匍匐翦股颖溶磷菌筛选及溶磷能力的初步研究

对西安地区单播草坪匍匐翦股颖根际联合固氮菌进行分离的基础上,采用PKO无机磷培养基和蒙金娜有机 培养基对匍匐翦股颖根际分离的联合固氮菌(共获得188种分离物)中具有溶磷能力的菌株(占29.3％),通过对菌株溶 磷圈大小的测定,最终筛选出溶磷能力较强菌株4株,分离物溶解无机磷D/d值在1.324~3.014之间;而溶解有机磷的能力 在1.239~2.156之间。     

Experimental studies of anemia in cattle caused by immune antibody. 2. Behavior of plasma hemoglobin, and serum bilirubin, inorganic phosphorus and calcium

The course of haemolytic anaemia, caused by immune antibody, was characterised in greater detail with reference to eight heads of young cattle examined for plasma haemoglobin, bilirubin, inorganic phosphorus, and calcium in serum. Inorganic serum phosphorous values were found to decline strongly immediately after the onset of iso-immune serum transmission. Severe haemolysis developed, but only moderate haemoglobinaemia and no haemoglobinuria at all occurred. Bilirubin was increased over a long time, which seemed to support the assumption of gradual erythrocyte decomposition. The usefulness of inorganic serum phosphorus determination as an approach in support of early diagnosis of aggravating haemolysis is confirmed and recommended for metabolic monitoring of cattle herds.     

体外法研究不同磷添加水平对奶牛瘤胃内pH 和挥发性脂肪酸的影响

采用体外法研究无机磷添加浓度对瘤胃发酵的影响。无机磷在培养液中设0、30、60、90、120、150、200、250、300、350 mg/L 10个水平。体外培养发酵48 h后终止培养,测定培养液的pH、总挥发性脂肪酸(VFA)。结果表明,不同无机磷添加水平对乙酸、丙酸、丁酸和总VFA产量影响显著(P＜0.05),无机磷添加水平为200 mg/L时,乙酸、丙酸、丁酸及总VFA产量最高,随后下降。瘤胃培养液pH随无机磷添加水平的增加而显著降低(P＜0.05),无机磷添加水平为200 mg/L时达到最小值5.65,随后又上升。在本试验条件下,添加无机磷明显促进瘤胃微生物对饲料养分的发酵,适宜添加水平为200 mg/L。     

Effects of heparin, citrate, and EDTA on plasma biochemistry of sheep: Comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals, but limited information is existing for sheep plasma biochemistry. Ten clinically healthy Baloochi breed of sheep were blood sampled in different tubes containing each anticoagulants and plain tube for harvesting plasma and serum. The concentrations of glucose, cholesterol, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, and magnesium and the activity of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of GGT, bilirubin and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than that of serum. For corrected citrated plasma significant differences were seen for the concentrations of glucose, creatinine, calcium and the activity of ALP.Most parameters did not show any difference, but significant increase was seen for albumin concentration when heparin was used as an anticoagulant. Using EDTA as anticoagulant caused a significant difference for the concentrations of some of the measured parameters in plasma except glucose, GGT, cholesterol, albumin, bilirubin, CK, and inorganic phosphorus comparing with serum.     

Study of ECG in lactating cows. 2nd communication: ECG compared to behavior of various parameters of mineral and carbohydrate-fat metabolism

Metabolism checks were carried out on eight dairy cow stocks, with 155 high-performance cows in first lactation being electrocardiographically and biochemically tested. Determined with the blood-borne concentrations of glucose, ketone body, calcium, magnesium, and inorganic phosphorus. The electrocardiographic recording were compared with behaviours of the blood parameters, and PQ conduction was found to be shortened in hypoglycaemic animals. Changes in calcium and magnesium serum concentrations were found to produce tbe most unambiguous effects on a number of ECG components, and reciprocal influence of these two components was as well observed. No correlation with ECG were recordable from the other parameters.     

土地利用方式对陇中黄土高原土壤磷组分的影响

对陇中黄土高原地区至少已有50年传统耕作历史的农田(耕作和休闲)和退耕24年的草地(围封和放牧)土壤磷组分进行了比较研究。结果表明,1)农田土壤中活性无机磷(H₂O-Pi、NaHCO₃-Pi)、潜在活性无机磷(NaOH-Pi)和0～10 cm土层中稳性无机磷(DHCl-Pi)以及30～60 cm土层高稳性无机磷(HHCl-Pi)的含量显著高于草地;潜在活性有机磷(NaOH-Po)含量0～10 cm土层围封草地显著高于农田,20～60 cm土层农田显著高于草地。2)土壤各磷组分之间的迁移转化主要发生在中稳性无机磷DHCl-Pi与其他磷组分之间,且农田中磷组分之间的转化主要发生在0～20 cm土层。3)土壤速效磷、全磷与H₂O-Pi、NaHCO₃-Pi、NaOH-Pi之间及土壤全氮、有机碳与NaOH-Pi、NaOH-Po、HHCl-Pi之间呈极显著正相关关系,而土壤pH与NaHCO₃-Po呈显著负相关,与H₂O-Pi、NaHCO₃-Pi、NaOH-Pi、NaOH-Po、HHCl-Pi极显著负相关。     

体外法研究不同磷添加水平对奶牛瘤胃发酵的影响

本试验采用体外法研究无机磷对瘤胃发酵的影响。无机磷在培养液中设0、30、60、90、120、150、200、250、300、350 mg/L 10个水平。体外培养发酵48 h终止培养,测定培养液的产气量和干物质降解率。结果表明:无机磷添加水平对48 h总产气量和干物质降解率影响显著(P<0.05),随着无机磷添加水平的提高,48 h总产气量和干物质降解率显著提高(P<0.05),添加水平为200 mg/L时达到最大值,分别为44.30 mL和54.80%,随后下降。在本试验条件下,无机磷的适宜添加水平为200 mg/L。     

Evaluation of a Microbial Phytase,Produced by Solid-State Fermentation,in Broiler Diets. 1. Influence on Performance,Toe Ash Contents,and Phosphorus Equivalency Estimates

The influence of graded additions of a microbial phytase, produced by solid-state fermentation, on the performance and toe ash contents of male and female broilers fed a wheat-soy-canola diet was investigated in a 42-d trial. Responses to graded levels of inorganic phosphorus were also evaluated to calculate the equivalency values of the phytase for inorganic phosphorus. Weight gains, feed per gain, and toe ash contents were increased as the inorganic phosphorus or phytase was added to the low-phosphorus diet. The magnitude of increment in these parameters was greatest for the first addition of inorganic phosphorus or phytase and then tended to plateau with further additions. Weight gain and toe ash content of birds fed the low-P diet with 500 phytase units (PU)/kg of diet were similar to those of birds fed the adequate-P diet, but the feed efficiency was 1.6 to 3.3% better. In general, the treatment effects on parameters tested were similar in both sexes. Spurious phosphorus equivalency values, translating into phosphorus release values of 72 to 137% from phytate-phosphorus, were obtained for this phytase product. These findings highlight the limitations of employing conventional methods to determine equivalency values for a microbial phytase product that contains side-enzyme activities.     

Effects of Common Anticoagulants on Routine Plasma Biochemistry of Horse and Comparison with Serum

The effects of various types of anticoagulants on plasma biochemistry have been studied in humans and various animals; however, limited information exists for effects on horse plasma biochemistry. Ten clinically healthy Thoroughbred horses were blood sampled in tubes containing different anticoagulants as well as no anticoagulant. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, blood urea nitrogen (BUN), creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium and iron, and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), and gamma glutamyl transferase (GGT) were measured. Except for the amounts of inorganic phosphorus, magnesium, and GGT, other measured parameters were significantly lower in citrated plasma than in serum. When corrected for dilution, significant differences were seen for the amounts of glucose, cholesterol, triglyceride, bilirubin, calcium, iron, and the activity of ALT, ALP, and CK in citrated plasma. Most parameters did not show any difference; however, significant decreases in BUN, total bilirubin, ALT, and CK activity were seen when heparin was used as an anticoagulant. When compared with serum, using ethylenediaminetetra-acetic acid (EDTA) as an anticoagulant produced a significant difference in the amounts of measured plasma parameters with the exception of GGT, albumin, creatinine, inorganic phosphorus, and triglyceride.     

A comparative study on the chemical composition of plasma from the cauda epididymidis, semen fractions, and whole semen in boars

A comparative study was carried out on the chemical composition of plasma from the cauda epididymidis, semen fractions, and whole semen of boars. A total of 22 boars were used in this study. The boars, which ranged in age from 8 to 14 months, were of Swedish Landrace and Swedish Yorkshire breed. All boars used presented a normal semen picture. A dummy sow and an artificial vagina were employed for semen collection. The semen was collected as whole semen and as semen fractions in 10 nil volumes. The contents of the cauda epididymidis was removed post mortem.The following parameters were investigated: sperm concentration, dry weight of spermatozoa and of seminal plasma, osmotic pressure, sodium, potassium, chloride, inorganic phosphorus, calcium, magnesium, total protein, GOT, GPT, and alkaline phosphatase in seminal plasma. Paper electrophoresis was carried out on seminal plasma. Tlxe results of the analysis are summarized in Tables 1–6.The sperm concentration was approximately 3.2 mill./mm3 in the cauda epididymidis, 1 mill./mm³ in the sperm-richest fraction (II) and 0.25 mill./mm3 in whole semen. The dry weight (expressed in per cent dry matter) of spermatozoa was highest in the cauda epididymidis (25.47 %), showing a tendency to decreasing in semen fractions I—IV and was lowest in whole semen (15.29 %). The per cent dry weight in plasma was higher in the cauda epididymidis (4.56 %) than in semen fraction I (2.20 %). In semen fractions I—IV the per cent dry weight rose from 2.20 (U to 4.51 % and reached the level of approximately 3.80 % in the sperm-free fractions V—VII. The osmotic pressure was significantly higher in the cauda epidi-dymal plasma than in the whole seminal plasma or the seminal plasma fractions. The same phenomenon was observed in a boar where the cauda epididymal content was collected in vivo from a patent established fistula. There appears to be a connection between the per cent dry weight of spermatozoa and the osmotic pressure, which means that the per cent dry weight of the cauda epididymal spermatozoa decreases when mixed with the accessory gland secretions, which have a lower osmotic pressure. The fall in per cent dry weights is thought to be caused by an intake of water.The amount of sodium, chloride and magnesium was higher in ejaculated seminal plasma than in cauda epididymal plasma. The reverse was true for inorganic phosphorus and potassium. Moreover the sperm-free fractions contained more sodium, chlorides and magnesium than the sperm-containing fractions, while the concentration of potassium and inorganic phosphorus was comparatively higher in the sperm-containing fractions. A connection is apparent between sperm concentration and the potassium, inorganic phosphorus and magnesium levels. Statistical analysis of the values of chloride and magnesium revealed significant differences between individual boars for most of the semen fractions.The concentration of plasma proteins in the cauda epididymidis was approximately the same as in whole semen and in the semen fractions except for fraction I, which contained a relatively low concentration. As regards total protein there were significant differences between individual boars in most of the semen fractions as well.The paper electrophoretic pattern of epididymal plasma was different from that of semen plasma. Thus there were three or four distinct components in the cauda epididymidis numbered 1, 2, 3, and 4, and three distinct components in whole seminal plasma numbered 3, 4, and 5, while the sperm-richest semen fractions contained four components (2, 3, 4, and 5) and the others three components, namely 3, 4, and 5.The level of GOT was high in the cautlu cpiflidymill contents (99.1 i. u./ml) compared with that for whole seminal plasma (99.1 i.u/ml). In semen fractions there was a clear positive correlation between the level of GOT and the sperm concentration. The GPT concentration wis as a whole low and. in contrast to GOT. somewhat higher in the sperm-free fractions than in the sperm-containing fractions. The concentration of alkaline phosphatase was very high in cauda epididymal plasma (31,463 i. u./ml) as well as in the sperm-rich fractions (e.g. 7,096 i. u./ml in fraction II). Preliminary investigation has moreover revealed a very low alkaline phosphatase concentration in seminal plasma of vasectomized boars, which condition suggests thai the main origin for alkaline phosphatase in boars is the testis and epididymis.     

磷酸一二钙在产蛋鸡配合饲料中的应用研究

选择210日龄伊莎产蛋高峰期鸡1 755只,随机分为1个对照组和12个试验组.12个试验组分别饲喂对照组日粮基础上(0.14%非植酸磷)添加不同水平(0.06%、0.12%和0.18%非植酸磷)无机磷源(磷酸二氢钾(MPP)、磷酸二氢钙(MCP)、磷酸氢钙(DCP)、磷酸一二钙(MDCP))的日粮.通过测定相对生物学效价(RBV),比较4种无机磷对产蛋鸡生产性能的影响.试验结果表明:在不同磷添加水平下MPP、MCP、DCP、TCP的RBV值,以产蛋率为指标,各组分别为100、101、107和110;以平均蛋重为指标,各组RBV值分别为100、106、124和126;以平均日产蛋量为指标,各组RBV值分别为100、103、114和116.综合各指标的平均生物学效价,各组分别为100、103、115和117.表明以磷酸一二钙作为蛋鸡日粮的无机磷源利用效率最佳,磷酸氢钙是蛋鸡日粮较好的磷源.     

Bovine post-parturient haemoglobinuria: two distinct entities in New Zealand

Haematological and biochemical features of sixteen cases of post-parturient haemoglobinuria (PPH) from 15 farms in the Waikato and Bay of Plenty regions are described. Characteristically there was a marked regenerative anaemia as well as spherocytosis and haemoglobinaemia. Heinz body formation occurred in 140% of erythrocytes depending on the case. Nine of 11 cases examined had subnormal serum inorganic phosphorus concentrations. On two of eight farms there was widespread anaemia in clinically healthy herd mates and in one of these the anaemia was associated with large numbers of Heinz bodies. Hypophosphataemia was widespread in four of ten herds and individual cows were hypophosphataemic in all ten. Six of eight herds had a low selenium status as determined by glutathione peroxidase activity in whole blood. Hypocupraemia and hypomagnesaemia were not consistent findings. It is concluded that there are two distinct entities of PPH in the region. On one farm the disease was typical of that seen in Northland, New Zealand. The clinical case was a young cow and there was widespread subclinical Heinz body anaemia in herd mates. All but one of the cows sampled in that herd had normal serum inorganic phosphorus levels. On most other farms PPH closely resembled that described from North America. Affected cases were miltiparous, high producing and had low serum inorganic phosphorus levels. The possible pathogenesis of these two entities is discussed.     

Patterns and relationships of plasma calcium, protein and phosphorus during the egg laying cycle of the fowl and the effect of dietary calcium

In 29 domestic hens, four blood samples were collected during the period of egg formation, at time points representing different metabolic stages. Plasma concentrations of total calcium, total phosphorus, inorganic phosphorus and total protein were measured, and the effect of adding oyster shell particles to a standard laying diet was investigated. Analyses of covariance were made and correlations between the plasma characteristics were calculated. The following were significantly correlated: total and inorganic phosphorus, calcium and total phosphorus, and calcium and protein. Each of the four characteristics showed a significant decrease during egg formation. Inorganic phosphorus reached a peak 15 h after ovulation, probably related to medullary bone resorption. Plasma total phosphorus differed significantly between chickens. Addition of oyster shell to the diet did not affect the concentration or the pattern of the plasma characteristics during egg formation and did not reduce calcium mobilisation from medullary bone during shell formation.     

长期定位施肥条件下紫色土无机磷形态演变研究

应用蒋柏藩-顾益初无机磷分级体系对22年长期定位施肥试验紫色土0~100 cm土层无机磷形态进行分级测定,研究了各形态的无机磷在土壤剖面的分布及演变规律。结果表明,长期施用化学磷肥以及有机无机肥配施处理的土壤全磷、有效磷和各形态无机磷均较试验前有不同程度的增加,且以猪粪+NPK(M+NPK)处理土壤增加最多,其中有效磷含量增加了6倍;不施肥(CK)和单施氮肥(N)的处理土壤有效磷、全磷和各形态无机磷出现了下降,其中有效磷含量分别降低了51.1%和53.5%。除了Fe-P 和Ca₁₀-P含量下层高于上层外其余各形态无机磷都表现为耕层高于下层的特征。各处理Ca₂-P、Al-P、Ca₈-P、O-P等无机磷的剖面分布较为相似,均呈20~60 cm下降比较迅速,80~100 cm变化不大或者稍微上升的趋势,而Fe-P则表现为下层含量高于耕层。相关分析表明各组分无机磷对紫色土有效磷的贡献为Ca₂-P(0.9569)>Al-P(0.9265)>Ca₈-P(0.9100)>Fe-P(0.8277)>Ca₁₀-P(0.7449)>O-P(0.7362)。长期有机无机肥配施可以显著增加磷素在土壤中的累积,并能减少土壤对磷素的固定,增强其在土壤中的移动,促进土壤磷素向有效态转化。     

The influence of mineral supplementation on skeleton formation and growth in Lusitano foals

Diets traditionally used in the horse industry are very often imbalanced in mineral composition, mainly in what concerns Ca, P, Mg and Ca/P ratio. The main objective of this study was to evaluate the effect of calcium, phosphorus and magnesium supplementation of traditional diets, on bone formation and growth in Lusitano breed foals, from weaning to 1 year old. Two homogenous groups of eight colts each received for 140-day iso-energetic and iso-proteic diets, which differed only on Ca, P and Mg levels (respectively, 0.26%, 0.27% and 0.12% vs. 0.56%, 0.43% and 0.18%). Throughout the experiment, blood samples were periodically collected for evaluation of total calcium, inorganic phosphorus, magnesium, copper, zinc, intact parathyroid hormone, bone alkaline phosphatase and osteocalcin concentrations. Animals were weighed and measured (wither height, hip height, girth and cannon circumference) for body growth evaluation. No significant differences were observed between treatments, with respect to growth, plasmatic concentrations of analysed minerals or biochemical markers. The linearity of growth in both groups is in agreement with studies reported for other light breeds. The observed results could be explained by the fact that calcium, phosphorus and magnesium levels in the base diet were close to supply the animal needs for a moderate growth. Further studies concerning the relationship between bone biochemical markers and mineral nutrition, in the growing horse, should consider the evaluation of bone mineral density and content.     

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance, Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to evaluate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1, 150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phosphorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2, 120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemented with 0, 250, 500, or 1,000 FTU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conversion as a result of feeding the different sources of inorganic phosphorus. The digestibility of phosphorus was significantly lower (P = 0.01) for chicks fed diets supplemented with tricalcium phosphate than for chicks fed the other two diets.  However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feed conversion showed a linear improvement (P = 0.03) with increasing levels of phytase inclusion (days 0 to 33).  Phytase supplementation resulted in linear increases in the digestibility of dry matter (P = 0.02), crude protein (P = 0.04) and energy (P < 0.01).  Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium (P = 0.05) and bone breaking strength (P = 0.04) than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets supplemented with dicalcium phosphate, tricalcium phosphate or defluorinated phosphate was similar and therefore production costs could be lowered by choosing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formulated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase supplementation.  However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be sufficient justification for the routine inclusion of phytase in diets fed to broilers.     

农牧交错带人工种草对土壤磷素有效性的影响

在北方农牧交错带,选择种植4年的多年生人工草地,即扁穗冰草、草地雀麦、无芒雀麦、羊草和紫花苜蓿草地,研究了人工种草对土壤磷素有效性的影响。结果表明,人工种草后土壤总有机碳含量接近天然草地水平,而人工草地土壤全磷含量、Ca-P含量显著低于天然草地,且速效磷含量均在3mg/kg以下。人工草地土壤无机磷占全磷的比例显著低于天然草地,且人工草地土壤O-P无法检测出含量(除扁穗冰草草地)。相关分析表明土壤速效磷含量与土壤各形态无机磷均呈显著正相关关系,说明在磷素较低的石灰性土壤中,各形态无机磷都是植物所需磷素的重要来源。     

Treatment of parturient paresis with high-dose calcium

The goal of the present study was to evaluate a calcium dose that was higher than the conventional dose for treatment of parturient paresis in cows. Thirty cows with parturient paresis received 1000 ml of 40 per cent calcium borogluconate solution supplemented with 6 per cent magnesium hypophosphite. Cows in group A received 200 ml of the solution intravenously over a 10-minute period, and the remaining 800 ml via a slow intravenous drip over a six-hour period. Cows in group B received 500 ml of the solution intravenously over a 20-minute period, and the remaining 500 ml via a slow intravenous drip over a six-hour period. Afterwards, the cows were monitored continuously and examined every hour for eight hours. Samples of blood were collected from all the cows before treatment and at 10, 20, 40, 60, 90, 120, 180, 240, 300, 360, 420 and 480 minutes and 24, 48 and 72 hours after treatment. The concentrations of total calcium, ionised calcium, inorganic phosphorus and magnesium were determined. Cows that did not stand within 12 hours of treatment received one or more additional treatments. There was no significant difference in the recovery rate between the two groups. Of the 30 cows, 14 (47 per cent) rised after one treatment and 15 others (50 per cent) were cured after two or more treatments. One cow did not respond to repeated treatments and was euthanased four days after the start of treatment. The results of electrolyte analyses before treatment did not differ significantly between the two groups. In 27 (90 per cent) cows, the concentrations of calcium and inorganic phosphorus were lower than normal and in 3 (10 per cent) cows, only the concentration of inorganic phosphorus was lower than normal.The concentration of total calcium increased markedly ten minutes after the start of treatment in both groups, and at eight hours, the mean concentration of calcium was within the normal range. At 24 and 48 hours, the mean concentration of calcium was below normal, but at 72 hours it was again within the normal range. The concentration of inorganic phosphorus increased slowly in both groups, although it was not within the normal range at eight hours. In both groups, it achieved normal values at 24, 48 and 72 hours.The mean electrolyte concentrations did not differ significantly at any measuring point between cows that stood within eight hours of treatment and those that did not. Our results indicate that increasing the dose of calcium administered does not improve the recovery rate of cows with parturient paresis.     

Effect of dietary phosphorus concentration and electrolyte balance on the growth performance of broiler chickens

The performance of 1680 male and female broiler chickens given diets with either a low (4.7-4.3 g/kg) or high (8.9-8.2 g/kg) content of inorganic phosphorus and four (150, 200, 250 and 300 mEq/kg) electrolyte balances (Na+K-Cl) was measured from 1-d-old to 49 d of age. Diets with the higher concentration of inorganic phosphorus reduced body weight gains in the starter (P less than 0.01) and finisher (P less than 0.05) phases but the efficiency of food utilisation was reduced only in the starter phase (P less than 0.05). The reduction in body weight gain was greater in males than in females. The growth depression caused by the higher concentration of inorganic phosphorus in the finisher diets was partially alleviated by increasing the electrolyte balance to either 250 or 300 mEq/kg diet. The higher concentration of inorganic phosphorus significantly reduced the dressing percentage and increased the abdominal fat pad weight and litter moisture content. Electrolyte balance had no significant effects on efficiency of food utilisation, abdominal fat pad weights or litter moisture content. Neither the dietary concentration of phosphorus nor the electrolyte balance had a significant effect on mortality or ash content of the tibia.     

2种含磷化合物在双旋环棱螺体内生物积累作用的研究

为了分析双旋环棱螺对富磷污染水体生物积累作用的利弊和潜在影响,采用分光光度法,研究了无机磷、杀灭菊酯2种物质在双旋环棱螺内脏团的沉积作用。分别以不同化合物的水样浓度、双旋环棱螺的体重作为2个试验因子,测定不同的含磷化合物对双旋环棱螺的生物积累作用。结果表明,双旋环棱螺对无机P和杀灭菊酯均有一定的沉积作用;其中无机P的沉积与水样浓度呈正相关;杀灭菊酯的沉积与双旋环棱螺的体重呈正相关。