Feeding 5-hydroxy-l-tryptophan during the transition from pregnancy to lactation increases calcium mobilization from bone in rats

An increasing demand for calcium during pregnancy and lactation can result in both clinical and subclinical hypocalcemia during the early lactation period in several mammalian species, in particular the dairy cow. Serotonin (5-HT) was recently identified as a regulator of lactation and bone turnover. The purpose of this study was to determine whether supplementation of the maternal diet with a 5-HT precursor would increase maternal bone turnover and calcium mobilization to maintain appropriate circulating maternal concentrations of ionized calcium during lactation. Female Sprague-Dawley rats (n = 30) were fed either a control diet (n = 15) or a diet supplemented with the 5-HT precursor 5-hydroxytryptophan (5-HTP, 0.2%; n = 15) from day 13 of pregnancy through day 9 of lactation. Maternal serum and plasma (day 1 and day 9 of lactation), milk and pup weight (daily), mammary gland and bone tissue (day 9 of lactation) were collected for analysis. The 5-HTP diet elevated circulating maternal concentrations of 5-HT on day 1 and day 9 of lactation and parathyroid hormone related-protein (PTHrP) on day 9 of lactation (P < 0.033). In addition, 5-HTP supplementation increased total serum calcium concentrations on day 1 of lactation and total milk calcium concentration on day 9 of lactation (P < 0.032). Supplemental 5-HTP did not alter milk yield, maternal body weight, mammary gland structure, or pup litter weights (P > 0.05). Supplemental 5-HTP also resulted in increased concentrations of mammary 5-HT and PTHrP, as well as increased mRNA expression of rate-limiting enzyme in 5-HT synthesis, tryptophan hydroxylase 1, and Pthrp mRNA on day 9 of lactation (P < 0.028). In addition, supplementation of 5-HTP resulted in increased mRNA expression of maternal mammary calcium transporters and resorption of bone in the femur, indicated by increase osteoclast number and diameter as well as mRNA expression of classical markers of bone resorption on day 9 of lactation (P < 0.048). These results show that increasing 5-HT biosynthesis during the transition from pregnancy to lactation could be a potential therapeutic target to explore for prevention of subclinical and clinical hypocalcemia.     

Experimental studies on the impact of an increased dose of anionic salts on the metabolism of dairy cows

Summary

This study was initiated to investigate the influence of a daily dose of anionic salts (AS) above the valid upper limit at present on metabolism of dairy cows. Eleven non‐pregnant and non‐lactating Holstein‐Friesian crossbred cows with a permanent rumen cannula were used in a study with a controlled feeding design. The initial daily dose was 2500 meq/day, which resulted in a Dietary Cation Anion Difference (DCAD) of ‐211 meq/kg dry matter. Every seven days, the daily dose was raised by 500 meq. If a cow stopped eating, the application of AS was stopped and these cows were monitored over the next seven days. On day 30 another batch of hay, having the same DCAD but higher concentrations of minerals and energy, was fed. Blood and urine samples were taken to monitor acid‐base balance and calcium concentrations. Acid‐base balance was strongly influenced by AS. Blood pH dropped steadily and reached values around 7.23. Urine pH dropped quickly below 6 and remained at that level regardless of the increased dosage of AS. Net acid base excretion (NABE) fell continuously with the increase of the dosage of AS and reached values below ‐200 mmol/l. Calcium concentrations in the serum were nearly stable, but those in urine increased sharply and remained on an elevated level with increasing doses of AS. A few days before the individual cow's refusal of feed intake, calcium excretion in urine decreased. The majority of cows stopped eating while consuming a diet containing 3500 to 4000 meq AS except two animals who consumed up to 6000 meq/day AS but they received the better hay in the second half of the treatment period. In this time pH in blood increased slowly. NABE remained stable on a low level at ‐100 mmol/l. The results showed that with an increasing amount of AS fed the risk of clinical acidosis increased. The decreasing urine concentrations of calcium indicate a breakdown of the compensation capability of the single cow. Besides the dose of AS fed, the quality of the feed stuff might be another factor concerning the tolerance of cows against AS.     

不同水钙磷浓度条件下草鱼对水和饲料中钙磷的吸收利用

本研究结果表明:草鱼对饲料钙磷的消化吸收受水中钙磷浓度的影响。草鱼能直接从水中吸收利用钙磷。鱼体存积的大部分来自于水,而磷则大部分从饲料中获得,草鱼钙磷的利用按Ca/P≈1.6的比值进行。     

Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)₂ in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH₃-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.     

Alcohol diluent provides the optimal formulation for calcium chloride non-surgical sterilization in dogs

Background

Surgical castration is widely used to sterilize male dogs, but has significant impacts on time to perform the operation, recovery of the animals as well as cost, which can limit population control programs. Previous research has shown intratesticular injection of calcium chloride dihydrate (CaCl₂) in saline to be a promising alternative to surgery. However, long-term azoospermia was not maintained at dosages low enough to avoid side effects. In the search for an optimized formulation, the current investigation is the first study on long-term sterilization effects of intratesticular injection of CaCl₂ in either lidocaine solution or alcohol in dogs. CaCl₂ at 20% concentration in lidocaine solution or alcohol was administered via intratesticular injection to groups of 21 dogs each. The treated animals were examined at 2, 6, and 12 months for sperm production, blood levels of testosterone, and side effects; at time zero and 12 months for testicular size and semen volume. The experimentally treated animals were compared to a control group receiving saline injection only.

Results

Testicles of dogs treated with CaCl₂ in either diluent significantly decreased in size. After administration of CaCl₂ in lidocaine solution, sterility was achieved for at least 12 months in 75% of treated dogs. However, optimal long-term contraceptive effectiveness was achieved with CaCl₂ in alcohol, which resulted in azoospermia over the 12-month study period. Testosterone levels significantly decreased following treatment with CaCl₂, and sexual activity disappeared. Although testosterone returned to baseline levels by 12 months for the group treated with CaCl₂ in lidocaine, dogs injected with CaCl₂ in alcohol had a 63.6% drop in testosterone level, which remained at the low end of physiological range throughout the study. No adverse effects were noted.

Conclusions

A single, bilateral intratesticular injection of 20% CaCl₂ in 95% ethanol was a reliable method for induction of sterilization in 18–28 kg male dogs in this study. The approach showed long-term efficacy and reduced sexual behavior. This chemical method of sterilization might provide an effective, efficient alternative to surgical castration that can have positive impacts on dog welfare.     

在双低菜籽饼型日粮中添加植酸酶对肉鸡钙磷利用率的影响

在含10%双低菜籽饼的肉鸡日粮中添加600u/kg和700u/kg的植酸酶并取代一半的磷酸氢钙,观察植酸酶对肉鸡钙、磷利用率的影响。结果表明:添加600u/kg和700u/kg植酸酶的试2、3组较未添加植酸酶的试1组其钙和磷利用率分别提高7.08个百分点、9.85个百分点和10.97个百分点、12.13个百分点,植酸磷的利用率提高13.35个百分点、14.01个百分点,磷的排泄量下降10.90个百分点、13.30个百分点,差异显著(P<0.05)。证明在双低菜籽饼型日粮中添加植酸酶改进了钙、磷的利用率,而且还可取代一半的磷酸氢钙。     

京都奶牛场蹄病研究报告

将患有蹄病的奶牛按病情严重程度分为三级,每级选12头,将36头牛随机分为4组,每组9头。第一组为对照组,第二组每头牛日粮中添加35%石粉18g,第三组每头牛日粮中添加硫酸锌1.2g,第四组每头牛日粮中同时添加35%石粉18g和硫酸锌1.2g。同样护理,每周对试验牛群进行修蹄或换药。经过一个月的治疗,第一组治愈1头、有效3头、无效5头;第二组治愈2头、有效6头、无效1头;第三组治愈3头、有效4头、无效2头;第四组治愈7头、有效2头、无效0头。经卡方检验,除第二、三组差异不显著外,其他各组之间差异显著。结果表明,在日粮中适量提高钙、锌含量,对奶牛蹄病有良好的预防和治疗作用。     

饲喂不同日粮的山羊尿沉渣晶体的化学组成和显微形态

采集饲喂棉饼、玉米粉、麸皮、豆饼四种常见日粮的山羊尿样，应用化学定性分析、Ｘ－射线衍射物相分析、Ｘ－射线能谱分析和扫描电子显微镜观察等手段分别进行尿沉渣晶体的化学组成和显微形态的分析和观察。结果表明，饲喂棉饼日粮和麸皮日粮时山羊尿沉渣晶体的化学组成为磷酸钾镁，显微开矿为斜方柱状；饲喂玉米日粮时为碳酸镁，形态为长方柱状；饲喂豆饼日粮时为碳酸钙（方解石），形态为短方柱状。最后，还对几种尿沉渣晶体的生成     

钙锌对蛋用型鸡育成期体组织中矿物元素含量的影响

试验研究了在玉米—豆饼型基础饲粮中添加不同水平锌和钙对蛋用型鸡育成期体组织中矿物元素含量的影响。结果表明,随着饲粮锌水平的提高,肝脏(P<0.01)、肾脏(P<0.05)、胰脏(P<0.01)中锌含量显著升高,而肺脏中锌含量没有显著变化(P>0.05)。饲粮高钙对组织中锌含量的影响未达到显著水平(P>0.05)。饲粮高锌使肝脏磷含量(P<0.05)、肾脏磷(P<0.01)和铜含量(P<0.05)、肺脏钙(P<0.01)和镁含量(P<0.01)显著降低。饲粮商钙使胰脏铜含量(P<0.05)显著提高,使胰脏锰含量显著降低(P<0.05)。     

β-激动剂对鸭Ca、Mn、Zn代谢的影响

用芬茗和克仑特罗饲喂肉鸭２１ｄ,二者对鸭生产性能的影响基本一致。此时,鸭血清碱性磷酸酶（ＡＫＰ）活性和肌浆Ｃａ含量明显增高,而血清和肌浆Ｍｎ含量明显减少。在相同日粮条件下,芬茗处理鸭肌浆Ｃａ、Ｍｎ、Ｚｎ含量均高于克仑特罗处理者（Ｃａ、Ｍｎ达到Ｐ＜０．０５）。克仑特罗处理后引起鸭体内Ｍｎ、Ｚｎ元素丢失增加,这可能是畜禽的后肢乏力、跛行和蹄裂的原因之一。