乳铁蛋白（LF）是一种天然的铁结合蛋白。乳铁蛋白肽（Lfcin）是从LF上被胃蛋白酶水解下来的25个氨基酸残基的小肽。本文综述了LF和Lfcin的结构、抗菌功能和基因表达调控的研究进展。

60头约20kg的杜长大三元杂交猪（DurOc×Landrace×YDrkshire）随机分成2个处理组，即对照组和试验组。每个处理有3个重复组，每个重复10头（阉公猪、母猪各半），对照组饲喂不含甜菜碱的饲粮，试验组饲喂含1500mg/kg甜菜碱的饲粮，试验猪结束体重约为65kg。从试验组和对照组中各挑选体重相近的阉公猪、母猪各6头进行屠宰试验。结果表明：饲喂甜菜碱使阉公猪、母猪的日增重分别达10.30%和15.63%、提高瘦肉率3.01%和8.20%，提高母猪的眼肌面积39.21%；而阉公猪、母猪的背膘厚分别降低18.12%和10.83%。血清中激素水平测定结果还显示，甜菜碱可提高阉公猪、母猪的GH含量62.50%和70.97%、IGF-1含量74.33%和44.98%，且未见性别差异。肌肉样品测定结果表明，甜菜碱明显提高了阉公猪背最长肌酸不溶肉碱的含量（41.26%），但对母猪背最长肌酸不溶肉碱的含量未产生显著影响。结果显示：甜菜碱对20～65kg生长猪的增重和胴体组成的影响上存在着性别差异，在降低背膘厚的效果上，阉公猪优于母猪。这说明甜菜碱作为甲基供体，能更有效地促进阉公猪体内肉碱的合成，加强了体脂（猪主要是背脂）的转运和脂肪酸的β-氧化。在促进生长和提高眼肌面积、胴体瘦肉率的效果上，母猪优于阉公猪。

Rare earth elements (REE) have been shown to influence growth performance in animal production, especially in pigs. In the present study, the effect of oral administration of rare earth elements on growing rats was investigated. Pure LaCl3 or an REE mixture containing 38% of LaCl3, 52% of CeCl3, 3% of Pr Cl3 and 7% of chlorides of other REE were used at two different concentrations as supplements to the diets. Fifty male Wistar rats at 4 weeks of age were allotted to five experimental groups: a control group; a La-low group and a La-high group with 75 and 150 mg/kg LaCl3

This study was conducted to evaluate developmental gene expression of lactoferrin and effect of supplementary iron on gene expression of lactoferrin in mice mammary gland using semi-quantitative RT-PCR analysis. In experiment 1, total twelve female ICR ( Institute of Cancer Research ) mice of four groups, each group of three mice at day 1, 9, 17 and 25 of lactation were used to determine effect of different lactating stages on mRNA expression of lactoferrin. In experiment 2, six groups mice (total twenty-four female mice at day 12 after mating) feeding purified diets (without iron or supplement iron) were assigned to two treatments (control and treatment). The feeding experimental period lasted 35 days. During feeding experiment, six mice with three animals each group were chosen at day 1, 9, 17 and 25 of lactation to determine the effect of iron on lactoferrin mRNA expression of mice at different lactating stages. The current results of experiment 1 showed that lactoferrin mRNA had strong expression at day 1 of lactation, and decreased gradually at day 9 and day 17 of lactation and then increased again markedly at day 25 of lactation. These results implicated that the expression of lactoferrin in mammary gland at different lactating stages is consistent with the changes of lactoferrin concentrations in milk. Iron significantly increased lactoferrin mRNA expression at day 1 and day 25 of lactation. Iron also increased lactoferrin gene expression at day 9 and day 17 of lactation, but statistical result was not significant. These findings raised the possibility that iron supplementation may play a role in regulation of lactoferrin levels in vivo.