无氮日粮纤维水平对猪内源氨基酸测值的影响

以醋酸纤维素为纤维源配制成粗纤维水平分别为２．０％、５．０％、８．０％的３种无氮日粮,采用３头回—直肠吻合猪,分３期试验,通过３×３拉丁方设计研究在等进食量（７５０ｇ／ｄ）条件下日粮的纤维水平对回—直肠吻合猪消化道内源氨基酸测值的影响。结果表明：除缬氨酸、异亮氨酸和胱氨酸外,无氮日粮的粗纤维水平对回肠末端食糜干物质中其他内源氨基酸含量（％）无显著影响（Ｐ＞０．０５）。而对回肠末端内源氨基酸的总排泄量影响显著（Ｐ＜０．０５）或极显著（Ｐ＜０．０１）。相关分析表明,粗纤维水平与各种内源氨基酸的排泄总量之间存在显著（Ｐ＜０．０５）或极显著（Ｐ＜０．０１）的强相关关系,随无氮日粮中粗纤维水平的升高,各种内源氨基酸排泄量呈直线增加。     

不同氧化方法对羽毛粉中胱氨酸生成磺基丙氨酸效果的影响

采用均匀设计方法研究了过甲酸法、过乙酸法氧化羽毛粉中胱氨酸为磺基丙氨酸的效果，结果表明，两种方法的效果无显著差异（Ｐ＞０．０５）。从实用经济角度来考虑，以使用过乙酸氧化法为宜。使用此法的最适条件为：过乙酸用量（Ｘ１）０．１ｍＬ／ｇ羽毛粉，过乙酸组成（Ｘ２）（过氧化氢∶乙酸）１∶８；过乙酸的浓度（Ｘ３）９０％；氧化温度１１０℃（Ｘ４）；氧化时间（Ｘ５）８ｈ。在此条件下，磺基丙氨酸最佳得率为８．０２％。氧化条件（Ｘ）与生成磺基丙氨酸（Ｙ）之间的回归方程：ｙ＝０．９４２２＋０．０６８６Ｘ１＋０．５７８７Ｘ２＋０．００４９Ｘ３＋０．００５２Ｘ４＋０．２９５９Ｘ５。     

Ascorbic acid ameliorates dysregulated folliculogenesis induced by mono-(2-ethylhexyl)phthalate in neonatal mouse ovaries via reducing ovarian oxidative stress

Phthalates, including di-(2-ethylhexyl)phthalate (DEHP), are common industrial chemicals in the environment. Recent evidence indicates that DEHP and its active metabolite mono-(2-ethylhexyl)phthalate (MEHP) negatively modulate reproductive functions and induce reactive oxygen species. Ascorbic acid (AA) is a dietary requirement for primates, and it acts as a potent free radical scavenger to protect tissues against oxidative stress. In this study, to investigate the toxic effects of MEHP on the follicle development and the beneficial role of AA, neonatal mouse ovaries were treated with different concentrations of MEHP with or without AA for 6 days. Then, the follicle constitution and oxidative status were compared in different groups. Results showed MEHP accelerated primordial follicle recruitment by increasing the percentage of primary and secondary follicles and decreasing the percentage of primordial follicles in the ovaries. Moreover, MEHP-induced ovarian oxidative stress by significantly increasing malondialdehyde (MDA) concentration and the expression of GSS and SOD1. When ovaries were co-administrated with MEHP and AA, follicle constitution was normalized, and the oxidative status was significantly decreased. These results suggested that AA ameliorated MEHP-induced ovarian oxidative stress and follicular dysregulation, which attested the clinical significance of AA for ovary protection in the case of MEHP exposure.     

Fatty acid composition of intramuscular fat from Nellore steers fed dry or high moisture corn and calcium salts of fatty acids

The purpose of this work was to evaluate the fatty acid composition of the Longissimus muscle from carcasses of Nellore steers fed diets with calcium salts of fatty acids (CSFA) and high moisture corn. Forty eight steers were fed during 70 days four diets containing dry corn (DC), high moisture corn (HM), dry corn plus CSFA (DC-CSFA) or high moisture corn plus CSFA (HM-CSFA). Fatty acid composition of the Longissimus muscle was determined by gas chromatography. Corn type had no effect on the ether extract percentage and in the content of the majority of the fatty acids, although steers fed HMC showed higher levels of polyunsaturated fatty acids and polyunsaturated/saturated ratio. Feeding CSFA increased ether extract percentage but had no effect on total of saturated, unsaturated and saturated: unsaturated ratio. Both high moisture corn and calcium salts of fatty acids increased CLA (cis9, trans11) and total CLA concentrations in intramuscular fat.     

Concentration of conjugated linoleic acid in grazing sheep and goat milk fat

The conjugated linoleic acid (CLA) content of grazing sheep and goat milk fat, throughout their lactation period, was examined. Six sheep and six goat representative farms were selected at random and milk samples were taken at monthly intervals for fatty acids profile determination. Sheep and goat nutrition was based on natural grazing and on supplementary feeding during the winter months. From April onwards, grazing native pastures was the only source of feed for sheep and goats. The University farm whose sheep are kept indoors all year round without any grazing, was also used as reference. Fifteen individual milk samples were also taken in April from a sheep and goat farm respectively, in order to see the variability of CLA inside the farm. The results showed that: a. the CLA content of grazing sheep and goat milk fat increased significantly in April–May (early growth stage of grass) and then declined while that of indoors kept sheep was more or less constant during the same period, b. the isomers cis-9, trans-11 and trans-10, cis-12 of CLA were found in grazing sheep milk fat, while in indoors kept sheep and goats' milk fat only the cis-9, trans-11 isomer was found, c. the CLA content of sheep milk fat was much higher than that of goats, d. a negative correlation between sheep milk fat and CLA content was found and e. there was considerable variation in milk fat CLA content between sheep and goat farms and inside the farms.     

近红外光谱分析技术在测定饲料中植酸磷含量上的应用

植酸是一种抗营养因子。传统的用三氯化铁沉淀植酸的化学分析法费时费工,不能满足饲料工业发展的需要。为了寻求快速检测饲料中植酸磷(简称P.P.)含量的手段,本试验运用近红外光谱分析技术(简称 NIRS),分别以植酸磷含量较高的米糠饼和植酸磷含量较低的高粱为样品,对这两种饲料的化学分析法测值与近红外光谱法测值进行了比较。试验结果表明:用48个米糠饼样品和50个高粱样品进行定标,相关系数(R,下同)分别为0.901和0.890,残余标准差(RSD,下同)分别为0.06和0.03;另用不参与定标的25个米糠饼样品和21个高粱样品对定标结果进行检验,R 分别为0.803和0.917,RSD 分别为0.07和0.02。NIRS 法的分析精度基本上可以达到化学分析法的要求。作者认为,达项技术作为饲料中 PP 含量快速分析的手段是可行的。     

牛乳脂共轭亚油酸的合成及其营养调控

共轭亚油酸(CLA)是存在于动物脂肪和乳脂中的天然活性成分。本文综述了牛乳脂CLA的来源、合成机制及其营养调控。     

青霉酸毒性研究进展

青霉酸是圆弧青霉代谢产物的主要成分。现已证明,青霉酸对各种动物具有毒性,主要引起心脏、肝脏和肾脏等器官的损伤,并具有潜在致癌性。青霉酸在饲料中的含量很高,而且污染极其广泛。因此,研究青霉酸的毒性、中毒机理及与其他毒素的联合作用,对保证饲料卫生和动物健康具有很重要的意义,该文就青霉酸的器官毒性、细胞毒性、分子毒性及联合毒性的研究进行综述。