很快2018年4月份的雅思又臨近了，同學(xué)們做好準(zhǔn)備沒(méi)有呢？今天就和出國(guó)留學(xué)網(wǎng)的小編一起來(lái)看看2018年4月21日雅思閱讀題目預(yù)測(cè)Newly Hatched birds
雅思閱讀文章題目 Newly Hatched birds
重復(fù)年份 20150430 20130718 20100821 20070922
雅思閱讀題材 動(dòng)物
雅思閱讀題型 暫無(wú)
雅思閱讀文章大意 有一種通過(guò)敲擊蛋殼加速蛋的孵化，并解釋了同時(shí)孵化的原因。后面又比較了各種鳥(niǎo)的喂食方式。
參考閱讀：
The changes in body weight and composition were examined in broilers that either had immediate access to feed and water or had not been fed for 48 h posthatch. Chicks without access to feed decreased in BW by 7.8% in the 48 h posthatch， which was equivalent to 5.3 kcal/45 g chick/d. However， during this period the small intestines increased in weight and protein content by 80% or more. The decrease in yolk fat and protein could account for most of the changes in body composition in the feed-deprived chick. In contrast， fed chicks grew by 5 g and used 4.5 kcal/d for maintenance； during this period small intestines increased in weight by 110%. Intestinal absorption of exogenous nutrients was determined from hatch through 4 d posthatch by administration of a bolus of labeled glucose， methionine， or oleic acid， together with a nonabsorbed reference substance. Absorption of fatty acids was more than 80% at hatch and was higher than that of glucose and methionine， which was low especially when the bolus was administered as a solution. Absorption of all components tested increased with age and was more than 80% on Day 4. Duodenal in situ uptake determinations in hatching chicks indicated that uptake of oleic acid was high from yolk and saline solutions compared with glucose and methionine， which exhibited low uptake from yolk but higher uptake from saline solutions. These studies indicate that， although the small intestine has the capacity to absorb carbohydrates and amino acids at hatch， uptake may be dependant on the development of suitable conditions， including sufficient pancreatic and brush border enzymes for digestion and adequate sodium for function of the glucose-sodium cotransporters.