开食时间对雏鸡早期生长和内脏器官发育的影响

本试验旨在研究不同开食时间对雏鸡早期的生长性能及内脏器官发育的影响.试验选取1080只0日龄、体重相近的新扬州鸡雏鸡,根据开食时间不同,随机分成6个组,每个组3个重复,每个重复60只(30只公鸡,30只母鸡).出壳后一周内,每天从每个重复中随机挑选8只雏鸡(4公4母),分别称其活重后致死,取卵黄囊、肝脏、心脏、胰腺、法氏囊和小肠分别称重,测量小肠长度.结果表明,出壳后禁食36h对7日龄鸡体重没有显著负面影响,出壳后最长禁食时间不应超过60h.     

氮磷肥对3种牧草的生长效应和氮磷吸收的影响

采用田间试验,单因素随机区组排列,以豆科牧草柱花草和禾本科牧草扭黄茅和孔颖草为试验材料,研究适量氮磷肥的施用对3种牧草旺盛期生长及土壤氮磷吸收的影响和效果。试验结果表明,与未施氮磷肥比较,氮磷的施用有利柱花草、扭黄茅和孔颖草旺盛期(7-9月)的生长,3种牧草物候期有所延迟,可以提高3种牧草旺盛期绝对生长量,显著增加了孔颖草总生物量和氮吸收量(P<0.05)。与未施氮肥对比,施氮(施纯氮120 kg·hm^-2)有利柱花草和孔颖草对氮的吸收,显著提高柱花草含氮量和孔颖草氮的吸收量(P<0.05),促进柱花草和孔颖草的生长,提高柱花草和孔颖草地上部和地下部生物量,提高扭黄茅地上部的生长量和生物量。与未施磷肥对比,施磷(施纯磷75 kg·hm^-2)显著提高孔颖草氮的吸收量(P<0.05)。本研究为3种牧草和其他牧草氮磷的施用提供理论依据,即:适量的氮磷施用有利3种牧草产量的提高。     

Microbial protein formation of different carbohydrates in vitro

The aim of this study was to investigate the microbial protein yield of different pure carbohydrates to contribute to a more precise prediction of the microbial protein formed in the rumen. In a first experiment, sucrose, wheat starch, microcrystalline cellulose and citrus pectin were incubated for 8 and 24 hr in the modified Hohenheim gas test (HGT) system (3 runs × 2 syringes) including gas production, ammonia and short‐chain fatty acid concentration measurements. Ammonia values were used for estimation of the microbial protein formation. In a second experiment, the same substrates were incubated for 96 hr in the HGT system (2 runs × 3 syringes) and gas production was measured after 2, 4, 6, 8, 12, 16, 24, 30, 36, 48, 60, 72 and 96 hr of incubation to obtain the fermentation kinetics and the time of half‐maximal gas production (t_1/2) of the substrates. The substrates differed considerably in their fermentation kinetics, and therefore, comparison on the basis of t_1/2 was chosen as the most meaningful. At t_1/2, microbial protein yield [g/kg dry matter] was higher for cellulose than for sucrose and pectin and higher for starch than for sucrose. The microbial protein expressed in g/L gas production was higher for starch and cellulose than for sucrose and pectin at t_1/2. Effects of carbohydrates related to ruminal pH may remain undetected in in vitro trials.     

Describing the growth and molt of modern domestic turkey (Meleagris gallopavo) primary wing feathers

The use of feathers as noninvasive physiological measurements of biomarkers in poultry research is expanding. Feather molting patterns and growth rates, however, are not well described in domestic poultry. These parameters could influence the measurement of these biomarkers. Therefore, the objective of this study was to describe the juvenile primary feather molting patterns and feather growth rates for domestic turkeys. The 10 primary wing feathers of 48 female turkeys were measured weekly from week 1 (0 d of age) to week 20. Feathers were manually measured, and the presence or absence of each primary feather was recorded weekly. Generalized linear mixed models were used to investigate if feather growth differed between the primary feathers. The molting of the juvenile primary feathers followed a typical descending pattern starting with P1 (5 wk of age), while P9 and P10 had not molted by the end of the study (20 wk of age). The average feather growth rate was 2.4 cm/wk, although there was a significant difference between the 10 primary feathers (P < 0.0001, 2.1 to 2.8 cm/wk). Over time, feather growth followed a pattern where the growth rate reaches a peak and then declines until the feather is molted. The results of this study provide a critical update of patterns of molting and feather growth in primary wing feathers of modern turkeys. This can have implications for the interpretation of physiological biomarkers, such as the longitudinal deposition of corticosterone, in the feathers of domestic turkeys.     

谷氨酰胺对肉仔鸡生长性能和盲肠沙门氏菌定植的影响

文章旨在研究谷氨酰胺对肉鸡生长性能和盲肠沙门氏菌水平的影响。试验1选择1日龄AA肉仔鸡234只,随机分为3组,每组3个重复,每个重复26只鸡,对照组饲喂玉米-豆粕型日粮,处理1组饲喂基础日粮(在3日龄感染3.6×10^6cfu沙门氏菌),处理2组饲喂基础日粮+10g/kg谷氨酰胺(在3日龄感染3.6×10^6cfu沙门氏菌)。试验2选择1日龄AA肉仔鸡312只,随机分为4组,每组3个重复,每个重复26只鸡,对照组和处理1组同试验1,处理3组同试验1的处理2组,但肉鸡感染7.5×10^6cfu沙门氏菌试验2处理2组饲喂基础日粮+10g/kg谷氨酰胺(不感染沙门氏菌)。两个试验均开展14d。试验1:日粮添加谷氨酰胺对肉鸡生长性能无显著影响(P>0.05)。试验2:处理2组较其他组显著提高了1~7d肉鸡的体重和日增重(P<0.05)。肉鸡感染沙门氏菌4或10d后,日粮添加谷氨酰胺对盲肠沙门氏菌含量无显著影响(P>0.05)。结论:日粮添加1%谷氨酰胺可以提高肉鸡生长性能,但并没有降低盲肠沙门氏菌水平,这说明日粮中添加1%谷氨酰胺不足以达到降低盲肠沙门氏菌的最佳水平。     

香根草的栽培管理方法研究

香根草作为水土保持与环境治理植物目前在热带、亚热带地区得到越来越广泛的应用。然而，香根草不结实，只能通过无性繁殖，繁殖速度相对较慢。因此，如何加快香根草的繁殖速度便成了研究该植物的一个重要课题。目前各地所采取的繁殖栽培与管理方法各不相同。通过现场观测，并总结过去的繁苗经验，提出了8项应采取的栽培管理措施：1)苗圃应选在阳光充足、无遮荫的地段；2)苗圃地应土壤肥沃，宜沙不宜粘，不要有积水；3)注意施肥，磷肥与有机肥作基肥，复合肥作追肥；4)种植前将香根草地上部分剪至30～40cm，根系剪至5～15cm；5)考虑斜植，且种植深度要恰当；6)种植密度要合理；7)适度剪割，清除杂草；8)1年出苗。     

牛磺酸对笼养蛋雏鸭生长性能、抗氧化功能及免疫器官发育的影响

本试验旨在研究牛磺酸对笼养蛋雏鸭生长性能、抗氧化功能及免疫器官发育的影响.试验采用单因素完全随机分组设计,选择健康1日龄金定蛋雏鸭240只,随机分为5个组(每个组6个重复,每个重复8只鸭),分别饲喂在玉米-豆粕型基础饲粮基础上添加0.05%、0.10%、0.15%、0.20%牛磺酸的试验饲粮.试验期4周.结果表明:饲粮...     

日粮蛋白质水平对育雏期绿头野鸭生长性能的影响

本研究选用刚出壳的绿头野鸭90只,随机分成3组,每组30只,分别饲喂能量相同,蛋白质水平分别为17.00%、19.00%、21.00%的饲粮,通过饲养和代谢试验研究不同蛋白质水平日粮对育雏期(0～4周龄)绿头野鸭生长性能的影响。结果表明,随着饲粮蛋白质水平的提高,蛋白质的代谢率逐渐下降,各组间差异不显著(P>0.05)。从饲料报酬的角度看,19.00%的蛋白质水平完全可以满足绿头野鸭育雏期(0～4周龄)的生长需要。     

Optimal dietary taurine level for growth of juvenile Japanese flounder Paralichthys olivaceus

The requirement for taurine in juvenile Japanese flounder Paralichthys olivaceus was determined by feeding diets containing various levels of taurine and cystine. Test diets supplemented with 0.5, 1.0 and 1.5% of taurine or with 0.5, 1.0 and 1.5% of L -cystine were prepared. The basal diet contained 55% protein from white fish meal. These diets were fed to juvenile Japanese flounder with an initial mean bodyweight of 0.9 g (total length (TL) 48 mm) for 5 weeks. Approximately 1.4% taurine content in the diet was required for optimum growth of juvenile flounder. A positive linear relationship was noted between the content of taurine accumulated in the muscle, liver and brain and the level of taurine in the diet. However, there was no increased taurine content in tissues of fish fed the cystine-supplemented diet. In contrast, the fish fed control and cystine-supplemented diets showed higher contents of cystathionine in the tissues. The concentration of cystathionine in tissues rapidly decreased with an increase of taurine in the diet. It was also observed that for each of the dietary groups, a trace amount of taurine was excreted. These results suggest that the taurine content in the diet affects the sulfur amino acid metabolism of juvenile Japanese flounder, and indicate that juvenile flounder are unable to biosynthesize taurine from cystine.